Merge branch 'for-4.1/drivers' of git://git.kernel.dk/linux-block

Pull block driver updates from Jens Axboe:
 "This is the block driver pull request for 4.1.  As with the core bits,
  this is a relatively slow round.  This pull request contains:

   - Various fixes and cleanups for NVMe, from Alexey Khoroshilov, Chong
     Yuan, myself, Keith Busch, and Murali Iyer.

   - Documentation and code cleanups for nbd from Markus Pargmann.

   - Change of brd maintainer to me, from Ross Zwisler.  At least the
     email doesn't bounce anymore then.

   - Two xen-blkback fixes from Tao Chen"

* 'for-4.1/drivers' of git://git.kernel.dk/linux-block: (23 commits)
  NVMe: Meta data handling through submit io ioctl
  NVMe: Add translation for block limits
  NVMe: Remove check for null
  NVMe: Fix error handling of class_create("nvme")
  xen-blkback: define pr_fmt macro to avoid the duplication of DRV_PFX
  xen-blkback: enlarge the array size of blkback name
  nbd: Return error pointer directly
  nbd: Return error code directly
  nbd: Remove fixme that was already fixed
  nbd: Restructure debugging prints
  nbd: Fix device bytesize type
  nbd: Replace kthread_create with kthread_run
  nbd: Remove kernel internal header
  Documentation: nbd: Add list of module parameters
  Documentation: nbd: Reformat to allow more documentation
  NVMe: increase depth of admin queue
  nvme: Fix PRP list calculation for non-4k system page size
  NVMe: Fix blk-mq hot cpu notification
  NVMe: embedded iod mask cleanup
  NVMe: Freeze admin queue on device failure
  ...

8 files changed, 207 insertions, 236 deletions

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 1fc83427199c..81fde9ef7f8e 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2107,13 +2107,12 @@ static int drbd_create_mempools(void)
 	if (drbd_md_io_page_pool == NULL)
 		goto Enomem;
 
-	drbd_request_mempool = mempool_create(number,
-		mempool_alloc_slab, mempool_free_slab, drbd_request_cache);
+	drbd_request_mempool = mempool_create_slab_pool(number,
+		drbd_request_cache);
 	if (drbd_request_mempool == NULL)
 		goto Enomem;
 
-	drbd_ee_mempool = mempool_create(number,
-		mempool_alloc_slab, mempool_free_slab, drbd_ee_cache);
+	drbd_ee_mempool = mempool_create_slab_pool(number, drbd_ee_cache);
 	if (drbd_ee_mempool == NULL)
 		goto Enomem;
 
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 34f2f0ba409b..3907202fb9d9 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -52,9 +52,10 @@ static struct drbd_request *drbd_req_new(struct drbd_device *device,
 {
 	struct drbd_request *req;
 
-	req = mempool_alloc(drbd_request_mempool, GFP_NOIO | __GFP_ZERO);
+	req = mempool_alloc(drbd_request_mempool, GFP_NOIO);
 	if (!req)
 		return NULL;
+	memset(req, 0, sizeof(*req));
 
 	drbd_req_make_private_bio(req, bio_src);
 	req->rq_state    = bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0;
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index a98c41f72c63..39e5f7fae3ef 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -32,28 +32,36 @@
 #include <net/sock.h>
 #include <linux/net.h>
 #include <linux/kthread.h>
+#include <linux/types.h>
 
 #include <asm/uaccess.h>
 #include <asm/types.h>
 
 #include <linux/nbd.h>
 
-#define NBD_MAGIC 0x68797548
+struct nbd_device {
+	int flags;
+	int harderror;		/* Code of hard error			*/
+	struct socket * sock;	/* If == NULL, device is not ready, yet	*/
+	int magic;
+
+	spinlock_t queue_lock;
+	struct list_head queue_head;	/* Requests waiting result */
+	struct request *active_req;
+	wait_queue_head_t active_wq;
+	struct list_head waiting_queue;	/* Requests to be sent */
+	wait_queue_head_t waiting_wq;
+
+	struct mutex tx_lock;
+	struct gendisk *disk;
+	int blksize;
+	loff_t bytesize;
+	pid_t pid; /* pid of nbd-client, if attached */
+	int xmit_timeout;
+	int disconnect; /* a disconnect has been requested by user */
+};
 
-#ifdef NDEBUG
-#define dprintk(flags, fmt...)
-#else /* NDEBUG */
-#define dprintk(flags, fmt...) do { \
-	if (debugflags & (flags)) printk(KERN_DEBUG fmt); \
-} while (0)
-#define DBG_IOCTL       0x0004
-#define DBG_INIT        0x0010
-#define DBG_EXIT        0x0020
-#define DBG_BLKDEV      0x0100
-#define DBG_RX          0x0200
-#define DBG_TX          0x0400
-static unsigned int debugflags;
-#endif /* NDEBUG */
+#define NBD_MAGIC 0x68797548
 
 static unsigned int nbds_max = 16;
 static struct nbd_device *nbd_dev;
@@ -71,25 +79,9 @@ static int max_part;
  */
 static DEFINE_SPINLOCK(nbd_lock);
 
-#ifndef NDEBUG
-static const char *ioctl_cmd_to_ascii(int cmd)
+static inline struct device *nbd_to_dev(struct nbd_device *nbd)
 {
-	switch (cmd) {
-	case NBD_SET_SOCK: return "set-sock";
-	case NBD_SET_BLKSIZE: return "set-blksize";
-	case NBD_SET_SIZE: return "set-size";
-	case NBD_SET_TIMEOUT: return "set-timeout";
-	case NBD_SET_FLAGS: return "set-flags";
-	case NBD_DO_IT: return "do-it";
-	case NBD_CLEAR_SOCK: return "clear-sock";
-	case NBD_CLEAR_QUE: return "clear-que";
-	case NBD_PRINT_DEBUG: return "print-debug";
-	case NBD_SET_SIZE_BLOCKS: return "set-size-blocks";
-	case NBD_DISCONNECT: return "disconnect";
-	case BLKROSET: return "set-read-only";
-	case BLKFLSBUF: return "flush-buffer-cache";
-	}
-	return "unknown";
+	return disk_to_dev(nbd->disk);
 }
 
 static const char *nbdcmd_to_ascii(int cmd)
@@ -103,30 +95,26 @@ static const char *nbdcmd_to_ascii(int cmd)
 	}
 	return "invalid";
 }
-#endif /* NDEBUG */
 
-static void nbd_end_request(struct request *req)
+static void nbd_end_request(struct nbd_device *nbd, struct request *req)
 {
 	int error = req->errors ? -EIO : 0;
 	struct request_queue *q = req->q;
 	unsigned long flags;
 
