Merge branch 'for-linus' of git://git.kernel.dk/data/git/linux-2.6-block

* 'for-linus' of git://git.kernel.dk/data/git/linux-2.6-block: (63 commits) Fix memory leak in dm-crypt SPARC64: sg chaining support SPARC: sg chaining support PPC: sg chaining support PS3: sg chaining support IA64: sg chaining support x86-64: enable sg chaining x86-64: update pci-gart iommu to sg helpers x86-64: update nommu to sg helpers x86-64: update calgary iommu to sg helpers swiotlb: sg chaining support i386: enable sg chaining i386 dma_map_sg: convert to using sg helpers mmc: need to zero sglist on init Panic in blk_rq_map_sg() from CCISS driver remove sglist_len remove blk_queue_max_phys_segments in libata revert sg segment size ifdefs Fixup u14-34f ENABLE_SG_CHAINING qla1280: enable use_sg_chaining option ...
author: Linus Torvalds <torvalds@woody.linux-foundation.org> 2007-10-16 21:09:16 +0400
committer: Linus Torvalds <torvalds@woody.linux-foundation.org> 2007-10-16 21:09:16 +0400
commit: 92d15c2ccbb3e31a3fc71ad28fdb55e1319383c0 (patch)
tree: 8d83c0dc3c6b935d8367e331872f242b742f0a8a
parent: f20bf6125605acbbc7eb8c9420d7221c91aa83eb (diff)
parent: 644bd2f048972d75eb1979b1fdca257d528ce687 (diff)
download: linux-92d15c2ccbb3e31a3fc71ad28fdb55e1319383c0.tar.xz
142 files changed, 1186 insertions, 1115 deletions
diff --git a/Documentation/DMA-mapping.txt b/Documentation/DMA-mapping.txt
index e07f2530326b..3c8ae020b6a7 100644
--- a/Documentation/DMA-mapping.txt
+++ b/Documentation/DMA-mapping.txt
@@ -514,7 +514,7 @@ With scatterlists, you map a region gathered from several regions by:
 	int i, count = pci_map_sg(dev, sglist, nents, direction);
 	struct scatterlist *sg;
 
-	for (i = 0, sg = sglist; i < count; i++, sg++) {
+	for_each_sg(sglist, sg, count, i) {
 		hw_address[i] = sg_dma_address(sg);
 		hw_len[i] = sg_dma_len(sg);
 	}
@@ -782,5 +782,5 @@ following people:
 	Jay Estabrook <Jay.Estabrook@compaq.com>
 	Thomas Sailer <sailer@ife.ee.ethz.ch>
 	Andrea Arcangeli <andrea@suse.de>
-	Jens Axboe <axboe@suse.de>
+	Jens Axboe <jens.axboe@oracle.com>
 	David Mosberger-Tang <davidm@hpl.hp.com>
diff --git a/Documentation/HOWTO b/Documentation/HOWTO
index c64e969dc33b..dceb30921498 100644
--- a/Documentation/HOWTO
+++ b/Documentation/HOWTO
@@ -330,7 +330,7 @@ Here is a list of some of the different kernel trees available:
     - ACPI development tree, Len Brown <len.brown@intel.com>
 	git.kernel.org:/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6.git
 
-    - Block development tree, Jens Axboe <axboe@suse.de>
+    - Block development tree, Jens Axboe <jens.axboe@oracle.com>
 	git.kernel.org:/pub/scm/linux/kernel/git/axboe/linux-2.6-block.git
 
     - DRM development tree, Dave Airlie <airlied@linux.ie>
diff --git a/Documentation/block/00-INDEX b/Documentation/block/00-INDEX
new file mode 100644
index 000000000000..961a0513f8c3
--- /dev/null
+++ b/Documentation/block/00-INDEX
@@ -0,0 +1,20 @@
+00-INDEX
+	- This file
+as-iosched.txt
+	- Anticipatory IO scheduler
+barrier.txt
+	- I/O Barriers
+biodoc.txt
+	- Notes on the Generic Block Layer Rewrite in Linux 2.5
+capability.txt
+	- Generic Block Device Capability (/sys/block/<disk>/capability)
+deadline-iosched.txt
+	- Deadline IO scheduler tunables
+ioprio.txt
+	- Block io priorities (in CFQ scheduler)
+request.txt
+	- The members of struct request (in include/linux/blkdev.h)
+stat.txt
+	- Block layer statistics in /sys/block/<dev>/stat
+switching-sched.txt
+	- Switching I/O schedulers at runtime
diff --git a/Documentation/block/as-iosched.txt b/Documentation/block/as-iosched.txt
index a598fe10a297..738b72be128e 100644
--- a/Documentation/block/as-iosched.txt
+++ b/Documentation/block/as-iosched.txt
@@ -20,15 +20,10 @@ actually has a head for each physical device in the logical RAID device.
 However, setting the antic_expire (see tunable parameters below) produces
 very similar behavior to the deadline IO scheduler.
 
-
 Selecting IO schedulers
 -----------------------
-To choose IO schedulers at boot time, use the argument 'elevator=deadline'.
-'noop', 'as' and 'cfq' (the default) are also available. IO schedulers are
-assigned globally at boot time only presently. It's also possible to change
-the IO scheduler for a determined device on the fly, as described in
-Documentation/block/switching-sched.txt.
-
+Refer to Documentation/block/switching-sched.txt for information on
+selecting an io scheduler on a per-device basis.
 
 Anticipatory IO scheduler Policies
 ----------------------------------
@@ -115,7 +110,7 @@ statistics (average think time, average seek distance) on the process
 that submitted the just completed request are examined.  If it seems
 likely that that process will submit another request soon, and that
 request is likely to be near the just completed request, then the IO
-scheduler will stop dispatching more read requests for up time (antic_expire)
+scheduler will stop dispatching more read requests for up to (antic_expire)
 milliseconds, hoping that process will submit a new request near the one
 that just completed.  If such a request is made, then it is dispatched
 immediately.  If the antic_expire wait time expires, then the IO scheduler
@@ -165,3 +160,13 @@ The parameters are:
     for big seek time devices though not a linear correspondence - most
     processes have only a few ms thinktime.
 
+In addition to the tunables above there is a read-only file named est_time
+which, when read, will show:
+
+    - The probability of a task exiting without a cooperating task
+      submitting an anticipated IO.
+
+    - The current mean think time.
+
+    - The seek distance used to determine if an incoming IO is better.
+
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index dc3f49e3e539..93f223b9723f 100644
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -2,7 +2,7 @@
 	=====================================================
 
 Notes Written on Jan 15, 2002:
-	Jens Axboe <axboe@suse.de>
+	Jens Axboe <jens.axboe@oracle.com>
 	Suparna Bhattacharya <suparna@in.ibm.com>
 
 Last Updated May 2, 2002
@@ -21,7 +21,7 @@ Credits:
 ---------
 
 2.5 bio rewrite:
-	Jens Axboe <axboe@suse.de>
+	Jens Axboe <jens.axboe@oracle.com>
 
 Many aspects of the generic block layer redesign were driven by and evolved
 over discussions, prior patches and the collective experience of several
diff --git a/Documentation/block/deadline-iosched.txt b/Documentation/block/deadline-iosched.txt
index be08ffd1e9b8..c23cab13c3d1 100644
--- a/Documentation/block/deadline-iosched.txt
+++ b/Documentation/block/deadline-iosched.txt
@@ -5,16 +5,10 @@ This little file attempts to document how the deadline io scheduler works.
 In particular, it will clarify the meaning of the exposed tunables that may be
 of interest to power users.
 
-Each io queue has a set of io scheduler tunables associated with it. These
-tunables control how the io scheduler works. You can find these entries
-in:
-
-/sys/block/<device>/queue/iosched
-
-assuming that you have sysfs mounted on /sys. If you don't have sysfs mounted,
-you can do so by typing:
-
-# mount none /sys -t sysfs
+Selecting IO schedulers
+-----------------------
+Refer to Documentation/block/switching-sched.txt for information on
+selecting an io scheduler on a per-device basis.
 
 
 ********************************************************************************
@@ -41,14 +35,11 @@ fifo_batch
 
 When a read request expires its deadline, we must move some requests from
 the sorted io scheduler list to the block device dispatch queue. fifo_batch
-controls how many requests we move, based on the cost of each request. A
-request is either qualified as a seek or a stream. The io scheduler knows
-the last request that was serviced by the drive (or will be serviced right
-before this one). See seek_cost and stream_unit.
+controls how many requests we move.
 
 
-write_starved	(number of dispatches)
--------------
+writes_starved	(number of dispatches)
+--------------
 
 When we have to move requests from the io scheduler queue to the block
 device dispatch queue, we always give a preference to reads. However, we
@@ -73,6 +64,6 @@ that comes at basically 0 cost we leave that on. We simply disable the
 rbtree front sector lookup when the io scheduler merge function is called.
 
 
-Nov 11 2002, Jens Axboe <axboe@suse.de>
+Nov 11 2002, Jens Axboe <jens.axboe@oracle.com>
 
 
diff --git a/Documentation/block/ioprio.txt b/Documentation/block/ioprio.txt
index 35e516b0b8a9..8ed8c59380b4 100644
--- a/Documentation/block/ioprio.txt
+++ b/Documentation/block/ioprio.txt
@@ -180,4 +180,4 @@ int main(int argc, char *argv[])
 ---> snip ionice.c tool <---
 
 
-March 11 2005, Jens Axboe <axboe@suse.de>
+March 11 2005, Jens Axboe <jens.axboe@oracle.com>
diff --git a/Documentation/block/request.txt b/Documentation/block/request.txt
index fff58acb40a3..754e104ed369 100644
--- a/Documentation/block/request.txt
+++ b/Documentation/block/request.txt
@@ -1,7 +1,7 @@
 
 struct request documentation
 
-Jens Axboe <axboe@suse.de> 27/05/02
+Jens Axboe <jens.axboe@oracle.com> 27/05/02
 
 1.0
 Index
diff --git a/Documentation/block/switching-sched.txt b/Documentation/block/switching-sched.txt
index 5fa130a67531..634c952e1964 100644
--- a/Documentation/block/switching-sched.txt
+++ b/Documentation/block/switching-sched.txt
@@ -1,3 +1,18 @@
+To choose IO schedulers at boot time, use the argument 'elevator=deadline'.
+'noop', 'as' and 'cfq' (the default) are also available. IO schedulers are
+assigned globally at boot time only presently.
+
+Each io queue has a set of io scheduler tunables associated with it. These
+tunables control how the io scheduler works. You can find these entries
+in:
+
+/sys/block/<device>/queue/iosched
+
+assuming that you have sysfs mounted on /sys. If you don't have sysfs mounted,
+you can do so by typing:
+
+# mount none /sys -t sysfs
+
 As of the Linux 2.6.10 kernel, it is now possible to change the
 IO scheduler for a given block device on the fly (thus making it possible,
 for instance, to set the CFQ scheduler for the system default, but
@@ -20,3 +35,9 @@ noop anticipatory deadline [cfq]
 # echo anticipatory > /sys/block/hda/queue/scheduler
 # cat /sys/block/hda/queue/scheduler
 noop [anticipatory] deadline cfq
+
+Each io queue has a set of io scheduler tunables associated with it. These
+tunables control how the io scheduler works. You can find these entries
+in:
+
+/sys/block/<device>/queue/iosched
diff --git a/arch/ia64/hp/common/sba_iommu.c b/arch/ia64/hp/common/sba_iommu.c
index e980e7aa2306..4338f4123f31 100644
--- a/arch/ia64/hp/common/sba_iommu.c
+++ b/arch/ia64/hp/common/sba_iommu.c
@@ -396,7 +396,7 @@ sba_dump_sg( struct ioc *ioc, struct scatterlist *startsg, int nents)
 		printk(KERN_DEBUG " %d : DMA %08lx/%05x CPU %p\n", nents,
 		       startsg->dma_address, startsg->dma_length,
 		       sba_sg_address(startsg));
-		startsg++;
+		startsg = sg_next(startsg);
 	}
 }
 
@@ -409,7 +409,7 @@ sba_check_sg( struct ioc *ioc, struct scatterlist *startsg, int nents)
 	while (the_nents-- > 0) {
 		if (sba_sg_address(the_sg) == 0x0UL)
 			sba_dump_sg(NULL, startsg, nents);
-		the_sg++;
+		the_sg = sg_next(the_sg);
 	}
 }
 
@@ -1201,7 +1201,7 @@ sba_fill_pdir(
 			u32 pide = startsg->dma_address & ~PIDE_FLAG;
 			dma_offset = (unsigned long) pide & ~iovp_mask;
 			startsg->dma_address = 0;
-			dma_sg++;
+			dma_sg = sg_next(dma_sg);
 			dma_sg->dma_address = pide | ioc->ibase;
 			pdirp = &(ioc->pdir_base[pide >> iovp_shift]);
 			n_mappings++;
@@ -1228,7 +1228,7 @@ sba_fill_pdir(
 				pdirp++;
 			} while (cnt > 0);
 		}
-		startsg++;
+		startsg = sg_next(startsg);
 	}
 	/* force pdir update */
 	wmb();
@@ -1297,7 +1297,7 @@ sba_coalesce_chunks( struct ioc *ioc,
 		while (--nents > 0) {
 			unsigned long vaddr;	/* tmp */
 
-			startsg++;
+			startsg = sg_next(startsg);
 
 			/* PARANOID */
 			startsg->dma_address = startsg->dma_length = 0;
@@ -1407,7 +1407,7 @@ int sba_map_sg(struct device *dev, struct scatterlist *sglist, int nents, int di
 #ifdef ALLOW_IOV_BYPASS_SG
 	ASSERT(to_pci_dev(dev)->dma_mask);
 	if (likely((ioc->dma_mask & ~to_pci_dev(dev)->dma_mask) == 0)) {
-		for (sg = sglist ; filled < nents ; filled++, sg++){
+		for_each_sg(sglist, sg, nents, filled) {
 			sg->dma_length = sg->length;
 			sg->dma_address = virt_to_phys(sba_sg_address(sg));
 		}
@@ -1501,7 +1501,7 @@ void sba_unmap_sg (struct device *dev, struct scatterlist *sglist, int nents, in
 	while (nents && sglist->dma_length) {
 
 		sba_unmap_single(dev, sglist->dma_address, sglist->dma_length, dir);
-		sglist++;
+		sglist = sg_next(sglist);
 		nents--;
 	}
 
diff --git a/arch/ia64/hp/sim/simscsi.c b/arch/ia64/hp/sim/simscsi.c
index d62fa76e5a7d..a3a558a06757 100644
--- a/arch/ia64/hp/sim/simscsi.c
+++ b/arch/ia64/hp/sim/simscsi.c
@@ -360,6 +360,7 @@ static struct scsi_host_template driver_template = {
 	.max_sectors		= 1024,
 	.cmd_per_lun		= SIMSCSI_REQ_QUEUE_LEN,
 	.use_clustering		= DISABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 };
 
 static int __init
diff --git a/arch/ia64/sn/pci/pci_dma.c b/arch/ia64/sn/pci/pci_dma.c
index d79ddacfba2d..ecd8a52b9b9e 100644
--- a/arch/ia64/sn/pci/pci_dma.c
+++ b/arch/ia64/sn/pci/pci_dma.c
@@ -218,16 +218,17 @@ EXPORT_SYMBOL(sn_dma_unmap_single);
  *
  * Unmap a set of streaming mode DMA translations.
  */
-void sn_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
+void sn_dma_unmap_sg(struct device *dev, struct scatterlist *sgl,
 		     int nhwentries, int direction)
 {
 	int i;
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct sn_pcibus_provider *provider = SN_PCIDEV_BUSPROVIDER(pdev);
+	struct scatterlist *sg;
 
 	BUG_ON(dev->bus != &pci_bus_type);
 
-	for (i = 0; i < nhwentries; i++, sg++) {
+	for_each_sg(sgl, sg, nhwentries, i) {
 		provider->dma_unmap(pdev, sg->dma_address, direction);
 		sg->dma_address = (dma_addr_t) NULL;
 		sg->dma_length = 0;
@@ -244,11 +245,11 @@ EXPORT_SYMBOL(sn_dma_unmap_sg);
  *
  * Maps each entry of @sg for DMA.
  */
-int sn_dma_map_sg(struct device *dev, struct scatterlist *sg, int nhwentries,
+int sn_dma_map_sg(struct device *dev, struct scatterlist *sgl, int nhwentries,
 		  int direction)
 {
 	unsigned long phys_addr;
-	struct scatterlist *saved_sg = sg;
+	struct scatterlist *saved_sg = sgl, *sg;
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct sn_pcibus_provider *provider = SN_PCIDEV_BUSPROVIDER(pdev);
 	int i;
@@ -258,7 +259,7 @@ int sn_dma_map_sg(struct device *dev, struct scatterlist *sg, int nhwentries,
 	/*
 	 * Setup a DMA address for each entry in the scatterlist.
 	 */
-	for (i = 0; i < nhwentries; i++, sg++) {
+	for_each_sg(sgl, sg, nhwentries, i) {
 		phys_addr = SG_ENT_PHYS_ADDRESS(sg);
 		sg->dma_address = provider->dma_map(pdev,
 						    phys_addr, sg->length,
diff --git a/arch/powerpc/kernel/dma_64.c b/arch/powerpc/kernel/dma_64.c
index 7b0e754383cf..9001104b56b0 100644
--- a/arch/powerpc/kernel/dma_64.c
+++ b/arch/powerpc/kernel/dma_64.c
@@ -154,12 +154,13 @@ static void dma_direct_unmap_single(struct device *dev, dma_addr_t dma_addr,
 {
 }
 
-static int dma_direct_map_sg(struct device *dev, struct scatterlist *sg,
+static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
 			     int nents, enum dma_data_direction direction)
 {
+	struct scatterlist *sg;
 	int i;
 
-	for (i = 0; i < nents; i++, sg++) {
+	for_each_sg(sgl, sg, nents, i) {
 		sg->dma_address = (page_to_phys(sg->page) + sg->offset) |
 			dma_direct_offset;
 		sg->dma_length = sg->length;
diff --git a/arch/powerpc/kernel/ibmebus.c b/arch/powerpc/kernel/ibmebus.c
index 53bf64623bd8..2e16ca5778a3 100644
--- a/arch/powerpc/kernel/ibmebus.c
+++ b/arch/powerpc/kernel/ibmebus.c
@@ -87,15 +87,16 @@ static void ibmebus_unmap_single(struct device *dev,
 }
 
 static int ibmebus_map_sg(struct device *dev,
-			  struct scatterlist *sg,
+			  struct scatterlist *sgl,
 			  int nents, enum dma_data_direction direction)
 {
+	struct scatterlist *sg;
 	int i;
 
-	for (i = 0; i < nents; i++) {
-		sg[i].dma_address = (dma_addr_t)page_address(sg[i].page)
-			+ sg[i].offset;
-		sg[i].dma_length = sg[i].length;
+	for_each_sg(sgl, sg, nents, i) {
+		sg->dma_address = (dma_addr_t)page_address(sg->page)
+			+ sg->offset;
+		sg->dma_length = sg->length;
 	}
 
 	return nents;
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index e4ec6eee81a8..306a6f75b6c5 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -277,7 +277,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 	dma_addr_t dma_next = 0, dma_addr;
 	unsigned long flags;
 	struct scatterlist *s, *outs, *segstart;
-	int outcount, incount;
+	int outcount, incount, i;
 	unsigned long handle;
 
 	BUG_ON(direction == DMA_NONE);
@@ -297,7 +297,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 
 	spin_lock_irqsave(&(tbl->it_lock), flags);
 
-	for (s = outs; nelems; nelems--, s++) {
+	for_each_sg(sglist, s, nelems, i) {
 		unsigned long vaddr, npages, entry, slen;
 
 		slen = s->length;
@@ -341,7 +341,8 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 			if (novmerge || (dma_addr != dma_next)) {
 				/* Can't merge: create a new segment */
 				segstart = s;
-				outcount++; outs++;
+				outcount++;
+				outs = sg_next(outs);
 				DBG("    can't merge, new segment.\n");
 			} else {
 				outs->dma_length += s->length;
@@ -374,7 +375,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 	 * next entry of the sglist if we didn't fill the list completely
 	 */
 	if (outcount < incount) {
-		outs++;
+		outs = sg_next(outs);
 		outs->dma_address = DMA_ERROR_CODE;
 		outs->dma_length = 0;
 	}
@@ -385,7 +386,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 	return outcount;
 
  failure:
-	for (s = &sglist[0]; s <= outs; s++) {
+	for_each_sg(sglist, s, nelems, i) {
 		if (s->dma_length != 0) {
 			unsigned long vaddr, npages;
 
@@ -395,6 +396,8 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 			s->dma_address = DMA_ERROR_CODE;
 			s->dma_length = 0;
 		}
+		if (s == outs)
+			break;
 	}
 	spin_unlock_irqrestore(&(tbl->it_lock), flags);
 	return 0;
@@ -404,6 +407,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 		int nelems, enum dma_data_direction direction)
 {
+	struct scatterlist *sg;
 	unsigned long flags;
 
 	BUG_ON(direction == DMA_NONE);
@@ -413,15 +417,16 @@ void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 
 	spin_lock_irqsave(&(tbl->it_lock), flags);
 
+	sg = sglist;
 	while (nelems--) {
 		unsigned int npages;
-		dma_addr_t dma_handle = sglist->dma_address;
+		dma_addr_t dma_handle = sg->dma_address;
 
-		if (sglist->dma_length == 0)
+		if (sg->dma_length == 0)
 			break;
-		npages = iommu_num_pages(dma_handle,sglist->dma_length);
+		npages = iommu_num_pages(dma_handle, sg->dma_length);
 		__iommu_free(tbl, dma_handle, npages);
-		sglist++;
+		sg = sg_next(sg);
 	}
 
 	/* Flush/invalidate TLBs if necessary. As for iommu_free(), we
diff --git a/arch/powerpc/platforms/ps3/system-bus.c b/arch/powerpc/platforms/ps3/system-bus.c
index 190ff4b59a55..07e64b48e7fc 100644
--- a/arch/powerpc/platforms/ps3/system-bus.c
+++ b/arch/powerpc/platforms/ps3/system-bus.c
@@ -616,17 +616,18 @@ static void ps3_unmap_single(struct device *_dev, dma_addr_t dma_addr,
 	}
 }
 
-static int ps3_sb_map_sg(struct device *_dev, struct scatterlist *sg, int nents,
-	enum dma_data_direction direction)
+static int ps3_sb_map_sg(struct device *_dev, struct scatterlist *sgl,
+	int nents, enum dma_data_direction direction)
 {
 #if defined(CONFIG_PS3_DYNAMIC_DMA)
 	BUG_ON("do");
 	return -EPERM;
 #else
 	struct ps3_system_bus_device *dev = ps3_dev_to_system_bus_dev(_dev);
+	struct scatterlist *sg;
 	int i;
 
-	for (i = 0; i < nents; i++, sg++) {
+	for_each_sg(sgl, sg, nents, i) {
 		int result = ps3_dma_map(dev->d_region,
 			page_to_phys(sg->page) + sg->offset, sg->length,
 					 &sg->dma_address, 0);
diff --git a/arch/sparc/kernel/ioport.c b/arch/sparc/kernel/ioport.c
index 62182d2d7b0d..9c3ed88853f3 100644
--- a/arch/sparc/kernel/ioport.c
+++ b/arch/sparc/kernel/ioport.c
@@ -35,6 +35,7 @@
 #include <linux/slab.h>
 #include <linux/pci.h>		/* struct pci_dev */
 #include <linux/proc_fs.h>
+#include <linux/scatterlist.h>
 
 #include <asm/io.h>
 #include <asm/vaddrs.h>
@@ -717,19 +718,19 @@ void pci_unmap_page(struct pci_dev *hwdev,
  * Device ownership issues as mentioned above for pci_map_single are
  * the same here.
  */
-int pci_map_sg(struct pci_dev *hwdev, struct scatterlist *sg, int nents,
+int pci_map_sg(struct pci_dev *hwdev, struct scatterlist *sgl, int nents,
     int direction)
 {
+	struct scatterlist *sg;
 	int n;
 
 	BUG_ON(direction == PCI_DMA_NONE);
 	/* IIep is write-through, not flushing. */
-	for (n = 0; n < nents; n++) {
+	for_each_sg(sgl, sg, nents, n) {
 		BUG_ON(page_address(sg->page) == NULL);
 		sg->dvma_address =
 			virt_to_phys(page_address(sg->page)) + sg->offset;
 		sg->dvma_length = sg->length;
-		sg++;
 	}
 	return nents;
 }
@@ -738,19 +739,19 @@ int pci_map_sg(struct pci_dev *hwdev, struct scatterlist *sg, int nents,
  * Again, cpu read rules concerning calls here are the same as for
  * pci_unmap_single() above.
  */
-void pci_unmap_sg(struct pci_dev *hwdev, struct scatterlist *sg, int nents,
+void pci_unmap_sg(struct pci_dev *hwdev, struct scatterlist *sgl, int nents,
     int direction)
 {
+	struct scatterlist *sg;
 	int n;
 
 	BUG_ON(direction == PCI_DMA_NONE);
 	if (direction != PCI_DMA_TODEVICE) {
-		for (n = 0; n < nents; n++) {
+		for_each_sg(sgl, sg, nents, n) {
 			BUG_ON(page_address(sg->page) == NULL);
 			mmu_inval_dma_area(
 			    (unsigned long) page_address(sg->page),
 			    (sg->length + PAGE_SIZE-1) & PAGE_MASK);
-			sg++;
 		}
 	}
 }
@@ -789,34 +790,34 @@ void pci_dma_sync_single_for_device(struct pci_dev *hwdev, dma_addr_t ba, size_t
  * The same as pci_dma_sync_single_* but for a scatter-gather list,
  * same rules and usage.
  */
-void pci_dma_sync_sg_for_cpu(struct pci_dev *hwdev, struct scatterlist *sg, int nents, int direction)
+void pci_dma_sync_sg_for_cpu(struct pci_dev *hwdev, struct scatterlist *sgl, int nents, int direction)
 {
+	struct scatterlist *sg;
 	int n;
 
 	BUG_ON(direction == PCI_DMA_NONE);
 	if (direction != PCI_DMA_TODEVICE) {
-		for (n = 0; n < nents; n++) {
+		for_each_sg(sgl, sg, nents, n) {
 			BUG_ON(page_address(sg->page) == NULL);
 			mmu_inval_dma_area(
 			    (unsigned long) page_address(sg->page),
 			    (sg->length + PAGE_SIZE-1) & PAGE_MASK);
-			sg++;
 		}
 	}
 }
 
-void pci_dma_sync_sg_for_device(struct pci_dev *hwdev, struct scatterlist *sg, int nents, int direction)
+void pci_dma_sync_sg_for_device(struct pci_dev *hwdev, struct scatterlist *sgl, int nents, int direction)
 {
+	struct scatterlist *sg;
 	int n;
 
 	BUG_ON(direction == PCI_DMA_NONE);
 	if (direction != PCI_DMA_TODEVICE) {
-		for (n = 0; n < nents; n++) {
+		for_each_sg(sgl, sg, nents, n) {
 			BUG_ON(page_address(sg->page) == NULL);
 			mmu_inval_dma_area(
 			    (unsigned long) page_address(sg->page),
 			    (sg->length + PAGE_SIZE-1) & PAGE_MASK);
-			sg++;
 		}
 	}
 }
diff --git a/arch/sparc/mm/io-unit.c b/arch/sparc/mm/io-unit.c
index 7c89893b1fe8..375b4db63704 100644
--- a/arch/sparc/mm/io-unit.c
+++ b/arch/sparc/mm/io-unit.c
@@ -11,8 +11,8 @@
 #include <linux/mm.h>
 #include <linux/highmem.h>	/* pte_offset_map => kmap_atomic */
 #include <linux/bitops.h>
+#include <linux/scatterlist.h>
 
-#include <asm/scatterlist.h>
 #include <asm/pgalloc.h>
 #include <asm/pgtable.h>
 #include <asm/sbus.h>
@@ -144,8 +144,9 @@ static void iounit_get_scsi_sgl(struct scatterlist *sg, int sz, struct sbus_bus
 	spin_lock_irqsave(&iounit->lock, flags);
 	while (sz != 0) {
 		--sz;
-		sg[sz].dvma_address = iounit_get_area(iounit, (unsigned long)page_address(sg[sz].page) + sg[sz].offset, sg[sz].length);
-		sg[sz].dvma_length = sg[sz].length;
+		sg->dvma_address = iounit_get_area(iounit, (unsigned long)page_address(sg->page) + sg->offset, sg->length);
+		sg->dvma_length = sg->length;
+		sg = sg_next(sg);
 	}
 	spin_unlock_irqrestore(&iounit->lock, flags);
 }
@@ -173,11 +174,12 @@ static void iounit_release_scsi_sgl(struct scatterlist *sg, int sz, struct sbus_
 	spin_lock_irqsave(&iounit->lock, flags);
 	while (sz != 0) {
 		--sz;
-		len = ((sg[sz].dvma_address & ~PAGE_MASK) + sg[sz].length + (PAGE_SIZE-1)) >> PAGE_SHIFT;
-		vaddr = (sg[sz].dvma_address - IOUNIT_DMA_BASE) >> PAGE_SHIFT;
+		len = ((sg->dvma_address & ~PAGE_MASK) + sg->length + (PAGE_SIZE-1)) >> PAGE_SHIFT;
+		vaddr = (sg->dvma_address - IOUNIT_DMA_BASE) >> PAGE_SHIFT;
 		IOD(("iounit_release %08lx-%08lx\n", (long)vaddr, (long)len+vaddr));
 		for (len += vaddr; vaddr < len; vaddr++)
 			clear_bit(vaddr, iounit->bmap);
+		sg = sg_next(sg);
 	}
 	spin_unlock_irqrestore(&iounit->lock, flags);
 }
diff --git a/arch/sparc/mm/iommu.c b/arch/sparc/mm/iommu.c
index 52e907af9d29..283656d9f6ea 100644
--- a/arch/sparc/mm/iommu.c
+++ b/arch/sparc/mm/iommu.c
@@ -12,8 +12,8 @@
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/highmem.h>	/* pte_offset_map => kmap_atomic */
+#include <linux/scatterlist.h>
 
