1 files changed, 350 insertions, 256 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index dfb0a551bd88..99642f69bfa7 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -88,10 +88,6 @@ struct clone_info {
 	bool submit_as_polled:1;
 };
 
-#define DM_TARGET_IO_BIO_OFFSET (offsetof(struct dm_target_io, clone))
-#define DM_IO_BIO_OFFSET \
-	(offsetof(struct dm_target_io, clone) + offsetof(struct dm_io, tio))
-
 static inline struct dm_target_io *clone_to_tio(struct bio *clone)
 {
 	return container_of(clone, struct dm_target_io, clone);
@@ -136,14 +132,6 @@ static int get_swap_bios(void)
 	return latch;
 }
 
-/*
- * For mempools pre-allocation at the table loading time.
- */
-struct dm_md_mempools {
-	struct bio_set bs;
-	struct bio_set io_bs;
-};
-
 struct table_device {
 	struct list_head list;
 	refcount_t count;
@@ -423,7 +411,7 @@ static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 static int dm_prepare_ioctl(struct mapped_device *md, int *srcu_idx,
 			    struct block_device **bdev)
 {
-	struct dm_target *tgt;
+	struct dm_target *ti;
 	struct dm_table *map;
 	int r;
 
@@ -434,17 +422,17 @@ retry:
 		return r;
 
 	/* We only support devices that have a single target */
-	if (dm_table_get_num_targets(map) != 1)
+	if (map->num_targets != 1)
 		return r;
 
-	tgt = dm_table_get_target(map, 0);
-	if (!tgt->type->prepare_ioctl)
+	ti = dm_table_get_target(map, 0);
+	if (!ti->type->prepare_ioctl)
 		return r;
 
 	if (dm_suspended_md(md))
 		return -EAGAIN;
 
-	r = tgt->type->prepare_ioctl(tgt, bdev);
+	r = ti->type->prepare_ioctl(ti, bdev);
 	if (r == -ENOTCONN && !fatal_signal_pending(current)) {
 		dm_put_live_table(md, *srcu_idx);
 		msleep(10);
@@ -563,6 +551,10 @@ static void dm_start_io_acct(struct dm_io *io, struct bio *clone)
 		unsigned long flags;
 		/* Can afford locking given DM_TIO_IS_DUPLICATE_BIO */
 		spin_lock_irqsave(&io->lock, flags);
+		if (dm_io_flagged(io, DM_IO_ACCOUNTED)) {
+			spin_unlock_irqrestore(&io->lock, flags);
+			return;
+		}
 		dm_io_set_flag(io, DM_IO_ACCOUNTED);
 		spin_unlock_irqrestore(&io->lock, flags);
 	}
@@ -581,10 +573,7 @@ static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio)
 	struct dm_target_io *tio;
 	struct bio *clone;
 
-	clone = bio_alloc_clone(NULL, bio, GFP_NOIO, &md->io_bs);
-	/* Set default bdev, but target must bio_set_dev() before issuing IO */
-	clone->bi_bdev = md->disk->part0;
-
+	clone = bio_alloc_clone(NULL, bio, GFP_NOIO, &md->mempools->io_bs);
 	tio = clone_to_tio(clone);
 	tio->flags = 0;
 	dm_tio_set_flag(tio, DM_TIO_INSIDE_DM_IO);
@@ -617,6 +606,7 @@ static void free_io(struct dm_io *io)
 static struct bio *alloc_tio(struct clone_info *ci, struct dm_target *ti,
 			     unsigned target_bio_nr, unsigned *len, gfp_t gfp_mask)
 {
+	struct mapped_device *md = ci->io->md;
 	struct dm_target_io *tio;
 	struct bio *clone;
 
@@ -626,13 +616,10 @@ static struct bio *alloc_tio(struct clone_info *ci, struct dm_target *ti,
 		/* alloc_io() already initialized embedded clone */
 		clone = &tio->clone;
 	} else {
-		struct mapped_device *md = ci->io->md;
-
-		clone = bio_alloc_clone(NULL, ci->bio, gfp_mask, &md->bs);
+		clone = bio_alloc_clone(NULL, ci->bio, gfp_mask,
+					&md->mempools->bs);
 		if (!clone)
 			return NULL;
-		/* Set default bdev, but target must bio_set_dev() before issuing IO */
-		clone->bi_bdev = md->disk->part0;
 