-	dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name,
-			req, error ? "failed" : "done");
+	dev_dbg(nbd_to_dev(nbd), "request %p: %s\n", req,
+		error ? "failed" : "done");
 
 	spin_lock_irqsave(q->queue_lock, flags);
 	__blk_end_request_all(req, error);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
+/*
+ * Forcibly shutdown the socket causing all listeners to error
+ */
 static void sock_shutdown(struct nbd_device *nbd, int lock)
 {
-	/* Forcibly shutdown the socket causing all listeners
-	 * to error
-	 *
-	 * FIXME: This code is duplicated from sys_shutdown, but
-	 * there should be a more generic interface rather than
-	 * calling socket ops directly here */
 	if (lock)
 		mutex_lock(&nbd->tx_lock);
 	if (nbd->sock) {
@@ -253,17 +241,15 @@ static int nbd_send_req(struct nbd_device *nbd, struct request *req)
 	}
 	memcpy(request.handle, &req, sizeof(req));
 
-	dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%uB)\n",
-			nbd->disk->disk_name, req,
-			nbdcmd_to_ascii(nbd_cmd(req)),
-			(unsigned long long)blk_rq_pos(req) << 9,
-			blk_rq_bytes(req));
+	dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
+		req, nbdcmd_to_ascii(nbd_cmd(req)),
+		(unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
 	result = sock_xmit(nbd, 1, &request, sizeof(request),
 			(nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0);
 	if (result <= 0) {
 		dev_err(disk_to_dev(nbd->disk),
 			"Send control failed (result %d)\n", result);
-		goto error_out;
+		return -EIO;
 	}
 
 	if (nbd_cmd(req) == NBD_CMD_WRITE) {
@@ -277,21 +263,18 @@ static int nbd_send_req(struct nbd_device *nbd, struct request *req)
 			flags = 0;
 			if (!rq_iter_last(bvec, iter))
 				flags = MSG_MORE;
-			dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
-					nbd->disk->disk_name, req, bvec.bv_len);
+			dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
+				req, bvec.bv_len);
 			result = sock_send_bvec(nbd, &bvec, flags);
 			if (result <= 0) {
 				dev_err(disk_to_dev(nbd->disk),
 					"Send data failed (result %d)\n",
 					result);
-				goto error_out;
+				return -EIO;
 			}
 		}
 	}
 	return 0;
-
-error_out:
-	return -EIO;
 }
 
 static struct request *nbd_find_request(struct nbd_device *nbd,
@@ -302,7 +285,7 @@ static struct request *nbd_find_request(struct nbd_device *nbd,
 
 	err = wait_event_interruptible(nbd->active_wq, nbd->active_req != xreq);
 	if (unlikely(err))
-		goto out;
+		return ERR_PTR(err);
 
 	spin_lock(&nbd->queue_lock);
 	list_for_each_entry_safe(req, tmp, &nbd->queue_head, queuelist) {
@@ -314,10 +297,7 @@ static struct request *nbd_find_request(struct nbd_device *nbd,
 	}
 	spin_unlock(&nbd->queue_lock);
 
-	err = -ENOENT;
-
-out:
-	return ERR_PTR(err);
+	return ERR_PTR(-ENOENT);
 }
 
 static inline int sock_recv_bvec(struct nbd_device *nbd, struct bio_vec *bvec)
@@ -371,8 +351,7 @@ static struct request *nbd_read_stat(struct nbd_device *nbd)
 		return req;
 	}
 
-	dprintk(DBG_RX, "%s: request %p: got reply\n",
-			nbd->disk->disk_name, req);
+	dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req);
 	if (nbd_cmd(req) == NBD_CMD_READ) {
 		struct req_iterator iter;
 		struct bio_vec bvec;
@@ -385,8 +364,8 @@ static struct request *nbd_read_stat(struct nbd_device *nbd)
 				req->errors++;
 				return req;
 			}
-			dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
-				nbd->disk->disk_name, req, bvec.bv_len);
+			dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
+				req, bvec.bv_len);
 		}
 	}
 	return req;
@@ -426,7 +405,7 @@ static int nbd_do_it(struct nbd_device *nbd)
 	}
 
 	while ((req = nbd_read_stat(nbd)) != NULL)
-		nbd_end_request(req);
+		nbd_end_request(nbd, req);
 
 	device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
 	nbd->pid = 0;
@@ -455,7 +434,7 @@ static void nbd_clear_que(struct nbd_device *nbd)
 				 queuelist);
 		list_del_init(&req->queuelist);
 		req->errors++;
-		nbd_end_request(req);
+		nbd_end_request(nbd, req);
 	}
 
 	while (!list_empty(&nbd->waiting_queue)) {
@@ -463,7 +442,7 @@ static void nbd_clear_que(struct nbd_device *nbd)
 				 queuelist);
 		list_del_init(&req->queuelist);
 		req->errors++;
-		nbd_end_request(req);
+		nbd_end_request(nbd, req);
 	}
 }
 
@@ -507,7 +486,7 @@ static void nbd_handle_req(struct nbd_device *nbd, struct request *req)
 	if (nbd_send_req(nbd, req) != 0) {
 		dev_err(disk_to_dev(nbd->disk), "Request send failed\n");
 		req->errors++;
-		nbd_end_request(req);
+		nbd_end_request(nbd, req);
 	} else {
 		spin_lock(&nbd->queue_lock);
 		list_add_tail(&req->queuelist, &nbd->queue_head);
@@ -522,7 +501,7 @@ static void nbd_handle_req(struct nbd_device *nbd, struct request *req)
 
 error_out:
 	req->errors++;
-	nbd_end_request(req);
+	nbd_end_request(nbd, req);
 }
 
 static int nbd_thread(void *data)
@@ -570,18 +549,18 @@ static void do_nbd_request(struct request_queue *q)
 
 		spin_unlock_irq(q->queue_lock);
 
-		dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n",
-				req->rq_disk->disk_name, req, req->cmd_type);
-
 		nbd = req->rq_disk->private_data;
 
 		BUG_ON(nbd->magic != NBD_MAGIC);
 
+		dev_dbg(nbd_to_dev(nbd), "request %p: dequeued (flags=%x)\n",
+			req, req->cmd_type);
+
 		if (unlikely(!nbd->sock)) {
 			dev_err(disk_to_dev(nbd->disk),
 				"Attempted send on closed socket\n");
 			req->errors++;
-			nbd_end_request(req);
+			nbd_end_request(nbd, req);
 			spin_lock_irq(q->queue_lock);
 			continue;
 		}
@@ -706,13 +685,13 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
 		else
 			blk_queue_flush(nbd->disk->queue, 0);
 