-#include <asm/scatterlist.h>
 #include <asm/pgalloc.h>
 #include <asm/pgtable.h>
 #include <asm/sbus.h>
@@ -240,7 +240,7 @@ static void iommu_get_scsi_sgl_noflush(struct scatterlist *sg, int sz, struct sb
 		n = (sg->length + sg->offset + PAGE_SIZE-1) >> PAGE_SHIFT;
 		sg->dvma_address = iommu_get_one(sg->page, n, sbus) + sg->offset;
 		sg->dvma_length = (__u32) sg->length;
-		sg++;
+		sg = sg_next(sg);
 	}
 }
 
@@ -254,7 +254,7 @@ static void iommu_get_scsi_sgl_gflush(struct scatterlist *sg, int sz, struct sbu
 		n = (sg->length + sg->offset + PAGE_SIZE-1) >> PAGE_SHIFT;
 		sg->dvma_address = iommu_get_one(sg->page, n, sbus) + sg->offset;
 		sg->dvma_length = (__u32) sg->length;
-		sg++;
+		sg = sg_next(sg);
 	}
 }
 
@@ -285,7 +285,7 @@ static void iommu_get_scsi_sgl_pflush(struct scatterlist *sg, int sz, struct sbu
 
 		sg->dvma_address = iommu_get_one(sg->page, n, sbus) + sg->offset;
 		sg->dvma_length = (__u32) sg->length;
-		sg++;
+		sg = sg_next(sg);
 	}
 }
 
@@ -325,7 +325,7 @@ static void iommu_release_scsi_sgl(struct scatterlist *sg, int sz, struct sbus_b
 		n = (sg->length + sg->offset + PAGE_SIZE-1) >> PAGE_SHIFT;
 		iommu_release_one(sg->dvma_address & PAGE_MASK, n, sbus);
 		sg->dvma_address = 0x21212121;
-		sg++;
+		sg = sg_next(sg);
 	}
 }
 
diff --git a/arch/sparc/mm/sun4c.c b/arch/sparc/mm/sun4c.c
index 005a3e72d4f2..ee6708fc4492 100644
--- a/arch/sparc/mm/sun4c.c
+++ b/arch/sparc/mm/sun4c.c
@@ -17,8 +17,8 @@
 #include <linux/highmem.h>
 #include <linux/fs.h>
 #include <linux/seq_file.h>
+#include <linux/scatterlist.h>
 
-#include <asm/scatterlist.h>
 #include <asm/page.h>
 #include <asm/pgalloc.h>
 #include <asm/pgtable.h>
@@ -1228,8 +1228,9 @@ static void sun4c_get_scsi_sgl(struct scatterlist *sg, int sz, struct sbus_bus *
 {
 	while (sz != 0) {
 		--sz;
-		sg[sz].dvma_address = (__u32)sun4c_lockarea(page_address(sg[sz].page) + sg[sz].offset, sg[sz].length);
-		sg[sz].dvma_length = sg[sz].length;
+		sg->dvma_address = (__u32)sun4c_lockarea(page_address(sg->page) + sg->offset, sg->length);
+		sg->dvma_length = sg->length;
+		sg = sg_next(sg);
 	}
 }
 
@@ -1244,7 +1245,8 @@ static void sun4c_release_scsi_sgl(struct scatterlist *sg, int sz, struct sbus_b
 {
 	while (sz != 0) {
 		--sz;
-		sun4c_unlockarea((char *)sg[sz].dvma_address, sg[sz].length);
+		sun4c_unlockarea((char *)sg->dvma_address, sg->length);
+		sg = sg_next(sg);
 	}
 }
 
diff --git a/arch/sparc64/kernel/iommu.c b/arch/sparc64/kernel/iommu.c
index b35a62167e9c..db3ffcf7a120 100644
--- a/arch/sparc64/kernel/iommu.c
+++ b/arch/sparc64/kernel/iommu.c
@@ -10,6 +10,7 @@
 #include <linux/device.h>
 #include <linux/dma-mapping.h>
 #include <linux/errno.h>
+#include <linux/scatterlist.h>
 
 #ifdef CONFIG_PCI
 #include <linux/pci.h>
@@ -480,7 +481,7 @@ static inline void fill_sg(iopte_t *iopte, struct scatterlist *sg,
 			   unsigned long iopte_protection)
 {
 	struct scatterlist *dma_sg = sg;
-	struct scatterlist *sg_end = sg + nelems;
+	struct scatterlist *sg_end = sg_last(sg, nelems);
 	int i;
 
 	for (i = 0; i < nused; i++) {
@@ -515,7 +516,7 @@ static inline void fill_sg(iopte_t *iopte, struct scatterlist *sg,
 					len -= (IO_PAGE_SIZE - (tmp & (IO_PAGE_SIZE - 1UL)));
 					break;
 				}
-				sg++;
+				sg = sg_next(sg);
 			}
 
 			pteval = iopte_protection | (pteval & IOPTE_PAGE);
@@ -528,24 +529,24 @@ static inline void fill_sg(iopte_t *iopte, struct scatterlist *sg,
 			}
 
 			pteval = (pteval & IOPTE_PAGE) + len;
-			sg++;
+			sg = sg_next(sg);
 
 			/* Skip over any tail mappings we've fully mapped,
 			 * adjusting pteval along the way.  Stop when we
 			 * detect a page crossing event.
 			 */
-			while (sg < sg_end &&
+			while (sg != sg_end &&
 			       (pteval << (64 - IO_PAGE_SHIFT)) != 0UL &&
 			       (pteval == SG_ENT_PHYS_ADDRESS(sg)) &&
 			       ((pteval ^
 				 (SG_ENT_PHYS_ADDRESS(sg) + sg->length - 1UL)) >> IO_PAGE_SHIFT) == 0UL) {
 				pteval += sg->length;
-				sg++;
+				sg = sg_next(sg);
 			}
 			if ((pteval << (64 - IO_PAGE_SHIFT)) == 0UL)
 				pteval = ~0UL;
 		} while (dma_npages != 0);
-		dma_sg++;
+		dma_sg = sg_next(dma_sg);
 	}
 }
 
@@ -606,7 +607,7 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
 	sgtmp = sglist;
 	while (used && sgtmp->dma_length) {
 		sgtmp->dma_address += dma_base;
-		sgtmp++;
+		sgtmp = sg_next(sgtmp);
 		used--;
 	}
 	used = nelems - used;
@@ -642,6 +643,7 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
 	struct strbuf *strbuf;
 	iopte_t *base;
 	unsigned long flags, ctx, i, npages;
+	struct scatterlist *sg, *sgprv;
 	u32 bus_addr;
 
 	if (unlikely(direction == DMA_NONE)) {
@@ -654,11 +656,14 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
 
 	bus_addr = sglist->dma_address & IO_PAGE_MASK;
 
-	for (i = 1; i < nelems; i++)
-		if (sglist[i].dma_length == 0)
+	sgprv = NULL;
+	for_each_sg(sglist, sg, nelems, i) {
+		if (sg->dma_length == 0)
 			break;
-	i--;
-	npages = (IO_PAGE_ALIGN(sglist[i].dma_address + sglist[i].dma_length) -
+		sgprv = sg;
+	}
+
+	npages = (IO_PAGE_ALIGN(sgprv->dma_address + sgprv->dma_length) -
 		  bus_addr) >> IO_PAGE_SHIFT;
 
 	base = iommu->page_table +
@@ -730,6 +735,7 @@ static void dma_4u_sync_sg_for_cpu(struct device *dev,
 	struct iommu *iommu;
 	struct strbuf *strbuf;
 	unsigned long flags, ctx, npages, i;
+	struct scatterlist *sg, *sgprv;
 	u32 bus_addr;
 
 	iommu = dev->archdata.iommu;
@@ -753,11 +759,14 @@ static void dma_4u_sync_sg_for_cpu(struct device *dev,
 
 	/* Step 2: Kick data out of streaming buffers. */
 	bus_addr = sglist[0].dma_address & IO_PAGE_MASK;
-	for(i = 1; i < nelems; i++)
-		if (!sglist[i].dma_length)
+	sgprv = NULL;
+	for_each_sg(sglist, sg, nelems, i) {
+		if (sg->dma_length == 0)
 			break;
-	i--;
-	npages = (IO_PAGE_ALIGN(sglist[i].dma_address + sglist[i].dma_length)
+		sgprv = sg;
+	}
+
+	npages = (IO_PAGE_ALIGN(sgprv->dma_address + sgprv->dma_length)
 		  - bus_addr) >> IO_PAGE_SHIFT;
 	strbuf_flush(strbuf, iommu, bus_addr, ctx, npages, direction);
 
diff --git a/arch/sparc64/kernel/pci_sun4v.c b/arch/sparc64/kernel/pci_sun4v.c
index 95de1444ee67..cacacfae5451 100644
--- a/arch/sparc64/kernel/pci_sun4v.c
+++ b/arch/sparc64/kernel/pci_sun4v.c
@@ -13,6 +13,7 @@
 #include <linux/irq.h>
 #include <linux/msi.h>
 #include <linux/log2.h>
+#include <linux/scatterlist.h>
 
 #include <asm/iommu.h>
 #include <asm/irq.h>
@@ -373,7 +374,7 @@ static inline long fill_sg(long entry, struct device *dev,
 			   int nused, int nelems, unsigned long prot)
 {
 	struct scatterlist *dma_sg = sg;
-	struct scatterlist *sg_end = sg + nelems;
+	struct scatterlist *sg_end = sg_last(sg, nelems);
 	unsigned long flags;
 	int i;
 
@@ -413,7 +414,7 @@ static inline long fill_sg(long entry, struct device *dev,
 					len -= (IO_PAGE_SIZE - (tmp & (IO_PAGE_SIZE - 1UL)));
 					break;
 				}
-				sg++;
+				sg = sg_next(sg);
 			}
 
 			pteval = (pteval & IOPTE_PAGE);
@@ -431,24 +432,25 @@ static inline long fill_sg(long entry, struct device *dev,
 			}
 
 			pteval = (pteval & IOPTE_PAGE) + len;
-			sg++;
+			sg = sg_next(sg);
 
 			/* Skip over any tail mappings we've fully mapped,
 			 * adjusting pteval along the way.  Stop when we
 			 * detect a page crossing event.
 			 */
-			while (sg < sg_end &&
-			       (pteval << (64 - IO_PAGE_SHIFT)) != 0UL &&
+			while ((pteval << (64 - IO_PAGE_SHIFT)) != 0UL &&
 			       (pteval == SG_ENT_PHYS_ADDRESS(sg)) &&
 			       ((pteval ^
 				 (SG_ENT_PHYS_ADDRESS(sg) + sg->length - 1UL)) >> IO_PAGE_SHIFT) == 0UL) {
 				pteval += sg->length;
-				sg++;
+				if (sg == sg_end)
+					break;
+				sg = sg_next(sg);
 			}
 			if ((pteval << (64 - IO_PAGE_SHIFT)) == 0UL)
 				pteval = ~0UL;
 		} while (dma_npages != 0);
-		dma_sg++;
+		dma_sg = sg_next(dma_sg);
 	}
 
 	if (unlikely(iommu_batch_end() < 0L))
@@ -510,7 +512,7 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
 	sgtmp = sglist;
 	while (used && sgtmp->dma_length) {
 		sgtmp->dma_address += dma_base;
-		sgtmp++;
+		sgtmp = sg_next(sgtmp);
 		used--;
 	}
 	used = nelems - used;
@@ -545,6 +547,7 @@ static void dma_4v_unmap_sg(struct device *dev, struct scatterlist *sglist,
 	struct pci_pbm_info *pbm;
 	struct iommu *iommu;
 	unsigned long flags, i, npages;
+	struct scatterlist *sg, *sgprv;
 	long entry;
 	u32 devhandle, bus_addr;
 
@@ -558,12 +561,15 @@ static void dma_4v_unmap_sg(struct device *dev, struct scatterlist *sglist,
 	devhandle = pbm->devhandle;
 	
 	bus_addr = sglist->dma_address & IO_PAGE_MASK;
-
-	for (i = 1; i < nelems; i++)
-		if (sglist[i].dma_length == 0)
+	sgprv = NULL;
+	for_each_sg(sglist, sg, nelems, i) {
+		if (sg->dma_length == 0)
 			break;
-	i--;
-	npages = (IO_PAGE_ALIGN(sglist[i].dma_address + sglist[i].dma_length) -
+
+		sgprv = sg;
+	}
+
+	npages = (IO_PAGE_ALIGN(sgprv->dma_address + sgprv->dma_length) -
 		  bus_addr) >> IO_PAGE_SHIFT;
 
 	entry = ((bus_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
diff --git a/arch/x86/kernel/pci-calgary_64.c b/arch/x86/kernel/pci-calgary_64.c
index 71da01e73f03..a50b787b3bfa 100644
--- a/arch/x86/kernel/pci-calgary_64.c
+++ b/arch/x86/kernel/pci-calgary_64.c
@@ -35,6 +35,7 @@
 #include <linux/pci_ids.h>
 #include <linux/pci.h>
 #include <linux/delay.h>
+#include <linux/scatterlist.h>
 #include <asm/iommu.h>
 #include <asm/calgary.h>
 #include <asm/tce.h>
@@ -384,31 +385,32 @@ static void calgary_unmap_sg(struct device *dev,
 	struct scatterlist *sglist, int nelems, int direction)
 {
 	struct iommu_table *tbl = find_iommu_table(dev);
+	struct scatterlist *s;
+	int i;
 
 	if (!translate_phb(to_pci_dev(dev)))
 		return;
 
-	while (nelems--) {
+	for_each_sg(sglist, s, nelems, i) {
 		unsigned int npages;
-		dma_addr_t dma = sglist->dma_address;
-		unsigned int dmalen = sglist->dma_length;
+		dma_addr_t dma = s->dma_address;
+		unsigned int dmalen = s->dma_length;
 
 		if (dmalen == 0)
 			break;
 
 		npages = num_dma_pages(dma, dmalen);
 		iommu_free(tbl, dma, npages);
-		sglist++;
 	}
 }
 
 static int calgary_nontranslate_map_sg(struct device* dev,
 	struct scatterlist *sg, int nelems, int direction)
 {
+	struct scatterlist *s;
 	int i;
 
-	for (i = 0; i < nelems; i++ ) {
-		struct scatterlist *s = &sg[i];
+	for_each_sg(sg, s, nelems, i) {
 		BUG_ON(!s->page);
 		s->dma_address = virt_to_bus(page_address(s->page) +s->offset);
 		s->dma_length = s->length;
@@ -420,6 +422,7 @@ static int calgary_map_sg(struct device *dev, struct scatterlist *sg,
 	int nelems, int direction)
 {
 	struct iommu_table *tbl = find_iommu_table(dev);
+	struct scatterlist *s;
 	unsigned long vaddr;
 	unsigned int npages;
 	unsigned long entry;
@@ -428,8 +431,7 @@ static int calgary_map_sg(struct device *dev, struct scatterlist *sg,
 	if (!translate_phb(to_pci_dev(dev)))
 		return calgary_nontranslate_map_sg(dev, sg, nelems, direction);
 
-	for (i = 0; i < nelems; i++ ) {
-		struct scatterlist *s = &sg[i];
+	for_each_sg(sg, s, nelems, i) {
 		BUG_ON(!s->page);
 
 		vaddr = (unsigned long)page_address(s->page) + s->offset;
@@ -454,9 +456,9 @@ static int calgary_map_sg(struct device *dev, struct scatterlist *sg,
 	return nelems;
 error:
 	calgary_unmap_sg(dev, sg, nelems, direction);
-	for (i = 0; i < nelems; i++) {
-		sg[i].dma_address = bad_dma_address;
-		sg[i].dma_length = 0;
+	for_each_sg(sg, s, nelems, i) {
+		sg->dma_address = bad_dma_address;
+		sg->dma_length = 0;
 	}
 	return 0;
 }
diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index 4918c575d582..cfcc84e6c350 100644
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -23,6 +23,7 @@
 #include <linux/interrupt.h>
 #include <linux/bitops.h>
 #include <linux/kdebug.h>
+#include <linux/scatterlist.h>
 #include <asm/atomic.h>
 #include <asm/io.h>
 #include <asm/mtrr.h>
@@ -278,10 +279,10 @@ static void gart_unmap_single(struct device *dev, dma_addr_t dma_addr,
  */
 static void gart_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
 {
+	struct scatterlist *s;
 	int i;
 
-	for (i = 0; i < nents; i++) {
-		struct scatterlist *s = &sg[i];
+	for_each_sg(sg, s, nents, i) {
 		if (!s->dma_length || !s->length)
 			break;
 		gart_unmap_single(dev, s->dma_address, s->dma_length, dir);
@@ -292,14 +293,14 @@ static void gart_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
 static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
 			       int nents, int dir)
 {
+	struct scatterlist *s;
 	int i;
 
 #ifdef CONFIG_IOMMU_DEBUG
 	printk(KERN_DEBUG "dma_map_sg overflow\n");
 #endif
 
- 	for (i = 0; i < nents; i++ ) {
-		struct scatterlist *s = &sg[i];
+	for_each_sg(sg, s, nents, i) {
 		unsigned long addr = page_to_phys(s->page) + s->offset; 
 		if (nonforced_iommu(dev, addr, s->length)) { 
 			addr = dma_map_area(dev, addr, s->length, dir);
@@ -319,23 +320,23 @@ static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
 }
 
 /* Map multiple scatterlist entries continuous into the first. */
-static int __dma_map_cont(struct scatterlist *sg, int start, int stopat,
+static int __dma_map_cont(struct scatterlist *start, int nelems,
 		      struct scatterlist *sout, unsigned long pages)
 {
 	unsigned long iommu_start = alloc_iommu(pages);
 	unsigned long iommu_page = iommu_start; 
+	struct scatterlist *s;
 	int i;
 
 	if (iommu_start == -1)
 		return -1;
-	
-	for (i = start; i < stopat; i++) {
-		struct scatterlist *s = &sg[i];
+
+	for_each_sg(start, s, nelems, i) {
 		unsigned long pages, addr;
 		unsigned long phys_addr = s->dma_address;
 		
-		BUG_ON(i > start && s->offset);
-		if (i == start) {
+		BUG_ON(s != start && s->offset);
+		if (s == start) {
 			*sout = *s; 
 			sout->dma_address = iommu_bus_base;
 			sout->dma_address += iommu_page*PAGE_SIZE + s->offset;
@@ -357,17 +358,17 @@ static int __dma_map_cont(struct scatterlist *sg, int start, int stopat,
 	return 0;
 }
 
-static inline int dma_map_cont(struct scatterlist *sg, int start, int stopat,
+static inline int dma_map_cont(struct scatterlist *start, int nelems,
 		      struct scatterlist *sout,
 		      unsigned long pages, int need)
 {
-	if (!need) { 
-		BUG_ON(stopat - start != 1);
-		*sout = sg[start]; 
-		sout->dma_length = sg[start].length; 
+	if (!need) {
+		BUG_ON(nelems != 1);
+		*sout = *start;
+		sout->dma_length = start->length;
 		return 0;
-	} 
-	return __dma_map_cont(sg, start, stopat, sout, pages);
+	}
+	return __dma_map_cont(start, nelems, sout, pages);
 }
 		
 /*
@@ -381,6 +382,7 @@ int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
 	int start;
 	unsigned long pages = 0;
 	int need = 0, nextneed;
+	struct scatterlist *s, *ps, *start_sg, *sgmap;
 
 	if (nents == 0) 
 		return 0;
@@ -390,8 +392,9 @@ int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
 
 	out = 0;
 	start = 0;
-	for (i = 0; i < nents; i++) {
-		struct scatterlist *s = &sg[i];
+	start_sg = sgmap = sg;
+	ps = NULL; /* shut up gcc */
+	for_each_sg(sg, s, nents, i) {
 		dma_addr_t addr = page_to_phys(s->page) + s->offset;
 		s->dma_address = addr;
 		BUG_ON(s->length == 0); 
@@ -400,29 +403,33 @@ int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
 
 		/* Handle the previous not yet processed entries */
 		if (i > start) {
-			struct scatterlist *ps = &sg[i-1];
 			/* Can only merge when the last chunk ends on a page 
 			   boundary and the new one doesn't have an offset. */
 			if (!iommu_merge || !nextneed || !need || s->offset ||
-			    (ps->offset + ps->length) % PAGE_SIZE) { 
-				if (dma_map_cont(sg, start, i, sg+out, pages,
-						 need) < 0)
+			    (ps->offset + ps->length) % PAGE_SIZE) {
+				if (dma_map_cont(start_sg, i - start, sgmap,
+						  pages, need) < 0)
 					goto error;
 				out++;
+				sgmap = sg_next(sgmap);
 				pages = 0;
-				start = i;	
+				start = i;
+				start_sg = s;
 			}
 		}
 
 		need = nextneed;
 		pages += to_pages(s->offset, s->length);
+		ps = s;
 	}
-	if (dma_map_cont(sg, start, i, sg+out, pages, need) < 0)
+	if (dma_map_cont(start_sg, i - start, sgmap, pages, need) < 0)
 		goto error;
 	out++;
 	flush_gart();
-	if (out < nents) 
-		sg[out].dma_length = 0; 
+	if (out < nents) {
+		sgmap = sg_next(sgmap);
+		sgmap->dma_length = 0;
+	}
 	return out;
 
 error:
@@ -437,8 +444,8 @@ error:
 	if (panic_on_overflow)
 		panic("dma_map_sg: overflow on %lu pages\n", pages);
 	iommu_full(dev, pages << PAGE_SHIFT, dir);
-	for (i = 0; i < nents; i++)
-		sg[i].dma_address = bad_dma_address;
+	for_each_sg(sg, s, nents, i)
+		s->dma_address = bad_dma_address;
 	return 0;
 } 
 
diff --git a/arch/x86/kernel/pci-nommu_64.c b/arch/x86/kernel/pci-nommu_64.c
index 2a34c6c025a9..e85d4360360c 100644
--- a/arch/x86/kernel/pci-nommu_64.c
+++ b/arch/x86/kernel/pci-nommu_64.c
@@ -5,6 +5,7 @@
 #include <linux/pci.h>
 #include <linux/string.h>
 #include <linux/dma-mapping.h>
+#include <linux/scatterlist.h>
 
 #include <asm/iommu.h>
 #include <asm/processor.h>
@@ -57,10 +58,10 @@ static void nommu_unmap_single(struct device *dev, dma_addr_t addr,size_t size,
 static int nommu_map_sg(struct device *hwdev, struct scatterlist *sg,
 	       int nents, int direction)
 {
+	struct scatterlist *s;
 	int i;
 
- 	for (i = 0; i < nents; i++ ) {
-		struct scatterlist *s = &sg[i];
+	for_each_sg(sg, s, nents, i) {
 		BUG_ON(!s->page);
 		s->dma_address = virt_to_bus(page_address(s->page) +s->offset);
 		if (!check_addr("map_sg", hwdev, s->dma_address, s->length))
diff --git a/block/bsg.c b/block/bsg.c
index b8ddfc66f210..8e181ab3afb9 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -908,7 +908,7 @@ static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	}
 }
 
-static struct file_operations bsg_fops = {
+static const struct file_operations bsg_fops = {
 	.read		=	bsg_read,
 	.write		=	bsg_write,
 	.poll		=	bsg_poll,
diff --git a/block/elevator.c b/block/elevator.c
index b9c518afe1f8..952aee04a68a 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -712,6 +712,14 @@ struct request *elv_next_request(struct request_queue *q)
 	int ret;
 
 	while ((rq = __elv_next_request(q)) != NULL) {
+		/*
+		 * Kill the empty barrier place holder, the driver must
+		 * not ever see it.
+		 */
+		if (blk_empty_barrier(rq)) {
+			end_queued_request(rq, 1);
+			continue;
+		}
 		if (!(rq->cmd_flags & REQ_STARTED)) {
 			/*
 			 * This is the first time the device driver
@@ -751,15 +759,8 @@ struct request *elv_next_request(struct request_queue *q)
 			rq = NULL;
 			break;
 		} else if (ret == BLKPREP_KILL) {
-			int nr_bytes = rq->hard_nr_sectors << 9;
-
-			if (!nr_bytes)
-				nr_bytes = rq->data_len;
-
-			blkdev_dequeue_request(rq);
 			rq->cmd_flags |= REQ_QUIET;
-			end_that_request_chunk(rq, 0, nr_bytes);
-			end_that_request_last(rq, 0);
+			end_queued_request(rq, 0);
 		} else {
 			printk(KERN_ERR "%s: bad return=%d\n", __FUNCTION__,
 								ret);
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index a83823fcd74f..9eabac95fbe0 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -30,6 +30,7 @@
 #include <linux/cpu.h>
 #include <linux/blktrace_api.h>
 #include <linux/fault-inject.h>
+#include <linux/scatterlist.h>
 
 /*
  * for max sense size
@@ -304,23 +305,6 @@ int blk_queue_ordered(struct request_queue *q, unsigned ordered,
 
 EXPORT_SYMBOL(blk_queue_ordered);
 
-/**
- * blk_queue_issue_flush_fn - set function for issuing a flush
- * @q:     the request queue
- * @iff:   the function to be called issuing the flush
- *
- * Description:
- *   If a driver supports issuing a flush command, the support is notified
- *   to the block layer by defining it through this call.
- *
- **/
-void blk_queue_issue_flush_fn(struct request_queue *q, issue_flush_fn *iff)
-{
-	q->issue_flush_fn = iff;
-}
-
-EXPORT_SYMBOL(blk_queue_issue_flush_fn);
-
 /*
  * Cache flushing for ordered writes handling
  */
@@ -377,10 +361,12 @@ void blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error)
 	/*
 	 * Okay, sequence complete.
 	 */
-	rq = q->orig_bar_rq;
-	uptodate = q->orderr ? q->orderr : 1;
+	uptodate = 1;
+	if (q->orderr)
+		uptodate = q->orderr;
 
 	q->ordseq = 0;
+	rq = q->orig_bar_rq;
 
 	end_that_request_first(rq, uptodate, rq->hard_nr_sectors);
 	end_that_request_last(rq, uptodate);
@@ -445,7 +431,8 @@ static inline struct request *start_ordered(struct request_queue *q,
 	rq_init(q, rq);
 	if (bio_data_dir(q->orig_bar_rq->bio) == WRITE)
 		rq->cmd_flags |= REQ_RW;
-	rq->cmd_flags |= q->ordered & QUEUE_ORDERED_FUA ? REQ_FUA : 0;
+	if (q->ordered & QUEUE_ORDERED_FUA)
+		rq->cmd_flags |= REQ_FUA;
 	rq->elevator_private = NULL;
 	rq->elevator_private2 = NULL;
 	init_request_from_bio(rq, q->orig_bar_rq->bio);
@@ -455,9 +442,12 @@ static inline struct request *start_ordered(struct request_queue *q,
 	 * Queue ordered sequence.  As we stack them at the head, we
 	 * need to queue in reverse order.  Note that we rely on that
 	 * no fs request uses ELEVATOR_INSERT_FRONT and thus no fs
-	 * request gets inbetween ordered sequence.
+	 * request gets inbetween ordered sequence. If this request is
+	 * an empty barrier, we don't need to do a postflush ever since
+	 * there will be no data written between the pre and post flush.
+	 * Hence a single flush will suffice.
 	 */
-	if (q->ordered & QUEUE_ORDERED_POSTFLUSH)
+	if ((q->ordered & QUEUE_ORDERED_POSTFLUSH) && !blk_empty_barrier(rq))
 		queue_flush(q, QUEUE_ORDERED_POSTFLUSH);
 	else
 		q->ordseq |= QUEUE_ORDSEQ_POSTFLUSH;
@@ -481,7 +471,7 @@ static inline struct request *start_ordered(struct request_queue *q,
 int blk_do_ordered(struct request_queue *q, struct request **rqp)
 {
 	struct request *rq = *rqp;
-	int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq);
+	const int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq);
 
 	if (!q->ordseq) {
 		if (!is_barrier)
@@ -1329,9 +1319,10 @@ static int blk_hw_contig_segment(struct request_queue *q, struct bio *bio,
  * must make sure sg can hold rq->nr_phys_segments entries
  */
 int blk_rq_map_sg(struct request_queue *q, struct request *rq,
-		  struct scatterlist *sg)
+		  struct scatterlist *sglist)
 {
 	struct bio_vec *bvec, *bvprv;
+	struct scatterlist *next_sg, *sg;
 	struct req_iterator iter;
 	int nsegs, cluster;
 
@@ -1342,11 +1333,12 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
 	 * for each bio in rq
 	 */
 	bvprv = NULL;
+	sg = next_sg = &sglist[0];
 	rq_for_each_segment(bvec, rq, iter) {
 		int nbytes = bvec->bv_len;
 
 		if (bvprv && cluster) {
-			if (sg[nsegs - 1].length + nbytes > q->max_segment_size)
+			if (sg->length + nbytes > q->max_segment_size)
 				goto new_segment;
 
 			if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec))
@@ -1354,14 +1346,15 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
 			if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec))
 				goto new_segment;
 
-			sg[nsegs - 1].length += nbytes;
+			sg->length += nbytes;
 		} else {
 new_segment:
-			memset(&sg[nsegs],0,sizeof(struct scatterlist));
-			sg[nsegs].page = bvec->bv_page;
-			sg[nsegs].length = nbytes;
-			sg[nsegs].offset = bvec->bv_offset;
+			sg = next_sg;
+			next_sg = sg_next(sg);
 
+			sg->page = bvec->bv_page;
+			sg->length = nbytes;
+			sg->offset = bvec->bv_offset;
 			nsegs++;
 		}
 		bvprv = bvec;
@@ -2660,6 +2653,14 @@ int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
 
 EXPORT_SYMBOL(blk_execute_rq);
 
+static void bio_end_empty_barrier(struct bio *bio, int err)
+{
+	if (err)
+		clear_bit(BIO_UPTODATE, &bio->bi_flags);
+
+	complete(bio->bi_private);
+}
+
 /**
  * blkdev_issue_flush - queue a flush
  * @bdev:	blockdev to issue flush for
@@ -2672,7 +2673,10 @@ EXPORT_SYMBOL(blk_execute_rq);
  */
 int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
 {
+	DECLARE_COMPLETION_ONSTACK(wait);
 	struct request_queue *q;
+	struct bio *bio;
+	int ret;
 
 	if (bdev->bd_disk == NULL)
 		return -ENXIO;
@@ -2680,10 +2684,32 @@ int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
 	q = bdev_get_queue(bdev);
 	if (!q)
 		return -ENXIO;
-	if (!q->issue_flush_fn)
-		return -EOPNOTSUPP;
 