 		/* REQ_DM_POLL_LIST shouldn't be inherited */
 		clone->bi_opf &= ~REQ_DM_POLL_LIST;
@@ -648,6 +635,11 @@ static struct bio *alloc_tio(struct clone_info *ci, struct dm_target *ti,
 	tio->len_ptr = len;
 	tio->old_sector = 0;
 
+	/* Set default bdev, but target must bio_set_dev() before issuing IO */
+	clone->bi_bdev = md->disk->part0;
+	if (unlikely(ti->needs_bio_set_dev))
+		bio_set_dev(clone, md->disk->part0);
+
 	if (len) {
 		clone->bi_iter.bi_size = to_bytes(*len);
 		if (bio_integrity(clone))
@@ -718,18 +710,18 @@ static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
 }
 
 static inline struct dm_table *dm_get_live_table_bio(struct mapped_device *md,
-						     int *srcu_idx, struct bio *bio)
+					int *srcu_idx, blk_opf_t bio_opf)
 {
-	if (bio->bi_opf & REQ_NOWAIT)
+	if (bio_opf & REQ_NOWAIT)
 		return dm_get_live_table_fast(md);
 	else
 		return dm_get_live_table(md, srcu_idx);
 }
 
 static inline void dm_put_live_table_bio(struct mapped_device *md, int srcu_idx,
-					 struct bio *bio)
+					 blk_opf_t bio_opf)
 {
-	if (bio->bi_opf & REQ_NOWAIT)
+	if (bio_opf & REQ_NOWAIT)
 		dm_put_live_table_fast(md);
 	else
 		dm_put_live_table(md, srcu_idx);
@@ -886,22 +878,63 @@ static int __noflush_suspending(struct mapped_device *md)
 	return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
 }
 
-static void dm_io_complete(struct dm_io *io)
+static void dm_requeue_add_io(struct dm_io *io, bool first_stage)
 {
-	blk_status_t io_error;
 	struct mapped_device *md = io->md;
+
+	if (first_stage) {
+		struct dm_io *next = md->requeue_list;
+
+		md->requeue_list = io;
+		io->next = next;
+	} else {
+		bio_list_add_head(&md->deferred, io->orig_bio);
+	}
+}
+
+static void dm_kick_requeue(struct mapped_device *md, bool first_stage)
+{
+	if (first_stage)
+		queue_work(md->wq, &md->requeue_work);
+	else
+		queue_work(md->wq, &md->work);
+}
+
+/*
+ * Return true if the dm_io's original bio is requeued.
+ * io->status is updated with error if requeue disallowed.
+ */
+static bool dm_handle_requeue(struct dm_io *io, bool first_stage)
+{
 	struct bio *bio = io->orig_bio;
+	bool handle_requeue = (io->status == BLK_STS_DM_REQUEUE);
+	bool handle_polled_eagain = ((io->status == BLK_STS_AGAIN) &&
+				     (bio->bi_opf & REQ_POLLED));
+	struct mapped_device *md = io->md;
+	bool requeued = false;
 
-	if (io->status == BLK_STS_DM_REQUEUE) {
+	if (handle_requeue || handle_polled_eagain) {
 		unsigned long flags;
+
+		if (bio->bi_opf & REQ_POLLED) {
+			/*
+			 * Upper layer won't help us poll split bio
+			 * (io->orig_bio may only reflect a subset of the
+			 * pre-split original) so clear REQ_POLLED.
+			 */
+			bio_clear_polled(bio);
+		}
+
 		/*
-		 * Target requested pushing back the I/O.
+		 * Target requested pushing back the I/O or
+		 * polled IO hit BLK_STS_AGAIN.
 		 */
 		spin_lock_irqsave(&md->deferred_lock, flags);
-		if (__noflush_suspending(md) &&
-		    !WARN_ON_ONCE(dm_is_zone_write(md, bio))) {
-			/* NOTE early return due to BLK_STS_DM_REQUEUE below */
-			bio_list_add_head(&md->deferred, bio);
+		if ((__noflush_suspending(md) &&
+		     !WARN_ON_ONCE(dm_is_zone_write(md, bio))) ||
+		    handle_polled_eagain || first_stage) {
+			dm_requeue_add_io(io, first_stage);
+			requeued = true;
 		} else {
 			/*
 			 * noflush suspend was interrupted or this is
@@ -912,6 +945,23 @@ static void dm_io_complete(struct dm_io *io)
 		spin_unlock_irqrestore(&md->deferred_lock, flags);
 	}
 
