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[PATCH 0/15] copy offload patches

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  [PATCH 0/15] copy offload patches Mikulas Patocka <mpatocka@redhat.com> - 2015-12-10 18:40 +0100
    [PATCH 7/15] scsi xcopy: keep cache of failures Mikulas Patocka <mpatocka@redhat.com> - 2015-12-10 18:40 +0100
    [PATCH 5/15] block copy: use asynchronous notification Mikulas Patocka <mpatocka@redhat.com> - 2015-12-10 18:40 +0100
    [PATCH 6/15] scsi xcopy: suppress error messages Mikulas Patocka <mpatocka@redhat.com> - 2015-12-10 18:40 +0100
    [PATCH 4/15] block copy: use a timer to fix a theoretical deadlock Mikulas Patocka <mpatocka@redhat.com> - 2015-12-10 18:40 +0100
    [PATCH 14/15] dm kcopyd: change mutex to spinlock Mikulas Patocka <mpatocka@redhat.com> - 2015-12-10 18:40 +0100
    [PATCH 9/15] dm: implement copy Mikulas Patocka <mpatocka@redhat.com> - 2015-12-10 18:40 +0100
    [PATCH 1/15] block copy: initial XCOPY offload support Mikulas Patocka <mpatocka@redhat.com> - 2015-12-10 18:40 +0100
    [PATCH 12/15] dm kcopyd: introduce the function submit_job Mikulas Patocka <mpatocka@redhat.com> - 2015-12-10 18:40 +0100
    Re: [PATCH 0/15] copy offload patches "Martin K. Petersen" <martin.petersen@oracle.com> - 2015-12-10 23:40 +0100
      Re: [dm-devel] [PATCH 0/15] copy offload patches Mike Christie <michaelc@cs.wisc.edu> - 2015-12-11 06:10 +0100
        Re: [dm-devel] [PATCH 0/15] copy offload patches Christoph Hellwig <hch@infradead.org> - 2015-12-11 21:00 +0100

#1288727 — [PATCH 0/15] copy offload patches

Hi

This patch series adds copy offload (the XCOPY command) to the block 
layer, SCSI subsystems and device mapper.

The principle of operation is this:

We create two bios with REQ_COPY flag, one for read and one for write. The 
bios have no data pages and they both point to the same bio_copy 
structure. The bios may be submitted to the same logical volume or to 
different logical volumes. The bios go independently through the device 
mapper stack and when they both reach the physical device (the function 
blk_queue_bio), the bio pair is collected and the XCOPY request is sent to 
the SCSI device.

Mikulas
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#1288728 — [PATCH 7/15] scsi xcopy: keep cache of failures

If xcopy between two devices fails, it is pointless to send more xcopy
command between there two devices because they take time and they will
likely also fail.

This patch keeps a cache of (source_device,destination_device) pairs where
copying failed and makes sure that no xcopy command is sooner than 30
seconds after the last failure.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

---
 drivers/scsi/sd.c |   37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

Index: linux-4.4-rc4/drivers/scsi/sd.c
===================================================================
--- linux-4.4-rc4.orig/drivers/scsi/sd.c	2015-12-07 16:59:09.000000000 +0100
+++ linux-4.4-rc4/drivers/scsi/sd.c	2015-12-07 16:59:12.000000000 +0100
@@ -939,6 +939,26 @@ static void sd_config_copy(struct scsi_d
 				   (logical_block_size >> 9));
 }
 
+#define SD_COPY_DISABLED_CACHE_TIME		(HZ * 30)
+#define SD_COPY_DISABLED_CACHE_HASH_BITS	6
+#define SD_COPY_DISABLED_CACHE_HASH		(1 << SD_COPY_DISABLED_CACHE_HASH_BITS)
+
+struct sd_copy_disabled_cache_entry {
+	struct scsi_device *src;
+	struct scsi_device *dst;
+	unsigned long jiffies;
+};
+
+static struct sd_copy_disabled_cache_entry sd_copy_disabled_cache[SD_COPY_DISABLED_CACHE_HASH];
+
+static struct sd_copy_disabled_cache_entry *sd_copy_disabled_cache_hash(
+	struct scsi_device *src, struct scsi_device *dst)
+{
+	return &sd_copy_disabled_cache[
+		hash_long((unsigned long)src + ((unsigned long)dst >> 1), SD_COPY_DISABLED_CACHE_HASH_BITS)
+	];
+}
+
 static int sd_setup_copy_cmnd(struct scsi_cmnd *cmd)
 {
 	struct request *rq = cmd->request;
@@ -951,6 +971,7 @@ static int sd_setup_copy_cmnd(struct scs
 	struct bio *bio = rq->bio;
 	struct page *page;
 	unsigned char *buf;
+	struct sd_copy_disabled_cache_entry *e;
 
 	dst_sdp = scsi_disk(rq->rq_disk)->device;
 	dst_queue = rq->rq_disk->queue;
@@ -970,6 +991,12 @@ static int sd_setup_copy_cmnd(struct scs
 	if (src_sdp->sector_size != dst_sdp->sector_size)
 		return BLKPREP_KILL;
 
+	/* The copy failed in the past, so do not retry it for some time */
+	e = sd_copy_disabled_cache_hash(src_sdp, dst_sdp);
+	if (unlikely(jiffies - ACCESS_ONCE(e->jiffies) < SD_COPY_DISABLED_CACHE_TIME) &&
+	    likely(ACCESS_ONCE(e->src) == src_sdp) && likely(ACCESS_ONCE(e->dst) == dst_sdp))
+		return BLKPREP_KILL;
+
 	dst_lba = blk_rq_pos(rq) >> (ilog2(dst_sdp->sector_size) - 9);
 	src_lba = bio->bi_copy->pair[0]->bi_iter.bi_sector >> (ilog2(src_sdp->sector_size) - 9);
 	nr_blocks = blk_rq_sectors(rq) >> (ilog2(dst_sdp->sector_size) - 9);
@@ -2003,6 +2030,16 @@ static int sd_done(struct scsi_cmnd *SCp
 			 */
 			case EXTENDED_COPY:
 				if ((SCpnt->cmnd[1] & 0x1f) == 0) {
+					struct sd_copy_disabled_cache_entry *e;
+					struct scsi_device *src_sdp, *dst_sdp;
+
+					dst_sdp = sdkp->device;
+					src_sdp = scsi_disk(req->bio->bi_copy->pair[0]->bi_bdev->bd_disk)->device;
+					e = sd_copy_disabled_cache_hash(src_sdp, dst_sdp);
+					ACCESS_ONCE(e->src) = src_sdp;
+					ACCESS_ONCE(e->dst) = dst_sdp;
+					ACCESS_ONCE(e->jiffies) = jiffies;
+
 					good_bytes = 0;
 					req->__data_len = blk_rq_bytes(req);
 					req->cmd_flags |= REQ_QUIET;
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#1288729 — [PATCH 5/15] block copy: use asynchronous notification

In dm-snapshot target there may be large number of copy requests in
progress. If every pending copy request consumed a process context, it
would put too much load on the system.

To avoid this load, we need asynchronous notification when copy finishes -
we can pass a callback to the function blkdev_issue_copy, if the callback
is non-NULL, blkdev_issue_copy exits when it submits all the copy bios and
the callback is called when the copy operation finishes.

With the callback mechanism, there can be large number of in-progress copy
requests and we do not need process context for each of them.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

---
 block/blk-lib.c           |  148 +++++++++++++++++++++++++++++++++-------------
 block/ioctl.c             |    2 
 include/linux/blk_types.h |    5 -
 include/linux/blkdev.h    |    2 
 4 files changed, 112 insertions(+), 45 deletions(-)

Index: linux-4.4-rc4/block/blk-lib.c
===================================================================
--- linux-4.4-rc4.orig/block/blk-lib.c	2015-12-10 17:04:45.000000000 +0100
+++ linux-4.4-rc4/block/blk-lib.c	2015-12-10 17:04:46.000000000 +0100
@@ -300,6 +300,17 @@ int blkdev_issue_zeroout(struct block_de
 }
 EXPORT_SYMBOL(blkdev_issue_zeroout);
 
+struct bio_copy_batch {
+	atomic_long_t done;
+	int async_error;
+	int sync_error;
+	sector_t sync_copied;
+	atomic64_t first_error;
+	void (*callback)(void *data, int error);
+	void *data;
+	sector_t *copied;
+};
+
 #define BLK_COPY_TIMEOUT	(10 * HZ)
 
 static void blk_copy_timeout(unsigned long bc_)
@@ -328,6 +339,18 @@ static void blk_copy_timeout(unsigned lo
 	}
 }
 
+static void blk_copy_batch_finish(struct bio_copy_batch *batch)
+{
+	void (*fn)(void *, int) = batch->callback;
+	void *data = batch->data;
+	int error = unlikely(batch->sync_error) ? batch->sync_error : batch->async_error;
+	if (batch->copied)
+		*batch->copied = min(batch->sync_copied, (sector_t)atomic64_read(&batch->first_error));
+	kfree(batch);
+	if (fn)
+		fn(data, error);
+}
+
 static void bio_copy_end_io(struct bio *bio)
 {
 	struct bio_copy *bc = bio->bi_copy;
@@ -351,25 +374,37 @@ static void bio_copy_end_io(struct bio *
 	}
 	bio_put(bio);
 	if (atomic_dec_and_test(&bc->in_flight)) {
-		struct bio_batch *bb = bc->private;
+		struct bio_copy_batch *batch = bc->batch;
 		if (unlikely(bc->error < 0)) {
 			u64 first_error;
-			if (!ACCESS_ONCE(bb->error))
-				ACCESS_ONCE(bb->error) = bc->error;
+			if (!ACCESS_ONCE(batch->async_error))
+				ACCESS_ONCE(batch->async_error) = bc->error;
 			do {
-				first_error = atomic64_read(bc->first_error);
+				first_error = atomic64_read(&batch->first_error);
 				if (bc->offset >= first_error)
 					break;
-			} while (unlikely(atomic64_cmpxchg(bc->first_error,
+			} while (unlikely(atomic64_cmpxchg(&batch->first_error,
 				first_error, bc->offset) != first_error));
 		}
 		del_timer_sync(&bc->timer);
 		kfree(bc);
-		if (atomic_dec_and_test(&bb->done))
-			complete(bb->wait);
+		if (atomic_long_dec_and_test(&batch->done))
+			blk_copy_batch_finish(batch);
 	}
 }
 