-		thread = kthread_create(nbd_thread, nbd, "%s",
-					nbd->disk->disk_name);
+		thread = kthread_run(nbd_thread, nbd, "%s",
+				     nbd->disk->disk_name);
 		if (IS_ERR(thread)) {
 			mutex_lock(&nbd->tx_lock);
 			return PTR_ERR(thread);
 		}
-		wake_up_process(thread);
+
 		error = nbd_do_it(nbd);
 		kthread_stop(thread);
 
@@ -768,10 +747,6 @@ static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
 
 	BUG_ON(nbd->magic != NBD_MAGIC);
 
-	/* Anyone capable of this syscall can do *real bad* things */
-	dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n",
-		nbd->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg);
-
 	mutex_lock(&nbd->tx_lock);
 	error = __nbd_ioctl(bdev, nbd, cmd, arg);
 	mutex_unlock(&nbd->tx_lock);
@@ -861,7 +836,6 @@ static int __init nbd_init(void)
 	}
 
 	printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR);
-	dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags);
 
 	for (i = 0; i < nbds_max; i++) {
 		struct gendisk *disk = nbd_dev[i].disk;
@@ -920,7 +894,3 @@ module_param(nbds_max, int, 0444);
 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
 module_param(max_part, int, 0444);
 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)");
-#ifndef NDEBUG
-module_param(debugflags, int, 0644);
-MODULE_PARM_DESC(debugflags, "flags for controlling debug output");
-#endif
diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index e23be20a3417..85b8036deaa3 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -44,7 +44,7 @@
 
 #define NVME_MINORS		(1U << MINORBITS)
 #define NVME_Q_DEPTH		1024
-#define NVME_AQ_DEPTH		64
+#define NVME_AQ_DEPTH		256
 #define SQ_SIZE(depth)		(depth * sizeof(struct nvme_command))
 #define CQ_SIZE(depth)		(depth * sizeof(struct nvme_completion))
 #define ADMIN_TIMEOUT		(admin_timeout * HZ)
@@ -152,6 +152,7 @@ struct nvme_cmd_info {
  */
 #define NVME_INT_PAGES		2
 #define NVME_INT_BYTES(dev)	(NVME_INT_PAGES * (dev)->page_size)
+#define NVME_INT_MASK		0x01
 
 /*
  * Will slightly overestimate the number of pages needed.  This is OK
@@ -257,7 +258,7 @@ static void *iod_get_private(struct nvme_iod *iod)
  */
 static bool iod_should_kfree(struct nvme_iod *iod)
 {
-	return (iod->private & 0x01) == 0;
+	return (iod->private & NVME_INT_MASK) == 0;
 }
 
 /* Special values must be less than 0x1000 */
@@ -301,8 +302,6 @@ static void *cancel_cmd_info(struct nvme_cmd_info *cmd, nvme_completion_fn *fn)
 static void async_req_completion(struct nvme_queue *nvmeq, void *ctx,
 						struct nvme_completion *cqe)
 {
-	struct request *req = ctx;
-
 	u32 result = le32_to_cpup(&cqe->result);
 	u16 status = le16_to_cpup(&cqe->status) >> 1;
 
@@ -311,8 +310,6 @@ static void async_req_completion(struct nvme_queue *nvmeq, void *ctx,
 	if (status == NVME_SC_SUCCESS)
 		dev_warn(nvmeq->q_dmadev,
 			"async event result %08x\n", result);
-
-	blk_mq_free_hctx_request(nvmeq->hctx, req);
 }
 
 static void abort_completion(struct nvme_queue *nvmeq, void *ctx,
@@ -432,7 +429,6 @@ static struct nvme_iod *nvme_alloc_iod(struct request *rq, struct nvme_dev *dev,
 {
 	unsigned size = !(rq->cmd_flags & REQ_DISCARD) ? blk_rq_bytes(rq) :
                                                 sizeof(struct nvme_dsm_range);
-	unsigned long mask = 0;
 	struct nvme_iod *iod;
 
 	if (rq->nr_phys_segments <= NVME_INT_PAGES &&
@@ -440,9 +436,8 @@ static struct nvme_iod *nvme_alloc_iod(struct request *rq, struct nvme_dev *dev,
 		struct nvme_cmd_info *cmd = blk_mq_rq_to_pdu(rq);
 
 		iod = cmd->iod;
-		mask = 0x01;
 		iod_init(iod, size, rq->nr_phys_segments,
-				(unsigned long) rq | 0x01);
+				(unsigned long) rq | NVME_INT_MASK);
 		return iod;
 	}
 
@@ -522,8 +517,6 @@ static void nvme_dif_remap(struct request *req,
 		return;
 
 	pmap = kmap_atomic(bip->bip_vec->bv_page) + bip->bip_vec->bv_offset;
-	if (!pmap)
-		return;
 
 	p = pmap;
 	virt = bip_get_seed(bip);
@@ -645,12 +638,12 @@ int nvme_setup_prps(struct nvme_dev *dev, struct nvme_iod *iod, int total_len,
 	struct scatterlist *sg = iod->sg;
 	int dma_len = sg_dma_len(sg);
 	u64 dma_addr = sg_dma_address(sg);
-	int offset = offset_in_page(dma_addr);
+	u32 page_size = dev->page_size;
+	int offset = dma_addr & (page_size - 1);
 	__le64 *prp_list;
 	__le64 **list = iod_list(iod);
 	dma_addr_t prp_dma;
 	int nprps, i;
-	u32 page_size = dev->page_size;
 
 	length -= (page_size - offset);
 	if (length <= 0)
@@ -1028,18 +1021,19 @@ static int nvme_submit_async_admin_req(struct nvme_dev *dev)
 	struct nvme_cmd_info *cmd_info;
 	struct request *req;
 
-	req = blk_mq_alloc_request(dev->admin_q, WRITE, GFP_ATOMIC, false);
+	req = blk_mq_alloc_request(dev->admin_q, WRITE, GFP_ATOMIC, true);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 
 	req->cmd_flags |= REQ_NO_TIMEOUT;
 	cmd_info = blk_mq_rq_to_pdu(req);
-	nvme_set_info(cmd_info, req, async_req_completion);
+	nvme_set_info(cmd_info, NULL, async_req_completion);
 
 	memset(&c, 0, sizeof(c));
 	c.common.opcode = nvme_admin_async_event;
 	c.common.command_id = req->tag;
 
+	blk_mq_free_hctx_request(nvmeq->hctx, req);
 	return __nvme_submit_cmd(nvmeq, &c);
 }
 
@@ -1347,6 +1341,9 @@ static int nvme_suspend_queue(struct nvme_queue *nvmeq)
 	nvmeq->cq_vector = -1;
 	spin_unlock_irq(&nvmeq->q_lock);
 
+	if (!nvmeq->qid && nvmeq->dev->admin_q)
+		blk_mq_freeze_queue_start(nvmeq->dev->admin_q);
+
 	irq_set_affinity_hint(vector, NULL);
 	free_irq(vector, nvmeq);
 
