Merge tag 'dm-3.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper changes from Mike Snitzer:

 - The most significant change this cycle is request-based DM now
   supports stacking ontop of blk-mq devices.  This blk-mq support
   changes the model request-based DM uses for cloning a request to
   relying on calling blk_get_request() directly from the underlying
   blk-mq device.

   An early consumer of this code is Intel's emerging NVMe hardware;
   thanks to Keith Busch for working on, and pushing for, these changes.

 - A few other small fixes and cleanups across other DM targets.

* tag 'dm-3.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: inherit QUEUE_FLAG_SG_GAPS flags from underlying queues
  dm snapshot: remove unnecessary NULL checks before vfree() calls
  dm mpath: simplify failure path of dm_multipath_init()
  dm thin metadata: remove unused dm_pool_get_data_block_size()
  dm ioctl: fix stale comment above dm_get_inactive_table()
  dm crypt: update url in CONFIG_DM_CRYPT help text
  dm bufio: fix time comparison to use time_after_eq()
  dm: use time_in_range() and time_after()
  dm raid: fix a couple integer overflows
  dm table: train hybrid target type detection to select blk-mq if appropriate
  dm: allocate requests in target when stacking on blk-mq devices
  dm: prepare for allocating blk-mq clone requests in target
  dm: submit stacked requests in irq enabled context
  dm: split request structure out from dm_rq_target_io structure
  dm: remove exports for request-based interfaces without external callers

1 files changed, 66 insertions, 21 deletions

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 7b6b0f0..d376dc8 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -11,6 +11,7 @@
 #include "dm-path-selector.h"
 #include "dm-uevent.h"
 
+#include <linux/blkdev.h>
 #include <linux/ctype.h>
 #include <linux/init.h>
 #include <linux/mempool.h>
@@ -378,18 +379,18 @@ static int __must_push_back(struct multipath *m)
 /*
  * Map cloned requests
  */
-static int multipath_map(struct dm_target *ti, struct request *clone,
-			 union map_info *map_context)
+static int __multipath_map(struct dm_target *ti, struct request *clone,
+			   union map_info *map_context,
+			   struct request *rq, struct request **__clone)
 {
 	struct multipath *m = (struct multipath *) ti->private;
 	int r = DM_MAPIO_REQUEUE;
-	size_t nr_bytes = blk_rq_bytes(clone);
-	unsigned long flags;
+	size_t nr_bytes = clone ? blk_rq_bytes(clone) : blk_rq_bytes(rq);
 	struct pgpath *pgpath;
 	struct block_device *bdev;
 	struct dm_mpath_io *mpio;
 
-	spin_lock_irqsave(&m->lock, flags);
+	spin_lock_irq(&m->lock);
 
 	/* Do we need to select a new pgpath? */
 	if (!m->current_pgpath ||
@@ -411,25 +412,61 @@ static int multipath_map(struct dm_target *ti, struct request *clone,
 		/* ENOMEM, requeue */
 		goto out_unlock;
 
-	bdev = pgpath->path.dev->bdev;
-	clone->q = bdev_get_queue(bdev);
-	clone->rq_disk = bdev->bd_disk;
-	clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
 	mpio = map_context->ptr;
 	mpio->pgpath = pgpath;
 	mpio->nr_bytes = nr_bytes;
+
+	bdev = pgpath->path.dev->bdev;
+
+	spin_unlock_irq(&m->lock);
+
+	if (clone) {
+		/* Old request-based interface: allocated clone is passed in */
+		clone->q = bdev_get_queue(bdev);
+		clone->rq_disk = bdev->bd_disk;
+		clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
+	} else {
+		/* blk-mq request-based interface */
+		*__clone = blk_get_request(bdev_get_queue(bdev),
+					   rq_data_dir(rq), GFP_KERNEL);
+		if (IS_ERR(*__clone))
+			/* ENOMEM, requeue */
+			return r;
+		(*__clone)->bio = (*__clone)->biotail = NULL;
+		(*__clone)->rq_disk = bdev->bd_disk;
+		(*__clone)->cmd_flags |= REQ_FAILFAST_TRANSPORT;
+	}
+
 	if (pgpath->pg->ps.type->start_io)
 		pgpath->pg->ps.type->start_io(&pgpath->pg->ps,
 					      &pgpath->path,
 					      nr_bytes);
-	r = DM_MAPIO_REMAPPED;
+	return DM_MAPIO_REMAPPED;
 
 out_unlock:
-	spin_unlock_irqrestore(&m->lock, flags);
+	spin_unlock_irq(&m->lock);
 
 	return r;
 }
 
+static int multipath_map(struct dm_target *ti, struct request *clone,
+			 union map_info *map_context)
+{
+	return __multipath_map(ti, clone, map_context, NULL, NULL);
+}
+
+static int multipath_clone_and_map(struct dm_target *ti, struct request *rq,
+				   union map_info *map_context,
+				   struct request **clone)
+{
+	return __multipath_map(ti, NULL, map_context, rq, clone);
+}
+
+static void multipath_release_clone(struct request *clone)
+{
+	blk_put_request(clone);
+}
+
 /*
  * If we run out of usable paths, should we queue I/O or error it?
  */
@@ -1666,11 +1703,13 @@ out:
  *---------------------------------------------------------------*/
 static struct target_type multipath_target = {
 	.name = "multipath",
-	.version = {1, 7, 0},
+	.version = {1, 8, 0},
 	.module = THIS_MODULE,
 	.ctr = multipath_ctr,
 	.dtr = multipath_dtr,
 	.map_rq = multipath_map,
+	.clone_and_map_rq = multipath_clone_and_map,
+	.release_clone_rq = multipath_release_clone,
 	.rq_end_io = multipath_end_io,
 	.presuspend = multipath_presuspend,
 	.postsuspend = multipath_postsuspend,
@@ -1694,16 +1733,15 @@ static int __init dm_multipath_init(void)
 	r = dm_register_target(&multipath_target);
 	if (r < 0) {
 		DMERR("register failed %d", r);
-		kmem_cache_destroy(_mpio_cache);
-		return -EINVAL;
+		r = -EINVAL;
+		goto bad_register_target;
 	}
 
 	kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0);
 	if (!kmultipathd) {
 		DMERR("failed to create workqueue kmpathd");
-		dm_unregister_target(&multipath_target);
-		kmem_cache_destroy(_mpio_cache);
-		return -ENOMEM;
+		r = -ENOMEM;
+		goto bad_alloc_kmultipathd;
 	}
 
 	/*
@@ -1716,16 +1754,23 @@ static int __init dm_multipath_init(void)
 						  WQ_MEM_RECLAIM);
 	if (!kmpath_handlerd) {
 		DMERR("failed to create workqueue kmpath_handlerd");
-		destroy_workqueue(kmultipathd);
-		dm_unregister_target(&multipath_target);
-		kmem_cache_destroy(_mpio_cache);
-		return -ENOMEM;
+		r = -ENOMEM;
+		goto bad_alloc_kmpath_handlerd;
 	}
 
 	DMINFO("version %u.%u.%u loaded",
 	       multipath_target.version[0], multipath_target.version[1],
 	       multipath_target.version[2]);
 
+	return 0;
+
+bad_alloc_kmpath_handlerd:
+	destroy_workqueue(kmultipathd);
+bad_alloc_kmultipathd:
+	dm_unregister_target(&multipath_target);
+bad_register_target:
+	kmem_cache_destroy(_mpio_cache);
+
 	return r;
 }