+struct bio_copy_completion {
+	struct completion wait;
+	int error;
+};
+
+static void bio_copy_sync_callback(void *ptr, int error)
+{
+	struct bio_copy_completion *comp = ptr;
+	comp->error = error;
+	complete(&comp->wait);
+}
+
 /**
  * blkdev_issue_copy - queue a copy same operation
  * @src_bdev:	source blockdev
@@ -384,57 +419,83 @@ static void bio_copy_end_io(struct bio *
  */
 int blkdev_issue_copy(struct block_device *src_bdev, sector_t src_sector,
 		      struct block_device *dst_bdev, sector_t dst_sector,
-		      sector_t nr_sects, gfp_t gfp_mask, sector_t *copied)
+		      sector_t nr_sects, gfp_t gfp_mask,
+		      void (*callback)(void *, int), void *data,
+		      sector_t *copied)
 {
 	DECLARE_COMPLETION_ONSTACK(wait);
 	struct request_queue *sq = bdev_get_queue(src_bdev);
 	struct request_queue *dq = bdev_get_queue(dst_bdev);
 	unsigned int max_copy_sectors;
-	struct bio_batch bb;
-	int ret = 0;
-	atomic64_t first_error = ATOMIC64_INIT(nr_sects);
-	sector_t offset = 0;
+	int ret;
+	struct bio_copy_batch *batch;
+	struct bio_copy_completion comp;
 
 	if (copied)
 		*copied = 0;
 
-	if (!sq || !dq)
-		return -ENXIO;
+	if (!sq || !dq) {
+		ret = -ENXIO;
+		goto end_callback;
+	}
 
 	max_copy_sectors = min(sq->limits.max_copy_sectors,
 			       dq->limits.max_copy_sectors);
 
-	if (max_copy_sectors == 0)
-		return -EOPNOTSUPP;
+	if (max_copy_sectors == 0) {
+		ret = -EOPNOTSUPP;
+		goto end_callback;
+	}
 
 	if (src_sector + nr_sects < src_sector ||
-	    dst_sector + nr_sects < dst_sector)
-		return -EINVAL;
+	    dst_sector + nr_sects < dst_sector) {
+		ret = -EINVAL;
+		goto end_callback;
+	}
 
 	/* Do not support overlapping copies */
 	if (src_bdev == dst_bdev &&
-	    abs((u64)dst_sector - (u64)src_sector) < nr_sects)
-		return -EOPNOTSUPP;
+	    abs((u64)dst_sector - (u64)src_sector) < nr_sects) {
+		ret = -EOPNOTSUPP;
+		goto end_callback;
+	}
 
-	atomic_set(&bb.done, 1);
-	bb.error = 0;
-	bb.wait = &wait;
+	batch = kmalloc(sizeof(struct bio_copy_batch), gfp_mask);
+	if (!batch) {
+		ret = -ENOMEM;
+		goto end_callback;
+	}
+
+	batch->done = (atomic_long_t)ATOMIC_LONG_INIT(1);
+	batch->async_error = 0;
+	batch->sync_error = 0;
+	batch->sync_copied = 0;
+	batch->first_error = (atomic64_t)ATOMIC64_INIT(nr_sects);
+	batch->copied = copied;
+	if (callback) {
+		batch->callback = callback;
+		batch->data = data;
+	} else {
+		comp.wait = COMPLETION_INITIALIZER_ONSTACK(comp.wait);
+		batch->callback = bio_copy_sync_callback;
+		batch->data = &comp;
+	}
 
-	while (nr_sects && !ACCESS_ONCE(bb.error)) {
+	while (nr_sects && !ACCESS_ONCE(batch->async_error)) {
 		struct bio *read_bio, *write_bio;
 		struct bio_copy *bc;
 		unsigned chunk = (unsigned)min(nr_sects, (sector_t)max_copy_sectors);
 
 		bc = kmalloc(sizeof(struct bio_copy), gfp_mask);
 		if (!bc) {
-			ret = -ENOMEM;
+			batch->sync_error = -ENOMEM;
 			break;
 		}
 
 		read_bio = bio_alloc(gfp_mask, 1);
 		if (!read_bio) {
 			kfree(bc);
-			ret = -ENOMEM;
+			batch->sync_error = -ENOMEM;
 			break;
 		}
 
@@ -442,7 +503,7 @@ int blkdev_issue_copy(struct block_devic
 		if (!write_bio) {
 			bio_put(read_bio);
 			kfree(bc);
-			ret = -ENOMEM;
+			batch->sync_error = -ENOMEM;
 			break;
 		}
 
@@ -450,9 +511,8 @@ int blkdev_issue_copy(struct block_devic
 		bc->error = 1;
 		bc->pair[0] = NULL;
 		bc->pair[1] = NULL;
-		bc->private = &bb;
-		bc->first_error = &first_error;
-		bc->offset = offset;
+		bc->batch = batch;
+		bc->offset = batch->sync_copied;
 		spin_lock_init(&bc->spinlock);
 		__setup_timer(&bc->timer, blk_copy_timeout, (unsigned long)bc, TIMER_IRQSAFE);
 		mod_timer(&bc->timer, jiffies + BLK_COPY_TIMEOUT);
@@ -469,27 +529,33 @@ int blkdev_issue_copy(struct block_devic
 		write_bio->bi_bdev = dst_bdev;
 		write_bio->bi_copy = bc;
 
-		atomic_inc(&bb.done);
+		atomic_long_inc(&batch->done);
 		submit_bio(READ | REQ_COPY, read_bio);
 		submit_bio(WRITE | REQ_COPY, write_bio);
 
 		src_sector += chunk;
 		dst_sector += chunk;
 		nr_sects -= chunk;
-		offset += chunk;
+		batch->sync_copied += chunk;
 	}
 
-	/* Wait for bios in-flight */
-	if (!atomic_dec_and_test(&bb.done))
-		wait_for_completion_io(&wait);
+	if (atomic_long_dec_and_test(&batch->done))
+		blk_copy_batch_finish(batch);
 
-	if (copied)
-		*copied = min((sector_t)atomic64_read(&first_error), offset);
-
-	if (likely(!ret))
-		ret = bb.error;
+	if (callback) {
+		return 0;
+	} else {
+		wait_for_completion_io(&comp.wait);
+		return comp.error;
+	}
 
-	return ret;
+end_callback:
+	if (callback) {
+		callback(data, ret);
+		return 0;
+	} else {
+		return ret;
+	}
 }
 EXPORT_SYMBOL(blkdev_issue_copy);
 
Index: linux-4.4-rc4/include/linux/blk_types.h
===================================================================
--- linux-4.4-rc4.orig/include/linux/blk_types.h	2015-12-10 17:04:45.000000000 +0100
+++ linux-4.4-rc4/include/linux/blk_types.h	2015-12-10 17:04:46.000000000 +0100
@@ -40,6 +40,8 @@ struct bvec_iter {
 						   current bvec */
 };
 
+struct bio_copy_batch;
+
 struct bio_copy {
 	/*
 	 * error == 1 - bios are waiting to be paired
@@ -49,8 +51,7 @@ struct bio_copy {
 	int error;
 	atomic_t in_flight;
 	struct bio *pair[2];
-	void *private;
-	atomic64_t *first_error;
+	struct bio_copy_batch *batch;
 	sector_t offset;
 	spinlock_t spinlock;
 	struct timer_list timer;
Index: linux-4.4-rc4/include/linux/blkdev.h
===================================================================
--- linux-4.4-rc4.orig/include/linux/blkdev.h	2015-12-10 17:04:40.000000000 +0100
+++ linux-4.4-rc4/include/linux/blkdev.h	2015-12-10 17:04:46.000000000 +0100
@@ -1142,7 +1142,7 @@ extern int blkdev_issue_write_same(struc
 		sector_t nr_sects, gfp_t gfp_mask, struct page *page);
 extern int blkdev_issue_copy(struct block_device *, sector_t,
 		struct block_device *, sector_t, sector_t, gfp_t,
-		sector_t *);
+		void (*)(void *, int), void *, sector_t *);
 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 		sector_t nr_sects, gfp_t gfp_mask, bool discard);
 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
Index: linux-4.4-rc4/block/ioctl.c
===================================================================
--- linux-4.4-rc4.orig/block/ioctl.c	2015-12-10 17:04:40.000000000 +0100
+++ linux-4.4-rc4/block/ioctl.c	2015-12-10 17:04:46.000000000 +0100
@@ -276,7 +276,7 @@ static int blk_ioctl_copy(struct block_d
 		return -EINVAL;
 
 	ret = blkdev_issue_copy(bdev, src_offset, bdev, dst_offset, len,
-				GFP_KERNEL, &copied_sec);
+				GFP_KERNEL, NULL, NULL, &copied_sec);
 
 	*copied = (uint64_t)copied_sec << 9;
 

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#1288731 — [PATCH 6/15] scsi xcopy: suppress error messages

This patch suppresses error messages when copying between two arrays that
support XCOPY each, but that cannot copy data between each other.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

---
 drivers/scsi/sd.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

Index: linux-4.4-rc4/drivers/scsi/sd.c
===================================================================
--- linux-4.4-rc4.orig/drivers/scsi/sd.c	2015-12-07 16:58:48.000000000 +0100
+++ linux-4.4-rc4/drivers/scsi/sd.c	2015-12-07 16:59:09.000000000 +0100
@@ -1995,6 +1995,20 @@ static int sd_done(struct scsi_cmnd *SCp
 					req->cmd_flags |= REQ_QUIET;
 				}
 			}
+		} else if (sshdr.asc == 0x26) {
+			switch (op) {
+			/*
+			 * Copying between two arrays that support XCOPY, but
+			 * cannot access each other.
+			 */
+			case EXTENDED_COPY:
+				if ((SCpnt->cmnd[1] & 0x1f) == 0) {
+					good_bytes = 0;
+					req->__data_len = blk_rq_bytes(req);
+					req->cmd_flags |= REQ_QUIET;
+				}
+				break;
+			}
 		}
 		break;
 	default:

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#1288732 — [PATCH 4/15] block copy: use a timer to fix a theoretical deadlock

The block layer creates two bios for each copy operation. The bios travel
independently through the storage stack and they are paired at the block
device.