@@ -1378,8 +1375,6 @@ static void nvme_disable_queue(struct nvme_dev *dev, int qid)
 		adapter_delete_sq(dev, qid);
 		adapter_delete_cq(dev, qid);
 	}
-	if (!qid && dev->admin_q)
-		blk_mq_freeze_queue_start(dev->admin_q);
 
 	spin_lock_irq(&nvmeq->q_lock);
 	nvme_process_cq(nvmeq);
@@ -1583,6 +1578,7 @@ static int nvme_alloc_admin_tags(struct nvme_dev *dev)
 		dev->admin_tagset.ops = &nvme_mq_admin_ops;
 		dev->admin_tagset.nr_hw_queues = 1;
 		dev->admin_tagset.queue_depth = NVME_AQ_DEPTH - 1;
+		dev->admin_tagset.reserved_tags = 1;
 		dev->admin_tagset.timeout = ADMIN_TIMEOUT;
 		dev->admin_tagset.numa_node = dev_to_node(&dev->pci_dev->dev);
 		dev->admin_tagset.cmd_size = nvme_cmd_size(dev);
@@ -1749,25 +1745,31 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
 	struct nvme_dev *dev = ns->dev;
 	struct nvme_user_io io;
 	struct nvme_command c;
-	unsigned length, meta_len;
-	int status, i;
-	struct nvme_iod *iod, *meta_iod = NULL;
-	dma_addr_t meta_dma_addr;
-	void *meta, *uninitialized_var(meta_mem);
+	unsigned length, meta_len, prp_len;
+	int status, write;
+	struct nvme_iod *iod;
+	dma_addr_t meta_dma = 0;
+	void *meta = NULL;
 
 	if (copy_from_user(&io, uio, sizeof(io)))
 		return -EFAULT;
 	length = (io.nblocks + 1) << ns->lba_shift;
 	meta_len = (io.nblocks + 1) * ns->ms;
 
-	if (meta_len && ((io.metadata & 3) || !io.metadata))
+	if (meta_len && ((io.metadata & 3) || !io.metadata) && !ns->ext)
 		return -EINVAL;
+	else if (meta_len && ns->ext) {
+		length += meta_len;
+		meta_len = 0;
+	}
+
+	write = io.opcode & 1;
 
 	switch (io.opcode) {
 	case nvme_cmd_write:
 	case nvme_cmd_read:
 	case nvme_cmd_compare:
-		iod = nvme_map_user_pages(dev, io.opcode & 1, io.addr, length);
+		iod = nvme_map_user_pages(dev, write, io.addr, length);
 		break;
 	default:
 		return -EINVAL;
@@ -1776,6 +1778,27 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
 	if (IS_ERR(iod))
 		return PTR_ERR(iod);
 
+	prp_len = nvme_setup_prps(dev, iod, length, GFP_KERNEL);
+	if (length != prp_len) {
+		status = -ENOMEM;
+		goto unmap;
+	}
+	if (meta_len) {
+		meta = dma_alloc_coherent(&dev->pci_dev->dev, meta_len,
+						&meta_dma, GFP_KERNEL);
+		if (!meta) {
+			status = -ENOMEM;
+			goto unmap;
+		}
+		if (write) {
+			if (copy_from_user(meta, (void __user *)io.metadata,
+								meta_len)) {
+				status = -EFAULT;
+				goto unmap;
+			}
+		}
+	}
+
 	memset(&c, 0, sizeof(c));
 	c.rw.opcode = io.opcode;
 	c.rw.flags = io.flags;
@@ -1787,75 +1810,21 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
 	c.rw.reftag = cpu_to_le32(io.reftag);
 	c.rw.apptag = cpu_to_le16(io.apptag);
 	c.rw.appmask = cpu_to_le16(io.appmask);
-
-	if (meta_len) {
-		meta_iod = nvme_map_user_pages(dev, io.opcode & 1, io.metadata,
-								meta_len);
-		if (IS_ERR(meta_iod)) {
-			status = PTR_ERR(meta_iod);
-			meta_iod = NULL;
-			goto unmap;
-		}
-
-		meta_mem = dma_alloc_coherent(&dev->pci_dev->dev, meta_len,
-						&meta_dma_addr, GFP_KERNEL);
-		if (!meta_mem) {
-			status = -ENOMEM;
-			goto unmap;
-		}
-
-		if (io.opcode & 1) {
-			int meta_offset = 0;
-
-			for (i = 0; i < meta_iod->nents; i++) {
-				meta = kmap_atomic(sg_page(&meta_iod->sg[i])) +
-						meta_iod->sg[i].offset;
-				memcpy(meta_mem + meta_offset, meta,
-						meta_iod->sg[i].length);
-				kunmap_atomic(meta);
-				meta_offset += meta_iod->sg[i].length;
-			}
-		}
-
-		c.rw.metadata = cpu_to_le64(meta_dma_addr);
-	}
-
-	length = nvme_setup_prps(dev, iod, length, GFP_KERNEL);
 	c.rw.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
 	c.rw.prp2 = cpu_to_le64(iod->first_dma);
-
-	if (length != (io.nblocks + 1) << ns->lba_shift)
-		status = -ENOMEM;
-	else
-		status = nvme_submit_io_cmd(dev, ns, &c, NULL);
-
-	if (meta_len) {
-		if (status == NVME_SC_SUCCESS && !(io.opcode & 1)) {
-			int meta_offset = 0;
-
-			for (i = 0; i < meta_iod->nents; i++) {
-				meta = kmap_atomic(sg_page(&meta_iod->sg[i])) +
-						meta_iod->sg[i].offset;
-				memcpy(meta, meta_mem + meta_offset,
-						meta_iod->sg[i].length);
-				kunmap_atomic(meta);
-				meta_offset += meta_iod->sg[i].length;
-			}
-		}
-
-		dma_free_coherent(&dev->pci_dev->dev, meta_len, meta_mem,
-								meta_dma_addr);
-	}
-
+	c.rw.metadata = cpu_to_le64(meta_dma);
+	status = nvme_submit_io_cmd(dev, ns, &c, NULL);
  unmap:
-	nvme_unmap_user_pages(dev, io.opcode & 1, iod);
+	nvme_unmap_user_pages(dev, write, iod);
 	nvme_free_iod(dev, iod);
-
-	if (meta_iod) {
-		nvme_unmap_user_pages(dev, io.opcode & 1, meta_iod);
-		nvme_free_iod(dev, meta_iod);
+	if (meta) {
+		if (status == NVME_SC_SUCCESS && !write) {
+			if (copy_to_user((void __user *)io.metadata, meta,
+								meta_len))
+				status = -EFAULT;
+		}
+		dma_free_coherent(&dev->pci_dev->dev, meta_len, meta, meta_dma);
 	}
-
 	return status;
 }
 