-	return q->issue_flush_fn(q, bdev->bd_disk, error_sector);
+	bio = bio_alloc(GFP_KERNEL, 0);
+	if (!bio)
+		return -ENOMEM;
+
+	bio->bi_end_io = bio_end_empty_barrier;
+	bio->bi_private = &wait;
+	bio->bi_bdev = bdev;
+	submit_bio(1 << BIO_RW_BARRIER, bio);
+
+	wait_for_completion(&wait);
+
+	/*
+	 * The driver must store the error location in ->bi_sector, if
+	 * it supports it. For non-stacked drivers, this should be copied
+	 * from rq->sector.
+	 */
+	if (error_sector)
+		*error_sector = bio->bi_sector;
+
+	ret = 0;
+	if (!bio_flagged(bio, BIO_UPTODATE))
+		ret = -EIO;
+
+	bio_put(bio);
+	return ret;
 }
 
 EXPORT_SYMBOL(blkdev_issue_flush);
@@ -3051,7 +3077,7 @@ static inline void blk_partition_remap(struct bio *bio)
 {
 	struct block_device *bdev = bio->bi_bdev;
 
-	if (bdev != bdev->bd_contains) {
+	if (bio_sectors(bio) && bdev != bdev->bd_contains) {
 		struct hd_struct *p = bdev->bd_part;
 		const int rw = bio_data_dir(bio);
 
@@ -3117,6 +3143,35 @@ static inline int should_fail_request(struct bio *bio)
 
 #endif /* CONFIG_FAIL_MAKE_REQUEST */
 
+/*
+ * Check whether this bio extends beyond the end of the device.
+ */
+static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
+{
+	sector_t maxsector;
+
+	if (!nr_sectors)
+		return 0;
+
+	/* Test device or partition size, when known. */
+	maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
+	if (maxsector) {
+		sector_t sector = bio->bi_sector;
+
+		if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
+			/*
+			 * This may well happen - the kernel calls bread()
+			 * without checking the size of the device, e.g., when
+			 * mounting a device.
+			 */
+			handle_bad_sector(bio);
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
 /**
  * generic_make_request: hand a buffer to its device driver for I/O
  * @bio:  The bio describing the location in memory and on the device.
@@ -3144,27 +3199,14 @@ static inline int should_fail_request(struct bio *bio)
 static inline void __generic_make_request(struct bio *bio)
 {
 	struct request_queue *q;
-	sector_t maxsector;
 	sector_t old_sector;
 	int ret, nr_sectors = bio_sectors(bio);
 	dev_t old_dev;
 
 	might_sleep();
-	/* Test device or partition size, when known. */
-	maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
-	if (maxsector) {
-		sector_t sector = bio->bi_sector;
 
-		if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
-			/*
-			 * This may well happen - the kernel calls bread()
-			 * without checking the size of the device, e.g., when
-			 * mounting a device.
-			 */
-			handle_bad_sector(bio);
-			goto end_io;
-		}
-	}
+	if (bio_check_eod(bio, nr_sectors))
+		goto end_io;
 
 	/*
 	 * Resolve the mapping until finished. (drivers are
@@ -3191,7 +3233,7 @@ end_io:
 			break;
 		}
 
-		if (unlikely(bio_sectors(bio) > q->max_hw_sectors)) {
+		if (unlikely(nr_sectors > q->max_hw_sectors)) {
 			printk("bio too big device %s (%u > %u)\n", 
 				bdevname(bio->bi_bdev, b),
 				bio_sectors(bio),
@@ -3212,7 +3254,7 @@ end_io:
 		blk_partition_remap(bio);
 
 		if (old_sector != -1)
-			blk_add_trace_remap(q, bio, old_dev, bio->bi_sector, 
+			blk_add_trace_remap(q, bio, old_dev, bio->bi_sector,
 					    old_sector);
 
 		blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
@@ -3220,21 +3262,8 @@ end_io:
 		old_sector = bio->bi_sector;
 		old_dev = bio->bi_bdev->bd_dev;
 
-		maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
-		if (maxsector) {
-			sector_t sector = bio->bi_sector;
-
-			if (maxsector < nr_sectors ||
-					maxsector - nr_sectors < sector) {
-				/*
-				 * This may well happen - partitions are not
-				 * checked to make sure they are within the size
-				 * of the whole device.
-				 */
-				handle_bad_sector(bio);
-				goto end_io;
-			}
-		}
+		if (bio_check_eod(bio, nr_sectors))
+			goto end_io;
 
 		ret = q->make_request_fn(q, bio);
 	} while (ret);
@@ -3307,23 +3336,32 @@ void submit_bio(int rw, struct bio *bio)
 {
 	int count = bio_sectors(bio);
 
-	BIO_BUG_ON(!bio->bi_size);
-	BIO_BUG_ON(!bio->bi_io_vec);
 	bio->bi_rw |= rw;
-	if (rw & WRITE) {
-		count_vm_events(PGPGOUT, count);
-	} else {
-		task_io_account_read(bio->bi_size);
-		count_vm_events(PGPGIN, count);
-	}
 
-	if (unlikely(block_dump)) {
-		char b[BDEVNAME_SIZE];
-		printk(KERN_DEBUG "%s(%d): %s block %Lu on %s\n",
-			current->comm, current->pid,
-			(rw & WRITE) ? "WRITE" : "READ",
-			(unsigned long long)bio->bi_sector,
-			bdevname(bio->bi_bdev,b));
+	/*
+	 * If it's a regular read/write or a barrier with data attached,
+	 * go through the normal accounting stuff before submission.
+	 */
+	if (!bio_empty_barrier(bio)) {
+
+		BIO_BUG_ON(!bio->bi_size);
+		BIO_BUG_ON(!bio->bi_io_vec);
+
+		if (rw & WRITE) {
+			count_vm_events(PGPGOUT, count);
+		} else {
+			task_io_account_read(bio->bi_size);
+			count_vm_events(PGPGIN, count);
+		}
+
+		if (unlikely(block_dump)) {
+			char b[BDEVNAME_SIZE];
+			printk(KERN_DEBUG "%s(%d): %s block %Lu on %s\n",
+				current->comm, current->pid,
+				(rw & WRITE) ? "WRITE" : "READ",
+				(unsigned long long)bio->bi_sector,
+				bdevname(bio->bi_bdev,b));
+		}
 	}
 
 	generic_make_request(bio);
@@ -3399,6 +3437,14 @@ static int __end_that_request_first(struct request *req, int uptodate,
 	while ((bio = req->bio) != NULL) {
 		int nbytes;
 
+		/*
+		 * For an empty barrier request, the low level driver must
+		 * store a potential error location in ->sector. We pass
+		 * that back up in ->bi_sector.
+		 */
+		if (blk_empty_barrier(req))
+			bio->bi_sector = req->sector;
+
 		if (nr_bytes >= bio->bi_size) {
 			req->bio = bio->bi_next;
 			nbytes = bio->bi_size;
@@ -3564,7 +3610,7 @@ static struct notifier_block blk_cpu_notifier __cpuinitdata = {
  * Description:
  *     Ends all I/O on a request. It does not handle partial completions,
  *     unless the driver actually implements this in its completion callback
- *     through requeueing. Theh actual completion happens out-of-order,
+ *     through requeueing. The actual completion happens out-of-order,
  *     through a softirq handler. The user must have registered a completion
  *     callback through blk_queue_softirq_done().
  **/
@@ -3627,15 +3673,83 @@ void end_that_request_last(struct request *req, int uptodate)
 
 EXPORT_SYMBOL(end_that_request_last);
 
-void end_request(struct request *req, int uptodate)
+static inline void __end_request(struct request *rq, int uptodate,
+				 unsigned int nr_bytes, int dequeue)
 {
-	if (!end_that_request_first(req, uptodate, req->hard_cur_sectors)) {
-		add_disk_randomness(req->rq_disk);
-		blkdev_dequeue_request(req);
-		end_that_request_last(req, uptodate);
+	if (!end_that_request_chunk(rq, uptodate, nr_bytes)) {
+		if (dequeue)
+			blkdev_dequeue_request(rq);
+		add_disk_randomness(rq->rq_disk);
+		end_that_request_last(rq, uptodate);
 	}
 }
 
+static unsigned int rq_byte_size(struct request *rq)
+{
+	if (blk_fs_request(rq))
+		return rq->hard_nr_sectors << 9;
+
+	return rq->data_len;
+}
+
+/**
+ * end_queued_request - end all I/O on a queued request
+ * @rq:		the request being processed
+ * @uptodate:	error value or 0/1 uptodate flag
+ *
+ * Description:
+ *     Ends all I/O on a request, and removes it from the block layer queues.
+ *     Not suitable for normal IO completion, unless the driver still has
+ *     the request attached to the block layer.
+ *
+ **/
+void end_queued_request(struct request *rq, int uptodate)
+{
+	__end_request(rq, uptodate, rq_byte_size(rq), 1);
+}
+EXPORT_SYMBOL(end_queued_request);
+
+/**
+ * end_dequeued_request - end all I/O on a dequeued request
+ * @rq:		the request being processed
+ * @uptodate:	error value or 0/1 uptodate flag
+ *
+ * Description:
+ *     Ends all I/O on a request. The request must already have been
+ *     dequeued using blkdev_dequeue_request(), as is normally the case
+ *     for most drivers.
+ *
+ **/
+void end_dequeued_request(struct request *rq, int uptodate)
+{
+	__end_request(rq, uptodate, rq_byte_size(rq), 0);
+}
+EXPORT_SYMBOL(end_dequeued_request);
+
+
+/**
+ * end_request - end I/O on the current segment of the request
+ * @rq:		the request being processed
+ * @uptodate:	error value or 0/1 uptodate flag
+ *
+ * Description:
+ *     Ends I/O on the current segment of a request. If that is the only
+ *     remaining segment, the request is also completed and freed.
+ *
+ *     This is a remnant of how older block drivers handled IO completions.
+ *     Modern drivers typically end IO on the full request in one go, unless
+ *     they have a residual value to account for. For that case this function
+ *     isn't really useful, unless the residual just happens to be the
+ *     full current segment. In other words, don't use this function in new
+ *     code. Either use end_request_completely(), or the
+ *     end_that_request_chunk() (along with end_that_request_last()) for
+ *     partial completions.
+ *
+ **/
+void end_request(struct request *req, int uptodate)
+{
+	__end_request(req, uptodate, req->hard_cur_sectors << 9, 1);
+}
 EXPORT_SYMBOL(end_request);
 
 static void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
@@ -3949,7 +4063,23 @@ static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 	return queue_var_show(max_hw_sectors_kb, (page));
 }
 
+static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(q->max_phys_segments, page);
+}
+
+static ssize_t queue_max_segments_store(struct request_queue *q,
+					const char *page, size_t count)
+{
+	unsigned long segments;
+	ssize_t ret = queue_var_store(&segments, page, count);
+
+	spin_lock_irq(q->queue_lock);
+	q->max_phys_segments = segments;
+	spin_unlock_irq(q->queue_lock);
 
+	return ret;
+}
 static struct queue_sysfs_entry queue_requests_entry = {
 	.attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 	.show = queue_requests_show,
@@ -3973,6 +4103,12 @@ static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 	.show = queue_max_hw_sectors_show,
 };
 
+static struct queue_sysfs_entry queue_max_segments_entry = {
+	.attr = {.name = "max_segments", .mode = S_IRUGO | S_IWUSR },
+	.show = queue_max_segments_show,
+	.store = queue_max_segments_store,
+};
+
 static struct queue_sysfs_entry queue_iosched_entry = {
 	.attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 	.show = elv_iosched_show,
@@ -3984,6 +4120,7 @@ static struct attribute *default_attrs[] = {
 	&queue_ra_entry.attr,
 	&queue_max_hw_sectors_entry.attr,
 	&queue_max_sectors_entry.attr,
+	&queue_max_segments_entry.attr,
 	&queue_iosched_entry.attr,
 	NULL,
 };
diff --git a/crypto/digest.c b/crypto/digest.c
index 1bf7414aeb9e..e56de6748b15 100644
--- a/crypto/digest.c
+++ b/crypto/digest.c
@@ -77,7 +77,7 @@ static int update2(struct hash_desc *desc,
 
 		if (!nbytes)
 			break;
-		sg = sg_next(sg);
+		sg = scatterwalk_sg_next(sg);
 	}
 
 	return 0;
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 3052f6507f53..d6852c33cfb7 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -62,7 +62,7 @@ static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
 		walk->offset += PAGE_SIZE - 1;
 		walk->offset &= PAGE_MASK;
 		if (walk->offset >= walk->sg->offset + walk->sg->length)
-			scatterwalk_start(walk, sg_next(walk->sg));
+			scatterwalk_start(walk, scatterwalk_sg_next(walk->sg));
 	}
 }
 
diff --git a/crypto/scatterwalk.h b/crypto/scatterwalk.h
index 500a220ad908..9c73e37a42ce 100644
--- a/crypto/scatterwalk.h
+++ b/crypto/scatterwalk.h
@@ -20,7 +20,7 @@
 
 #include "internal.h"
 
-static inline struct scatterlist *sg_next(struct scatterlist *sg)
+static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
 {
 	return (++sg)->length ? sg : (void *)sg->page;
 }
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 68699b3e7998..bbaa545ea999 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1410,7 +1410,7 @@ static void ata_qc_complete_internal(struct ata_queued_cmd *qc)
  */
 unsigned ata_exec_internal_sg(struct ata_device *dev,
 			      struct ata_taskfile *tf, const u8 *cdb,
-			      int dma_dir, struct scatterlist *sg,
+			      int dma_dir, struct scatterlist *sgl,
 			      unsigned int n_elem, unsigned long timeout)
 {
 	struct ata_link *link = dev->link;
@@ -1472,11 +1472,12 @@ unsigned ata_exec_internal_sg(struct ata_device *dev,
 	qc->dma_dir = dma_dir;
 	if (dma_dir != DMA_NONE) {
 		unsigned int i, buflen = 0;
+		struct scatterlist *sg;
 
-		for (i = 0; i < n_elem; i++)
-			buflen += sg[i].length;
+		for_each_sg(sgl, sg, n_elem, i)
+			buflen += sg->length;
 
-		ata_sg_init(qc, sg, n_elem);
+		ata_sg_init(qc, sgl, n_elem);
 		qc->nbytes = buflen;
 	}
 
@@ -4292,7 +4293,7 @@ void ata_sg_clean(struct ata_queued_cmd *qc)
 		if (qc->n_elem)
 			dma_unmap_sg(ap->dev, sg, qc->n_elem, dir);
 		/* restore last sg */
-		sg[qc->orig_n_elem - 1].length += qc->pad_len;
+		sg_last(sg, qc->orig_n_elem)->length += qc->pad_len;
 		if (pad_buf) {
 			struct scatterlist *psg = &qc->pad_sgent;
 			void *addr = kmap_atomic(psg->page, KM_IRQ0);
@@ -4547,6 +4548,7 @@ void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf, unsigned int buflen)
 	qc->orig_n_elem = 1;
 	qc->buf_virt = buf;
 	qc->nbytes = buflen;
+	qc->cursg = qc->__sg;
 
 	sg_init_one(&qc->sgent, buf, buflen);
 }
@@ -4572,6 +4574,7 @@ void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
 	qc->__sg = sg;
 	qc->n_elem = n_elem;
 	qc->orig_n_elem = n_elem;
+	qc->cursg = qc->__sg;
 }
 
 /**
@@ -4661,7 +4664,7 @@ static int ata_sg_setup(struct ata_queued_cmd *qc)
 {
 	struct ata_port *ap = qc->ap;
 	struct scatterlist *sg = qc->__sg;
-	struct scatterlist *lsg = &sg[qc->n_elem - 1];
+	struct scatterlist *lsg = sg_last(qc->__sg, qc->n_elem);
 	int n_elem, pre_n_elem, dir, trim_sg = 0;
 
 	VPRINTK("ENTER, ata%u\n", ap->print_id);
@@ -4825,7 +4828,6 @@ void ata_data_xfer_noirq(struct ata_device *adev, unsigned char *buf,
 static void ata_pio_sector(struct ata_queued_cmd *qc)
 {
 	int do_write = (qc->tf.flags & ATA_TFLAG_WRITE);
-	struct scatterlist *sg = qc->__sg;
 	struct ata_port *ap = qc->ap;
 	struct page *page;
 	unsigned int offset;
@@ -4834,8 +4836,8 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
 	if (qc->curbytes == qc->nbytes - qc->sect_size)
 		ap->hsm_task_state = HSM_ST_LAST;
 
-	page = sg[qc->cursg].page;
-	offset = sg[qc->cursg].offset + qc->cursg_ofs;
+	page = qc->cursg->page;
+	offset = qc->cursg->offset + qc->cursg_ofs;
 
 	/* get the current page and offset */
 	page = nth_page(page, (offset >> PAGE_SHIFT));
@@ -4863,8 +4865,8 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
 	qc->curbytes += qc->sect_size;
 	qc->cursg_ofs += qc->sect_size;
 
-	if (qc->cursg_ofs == (&sg[qc->cursg])->length) {
-		qc->cursg++;
+	if (qc->cursg_ofs == qc->cursg->length) {
+		qc->cursg = sg_next(qc->cursg);
 		qc->cursg_ofs = 0;
 	}
 }
@@ -4950,16 +4952,18 @@ static void __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes)
 {
 	int do_write = (qc->tf.flags & ATA_TFLAG_WRITE);
 	struct scatterlist *sg = qc->__sg;
+	struct scatterlist *lsg = sg_last(qc->__sg, qc->n_elem);
 	struct ata_port *ap = qc->ap;
 	struct page *page;
 	unsigned char *buf;
 	unsigned int offset, count;
+	int no_more_sg = 0;
 
 	if (qc->curbytes + bytes >= qc->nbytes)
 		ap->hsm_task_state = HSM_ST_LAST;
 
 next_sg:
-	if (unlikely(qc->cursg >= qc->n_elem)) {
+	if (unlikely(no_more_sg)) {
 		/*
 		 * The end of qc->sg is reached and the device expects
 		 * more data to transfer. In order not to overrun qc->sg
@@ -4982,7 +4986,7 @@ next_sg:
 		return;
 	}
 
-	sg = &qc->__sg[qc->cursg];
+	sg = qc->cursg;
 
 	page = sg->page;
 	offset = sg->offset + qc->cursg_ofs;
@@ -5021,7 +5025,10 @@ next_sg:
 	qc->cursg_ofs += count;
 
 	if (qc->cursg_ofs == sg->length) {
-		qc->cursg++;
+		if (qc->cursg == lsg)
+			no_more_sg = 1;
+
+		qc->cursg = sg_next(qc->cursg);
 		qc->cursg_ofs = 0;
 	}
 
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 5237a491622b..9fbb39cd0f58 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -801,8 +801,6 @@ int ata_scsi_slave_config(struct scsi_device *sdev)
 
 	ata_scsi_sdev_config(sdev);
 
-	blk_queue_max_phys_segments(sdev->request_queue, LIBATA_MAX_PRD);
-
 	sdev->manage_start_stop = 1;
 
 	if (dev)
diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 55c3237fb1bc..3fb7e8bc436d 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -1191,7 +1191,6 @@ static inline void complete_buffers(struct bio *bio, int status)
 {
 	while (bio) {
 		struct bio *xbh = bio->bi_next;
-		int nr_sectors = bio_sectors(bio);
 
 		bio->bi_next = NULL;
 		bio_endio(bio, status ? 0 : -EIO);
@@ -2570,6 +2569,7 @@ static void do_cciss_request(struct request_queue *q)
 	       (int)creq->nr_sectors);
 #endif				/* CCISS_DEBUG */
 
+	memset(tmp_sg, 0, sizeof(tmp_sg));
 	seg = blk_rq_map_sg(q, creq, tmp_sg);
 
 	/* get the DMA records for the setup */
diff --git a/drivers/block/cpqarray.c b/drivers/block/cpqarray.c
index 3853c9a38d6a..568603d3043e 100644
--- a/drivers/block/cpqarray.c
+++ b/drivers/block/cpqarray.c
@@ -981,9 +981,8 @@ static void start_io(ctlr_info_t *h)
 static inline void complete_buffers(struct bio *bio, int ok)
 {
 	struct bio *xbh;
-	while(bio) {
-		int nr_sectors = bio_sectors(bio);
 
+	while (bio) {
 		xbh = bio->bi_next;
 		bio->bi_next = NULL;
 		
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 540bf3676985..a8130a4ad6d4 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -1133,16 +1133,21 @@ static void pkt_gather_data(struct pktcdvd_device *pd, struct packet_data *pkt)
 	 * Schedule reads for missing parts of the packet.
 	 */
 	for (f = 0; f < pkt->frames; f++) {
+		struct bio_vec *vec;
+
 		int p, offset;
 		if (written[f])
 			continue;
 		bio = pkt->r_bios[f];
+		vec = bio->bi_io_vec;
 		bio_init(bio);
 		bio->bi_max_vecs = 1;
 		bio->bi_sector = pkt->sector + f * (CD_FRAMESIZE >> 9);
 		bio->bi_bdev = pd->bdev;
 		bio->bi_end_io = pkt_end_io_read;
 		bio->bi_private = pkt;
+		bio->bi_io_vec = vec;
+		bio->bi_destructor = pkt_bio_destructor;
 
 		p = (f * CD_FRAMESIZE) / PAGE_SIZE;
 		offset = (f * CD_FRAMESIZE) % PAGE_SIZE;
@@ -1439,6 +1444,8 @@ static void pkt_start_write(struct pktcdvd_device *pd, struct packet_data *pkt)
 	pkt->w_bio->bi_bdev = pd->bdev;
 	pkt->w_bio->bi_end_io = pkt_end_io_packet_write;
 	pkt->w_bio->bi_private = pkt;
+	pkt->w_bio->bi_io_vec = bvec;
+	pkt->w_bio->bi_destructor = pkt_bio_destructor;
 	for (f = 0; f < pkt->frames; f++)
 		if (!bio_add_page(pkt->w_bio, bvec[f].bv_page, CD_FRAMESIZE, bvec[f].bv_offset))
 			BUG();
diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c
index 06d0552cf49c..e354bfc070e1 100644
--- a/drivers/block/ps3disk.c
+++ b/drivers/block/ps3disk.c
@@ -414,26 +414,6 @@ static void ps3disk_prepare_flush(struct request_queue *q, struct request *req)
 	req->cmd_type = REQ_TYPE_FLUSH;
 }
 
-static int ps3disk_issue_flush(struct request_queue *q, struct gendisk *gendisk,
-			       sector_t *sector)
-{
-	struct ps3_storage_device *dev = q->queuedata;
-	struct request *req;
-	int res;
-
-	dev_dbg(&dev->sbd.core, "%s:%u\n", __func__, __LINE__);
-
-	req = blk_get_request(q, WRITE, __GFP_WAIT);
-	ps3disk_prepare_flush(q, req);
-	res = blk_execute_rq(q, gendisk, req, 0);
-	if (res)
-		dev_err(&dev->sbd.core, "%s:%u: flush request failed %d\n",
-			__func__, __LINE__, res);
-	blk_put_request(req);
-	return res;
-}
-
-
 static unsigned long ps3disk_mask;
 
 static DEFINE_MUTEX(ps3disk_mask_mutex);
@@ -506,7 +486,6 @@ static int __devinit ps3disk_probe(struct ps3_system_bus_device *_dev)
 	blk_queue_dma_alignment(queue, dev->blk_size-1);
 	blk_queue_hardsect_size(queue, dev->blk_size);
 
-	blk_queue_issue_flush_fn(queue, ps3disk_issue_flush);
 	blk_queue_ordered(queue, QUEUE_ORDERED_DRAIN_FLUSH,
 			  ps3disk_prepare_flush);
 
diff --git a/drivers/ide/cris/ide-cris.c b/drivers/ide/cris/ide-cris.c
index 2b4d2a0ae5c2..c306c9f534ab 100644
--- a/drivers/ide/cris/ide-cris.c
+++ b/drivers/ide/cris/ide-cris.c
@@ -939,7 +939,8 @@ static int cris_ide_build_dmatable (ide_drive_t *drive)
 		/* group sequential buffers into one large buffer */
 		addr = page_to_phys(sg->page) + sg->offset;
 		size = sg_dma_len(sg);
-		while (sg++, --i) {
+		while (--i) {
+			sg = sg_next(sg);
 			if ((addr + size) != page_to_phys(sg->page) + sg->offset)
 				break;
 			size += sg_dma_len(sg);
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index 4754769eda97..92177ca48b4d 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -716,32 +716,6 @@ static void idedisk_prepare_flush(struct request_queue *q, struct request *rq)
 	rq->buffer = rq->cmd;
 }
 
-static int idedisk_issue_flush(struct request_queue *q, struct gendisk *disk,
-			       sector_t *error_sector)
-{
-	ide_drive_t *drive = q->queuedata;
-	struct request *rq;
-	int ret;
-
-	if (!drive->wcache)
-		return 0;
-
-	rq = blk_get_request(q, WRITE, __GFP_WAIT);
-
-	idedisk_prepare_flush(q, rq);
-
-	ret = blk_execute_rq(q, disk, rq, 0);
-
-	/*
-	 * if we failed and caller wants error offset, get it
-	 */
-	if (ret && error_sector)
-		*error_sector = ide_get_error_location(drive, rq->cmd);
-
-	blk_put_request(rq);
-	return ret;
-}
-
 /*
  * This is tightly woven into the driver->do_special can not touch.
  * DON'T do it again until a total personality rewrite is committed.
@@ -781,7 +755,6 @@ static void update_ordered(ide_drive_t *drive)
 	struct hd_driveid *id = drive->id;
 	unsigned ordered = QUEUE_ORDERED_NONE;
 	prepare_flush_fn *prep_fn = NULL;
-	issue_flush_fn *issue_fn = NULL;
 
 	if (drive->wcache) {
 		unsigned long long capacity;
@@ -805,13 +778,11 @@ static void update_ordered(ide_drive_t *drive)
 		if (barrier) {
 			ordered = QUEUE_ORDERED_DRAIN_FLUSH;
 			prep_fn = idedisk_prepare_flush;
-			issue_fn = idedisk_issue_flush;
 		}
 	} else
 		ordered = QUEUE_ORDERED_DRAIN;
 
 	blk_queue_ordered(drive->queue, ordered, prep_fn);
-	blk_queue_issue_flush_fn(drive->queue, issue_fn);
 }
 
 static int write_cache(ide_drive_t *drive, int arg)
diff --git a/drivers/ide/ide-dma.c b/drivers/ide/ide-dma.c
index b453211ee0fc..a4cbbbaccde9 100644
--- a/drivers/ide/ide-dma.c
+++ b/drivers/ide/ide-dma.c
@@ -280,7 +280,7 @@ int ide_build_dmatable (ide_drive_t *drive, struct request *rq)
 			}
 		}
 
-		sg++;
+		sg = sg_next(sg);
 		i--;
 	}
 
diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
index 4cece930114c..04273d3c147c 100644
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -322,41 +322,6 @@ static void ide_complete_pm_request (ide_drive_t *drive, struct request *rq)
 	spin_unlock_irqrestore(&ide_lock, flags);
 }
 
-/*
- * FIXME: probably move this somewhere else, name is bad too :)
- */
-u64 ide_get_error_location(ide_drive_t *drive, char *args)
-{
-	u32 high, low;
-	u8 hcyl, lcyl, sect;
-	u64 sector;
-
-	high = 0;
-	hcyl = args[5];
-	lcyl = args[4];
-	sect = args[3];
-
-	if (ide_id_has_flush_cache_ext(drive->id)) {
-		low = (hcyl << 16) | (lcyl << 8) | sect;
-		HWIF(drive)->OUTB(drive->ctl|0x80, IDE_CONTROL_REG);
-		high = ide_read_24(drive);
-	} else {
-		u8 cur = HWIF(drive)->INB(IDE_SELECT_REG);
-		if (cur & 0x40) {
-			high = cur & 0xf;
-			low = (hcyl << 16) | (lcyl << 8) | sect;
-		} else {
-			low = hcyl * drive->head * drive->sect;
-			low += lcyl * drive->sect;
-			low += sect - 1;
-		}
-	}
-
-	sector = ((u64) high << 24) | low;
-	return sector;
-}
-EXPORT_SYMBOL(ide_get_error_location);
-
 /**
  *	ide_end_drive_cmd	-	end an explicit drive command
  *	@drive: command 
@@ -881,7 +846,8 @@ void ide_init_sg_cmd(ide_drive_t *drive, struct request *rq)
 	ide_hwif_t *hwif = drive->hwif;
 
 	hwif->nsect = hwif->nleft = rq->nr_sectors;
-	hwif->cursg = hwif->cursg_ofs = 0;
+	hwif->cursg_ofs = 0;
+	hwif->cursg = NULL;
 }
 
 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
diff --git a/drivers/ide/ide-probe.c b/drivers/ide/ide-probe.c
index d1011712601c..34b1fb65bc79 100644
--- a/drivers/ide/ide-probe.c
+++ b/drivers/ide/ide-probe.c
@@ -1349,7 +1349,7 @@ static int hwif_init(ide_hwif_t *hwif)
 	if (!hwif->sg_max_nents)
 		hwif->sg_max_nents = PRD_ENTRIES;
 
-	hwif->sg_table = kmalloc(sizeof(struct scatterlist)*hwif->sg_max_nents,
+	hwif->sg_table = kzalloc(sizeof(struct scatterlist)*hwif->sg_max_nents,
 				 GFP_KERNEL);
 	if (!hwif->sg_table) {
 		printk(KERN_ERR "%s: unable to allocate SG table.\n", hwif->name);
diff --git a/drivers/ide/ide-taskfile.c b/drivers/ide/ide-taskfile.c
index aa06dafb74ac..2a3c8d498343 100644
--- a/drivers/ide/ide-taskfile.c
+++ b/drivers/ide/ide-taskfile.c
@@ -45,6 +45,7 @@
 #include <linux/hdreg.h>
 #include <linux/ide.h>
 #include <linux/bitops.h>
+#include <linux/scatterlist.h>
 