There is a theoretical problem with this - the block device stack only
guarantees forward progress for a single bio. When two bios are sent, it
is possible (though very unlikely) that the first bio exhausts some
mempool and the second bio waits until there is free space in the mempool
(and thus it waits until the first bio finishes).

To avoid this deadlock, we introduce a timer. If the two bios are not
paired at the physical block device within 10 seconds, the copy operation
is aborted and the bio that waits to be paired is released with an error.

Note that there is no guarantee that any XCOPY operation succeed, so
aborting an operation with an error shouldn't cause any problems - the
caller is supposed to perform the copy manually if XCOPY fails.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

---
 block/blk-lib.c           |   31 +++++++++++++++++++++++++++++++
 include/linux/blk_types.h |    2 ++
 2 files changed, 33 insertions(+)

Index: linux-4.3/block/blk-lib.c
===================================================================
--- linux-4.3.orig/block/blk-lib.c	2015-11-02 18:43:06.000000000 +0100
+++ linux-4.3/block/blk-lib.c	2015-11-02 18:43:10.000000000 +0100
@@ -300,6 +300,34 @@ int blkdev_issue_zeroout(struct block_de
 }
 EXPORT_SYMBOL(blkdev_issue_zeroout);
 
+#define BLK_COPY_TIMEOUT	(10 * HZ)
+
+static void blk_copy_timeout(unsigned long bc_)
+{
+	struct bio_copy *bc = (struct bio_copy *)bc_;
+	struct bio *bio0 = NULL, *bio1 = NULL;
+
+	WARN_ON(!irqs_disabled());
+
+	spin_lock(&bc->spinlock);	/* the timer is IRQSAFE */
+	if (bc->error == 1) {
+		bc->error = -ETIMEDOUT;
+		bio0 = bc->pair[0];
+		bio1 = bc->pair[1];
+		bc->pair[0] = bc->pair[1] = NULL;
+	}
+	spin_unlock(&bc->spinlock);
+
+	if (bio0) {
+		bio0->bi_error = -ETIMEDOUT;
+		bio_endio(bio0);
+	}
+	if (bio1) {
+		bio1->bi_error = -ETIMEDOUT;
+		bio_endio(bio1);
+	}
+}
+
 static void bio_copy_end_io(struct bio *bio)
 {
 	struct bio_copy *bc = bio->bi_copy;
@@ -335,6 +363,7 @@ static void bio_copy_end_io(struct bio *
 			} while (unlikely(atomic64_cmpxchg(bc->first_error,
 				first_error, bc->offset) != first_error));
 		}
+		del_timer_sync(&bc->timer);
 		kfree(bc);
 		if (atomic_dec_and_test(&bb->done))
 			complete(bb->wait);
@@ -425,6 +454,8 @@ int blkdev_issue_copy(struct block_devic
 		bc->first_error = &first_error;
 		bc->offset = offset;
 		spin_lock_init(&bc->spinlock);
+		__setup_timer(&bc->timer, blk_copy_timeout, (unsigned long)bc, TIMER_IRQSAFE);
+		mod_timer(&bc->timer, jiffies + BLK_COPY_TIMEOUT);
 
 		read_bio->bi_iter.bi_sector = src_sector;
 		read_bio->bi_iter.bi_size = chunk << 9;
Index: linux-4.3/include/linux/blk_types.h
===================================================================
--- linux-4.3.orig/include/linux/blk_types.h	2015-11-02 18:43:06.000000000 +0100
+++ linux-4.3/include/linux/blk_types.h	2015-11-02 18:43:10.000000000 +0100
@@ -6,6 +6,7 @@
 #define __LINUX_BLK_TYPES_H
 
 #include <linux/types.h>
+#include <linux/timer.h>
 
 struct bio_set;
 struct bio;
@@ -52,6 +53,7 @@ struct bio_copy {
 	atomic64_t *first_error;
 	sector_t offset;
 	spinlock_t spinlock;
+	struct timer_list timer;
 };
 
 /*

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#1288734 — [PATCH 14/15] dm kcopyd: change mutex to spinlock

job->lock is only taken for a finite amount of time and the process
doesn't block while holding it, so change it from mutex to spinlock.

This change is needed for the next patch that makes it possible to call
segment_complete from an interrupt. Taking mutexes inside an interrupt is
not allowed.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

---
 drivers/md/dm-kcopyd.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

Index: linux-3.16-rc5/drivers/md/dm-kcopyd.c
===================================================================
--- linux-3.16-rc5.orig/drivers/md/dm-kcopyd.c	2014-07-15 19:20:34.000000000 +0200
+++ linux-3.16-rc5/drivers/md/dm-kcopyd.c	2014-07-15 19:24:20.000000000 +0200
@@ -21,7 +21,7 @@
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/workqueue.h>
-#include <linux/mutex.h>
+#include <linux/spinlock.h>
 #include <linux/delay.h>
 #include <linux/device-mapper.h>
 #include <linux/dm-kcopyd.h>
@@ -356,7 +356,7 @@ struct kcopyd_job {
 	 * These fields are only used if the job has been split
 	 * into more manageable parts.
 	 */
-	struct mutex lock;
+	spinlock_t lock;
 	atomic_t sub_jobs;
 	sector_t progress;
 
@@ -629,7 +629,7 @@ static void segment_complete(int read_er
 	struct kcopyd_job *job = sub_job->master_job;
 	struct dm_kcopyd_client *kc = job->kc;
 
-	mutex_lock(&job->lock);
+	spin_lock(&job->lock);
 
 	/* update the error */
 	if (read_err)
@@ -653,7 +653,7 @@ static void segment_complete(int read_er
 			job->progress += count;
 		}
 	}
-	mutex_unlock(&job->lock);
+	spin_unlock(&job->lock);
 
 	if (count) {
 		int i;
@@ -708,7 +708,7 @@ static void submit_job(struct kcopyd_job
 	if (job->source.count <= SUB_JOB_SIZE)
 		dispatch_job(job);
 	else {
-		mutex_init(&job->lock);
+		spin_lock_init(&job->lock);
 		job->progress = 0;
 		split_job(job);
 	}

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#1288735 — [PATCH 9/15] dm: implement copy

This patch implements basic copy support for device mapper core.
Individual targets can enable copy support by setting ti->copy_supported.

Device mapper device advertises copy support if at least one target
supports copy and for this target, at least one underlying device supports
copy.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

---
 drivers/md/dm-table.c         |   16 ++++++++++++++++
 drivers/md/dm.c               |   27 +++++++++++++++++++++++++++
 include/linux/device-mapper.h |    5 +++++
 3 files changed, 48 insertions(+)

Index: linux-4.4-rc4/drivers/md/dm.c
===================================================================
--- linux-4.4-rc4.orig/drivers/md/dm.c	2015-12-10 17:04:05.000000000 +0100
+++ linux-4.4-rc4/drivers/md/dm.c	2015-12-10 17:05:48.000000000 +0100
@@ -1679,6 +1679,31 @@ static int __send_write_same(struct clon
 	return __send_changing_extent_only(ci, get_num_write_same_bios, NULL);
 }
 
+static int __send_copy(struct clone_info *ci)
+{
+	struct dm_target *ti;
+	sector_t bound;
+
+	ti = dm_table_find_target(ci->map, ci->sector);
+	if (!dm_target_is_valid(ti))
+		return -EIO;
+
+	if (!ti->copy_supported)
+		return -EOPNOTSUPP;
+
+	bound = max_io_len(ci->sector, ti);
+
+	if (unlikely(ci->sector_count > bound))
+		return -EOPNOTSUPP;
+
+	__clone_and_map_simple_bio(ci, ti, 0, NULL);
+
+	ci->sector += ci->sector_count;
+	ci->sector_count = 0;
+
+	return 0;
+}
+
 /*
  * Select the correct strategy for processing a non-flush bio.
  */
@@ -1692,6 +1717,8 @@ static int __split_and_process_non_flush
 		return __send_discard(ci);
 	else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
 		return __send_write_same(ci);
+	else if (unlikely(bio->bi_rw & REQ_COPY))
+		return __send_copy(ci);
 
 	ti = dm_table_find_target(ci->map, ci->sector);
 	if (!dm_target_is_valid(ti))
Index: linux-4.4-rc4/include/linux/device-mapper.h
===================================================================
--- linux-4.4-rc4.orig/include/linux/device-mapper.h	2015-12-10 17:04:05.000000000 +0100
+++ linux-4.4-rc4/include/linux/device-mapper.h	2015-12-10 17:04:59.000000000 +0100
@@ -271,6 +271,11 @@ struct dm_target {
 	 * Set if this target does not return zeroes on discarded blocks.
 	 */
 	bool discard_zeroes_data_unsupported:1;
+
+	/*
+	 * Set if the target supports XCOPY.
+	 */
+	bool copy_supported:1;
 };
 