@@ -2018,7 +1987,8 @@ static int nvme_revalidate_disk(struct gendisk *disk)
 	struct nvme_dev *dev = ns->dev;
 	struct nvme_id_ns *id;
 	dma_addr_t dma_addr;
-	int lbaf, pi_type, old_ms;
+	u8 lbaf, pi_type;
+	u16 old_ms;
 	unsigned short bs;
 
 	id = dma_alloc_coherent(&dev->pci_dev->dev, 4096, &dma_addr,
@@ -2039,6 +2009,7 @@ static int nvme_revalidate_disk(struct gendisk *disk)
 	lbaf = id->flbas & NVME_NS_FLBAS_LBA_MASK;
 	ns->lba_shift = id->lbaf[lbaf].ds;
 	ns->ms = le16_to_cpu(id->lbaf[lbaf].ms);
+	ns->ext = ns->ms && (id->flbas & NVME_NS_FLBAS_META_EXT);
 
 	/*
 	 * If identify namespace failed, use default 512 byte block size so
@@ -2055,14 +2026,14 @@ static int nvme_revalidate_disk(struct gendisk *disk)
 	if (blk_get_integrity(disk) && (ns->pi_type != pi_type ||
 				ns->ms != old_ms ||
 				bs != queue_logical_block_size(disk->queue) ||
-				(ns->ms && id->flbas & NVME_NS_FLBAS_META_EXT)))
+				(ns->ms && ns->ext)))
 		blk_integrity_unregister(disk);
 
 	ns->pi_type = pi_type;
 	blk_queue_logical_block_size(ns->queue, bs);
 
 	if (ns->ms && !blk_get_integrity(disk) && (disk->flags & GENHD_FL_UP) &&
-				!(id->flbas & NVME_NS_FLBAS_META_EXT))
+								!ns->ext)
 		nvme_init_integrity(ns);
 
 	if (id->ncap == 0 || (ns->ms && !blk_get_integrity(disk)))
@@ -2334,7 +2305,6 @@ static int nvme_dev_add(struct nvme_dev *dev)
 	dev->oncs = le16_to_cpup(&ctrl->oncs);
 	dev->abort_limit = ctrl->acl + 1;
 	dev->vwc = ctrl->vwc;
-	dev->event_limit = min(ctrl->aerl + 1, 8);
 	memcpy(dev->serial, ctrl->sn, sizeof(ctrl->sn));
 	memcpy(dev->model, ctrl->mn, sizeof(ctrl->mn));
 	memcpy(dev->firmware_rev, ctrl->fr, sizeof(ctrl->fr));
@@ -2881,6 +2851,7 @@ static int nvme_dev_start(struct nvme_dev *dev)
 
 	nvme_set_irq_hints(dev);
 
+	dev->event_limit = 1;
 	return result;
 
  free_tags:
@@ -3166,8 +3137,10 @@ static int __init nvme_init(void)
 		nvme_char_major = result;
 
 	nvme_class = class_create(THIS_MODULE, "nvme");
-	if (!nvme_class)
+	if (IS_ERR(nvme_class)) {
+		result = PTR_ERR(nvme_class);
 		goto unregister_chrdev;
+	}
 
 	result = pci_register_driver(&nvme_driver);
 	if (result)
diff --git a/drivers/block/nvme-scsi.c b/drivers/block/nvme-scsi.c
index e10196e0182d..6b736b00f63e 100644
--- a/drivers/block/nvme-scsi.c
+++ b/drivers/block/nvme-scsi.c
@@ -55,6 +55,7 @@ static int sg_version_num = 30534;	/* 2 digits for each component */
 #define VPD_SERIAL_NUMBER				0x80
 #define VPD_DEVICE_IDENTIFIERS				0x83
 #define VPD_EXTENDED_INQUIRY				0x86
+#define VPD_BLOCK_LIMITS				0xB0
 #define VPD_BLOCK_DEV_CHARACTERISTICS			0xB1
 
 /* CDB offsets */
@@ -132,9 +133,10 @@ static int sg_version_num = 30534;	/* 2 digits for each component */
 #define INQ_UNIT_SERIAL_NUMBER_PAGE			0x80
 #define INQ_DEVICE_IDENTIFICATION_PAGE			0x83
 #define INQ_EXTENDED_INQUIRY_DATA_PAGE			0x86
+#define INQ_BDEV_LIMITS_PAGE				0xB0
 #define INQ_BDEV_CHARACTERISTICS_PAGE			0xB1
 #define INQ_SERIAL_NUMBER_LENGTH			0x14
-#define INQ_NUM_SUPPORTED_VPD_PAGES			5
+#define INQ_NUM_SUPPORTED_VPD_PAGES			6
 #define VERSION_SPC_4					0x06
 #define ACA_UNSUPPORTED					0
 #define STANDARD_INQUIRY_LENGTH				36
@@ -747,6 +749,7 @@ static int nvme_trans_supported_vpd_pages(struct nvme_ns *ns,
 	inq_response[6] = INQ_DEVICE_IDENTIFICATION_PAGE;
 	inq_response[7] = INQ_EXTENDED_INQUIRY_DATA_PAGE;
 	inq_response[8] = INQ_BDEV_CHARACTERISTICS_PAGE;
+	inq_response[9] = INQ_BDEV_LIMITS_PAGE;
 
 	xfer_len = min(alloc_len, STANDARD_INQUIRY_LENGTH);
 	res = nvme_trans_copy_to_user(hdr, inq_response, xfer_len);
@@ -938,6 +941,25 @@ static int nvme_trans_ext_inq_page(struct nvme_ns *ns, struct sg_io_hdr *hdr,
 	return res;
 }
 