 #include <asm/byteorder.h>
 #include <asm/irq.h>
@@ -263,6 +264,7 @@ static void ide_pio_sector(ide_drive_t *drive, unsigned int write)
 {
 	ide_hwif_t *hwif = drive->hwif;
 	struct scatterlist *sg = hwif->sg_table;
+	struct scatterlist *cursg = hwif->cursg;
 	struct page *page;
 #ifdef CONFIG_HIGHMEM
 	unsigned long flags;
@@ -270,8 +272,14 @@ static void ide_pio_sector(ide_drive_t *drive, unsigned int write)
 	unsigned int offset;
 	u8 *buf;
 
-	page = sg[hwif->cursg].page;
-	offset = sg[hwif->cursg].offset + hwif->cursg_ofs * SECTOR_SIZE;
+	cursg = hwif->cursg;
+	if (!cursg) {
+		cursg = sg;
+		hwif->cursg = sg;
+	}
+
+	page = cursg->page;
+	offset = cursg->offset + hwif->cursg_ofs * SECTOR_SIZE;
 
 	/* get the current page and offset */
 	page = nth_page(page, (offset >> PAGE_SHIFT));
@@ -285,8 +293,8 @@ static void ide_pio_sector(ide_drive_t *drive, unsigned int write)
 	hwif->nleft--;
 	hwif->cursg_ofs++;
 
-	if ((hwif->cursg_ofs * SECTOR_SIZE) == sg[hwif->cursg].length) {
-		hwif->cursg++;
+	if ((hwif->cursg_ofs * SECTOR_SIZE) == cursg->length) {
+		hwif->cursg = sg_next(hwif->cursg);
 		hwif->cursg_ofs = 0;
 	}
 
@@ -367,6 +375,8 @@ static ide_startstop_t task_error(ide_drive_t *drive, struct request *rq,
 
 static void task_end_request(ide_drive_t *drive, struct request *rq, u8 stat)
 {
+	HWIF(drive)->cursg = NULL;
+
 	if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
 		ide_task_t *task = rq->special;
 
diff --git a/drivers/ide/mips/au1xxx-ide.c b/drivers/ide/mips/au1xxx-ide.c
index aebde49365d1..892d08f61dc0 100644
--- a/drivers/ide/mips/au1xxx-ide.c
+++ b/drivers/ide/mips/au1xxx-ide.c
@@ -296,7 +296,7 @@ static int auide_build_dmatable(ide_drive_t *drive)
 			cur_addr += tc;
 			cur_len -= tc;
 		}
-		sg++;
+		sg = sg_next(sg);
 		i--;
 	}
 
diff --git a/drivers/ide/pci/sgiioc4.c b/drivers/ide/pci/sgiioc4.c
index 85ffaaa39b1b..c74fef6bbc91 100644
--- a/drivers/ide/pci/sgiioc4.c
+++ b/drivers/ide/pci/sgiioc4.c
@@ -29,6 +29,7 @@
 #include <linux/mm.h>
 #include <linux/ioport.h>
 #include <linux/blkdev.h>
+#include <linux/scatterlist.h>
 #include <linux/ioc4.h>
 #include <asm/io.h>
 
@@ -537,7 +538,7 @@ sgiioc4_build_dma_table(ide_drive_t * drive, struct request *rq, int ddir)
 			}
 		}
 
-		sg++;
+		sg = sg_next(sg);
 		i--;
 	}
 
diff --git a/drivers/ide/ppc/pmac.c b/drivers/ide/ppc/pmac.c
index 7d8873839e21..9e86406bf44b 100644
--- a/drivers/ide/ppc/pmac.c
+++ b/drivers/ide/ppc/pmac.c
@@ -1539,7 +1539,7 @@ pmac_ide_build_dmatable(ide_drive_t *drive, struct request *rq)
 			cur_len -= tc;
 			++table;
 		}
-		sg++;
+		sg = sg_next(sg);
 		i--;
 	}
 
diff --git a/drivers/infiniband/hw/ipath/ipath_dma.c b/drivers/infiniband/hw/ipath/ipath_dma.c
index f87f003e3ef8..22709a4f8fc8 100644
--- a/drivers/infiniband/hw/ipath/ipath_dma.c
+++ b/drivers/infiniband/hw/ipath/ipath_dma.c
@@ -30,6 +30,7 @@
  * SOFTWARE.
  */
 
+#include <linux/scatterlist.h>
 #include <rdma/ib_verbs.h>
 
 #include "ipath_verbs.h"
@@ -96,17 +97,18 @@ static void ipath_dma_unmap_page(struct ib_device *dev,
 	BUG_ON(!valid_dma_direction(direction));
 }
 
-static int ipath_map_sg(struct ib_device *dev, struct scatterlist *sg, int nents,
-			enum dma_data_direction direction)
+static int ipath_map_sg(struct ib_device *dev, struct scatterlist *sgl,
+			int nents, enum dma_data_direction direction)
 {
+	struct scatterlist *sg;
 	u64 addr;
 	int i;
 	int ret = nents;
 
 	BUG_ON(!valid_dma_direction(direction));
 
-	for (i = 0; i < nents; i++) {
-		addr = (u64) page_address(sg[i].page);
+	for_each_sg(sgl, sg, nents, i) {
+		addr = (u64) page_address(sg->page);
 		/* TODO: handle highmem pages */
 		if (!addr) {
 			ret = 0;
diff --git a/drivers/infiniband/ulp/iser/iser_memory.c b/drivers/infiniband/ulp/iser/iser_memory.c
index e05690e3592f..f3529b6f0a33 100644
--- a/drivers/infiniband/ulp/iser/iser_memory.c
+++ b/drivers/infiniband/ulp/iser/iser_memory.c
@@ -124,17 +124,19 @@ static int iser_start_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask,
 
 	if (cmd_dir == ISER_DIR_OUT) {
 		/* copy the unaligned sg the buffer which is used for RDMA */
-		struct scatterlist *sg = (struct scatterlist *)data->buf;
+		struct scatterlist *sgl = (struct scatterlist *)data->buf;
+		struct scatterlist *sg;
 		int i;
 		char *p, *from;
 
-		for (p = mem, i = 0; i < data->size; i++) {
-			from = kmap_atomic(sg[i].page, KM_USER0);
+		p = mem;
+		for_each_sg(sgl, sg, data->size, i) {
+			from = kmap_atomic(sg->page, KM_USER0);
 			memcpy(p,
-			       from + sg[i].offset,
-			       sg[i].length);
+			       from + sg->offset,
+			       sg->length);
 			kunmap_atomic(from, KM_USER0);
-			p += sg[i].length;
+			p += sg->length;
 		}
 	}
 
@@ -176,7 +178,7 @@ void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask,
 
 	if (cmd_dir == ISER_DIR_IN) {
 		char *mem;
-		struct scatterlist *sg;
+		struct scatterlist *sgl, *sg;
 		unsigned char *p, *to;
 		unsigned int sg_size;
 		int i;
@@ -184,16 +186,17 @@ void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask,
 		/* copy back read RDMA to unaligned sg */
 		mem	= mem_copy->copy_buf;
 
-		sg	= (struct scatterlist *)iser_ctask->data[ISER_DIR_IN].buf;
+		sgl	= (struct scatterlist *)iser_ctask->data[ISER_DIR_IN].buf;
 		sg_size = iser_ctask->data[ISER_DIR_IN].size;
 
-		for (p = mem, i = 0; i < sg_size; i++){
-			to = kmap_atomic(sg[i].page, KM_SOFTIRQ0);
-			memcpy(to + sg[i].offset,
+		p = mem;
+		for_each_sg(sgl, sg, sg_size, i) {
+			to = kmap_atomic(sg->page, KM_SOFTIRQ0);
+			memcpy(to + sg->offset,
 			       p,
-			       sg[i].length);
+			       sg->length);
 			kunmap_atomic(to, KM_SOFTIRQ0);
-			p += sg[i].length;
+			p += sg->length;
 		}
 	}
 
@@ -224,7 +227,8 @@ static int iser_sg_to_page_vec(struct iser_data_buf *data,
 			       struct iser_page_vec *page_vec,
 			       struct ib_device *ibdev)
 {
-	struct scatterlist *sg = (struct scatterlist *)data->buf;
+	struct scatterlist *sgl = (struct scatterlist *)data->buf;
+	struct scatterlist *sg;
 	u64 first_addr, last_addr, page;
 	int end_aligned;
 	unsigned int cur_page = 0;
@@ -232,24 +236,25 @@ static int iser_sg_to_page_vec(struct iser_data_buf *data,
 	int i;
 
 	/* compute the offset of first element */
-	page_vec->offset = (u64) sg[0].offset & ~MASK_4K;
+	page_vec->offset = (u64) sgl[0].offset & ~MASK_4K;
 
-	for (i = 0; i < data->dma_nents; i++) {
-		unsigned int dma_len = ib_sg_dma_len(ibdev, &sg[i]);
+	for_each_sg(sgl, sg, data->dma_nents, i) {
+		unsigned int dma_len = ib_sg_dma_len(ibdev, sg);
 
 		total_sz += dma_len;
 
-		first_addr = ib_sg_dma_address(ibdev, &sg[i]);
+		first_addr = ib_sg_dma_address(ibdev, sg);
 		last_addr  = first_addr + dma_len;
 
 		end_aligned   = !(last_addr  & ~MASK_4K);
 
 		/* continue to collect page fragments till aligned or SG ends */
 		while (!end_aligned && (i + 1 < data->dma_nents)) {
+			sg = sg_next(sg);
 			i++;
-			dma_len = ib_sg_dma_len(ibdev, &sg[i]);
+			dma_len = ib_sg_dma_len(ibdev, sg);
 			total_sz += dma_len;
-			last_addr = ib_sg_dma_address(ibdev, &sg[i]) + dma_len;
+			last_addr = ib_sg_dma_address(ibdev, sg) + dma_len;
 			end_aligned = !(last_addr  & ~MASK_4K);
 		}
 
@@ -284,25 +289,26 @@ static int iser_sg_to_page_vec(struct iser_data_buf *data,
 static unsigned int iser_data_buf_aligned_len(struct iser_data_buf *data,
 					      struct ib_device *ibdev)
 {
-	struct scatterlist *sg;
+	struct scatterlist *sgl, *sg;
 	u64 end_addr, next_addr;
 	int i, cnt;
 	unsigned int ret_len = 0;
 
-	sg = (struct scatterlist *)data->buf;
+	sgl = (struct scatterlist *)data->buf;
 
-	for (cnt = 0, i = 0; i < data->dma_nents; i++, cnt++) {
+	cnt = 0;
+	for_each_sg(sgl, sg, data->dma_nents, i) {
 		/* iser_dbg("Checking sg iobuf [%d]: phys=0x%08lX "
 		   "offset: %ld sz: %ld\n", i,
-		   (unsigned long)page_to_phys(sg[i].page),
-		   (unsigned long)sg[i].offset,
-		   (unsigned long)sg[i].length); */
-		end_addr = ib_sg_dma_address(ibdev, &sg[i]) +
-			   ib_sg_dma_len(ibdev, &sg[i]);
+		   (unsigned long)page_to_phys(sg->page),
+		   (unsigned long)sg->offset,
+		   (unsigned long)sg->length); */
+		end_addr = ib_sg_dma_address(ibdev, sg) +
+			   ib_sg_dma_len(ibdev, sg);
 		/* iser_dbg("Checking sg iobuf end address "
 		       "0x%08lX\n", end_addr); */
 		if (i + 1 < data->dma_nents) {
-			next_addr = ib_sg_dma_address(ibdev, &sg[i+1]);
+			next_addr = ib_sg_dma_address(ibdev, sg_next(sg));
 			/* are i, i+1 fragments of the same page? */
 			if (end_addr == next_addr)
 				continue;
@@ -322,15 +328,16 @@ static unsigned int iser_data_buf_aligned_len(struct iser_data_buf *data,
 static void iser_data_buf_dump(struct iser_data_buf *data,
 			       struct ib_device *ibdev)
 {
-	struct scatterlist *sg = (struct scatterlist *)data->buf;
+	struct scatterlist *sgl = (struct scatterlist *)data->buf;
+	struct scatterlist *sg;
 	int i;
 
-	for (i = 0; i < data->dma_nents; i++)
+	for_each_sg(sgl, sg, data->dma_nents, i)
 		iser_err("sg[%d] dma_addr:0x%lX page:0x%p "
 			 "off:0x%x sz:0x%x dma_len:0x%x\n",
-			 i, (unsigned long)ib_sg_dma_address(ibdev, &sg[i]),
-			 sg[i].page, sg[i].offset,
-			 sg[i].length, ib_sg_dma_len(ibdev, &sg[i]));
+			 i, (unsigned long)ib_sg_dma_address(ibdev, sg),
+			 sg->page, sg->offset,
+			 sg->length, ib_sg_dma_len(ibdev, sg));
 }
 
 static void iser_dump_page_vec(struct iser_page_vec *page_vec)
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 8216a6f75be5..64fee90bb68b 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -441,33 +441,12 @@ static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
 	return clone;
 }
 
-static void crypt_free_buffer_pages(struct crypt_config *cc,
-                                    struct bio *clone, unsigned int bytes)
+static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
 {
-	unsigned int i, start, end;
+	unsigned int i;
 	struct bio_vec *bv;
 
-	/*
-	 * This is ugly, but Jens Axboe thinks that using bi_idx in the
-	 * endio function is too dangerous at the moment, so I calculate the
-	 * correct position using bi_vcnt and bi_size.
-	 * The bv_offset and bv_len fields might already be modified but we
-	 * know that we always allocated whole pages.
-	 * A fix to the bi_idx issue in the kernel is in the works, so
-	 * we will hopefully be able to revert to the cleaner solution soon.
-	 */
-	i = clone->bi_vcnt - 1;
-	bv = bio_iovec_idx(clone, i);
-	end = (i << PAGE_SHIFT) + (bv->bv_offset + bv->bv_len) - clone->bi_size;
-	start = end - bytes;
-
-	start >>= PAGE_SHIFT;
-	if (!clone->bi_size)
-		end = clone->bi_vcnt;
-	else
-		end >>= PAGE_SHIFT;
-
-	for (i = start; i < end; i++) {
+	for (i = 0; i < clone->bi_vcnt; i++) {
 		bv = bio_iovec_idx(clone, i);
 		BUG_ON(!bv->bv_page);
 		mempool_free(bv->bv_page, cc->page_pool);
@@ -519,7 +498,7 @@ static void crypt_endio(struct bio *clone, int error)
 	 * free the processed pages
 	 */
 	if (!read_io) {
-		crypt_free_buffer_pages(cc, clone, clone->bi_size);
+		crypt_free_buffer_pages(cc, clone);
 		goto out;
 	}
 
@@ -608,7 +587,7 @@ static void process_write(struct dm_crypt_io *io)
 		ctx.idx_out = 0;
 
 		if (unlikely(crypt_convert(cc, &ctx) < 0)) {
-			crypt_free_buffer_pages(cc, clone, clone->bi_size);
+			crypt_free_buffer_pages(cc, clone);
 			bio_put(clone);
 			dec_pending(io, -EIO);
 			return;
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 2bcde5798b5a..fbe477bb2c68 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -999,33 +999,6 @@ void dm_table_unplug_all(struct dm_table *t)
 	}
 }
 
-int dm_table_flush_all(struct dm_table *t)
-{
-	struct list_head *d, *devices = dm_table_get_devices(t);
-	int ret = 0;
-	unsigned i;
-
-	for (i = 0; i < t->num_targets; i++)
-		if (t->targets[i].type->flush)
-			t->targets[i].type->flush(&t->targets[i]);
-
-	for (d = devices->next; d != devices; d = d->next) {
-		struct dm_dev *dd = list_entry(d, struct dm_dev, list);
-		struct request_queue *q = bdev_get_queue(dd->bdev);
-		int err;
-
-		if (!q->issue_flush_fn)
-			err = -EOPNOTSUPP;
-		else
-			err = q->issue_flush_fn(q, dd->bdev->bd_disk, NULL);
-
-		if (!ret)
-			ret = err;
-	}
-
-	return ret;
-}
-
 struct mapped_device *dm_table_get_md(struct dm_table *t)
 {
 	dm_get(t->md);
@@ -1043,4 +1016,3 @@ EXPORT_SYMBOL(dm_table_get_md);
 EXPORT_SYMBOL(dm_table_put);
 EXPORT_SYMBOL(dm_table_get);
 EXPORT_SYMBOL(dm_table_unplug_all);
-EXPORT_SYMBOL(dm_table_flush_all);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 167765c47747..d837d37f6209 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -840,21 +840,6 @@ static int dm_request(struct request_queue *q, struct bio *bio)
 	return 0;
 }
 
-static int dm_flush_all(struct request_queue *q, struct gendisk *disk,
-			sector_t *error_sector)
-{
-	struct mapped_device *md = q->queuedata;
-	struct dm_table *map = dm_get_table(md);
-	int ret = -ENXIO;
-
-	if (map) {
-		ret = dm_table_flush_all(map);
-		dm_table_put(map);
-	}
-
-	return ret;
-}
-
 static void dm_unplug_all(struct request_queue *q)
 {
 	struct mapped_device *md = q->queuedata;
@@ -1003,7 +988,6 @@ static struct mapped_device *alloc_dev(int minor)
 	blk_queue_make_request(md->queue, dm_request);
 	blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
 	md->queue->unplug_fn = dm_unplug_all;
-	md->queue->issue_flush_fn = dm_flush_all;
 
 	md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
 	if (!md->io_pool)
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 462ee652a890..4b3faa45277e 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -111,7 +111,6 @@ void dm_table_postsuspend_targets(struct dm_table *t);
 int dm_table_resume_targets(struct dm_table *t);
 int dm_table_any_congested(struct dm_table *t, int bdi_bits);
 void dm_table_unplug_all(struct dm_table *t);
-int dm_table_flush_all(struct dm_table *t);
 
 /*-----------------------------------------------------------------
  * A registry of target types.
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 550148770bb2..56a11f6c127b 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -92,25 +92,6 @@ static void linear_unplug(struct request_queue *q)
 	}
 }
 
-static int linear_issue_flush(struct request_queue *q, struct gendisk *disk,
-			      sector_t *error_sector)
-{
-	mddev_t *mddev = q->queuedata;
-	linear_conf_t *conf = mddev_to_conf(mddev);
-	int i, ret = 0;
-
-	for (i=0; i < mddev->raid_disks && ret == 0; i++) {
-		struct block_device *bdev = conf->disks[i].rdev->bdev;
-		struct request_queue *r_queue = bdev_get_queue(bdev);
-
-		if (!r_queue->issue_flush_fn)
-			ret = -EOPNOTSUPP;
-		else
-			ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector);
-	}
-	return ret;
-}
-
 static int linear_congested(void *data, int bits)
 {
 	mddev_t *mddev = data;
@@ -279,7 +260,6 @@ static int linear_run (mddev_t *mddev)
 
 	blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
 	mddev->queue->unplug_fn = linear_unplug;
-	mddev->queue->issue_flush_fn = linear_issue_flush;
 	mddev->queue->backing_dev_info.congested_fn = linear_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
 	return 0;
diff --git a/drivers/md/md.c b/drivers/md/md.c
index acf1b81b47cb..0dc563d76b39 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3463,7 +3463,6 @@ static int do_md_stop(mddev_t * mddev, int mode)
 			mddev->pers->stop(mddev);
 			mddev->queue->merge_bvec_fn = NULL;
 			mddev->queue->unplug_fn = NULL;
-			mddev->queue->issue_flush_fn = NULL;
 			mddev->queue->backing_dev_info.congested_fn = NULL;
 			if (mddev->pers->sync_request)
 				sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index f2a63f394ad9..b35731cceac6 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -194,35 +194,6 @@ static void multipath_status (struct seq_file *seq, mddev_t *mddev)
 	seq_printf (seq, "]");
 }
 
-static int multipath_issue_flush(struct request_queue *q, struct gendisk *disk,
-				 sector_t *error_sector)
-{
-	mddev_t *mddev = q->queuedata;
-	multipath_conf_t *conf = mddev_to_conf(mddev);
-	int i, ret = 0;
-
-	rcu_read_lock();
-	for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-		mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev);
-		if (rdev && !test_bit(Faulty, &rdev->flags)) {
-			struct block_device *bdev = rdev->bdev;
-			struct request_queue *r_queue = bdev_get_queue(bdev);
-
-			if (!r_queue->issue_flush_fn)
-				ret = -EOPNOTSUPP;
-			else {
-				atomic_inc(&rdev->nr_pending);
-				rcu_read_unlock();
-				ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
-							      error_sector);
-				rdev_dec_pending(rdev, mddev);
-				rcu_read_lock();
-			}
-		}
-	}
-	rcu_read_unlock();
-	return ret;
-}
 static int multipath_congested(void *data, int bits)
 {
 	mddev_t *mddev = data;
@@ -527,7 +498,6 @@ static int multipath_run (mddev_t *mddev)
 	mddev->array_size = mddev->size;
 
 	mddev->queue->unplug_fn = multipath_unplug;
-	mddev->queue->issue_flush_fn = multipath_issue_flush;
 	mddev->queue->backing_dev_info.congested_fn = multipath_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
 
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index ef0da2d84959..e79e1a538d44 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -40,26 +40,6 @@ static void raid0_unplug(struct request_queue *q)
 	}
 }
 
-static int raid0_issue_flush(struct request_queue *q, struct gendisk *disk,
-			     sector_t *error_sector)
-{
-	mddev_t *mddev = q->queuedata;
-	raid0_conf_t *conf = mddev_to_conf(mddev);
-	mdk_rdev_t **devlist = conf->strip_zone[0].dev;
-	int i, ret = 0;
-
-	for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-		struct block_device *bdev = devlist[i]->bdev;
-		struct request_queue *r_queue = bdev_get_queue(bdev);
-
-		if (!r_queue->issue_flush_fn)
-			ret = -EOPNOTSUPP;
-		else
-			ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector);
-	}
-	return ret;
-}
-
 static int raid0_congested(void *data, int bits)
 {
 	mddev_t *mddev = data;
@@ -250,7 +230,6 @@ static int create_strip_zones (mddev_t *mddev)
 
 	mddev->queue->unplug_fn = raid0_unplug;
 
-	mddev->queue->issue_flush_fn = raid0_issue_flush;
 	mddev->queue->backing_dev_info.congested_fn = raid0_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
 
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 6d03bea6fa58..0bcefad82413 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -567,36 +567,6 @@ static void raid1_unplug(struct request_queue *q)
 	md_wakeup_thread(mddev->thread);
 }
 
-static int raid1_issue_flush(struct request_queue *q, struct gendisk *disk,
-			     sector_t *error_sector)
-{
-	mddev_t *mddev = q->queuedata;
-	conf_t *conf = mddev_to_conf(mddev);
-	int i, ret = 0;
-
-	rcu_read_lock();
-	for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
-		if (rdev && !test_bit(Faulty, &rdev->flags)) {
-			struct block_device *bdev = rdev->bdev;
-			struct request_queue *r_queue = bdev_get_queue(bdev);
-
-			if (!r_queue->issue_flush_fn)
-				ret = -EOPNOTSUPP;
-			else {
-				atomic_inc(&rdev->nr_pending);
-				rcu_read_unlock();
-				ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
-							      error_sector);
-				rdev_dec_pending(rdev, mddev);
-				rcu_read_lock();
-			}
-		}
-	}
-	rcu_read_unlock();
-	return ret;
-}
-
 static int raid1_congested(void *data, int bits)
 {
 	mddev_t *mddev = data;
@@ -1997,7 +1967,6 @@ static int run(mddev_t *mddev)
 	mddev->array_size = mddev->size;
 
 	mddev->queue->unplug_fn = raid1_unplug;
-	mddev->queue->issue_flush_fn = raid1_issue_flush;
 	mddev->queue->backing_dev_info.congested_fn = raid1_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
 
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 25a96c42bdb0..fc6607acb6e4 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -611,36 +611,6 @@ static void raid10_unplug(struct request_queue *q)
 	md_wakeup_thread(mddev->thread);
 }
 
-static int raid10_issue_flush(struct request_queue *q, struct gendisk *disk,
-			     sector_t *error_sector)
-{
-	mddev_t *mddev = q->queuedata;
-	conf_t *conf = mddev_to_conf(mddev);
-	int i, ret = 0;
-
-	rcu_read_lock();
-	for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
-		if (rdev && !test_bit(Faulty, &rdev->flags)) {
-			struct block_device *bdev = rdev->bdev;
-			struct request_queue *r_queue = bdev_get_queue(bdev);
-
-			if (!r_queue->issue_flush_fn)
-				ret = -EOPNOTSUPP;
-			else {
-				atomic_inc(&rdev->nr_pending);
-				rcu_read_unlock();
-				ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
-							      error_sector);
-				rdev_dec_pending(rdev, mddev);
-				rcu_read_lock();
-			}
-		}
-	}
-	rcu_read_unlock();
-	return ret;
-}
-
 static int raid10_congested(void *data, int bits)
 {
 	mddev_t *mddev = data;
@@ -2118,7 +2088,6 @@ static int run(mddev_t *mddev)
 	mddev->resync_max_sectors = size << conf->chunk_shift;
 
 	mddev->queue->unplug_fn = raid10_unplug;
-	mddev->queue->issue_flush_fn = raid10_issue_flush;
 	mddev->queue->backing_dev_info.congested_fn = raid10_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
 
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index caaca9e178bc..8ee181a01f52 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3204,36 +3204,6 @@ static void raid5_unplug_device(struct request_queue *q)
 	unplug_slaves(mddev);
 }
 
-static int raid5_issue_flush(struct request_queue *q, struct gendisk *disk,
-			     sector_t *error_sector)
-{
-	mddev_t *mddev = q->queuedata;
-	raid5_conf_t *conf = mddev_to_conf(mddev);
-	int i, ret = 0;
-
-	rcu_read_lock();
-	for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-		mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
-		if (rdev && !test_bit(Faulty, &rdev->flags)) {
-			struct block_device *bdev = rdev->bdev;
-			struct request_queue *r_queue = bdev_get_queue(bdev);
-
-			if (!r_queue->issue_flush_fn)
-				ret = -EOPNOTSUPP;
-			else {
-				atomic_inc(&rdev->nr_pending);
-				rcu_read_unlock();
-				ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
-							      error_sector);
-				rdev_dec_pending(rdev, mddev);
-				rcu_read_lock();
-			}
-		}
-	}
-	rcu_read_unlock();
-	return ret;
-}
-
 static int raid5_congested(void *data, int bits)
 {
 	mddev_t *mddev = data;
@@ -4263,7 +4233,6 @@ static int run(mddev_t *mddev)
 		       mdname(mddev));
 
 	mddev->queue->unplug_fn = raid5_unplug_device;
-	mddev->queue->issue_flush_fn = raid5_issue_flush;
 	mddev->queue->backing_dev_info.congested_data = mddev;
 	mddev->queue->backing_dev_info.congested_fn = raid5_congested;
 
diff --git a/drivers/message/fusion/mptscsih.c b/drivers/message/fusion/mptscsih.c
index 822a3aa4fae5..626bb3c9af2b 100644
--- a/drivers/message/fusion/mptscsih.c
+++ b/drivers/message/fusion/mptscsih.c
@@ -293,7 +293,7 @@ nextSGEset:
 	for (ii=0; ii < (numSgeThisFrame-1); ii++) {
 		thisxfer = sg_dma_len(sg);
 		if (thisxfer == 0) {
-			sg ++; /* Get next SG element from the OS */
+			sg = sg_next(sg); /* Get next SG element from the OS */
 			sg_done++;
 			continue;
 		}
@@ -301,7 +301,7 @@ nextSGEset:
 		v2 = sg_dma_address(sg);
 		mptscsih_add_sge(psge, sgflags | thisxfer, v2);
 
-		sg++;		/* Get next SG element from the OS */
+		sg = sg_next(sg);	/* Get next SG element from the OS */
 		psge += (sizeof(u32) + sizeof(dma_addr_t));
 		sgeOffset += (sizeof(u32) + sizeof(dma_addr_t));
 		sg_done++;
@@ -322,7 +322,7 @@ nextSGEset:
 		v2 = sg_dma_address(sg);
 		mptscsih_add_sge(psge, sgflags | thisxfer, v2);
 		/*
-		sg++;
+		sg = sg_next(sg);
 		psge += (sizeof(u32) + sizeof(dma_addr_t));
 		*/
 		sgeOffset += (sizeof(u32) + sizeof(dma_addr_t));
diff --git a/drivers/message/i2o/i2o_block.c b/drivers/message/i2o/i2o_block.c
index 50b2c7334410..d602ba6d5417 100644
--- a/drivers/message/i2o/i2o_block.c
+++ b/drivers/message/i2o/i2o_block.c
@@ -149,29 +149,6 @@ static int i2o_block_device_flush(struct i2o_device *dev)
 };
 
 /**
- *	i2o_block_issue_flush - device-flush interface for block-layer
- *	@queue: the request queue of the device which should be flushed
- *	@disk: gendisk
- *	@error_sector: error offset
- *
- *	Helper function to provide flush functionality to block-layer.
- *
- *	Returns 0 on success or negative error code on failure.
- */
-
-static int i2o_block_issue_flush(struct request_queue * queue, struct gendisk *disk,
-				 sector_t * error_sector)
-{
-	struct i2o_block_device *i2o_blk_dev = queue->queuedata;
-	int rc = -ENODEV;
-
-	if (likely(i2o_blk_dev))
-		rc = i2o_block_device_flush(i2o_blk_dev->i2o_dev);
-
-	return rc;
-}
-
-/**
  *	i2o_block_device_mount - Mount (load) the media of device dev
  *	@dev: I2O device which should receive the mount request
  *	@media_id: Media Identifier
@@ -1009,7 +986,6 @@ static struct i2o_block_device *i2o_block_device_alloc(void)
 	}
 
 	blk_queue_prep_rq(queue, i2o_block_prep_req_fn);
-	blk_queue_issue_flush_fn(queue, i2o_block_issue_flush);
 
 	gd->major = I2O_MAJOR;
 	gd->queue = queue;
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index b0abc7d92805..a5d0354bbbda 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -153,14 +153,14 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock
 			blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
 			blk_queue_max_segment_size(mq->queue, bouncesz);
 
