kernel/linux.git/block/blk-core.c, branch linux-2.6.28.y

block: fix setting of max_segment_size and seg_boundary mask

2008-12-03T11:55:55+00:00

Fix setting of max_segment_size and seg_boundary mask for stacked md/dm devices. When stacking devices (LVM over MD over SCSI) some of the request queue parameters are not set up correctly in some cases by default, namely max_segment_size and and seg_boundary mask. If you create MD device over SCSI, these attributes are zeroed. Problem become when there is over this mapping next device-mapper mapping - queue attributes are set in DM this way: request_queue max_segment_size seg_boundary_mask SCSI 65536 0xffffffff MD RAID1 0 0 LVM 65536 -1 (64bit) Unfortunately bio_add_page (resp. bio_phys_segments) calculates number of physical segments according to these parameters. During the generic_make_request() is segment cout recalculated and can increase bio->bi_phys_segments count over the allowed limit. (After bio_clone() in stack operation.) Thi is specially problem in CCISS driver, where it produce OOPS here BUG_ON(creq->nr_phys_segments > MAXSGENTRIES); (MAXSEGENTRIES is 31 by default.) Sometimes even this command is enough to cause oops: dd iflag=direct if=/dev// of=/dev/null bs=128000 count=10 This command generates bios with 250 sectors, allocated in 32 4k-pages (last page uses only 1024 bytes). For LVM layer, it allocates bio with 31 segments (still OK for CCISS), unfortunatelly on lower layer it is recalculated to 32 segments and this violates CCISS restriction and triggers BUG_ON(). The patch tries to fix it by: * initializing attributes above in queue request constructor blk_queue_make_request() * make sure that blk_queue_stack_limits() inherits setting (DM uses its own function to set the limits because it blk_queue_stack_limits() was introduced later. It should probably switch to use generic stack limit function too.) * sets the default seg_boundary value in one place (blkdev.h) * use this mask as default in DM (instead of -1, which differs in 64bit) Bugs related to this: https://bugzilla.redhat.com/show_bug.cgi?id=471639 http://bugzilla.kernel.org/show_bug.cgi?id=8672 Signed-off-by: Milan Broz Reviewed-by: Alasdair G Kergon Cc: Neil Brown Cc: FUJITA Tomonori Cc: Tejun Heo Cc: Mike Miller Signed-off-by: Jens Axboe

block: internal dequeue shouldn't start timer

2008-12-03T11:41:26+00:00

blkdev_dequeue_request() and elv_dequeue_request() are equivalent and both start the timeout timer. Barrier code dequeues the original barrier request but doesn't passes the request itself to lower level driver, only broken down proxy requests; however, as the original barrier code goes through the same dequeue path and timeout timer is started on it. If barrier sequence takes long enough, this timer expires but the low level driver has no idea about this request and oops follows. Timeout timer shouldn't have been started on the original barrier request as it never goes through actual IO. This patch unexports elv_dequeue_request(), which has no external user anyway, and makes it operate on elevator proper w/o adding the timer and make blkdev_dequeue_request() call elv_dequeue_request() and add timer. Internal users which don't pass the request to driver - barrier code and end_that_request_last() - are converted to use elv_dequeue_request(). Signed-off-by: Tejun Heo Cc: Mike Anderson Signed-off-by: Jens Axboe

blk: move blk_delete_timer call in end_that_request_last

2008-11-06T07:41:56+00:00

Move the calling blk_delete_timer to later in end_that_request_last to address an issue where blkdev_dequeue_request may have add a timer for the request. Signed-off-by: Mike Anderson Acked-by: Tejun Heo Signed-off-by: Jens Axboe

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

2008-10-17T16:29:55+00:00

* 'for-linus' of git://git.kernel.dk/linux-2.6-block: block: remove __generic_unplug_device() from exports block: move q->unplug_work initialization blktrace: pass zfcp driver data blktrace: add support for driver data block: fix current kernel-doc warnings block: only call ->request_fn when the queue is not stopped block: simplify string handling in elv_iosched_store() block: fix kernel-doc for blk_alloc_devt() block: fix nr_phys_segments miscalculation bug block: add partition attribute for partition number block: add BIG FAT WARNING to CONFIG_DEBUG_BLOCK_EXT_DEVT softirq: Add support for triggering softirq work on softirqs.

block: remove __generic_unplug_device() from exports

2008-10-17T12:03:08+00:00

The only out-of-core user is IDE, and that should be using blk_start_queueing() instead. Signed-off-by: Jens Axboe

block: move q->unplug_work initialization

2008-10-17T06:46:57+00:00

modprobe loop; rmmod loop effectively creates a blk_queue and destroys it which results in q->unplug_work being canceled without it ever being initialized. Therefore, move the initialization of q->unplug_work from blk_queue_make_request() to blk_alloc_queue*(). Reported-by: Alexey Dobriyan Signed-off-by: Peter Zijlstra Signed-off-by: Jens Axboe

block: fix current kernel-doc warnings

2008-10-17T06:46:57+00:00

Fix block kernel-doc warnings: Warning(linux-2.6.27-git4//fs/block_dev.c:1272): No description found for parameter 'path' Warning(linux-2.6.27-git4//block/blk-core.c:1021): No description found for parameter 'cpu' Warning(linux-2.6.27-git4//block/blk-core.c:1021): No description found for parameter 'part' Warning(/var/linsrc/linux-2.6.27-git4//block/genhd.c:544): No description found for parameter 'partno' Signed-off-by: Randy Dunlap Signed-off-by: Jens Axboe

block: only call ->request_fn when the queue is not stopped

2008-10-17T06:46:57+00:00

Callers should use either blk_run_queue/__blk_run_queue, or blk_start_queueing() to invoke request handling instead of calling ->request_fn() directly as that does not take the queue stopped flag into account. Also add appropriate comments on the above functions to detail their usage. Signed-off-by: Jens Axboe

[SCSI] block: separate failfast into multiple bits.

2008-10-13T13:28:52+00:00

Multipath is best at handling transport errors. If it gets a device error then there is not much the multipath layer can do. It will just access the same device but from a different path. This patch breaks up failfast into device, transport and driver errors. The multipath layers (md and dm mutlipath) only ask the lower levels to fast fail transport errors. The user of failfast, read ahead, will ask to fast fail on all errors. Note that blk_noretry_request will return true if any failfast bit is set. This allows drivers that do not support the multipath failfast bits to continue to fail on any failfast error like before. Drivers like scsi that are able to fail fast specific errors can check for the specific fail fast type. In the next patch I will convert scsi. Signed-off-by: Mike Christie Cc: Jens Axboe Signed-off-by: James Bottomley

block: remove end_{queued|dequeued}_request()

2008-10-09T06:56:21+00:00

This patch removes end_queued_request() and end_dequeued_request(), which are no longer used. As a results, users of __end_request() became only end_request(). So the actual code in __end_request() is moved to end_request() and __end_request() is removed. Signed-off-by: Kiyoshi Ueda Signed-off-by: Jun'ichi Nomura Signed-off-by: Jens Axboe