+static int nvme_trans_bdev_limits_page(struct nvme_ns *ns, struct sg_io_hdr *hdr,
+					u8 *inq_response, int alloc_len)
+{
+	__be32 max_sectors = cpu_to_be32(queue_max_hw_sectors(ns->queue));
+	__be32 max_discard = cpu_to_be32(ns->queue->limits.max_discard_sectors);
+	__be32 discard_desc_count = cpu_to_be32(0x100);
+
+	memset(inq_response, 0, STANDARD_INQUIRY_LENGTH);
+	inq_response[1] = VPD_BLOCK_LIMITS;
+	inq_response[3] = 0x3c; /* Page Length */
+	memcpy(&inq_response[8], &max_sectors, sizeof(u32));
+	memcpy(&inq_response[20], &max_discard, sizeof(u32));
+
+	if (max_discard)
+		memcpy(&inq_response[24], &discard_desc_count, sizeof(u32));
+
+	return nvme_trans_copy_to_user(hdr, inq_response, 0x3c);
+}
+
 static int nvme_trans_bdev_char_page(struct nvme_ns *ns, struct sg_io_hdr *hdr,
 					int alloc_len)
 {
@@ -2268,6 +2290,10 @@ static int nvme_trans_inquiry(struct nvme_ns *ns, struct sg_io_hdr *hdr,
 		case VPD_EXTENDED_INQUIRY:
 			res = nvme_trans_ext_inq_page(ns, hdr, alloc_len);
 			break;
+		case VPD_BLOCK_LIMITS:
+			res = nvme_trans_bdev_limits_page(ns, hdr, inq_response,
+								alloc_len);
+			break;
 		case VPD_BLOCK_DEV_CHARACTERISTICS:
 			res = nvme_trans_bdev_char_page(ns, hdr, alloc_len);
 			break;
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 2a04d341e598..bd2b3bbbb22c 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -34,6 +34,8 @@
  * IN THE SOFTWARE.
  */
 
+#define pr_fmt(fmt) "xen-blkback: " fmt
+
 #include <linux/spinlock.h>
 #include <linux/kthread.h>
 #include <linux/list.h>
@@ -211,7 +213,7 @@ static int add_persistent_gnt(struct xen_blkif *blkif,
 		else if (persistent_gnt->gnt > this->gnt)
 			new = &((*new)->rb_right);
 		else {
-			pr_alert_ratelimited(DRV_PFX " trying to add a gref that's already in the tree\n");
+			pr_alert_ratelimited("trying to add a gref that's already in the tree\n");
 			return -EINVAL;
 		}
 	}
@@ -242,7 +244,7 @@ static struct persistent_gnt *get_persistent_gnt(struct xen_blkif *blkif,
 			node = node->rb_right;
 		else {
 			if(test_bit(PERSISTENT_GNT_ACTIVE, data->flags)) {
-				pr_alert_ratelimited(DRV_PFX " requesting a grant already in use\n");
+				pr_alert_ratelimited("requesting a grant already in use\n");
 				return NULL;
 			}
 			set_bit(PERSISTENT_GNT_ACTIVE, data->flags);
@@ -257,7 +259,7 @@ static void put_persistent_gnt(struct xen_blkif *blkif,
                                struct persistent_gnt *persistent_gnt)
 {
 	if(!test_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags))
-	          pr_alert_ratelimited(DRV_PFX " freeing a grant already unused");
+		pr_alert_ratelimited("freeing a grant already unused\n");
 	set_bit(PERSISTENT_GNT_WAS_ACTIVE, persistent_gnt->flags);
 	clear_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags);
 	atomic_dec(&blkif->persistent_gnt_in_use);
@@ -374,7 +376,7 @@ static void purge_persistent_gnt(struct xen_blkif *blkif)
 	}
 
 	if (work_pending(&blkif->persistent_purge_work)) {
-		pr_alert_ratelimited(DRV_PFX "Scheduled work from previous purge is still pending, cannot purge list\n");
+		pr_alert_ratelimited("Scheduled work from previous purge is still pending, cannot purge list\n");
 		return;
 	}
 
@@ -396,7 +398,7 @@ static void purge_persistent_gnt(struct xen_blkif *blkif)
 
 	total = num_clean;
 
-	pr_debug(DRV_PFX "Going to purge %u persistent grants\n", num_clean);
+	pr_debug("Going to purge %u persistent grants\n", num_clean);
 
 	BUG_ON(!list_empty(&blkif->persistent_purge_list));
 	root = &blkif->persistent_gnts;
@@ -428,13 +430,13 @@ purge_list:
 	 * with the requested num
 	 */
 	if (!scan_used && !clean_used) {
-		pr_debug(DRV_PFX "Still missing %u purged frames\n", num_clean);
+		pr_debug("Still missing %u purged frames\n", num_clean);
 		scan_used = true;
 		goto purge_list;
 	}
 finished:
 	if (!clean_used) {
-		pr_debug(DRV_PFX "Finished scanning for grants to clean, removing used flag\n");
+		pr_debug("Finished scanning for grants to clean, removing used flag\n");
 		clean_used = true;
 		goto purge_list;
 	}
@@ -444,7 +446,7 @@ finished:
 
 	/* We can defer this work */
 	schedule_work(&blkif->persistent_purge_work);
-	pr_debug(DRV_PFX "Purged %u/%u\n", (total - num_clean), total);
+	pr_debug("Purged %u/%u\n", (total - num_clean), total);
 	return;
 }
 
@@ -520,20 +522,20 @@ static void xen_vbd_resize(struct xen_blkif *blkif)
 	struct xenbus_device *dev = xen_blkbk_xenbus(blkif->be);
 	unsigned long long new_size = vbd_sz(vbd);
 
-	pr_info(DRV_PFX "VBD Resize: Domid: %d, Device: (%d, %d)\n",
+	pr_info("VBD Resize: Domid: %d, Device: (%d, %d)\n",
 		blkif->domid, MAJOR(vbd->pdevice), MINOR(vbd->pdevice));
-	pr_info(DRV_PFX "VBD Resize: new size %llu\n", new_size);
+	pr_info("VBD Resize: new size %llu\n", new_size);
 	vbd->size = new_size;
 again:
 	err = xenbus_transaction_start(&xbt);
 	if (err) {
-		pr_warn(DRV_PFX "Error starting transaction");
+		pr_warn("Error starting transaction\n");
 		return;
 	}
 	err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
 			    (unsigned long long)vbd_sz(vbd));
 	if (err) {
-		pr_warn(DRV_PFX "Error writing new size");
+		pr_warn("Error writing new size\n");
 		goto abort;
 	}
 	/*
@@ -543,7 +545,7 @@ again:
 	 */
 	err = xenbus_printf(xbt, dev->nodename, "state", "%d", dev->state);
 	if (err) {
-		pr_warn(DRV_PFX "Error writing the state");
+		pr_warn("Error writing the state\n");
 		goto abort;
 	}
 