-			mq->sg = kmalloc(sizeof(struct scatterlist),
+			mq->sg = kzalloc(sizeof(struct scatterlist),
 				GFP_KERNEL);
 			if (!mq->sg) {
 				ret = -ENOMEM;
 				goto cleanup_queue;
 			}
 
-			mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
+			mq->bounce_sg = kzalloc(sizeof(struct scatterlist) *
 				bouncesz / 512, GFP_KERNEL);
 			if (!mq->bounce_sg) {
 				ret = -ENOMEM;
@@ -177,7 +177,7 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock
 		blk_queue_max_hw_segments(mq->queue, host->max_hw_segs);
 		blk_queue_max_segment_size(mq->queue, host->max_seg_size);
 
-		mq->sg = kmalloc(sizeof(struct scatterlist) *
+		mq->sg = kzalloc(sizeof(struct scatterlist) *
 			host->max_phys_segs, GFP_KERNEL);
 		if (!mq->sg) {
 			ret = -ENOMEM;
diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index 16e5563e0c65..57cac7008e0b 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -34,6 +34,7 @@
 #include <linux/slab.h>
 #include <linux/mempool.h>
 #include <linux/syscalls.h>
+#include <linux/scatterlist.h>
 #include <linux/ioctl.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_tcq.h>
diff --git a/drivers/s390/scsi/zfcp_qdio.c b/drivers/s390/scsi/zfcp_qdio.c
index 3f105fdcf239..51d92b196ee7 100644
--- a/drivers/s390/scsi/zfcp_qdio.c
+++ b/drivers/s390/scsi/zfcp_qdio.c
@@ -590,7 +590,7 @@ zfcp_qdio_sbals_from_segment(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
  */
 int
 zfcp_qdio_sbals_from_sg(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
-                        struct scatterlist *sg,	int sg_count, int max_sbals)
+                        struct scatterlist *sgl, int sg_count, int max_sbals)
 {
 	int sg_index;
 	struct scatterlist *sg_segment;
@@ -606,9 +606,7 @@ zfcp_qdio_sbals_from_sg(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
 	sbale->flags |= sbtype;
 
 	/* process all segements of scatter-gather list */
-	for (sg_index = 0, sg_segment = sg, bytes = 0;
-	     sg_index < sg_count;
-	     sg_index++, sg_segment++) {
+	for_each_sg(sgl, sg_segment, sg_count, sg_index) {
 		retval = zfcp_qdio_sbals_from_segment(
 				fsf_req,
 				sbtype,
diff --git a/drivers/scsi/3w-9xxx.c b/drivers/scsi/3w-9xxx.c
index efd9d8d3a890..fb14014ee16e 100644
--- a/drivers/scsi/3w-9xxx.c
+++ b/drivers/scsi/3w-9xxx.c
@@ -1990,6 +1990,7 @@ static struct scsi_host_template driver_template = {
 	.max_sectors		= TW_MAX_SECTORS,
 	.cmd_per_lun		= TW_MAX_CMDS_PER_LUN,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 	.shost_attrs		= twa_host_attrs,
 	.emulated		= 1
 };
diff --git a/drivers/scsi/3w-xxxx.c b/drivers/scsi/3w-xxxx.c
index c7995fc216e8..a64153b96034 100644
--- a/drivers/scsi/3w-xxxx.c
+++ b/drivers/scsi/3w-xxxx.c
@@ -2261,6 +2261,7 @@ static struct scsi_host_template driver_template = {
 	.max_sectors		= TW_MAX_SECTORS,
 	.cmd_per_lun		= TW_MAX_CMDS_PER_LUN,	
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 	.shost_attrs		= tw_host_attrs,
 	.emulated		= 1
 };
diff --git a/drivers/scsi/BusLogic.c b/drivers/scsi/BusLogic.c
index 9b206176f717..49e1ffa4b2ff 100644
--- a/drivers/scsi/BusLogic.c
+++ b/drivers/scsi/BusLogic.c
@@ -3575,6 +3575,7 @@ static struct scsi_host_template Bus_Logic_template = {
 	.unchecked_isa_dma = 1,
 	.max_sectors = 128,
 	.use_clustering = ENABLE_CLUSTERING,
+	.use_sg_chaining = ENABLE_SG_CHAINING,
 };
 
 /*
diff --git a/drivers/scsi/NCR53c406a.c b/drivers/scsi/NCR53c406a.c
index eda8c48f6be7..3168a1794849 100644
--- a/drivers/scsi/NCR53c406a.c
+++ b/drivers/scsi/NCR53c406a.c
@@ -1066,7 +1066,8 @@ static struct scsi_host_template driver_template =
      .sg_tablesize      	= 32			/*SG_ALL*/ /*SG_NONE*/, 
      .cmd_per_lun       	= 1			/* commands per lun */, 
      .unchecked_isa_dma 	= 1			/* unchecked_isa_dma */,
-     .use_clustering    	= ENABLE_CLUSTERING                               
+     .use_clustering    	= ENABLE_CLUSTERING,
+     .use_sg_chaining           = ENABLE_SG_CHAINING,
 };
 
 #include "scsi_module.c"
diff --git a/drivers/scsi/a100u2w.c b/drivers/scsi/a100u2w.c
index f608d4a1d6da..d3a6d15fb77a 100644
--- a/drivers/scsi/a100u2w.c
+++ b/drivers/scsi/a100u2w.c
@@ -1071,6 +1071,7 @@ static struct scsi_host_template inia100_template = {
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun 		= 1,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 };
 
 static int __devinit inia100_probe_one(struct pci_dev *pdev,
diff --git a/drivers/scsi/aacraid/linit.c b/drivers/scsi/aacraid/linit.c
index a7f42a17b5c7..038980be763d 100644
--- a/drivers/scsi/aacraid/linit.c
+++ b/drivers/scsi/aacraid/linit.c
@@ -944,6 +944,7 @@ static struct scsi_host_template aac_driver_template = {
 	.cmd_per_lun    		= AAC_NUM_IO_FIB, 
 #endif	
 	.use_clustering			= ENABLE_CLUSTERING,
+	.use_sg_chaining		= ENABLE_SG_CHAINING,
 	.emulated                       = 1,
 };
 
diff --git a/drivers/scsi/aha1542.c b/drivers/scsi/aha1542.c
index cbbfbc9f3e0f..961a1882cb7e 100644
--- a/drivers/scsi/aha1542.c
+++ b/drivers/scsi/aha1542.c
@@ -61,15 +61,15 @@ static void BAD_DMA(void *address, unsigned int length)
 }
 
 static void BAD_SG_DMA(Scsi_Cmnd * SCpnt,
-		       struct scatterlist *sgpnt,
+		       struct scatterlist *sgp,
 		       int nseg,
 		       int badseg)
 {
 	printk(KERN_CRIT "sgpnt[%d:%d] page %p/0x%llx length %u\n",
 	       badseg, nseg,
-	       page_address(sgpnt[badseg].page) + sgpnt[badseg].offset,
-	       (unsigned long long)SCSI_SG_PA(&sgpnt[badseg]),
-	       sgpnt[badseg].length);
+	       page_address(sgp->page) + sgp->offset,
+	       (unsigned long long)SCSI_SG_PA(sgp),
+	       sgp->length);
 
 	/*
 	 * Not safe to continue.
@@ -691,7 +691,7 @@ static int aha1542_queuecommand(Scsi_Cmnd * SCpnt, void (*done) (Scsi_Cmnd *))
 	memcpy(ccb[mbo].cdb, cmd, ccb[mbo].cdblen);
 
 	if (SCpnt->use_sg) {
-		struct scatterlist *sgpnt;
+		struct scatterlist *sg;
 		struct chain *cptr;
 #ifdef DEBUG
 		unsigned char *ptr;
@@ -699,23 +699,21 @@ static int aha1542_queuecommand(Scsi_Cmnd * SCpnt, void (*done) (Scsi_Cmnd *))
 		int i;
 		ccb[mbo].op = 2;	/* SCSI Initiator Command  w/scatter-gather */
 		SCpnt->host_scribble = kmalloc(512, GFP_KERNEL | GFP_DMA);
-		sgpnt = (struct scatterlist *) SCpnt->request_buffer;
 		cptr = (struct chain *) SCpnt->host_scribble;
 		if (cptr == NULL) {
 			/* free the claimed mailbox slot */
 			HOSTDATA(SCpnt->device->host)->SCint[mbo] = NULL;
 			return SCSI_MLQUEUE_HOST_BUSY;
 		}
-		for (i = 0; i < SCpnt->use_sg; i++) {
-			if (sgpnt[i].length == 0 || SCpnt->use_sg > 16 ||
-			    (((int) sgpnt[i].offset) & 1) || (sgpnt[i].length & 1)) {
+		scsi_for_each_sg(SCpnt, sg, SCpnt->use_sg, i) {
+			if (sg->length == 0 || SCpnt->use_sg > 16 ||
+			    (((int) sg->offset) & 1) || (sg->length & 1)) {
 				unsigned char *ptr;
 				printk(KERN_CRIT "Bad segment list supplied to aha1542.c (%d, %d)\n", SCpnt->use_sg, i);
-				for (i = 0; i < SCpnt->use_sg; i++) {
+				scsi_for_each_sg(SCpnt, sg, SCpnt->use_sg, i) {
 					printk(KERN_CRIT "%d: %p %d\n", i,
-					       (page_address(sgpnt[i].page) +
-						sgpnt[i].offset),
-					       sgpnt[i].length);
+					       (page_address(sg->page) +
+						sg->offset), sg->length);
 				};
 				printk(KERN_CRIT "cptr %x: ", (unsigned int) cptr);
 				ptr = (unsigned char *) &cptr[i];
@@ -723,10 +721,10 @@ static int aha1542_queuecommand(Scsi_Cmnd * SCpnt, void (*done) (Scsi_Cmnd *))
 					printk("%02x ", ptr[i]);
 				panic("Foooooooood fight!");
 			};
-			any2scsi(cptr[i].dataptr, SCSI_SG_PA(&sgpnt[i]));
-			if (SCSI_SG_PA(&sgpnt[i]) + sgpnt[i].length - 1 > ISA_DMA_THRESHOLD)
-				BAD_SG_DMA(SCpnt, sgpnt, SCpnt->use_sg, i);
-			any2scsi(cptr[i].datalen, sgpnt[i].length);
+			any2scsi(cptr[i].dataptr, SCSI_SG_PA(sg));
+			if (SCSI_SG_PA(sg) + sg->length - 1 > ISA_DMA_THRESHOLD)
+				BAD_SG_DMA(SCpnt, sg, SCpnt->use_sg, i);
+			any2scsi(cptr[i].datalen, sg->length);
 		};
 		any2scsi(ccb[mbo].datalen, SCpnt->use_sg * sizeof(struct chain));
 		any2scsi(ccb[mbo].dataptr, SCSI_BUF_PA(cptr));
diff --git a/drivers/scsi/aha1740.c b/drivers/scsi/aha1740.c
index e4a4f3a965d9..f6722fd46008 100644
--- a/drivers/scsi/aha1740.c
+++ b/drivers/scsi/aha1740.c
@@ -563,6 +563,7 @@ static struct scsi_host_template aha1740_template = {
 	.sg_tablesize     = AHA1740_SCATTER,
 	.cmd_per_lun      = AHA1740_CMDLUN,
 	.use_clustering   = ENABLE_CLUSTERING,
+	.use_sg_chaining  = ENABLE_SG_CHAINING,
 	.eh_abort_handler = aha1740_eh_abort_handler,
 };
 
diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c b/drivers/scsi/aic7xxx/aic79xx_osm.c
index a055a96e3ad3..42c0f14a262c 100644
--- a/drivers/scsi/aic7xxx/aic79xx_osm.c
+++ b/drivers/scsi/aic7xxx/aic79xx_osm.c
@@ -766,6 +766,7 @@ struct scsi_host_template aic79xx_driver_template = {
 	.max_sectors		= 8192,
 	.cmd_per_lun		= 2,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 	.slave_alloc		= ahd_linux_slave_alloc,
 	.slave_configure	= ahd_linux_slave_configure,
 	.target_alloc		= ahd_linux_target_alloc,
diff --git a/drivers/scsi/aic7xxx/aic7xxx_osm.c b/drivers/scsi/aic7xxx/aic7xxx_osm.c
index 2e9c38f2e8a6..7770befbf50c 100644
--- a/drivers/scsi/aic7xxx/aic7xxx_osm.c
+++ b/drivers/scsi/aic7xxx/aic7xxx_osm.c
@@ -747,6 +747,7 @@ struct scsi_host_template aic7xxx_driver_template = {
 	.max_sectors		= 8192,
 	.cmd_per_lun		= 2,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 	.slave_alloc		= ahc_linux_slave_alloc,
 	.slave_configure	= ahc_linux_slave_configure,
 	.target_alloc		= ahc_linux_target_alloc,
diff --git a/drivers/scsi/aic7xxx_old.c b/drivers/scsi/aic7xxx_old.c
index 1a71b0236c97..4025608d6964 100644
--- a/drivers/scsi/aic7xxx_old.c
+++ b/drivers/scsi/aic7xxx_old.c
@@ -11142,6 +11142,7 @@ static struct scsi_host_template driver_template = {
 	.max_sectors		= 2048,
 	.cmd_per_lun		= 3,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 };
 
 #include "scsi_module.c"
diff --git a/drivers/scsi/aic94xx/aic94xx_task.c b/drivers/scsi/aic94xx/aic94xx_task.c
index f2b23e01401a..ee0a98bffcd4 100644
--- a/drivers/scsi/aic94xx/aic94xx_task.c
+++ b/drivers/scsi/aic94xx/aic94xx_task.c
@@ -94,7 +94,7 @@ static inline int asd_map_scatterlist(struct sas_task *task,
 			res = -ENOMEM;
 			goto err_unmap;
 		}
-		for (sc = task->scatter, i = 0; i < num_sg; i++, sc++) {
+		for_each_sg(task->scatter, sc, num_sg, i) {
 			struct sg_el *sg =
 				&((struct sg_el *)ascb->sg_arr->vaddr)[i];
 			sg->bus_addr = cpu_to_le64((u64)sg_dma_address(sc));
@@ -103,7 +103,7 @@ static inline int asd_map_scatterlist(struct sas_task *task,
 				sg->flags |= ASD_SG_EL_LIST_EOL;
 		}
 
-		for (sc = task->scatter, i = 0; i < 2; i++, sc++) {
+		for_each_sg(task->scatter, sc, 2, i) {
 			sg_arr[i].bus_addr =
 				cpu_to_le64((u64)sg_dma_address(sc));
 			sg_arr[i].size = cpu_to_le32((u32)sg_dma_len(sc));
@@ -115,7 +115,7 @@ static inline int asd_map_scatterlist(struct sas_task *task,
 		sg_arr[2].bus_addr=cpu_to_le64((u64)ascb->sg_arr->dma_handle);
 	} else {
 		int i;
-		for (sc = task->scatter, i = 0; i < num_sg; i++, sc++) {
+		for_each_sg(task->scatter, sc, num_sg, i) {
 			sg_arr[i].bus_addr =
 				cpu_to_le64((u64)sg_dma_address(sc));
 			sg_arr[i].size = cpu_to_le32((u32)sg_dma_len(sc));
diff --git a/drivers/scsi/arcmsr/arcmsr_hba.c b/drivers/scsi/arcmsr/arcmsr_hba.c
index cfcf40159eab..f81777586b8f 100644
--- a/drivers/scsi/arcmsr/arcmsr_hba.c
+++ b/drivers/scsi/arcmsr/arcmsr_hba.c
@@ -122,6 +122,7 @@ static struct scsi_host_template arcmsr_scsi_host_template = {
 	.max_sectors    	= ARCMSR_MAX_XFER_SECTORS,
 	.cmd_per_lun		= ARCMSR_MAX_CMD_PERLUN,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 	.shost_attrs		= arcmsr_host_attrs,
 };
 #ifdef CONFIG_SCSI_ARCMSR_AER
diff --git a/drivers/scsi/dc395x.c b/drivers/scsi/dc395x.c
index 1591824cf4b3..fd42d4789202 100644
--- a/drivers/scsi/dc395x.c
+++ b/drivers/scsi/dc395x.c
@@ -4765,6 +4765,7 @@ static struct scsi_host_template dc395x_driver_template = {
 	.eh_bus_reset_handler   = dc395x_eh_bus_reset,
 	.unchecked_isa_dma      = 0,
 	.use_clustering         = DISABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 };
 
 
diff --git a/drivers/scsi/dpt_i2o.c b/drivers/scsi/dpt_i2o.c
index bea9d659af15..8258506ba7d7 100644
--- a/drivers/scsi/dpt_i2o.c
+++ b/drivers/scsi/dpt_i2o.c
@@ -3295,6 +3295,7 @@ static struct scsi_host_template adpt_template = {
 	.this_id		= 7,
 	.cmd_per_lun		= 1,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 };
 
 static s32 adpt_scsi_register(adpt_hba* pHba)
diff --git a/drivers/scsi/eata.c b/drivers/scsi/eata.c
index ec2233114bc9..7ead5210de96 100644
--- a/drivers/scsi/eata.c
+++ b/drivers/scsi/eata.c
@@ -523,7 +523,8 @@ static struct scsi_host_template driver_template = {
 	.slave_configure = eata2x_slave_configure,
 	.this_id = 7,
 	.unchecked_isa_dma = 1,
-	.use_clustering = ENABLE_CLUSTERING
+	.use_clustering = ENABLE_CLUSTERING,
+	.use_sg_chaining = ENABLE_SG_CHAINING,
 };
 
 #if !defined(__BIG_ENDIAN_BITFIELD) && !defined(__LITTLE_ENDIAN_BITFIELD)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index adc9559cb6f4..112ab6abe62b 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -343,6 +343,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 	shost->use_clustering = sht->use_clustering;
 	shost->ordered_tag = sht->ordered_tag;
 	shost->active_mode = sht->supported_mode;
+	shost->use_sg_chaining = sht->use_sg_chaining;
 
 	if (sht->max_host_blocked)
 		shost->max_host_blocked = sht->max_host_blocked;
diff --git a/drivers/scsi/hptiop.c b/drivers/scsi/hptiop.c
index 8b384fa7f048..8515054cdf70 100644
--- a/drivers/scsi/hptiop.c
+++ b/drivers/scsi/hptiop.c
@@ -655,6 +655,7 @@ static struct scsi_host_template driver_template = {
 	.unchecked_isa_dma          = 0,
 	.emulated                   = 0,
 	.use_clustering             = ENABLE_CLUSTERING,
+	.use_sg_chaining            = ENABLE_SG_CHAINING,
 	.proc_name                  = driver_name,
 	.shost_attrs                = hptiop_attrs,
 	.this_id                    = -1,
diff --git a/drivers/scsi/ibmmca.c b/drivers/scsi/ibmmca.c
index 1a924e9b0271..714e6273a70d 100644
--- a/drivers/scsi/ibmmca.c
+++ b/drivers/scsi/ibmmca.c
@@ -1501,6 +1501,7 @@ static struct scsi_host_template ibmmca_driver_template = {
           .sg_tablesize   = 16,
           .cmd_per_lun    = 1,
           .use_clustering = ENABLE_CLUSTERING,
+          .use_sg_chaining = ENABLE_SG_CHAINING,
 };
 
 static int ibmmca_probe(struct device *dev)
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index cda0cc3d182f..22d91ee173c5 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -1548,6 +1548,7 @@ static struct scsi_host_template driver_template = {
 	.this_id = -1,
 	.sg_tablesize = SG_ALL,
 	.use_clustering = ENABLE_CLUSTERING,
+	.use_sg_chaining = ENABLE_SG_CHAINING,
 	.shost_attrs = ibmvscsi_attrs,
 };
 
diff --git a/drivers/scsi/ide-scsi.c b/drivers/scsi/ide-scsi.c
index d81bb076a15a..d297f64cd432 100644
--- a/drivers/scsi/ide-scsi.c
+++ b/drivers/scsi/ide-scsi.c
@@ -70,6 +70,7 @@ typedef struct idescsi_pc_s {
 	u8 *buffer;				/* Data buffer */
 	u8 *current_position;			/* Pointer into the above buffer */
 	struct scatterlist *sg;			/* Scatter gather table */
+	struct scatterlist *last_sg;		/* Last sg element */
 	int b_count;				/* Bytes transferred from current entry */
 	struct scsi_cmnd *scsi_cmd;		/* SCSI command */
 	void (*done)(struct scsi_cmnd *);	/* Scsi completion routine */
@@ -173,12 +174,6 @@ static void idescsi_input_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigne
 	char *buf;
 
 	while (bcount) {
-		if (pc->sg - scsi_sglist(pc->scsi_cmd) >
-		                                 scsi_sg_count(pc->scsi_cmd)) {
-			printk (KERN_ERR "ide-scsi: scatter gather table too small, discarding data\n");
-			idescsi_discard_data (drive, bcount);
-			return;
-		}
 		count = min(pc->sg->length - pc->b_count, bcount);
 		if (PageHighMem(pc->sg->page)) {
 			unsigned long flags;
@@ -197,10 +192,17 @@ static void idescsi_input_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigne
 		}
 		bcount -= count; pc->b_count += count;
 		if (pc->b_count == pc->sg->length) {
-			pc->sg++;
+			if (pc->sg == pc->last_sg)
+				break;
+			pc->sg = sg_next(pc->sg);
 			pc->b_count = 0;
 		}
 	}
+
+	if (bcount) {
+		printk (KERN_ERR "ide-scsi: scatter gather table too small, discarding data\n");
+		idescsi_discard_data (drive, bcount);
+	}
 }
 
 static void idescsi_output_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigned int bcount)
@@ -209,12 +211,6 @@ static void idescsi_output_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsign
 	char *buf;
 
 	while (bcount) {
-		if (pc->sg - scsi_sglist(pc->scsi_cmd) >
-		                                 scsi_sg_count(pc->scsi_cmd)) {
-			printk (KERN_ERR "ide-scsi: scatter gather table too small, padding with zeros\n");
-			idescsi_output_zeros (drive, bcount);
-			return;
-		}
 		count = min(pc->sg->length - pc->b_count, bcount);
 		if (PageHighMem(pc->sg->page)) {
 			unsigned long flags;
@@ -233,10 +229,17 @@ static void idescsi_output_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsign
 		}
 		bcount -= count; pc->b_count += count;
 		if (pc->b_count == pc->sg->length) {
-			pc->sg++;
+			if (pc->sg == pc->last_sg)
+				break;
+			pc->sg = sg_next(pc->sg);
 			pc->b_count = 0;
 		}
 	}
+
+	if (bcount) {
+		printk (KERN_ERR "ide-scsi: scatter gather table too small, padding with zeros\n");
+		idescsi_output_zeros (drive, bcount);
+	}
 }
 
 static void hexdump(u8 *x, int len)
@@ -804,6 +807,7 @@ static int idescsi_queue (struct scsi_cmnd *cmd,
 	memcpy (pc->c, cmd->cmnd, cmd->cmd_len);
 	pc->buffer = NULL;
 	pc->sg = scsi_sglist(cmd);
+	pc->last_sg = sg_last(pc->sg, cmd->use_sg);
 	pc->b_count = 0;
 	pc->request_transfer = pc->buffer_size = scsi_bufflen(cmd);
 	pc->scsi_cmd = cmd;
diff --git a/drivers/scsi/initio.c b/drivers/scsi/initio.c
index d9dfb69ae031..22d40fd5845b 100644
--- a/drivers/scsi/initio.c
+++ b/drivers/scsi/initio.c
@@ -2831,6 +2831,7 @@ static struct scsi_host_template initio_template = {
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun		= 1,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 };
 
 static int initio_probe_one(struct pci_dev *pdev,
diff --git a/drivers/scsi/ips.c b/drivers/scsi/ips.c
index 2ed099e2c20d..edaac2714c5a 100644
--- a/drivers/scsi/ips.c
+++ b/drivers/scsi/ips.c
@@ -3252,7 +3252,7 @@ ips_done(ips_ha_t * ha, ips_scb_t * scb)
 		 */
 		if ((scb->breakup) || (scb->sg_break)) {
                         struct scatterlist *sg;
-                        int sg_dma_index, ips_sg_index = 0;
+                        int i, sg_dma_index, ips_sg_index = 0;
 
 			/* we had a data breakup */
 			scb->data_len = 0;
@@ -3261,20 +3261,22 @@ ips_done(ips_ha_t * ha, ips_scb_t * scb)
 
                         /* Spin forward to last dma chunk */
                         sg_dma_index = scb->breakup;
+                        for (i = 0; i < scb->breakup; i++)
+                                sg = sg_next(sg);
 
 			/* Take care of possible partial on last chunk */
                         ips_fill_scb_sg_single(ha,
-                                               sg_dma_address(&sg[sg_dma_index]),
+                                               sg_dma_address(sg),
                                                scb, ips_sg_index++,
-                                               sg_dma_len(&sg[sg_dma_index]));
+                                               sg_dma_len(sg));
 
                         for (; sg_dma_index < scsi_sg_count(scb->scsi_cmd);
-                             sg_dma_index++) {
+                             sg_dma_index++, sg = sg_next(sg)) {
                                 if (ips_fill_scb_sg_single
                                     (ha,
-                                     sg_dma_address(&sg[sg_dma_index]),
+                                     sg_dma_address(sg),
                                      scb, ips_sg_index++,
-                                     sg_dma_len(&sg[sg_dma_index])) < 0)
+                                     sg_dma_len(sg)) < 0)
                                         break;
                         }
 
diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index cd674938ccd5..c0755565fae9 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -1438,6 +1438,7 @@ struct scsi_host_template lpfc_template = {
 	.scan_finished		= lpfc_scan_finished,
 	.this_id		= -1,
 	.sg_tablesize		= LPFC_SG_SEG_CNT,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 	.cmd_per_lun		= LPFC_CMD_PER_LUN,
 	.use_clustering		= ENABLE_CLUSTERING,
 	.shost_attrs		= lpfc_hba_attrs,
@@ -1460,6 +1461,7 @@ struct scsi_host_template lpfc_vport_template = {
 	.sg_tablesize		= LPFC_SG_SEG_CNT,
 	.cmd_per_lun		= LPFC_CMD_PER_LUN,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 	.shost_attrs		= lpfc_vport_attrs,
 	.max_sectors		= 0xFFFF,
 };
diff --git a/drivers/scsi/mac53c94.c b/drivers/scsi/mac53c94.c
index b12ad7c7c673..a035001f4438 100644
--- a/drivers/scsi/mac53c94.c
+++ b/drivers/scsi/mac53c94.c
@@ -402,6 +402,7 @@ static struct scsi_host_template mac53c94_template = {
 	.sg_tablesize	= SG_ALL,
 	.cmd_per_lun	= 1,
 	.use_clustering	= DISABLE_CLUSTERING,
+	.use_sg_chaining = ENABLE_SG_CHAINING,
 };
 
 static int mac53c94_probe(struct macio_dev *mdev, const struct of_device_id *match)
diff --git a/drivers/scsi/megaraid.c b/drivers/scsi/megaraid.c
index e7e11f282c8f..10d1aff9938a 100644
--- a/drivers/scsi/megaraid.c
+++ b/drivers/scsi/megaraid.c
@@ -4492,6 +4492,7 @@ static struct scsi_host_template megaraid_template = {
 	.sg_tablesize			= MAX_SGLIST,
 	.cmd_per_lun			= DEF_CMD_PER_LUN,
 	.use_clustering			= ENABLE_CLUSTERING,
+	.use_sg_chaining		= ENABLE_SG_CHAINING,
 	.eh_abort_handler		= megaraid_abort,
 	.eh_device_reset_handler	= megaraid_reset,
 	.eh_bus_reset_handler		= megaraid_reset,
diff --git a/drivers/scsi/megaraid/megaraid_mbox.c b/drivers/scsi/megaraid/megaraid_mbox.c
index c6a53dccc16a..e4e4c6a39ed6 100644
--- a/drivers/scsi/megaraid/megaraid_mbox.c
+++ b/drivers/scsi/megaraid/megaraid_mbox.c
@@ -361,6 +361,7 @@ static struct scsi_host_template megaraid_template_g = {
 	.eh_host_reset_handler		= megaraid_reset_handler,
 	.change_queue_depth		= megaraid_change_queue_depth,
 	.use_clustering			= ENABLE_CLUSTERING,
+	.use_sg_chaining		= ENABLE_SG_CHAINING,
 	.sdev_attrs			= megaraid_sdev_attrs,
 	.shost_attrs			= megaraid_shost_attrs,
 };
diff --git a/drivers/scsi/megaraid/megaraid_sas.c b/drivers/scsi/megaraid/megaraid_sas.c
index ebb948c016bb..e3c5c5282203 100644
--- a/drivers/scsi/megaraid/megaraid_sas.c
+++ b/drivers/scsi/megaraid/megaraid_sas.c
@@ -1110,6 +1110,7 @@ static struct scsi_host_template megasas_template = {
 	.eh_timed_out = megasas_reset_timer,
 	.bios_param = megasas_bios_param,
 	.use_clustering = ENABLE_CLUSTERING,
+	.use_sg_chaining = ENABLE_SG_CHAINING,
 };
 