+	if (requeued)
+		dm_kick_requeue(md, first_stage);
+
+	return requeued;
+}
+
+static void __dm_io_complete(struct dm_io *io, bool first_stage)
+{
+	struct bio *bio = io->orig_bio;
+	struct mapped_device *md = io->md;
+	blk_status_t io_error;
+	bool requeued;
+
+	requeued = dm_handle_requeue(io, first_stage);
+	if (requeued && first_stage)
+		return;
+
 	io_error = io->status;
 	if (dm_io_flagged(io, DM_IO_ACCOUNTED))
 		dm_end_io_acct(io);
@@ -931,21 +981,9 @@ static void dm_io_complete(struct dm_io *io)
 	if (unlikely(wq_has_sleeper(&md->wait)))
 		wake_up(&md->wait);
 
-	if (io_error == BLK_STS_DM_REQUEUE || io_error == BLK_STS_AGAIN) {
-		if (bio->bi_opf & REQ_POLLED) {
-			/*
-			 * Upper layer won't help us poll split bio (io->orig_bio
-			 * may only reflect a subset of the pre-split original)
-			 * so clear REQ_POLLED in case of requeue.
-			 */
-			bio_clear_polled(bio);
-			if (io_error == BLK_STS_AGAIN) {
-				/* io_uring doesn't handle BLK_STS_AGAIN (yet) */
-				queue_io(md, bio);
-			}
-		}
+	/* Return early if the original bio was requeued */
+	if (requeued)
 		return;
-	}
 
 	if (bio_is_flush_with_data(bio)) {
 		/*
@@ -962,6 +1000,58 @@ static void dm_io_complete(struct dm_io *io)
 	}
 }
 
+static void dm_wq_requeue_work(struct work_struct *work)
+{
+	struct mapped_device *md = container_of(work, struct mapped_device,
+						requeue_work);
+	unsigned long flags;
+	struct dm_io *io;
+
+	/* reuse deferred lock to simplify dm_handle_requeue */
+	spin_lock_irqsave(&md->deferred_lock, flags);
+	io = md->requeue_list;
+	md->requeue_list = NULL;
+	spin_unlock_irqrestore(&md->deferred_lock, flags);
+
+	while (io) {
+		struct dm_io *next = io->next;
+
+		dm_io_rewind(io, &md->queue->bio_split);
+
+		io->next = NULL;
+		__dm_io_complete(io, false);
+		io = next;
+	}
+}
+
+/*
+ * Two staged requeue:
+ *
+ * 1) io->orig_bio points to the real original bio, and the part mapped to
+ *    this io must be requeued, instead of other parts of the original bio.
+ *
+ * 2) io->orig_bio points to new cloned bio which matches the requeued dm_io.
+ */
+static void dm_io_complete(struct dm_io *io)
+{
+	bool first_requeue;
+
+	/*
+	 * Only dm_io that has been split needs two stage requeue, otherwise
+	 * we may run into long bio clone chain during suspend and OOM could
+	 * be triggered.
+	 *
+	 * Also flush data dm_io won't be marked as DM_IO_WAS_SPLIT, so they
+	 * also aren't handled via the first stage requeue.
+	 */
+	if (dm_io_flagged(io, DM_IO_WAS_SPLIT))
+		first_requeue = true;
+	else
+		first_requeue = false;
+
+	__dm_io_complete(io, first_requeue);
+}
+
 /*
  * Decrements the number of outstanding ios that a bio has been
  * cloned into, completing the original io if necc.
@@ -1023,23 +1113,19 @@ static void clone_endio(struct bio *bio)
 	struct dm_io *io = tio->io;
 	struct mapped_device *md = io->md;
 