 /* Each target can link one of these into the table */
Index: linux-4.4-rc4/drivers/md/dm-table.c
===================================================================
--- linux-4.4-rc4.orig/drivers/md/dm-table.c	2015-12-10 17:03:51.000000000 +0100
+++ linux-4.4-rc4/drivers/md/dm-table.c	2015-12-10 17:04:59.000000000 +0100
@@ -286,6 +286,11 @@ static int device_area_is_invalid(struct
 		limits->logical_block_size >> SECTOR_SHIFT;
 	char b[BDEVNAME_SIZE];
 
+	if (ti->copy_supported)
+		limits->max_copy_sectors =
+			min_not_zero(limits->max_copy_sectors,
+				bdev_get_queue(bdev)->limits.max_copy_sectors);
+
 	/*
 	 * Some devices exist without request functions,
 	 * such as loop devices not yet bound to backing files.
@@ -1256,6 +1261,13 @@ int dm_calculate_queue_limits(struct dm_
 
 		ti = dm_table_get_target(table, i++);
 
+		if (ti->begin)
+			ti_limits.copy_boundary = min(ti_limits.copy_boundary,
+					(unsigned char)__ffs64(ti->begin));
+		if (ti->max_io_len)
+			ti_limits.copy_boundary = min(ti_limits.copy_boundary,
+					(unsigned char)__ffs(ti->max_io_len));
+
 		if (!ti->type->iterate_devices)
 			goto combine_limits;
 
@@ -1289,6 +1301,10 @@ combine_limits:
 			       dm_device_name(table->md),
 			       (unsigned long long) ti->begin,
 			       (unsigned long long) ti->len);
+
+		limits->max_copy_sectors =
+					min_not_zero(limits->max_copy_sectors,
+					ti_limits.max_copy_sectors);
 	}
 
 	return validate_hardware_logical_block_alignment(table, limits);

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#1288737 — [PATCH 1/15] block copy: initial XCOPY offload support

This is Martin Petersen's xcopy patch
(https://git.kernel.org/cgit/linux/kernel/git/mkp/linux.git/commit/?h=xcopy&id=0bdeed274e16b3038a851552188512071974eea8)
with some bug fixes, ported to the current kernel.

This patch makes it possible to use the SCSI XCOPY command.

We create a bio that has REQ_COPY flag in bi_rw and a bi_copy structure
that defines the source device. The target device is defined in the
bi_bdev and bi_iter.bi_sector.

There is a new BLKCOPY ioctl that makes it possible to use XCOPY from
userspace. The ioctl argument is a pointer to an array of four uint64_t
values.

The first value is a source byte offset, the second value is a destination
byte offset, the third value is byte length. The forth value is written by
the kernel and it represents the number of bytes that the kernel actually
copied.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

---
 Documentation/ABI/testing/sysfs-block |    9 +
 block/bio.c                           |    2 
 block/blk-core.c                      |    5 
 block/blk-lib.c                       |   95 +++++++++++
 block/blk-merge.c                     |   11 -
 block/blk-settings.c                  |   13 +
 block/blk-sysfs.c                     |   11 +
 block/compat_ioctl.c                  |    1 
 block/ioctl.c                         |   50 ++++++
 drivers/scsi/scsi.c                   |   57 +++++++
 drivers/scsi/sd.c                     |  271 +++++++++++++++++++++++++++++++++-
 drivers/scsi/sd.h                     |    4 
 include/linux/bio.h                   |    9 -
 include/linux/blk_types.h             |   14 +
 include/linux/blkdev.h                |   15 +
 include/scsi/scsi_device.h            |    3 
 include/uapi/linux/fs.h               |    1 
 17 files changed, 557 insertions(+), 14 deletions(-)

Index: linux-4.4-rc4/Documentation/ABI/testing/sysfs-block
===================================================================
--- linux-4.4-rc4.orig/Documentation/ABI/testing/sysfs-block	2015-12-10 17:03:59.000000000 +0100
+++ linux-4.4-rc4/Documentation/ABI/testing/sysfs-block	2015-12-10 17:04:30.000000000 +0100
@@ -235,3 +235,12 @@ Description:
 		write_same_max_bytes is 0, write same is not supported
 		by the device.
 
+
+What:		/sys/block/<disk>/queue/copy_max_bytes
+Date:		January 2014
+Contact:	Martin K. Petersen <martin.petersen@oracle.com>
+Description:
+		Devices that support copy offloading will set this value
+		to indicate the maximum buffer size in bytes that can be
+		copied in one operation. If the copy_max_bytes is 0 the
+		device does not support copy offload.
Index: linux-4.4-rc4/block/blk-core.c
===================================================================
--- linux-4.4-rc4.orig/block/blk-core.c	2015-12-10 17:03:59.000000000 +0100
+++ linux-4.4-rc4/block/blk-core.c	2015-12-10 17:04:30.000000000 +0100
@@ -1957,6 +1957,11 @@ generic_make_request_checks(struct bio *
 		goto end_io;
 	}
 
+	if (bio->bi_rw & REQ_COPY && !bdev_copy_offload(bio->bi_bdev)) {
+		err = -EOPNOTSUPP;
+		goto end_io;
+	}
+
 	/*
 	 * Various block parts want %current->io_context and lazy ioc
 	 * allocation ends up trading a lot of pain for a small amount of
Index: linux-4.4-rc4/block/blk-lib.c
===================================================================
--- linux-4.4-rc4.orig/block/blk-lib.c	2015-12-10 17:03:59.000000000 +0100
+++ linux-4.4-rc4/block/blk-lib.c	2015-12-10 17:04:30.000000000 +0100
@@ -299,3 +299,98 @@ int blkdev_issue_zeroout(struct block_de
 	return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
 }
 EXPORT_SYMBOL(blkdev_issue_zeroout);
+
+/**
+ * blkdev_issue_copy - queue a copy same operation
+ * @src_bdev:	source blockdev
+ * @src_sector:	source sector
+ * @dst_bdev:	destination blockdev
+ * @dst_sector: destination sector
+ * @nr_sects:	number of sectors to copy
+ * @gfp_mask:	memory allocation flags (for bio_alloc)
+ *
+ * Description:
+ *    Copy a block range from source device to target device.
+ */
+int blkdev_issue_copy(struct block_device *src_bdev, sector_t src_sector,
+		      struct block_device *dst_bdev, sector_t dst_sector,
+		      unsigned int nr_sects, gfp_t gfp_mask)
+{
+	DECLARE_COMPLETION_ONSTACK(wait);
+	struct request_queue *sq = bdev_get_queue(src_bdev);
+	struct request_queue *dq = bdev_get_queue(dst_bdev);
+	unsigned int max_copy_sectors;
+	struct bio_batch bb;
+	int ret = 0;
+
+	if (!sq || !dq)
+		return -ENXIO;
+
+	max_copy_sectors = min(sq->limits.max_copy_sectors,
+			       dq->limits.max_copy_sectors);
+
+	if (max_copy_sectors == 0)
+		return -EOPNOTSUPP;
+
+	if (src_sector + nr_sects < src_sector ||
+	    dst_sector + nr_sects < dst_sector)
+		return -EINVAL;
+
+	/* Do not support overlapping copies */
+	if (src_bdev == dst_bdev &&
+	    abs((u64)dst_sector - (u64)src_sector) < nr_sects)
+		return -EOPNOTSUPP;
+
+	atomic_set(&bb.done, 1);
+	bb.error = 0;
+	bb.wait = &wait;
+
+	while (nr_sects) {
+		struct bio *bio;
+		struct bio_copy *bc;
+		unsigned int chunk;
+
+		bc = kmalloc(sizeof(struct bio_copy), gfp_mask);
+		if (!bc) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		bio = bio_alloc(gfp_mask, 1);
+		if (!bio) {
+			kfree(bc);
+			ret = -ENOMEM;
+			break;
+		}
+
+		chunk = min(nr_sects, max_copy_sectors);
+
+		bio->bi_iter.bi_sector = dst_sector;
+		bio->bi_iter.bi_size = chunk << 9;
+		bio->bi_end_io = bio_batch_end_io;
+		bio->bi_bdev = dst_bdev;
+		bio->bi_private = &bb;
+		bio->bi_copy = bc;
+
+		bc->bic_bdev = src_bdev;
+		bc->bic_sector = src_sector;
+
+		atomic_inc(&bb.done);
+		submit_bio(REQ_WRITE | REQ_COPY, bio);
+
+		src_sector += chunk;
+		dst_sector += chunk;
+		nr_sects -= chunk;
+	}
+
+	/* Wait for bios in-flight */
+	if (!atomic_dec_and_test(&bb.done))
+		wait_for_completion_io(&wait);
+
+	if (likely(!ret))
+		ret = bb.error;
+
+	return ret;
+}
+EXPORT_SYMBOL(blkdev_issue_copy);
+
Index: linux-4.4-rc4/block/blk-merge.c
===================================================================
--- linux-4.4-rc4.orig/block/blk-merge.c	2015-12-10 17:03:59.000000000 +0100
+++ linux-4.4-rc4/block/blk-merge.c	2015-12-10 17:04:30.000000000 +0100
@@ -145,7 +145,9 @@ void blk_queue_split(struct request_queu
 	struct bio *split, *res;
 	unsigned nsegs;
 
-	if ((*bio)->bi_rw & REQ_DISCARD)
+	if ((*bio)->bi_rw & REQ_COPY)
+		return;
+	else if ((*bio)->bi_rw & REQ_DISCARD)
 		split = blk_bio_discard_split(q, *bio, bs, &nsegs);
 	else if ((*bio)->bi_rw & REQ_WRITE_SAME)
 		split = blk_bio_write_same_split(q, *bio, bs, &nsegs);
@@ -185,10 +187,7 @@ static unsigned int __blk_recalc_rq_segm
 	 * This should probably be returning 0, but blk_add_request_payload()
 	 * (Christoph!!!!)
 	 */
-	if (bio->bi_rw & REQ_DISCARD)
-		return 1;
-
-	if (bio->bi_rw & REQ_WRITE_SAME)
+	if (bio->bi_rw & (REQ_DISCARD | REQ_WRITE_SAME | REQ_COPY))
 		return 1;
 
 	fbio = bio;
@@ -361,7 +360,7 @@ static int __blk_bios_map_sg(struct requ
 	nsegs = 0;
 	cluster = blk_queue_cluster(q);
 