 /**
diff --git a/drivers/scsi/mesh.c b/drivers/scsi/mesh.c
index 651d09b08f2a..7470ff39ab22 100644
--- a/drivers/scsi/mesh.c
+++ b/drivers/scsi/mesh.c
@@ -1843,6 +1843,7 @@ static struct scsi_host_template mesh_template = {
 	.sg_tablesize			= SG_ALL,
 	.cmd_per_lun			= 2,
 	.use_clustering			= DISABLE_CLUSTERING,
+	.use_sg_chaining		= ENABLE_SG_CHAINING,
 };
 
 static int mesh_probe(struct macio_dev *mdev, const struct of_device_id *match)
diff --git a/drivers/scsi/nsp32.c b/drivers/scsi/nsp32.c
index 7fed35372150..28161dc95e0d 100644
--- a/drivers/scsi/nsp32.c
+++ b/drivers/scsi/nsp32.c
@@ -281,6 +281,7 @@ static struct scsi_host_template nsp32_template = {
 	.cmd_per_lun			= 1,
 	.this_id			= NSP32_HOST_SCSIID,
 	.use_clustering			= DISABLE_CLUSTERING,
+	.use_sg_chaining		= ENABLE_SG_CHAINING,
 	.eh_abort_handler       	= nsp32_eh_abort,
 	.eh_bus_reset_handler		= nsp32_eh_bus_reset,
 	.eh_host_reset_handler		= nsp32_eh_host_reset,
diff --git a/drivers/scsi/pcmcia/sym53c500_cs.c b/drivers/scsi/pcmcia/sym53c500_cs.c
index 961839ecfe86..190e2a7d7067 100644
--- a/drivers/scsi/pcmcia/sym53c500_cs.c
+++ b/drivers/scsi/pcmcia/sym53c500_cs.c
@@ -694,6 +694,7 @@ static struct scsi_host_template sym53c500_driver_template = {
      .sg_tablesize		= 32,
      .cmd_per_lun		= 1,
      .use_clustering		= ENABLE_CLUSTERING,
+     .use_sg_chaining		= ENABLE_SG_CHAINING,
      .shost_attrs		= SYM53C500_shost_attrs
 };
 
diff --git a/drivers/scsi/qla1280.c b/drivers/scsi/qla1280.c
index fba8aa8a81b5..76089cf55f4e 100644
--- a/drivers/scsi/qla1280.c
+++ b/drivers/scsi/qla1280.c
@@ -2775,7 +2775,7 @@ qla1280_64bit_start_scsi(struct scsi_qla_host *ha, struct srb * sp)
 	struct device_reg __iomem *reg = ha->iobase;
 	struct scsi_cmnd *cmd = sp->cmd;
 	cmd_a64_entry_t *pkt;
-	struct scatterlist *sg = NULL;
+	struct scatterlist *sg = NULL, *s;
 	__le32 *dword_ptr;
 	dma_addr_t dma_handle;
 	int status = 0;
@@ -2889,13 +2889,16 @@ qla1280_64bit_start_scsi(struct scsi_qla_host *ha, struct srb * sp)
 	 * Load data segments.
 	 */
 	if (seg_cnt) {	/* If data transfer. */
+		int remseg = seg_cnt;
 		/* Setup packet address segment pointer. */
 		dword_ptr = (u32 *)&pkt->dseg_0_address;
 
 		if (cmd->use_sg) {	/* If scatter gather */
 			/* Load command entry data segments. */
-			for (cnt = 0; cnt < 2 && seg_cnt; cnt++, seg_cnt--) {
-				dma_handle = sg_dma_address(sg);
+			for_each_sg(sg, s, seg_cnt, cnt) {
+				if (cnt == 2)
+					break;
+				dma_handle = sg_dma_address(s);
 #if defined(CONFIG_IA64_GENERIC) || defined(CONFIG_IA64_SGI_SN2)
 				if (ha->flags.use_pci_vchannel)
 					sn_pci_set_vchan(ha->pdev,
@@ -2906,12 +2909,12 @@ qla1280_64bit_start_scsi(struct scsi_qla_host *ha, struct srb * sp)
 					cpu_to_le32(pci_dma_lo32(dma_handle));
 				*dword_ptr++ =
 					cpu_to_le32(pci_dma_hi32(dma_handle));
-				*dword_ptr++ = cpu_to_le32(sg_dma_len(sg));
-				sg++;
+				*dword_ptr++ = cpu_to_le32(sg_dma_len(s));
 				dprintk(3, "S/G Segment phys_addr=%x %x, len=0x%x\n",
 					cpu_to_le32(pci_dma_hi32(dma_handle)),
 					cpu_to_le32(pci_dma_lo32(dma_handle)),
-					cpu_to_le32(sg_dma_len(sg)));
+					cpu_to_le32(sg_dma_len(sg_next(s))));
+				remseg--;
 			}
 			dprintk(5, "qla1280_64bit_start_scsi: Scatter/gather "
 				"command packet data - b %i, t %i, l %i \n",
@@ -2926,7 +2929,9 @@ qla1280_64bit_start_scsi(struct scsi_qla_host *ha, struct srb * sp)
 			dprintk(3, "S/G Building Continuation...seg_cnt=0x%x "
 				"remains\n", seg_cnt);
 
-			while (seg_cnt > 0) {
+			while (remseg > 0) {
+				/* Update sg start */
+				sg = s;
 				/* Adjust ring index. */
 				ha->req_ring_index++;
 				if (ha->req_ring_index == REQUEST_ENTRY_CNT) {
@@ -2952,9 +2957,10 @@ qla1280_64bit_start_scsi(struct scsi_qla_host *ha, struct srb * sp)
 					(u32 *)&((struct cont_a64_entry *) pkt)->dseg_0_address;
 
 				/* Load continuation entry data segments. */
-				for (cnt = 0; cnt < 5 && seg_cnt;
-				     cnt++, seg_cnt--) {
-					dma_handle = sg_dma_address(sg);
+				for_each_sg(sg, s, remseg, cnt) {
+					if (cnt == 5)
+						break;
+					dma_handle = sg_dma_address(s);
 #if defined(CONFIG_IA64_GENERIC) || defined(CONFIG_IA64_SGI_SN2)
 				if (ha->flags.use_pci_vchannel)
 					sn_pci_set_vchan(ha->pdev, 
@@ -2966,13 +2972,13 @@ qla1280_64bit_start_scsi(struct scsi_qla_host *ha, struct srb * sp)
 					*dword_ptr++ =
 						cpu_to_le32(pci_dma_hi32(dma_handle));
 					*dword_ptr++ =
-						cpu_to_le32(sg_dma_len(sg));
+						cpu_to_le32(sg_dma_len(s));
 					dprintk(3, "S/G Segment Cont. phys_addr=%x %x, len=0x%x\n",
 						cpu_to_le32(pci_dma_hi32(dma_handle)),
 						cpu_to_le32(pci_dma_lo32(dma_handle)),
-						cpu_to_le32(sg_dma_len(sg)));
-					sg++;
+						cpu_to_le32(sg_dma_len(s)));
 				}
+				remseg -= cnt;
 				dprintk(5, "qla1280_64bit_start_scsi: "
 					"continuation packet data - b %i, t "
 					"%i, l %i \n", SCSI_BUS_32(cmd),
@@ -3062,7 +3068,7 @@ qla1280_32bit_start_scsi(struct scsi_qla_host *ha, struct srb * sp)
 	struct device_reg __iomem *reg = ha->iobase;
 	struct scsi_cmnd *cmd = sp->cmd;
 	struct cmd_entry *pkt;
-	struct scatterlist *sg = NULL;
+	struct scatterlist *sg = NULL, *s;
 	__le32 *dword_ptr;
 	int status = 0;
 	int cnt;
@@ -3188,6 +3194,7 @@ qla1280_32bit_start_scsi(struct scsi_qla_host *ha, struct srb * sp)
 	 * Load data segments.
 	 */
 	if (seg_cnt) {
+		int remseg = seg_cnt;
 		/* Setup packet address segment pointer. */
 		dword_ptr = &pkt->dseg_0_address;
 
@@ -3196,22 +3203,25 @@ qla1280_32bit_start_scsi(struct scsi_qla_host *ha, struct srb * sp)
 			qla1280_dump_buffer(1, (char *)sg, 4 * 16);
 
 			/* Load command entry data segments. */
-			for (cnt = 0; cnt < 4 && seg_cnt; cnt++, seg_cnt--) {
+			for_each_sg(sg, s, seg_cnt, cnt) {
+				if (cnt == 4)
+					break;
 				*dword_ptr++ =
-					cpu_to_le32(pci_dma_lo32(sg_dma_address(sg)));
-				*dword_ptr++ =
-					cpu_to_le32(sg_dma_len(sg));
+					cpu_to_le32(pci_dma_lo32(sg_dma_address(s)));
+				*dword_ptr++ = cpu_to_le32(sg_dma_len(s));
 				dprintk(3, "S/G Segment phys_addr=0x%lx, len=0x%x\n",
-					(pci_dma_lo32(sg_dma_address(sg))),
-					(sg_dma_len(sg)));
-				sg++;
+					(pci_dma_lo32(sg_dma_address(s))),
+					(sg_dma_len(s)));
+				remseg--;
 			}
 			/*
 			 * Build continuation packets.
 			 */
 			dprintk(3, "S/G Building Continuation"
 				"...seg_cnt=0x%x remains\n", seg_cnt);
-			while (seg_cnt > 0) {
+			while (remseg > 0) {
+				/* Continue from end point */
+				sg = s;
 				/* Adjust ring index. */
 				ha->req_ring_index++;
 				if (ha->req_ring_index == REQUEST_ENTRY_CNT) {
@@ -3239,19 +3249,20 @@ qla1280_32bit_start_scsi(struct scsi_qla_host *ha, struct srb * sp)
 					&((struct cont_entry *) pkt)->dseg_0_address;
 
 				/* Load continuation entry data segments. */
-				for (cnt = 0; cnt < 7 && seg_cnt;
-				     cnt++, seg_cnt--) {
+				for_each_sg(sg, s, remseg, cnt) {
+					if (cnt == 7)
+						break;
 					*dword_ptr++ =
-						cpu_to_le32(pci_dma_lo32(sg_dma_address(sg)));
+						cpu_to_le32(pci_dma_lo32(sg_dma_address(s)));
 					*dword_ptr++ =
-						cpu_to_le32(sg_dma_len(sg));
+						cpu_to_le32(sg_dma_len(s));
 					dprintk(1,
 						"S/G Segment Cont. phys_addr=0x%x, "
 						"len=0x%x\n",
-						cpu_to_le32(pci_dma_lo32(sg_dma_address(sg))),
-						cpu_to_le32(sg_dma_len(sg)));
-					sg++;
+						cpu_to_le32(pci_dma_lo32(sg_dma_address(s))),
+						cpu_to_le32(sg_dma_len(s)));
 				}
+				remseg -= cnt;
 				dprintk(5, "qla1280_32bit_start_scsi: "
 					"continuation packet data - "
 					"scsi(%i:%i:%i)\n", SCSI_BUS_32(cmd),
@@ -4248,6 +4259,7 @@ static struct scsi_host_template qla1280_driver_template = {
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun		= 1,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 };
 
 
diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index a6bb8d0ecf13..0351d380c2d7 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -132,6 +132,7 @@ struct scsi_host_template qla2x00_driver_template = {
 	.this_id		= -1,
 	.cmd_per_lun		= 3,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 	.sg_tablesize		= SG_ALL,
 
 	/*
@@ -163,6 +164,7 @@ struct scsi_host_template qla24xx_driver_template = {
 	.this_id		= -1,
 	.cmd_per_lun		= 3,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 	.sg_tablesize		= SG_ALL,
 
 	.max_sectors		= 0xFFFF,
diff --git a/drivers/scsi/qla4xxx/ql4_os.c b/drivers/scsi/qla4xxx/ql4_os.c
index b1d565c12c5b..03b68d4f3bd0 100644
--- a/drivers/scsi/qla4xxx/ql4_os.c
+++ b/drivers/scsi/qla4xxx/ql4_os.c
@@ -94,6 +94,7 @@ static struct scsi_host_template qla4xxx_driver_template = {
 	.this_id		= -1,
 	.cmd_per_lun		= 3,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 	.sg_tablesize		= SG_ALL,
 
 	.max_sectors		= 0xFFFF,
diff --git a/drivers/scsi/qlogicfas.c b/drivers/scsi/qlogicfas.c
index 1e874f1fb5c6..1769f965eedf 100644
--- a/drivers/scsi/qlogicfas.c
+++ b/drivers/scsi/qlogicfas.c
@@ -197,6 +197,7 @@ static struct scsi_host_template qlogicfas_driver_template = {
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun		= 1,
 	.use_clustering		= DISABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 };
 
 static __init int qlogicfas_init(void)
diff --git a/drivers/scsi/qlogicpti.c b/drivers/scsi/qlogicpti.c
index e93f80316a19..7a2e7986b038 100644
--- a/drivers/scsi/qlogicpti.c
+++ b/drivers/scsi/qlogicpti.c
@@ -868,7 +868,7 @@ static inline int load_cmd(struct scsi_cmnd *Cmnd, struct Command_Entry *cmd,
 			   struct qlogicpti *qpti, u_int in_ptr, u_int out_ptr)
 {
 	struct dataseg *ds;
-	struct scatterlist *sg;
+	struct scatterlist *sg, *s;
 	int i, n;
 
 	if (Cmnd->use_sg) {
@@ -884,11 +884,12 @@ static inline int load_cmd(struct scsi_cmnd *Cmnd, struct Command_Entry *cmd,
 		n = sg_count;
 		if (n > 4)
 			n = 4;
-		for (i = 0; i < n; i++, sg++) {
-			ds[i].d_base = sg_dma_address(sg);
-			ds[i].d_count = sg_dma_len(sg);
+		for_each_sg(sg, s, n, i) {
+			ds[i].d_base = sg_dma_address(s);
+			ds[i].d_count = sg_dma_len(s);
 		}
 		sg_count -= 4;
+		sg = s;
 		while (sg_count > 0) {
 			struct Continuation_Entry *cont;
 
@@ -907,9 +908,9 @@ static inline int load_cmd(struct scsi_cmnd *Cmnd, struct Command_Entry *cmd,
 			n = sg_count;
 			if (n > 7)
 				n = 7;
-			for (i = 0; i < n; i++, sg++) {
-				ds[i].d_base = sg_dma_address(sg);
-				ds[i].d_count = sg_dma_len(sg);
+			for_each_sg(sg, s, n, i) {
+				ds[i].d_base = sg_dma_address(s);
+				ds[i].d_count = sg_dma_len(s);
 			}
 			sg_count -= n;
 		}
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 4947dfe625a6..72ee4c9cfb1a 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -38,6 +38,7 @@
 #include <linux/proc_fs.h>
 #include <linux/vmalloc.h>
 #include <linux/moduleparam.h>
+#include <linux/scatterlist.h>
 
 #include <linux/blkdev.h>
 #include "scsi.h"
@@ -600,7 +601,7 @@ static int fill_from_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
 	int k, req_len, act_len, len, active;
 	void * kaddr;
 	void * kaddr_off;
-	struct scatterlist * sgpnt;
+	struct scatterlist * sg;
 
 	if (0 == scp->request_bufflen)
 		return 0;
@@ -619,16 +620,16 @@ static int fill_from_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
 			scp->resid = req_len - act_len;
 		return 0;
 	}
-	sgpnt = (struct scatterlist *)scp->request_buffer;
 	active = 1;
-	for (k = 0, req_len = 0, act_len = 0; k < scp->use_sg; ++k, ++sgpnt) {
+	req_len = act_len = 0;
+	scsi_for_each_sg(scp, sg, scp->use_sg, k) {
 		if (active) {
 			kaddr = (unsigned char *)
-				kmap_atomic(sgpnt->page, KM_USER0);
+				kmap_atomic(sg->page, KM_USER0);
 			if (NULL == kaddr)
 				return (DID_ERROR << 16);
-			kaddr_off = (unsigned char *)kaddr + sgpnt->offset;
-			len = sgpnt->length;
+			kaddr_off = (unsigned char *)kaddr + sg->offset;
+			len = sg->length;
 			if ((req_len + len) > arr_len) {
 				active = 0;
 				len = arr_len - req_len;
@@ -637,7 +638,7 @@ static int fill_from_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
 			kunmap_atomic(kaddr, KM_USER0);
 			act_len += len;
 		}
-		req_len += sgpnt->length;
+		req_len += sg->length;
 	}
 	if (scp->resid)
 		scp->resid -= act_len;
@@ -653,7 +654,7 @@ static int fetch_to_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
 	int k, req_len, len, fin;
 	void * kaddr;
 	void * kaddr_off;
-	struct scatterlist * sgpnt;
+	struct scatterlist * sg;
 
 	if (0 == scp->request_bufflen)
 		return 0;
@@ -668,13 +669,14 @@ static int fetch_to_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
 		memcpy(arr, scp->request_buffer, len);
 		return len;
 	}
-	sgpnt = (struct scatterlist *)scp->request_buffer;
-	for (k = 0, req_len = 0, fin = 0; k < scp->use_sg; ++k, ++sgpnt) {
-		kaddr = (unsigned char *)kmap_atomic(sgpnt->page, KM_USER0);
+	sg = scsi_sglist(scp);
+	req_len = fin = 0;
+	for (k = 0; k < scp->use_sg; ++k, sg = sg_next(sg)) {
+		kaddr = (unsigned char *)kmap_atomic(sg->page, KM_USER0);
 		if (NULL == kaddr)
 			return -1;
-		kaddr_off = (unsigned char *)kaddr + sgpnt->offset;
-		len = sgpnt->length;
+		kaddr_off = (unsigned char *)kaddr + sg->offset;
+		len = sg->length;
 		if ((req_len + len) > max_arr_len) {
 			len = max_arr_len - req_len;
 			fin = 1;
@@ -683,7 +685,7 @@ static int fetch_to_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
 		kunmap_atomic(kaddr, KM_USER0);
 		if (fin)
 			return req_len + len;
-		req_len += sgpnt->length;
+		req_len += sg->length;
 	}
 	return req_len;
 }
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 207f1aa08869..aac8a02cbe80 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -17,6 +17,7 @@
 #include <linux/pci.h>
 #include <linux/delay.h>
 #include <linux/hardirq.h>
+#include <linux/scatterlist.h>
 
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
@@ -33,35 +34,34 @@
 #define SG_MEMPOOL_NR		ARRAY_SIZE(scsi_sg_pools)
 #define SG_MEMPOOL_SIZE		2
 
+/*
+ * The maximum number of SG segments that we will put inside a scatterlist
+ * (unless chaining is used). Should ideally fit inside a single page, to
+ * avoid a higher order allocation.
+ */
+#define SCSI_MAX_SG_SEGMENTS	128
+
 struct scsi_host_sg_pool {
 	size_t		size;
-	char		*name; 
+	char		*name;
 	struct kmem_cache	*slab;
 	mempool_t	*pool;
 };
 
-#if (SCSI_MAX_PHYS_SEGMENTS < 32)
-#error SCSI_MAX_PHYS_SEGMENTS is too small
-#endif
-
-#define SP(x) { x, "sgpool-" #x } 
+#define SP(x) { x, "sgpool-" #x }
 static struct scsi_host_sg_pool scsi_sg_pools[] = {
 	SP(8),
 	SP(16),
+#if (SCSI_MAX_SG_SEGMENTS > 16)
 	SP(32),
-#if (SCSI_MAX_PHYS_SEGMENTS > 32)
+#if (SCSI_MAX_SG_SEGMENTS > 32)
 	SP(64),
-#if (SCSI_MAX_PHYS_SEGMENTS > 64)
+#if (SCSI_MAX_SG_SEGMENTS > 64)
 	SP(128),
-#if (SCSI_MAX_PHYS_SEGMENTS > 128)
-	SP(256),
-#if (SCSI_MAX_PHYS_SEGMENTS > 256)
-#error SCSI_MAX_PHYS_SEGMENTS is too large
-#endif
 #endif
 #endif
 #endif
-}; 	
+};
 #undef SP
 
 static void scsi_run_queue(struct request_queue *q);
@@ -289,14 +289,16 @@ static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
 	struct request_queue *q = rq->q;
 	int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	unsigned int data_len = bufflen, len, bytes, off;
+	struct scatterlist *sg;
 	struct page *page;
 	struct bio *bio = NULL;
 	int i, err, nr_vecs = 0;
 
-	for (i = 0; i < nsegs; i++) {
-		page = sgl[i].page;
-		off = sgl[i].offset;
-		len = sgl[i].length;
+	for_each_sg(sgl, sg, nsegs, i) {
+		page = sg->page;
+		off = sg->offset;
+		len = sg->length;
+ 		data_len += len;
 
 		while (len > 0 && data_len > 0) {
 			/*
@@ -695,56 +697,170 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate,
 	return NULL;
 }
 
-struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
-{
-	struct scsi_host_sg_pool *sgp;
-	struct scatterlist *sgl;
+/*
+ * Like SCSI_MAX_SG_SEGMENTS, but for archs that have sg chaining. This limit
+ * is totally arbitrary, a setting of 2048 will get you at least 8mb ios.
+ */
+#define SCSI_MAX_SG_CHAIN_SEGMENTS	2048
 
-	BUG_ON(!cmd->use_sg);
+static inline unsigned int scsi_sgtable_index(unsigned short nents)
+{
+	unsigned int index;
 
-	switch (cmd->use_sg) {
+	switch (nents) {
 	case 1 ... 8:
-		cmd->sglist_len = 0;
+		index = 0;
 		break;
 	case 9 ... 16:
-		cmd->sglist_len = 1;
+		index = 1;
 		break;
+#if (SCSI_MAX_SG_SEGMENTS > 16)
 	case 17 ... 32:
-		cmd->sglist_len = 2;
+		index = 2;
 		break;
-#if (SCSI_MAX_PHYS_SEGMENTS > 32)
+#if (SCSI_MAX_SG_SEGMENTS > 32)
 	case 33 ... 64:
-		cmd->sglist_len = 3;
+		index = 3;
 		break;
-#if (SCSI_MAX_PHYS_SEGMENTS > 64)
+#if (SCSI_MAX_SG_SEGMENTS > 64)
 	case 65 ... 128:
-		cmd->sglist_len = 4;
-		break;
-#if (SCSI_MAX_PHYS_SEGMENTS  > 128)
-	case 129 ... 256:
-		cmd->sglist_len = 5;
+		index = 4;
 		break;
 #endif
 #endif
 #endif
 	default:
-		return NULL;
+		printk(KERN_ERR "scsi: bad segment count=%d\n", nents);
+		BUG();
 	}
 
-	sgp = scsi_sg_pools + cmd->sglist_len;
-	sgl = mempool_alloc(sgp->pool, gfp_mask);
-	return sgl;
+	return index;
+}
+
+struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
+{
+	struct scsi_host_sg_pool *sgp;
+	struct scatterlist *sgl, *prev, *ret;
+	unsigned int index;
+	int this, left;
+
+	BUG_ON(!cmd->use_sg);
+
+	left = cmd->use_sg;
+	ret = prev = NULL;
+	do {
+		this = left;
+		if (this > SCSI_MAX_SG_SEGMENTS) {
+			this = SCSI_MAX_SG_SEGMENTS - 1;
+			index = SG_MEMPOOL_NR - 1;
+		} else
+			index = scsi_sgtable_index(this);
+
+		left -= this;
+
+		sgp = scsi_sg_pools + index;
+
+		sgl = mempool_alloc(sgp->pool, gfp_mask);
+		if (unlikely(!sgl))
+			goto enomem;
+
+		memset(sgl, 0, sizeof(*sgl) * sgp->size);
+
+		/*
+		 * first loop through, set initial index and return value
+		 */
+		if (!ret)
+			ret = sgl;
+
+		/*
+		 * chain previous sglist, if any. we know the previous
+		 * sglist must be the biggest one, or we would not have
+		 * ended up doing another loop.
+		 */
+		if (prev)
+			sg_chain(prev, SCSI_MAX_SG_SEGMENTS, sgl);
+
+		/*
+		 * don't allow subsequent mempool allocs to sleep, it would
+		 * violate the mempool principle.
+		 */
+		gfp_mask &= ~__GFP_WAIT;
+		gfp_mask |= __GFP_HIGH;
+		prev = sgl;
+	} while (left);
+
+	/*
+	 * ->use_sg may get modified after dma mapping has potentially
+	 * shrunk the number of segments, so keep a copy of it for free.
+	 */
+	cmd->__use_sg = cmd->use_sg;
+	return ret;
+enomem:
+	if (ret) {
+		/*
+		 * Free entries chained off ret. Since we were trying to
+		 * allocate another sglist, we know that all entries are of
+		 * the max size.
+		 */
+		sgp = scsi_sg_pools + SG_MEMPOOL_NR - 1;
+		prev = ret;
+		ret = &ret[SCSI_MAX_SG_SEGMENTS - 1];
+
+		while ((sgl = sg_chain_ptr(ret)) != NULL) {
+			ret = &sgl[SCSI_MAX_SG_SEGMENTS - 1];
+			mempool_free(sgl, sgp->pool);
+		}
+
+		mempool_free(prev, sgp->pool);
+	}
+	return NULL;
 }
 
 EXPORT_SYMBOL(scsi_alloc_sgtable);
 
-void scsi_free_sgtable(struct scatterlist *sgl, int index)
+void scsi_free_sgtable(struct scsi_cmnd *cmd)
 {
+	struct scatterlist *sgl = cmd->request_buffer;
 	struct scsi_host_sg_pool *sgp;
 
-	BUG_ON(index >= SG_MEMPOOL_NR);
+	/*
+	 * if this is the biggest size sglist, check if we have
+	 * chained parts we need to free
+	 */
+	if (cmd->__use_sg > SCSI_MAX_SG_SEGMENTS) {
+		unsigned short this, left;
+		struct scatterlist *next;
+		unsigned int index;
+
+		left = cmd->__use_sg - (SCSI_MAX_SG_SEGMENTS - 1);
+		next = sg_chain_ptr(&sgl[SCSI_MAX_SG_SEGMENTS - 1]);
+		while (left && next) {
+			sgl = next;
+			this = left;
+			if (this > SCSI_MAX_SG_SEGMENTS) {
+				this = SCSI_MAX_SG_SEGMENTS - 1;
+				index = SG_MEMPOOL_NR - 1;
+			} else
+				index = scsi_sgtable_index(this);
+
+			left -= this;
+
+			sgp = scsi_sg_pools + index;
+
+			if (left)
+				next = sg_chain_ptr(&sgl[sgp->size - 1]);
+
+			mempool_free(sgl, sgp->pool);
+		}
+
+		/*
+		 * Restore original, will be freed below
+		 */
+		sgl = cmd->request_buffer;
+		sgp = scsi_sg_pools + SG_MEMPOOL_NR - 1;
+	} else
+		sgp = scsi_sg_pools + scsi_sgtable_index(cmd->__use_sg);
 
-	sgp = scsi_sg_pools + index;
 	mempool_free(sgl, sgp->pool);
 }
 
@@ -770,7 +886,7 @@ EXPORT_SYMBOL(scsi_free_sgtable);
 static void scsi_release_buffers(struct scsi_cmnd *cmd)
 {
 	if (cmd->use_sg)
-		scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len);
+		scsi_free_sgtable(cmd);
 
 	/*
 	 * Zero these out.  They now point to freed memory, and it is
@@ -984,7 +1100,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
 static int scsi_init_io(struct scsi_cmnd *cmd)
 {
 	struct request     *req = cmd->request;
-	struct scatterlist *sgpnt;
 	int		   count;
 
 	/*
@@ -997,14 +1112,13 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
 	/*
 	 * If sg table allocation fails, requeue request later.
 	 */
-	sgpnt = scsi_alloc_sgtable(cmd, GFP_ATOMIC);
-	if (unlikely(!sgpnt)) {
+	cmd->request_buffer = scsi_alloc_sgtable(cmd, GFP_ATOMIC);
+	if (unlikely(!cmd->request_buffer)) {
 		scsi_unprep_request(req);
 		return BLKPREP_DEFER;
 	}
 
 	req->buffer = NULL;
-	cmd->request_buffer = (char *) sgpnt;
 	if (blk_pc_request(req))
 		cmd->request_bufflen = req->data_len;
 	else
@@ -1529,8 +1643,25 @@ struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
 	if (!q)
 		return NULL;
 
+	/*
+	 * this limit is imposed by hardware restrictions
+	 */
 	blk_queue_max_hw_segments(q, shost->sg_tablesize);
-	blk_queue_max_phys_segments(q, SCSI_MAX_PHYS_SEGMENTS);
+
+	/*
+	 * In the future, sg chaining support will be mandatory and this
+	 * ifdef can then go away. Right now we don't have all archs
+	 * converted, so better keep it safe.
+	 */
+#ifdef ARCH_HAS_SG_CHAIN
+	if (shost->use_sg_chaining)
+		blk_queue_max_phys_segments(q, SCSI_MAX_SG_CHAIN_SEGMENTS);
+	else
+		blk_queue_max_phys_segments(q, SCSI_MAX_SG_SEGMENTS);
+#else
+	blk_queue_max_phys_segments(q, SCSI_MAX_SG_SEGMENTS);
+#endif
+
 	blk_queue_max_sectors(q, shost->max_sectors);
 	blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
 	blk_queue_segment_boundary(q, shost->dma_boundary);
@@ -2193,18 +2324,19 @@ EXPORT_SYMBOL_GPL(scsi_target_unblock);
  *
  * Returns virtual address of the start of the mapped page
  */
-void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
+void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
 			  size_t *offset, size_t *len)
 {
 	int i;
 	size_t sg_len = 0, len_complete = 0;
+	struct scatterlist *sg;
 	struct page *page;
 
 	WARN_ON(!irqs_disabled());
 
-	for (i = 0; i < sg_count; i++) {
+	for_each_sg(sgl, sg, sg_count, i) {
 		len_complete = sg_len; /* Complete sg-entries */
-		sg_len += sg[i].length;
+		sg_len += sg->length;
 		if (sg_len > *offset)
 			break;
 	}
@@ -2218,10 +2350,10 @@ void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
 	}
 
 	/* Offset starting from the beginning of first page in this sg-entry */
-	*offset = *offset - len_complete + sg[i].offset;
+	*offset = *offset - len_complete + sg->offset;
 
 	/* Assumption: contiguous pages can be accessed as "page + i" */
-	page = nth_page(sg[i].page, (*offset >> PAGE_SHIFT));
+	page = nth_page(sg->page, (*offset >> PAGE_SHIFT));
 	*offset &= ~PAGE_MASK;
 
 	/* Bytes in this sg-entry from *offset to the end of the page */
diff --git a/drivers/scsi/scsi_tgt_lib.c b/drivers/scsi/scsi_tgt_lib.c
index 66c692ffa305..a91761c3645f 100644
--- a/drivers/scsi/scsi_tgt_lib.c
+++ b/drivers/scsi/scsi_tgt_lib.c
@@ -332,7 +332,7 @@ static void scsi_tgt_cmd_done(struct scsi_cmnd *cmd)
 	scsi_tgt_uspace_send_status(cmd, tcmd->itn_id, tcmd->tag);
 
 	if (cmd->request_buffer)
-		scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len);
+		scsi_free_sgtable(cmd);
 
 	queue_work(scsi_tgtd, &tcmd->work);
 }
@@ -373,7 +373,7 @@ static int scsi_tgt_init_cmd(struct scsi_cmnd *cmd, gfp_t gfp_mask)
 	}
 
 	eprintk("cmd %p cnt %d\n", cmd, cmd->use_sg);
-	scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len);
+	scsi_free_sgtable(cmd);
 	return -EINVAL;
 }
 