-	if (likely(bio->bi_bdev != md->disk->part0)) {
-		struct request_queue *q = bdev_get_queue(bio->bi_bdev);
-
-		if (unlikely(error == BLK_STS_TARGET)) {
-			if (bio_op(bio) == REQ_OP_DISCARD &&
-			    !bdev_max_discard_sectors(bio->bi_bdev))
-				disable_discard(md);
-			else if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
-				 !q->limits.max_write_zeroes_sectors)
-				disable_write_zeroes(md);
-		}
-
-		if (static_branch_unlikely(&zoned_enabled) &&
-		    unlikely(blk_queue_is_zoned(q)))
-			dm_zone_endio(io, bio);
+	if (unlikely(error == BLK_STS_TARGET)) {
+		if (bio_op(bio) == REQ_OP_DISCARD &&
+		    !bdev_max_discard_sectors(bio->bi_bdev))
+			disable_discard(md);
+		else if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
+			 !bdev_write_zeroes_sectors(bio->bi_bdev))
+			disable_write_zeroes(md);
 	}
 
+	if (static_branch_unlikely(&zoned_enabled) &&
+	    unlikely(bdev_is_zoned(bio->bi_bdev)))
+		dm_zone_endio(io, bio);
+
 	if (endio) {
 		int r = endio(ti, bio, &error);
 		switch (r) {
@@ -1090,23 +1176,18 @@ static sector_t max_io_len(struct dm_target *ti, sector_t sector)
 {
 	sector_t target_offset = dm_target_offset(ti, sector);
 	sector_t len = max_io_len_target_boundary(ti, target_offset);
-	sector_t max_len;
 
 	/*
 	 * Does the target need to split IO even further?
 	 * - varied (per target) IO splitting is a tenet of DM; this
 	 *   explains why stacked chunk_sectors based splitting via
-	 *   blk_max_size_offset() isn't possible here. So pass in
-	 *   ti->max_io_len to override stacked chunk_sectors.
+	 *   blk_queue_split() isn't possible here.
 	 */
-	if (ti->max_io_len) {
-		max_len = blk_max_size_offset(ti->table->md->queue,
-					      target_offset, ti->max_io_len);
-		if (len > max_len)
-			len = max_len;
-	}
-
-	return len;
+	if (!ti->max_io_len)
+		return len;
+	return min_t(sector_t, len,
+		min(queue_max_sectors(ti->table->md->queue),
+		    blk_chunk_sectors_left(target_offset, ti->max_io_len)));
 }
 
 int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
@@ -1249,6 +1330,7 @@ out:
 void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
 {
 	struct dm_target_io *tio = clone_to_tio(bio);
+	struct dm_io *io = tio->io;
 	unsigned bio_sectors = bio_sectors(bio);
 
 	BUG_ON(dm_tio_flagged(tio, DM_TIO_IS_DUPLICATE_BIO));
@@ -1264,8 +1346,9 @@ void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
 	 * __split_and_process_bio() may have already saved mapped part
 	 * for accounting but it is being reduced so update accordingly.
 	 */
-	dm_io_set_flag(tio->io, DM_IO_WAS_SPLIT);
-	tio->io->sectors = n_sectors;
+	dm_io_set_flag(io, DM_IO_WAS_SPLIT);
+	io->sectors = n_sectors;
+	io->sector_offset = bio_sectors(io->orig_bio);
 }
 EXPORT_SYMBOL_GPL(dm_accept_partial_bio);
 