-	if (bio->bi_rw & REQ_DISCARD) {
+	if (bio->bi_rw & (REQ_DISCARD | REQ_COPY)) {
 		/*
 		 * This is a hack - drivers should be neither modifying the
 		 * biovec, nor relying on bi_vcnt - but because of
Index: linux-4.4-rc4/block/blk-settings.c
===================================================================
--- linux-4.4-rc4.orig/block/blk-settings.c	2015-12-10 17:03:59.000000000 +0100
+++ linux-4.4-rc4/block/blk-settings.c	2015-12-10 17:04:30.000000000 +0100
@@ -95,6 +95,7 @@ void blk_set_default_limits(struct queue
 		BLK_SAFE_MAX_SECTORS;
 	lim->chunk_sectors = 0;
 	lim->max_write_same_sectors = 0;
+	lim->max_copy_sectors = 0;
 	lim->max_discard_sectors = 0;
 	lim->max_hw_discard_sectors = 0;
 	lim->discard_granularity = 0;
@@ -298,6 +299,18 @@ void blk_queue_max_write_same_sectors(st
 EXPORT_SYMBOL(blk_queue_max_write_same_sectors);
 
 /**
+ * blk_queue_max_copy_sectors - set max sectors for a single copy operation
+ * @q:  the request queue for the device
+ * @max_copy_sectors: maximum number of sectors per copy operation
+ **/
+void blk_queue_max_copy_sectors(struct request_queue *q,
+				unsigned int max_copy_sectors)
+{
+	q->limits.max_copy_sectors = max_copy_sectors;
+}
+EXPORT_SYMBOL(blk_queue_max_copy_sectors);
+
+/**
  * blk_queue_max_segments - set max hw segments for a request for this queue
  * @q:  the request queue for the device
  * @max_segments:  max number of segments
Index: linux-4.4-rc4/block/blk-sysfs.c
===================================================================
--- linux-4.4-rc4.orig/block/blk-sysfs.c	2015-12-10 17:04:01.000000000 +0100
+++ linux-4.4-rc4/block/blk-sysfs.c	2015-12-10 17:04:30.000000000 +0100
@@ -193,6 +193,11 @@ static ssize_t queue_write_same_max_show
 		(unsigned long long)q->limits.max_write_same_sectors << 9);
 }
 
+static ssize_t queue_copy_max_show(struct request_queue *q, char *page)
+{
+	return sprintf(page, "%llu\n",
+		(unsigned long long)q->limits.max_copy_sectors << 9);
+}
 
 static ssize_t
 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
@@ -443,6 +448,11 @@ static struct queue_sysfs_entry queue_wr
 	.show = queue_write_same_max_show,
 };
 
+static struct queue_sysfs_entry queue_copy_max_entry = {
+	.attr = {.name = "copy_max_bytes", .mode = S_IRUGO },
+	.show = queue_copy_max_show,
+};
+
 static struct queue_sysfs_entry queue_nonrot_entry = {
 	.attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 	.show = queue_show_nonrot,
@@ -498,6 +508,7 @@ static struct attribute *default_attrs[]
 	&queue_discard_max_hw_entry.attr,
 	&queue_discard_zeroes_data_entry.attr,
 	&queue_write_same_max_entry.attr,
+	&queue_copy_max_entry.attr,
 	&queue_nonrot_entry.attr,
 	&queue_nomerges_entry.attr,
 	&queue_rq_affinity_entry.attr,
Index: linux-4.4-rc4/block/ioctl.c
===================================================================
--- linux-4.4-rc4.orig/block/ioctl.c	2015-12-10 17:03:59.000000000 +0100
+++ linux-4.4-rc4/block/ioctl.c	2015-12-10 17:04:30.000000000 +0100
@@ -249,6 +249,31 @@ static int blk_ioctl_zeroout(struct bloc
 	return blkdev_issue_zeroout(bdev, start, len, GFP_KERNEL, false);
 }
 
+static int blk_ioctl_copy(struct block_device *bdev, uint64_t src_offset,
+			  uint64_t dst_offset, uint64_t len)
+{
+	if (src_offset & 511)
+		return -EINVAL;
+	if (dst_offset & 511)
+		return -EINVAL;
+	if (len & 511)
+		return -EINVAL;
+	src_offset >>= 9;
+	dst_offset >>= 9;
+	len >>= 9;
+
+	if (unlikely(src_offset + len < src_offset) ||
+	    unlikely(src_offset + len > (i_size_read(bdev->bd_inode) >> 9)))
+		return -EINVAL;
+
+	if (unlikely(dst_offset + len < dst_offset) ||
+	    unlikely(dst_offset + len > (i_size_read(bdev->bd_inode) >> 9)))
+		return -EINVAL;
+
+	return blkdev_issue_copy(bdev, src_offset, bdev, dst_offset, len,
+				 GFP_KERNEL);
+}
+
 static int put_ushort(unsigned long arg, unsigned short val)
 {
 	return put_user(val, (unsigned short __user *)arg);
@@ -513,6 +538,31 @@ int blkdev_ioctl(struct block_device *bd
 				BLKDEV_DISCARD_SECURE);
 	case BLKZEROOUT:
 		return blk_ioctl_zeroout(bdev, mode, arg);
+	case BLKCOPY: {
+		uint64_t range[4];
+		int ret;
+
+		range[3] = 0;
+
+		if (copy_to_user((void __user *)(arg + 24), &range[3], 8))
+			return -EFAULT;
+
+		if (!(mode & FMODE_WRITE))
+			return -EBADF;
+
+		if (copy_from_user(range, (void __user *)arg, 24))
+			return -EFAULT;
+
+		ret = blk_ioctl_copy(bdev, range[0], range[1], range[2]);
+		if (!ret) {
+			range[3] = range[2];
+			if (copy_to_user((void __user *)(arg + 24), &range[3], 8))
+				return -EFAULT;
+		}
+
+		return ret;
+	}
+
 	case HDIO_GETGEO:
 		return blkdev_getgeo(bdev, argp);
 	case BLKRAGET:
Index: linux-4.4-rc4/drivers/scsi/scsi.c
===================================================================
--- linux-4.4-rc4.orig/drivers/scsi/scsi.c	2015-12-10 17:04:00.000000000 +0100
+++ linux-4.4-rc4/drivers/scsi/scsi.c	2015-12-10 17:04:30.000000000 +0100
@@ -768,6 +768,62 @@ int scsi_get_vpd_page(struct scsi_device
 EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
 
 /**
+ * scsi_lookup_naa - Lookup NAA descriptor in VPD page 0x83
+ * @sdev: The device to ask
+ *
+ * Copy offloading requires us to know the NAA descriptor for both
+ * source and target device. This descriptor is mandatory in the Device
+ * Identification VPD page. Locate this descriptor in the returned VPD
+ * data so we don't have to do lookups for every copy command.
+ */
+static void scsi_lookup_naa(struct scsi_device *sdev)
+{
+	unsigned char *buf = sdev->vpd_pg83;
+	unsigned int len = sdev->vpd_pg83_len;
+
+	if (buf[1] != 0x83 || get_unaligned_be16(&buf[2]) == 0) {
+		sdev_printk(KERN_ERR, sdev,
+			    "%s: VPD page 0x83 contains no descriptors\n",
+			    __func__);
+		return;
+	}
+
+	buf += 4;
+	len -= 4;
+
+	do {
+		unsigned int desig_len = buf[3] + 4;
+
+		/* Binary code set */
+		if ((buf[0] & 0xf) != 1)
+			goto skip;
+
+		/* Target association */
+		if ((buf[1] >> 4) & 0x3)
+			goto skip;
+
+		/* NAA designator */
+		if ((buf[1] & 0xf) != 0x3)
+			goto skip;
+
+		sdev->naa = buf;
+		sdev->naa_len = desig_len;
+
+		return;
+
+	skip:
+		buf += desig_len;
+		len -= desig_len;
+
+	} while (len > 0);
+
+	sdev_printk(KERN_ERR, sdev,
+		    "%s: VPD page 0x83 NAA descriptor not found\n", __func__);
+
+	return;
+}
+
+/**
  * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
  * @sdev: The device to ask
  *
@@ -851,6 +907,7 @@ retry_pg83:
 		}
 		sdev->vpd_pg83_len = result;
 		sdev->vpd_pg83 = vpd_buf;
+		scsi_lookup_naa(sdev);
 	}
 }
 
Index: linux-4.4-rc4/drivers/scsi/sd.c
===================================================================
--- linux-4.4-rc4.orig/drivers/scsi/sd.c	2015-12-10 17:04:00.000000000 +0100
+++ linux-4.4-rc4/drivers/scsi/sd.c	2015-12-10 17:04:30.000000000 +0100
@@ -101,6 +101,7 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_RBC);
 
 static void sd_config_discard(struct scsi_disk *, unsigned int);
 static void sd_config_write_same(struct scsi_disk *);
+static void sd_config_copy(struct scsi_disk *);
 static int  sd_revalidate_disk(struct gendisk *);
 static void sd_unlock_native_capacity(struct gendisk *disk);
 static int  sd_probe(struct device *);
@@ -479,6 +480,48 @@ max_write_same_blocks_store(struct devic
 }
 static DEVICE_ATTR_RW(max_write_same_blocks);
 