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 0a3a528212c2..69f542c4923c 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -826,27 +826,6 @@ static int sd_sync_cache(struct scsi_disk *sdkp)
 	return 0;
 }
 
-static int sd_issue_flush(struct request_queue *q, struct gendisk *disk,
-			  sector_t *error_sector)
-{
-	int ret = 0;
-	struct scsi_device *sdp = q->queuedata;
-	struct scsi_disk *sdkp;
-
-	if (sdp->sdev_state != SDEV_RUNNING)
-		return -ENXIO;
-
-	sdkp = scsi_disk_get_from_dev(&sdp->sdev_gendev);
-
-	if (!sdkp)
-               return -ENODEV;
-
-	if (sdkp->WCE)
-		ret = sd_sync_cache(sdkp);
-	scsi_disk_put(sdkp);
-	return ret;
-}
-
 static void sd_prepare_flush(struct request_queue *q, struct request *rq)
 {
 	memset(rq->cmd, 0, sizeof(rq->cmd));
@@ -1697,7 +1676,6 @@ static int sd_probe(struct device *dev)
 	sd_revalidate_disk(gd);
 
 	blk_queue_prep_rq(sdp->request_queue, sd_prep_fn);
-	blk_queue_issue_flush_fn(sdp->request_queue, sd_issue_flush);
 
 	gd->driverfs_dev = &sdp->sdev_gendev;
 	gd->flags = GENHD_FL_DRIVERFS;
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index f6f5fc7d0cee..7238b2dfc497 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1165,7 +1165,7 @@ sg_vma_nopage(struct vm_area_struct *vma, unsigned long addr, int *type)
 	sg = rsv_schp->buffer;
 	sa = vma->vm_start;
 	for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end);
-	     ++k, ++sg) {
+	     ++k, sg = sg_next(sg)) {
 		len = vma->vm_end - sa;
 		len = (len < sg->length) ? len : sg->length;
 		if (offset < len) {
@@ -1209,7 +1209,7 @@ sg_mmap(struct file *filp, struct vm_area_struct *vma)
 	sa = vma->vm_start;
 	sg = rsv_schp->buffer;
 	for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end);
-	     ++k, ++sg) {
+	     ++k, sg = sg_next(sg)) {
 		len = vma->vm_end - sa;
 		len = (len < sg->length) ? len : sg->length;
 		sa += len;
@@ -1840,7 +1840,7 @@ sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
 	}
 	for (k = 0, sg = schp->buffer, rem_sz = blk_size;
 	     (rem_sz > 0) && (k < mx_sc_elems);
-	     ++k, rem_sz -= ret_sz, ++sg) {
+	     ++k, rem_sz -= ret_sz, sg = sg_next(sg)) {
 		
 		num = (rem_sz > scatter_elem_sz_prev) ?
 		      scatter_elem_sz_prev : rem_sz;
@@ -1913,7 +1913,7 @@ sg_write_xfer(Sg_request * srp)
 		if (res)
 			return res;
 
-		for (; p; ++sg, ksglen = sg->length,
+		for (; p; sg = sg_next(sg), ksglen = sg->length,
 		     p = page_address(sg->page)) {
 			if (usglen <= 0)
 				break;
@@ -1992,7 +1992,7 @@ sg_remove_scat(Sg_scatter_hold * schp)
 			int k;
 
 			for (k = 0; (k < schp->k_use_sg) && sg->page;
-			     ++k, ++sg) {
+			     ++k, sg = sg_next(sg)) {
 				SCSI_LOG_TIMEOUT(5, printk(
 				    "sg_remove_scat: k=%d, pg=0x%p, len=%d\n",
 				    k, sg->page, sg->length));
@@ -2045,7 +2045,7 @@ sg_read_xfer(Sg_request * srp)
 		if (res)
 			return res;
 
-		for (; p; ++sg, ksglen = sg->length,
+		for (; p; sg = sg_next(sg), ksglen = sg->length,
 		     p = page_address(sg->page)) {
 			if (usglen <= 0)
 				break;
@@ -2092,7 +2092,7 @@ sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
 	if ((!outp) || (num_read_xfer <= 0))
 		return 0;
 
-	for (k = 0; (k < schp->k_use_sg) && sg->page; ++k, ++sg) {
+	for (k = 0; (k < schp->k_use_sg) && sg->page; ++k, sg = sg_next(sg)) {
 		num = sg->length;
 		if (num > num_read_xfer) {
 			if (__copy_to_user(outp, page_address(sg->page),
@@ -2142,7 +2142,7 @@ sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
 	SCSI_LOG_TIMEOUT(4, printk("sg_link_reserve: size=%d\n", size));
 	rem = size;
 
-	for (k = 0; k < rsv_schp->k_use_sg; ++k, ++sg) {
+	for (k = 0; k < rsv_schp->k_use_sg; ++k, sg = sg_next(sg)) {
 		num = sg->length;
 		if (rem <= num) {
 			sfp->save_scat_len = num;
diff --git a/drivers/scsi/stex.c b/drivers/scsi/stex.c
index 72f6d8015358..e3fab3a6aed7 100644
--- a/drivers/scsi/stex.c
+++ b/drivers/scsi/stex.c
@@ -1123,6 +1123,7 @@ static struct scsi_host_template driver_template = {
 	.this_id			= -1,
 	.sg_tablesize			= ST_MAX_SG,
 	.cmd_per_lun			= ST_CMD_PER_LUN,
+	.use_sg_chaining		= ENABLE_SG_CHAINING,
 };
 
 static int stex_set_dma_mask(struct pci_dev * pdev)
diff --git a/drivers/scsi/sym53c416.c b/drivers/scsi/sym53c416.c
index 92bfaeafe30d..8befab7e9839 100644
--- a/drivers/scsi/sym53c416.c
+++ b/drivers/scsi/sym53c416.c
@@ -854,5 +854,6 @@ static struct scsi_host_template driver_template = {
 	.cmd_per_lun =		1,
 	.unchecked_isa_dma =	1,
 	.use_clustering =	ENABLE_CLUSTERING,
+	.use_sg_chaining =	ENABLE_SG_CHAINING,
 };
 #include "scsi_module.c"
diff --git a/drivers/scsi/sym53c8xx_2/sym_glue.c b/drivers/scsi/sym53c8xx_2/sym_glue.c
index 3db22325ea2c..db03c4c8ec1e 100644
--- a/drivers/scsi/sym53c8xx_2/sym_glue.c
+++ b/drivers/scsi/sym53c8xx_2/sym_glue.c
@@ -1808,6 +1808,7 @@ static struct scsi_host_template sym2_template = {
 	.eh_host_reset_handler	= sym53c8xx_eh_host_reset_handler,
 	.this_id		= 7,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 	.max_sectors		= 0xFFFF,
 #ifdef SYM_LINUX_PROC_INFO_SUPPORT
 	.proc_info		= sym53c8xx_proc_info,
diff --git a/drivers/scsi/u14-34f.c b/drivers/scsi/u14-34f.c
index fc9f51818e8f..7edd6ceb13b2 100644
--- a/drivers/scsi/u14-34f.c
+++ b/drivers/scsi/u14-34f.c
@@ -450,7 +450,8 @@ static struct scsi_host_template driver_template = {
                 .slave_configure         = u14_34f_slave_configure,
                 .this_id                 = 7,
                 .unchecked_isa_dma       = 1,
-                .use_clustering          = ENABLE_CLUSTERING
+                .use_clustering          = ENABLE_CLUSTERING,
+                .use_sg_chaining         = ENABLE_SG_CHAINING,
                 };
 
 #if !defined(__BIG_ENDIAN_BITFIELD) && !defined(__LITTLE_ENDIAN_BITFIELD)
diff --git a/drivers/scsi/ultrastor.c b/drivers/scsi/ultrastor.c
index c08235d5afc9..ea72bbeb8f9d 100644
--- a/drivers/scsi/ultrastor.c
+++ b/drivers/scsi/ultrastor.c
@@ -1197,5 +1197,6 @@ static struct scsi_host_template driver_template = {
 	.cmd_per_lun       = ULTRASTOR_MAX_CMDS_PER_LUN,
 	.unchecked_isa_dma = 1,
 	.use_clustering    = ENABLE_CLUSTERING,
+	.use_sg_chaining   = ENABLE_SG_CHAINING,
 };
 #include "scsi_module.c"
diff --git a/drivers/scsi/wd7000.c b/drivers/scsi/wd7000.c
index d6fd4259c56b..255c611e78b8 100644
--- a/drivers/scsi/wd7000.c
+++ b/drivers/scsi/wd7000.c
@@ -1671,6 +1671,7 @@ static struct scsi_host_template driver_template = {
 	.cmd_per_lun		= 1,
 	.unchecked_isa_dma	= 1,
 	.use_clustering		= ENABLE_CLUSTERING,
+	.use_sg_chaining	= ENABLE_SG_CHAINING,
 };
 
 #include "scsi_module.c"
diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
index 4d3cbb12b713..8d3711a7ff06 100644
--- a/drivers/usb/storage/alauda.c
+++ b/drivers/usb/storage/alauda.c
@@ -798,12 +798,13 @@ static int alauda_read_data(struct us_data *us, unsigned long address,
 {
 	unsigned char *buffer;
 	u16 lba, max_lba;
-	unsigned int page, len, index, offset;
+	unsigned int page, len, offset;
 	unsigned int blockshift = MEDIA_INFO(us).blockshift;
 	unsigned int pageshift = MEDIA_INFO(us).pageshift;
 	unsigned int blocksize = MEDIA_INFO(us).blocksize;
 	unsigned int pagesize = MEDIA_INFO(us).pagesize;
 	unsigned int uzonesize = MEDIA_INFO(us).uzonesize;
+	struct scatterlist *sg;
 	int result;
 
 	/*
@@ -827,7 +828,8 @@ static int alauda_read_data(struct us_data *us, unsigned long address,
 	max_lba = MEDIA_INFO(us).capacity >> (blockshift + pageshift);
 
 	result = USB_STOR_TRANSPORT_GOOD;
-	index = offset = 0;
+	offset = 0;
+	sg = NULL;
 
 	while (sectors > 0) {
 		unsigned int zone = lba / uzonesize; /* integer division */
@@ -873,7 +875,7 @@ static int alauda_read_data(struct us_data *us, unsigned long address,
 
 		/* Store the data in the transfer buffer */
 		usb_stor_access_xfer_buf(buffer, len, us->srb,
-				&index, &offset, TO_XFER_BUF);
+				&sg, &offset, TO_XFER_BUF);
 
 		page = 0;
 		lba++;
@@ -891,11 +893,12 @@ static int alauda_write_data(struct us_data *us, unsigned long address,
 		unsigned int sectors)
 {
 	unsigned char *buffer, *blockbuffer;
-	unsigned int page, len, index, offset;
+	unsigned int page, len, offset;
 	unsigned int blockshift = MEDIA_INFO(us).blockshift;
 	unsigned int pageshift = MEDIA_INFO(us).pageshift;
 	unsigned int blocksize = MEDIA_INFO(us).blocksize;
 	unsigned int pagesize = MEDIA_INFO(us).pagesize;
+	struct scatterlist *sg;
 	u16 lba, max_lba;
 	int result;
 
@@ -929,7 +932,8 @@ static int alauda_write_data(struct us_data *us, unsigned long address,
 	max_lba = MEDIA_INFO(us).capacity >> (pageshift + blockshift);
 
 	result = USB_STOR_TRANSPORT_GOOD;
-	index = offset = 0;
+	offset = 0;
+	sg = NULL;
 
 	while (sectors > 0) {
 		/* Write as many sectors as possible in this block */
@@ -946,7 +950,7 @@ static int alauda_write_data(struct us_data *us, unsigned long address,
 
 		/* Get the data from the transfer buffer */
 		usb_stor_access_xfer_buf(buffer, len, us->srb,
-				&index, &offset, FROM_XFER_BUF);
+				&sg, &offset, FROM_XFER_BUF);
 
 		result = alauda_write_lba(us, lba, page, pages, buffer,
 			blockbuffer);
diff --git a/drivers/usb/storage/datafab.c b/drivers/usb/storage/datafab.c
index c87ad1bae1d6..579e9f52053a 100644
--- a/drivers/usb/storage/datafab.c
+++ b/drivers/usb/storage/datafab.c
@@ -98,7 +98,8 @@ static int datafab_read_data(struct us_data *us,
 	unsigned char  thistime;
 	unsigned int totallen, alloclen;
 	int len, result;
-	unsigned int sg_idx = 0, sg_offset = 0;
+	unsigned int sg_offset = 0;
+	struct scatterlist *sg = NULL;
 
 	// we're working in LBA mode.  according to the ATA spec, 
 	// we can support up to 28-bit addressing.  I don't know if Datafab
@@ -155,7 +156,7 @@ static int datafab_read_data(struct us_data *us,
 
 		// Store the data in the transfer buffer
 		usb_stor_access_xfer_buf(buffer, len, us->srb,
-				 &sg_idx, &sg_offset, TO_XFER_BUF);
+				 &sg, &sg_offset, TO_XFER_BUF);
 
 		sector += thistime;
 		totallen -= len;
@@ -181,7 +182,8 @@ static int datafab_write_data(struct us_data *us,
 	unsigned char thistime;
 	unsigned int totallen, alloclen;
 	int len, result;
-	unsigned int sg_idx = 0, sg_offset = 0;
+	unsigned int sg_offset = 0;
+	struct scatterlist *sg = NULL;
 
 	// we're working in LBA mode.  according to the ATA spec, 
 	// we can support up to 28-bit addressing.  I don't know if Datafab
@@ -217,7 +219,7 @@ static int datafab_write_data(struct us_data *us,
 
 		// Get the data from the transfer buffer
 		usb_stor_access_xfer_buf(buffer, len, us->srb,
-				&sg_idx, &sg_offset, FROM_XFER_BUF);
+				&sg, &sg_offset, FROM_XFER_BUF);
 
 		command[0] = 0;
 		command[1] = thistime;
diff --git a/drivers/usb/storage/jumpshot.c b/drivers/usb/storage/jumpshot.c
index 003fcf545888..61097cbb1585 100644
--- a/drivers/usb/storage/jumpshot.c
+++ b/drivers/usb/storage/jumpshot.c
@@ -119,7 +119,8 @@ static int jumpshot_read_data(struct us_data *us,
 	unsigned char  thistime;
 	unsigned int totallen, alloclen;
 	int len, result;
-	unsigned int sg_idx = 0, sg_offset = 0;
+	unsigned int sg_offset = 0;
+	struct scatterlist *sg = NULL;
 
 	// we're working in LBA mode.  according to the ATA spec, 
 	// we can support up to 28-bit addressing.  I don't know if Jumpshot
@@ -170,7 +171,7 @@ static int jumpshot_read_data(struct us_data *us,
 
 		// Store the data in the transfer buffer
 		usb_stor_access_xfer_buf(buffer, len, us->srb,
-				 &sg_idx, &sg_offset, TO_XFER_BUF);
+				 &sg, &sg_offset, TO_XFER_BUF);
 
 		sector += thistime;
 		totallen -= len;
@@ -195,7 +196,8 @@ static int jumpshot_write_data(struct us_data *us,
 	unsigned char  thistime;
 	unsigned int totallen, alloclen;
 	int len, result, waitcount;
-	unsigned int sg_idx = 0, sg_offset = 0;
+	unsigned int sg_offset = 0;
+	struct scatterlist *sg = NULL;
 
 	// we're working in LBA mode.  according to the ATA spec, 
 	// we can support up to 28-bit addressing.  I don't know if Jumpshot
@@ -225,7 +227,7 @@ static int jumpshot_write_data(struct us_data *us,
 
 		// Get the data from the transfer buffer
 		usb_stor_access_xfer_buf(buffer, len, us->srb,
-				&sg_idx, &sg_offset, FROM_XFER_BUF);
+				&sg, &sg_offset, FROM_XFER_BUF);
 
 		command[0] = 0;
 		command[1] = thistime;
diff --git a/drivers/usb/storage/protocol.c b/drivers/usb/storage/protocol.c
index 9ad30428d2dd..cc8f7c52c729 100644
--- a/drivers/usb/storage/protocol.c
+++ b/drivers/usb/storage/protocol.c
@@ -157,7 +157,7 @@ void usb_stor_transparent_scsi_command(struct scsi_cmnd *srb,
  * pick up from where this one left off. */
 
 unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
-	unsigned int buflen, struct scsi_cmnd *srb, unsigned int *index,
+	unsigned int buflen, struct scsi_cmnd *srb, struct scatterlist **sgptr,
 	unsigned int *offset, enum xfer_buf_dir dir)
 {
 	unsigned int cnt;
@@ -184,16 +184,17 @@ unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
 	 * located in high memory -- then kmap() will map it to a temporary
 	 * position in the kernel's virtual address space. */
 	} else {
-		struct scatterlist *sg =
-				(struct scatterlist *) srb->request_buffer
-				+ *index;
+		struct scatterlist *sg = *sgptr;
+
+		if (!sg)
+			sg = (struct scatterlist *) srb->request_buffer;
 
 		/* This loop handles a single s-g list entry, which may
 		 * include multiple pages.  Find the initial page structure
 		 * and the starting offset within the page, and update
 		 * the *offset and *index values for the next loop. */
 		cnt = 0;
-		while (cnt < buflen && *index < srb->use_sg) {
+		while (cnt < buflen) {
 			struct page *page = sg->page +
 					((sg->offset + *offset) >> PAGE_SHIFT);
 			unsigned int poff =
@@ -209,8 +210,7 @@ unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
 
 				/* Transfer continues to next s-g entry */
 				*offset = 0;
-				++*index;
-				++sg;
+				sg = sg_next(sg);
 			}
 
 			/* Transfer the data for all the pages in this
@@ -234,6 +234,7 @@ unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
 				sglen -= plen;
 			}
 		}
+		*sgptr = sg;
 	}
 
 	/* Return the amount actually transferred */
@@ -245,9 +246,10 @@ unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
 void usb_stor_set_xfer_buf(unsigned char *buffer,
 	unsigned int buflen, struct scsi_cmnd *srb)
 {
-	unsigned int index = 0, offset = 0;
+	unsigned int offset = 0;
+	struct scatterlist *sg = NULL;
 
-	usb_stor_access_xfer_buf(buffer, buflen, srb, &index, &offset,
+	usb_stor_access_xfer_buf(buffer, buflen, srb, &sg, &offset,
 			TO_XFER_BUF);
 	if (buflen < srb->request_bufflen)
 		srb->resid = srb->request_bufflen - buflen;
diff --git a/drivers/usb/storage/protocol.h b/drivers/usb/storage/protocol.h
index 845bed4b8031..8737a36891ca 100644
--- a/drivers/usb/storage/protocol.h
+++ b/drivers/usb/storage/protocol.h
@@ -52,7 +52,7 @@ extern void usb_stor_transparent_scsi_command(struct scsi_cmnd*,
 enum xfer_buf_dir	{TO_XFER_BUF, FROM_XFER_BUF};
 
 extern unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
-	unsigned int buflen, struct scsi_cmnd *srb, unsigned int *index,
+	unsigned int buflen, struct scsi_cmnd *srb, struct scatterlist **,
 	unsigned int *offset, enum xfer_buf_dir dir);
 
 extern void usb_stor_set_xfer_buf(unsigned char *buffer,
diff --git a/drivers/usb/storage/sddr09.c b/drivers/usb/storage/sddr09.c
index b2ed2a3e6fca..b12202c5da2d 100644
--- a/drivers/usb/storage/sddr09.c
+++ b/drivers/usb/storage/sddr09.c
@@ -705,7 +705,8 @@ sddr09_read_data(struct us_data *us,
 	unsigned char *buffer;
 	unsigned int lba, maxlba, pba;
 	unsigned int page, pages;
-	unsigned int len, index, offset;
+	unsigned int len, offset;
+	struct scatterlist *sg;
 	int result;
 
 	// Figure out the initial LBA and page
@@ -730,7 +731,8 @@ sddr09_read_data(struct us_data *us,
 	// contiguous LBA's. Another exercise left to the student.
 
 	result = 0;
-	index = offset = 0;
+	offset = 0;
+	sg = NULL;
 
 	while (sectors > 0) {
 
@@ -777,7 +779,7 @@ sddr09_read_data(struct us_data *us,
 
 		// Store the data in the transfer buffer
 		usb_stor_access_xfer_buf(buffer, len, us->srb,
-				&index, &offset, TO_XFER_BUF);
+				&sg, &offset, TO_XFER_BUF);
 
 		page = 0;
 		lba++;
@@ -931,7 +933,8 @@ sddr09_write_data(struct us_data *us,
 	unsigned int pagelen, blocklen;
 	unsigned char *blockbuffer;
 	unsigned char *buffer;
-	unsigned int len, index, offset;
+	unsigned int len, offset;
+	struct scatterlist *sg;
 	int result;
 
 	// Figure out the initial LBA and page
@@ -968,7 +971,8 @@ sddr09_write_data(struct us_data *us,
 	}
 
 	result = 0;
-	index = offset = 0;
+	offset = 0;
+	sg = NULL;
 
 	while (sectors > 0) {
 
@@ -987,7 +991,7 @@ sddr09_write_data(struct us_data *us,
 
 		// Get the data from the transfer buffer
 		usb_stor_access_xfer_buf(buffer, len, us->srb,
-				&index, &offset, FROM_XFER_BUF);
+				&sg, &offset, FROM_XFER_BUF);
 
 		result = sddr09_write_lba(us, lba, page, pages,
 				buffer, blockbuffer);
diff --git a/drivers/usb/storage/sddr55.c b/drivers/usb/storage/sddr55.c
index 0b1b5b59ca7b..d43a3415e12f 100644
--- a/drivers/usb/storage/sddr55.c
+++ b/drivers/usb/storage/sddr55.c
@@ -167,7 +167,8 @@ static int sddr55_read_data(struct us_data *us,
 	unsigned long address;
 
 	unsigned short pages;
-	unsigned int len, index, offset;
+	unsigned int len, offset;
+	struct scatterlist *sg;
 
 	// Since we only read in one block at a time, we have to create
 	// a bounce buffer and move the data a piece at a time between the
@@ -178,7 +179,8 @@ static int sddr55_read_data(struct us_data *us,
 	buffer = kmalloc(len, GFP_NOIO);
 	if (buffer == NULL)
 		return USB_STOR_TRANSPORT_ERROR; /* out of memory */
-	index = offset = 0;
+	offset = 0;
+	sg = NULL;
 
 	while (sectors>0) {
 
@@ -255,7 +257,7 @@ static int sddr55_read_data(struct us_data *us,
 
 		// Store the data in the transfer buffer
 		usb_stor_access_xfer_buf(buffer, len, us->srb,
-				&index, &offset, TO_XFER_BUF);
+				&sg, &offset, TO_XFER_BUF);
 
 		page = 0;
 		lba++;
@@ -287,7 +289,8 @@ static int sddr55_write_data(struct us_data *us,
 
 	unsigned short pages;
 	int i;
-	unsigned int len, index, offset;
+	unsigned int len, offset;
+	struct scatterlist *sg;
 
 	/* check if we are allowed to write */
 	if (info->read_only || info->force_read_only) {
@@ -304,7 +307,8 @@ static int sddr55_write_data(struct us_data *us,
 	buffer = kmalloc(len, GFP_NOIO);
 	if (buffer == NULL)
 		return USB_STOR_TRANSPORT_ERROR;
-	index = offset = 0;
+	offset = 0;
+	sg = NULL;
 
 	while (sectors > 0) {
 
@@ -322,7 +326,7 @@ static int sddr55_write_data(struct us_data *us,
 
 		// Get the data from the transfer buffer
 		usb_stor_access_xfer_buf(buffer, len, us->srb,
-				&index, &offset, FROM_XFER_BUF);
+				&sg, &offset, FROM_XFER_BUF);
 
 		US_DEBUGP("Write %02X pages, to PBA %04X"
 			" (LBA %04X) page %02X\n",
diff --git a/drivers/usb/storage/shuttle_usbat.c b/drivers/usb/storage/shuttle_usbat.c
index 17ca4d73577b..cb22a9ad1694 100644
--- a/drivers/usb/storage/shuttle_usbat.c
+++ b/drivers/usb/storage/shuttle_usbat.c
@@ -993,7 +993,8 @@ static int usbat_flash_read_data(struct us_data *us,
 	unsigned char  thistime;
 	unsigned int totallen, alloclen;
 	int len, result;
-	unsigned int sg_idx = 0, sg_offset = 0;
+	unsigned int sg_offset = 0;
+	struct scatterlist *sg = NULL;
 
 	result = usbat_flash_check_media(us, info);
 	if (result != USB_STOR_TRANSPORT_GOOD)
@@ -1047,7 +1048,7 @@ static int usbat_flash_read_data(struct us_data *us,
 	
 		/* Store the data in the transfer buffer */
 		usb_stor_access_xfer_buf(buffer, len, us->srb,
-					 &sg_idx, &sg_offset, TO_XFER_BUF);
+					 &sg, &sg_offset, TO_XFER_BUF);
 
 		sector += thistime;
 		totallen -= len;
@@ -1083,7 +1084,8 @@ static int usbat_flash_write_data(struct us_data *us,
 	unsigned char  thistime;
 	unsigned int totallen, alloclen;
 	int len, result;
-	unsigned int sg_idx = 0, sg_offset = 0;
+	unsigned int sg_offset = 0;
+	struct scatterlist *sg = NULL;
 
 	result = usbat_flash_check_media(us, info);
 	if (result != USB_STOR_TRANSPORT_GOOD)
@@ -1122,7 +1124,7 @@ static int usbat_flash_write_data(struct us_data *us,
 
 		/* Get the data from the transfer buffer */
 		usb_stor_access_xfer_buf(buffer, len, us->srb,
-					 &sg_idx, &sg_offset, FROM_XFER_BUF);
+					 &sg, &sg_offset, FROM_XFER_BUF);
 
 		/* ATA command 0x30 (WRITE SECTORS) */
 		usbat_pack_ata_sector_cmd(command, thistime, sector, 0x30);
@@ -1162,8 +1164,8 @@ static int usbat_hp8200e_handle_read10(struct us_data *us,
 	unsigned char *buffer;
 	unsigned int len;
 	unsigned int sector;
-	unsigned int sg_segment = 0;
 	unsigned int sg_offset = 0;
+	struct scatterlist *sg = NULL;
 
 	US_DEBUGP("handle_read10: transfersize %d\n",
 		srb->transfersize);
@@ -1220,9 +1222,6 @@ static int usbat_hp8200e_handle_read10(struct us_data *us,
 	sector |= short_pack(data[7+5], data[7+4]);
 	transferred = 0;
 
-	sg_segment = 0; /* for keeping track of where we are in */
-	sg_offset = 0;  /* the scatter/gather list */
-
 	while (transferred != srb->request_bufflen) {
 
 		if (len > srb->request_bufflen - transferred)
@@ -1255,7 +1254,7 @@ static int usbat_hp8200e_handle_read10(struct us_data *us,
 
 		/* Store the data in the transfer buffer */
 		usb_stor_access_xfer_buf(buffer, len, srb,
-				 &sg_segment, &sg_offset, TO_XFER_BUF);
+				 &sg, &sg_offset, TO_XFER_BUF);
 
 		/* Update the amount transferred and the sector number */
 
diff --git a/fs/bio.c b/fs/bio.c
index 5f604f269dfa..d59ddbf79626 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -109,11 +109,14 @@ static inline struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned lon
 
 void bio_free(struct bio *bio, struct bio_set *bio_set)
 {
-	const int pool_idx = BIO_POOL_IDX(bio);
+	if (bio->bi_io_vec) {
+		const int pool_idx = BIO_POOL_IDX(bio);
 
-	BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS);
+		BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS);
+
+		mempool_free(bio->bi_io_vec, bio_set->bvec_pools[pool_idx]);
+	}
 
-	mempool_free(bio->bi_io_vec, bio_set->bvec_pools[pool_idx]);
 	mempool_free(bio, bio_set->bio_pool);
 }
 
@@ -127,21 +130,9 @@ static void bio_fs_destructor(struct bio *bio)
 
 void bio_init(struct bio *bio)
 {
-	bio->bi_next = NULL;
-	bio->bi_bdev = NULL;
+	memset(bio, 0, sizeof(*bio));
 	bio->bi_flags = 1 << BIO_UPTODATE;
-	bio->bi_rw = 0;
-	bio->bi_vcnt = 0;
-	bio->bi_idx = 0;
-	bio->bi_phys_segments = 0;
-	bio->bi_hw_segments = 0;
-	bio->bi_hw_front_size = 0;
-	bio->bi_hw_back_size = 0;
-	bio->bi_size = 0;
-	bio->bi_max_vecs = 0;
-	bio->bi_end_io = NULL;
 	atomic_set(&bio->bi_cnt, 1);
-	bio->bi_private = NULL;
 }
 
 /**
diff --git a/fs/splice.c b/fs/splice.c
index a7568bcc0f99..59a941d404d9 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1335,10 +1335,10 @@ static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 	if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len))
 		ret = -EFAULT;
 
+	buf->ops->unmap(pipe, buf, src);
 out:
 	if (ret > 0)
 		sd->u.userptr += ret;
-	buf->ops->unmap(pipe, buf, src);
 	return ret;
 }
 
diff --git a/include/asm-ia64/dma-mapping.h b/include/asm-ia64/dma-mapping.h
index 3ca6d5c14b2e..f1735a22d0ea 100644
--- a/include/asm-ia64/dma-mapping.h
+++ b/include/asm-ia64/dma-mapping.h
@@ -6,7 +6,7 @@
  *	David Mosberger-Tang <davidm@hpl.hp.com>
  */
 #include <asm/machvec.h>
-#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
 
 #define dma_alloc_coherent	platform_dma_alloc_coherent
 /* coherent mem. is cheap */
diff --git a/include/asm-ia64/scatterlist.h b/include/asm-ia64/scatterlist.h
index a452ea24205a..7d5234d50312 100644
--- a/include/asm-ia64/scatterlist.h
+++ b/include/asm-ia64/scatterlist.h
@@ -30,4 +30,6 @@ struct scatterlist {
 #define sg_dma_len(sg)		((sg)->dma_length)
 #define sg_dma_address(sg)	((sg)->dma_address)
 