@@ -551,7 +553,7 @@ again:
 	if (err == -EAGAIN)
 		goto again;
 	if (err)
-		pr_warn(DRV_PFX "Error ending transaction");
+		pr_warn("Error ending transaction\n");
 	return;
 abort:
 	xenbus_transaction_end(xbt, 1);
@@ -578,7 +580,7 @@ irqreturn_t xen_blkif_be_int(int irq, void *dev_id)
 
 static void print_stats(struct xen_blkif *blkif)
 {
-	pr_info("xen-blkback (%s): oo %3llu  |  rd %4llu  |  wr %4llu  |  f %4llu"
+	pr_info("(%s): oo %3llu  |  rd %4llu  |  wr %4llu  |  f %4llu"
 		 "  |  ds %4llu | pg: %4u/%4d\n",
 		 current->comm, blkif->st_oo_req,
 		 blkif->st_rd_req, blkif->st_wr_req,
@@ -855,7 +857,7 @@ again:
 			/* This is a newly mapped grant */
 			BUG_ON(new_map_idx >= segs_to_map);
 			if (unlikely(map[new_map_idx].status != 0)) {
-				pr_debug(DRV_PFX "invalid buffer -- could not remap it\n");
+				pr_debug("invalid buffer -- could not remap it\n");
 				put_free_pages(blkif, &pages[seg_idx]->page, 1);
 				pages[seg_idx]->handle = BLKBACK_INVALID_HANDLE;
 				ret |= 1;
@@ -891,14 +893,14 @@ again:
 				goto next;
 			}
 			pages[seg_idx]->persistent_gnt = persistent_gnt;
-			pr_debug(DRV_PFX " grant %u added to the tree of persistent grants, using %u/%u\n",
+			pr_debug("grant %u added to the tree of persistent grants, using %u/%u\n",
 				 persistent_gnt->gnt, blkif->persistent_gnt_c,
 				 xen_blkif_max_pgrants);
 			goto next;
 		}
 		if (use_persistent_gnts && !blkif->vbd.overflow_max_grants) {
 			blkif->vbd.overflow_max_grants = 1;
-			pr_debug(DRV_PFX " domain %u, device %#x is using maximum number of persistent grants\n",
+			pr_debug("domain %u, device %#x is using maximum number of persistent grants\n",
 			         blkif->domid, blkif->vbd.handle);
 		}
 		/*
@@ -916,7 +918,7 @@ next:
 	return ret;
 
 out_of_memory:
-	pr_alert(DRV_PFX "%s: out of memory\n", __func__);
+	pr_alert("%s: out of memory\n", __func__);
 	put_free_pages(blkif, pages_to_gnt, segs_to_map);
 	return -ENOMEM;
 }
@@ -996,7 +998,7 @@ static int dispatch_discard_io(struct xen_blkif *blkif,
 
 	err = xen_vbd_translate(&preq, blkif, WRITE);
 	if (err) {
-		pr_warn(DRV_PFX "access denied: DISCARD [%llu->%llu] on dev=%04x\n",
+		pr_warn("access denied: DISCARD [%llu->%llu] on dev=%04x\n",
 			preq.sector_number,
 			preq.sector_number + preq.nr_sects, blkif->vbd.pdevice);
 		goto fail_response;
@@ -1012,7 +1014,7 @@ static int dispatch_discard_io(struct xen_blkif *blkif,
 				   GFP_KERNEL, secure);
 fail_response:
 	if (err == -EOPNOTSUPP) {
-		pr_debug(DRV_PFX "discard op failed, not supported\n");
+		pr_debug("discard op failed, not supported\n");
 		status = BLKIF_RSP_EOPNOTSUPP;
 	} else if (err)
 		status = BLKIF_RSP_ERROR;
@@ -1056,16 +1058,16 @@ static void __end_block_io_op(struct pending_req *pending_req, int error)
 	/* An error fails the entire request. */
 	if ((pending_req->operation == BLKIF_OP_FLUSH_DISKCACHE) &&
 	    (error == -EOPNOTSUPP)) {
-		pr_debug(DRV_PFX "flush diskcache op failed, not supported\n");
+		pr_debug("flush diskcache op failed, not supported\n");
 		xen_blkbk_flush_diskcache(XBT_NIL, pending_req->blkif->be, 0);
 		pending_req->status = BLKIF_RSP_EOPNOTSUPP;
 	} else if ((pending_req->operation == BLKIF_OP_WRITE_BARRIER) &&
 		    (error == -EOPNOTSUPP)) {
-		pr_debug(DRV_PFX "write barrier op failed, not supported\n");
+		pr_debug("write barrier op failed, not supported\n");
 		xen_blkbk_barrier(XBT_NIL, pending_req->blkif->be, 0);
 		pending_req->status = BLKIF_RSP_EOPNOTSUPP;
 	} else if (error) {
-		pr_debug(DRV_PFX "Buffer not up-to-date at end of operation,"
+		pr_debug("Buffer not up-to-date at end of operation,"
 			 " error=%d\n", error);
 		pending_req->status = BLKIF_RSP_ERROR;
 	}
@@ -1110,7 +1112,7 @@ __do_block_io_op(struct xen_blkif *blkif)
 
 	if (RING_REQUEST_PROD_OVERFLOW(&blk_rings->common, rp)) {
 		rc = blk_rings->common.rsp_prod_pvt;
-		pr_warn(DRV_PFX "Frontend provided bogus ring requests (%d - %d = %d). Halting ring processing on dev=%04x\n",
+		pr_warn("Frontend provided bogus ring requests (%d - %d = %d). Halting ring processing on dev=%04x\n",
 			rp, rc, rp - rc, blkif->vbd.pdevice);
 		return -EACCES;
 	}
@@ -1217,8 +1219,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
 	if ((req->operation == BLKIF_OP_INDIRECT) &&
 	    (req_operation != BLKIF_OP_READ) &&
 	    (req_operation != BLKIF_OP_WRITE)) {
-		pr_debug(DRV_PFX "Invalid indirect operation (%u)\n",
-			 req_operation);
+		pr_debug("Invalid indirect operation (%u)\n", req_operation);
 		goto fail_response;
 	}
 
@@ -1252,8 +1253,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
 		     (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) ||
 	    unlikely((req->operation == BLKIF_OP_INDIRECT) &&
 		     (nseg > MAX_INDIRECT_SEGMENTS))) {
-		pr_debug(DRV_PFX "Bad number of segments in request (%d)\n",
-			 nseg);
+		pr_debug("Bad number of segments in request (%d)\n", nseg);
 		/* Haven't submitted any bio's yet. */
 		goto fail_response;
 	}
@@ -1288,7 +1288,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
 	}
 
 	if (xen_vbd_translate(&preq, blkif, operation) != 0) {
-		pr_debug(DRV_PFX "access denied: %s of [%llu,%llu] on dev=%04x\n",
+		pr_debug("access denied: %s of [%llu,%llu] on dev=%04x\n",
 			 operation == READ ? "read" : "write",
 			 preq.sector_number,
 			 preq.sector_number + preq.nr_sects,
@@ -1303,7 +1303,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
 	for (i = 0; i < nseg; i++) {
 		if (((int)preq.sector_number|(int)seg[i].nsec) &
 		    ((bdev_logical_block_size(preq.bdev) >> 9) - 1)) {
-			pr_debug(DRV_PFX "Misaligned I/O request from domain %d",
+			pr_debug("Misaligned I/O request from domain %d\n",
 				 blkif->domid);
 			goto fail_response;
 		}
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index 375d28851860..f620b5d3f77c 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -44,12 +44,6 @@
 #include <xen/interface/io/blkif.h>
 #include <xen/interface/io/protocols.h>
 