+static ssize_t
+max_copy_blocks_show(struct device *dev, struct device_attribute *attr,
+		     char *buf)
+{
+	struct scsi_disk *sdkp = to_scsi_disk(dev);
+
+	return snprintf(buf, 20, "%u\n", sdkp->max_copy_blocks);
+}
+
+static ssize_t
+max_copy_blocks_store(struct device *dev, struct device_attribute *attr,
+		      const char *buf, size_t count)
+{
+	struct scsi_disk *sdkp = to_scsi_disk(dev);
+	struct scsi_device *sdp = sdkp->device;
+	unsigned long max;
+	int err;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	if (sdp->type != TYPE_DISK)
+		return -EINVAL;
+
+	err = kstrtoul(buf, 10, &max);
+
+	if (err)
+		return err;
+
+	if (max == 0)
+		sdp->no_copy = 1;
+	else if (max <= SD_MAX_COPY_BLOCKS) {
+		sdp->no_copy = 0;
+		sdkp->max_copy_blocks = max;
+	}
+
+	sd_config_copy(sdkp);
+
+	return count;
+}
+static DEVICE_ATTR_RW(max_copy_blocks);
+
 static struct attribute *sd_disk_attrs[] = {
 	&dev_attr_cache_type.attr,
 	&dev_attr_FUA.attr,
@@ -490,6 +533,7 @@ static struct attribute *sd_disk_attrs[]
 	&dev_attr_thin_provisioning.attr,
 	&dev_attr_provisioning_mode.attr,
 	&dev_attr_max_write_same_blocks.attr,
+	&dev_attr_max_copy_blocks.attr,
 	&dev_attr_max_medium_access_timeouts.attr,
 	NULL,
 };
@@ -879,6 +923,116 @@ static int sd_setup_write_same_cmnd(stru
 	return ret;
 }
 
+static void sd_config_copy(struct scsi_disk *sdkp)
+{
+	struct request_queue *q = sdkp->disk->queue;
+	unsigned int logical_block_size = sdkp->device->sector_size;
+
+	if (sdkp->device->no_copy)
+		sdkp->max_copy_blocks = 0;
+
+	/* Segment descriptor 0x02 has a 64k block limit */
+	sdkp->max_copy_blocks = min(sdkp->max_copy_blocks,
+				    (u32)SD_MAX_CSD2_BLOCKS);
+
+	blk_queue_max_copy_sectors(q, sdkp->max_copy_blocks *
+				   (logical_block_size >> 9));
+}
+
+static int sd_setup_copy_cmnd(struct scsi_cmnd *cmd)
+{
+	struct request *rq = cmd->request;
+	struct scsi_device *src_sdp, *dst_sdp;
+	struct gendisk *src_disk;
+	struct request_queue *src_queue, *dst_queue;
+	sector_t src_lba, dst_lba;
+	unsigned int nr_blocks, buf_len, nr_bytes = blk_rq_bytes(rq);
+	int ret;
+	struct bio *bio = rq->bio;
+	struct page *page;
+	unsigned char *buf;
+
+	if (!bio->bi_copy)
+		return BLKPREP_KILL;
+
+	dst_sdp = scsi_disk(rq->rq_disk)->device;
+	dst_queue = rq->rq_disk->queue;
+	src_disk = bio->bi_copy->bic_bdev->bd_disk;
+	src_queue = src_disk->queue;
+	if (!src_queue ||
+	    src_queue->make_request_fn != dst_queue->make_request_fn ||
+	    src_queue->request_fn != dst_queue->request_fn ||
+	    *(struct scsi_driver **)rq->rq_disk->private_data !=
+	    *(struct scsi_driver **)src_disk->private_data)
+		return BLKPREP_KILL;
+	src_sdp = scsi_disk(src_disk)->device;
+
+	if (src_sdp->no_copy || dst_sdp->no_copy)
+		return BLKPREP_KILL;
+
+	if (src_sdp->sector_size != dst_sdp->sector_size)
+		return BLKPREP_KILL;
+
+	dst_lba = blk_rq_pos(rq) >> (ilog2(dst_sdp->sector_size) - 9);
+	src_lba = bio->bi_copy->bic_sector >> (ilog2(src_sdp->sector_size) - 9);
+	nr_blocks = blk_rq_sectors(rq) >> (ilog2(dst_sdp->sector_size) - 9);
+
+	page = alloc_page(GFP_ATOMIC | __GFP_ZERO);
+	if (!page)
+		return BLKPREP_DEFER;
+
+	buf = page_address(page);
+
+	/* Extended Copy (LID1) Parameter List (16 bytes) */
+	buf[0] = 0;				/* LID */
+	buf[1] = 3 << 3;			/* LID usage 11b */
+	put_unaligned_be16(32 + 32, &buf[2]);	/* 32 bytes per E4 desc. */
+	put_unaligned_be32(28, &buf[8]);	/* 28 bytes per B2B desc. */
+	buf += 16;
+
+	/* Source CSCD (32 bytes) */
+	buf[0] = 0xe4;				/* Identification desc. */
+	memcpy(&buf[4], src_sdp->naa, src_sdp->naa_len);
+	buf += 32;
+
+	/* Destination CSCD (32 bytes) */
+	buf[0] = 0xe4;				/* Identification desc. */
+	memcpy(&buf[4], dst_sdp->naa, dst_sdp->naa_len);
+	buf += 32;
+
+	/* Segment descriptor (28 bytes) */
+	buf[0] = 0x02;				/* Block to block desc. */
+	put_unaligned_be16(0x18, &buf[2]);	/* Descriptor length */
+	put_unaligned_be16(0, &buf[4]);		/* Source is desc. 0 */
+	put_unaligned_be16(1, &buf[6]);		/* Dest. is desc. 1 */
+	put_unaligned_be16(nr_blocks, &buf[10]);
+	put_unaligned_be64(src_lba, &buf[12]);
+	put_unaligned_be64(dst_lba, &buf[20]);
+
+	/* CDB */
+	cmd->cmd_len = 16;
+	memset(cmd->cmnd, 0, cmd->cmd_len);
+	cmd->cmnd[0] = EXTENDED_COPY;
+	cmd->cmnd[1] = 0; /* LID1 */
+	buf_len = 16 + 32 + 32 + 28;
+	put_unaligned_be32(buf_len, &cmd->cmnd[10]);
+	rq->timeout = SD_COPY_TIMEOUT;
+
+	rq->completion_data = page;
+	blk_add_request_payload(rq, page, buf_len);
+
+	cmd->transfersize = buf_len;
+	cmd->allowed = 0;	/* don't retry */
+
+	rq->__data_len = buf_len;
+	ret = scsi_init_io(cmd);
+	rq->__data_len = nr_bytes;
+
+	if (ret != BLKPREP_OK)
+		__free_page(page);
+	return ret;
+}
+
 static int sd_setup_flush_cmnd(struct scsi_cmnd *cmd)
 {
 	struct request *rq = cmd->request;
@@ -1141,6 +1295,8 @@ static int sd_init_command(struct scsi_c
 		return sd_setup_discard_cmnd(cmd);
 	else if (rq->cmd_flags & REQ_WRITE_SAME)
 		return sd_setup_write_same_cmnd(cmd);
+	else if (rq->cmd_flags & REQ_COPY)
+		return sd_setup_copy_cmnd(cmd);
 	else if (rq->cmd_flags & REQ_FLUSH)
 		return sd_setup_flush_cmnd(cmd);
 	else
@@ -1151,7 +1307,7 @@ static void sd_uninit_command(struct scs
 {
 	struct request *rq = SCpnt->request;
 
-	if (rq->cmd_flags & REQ_DISCARD)
+	if (rq->cmd_flags & (REQ_DISCARD | REQ_COPY))
 		__free_page(rq->completion_data);
 
 	if (SCpnt->cmnd != rq->cmd) {
@@ -1768,7 +1924,8 @@ static int sd_done(struct scsi_cmnd *SCp
 	unsigned char op = SCpnt->cmnd[0];
 	unsigned char unmap = SCpnt->cmnd[1] & 8;
 
-	if (req->cmd_flags & REQ_DISCARD || req->cmd_flags & REQ_WRITE_SAME) {
+	if (req->cmd_flags & REQ_DISCARD || req->cmd_flags & REQ_WRITE_SAME ||
+	    req->cmd_flags & REQ_COPY) {
 		if (!result) {
 			good_bytes = blk_rq_bytes(req);
 			scsi_set_resid(SCpnt, 0);
@@ -1815,6 +1972,16 @@ static int sd_done(struct scsi_cmnd *SCp
 		/* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
 		if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
 			switch (op) {
+			case EXTENDED_COPY:
+				if ((SCpnt->cmnd[1] & 0x1f) == 0) {
+					sdkp->device->no_copy = 1;
+					sd_config_copy(sdkp);
+
+					good_bytes = 0;
+					req->__data_len = blk_rq_bytes(req);
+					req->cmd_flags |= REQ_QUIET;
+				}
+				break;
 			case UNMAP:
 				sd_config_discard(sdkp, SD_LBP_DISABLE);
 				break;
@@ -2797,6 +2964,105 @@ static void sd_read_write_same(struct sc
 		sdkp->ws10 = 1;
 }
 