+#define	ARCH_HAS_SG_CHAIN
+
 #endif /* _ASM_IA64_SCATTERLIST_H */
diff --git a/include/asm-powerpc/dma-mapping.h b/include/asm-powerpc/dma-mapping.h
index d05891608f74..2af321f36aba 100644
--- a/include/asm-powerpc/dma-mapping.h
+++ b/include/asm-powerpc/dma-mapping.h
@@ -6,149 +6,6 @@
  */
 #ifndef _ASM_DMA_MAPPING_H
 #define _ASM_DMA_MAPPING_H
-#ifdef __KERNEL__
-
-#include <linux/types.h>
-#include <linux/cache.h>
-/* need struct page definitions */
-#include <linux/mm.h>
-#include <asm/scatterlist.h>
-#include <asm/io.h>
-
-#define DMA_ERROR_CODE		(~(dma_addr_t)0x0)
-
-#ifdef CONFIG_NOT_COHERENT_CACHE
-/*
- * DMA-consistent mapping functions for PowerPCs that don't support
- * cache snooping.  These allocate/free a region of uncached mapped
- * memory space for use with DMA devices.  Alternatively, you could
- * allocate the space "normally" and use the cache management functions
- * to ensure it is consistent.
- */
-extern void *__dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp);
-extern void __dma_free_coherent(size_t size, void *vaddr);
-extern void __dma_sync(void *vaddr, size_t size, int direction);
-extern void __dma_sync_page(struct page *page, unsigned long offset,
-				 size_t size, int direction);
-
-#else /* ! CONFIG_NOT_COHERENT_CACHE */
-/*
- * Cache coherent cores.
- */
-
-#define __dma_alloc_coherent(gfp, size, handle)	NULL
-#define __dma_free_coherent(size, addr)		((void)0)
-#define __dma_sync(addr, size, rw)		((void)0)
-#define __dma_sync_page(pg, off, sz, rw)	((void)0)
-
-#endif /* ! CONFIG_NOT_COHERENT_CACHE */
-
-#ifdef CONFIG_PPC64
-/*
- * DMA operations are abstracted for G5 vs. i/pSeries, PCI vs. VIO
- */
-struct dma_mapping_ops {
-	void *		(*alloc_coherent)(struct device *dev, size_t size,
-				dma_addr_t *dma_handle, gfp_t flag);
-	void		(*free_coherent)(struct device *dev, size_t size,
-				void *vaddr, dma_addr_t dma_handle);
-	dma_addr_t	(*map_single)(struct device *dev, void *ptr,
-				size_t size, enum dma_data_direction direction);
-	void		(*unmap_single)(struct device *dev, dma_addr_t dma_addr,
-				size_t size, enum dma_data_direction direction);
-	int		(*map_sg)(struct device *dev, struct scatterlist *sg,
-				int nents, enum dma_data_direction direction);
-	void		(*unmap_sg)(struct device *dev, struct scatterlist *sg,
-				int nents, enum dma_data_direction direction);
-	int		(*dma_supported)(struct device *dev, u64 mask);
-	int		(*set_dma_mask)(struct device *dev, u64 dma_mask);
-};
-
-static inline struct dma_mapping_ops *get_dma_ops(struct device *dev)
-{
-	/* We don't handle the NULL dev case for ISA for now. We could
-	 * do it via an out of line call but it is not needed for now. The
-	 * only ISA DMA device we support is the floppy and we have a hack
-	 * in the floppy driver directly to get a device for us.
-	 */
-	if (unlikely(dev == NULL || dev->archdata.dma_ops == NULL))
-		return NULL;
-	return dev->archdata.dma_ops;
-}
-
-static inline int dma_supported(struct device *dev, u64 mask)
-{
-	struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-	if (unlikely(dma_ops == NULL))
-		return 0;
-	if (dma_ops->dma_supported == NULL)
-		return 1;
-	return dma_ops->dma_supported(dev, mask);
-}
-
-static inline int dma_set_mask(struct device *dev, u64 dma_mask)
-{
-	struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-	if (unlikely(dma_ops == NULL))
-		return -EIO;
-	if (dma_ops->set_dma_mask != NULL)
-		return dma_ops->set_dma_mask(dev, dma_mask);
-	if (!dev->dma_mask || !dma_supported(dev, dma_mask))
-		return -EIO;
-	*dev->dma_mask = dma_mask;
-	return 0;
-}
-
-static inline void *dma_alloc_coherent(struct device *dev, size_t size,
-				       dma_addr_t *dma_handle, gfp_t flag)
-{
-	struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-	BUG_ON(!dma_ops);
-	return dma_ops->alloc_coherent(dev, size, dma_handle, flag);
-}
-
-static inline void dma_free_coherent(struct device *dev, size_t size,
-				     void *cpu_addr, dma_addr_t dma_handle)
-{
-	struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-	BUG_ON(!dma_ops);
-	dma_ops->free_coherent(dev, size, cpu_addr, dma_handle);
-}
-
-static inline dma_addr_t dma_map_single(struct device *dev, void *cpu_addr,
-					size_t size,
-					enum dma_data_direction direction)
-{
-	struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-	BUG_ON(!dma_ops);
-	return dma_ops->map_single(dev, cpu_addr, size, direction);
-}
-
-static inline void dma_unmap_single(struct device *dev, dma_addr_t dma_addr,
-				    size_t size,
-				    enum dma_data_direction direction)
-{
-	struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-	BUG_ON(!dma_ops);
-	dma_ops->unmap_single(dev, dma_addr, size, direction);
-}
-
-static inline dma_addr_t dma_map_page(struct device *dev, struct page *page,
-				      unsigned long offset, size_t size,
-				      enum dma_data_direction direction)
-{
-	struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-	BUG_ON(!dma_ops);
-	return dma_ops->map_single(dev, page_address(page) + offset, size,
-			direction);
-}
 
 static inline void dma_unmap_page(struct device *dev, dma_addr_t dma_address,
 				  size_t size,
@@ -276,14 +133,15 @@ static inline void dma_unmap_page(struct device *dev, dma_addr_t dma_address,
 }
 
 static inline int
-dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
+dma_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
 	   enum dma_data_direction direction)
 {
+	struct scatterlist *sg;
 	int i;
 
 	BUG_ON(direction == DMA_NONE);
 
-	for (i = 0; i < nents; i++, sg++) {
+	for_each_sg(sgl, sg, nents, i) {
 		BUG_ON(!sg->page);
 		__dma_sync_page(sg->page, sg->offset, sg->length, direction);
 		sg->dma_address = page_to_bus(sg->page) + sg->offset;
@@ -318,26 +176,28 @@ static inline void dma_sync_single_for_device(struct device *dev,
 }
 
 static inline void dma_sync_sg_for_cpu(struct device *dev,
-		struct scatterlist *sg, int nents,
+		struct scatterlist *sgl, int nents,
 		enum dma_data_direction direction)
 {
+	struct scatterlist *sg;
 	int i;
 
 	BUG_ON(direction == DMA_NONE);
 
-	for (i = 0; i < nents; i++, sg++)
+	for_each_sg(sgl, sg, nents, i)
 		__dma_sync_page(sg->page, sg->offset, sg->length, direction);
 }
 
 static inline void dma_sync_sg_for_device(struct device *dev,
-		struct scatterlist *sg, int nents,
+		struct scatterlist *sgl, int nents,
 		enum dma_data_direction direction)
 {
+	struct scatterlist *sg;
 	int i;
 
 	BUG_ON(direction == DMA_NONE);
 
-	for (i = 0; i < nents; i++, sg++)
+	for_each_sg(sgl, sg, nents, i)
 		__dma_sync_page(sg->page, sg->offset, sg->length, direction);
 }
 
diff --git a/include/asm-powerpc/scatterlist.h b/include/asm-powerpc/scatterlist.h
index 8c992d1491d4..b075f619c3b7 100644
--- a/include/asm-powerpc/scatterlist.h
+++ b/include/asm-powerpc/scatterlist.h
@@ -41,5 +41,7 @@ struct scatterlist {
 #define ISA_DMA_THRESHOLD	(~0UL)
 #endif
 
+#define ARCH_HAS_SG_CHAIN
+
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_SCATTERLIST_H */
diff --git a/include/asm-sparc/scatterlist.h b/include/asm-sparc/scatterlist.h
index a4fcf9ac9649..4055af90ad7e 100644
--- a/include/asm-sparc/scatterlist.h
+++ b/include/asm-sparc/scatterlist.h
@@ -19,4 +19,6 @@ struct scatterlist {
 
 #define ISA_DMA_THRESHOLD (~0UL)
 
+#define ARCH_HAS_SG_CHAIN
+
 #endif /* !(_SPARC_SCATTERLIST_H) */
diff --git a/include/asm-sparc64/scatterlist.h b/include/asm-sparc64/scatterlist.h
index 048fdb40e81d..703c5bbe6c8c 100644
--- a/include/asm-sparc64/scatterlist.h
+++ b/include/asm-sparc64/scatterlist.h
@@ -20,4 +20,6 @@ struct scatterlist {
 
 #define ISA_DMA_THRESHOLD	(~0UL)
 
+#define ARCH_HAS_SG_CHAIN
+
 #endif /* !(_SPARC64_SCATTERLIST_H) */
diff --git a/include/asm-x86/dma-mapping_32.h b/include/asm-x86/dma-mapping_32.h
index f1d72d177f68..6a2d26cb5da6 100644
--- a/include/asm-x86/dma-mapping_32.h
+++ b/include/asm-x86/dma-mapping_32.h
@@ -2,10 +2,10 @@
 #define _ASM_I386_DMA_MAPPING_H
 
 #include <linux/mm.h>
+#include <linux/scatterlist.h>
 
 #include <asm/cache.h>
 #include <asm/io.h>
-#include <asm/scatterlist.h>
 #include <asm/bug.h>
 
 #define dma_alloc_noncoherent(d, s, h, f) dma_alloc_coherent(d, s, h, f)
@@ -35,18 +35,19 @@ dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
 }
 
 static inline int
-dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
+dma_map_sg(struct device *dev, struct scatterlist *sglist, int nents,
 	   enum dma_data_direction direction)
 {
+	struct scatterlist *sg;
 	int i;
 
 	BUG_ON(!valid_dma_direction(direction));
-	WARN_ON(nents == 0 || sg[0].length == 0);
+	WARN_ON(nents == 0 || sglist[0].length == 0);
 
-	for (i = 0; i < nents; i++ ) {
-		BUG_ON(!sg[i].page);
+	for_each_sg(sglist, sg, nents, i) {
+		BUG_ON(!sg->page);
 
-		sg[i].dma_address = page_to_phys(sg[i].page) + sg[i].offset;
+		sg->dma_address = page_to_phys(sg->page) + sg->offset;
 	}
 
 	flush_write_buffers();
diff --git a/include/asm-x86/dma-mapping_64.h b/include/asm-x86/dma-mapping_64.h
index 6897e2a436e5..ecd0f6125ba3 100644
--- a/include/asm-x86/dma-mapping_64.h
+++ b/include/asm-x86/dma-mapping_64.h
@@ -6,8 +6,7 @@
  * documentation.
  */
 
-
-#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
 #include <asm/io.h>
 #include <asm/swiotlb.h>
 
diff --git a/include/asm-x86/scatterlist_32.h b/include/asm-x86/scatterlist_32.h
index d7e45a8f1aae..bd5164aa8f63 100644
--- a/include/asm-x86/scatterlist_32.h
+++ b/include/asm-x86/scatterlist_32.h
@@ -10,6 +10,8 @@ struct scatterlist {
     unsigned int	length;
 };
 
+#define ARCH_HAS_SG_CHAIN
+
 /* These macros should be used after a pci_map_sg call has been done
  * to get bus addresses of each of the SG entries and their lengths.
  * You should only work with the number of sg entries pci_map_sg
diff --git a/include/asm-x86/scatterlist_64.h b/include/asm-x86/scatterlist_64.h
index eaf7ada27e14..ef3986ba4b79 100644
--- a/include/asm-x86/scatterlist_64.h
+++ b/include/asm-x86/scatterlist_64.h
@@ -11,6 +11,8 @@ struct scatterlist {
     unsigned int        dma_length;
 };
 
+#define ARCH_HAS_SG_CHAIN
+
 #define ISA_DMA_THRESHOLD (0x00ffffff)
 
 /* These macros should be used after a pci_map_sg call has been done
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 089a8bc55dd4..4da441337d6e 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -176,13 +176,28 @@ struct bio {
 #define bio_offset(bio)		bio_iovec((bio))->bv_offset
 #define bio_segments(bio)	((bio)->bi_vcnt - (bio)->bi_idx)
 #define bio_sectors(bio)	((bio)->bi_size >> 9)
-#define bio_cur_sectors(bio)	(bio_iovec(bio)->bv_len >> 9)
-#define bio_data(bio)		(page_address(bio_page((bio))) + bio_offset((bio)))
 #define bio_barrier(bio)	((bio)->bi_rw & (1 << BIO_RW_BARRIER))
 #define bio_sync(bio)		((bio)->bi_rw & (1 << BIO_RW_SYNC))
 #define bio_failfast(bio)	((bio)->bi_rw & (1 << BIO_RW_FAILFAST))
 #define bio_rw_ahead(bio)	((bio)->bi_rw & (1 << BIO_RW_AHEAD))
 #define bio_rw_meta(bio)	((bio)->bi_rw & (1 << BIO_RW_META))
+#define bio_empty_barrier(bio)	(bio_barrier(bio) && !(bio)->bi_size)
+
+static inline unsigned int bio_cur_sectors(struct bio *bio)
+{
+	if (bio->bi_vcnt)
+		return bio_iovec(bio)->bv_len >> 9;
+
+	return 0;
+}
+
+static inline void *bio_data(struct bio *bio)
+{
+	if (bio->bi_vcnt)
+		return page_address(bio_page(bio)) + bio_offset(bio);
+
+	return NULL;
+}
 
 /*
  * will die
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 5ed888b04b29..bbf906a0b419 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -330,7 +330,6 @@ typedef void (unplug_fn) (struct request_queue *);
 
 struct bio_vec;
 typedef int (merge_bvec_fn) (struct request_queue *, struct bio *, struct bio_vec *);
-typedef int (issue_flush_fn) (struct request_queue *, struct gendisk *, sector_t *);
 typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
 typedef void (softirq_done_fn)(struct request *);
 
@@ -368,7 +367,6 @@ struct request_queue
 	prep_rq_fn		*prep_rq_fn;
 	unplug_fn		*unplug_fn;
 	merge_bvec_fn		*merge_bvec_fn;
-	issue_flush_fn		*issue_flush_fn;
 	prepare_flush_fn	*prepare_flush_fn;
 	softirq_done_fn		*softirq_done_fn;
 
@@ -540,6 +538,7 @@ enum {
 #define blk_barrier_rq(rq)	((rq)->cmd_flags & REQ_HARDBARRIER)
 #define blk_fua_rq(rq)		((rq)->cmd_flags & REQ_FUA)
 #define blk_bidi_rq(rq)		((rq)->next_rq != NULL)
+#define blk_empty_barrier(rq)	(blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors)
 
 #define list_entry_rq(ptr)	list_entry((ptr), struct request, queuelist)
 
@@ -729,7 +728,9 @@ static inline void blk_run_address_space(struct address_space *mapping)
 extern int end_that_request_first(struct request *, int, int);
 extern int end_that_request_chunk(struct request *, int, int);
 extern void end_that_request_last(struct request *, int);
-extern void end_request(struct request *req, int uptodate);
+extern void end_request(struct request *, int);
+extern void end_queued_request(struct request *, int);
+extern void end_dequeued_request(struct request *, int);
 extern void blk_complete_request(struct request *);
 
 /*
@@ -767,7 +768,6 @@ extern void blk_queue_dma_alignment(struct request_queue *, int);
 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
-extern void blk_queue_issue_flush_fn(struct request_queue *, issue_flush_fn *);
 extern int blk_do_ordered(struct request_queue *, struct request **);
 extern unsigned blk_ordered_cur_seq(struct request_queue *);
 extern unsigned blk_ordered_req_seq(struct request *);
diff --git a/include/linux/i2o.h b/include/linux/i2o.h
index 9752307d16ba..7da5b98d90e6 100644
--- a/include/linux/i2o.h
+++ b/include/linux/i2o.h
@@ -32,6 +32,7 @@
 #include <linux/workqueue.h>	/* work_struct */
 #include <linux/mempool.h>
 #include <linux/mutex.h>
+#include <linux/scatterlist.h>
 
 #include <asm/io.h>
 #include <asm/semaphore.h>	/* Needed for MUTEX init macros */
@@ -837,7 +838,7 @@ static inline int i2o_dma_map_sg(struct i2o_controller *c,
 		if ((sizeof(dma_addr_t) > 4) && c->pae_support)
 			*mptr++ = cpu_to_le32(i2o_dma_high(sg_dma_address(sg)));
 #endif
-		sg++;
+		sg = sg_next(sg);
 	}
 	*sg_ptr = mptr;
 
diff --git a/include/linux/ide.h b/include/linux/ide.h
index 02a27e8cbad2..30a1931466a6 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -772,7 +772,7 @@ typedef struct hwif_s {
 
 	unsigned int nsect;
 	unsigned int nleft;
-	unsigned int cursg;
+	struct scatterlist *cursg;
 	unsigned int cursg_ofs;
 
 	int		rqsize;		/* max sectors per request */
@@ -1093,11 +1093,6 @@ extern ide_startstop_t ide_do_reset (ide_drive_t *);
 extern void ide_init_drive_cmd (struct request *rq);
 
 /*
- * this function returns error location sector offset in case of a write error
- */
-extern u64 ide_get_error_location(ide_drive_t *, char *);
-
-/*
  * "action" parameter type for ide_do_drive_cmd() below.
  */
 typedef enum {
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 229a9ff9f924..377e6d4d9be3 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -29,7 +29,7 @@
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/dma-mapping.h>
-#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
 #include <linux/io.h>
 #include <linux/ata.h>
 #include <linux/workqueue.h>
@@ -416,6 +416,7 @@ struct ata_queued_cmd {
 	unsigned long		flags;		/* ATA_QCFLAG_xxx */
 	unsigned int		tag;
 	unsigned int		n_elem;
+	unsigned int		n_iter;
 	unsigned int		orig_n_elem;
 
 	int			dma_dir;
@@ -426,7 +427,7 @@ struct ata_queued_cmd {
 	unsigned int		nbytes;
 	unsigned int		curbytes;
 
-	unsigned int		cursg;
+	struct scatterlist	*cursg;
 	unsigned int		cursg_ofs;
 
 	struct scatterlist	sgent;
@@ -1043,7 +1044,7 @@ ata_sg_is_last(struct scatterlist *sg, struct ata_queued_cmd *qc)
 		return 1;
 	if (qc->pad_len)
 		return 0;
-	if (((sg - qc->__sg) + 1) == qc->n_elem)
+	if (qc->n_iter == qc->n_elem)
 		return 1;
 	return 0;
 }
@@ -1051,6 +1052,7 @@ ata_sg_is_last(struct scatterlist *sg, struct ata_queued_cmd *qc)
 static inline struct scatterlist *
 ata_qc_first_sg(struct ata_queued_cmd *qc)
 {
+	qc->n_iter = 0;
 	if (qc->n_elem)
 		return qc->__sg;
 	if (qc->pad_len)
@@ -1063,8 +1065,8 @@ ata_qc_next_sg(struct scatterlist *sg, struct ata_queued_cmd *qc)
 {
 	if (sg == &qc->pad_sgent)
 		return NULL;
-	if (++sg - qc->__sg < qc->n_elem)
-		return sg;
+	if (++qc->n_iter < qc->n_elem)
+		return sg_next(sg);
 	if (qc->pad_len)
 		return &qc->pad_sgent;
 	return NULL;
@@ -1309,9 +1311,11 @@ static inline void ata_qc_reinit(struct ata_queued_cmd *qc)
 	qc->dma_dir = DMA_NONE;
 	qc->__sg = NULL;
 	qc->flags = 0;
-	qc->cursg = qc->cursg_ofs = 0;
+	qc->cursg = NULL;
+	qc->cursg_ofs = 0;
 	qc->nbytes = qc->curbytes = 0;
 	qc->n_elem = 0;
+	qc->n_iter = 0;
 	qc->err_mask = 0;
 	qc->pad_len = 0;
 	qc->sect_size = ATA_SECT_SIZE;
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 4efbd9c445f5..2dc7464cce52 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -20,4 +20,88 @@ static inline void sg_init_one(struct scatterlist *sg, const void *buf,
 	sg_set_buf(sg, buf, buflen);
 }
 
+/*
+ * We overload the LSB of the page pointer to indicate whether it's
+ * a valid sg entry, or whether it points to the start of a new scatterlist.
+ * Those low bits are there for everyone! (thanks mason :-)
+ */
+#define sg_is_chain(sg)		((unsigned long) (sg)->page & 0x01)
+#define sg_chain_ptr(sg)	\
+	((struct scatterlist *) ((unsigned long) (sg)->page & ~0x01))
+
+/**
+ * sg_next - return the next scatterlist entry in a list
+ * @sg:		The current sg entry
+ *
+ * Usually the next entry will be @sg@ + 1, but if this sg element is part
+ * of a chained scatterlist, it could jump to the start of a new
+ * scatterlist array.
+ *
+ * Note that the caller must ensure that there are further entries after
+ * the current entry, this function will NOT return NULL for an end-of-list.
+ *
+ */
+static inline struct scatterlist *sg_next(struct scatterlist *sg)
+{
+	sg++;
+
+	if (unlikely(sg_is_chain(sg)))
+		sg = sg_chain_ptr(sg);
+
+	return sg;
+}
+
+/*
+ * Loop over each sg element, following the pointer to a new list if necessary
+ */
+#define for_each_sg(sglist, sg, nr, __i)	\
+	for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg))
+
+/**
+ * sg_last - return the last scatterlist entry in a list
+ * @sgl:	First entry in the scatterlist
+ * @nents:	Number of entries in the scatterlist
+ *
+ * Should only be used casually, it (currently) scan the entire list
+ * to get the last entry.
+ *
+ * Note that the @sgl@ pointer passed in need not be the first one,
+ * the important bit is that @nents@ denotes the number of entries that
+ * exist from @sgl@.
+ *
+ */
+static inline struct scatterlist *sg_last(struct scatterlist *sgl,
+					  unsigned int nents)
+{
+#ifndef ARCH_HAS_SG_CHAIN
+	struct scatterlist *ret = &sgl[nents - 1];
+#else
+	struct scatterlist *sg, *ret = NULL;
+	int i;
+
+	for_each_sg(sgl, sg, nents, i)
+		ret = sg;
+
+#endif
+	return ret;
+}
+
+/**
+ * sg_chain - Chain two sglists together
+ * @prv:	First scatterlist
+ * @prv_nents:	Number of entries in prv
+ * @sgl:	Second scatterlist
+ *
+ * Links @prv@ and @sgl@ together, to form a longer scatterlist.
+ *
+ */
+static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
+			    struct scatterlist *sgl)
+{
+#ifndef ARCH_HAS_SG_CHAIN
+	BUG();
+#endif
+	prv[prv_nents - 1].page = (struct page *) ((unsigned long) sgl | 0x01);
+}
+
 #endif /* _LINUX_SCATTERLIST_H */
diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index 9f8f80ab0c8b..702fcfeb37f1 100644
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -11,13 +11,6 @@
 #include <linux/types.h>
 
 /*
- *	The maximum sg list length SCSI can cope with
- *	(currently must be a power of 2 between 32 and 256)
- */
-#define SCSI_MAX_PHYS_SEGMENTS	MAX_PHYS_SEGMENTS
-
-
-/*
  *	SCSI command lengths
  */
 
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 65ab5145a09b..3f47e522a1ec 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -5,6 +5,7 @@
 #include <linux/list.h>
 #include <linux/types.h>
 #include <linux/timer.h>
+#include <linux/scatterlist.h>
 
 struct request;
 struct scatterlist;
@@ -68,7 +69,7 @@ struct scsi_cmnd {
 
 	/* These elements define the operation we ultimately want to perform */
 	unsigned short use_sg;	/* Number of pieces of scatter-gather */
-	unsigned short sglist_len;	/* size of malloc'd scatter-gather list */
+	unsigned short __use_sg;
 
 	unsigned underflow;	/* Return error if less than
 				   this amount is transferred */
@@ -128,7 +129,7 @@ extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
 extern void scsi_kunmap_atomic_sg(void *virt);
 
 extern struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *, gfp_t);
-extern void scsi_free_sgtable(struct scatterlist *, int);
+extern void scsi_free_sgtable(struct scsi_cmnd *);
 
 extern int scsi_dma_map(struct scsi_cmnd *cmd);
 extern void scsi_dma_unmap(struct scsi_cmnd *cmd);
@@ -148,6 +149,6 @@ static inline int scsi_get_resid(struct scsi_cmnd *cmd)
 }
 
 #define scsi_for_each_sg(cmd, sg, nseg, __i)			\
-	for (__i = 0, sg = scsi_sglist(cmd); __i < (nseg); __i++, (sg)++)
+	for_each_sg(scsi_sglist(cmd), sg, nseg, __i)
 
 #endif /* _SCSI_SCSI_CMND_H */
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 7d210cd6c38d..0fd4746ee39d 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -39,6 +39,9 @@ struct blk_queue_tags;
 #define DISABLE_CLUSTERING 0
 #define ENABLE_CLUSTERING 1
 
+#define DISABLE_SG_CHAINING 0
+#define ENABLE_SG_CHAINING 1
+
 enum scsi_eh_timer_return {
 	EH_NOT_HANDLED,
 	EH_HANDLED,
@@ -443,6 +446,15 @@ struct scsi_host_template {
 	unsigned ordered_tag:1;
 
 	/*
+	 * true if the low-level driver can support sg chaining. this
+	 * will be removed eventually when all the drivers are
+	 * converted to support sg chaining.
+	 *
+	 * Status: OBSOLETE
+	 */
+	unsigned use_sg_chaining:1;
+
+	/*
 	 * Countdown for host blocking with no commands outstanding
 	 */
 	unsigned int max_host_blocked;
@@ -586,6 +598,7 @@ struct Scsi_Host {
 	unsigned unchecked_isa_dma:1;
 	unsigned use_clustering:1;
 	unsigned use_blk_tcq:1;
+	unsigned use_sg_chaining:1;
 
 	/*
 	 * Host has requested that no further requests come through for the
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 30c1400e749e..c419ecf334c3 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -677,16 +677,17 @@ swiotlb_sync_single_range_for_device(struct device *hwdev, dma_addr_t dev_addr,
  * same here.
  */
 int
-swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nelems,
+swiotlb_map_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
 	       int dir)
 {
+	struct scatterlist *sg;
 	void *addr;
 	dma_addr_t dev_addr;
 	int i;
 
 	BUG_ON(dir == DMA_NONE);
 
-	for (i = 0; i < nelems; i++, sg++) {
+	for_each_sg(sgl, sg, nelems, i) {
 		addr = SG_ENT_VIRT_ADDRESS(sg);
 		dev_addr = virt_to_bus(addr);
 		if (swiotlb_force || address_needs_mapping(hwdev, dev_addr)) {
@@ -696,7 +697,7 @@ swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nelems,
 				   to do proper error handling. */
 				swiotlb_full(hwdev, sg->length, dir, 0);
 				swiotlb_unmap_sg(hwdev, sg - i, i, dir);
-				sg[0].dma_length = 0;
+				sgl[0].dma_length = 0;
 				return 0;
 			}
 			sg->dma_address = virt_to_bus(map);
@@ -712,19 +713,21 @@ swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nelems,
  * concerning calls here are the same as for swiotlb_unmap_single() above.
  */
 void
-swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg, int nelems,
+swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
 		 int dir)
 {
+	struct scatterlist *sg;
 	int i;
 
 	BUG_ON(dir == DMA_NONE);
 
-	for (i = 0; i < nelems; i++, sg++)
+	for_each_sg(sgl, sg, nelems, i) {
 		if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
 			unmap_single(hwdev, bus_to_virt(sg->dma_address),
 				     sg->dma_length, dir);
 		else if (dir == DMA_FROM_DEVICE)
 			dma_mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length);
+	}
 }
 
 /*
@@ -735,19 +738,21 @@ swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg, int nelems,
  * and usage.
  */
 static void
-swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sg,
+swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
 		int nelems, int dir, int target)
 {
+	struct scatterlist *sg;
 	int i;
 
 	BUG_ON(dir == DMA_NONE);
 
-	for (i = 0; i < nelems; i++, sg++)
+	for_each_sg(sgl, sg, nelems, i) {
 		if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
 			sync_single(hwdev, bus_to_virt(sg->dma_address),
 				    sg->dma_length, dir, target);
 		else if (dir == DMA_FROM_DEVICE)
 			dma_mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length);
+	}
 }
 
 void
diff --git a/mm/bounce.c b/mm/bounce.c
index 3b549bf31f7d..b6d2d0f1019b 100644
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -265,6 +265,12 @@ void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
 	mempool_t *pool;
 
 	/*
+	 * Data-less bio, nothing to bounce
+	 */
+	if (bio_empty_barrier(*bio_orig))
+		return;
+
+	/*
 	 * for non-isa bounce case, just check if the bounce pfn is equal
 	 * to or bigger than the highest pfn in the system -- in that case,
 	 * don't waste time iterating over bio segments
author	Linus Torvalds <torvalds@woody.linux-foundation.org>	2007-10-16 21:09:16 +0400
committer	Linus Torvalds <torvalds@woody.linux-foundation.org>	2007-10-16 21:09:16 +0400
commit	92d15c2ccbb3e31a3fc71ad28fdb55e1319383c0 (patch)
tree	8d83c0dc3c6b935d8367e331872f242b742f0a8a
parent	f20bf6125605acbbc7eb8c9420d7221c91aa83eb (diff)
parent	644bd2f048972d75eb1979b1fdca257d528ce687 (diff)
download	linux-92d15c2ccbb3e31a3fc71ad28fdb55e1319383c0.tar.xz