-#define DRV_PFX "xen-blkback:"
-#define DPRINTK(fmt, args...)				\
-	pr_debug(DRV_PFX "(%s:%d) " fmt ".\n",		\
-		 __func__, __LINE__, ##args)
-
-
 /*
  * This is the maximum number of segments that would be allowed in indirect
  * requests. This value will also be passed to the frontend.
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index ff3025922c14..6ab69ad61ee1 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -14,6 +14,8 @@
 
 */
 
+#define pr_fmt(fmt) "xen-blkback: " fmt
+
 #include <stdarg.h>
 #include <linux/module.h>
 #include <linux/kthread.h>
@@ -21,6 +23,9 @@
 #include <xen/grant_table.h>
 #include "common.h"
 
+/* Enlarge the array size in order to fully show blkback name. */
+#define BLKBACK_NAME_LEN (20)
+
 struct backend_info {
 	struct xenbus_device	*dev;
 	struct xen_blkif	*blkif;
@@ -70,7 +75,7 @@ static int blkback_name(struct xen_blkif *blkif, char *buf)
 	else
 		devname  = devpath;
 
-	snprintf(buf, TASK_COMM_LEN, "blkback.%d.%s", blkif->domid, devname);
+	snprintf(buf, BLKBACK_NAME_LEN, "blkback.%d.%s", blkif->domid, devname);
 	kfree(devpath);
 
 	return 0;
@@ -79,7 +84,7 @@ static int blkback_name(struct xen_blkif *blkif, char *buf)
 static void xen_update_blkif_status(struct xen_blkif *blkif)
 {
 	int err;
-	char name[TASK_COMM_LEN];
+	char name[BLKBACK_NAME_LEN];
 
 	/* Not ready to connect? */
 	if (!blkif->irq || !blkif->vbd.bdev)
@@ -424,14 +429,14 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
 				 FMODE_READ : FMODE_WRITE, NULL);
 
 	if (IS_ERR(bdev)) {
-		DPRINTK("xen_vbd_create: device %08x could not be opened.\n",
+		pr_warn("xen_vbd_create: device %08x could not be opened\n",
 			vbd->pdevice);
 		return -ENOENT;
 	}
 
 	vbd->bdev = bdev;
 	if (vbd->bdev->bd_disk == NULL) {
-		DPRINTK("xen_vbd_create: device %08x doesn't exist.\n",
+		pr_warn("xen_vbd_create: device %08x doesn't exist\n",
 			vbd->pdevice);
 		xen_vbd_free(vbd);
 		return -ENOENT;
@@ -450,7 +455,7 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
 	if (q && blk_queue_secdiscard(q))
 		vbd->discard_secure = true;
 
-	DPRINTK("Successful creation of handle=%04x (dom=%u)\n",
+	pr_debug("Successful creation of handle=%04x (dom=%u)\n",
 		handle, blkif->domid);
 	return 0;
 }
@@ -458,7 +463,7 @@ static int xen_blkbk_remove(struct xenbus_device *dev)
 {
 	struct backend_info *be = dev_get_drvdata(&dev->dev);
 
-	DPRINTK("");
+	pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
 
 	if (be->major || be->minor)
 		xenvbd_sysfs_delif(dev);
@@ -564,6 +569,10 @@ static int xen_blkbk_probe(struct xenbus_device *dev,
 	int err;
 	struct backend_info *be = kzalloc(sizeof(struct backend_info),
 					  GFP_KERNEL);
+
+	/* match the pr_debug in xen_blkbk_remove */
+	pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
+
 	if (!be) {
 		xenbus_dev_fatal(dev, -ENOMEM,
 				 "allocating backend structure");
@@ -595,7 +604,7 @@ static int xen_blkbk_probe(struct xenbus_device *dev,
 	return 0;
 
 fail:
-	DPRINTK("failed");
+	pr_warn("%s failed\n", __func__);
 	xen_blkbk_remove(dev);
 	return err;
 }
@@ -619,7 +628,7 @@ static void backend_changed(struct xenbus_watch *watch,
 	unsigned long handle;
 	char *device_type;
 
-	DPRINTK("");
+	pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
 
 	err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x",
 			   &major, &minor);
@@ -638,7 +647,7 @@ static void backend_changed(struct xenbus_watch *watch,
 
 	if (be->major | be->minor) {
 		if (be->major != major || be->minor != minor)
-			pr_warn(DRV_PFX "changing physical device (from %x:%x to %x:%x) not supported.\n",
+			pr_warn("changing physical device (from %x:%x to %x:%x) not supported.\n",
 				be->major, be->minor, major, minor);
 		return;
 	}
@@ -699,13 +708,12 @@ static void frontend_changed(struct xenbus_device *dev,
 	struct backend_info *be = dev_get_drvdata(&dev->dev);
 	int err;
 
-	DPRINTK("%s", xenbus_strstate(frontend_state));
+	pr_debug("%s %p %s\n", __func__, dev, xenbus_strstate(frontend_state));
 
 	switch (frontend_state) {
 	case XenbusStateInitialising:
 		if (dev->state == XenbusStateClosed) {
-			pr_info(DRV_PFX "%s: prepare for reconnect\n",
-				dev->nodename);
+			pr_info("%s: prepare for reconnect\n", dev->nodename);
 			xenbus_switch_state(dev, XenbusStateInitWait);
 		}
 		break;
@@ -772,7 +780,7 @@ static void connect(struct backend_info *be)
 	int err;
 	struct xenbus_device *dev = be->dev;
 
-	DPRINTK("%s", dev->otherend);
+	pr_debug("%s %s\n", __func__, dev->otherend);
 
 	/* Supply the information about the device the frontend needs */
 again:
@@ -858,7 +866,7 @@ static int connect_ring(struct backend_info *be)
 	char protocol[64] = "";
 	int err;
 
-	DPRINTK("%s", dev->otherend);
+	pr_debug("%s %s\n", __func__, dev->otherend);
 
 	err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu",
 			    &ring_ref, "event-channel", "%u", &evtchn, NULL);
@@ -893,7 +901,7 @@ static int connect_ring(struct backend_info *be)
 	be->blkif->vbd.feature_gnt_persistent = pers_grants;
 	be->blkif->vbd.overflow_max_grants = 0;
 
-	pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d (%s) %s\n",
+	pr_info("ring-ref %ld, event-channel %d, protocol %d (%s) %s\n",
 		ring_ref, evtchn, be->blkif->blk_protocol, protocol,
 		pers_grants ? "persistent grants" : "");