+static void sd_read_copy_operations(struct scsi_disk *sdkp,
+				    unsigned char *buffer)
+{
+	struct scsi_device *sdev = sdkp->device;
+	struct scsi_sense_hdr sshdr;
+	unsigned char cdb[16];
+	unsigned int result, len, i;
+	bool b2b_desc = false, id_desc = false;
+
+	if (sdev->naa_len == 0)
+		return;
+
+	/* Verify that the device has 3PC set in INQUIRY response */
+	if (sdev->inquiry_len < 6 || (sdev->inquiry[5] & (1 << 3)) == 0)
+		return;
+
+	/* Receive Copy Operation Parameters */
+	memset(cdb, 0, 16);
+	cdb[0] = RECEIVE_COPY_RESULTS;
+	cdb[1] = 0x3;
+	put_unaligned_be32(SD_BUF_SIZE, &cdb[10]);
+
+	memset(buffer, 0, SD_BUF_SIZE);
+	result = scsi_execute_req(sdev, cdb, DMA_FROM_DEVICE,
+				  buffer, SD_BUF_SIZE, &sshdr,
+				  SD_TIMEOUT, SD_MAX_RETRIES, NULL);
+
+	if (!scsi_status_is_good(result)) {
+		sd_printk(KERN_ERR, sdkp,
+			  "%s: Receive Copy Operating Parameters failed\n",
+			  __func__);
+		return;
+	}
+
+	/* The RCOP response is a minimum of 44 bytes long. First 4
+	 * bytes contain the length of the remaining buffer, i.e. 40+
+	 * bytes. Trailing the defined fields is a list of supported
+	 * descriptors. We need at least 2 descriptors to drive the
+	 * target, hence 42.
+	 */
+	len = get_unaligned_be32(&buffer[0]);
+	if (len < 42) {
+		sd_printk(KERN_ERR, sdkp, "%s: result too short (%u)\n",
+			  __func__, len);
+		return;
+	}
+
+	if ((buffer[4] & 1) == 0) {
+		sd_printk(KERN_ERR, sdkp, "%s: does not support SNLID\n",
+			  __func__);
+		return;
+	}
+
+	if (get_unaligned_be16(&buffer[8]) < 2) {
+		sd_printk(KERN_ERR, sdkp,
+			  "%s: Need 2 or more CSCD descriptors\n", __func__);
+		return;
+	}
+
+	if (get_unaligned_be16(&buffer[10]) < 1) {
+		sd_printk(KERN_ERR, sdkp,
+			  "%s: Need 1 or more segment descriptor\n", __func__);
+		return;
+	}
+
+	if (len - 40 != buffer[43]) {
+		sd_printk(KERN_ERR, sdkp,
+			  "%s: Buffer len and descriptor count mismatch " \
+			  "(%u vs. %u)\n", __func__, len - 40, buffer[43]);
+		return;
+	}
+
+	for (i = 44 ; i < len + 4 ; i++) {
+		if (buffer[i] == 0x02)
+			b2b_desc = true;
+
+		if (buffer[i] == 0xe4)
+			id_desc = true;
+	}
+
+	if (!b2b_desc) {
+		sd_printk(KERN_ERR, sdkp,
+			  "%s: No block 2 block descriptor (0x02)\n",
+			  __func__);
+		return;
+	}
+
+	if (!id_desc) {
+		sd_printk(KERN_ERR, sdkp,
+			  "%s: No identification descriptor (0xE4)\n",
+			  __func__);
+		return;
+	}
+
+	sdkp->max_copy_blocks = get_unaligned_be32(&buffer[16])
+		>> ilog2(sdev->sector_size);
+	sd_config_copy(sdkp);
+}
+
 static int sd_try_extended_inquiry(struct scsi_device *sdp)
 {
 	/* Attempt VPD inquiry if the device blacklist explicitly calls
@@ -2868,6 +3134,7 @@ static int sd_revalidate_disk(struct gen
 		sd_read_cache_type(sdkp, buffer);
 		sd_read_app_tag_own(sdkp, buffer);
 		sd_read_write_same(sdkp, buffer);
+		sd_read_copy_operations(sdkp, buffer);
 	}
 
 	sdkp->first_scan = 0;
Index: linux-4.4-rc4/drivers/scsi/sd.h
===================================================================
--- linux-4.4-rc4.orig/drivers/scsi/sd.h	2015-12-10 17:04:00.000000000 +0100
+++ linux-4.4-rc4/drivers/scsi/sd.h	2015-12-10 17:04:30.000000000 +0100
@@ -19,6 +19,7 @@
  */
 #define SD_FLUSH_TIMEOUT_MULTIPLIER	2
 #define SD_WRITE_SAME_TIMEOUT	(120 * HZ)
+#define SD_COPY_TIMEOUT		(120 * HZ)
 
 /*
  * Number of allowed retries
@@ -48,6 +49,8 @@ enum {
 	SD_MAX_XFER_BLOCKS = 0xffffffff,
 	SD_MAX_WS10_BLOCKS = 0xffff,
 	SD_MAX_WS16_BLOCKS = 0x7fffff,
+	SD_MAX_CSD2_BLOCKS = 0xffff,
+	SD_MAX_COPY_BLOCKS = 0xffffffff,
 };
 
 enum {
@@ -70,6 +73,7 @@ struct scsi_disk {
 	u32		opt_xfer_blocks;
 	u32		max_ws_blocks;
 	u32		max_unmap_blocks;
+	u32		max_copy_blocks;
 	u32		unmap_granularity;
 	u32		unmap_alignment;
 	u32		index;
Index: linux-4.4-rc4/include/linux/bio.h
===================================================================
--- linux-4.4-rc4.orig/include/linux/bio.h	2015-12-10 17:04:00.000000000 +0100
+++ linux-4.4-rc4/include/linux/bio.h	2015-12-10 17:04:30.000000000 +0100
@@ -106,7 +106,7 @@ static inline bool bio_has_data(struct b
 {
 	if (bio &&
 	    bio->bi_iter.bi_size &&
-	    !(bio->bi_rw & REQ_DISCARD))
+	    !(bio->bi_rw & (REQ_DISCARD | REQ_COPY)))
 		return true;
 
 	return false;
@@ -249,8 +249,8 @@ static inline unsigned bio_segments(stru
 	struct bvec_iter iter;
 
 	/*
-	 * We special case discard/write same, because they interpret bi_size
-	 * differently:
+	 * We special case discard/write same/copy, because they
+	 * interpret bi_size differently:
 	 */
 
 	if (bio->bi_rw & REQ_DISCARD)
@@ -259,6 +259,9 @@ static inline unsigned bio_segments(stru
 	if (bio->bi_rw & REQ_WRITE_SAME)
 		return 1;
 
+	if (bio->bi_rw & REQ_COPY)
+		return 1;
+
 	bio_for_each_segment(bv, bio, iter)
 		segs++;
 
Index: linux-4.4-rc4/include/linux/blk_types.h
===================================================================
--- linux-4.4-rc4.orig/include/linux/blk_types.h	2015-12-10 17:04:00.000000000 +0100
+++ linux-4.4-rc4/include/linux/blk_types.h	2015-12-10 17:04:30.000000000 +0100
@@ -39,6 +39,11 @@ struct bvec_iter {
 						   current bvec */
 };
 
+struct bio_copy {
+	struct block_device	*bic_bdev;
+	sector_t		bic_sector;
+};
+
 /*
  * main unit of I/O for the block layer and lower layers (ie drivers and
  * stacking drivers)
@@ -84,6 +89,7 @@ struct bio {
 		struct bio_integrity_payload *bi_integrity; /* data integrity */
 #endif
 	};
+	struct bio_copy		*bi_copy; 	/* TODO, use bi_integrity */
 
 	unsigned short		bi_vcnt;	/* how many bio_vec's */
 
@@ -156,6 +162,7 @@ enum rq_flag_bits {
 	__REQ_DISCARD,		/* request to discard sectors */
 	__REQ_SECURE,		/* secure discard (used with __REQ_DISCARD) */
 	__REQ_WRITE_SAME,	/* write same block many times */
+	__REQ_COPY,		/* copy block range */
 
 	__REQ_NOIDLE,		/* don't anticipate more IO after this one */
 	__REQ_INTEGRITY,	/* I/O includes block integrity payload */
@@ -201,6 +208,7 @@ enum rq_flag_bits {
 #define REQ_PRIO		(1ULL << __REQ_PRIO)
 #define REQ_DISCARD		(1ULL << __REQ_DISCARD)
 #define REQ_WRITE_SAME		(1ULL << __REQ_WRITE_SAME)
+#define REQ_COPY		(1ULL << __REQ_COPY)
 #define REQ_NOIDLE		(1ULL << __REQ_NOIDLE)
 #define REQ_INTEGRITY		(1ULL << __REQ_INTEGRITY)
 
@@ -209,14 +217,14 @@ enum rq_flag_bits {
 #define REQ_COMMON_MASK \
 	(REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | \
 	 REQ_DISCARD | REQ_WRITE_SAME | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | \
-	 REQ_SECURE | REQ_INTEGRITY)
+	 REQ_SECURE | REQ_INTEGRITY | REQ_COPY)
 #define REQ_CLONE_MASK		REQ_COMMON_MASK
 
-#define BIO_NO_ADVANCE_ITER_MASK	(REQ_DISCARD|REQ_WRITE_SAME)
+#define BIO_NO_ADVANCE_ITER_MASK	(REQ_DISCARD|REQ_WRITE_SAME|REQ_COPY)
 
 /* This mask is used for both bio and request merge checking */
 #define REQ_NOMERGE_FLAGS \
-	(REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA | REQ_FLUSH_SEQ)
+	(REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA | REQ_FLUSH_SEQ | REQ_COPY)
 
 #define REQ_RAHEAD		(1ULL << __REQ_RAHEAD)
 #define REQ_THROTTLED		(1ULL << __REQ_THROTTLED)
Index: linux-4.4-rc4/include/linux/blkdev.h
===================================================================
--- linux-4.4-rc4.orig/include/linux/blkdev.h	2015-12-10 17:04:01.000000000 +0100
+++ linux-4.4-rc4/include/linux/blkdev.h	2015-12-10 17:04:30.000000000 +0100
@@ -265,6 +265,7 @@ struct queue_limits {
 	unsigned int		max_discard_sectors;
 	unsigned int		max_hw_discard_sectors;
 	unsigned int		max_write_same_sectors;
+	unsigned int		max_copy_sectors;
 	unsigned int		discard_granularity;
 	unsigned int		discard_alignment;
 
@@ -968,6 +969,8 @@ extern void blk_queue_max_discard_sector
 		unsigned int max_discard_sectors);
 extern void blk_queue_max_write_same_sectors(struct request_queue *q,
 		unsigned int max_write_same_sectors);
+extern void blk_queue_max_copy_sectors(struct request_queue *q,
+		unsigned int max_copy_sectors);
 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
 extern void blk_queue_alignment_offset(struct request_queue *q,
@@ -1137,6 +1140,8 @@ extern int blkdev_issue_discard(struct b
 		sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
 extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
 		sector_t nr_sects, gfp_t gfp_mask, struct page *page);
+extern int blkdev_issue_copy(struct block_device *, sector_t,
+		struct block_device *, sector_t, unsigned int, gfp_t);
 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 		sector_t nr_sects, gfp_t gfp_mask, bool discard);
 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
@@ -1340,6 +1345,16 @@ static inline unsigned int bdev_write_sa
 	return 0;
 }
 
+static inline unsigned int bdev_copy_offload(struct block_device *bdev)
+{
+	struct request_queue *q = bdev_get_queue(bdev);
+
+	if (q)
+		return q->limits.max_copy_sectors;
+
+	return 0;
+}
+
 static inline int queue_dma_alignment(struct request_queue *q)
 {
 	return q ? q->dma_alignment : 511;
Index: linux-4.4-rc4/include/scsi/scsi_device.h
===================================================================
--- linux-4.4-rc4.orig/include/scsi/scsi_device.h	2015-12-10 17:04:00.000000000 +0100
+++ linux-4.4-rc4/include/scsi/scsi_device.h	2015-12-10 17:04:30.000000000 +0100
@@ -120,6 +120,8 @@ struct scsi_device {
 	unsigned char *vpd_pg83;
 	int vpd_pg80_len;
 	unsigned char *vpd_pg80;
+	unsigned char naa_len;
+	unsigned char *naa;
 	unsigned char current_tag;	/* current tag */
 	struct scsi_target      *sdev_target;   /* used only for single_lun */
 
@@ -150,6 +152,7 @@ struct scsi_device {
 	unsigned use_10_for_ms:1; /* first try 10-byte mode sense/select */
 	unsigned no_report_opcodes:1;	/* no REPORT SUPPORTED OPERATION CODES */
 	unsigned no_write_same:1;	/* no WRITE SAME command */
+	unsigned no_copy:1;		/* no copy offload */
 	unsigned use_16_for_rw:1; /* Use read/write(16) over read/write(10) */
 	unsigned skip_ms_page_8:1;	/* do not use MODE SENSE page 0x08 */
 	unsigned skip_ms_page_3f:1;	/* do not use MODE SENSE page 0x3f */
Index: linux-4.4-rc4/include/uapi/linux/fs.h
===================================================================
--- linux-4.4-rc4.orig/include/uapi/linux/fs.h	2015-12-10 17:04:00.000000000 +0100
+++ linux-4.4-rc4/include/uapi/linux/fs.h	2015-12-10 17:04:30.000000000 +0100
@@ -152,6 +152,7 @@ struct inodes_stat_t {
 #define BLKSECDISCARD _IO(0x12,125)
 #define BLKROTATIONAL _IO(0x12,126)
 #define BLKZEROOUT _IO(0x12,127)
+#define BLKCOPY _IO(0x12,128)
 
 #define BMAP_IOCTL 1		/* obsolete - kept for compatibility */
 #define FIBMAP	   _IO(0x00,1)	/* bmap access */
Index: linux-4.4-rc4/block/compat_ioctl.c
===================================================================
--- linux-4.4-rc4.orig/block/compat_ioctl.c	2015-12-10 17:04:00.000000000 +0100
+++ linux-4.4-rc4/block/compat_ioctl.c	2015-12-10 17:04:30.000000000 +0100
@@ -697,6 +697,7 @@ long compat_blkdev_ioctl(struct file *fi
 	 * but we call blkdev_ioctl, which gets the lock for us
 	 */
 	case BLKRRPART:
+	case BLKCOPY:
 		return blkdev_ioctl(bdev, mode, cmd,
 				(unsigned long)compat_ptr(arg));
 	case BLKBSZSET_32:
Index: linux-4.4-rc4/block/bio.c
===================================================================
--- linux-4.4-rc4.orig/block/bio.c	2015-12-10 17:03:59.000000000 +0100
+++ linux-4.4-rc4/block/bio.c	2015-12-10 17:04:30.000000000 +0100
@@ -238,6 +238,8 @@ static void __bio_free(struct bio *bio)
 {
 	bio_disassociate_task(bio);
 
+	kfree(bio->bi_copy);
+
 	if (bio_integrity(bio))
 		bio_integrity_free(bio);
 }

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#1288738 — [PATCH 12/15] dm kcopyd: introduce the function submit_job

We move some code to a function submit_job. It is needed for the next
patch that calls submit_job from another place.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

---
 drivers/md/dm-kcopyd.c |   19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

Index: linux-3.16-rc5/drivers/md/dm-kcopyd.c
===================================================================
--- linux-3.16-rc5.orig/drivers/md/dm-kcopyd.c	2014-07-14 16:45:23.000000000 +0200
+++ linux-3.16-rc5/drivers/md/dm-kcopyd.c	2014-07-14 17:28:36.000000000 +0200
@@ -698,6 +698,17 @@ static void split_job(struct kcopyd_job 
 	}
 }
 
+static void submit_job(struct kcopyd_job *job)
+{
+	if (job->source.count <= SUB_JOB_SIZE)
+		dispatch_job(job);
+	else {
+		mutex_init(&job->lock);
+		job->progress = 0;
+		split_job(job);
+	}
+}
+
 int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
 		   unsigned int num_dests, struct dm_io_region *dests,
 		   unsigned int flags, dm_kcopyd_notify_fn fn, void *context)
@@ -746,13 +757,7 @@ int dm_kcopyd_copy(struct dm_kcopyd_clie
 	job->context = context;
 	job->master_job = job;
 
-	if (job->source.count <= SUB_JOB_SIZE)
-		dispatch_job(job);
-	else {
-		mutex_init(&job->lock);
-		job->progress = 0;
-		split_job(job);
-	}
+	submit_job(job);
 
 	return 0;
 }

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#1288978

>>>>> "Mikulas" == Mikulas Patocka <mpatocka@redhat.com> writes:

Mikulas,

Mikulas> This patch series adds copy offload (the XCOPY command) to the
Mikulas> block layer, SCSI subsystems and device mapper.

Now that the VFS stuff appears to stabilize I agree it's a good time to
revisit all this. I just merged the required VPD patches from Hannes so
those will be in 4.5.

I have a bunch of changes to the SCSI code that I worked on over the
spring/summer based on a feedback from the array vendors after
discussions we started at LSF/MM. Generally speaking, their comments
didn't make things easier, nor prettier :( But your two bio approach is
a requirement to accommodate those needs (token-based copy) so I'll work
on consolidating your changes with mine.

That said, we still need Mike Christie's patches to go in first.

Mike: What's your status? I'm afraid I didn't get a chance to dig very
deep in your series since it coincided with me scrambling to sort out
SCSI for 4.4. Do you think there's a chance we could get your patches in
shape for 4.5? Is there an up-to-date tree I can look at?

-- 
Martin K. Petersen	Oracle Linux Engineering
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#1289145 — Re: [dm-devel] [PATCH 0/15] copy offload patches

On 12/10/2015 04:33 PM, Martin K. Petersen wrote:
>>>>>> "Mikulas" == Mikulas Patocka <mpatocka@redhat.com> writes:
> 
> Mikulas,
> 
> Mikulas> This patch series adds copy offload (the XCOPY command) to the
> Mikulas> block layer, SCSI subsystems and device mapper.
> 
> Now that the VFS stuff appears to stabilize I agree it's a good time to
> revisit all this. I just merged the required VPD patches from Hannes so
> those will be in 4.5.
> 
> I have a bunch of changes to the SCSI code that I worked on over the
> spring/summer based on a feedback from the array vendors after
> discussions we started at LSF/MM. Generally speaking, their comments
> didn't make things easier, nor prettier :( But your two bio approach is
> a requirement to accommodate those needs (token-based copy) so I'll work
> on consolidating your changes with mine.
> 
> That said, we still need Mike Christie's patches to go in first.
> 
> Mike: What's your status? I'm afraid I didn't get a chance to dig very
> deep in your series since it coincided with me scrambling to sort out
> SCSI for 4.4. Do you think there's a chance we could get your patches in
> shape for 4.5? Is there an up-to-date tree I can look at?
> 

It looks like my original mail did not make it due to an attachment.


I just had 2 review comments left:

1. Originally, I had left REQ_FLUSH a flag. Christoph suggested to break
it up into a op and flag:

http://marc.info/?l=linux-scsi&m=144689113106515&w=2

I started this and messed up  Was going to retry next week.


2. Start REQ_OP_READ off at non-zero to try and shake out code that was
not converted.

There are a several places where we assume reads are zero and writes are
1 for things like indexing in arrays (like blktrace's ddir_act or dm
starts), passing into block functions (like nvme_alloc_request's call of
blk_mq_alloc_request), and if/else's. I am not done fixing all of them
and testing.

Ok, 3 comments. One I gave myself:

3. Also, the btrfs patch is really large (1000 lines) because that code
base is so large and there were so many places we passed around rw to
through multiple functions. I wanted to try and break it up, so it would
be easier for those guys to review.


I uploaded a git tree here:

https://github.com/mikechristie/kernel.git

The patches are in the for-next-req-op.

I made this over Jens's for-next branch in his linux-block tree.


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#1289870 — Re: [dm-devel] [PATCH 0/15] copy offload patches

On Thu, Dec 10, 2015 at 11:06:04PM -0600, Mike Christie wrote:
> 
> 2. Start REQ_OP_READ off at non-zero to try and shake out code that was
> not converted.
> 
> There are a several places where we assume reads are zero and writes are
> 1 for things like indexing in arrays (like blktrace's ddir_act or dm
> starts), passing into block functions (like nvme_alloc_request's call of
> blk_mq_alloc_request), and if/else's. I am not done fixing all of them
> and testing.

If this turns out to be too painful we should just skip it.  I though it
would be a nie debugging aid, but we don't need to do it at any cost.
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