@@ -1388,17 +1471,7 @@ static void setup_split_accounting(struct clone_info *ci, unsigned len)
 		 */
 		dm_io_set_flag(io, DM_IO_WAS_SPLIT);
 		io->sectors = len;
-	}
-
-	if (static_branch_unlikely(&stats_enabled) &&
-	    unlikely(dm_stats_used(&io->md->stats))) {
-		/*
-		 * Save bi_sector in terms of its offset from end of
-		 * original bio, only needed for DM-stats' benefit.
-		 * - saved regardless of whether split needed so that
-		 *   dm_accept_partial_bio() doesn't need to.
-		 */
-		io->sector_offset = bio_end_sector(ci->bio) - ci->sector;
+		io->sector_offset = bio_sectors(ci->bio);
 	}
 }
 
@@ -1432,11 +1505,11 @@ static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci,
 }
 
 static int __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
-				  unsigned num_bios, unsigned *len)
+				 unsigned int num_bios, unsigned *len)
 {
 	struct bio_list blist = BIO_EMPTY_LIST;
 	struct bio *clone;
-	int ret = 0;
+	unsigned int ret = 0;
 
 	switch (num_bios) {
 	case 0:
@@ -1464,8 +1537,7 @@ static int __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
 
 static void __send_empty_flush(struct clone_info *ci)
 {
-	unsigned target_nr = 0;
-	struct dm_target *ti;
+	struct dm_table *t = ci->map;
 	struct bio flush_bio;
 
 	/*
@@ -1480,8 +1552,9 @@ static void __send_empty_flush(struct clone_info *ci)
 	ci->sector_count = 0;
 	ci->io->tio.clone.bi_iter.bi_size = 0;
 
-	while ((ti = dm_table_get_target(ci->map, target_nr++))) {
-		int bios;
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		unsigned int bios;
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		atomic_add(ti->num_flush_bios, &ci->io->io_count);
 		bios = __send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);
@@ -1501,7 +1574,7 @@ static void __send_changing_extent_only(struct clone_info *ci, struct dm_target
 					unsigned num_bios)
 {
 	unsigned len;
-	int bios;
+	unsigned int bios;
 
 	len = min_t(sector_t, ci->sector_count,
 		    max_io_len_target_boundary(ti, dm_target_offset(ti, ci->sector)));
@@ -1520,7 +1593,7 @@ static void __send_changing_extent_only(struct clone_info *ci, struct dm_target
 
 static bool is_abnormal_io(struct bio *bio)
 {
-	unsigned int op = bio_op(bio);
+	enum req_op op = bio_op(bio);
 
 	if (op != REQ_OP_READ && op != REQ_OP_WRITE && op != REQ_OP_FLUSH) {
 		switch (op) {
@@ -1551,6 +1624,8 @@ static blk_status_t __process_abnormal_io(struct clone_info *ci,
 	case REQ_OP_WRITE_ZEROES:
 		num_bios = ti->num_write_zeroes_bios;
 		break;
+	default:
+		break;
 	}
 
 	/*
@@ -1620,14 +1695,19 @@ static blk_status_t __split_and_process_bio(struct clone_info *ci)
 	ti = dm_table_find_target(ci->map, ci->sector);
 	if (unlikely(!ti))
 		return BLK_STS_IOERR;
-	else if (unlikely(ci->is_abnormal_io))
+
+	if (unlikely((ci->bio->bi_opf & REQ_NOWAIT) != 0) &&
+	    unlikely(!dm_target_supports_nowait(ti->type)))
+		return BLK_STS_NOTSUPP;
+
+	if (unlikely(ci->is_abnormal_io))
 		return __process_abnormal_io(ci, ti);
 
 	/*
 	 * Only support bio polling for normal IO, and the target io is
 	 * exactly inside the dm_io instance (verified in dm_poll_dm_io)
 	 */
-	ci->submit_as_polled = ci->bio->bi_opf & REQ_POLLED;
+	ci->submit_as_polled = !!(ci->bio->bi_opf & REQ_POLLED);
 
 	len = min_t(sector_t, max_io_len(ti, ci->sector), ci->sector_count);
 	setup_split_accounting(ci, len);
@@ -1722,8 +1802,9 @@ static void dm_submit_bio(struct bio *bio)
 	struct mapped_device *md = bio->bi_bdev->bd_disk->private_data;
 	int srcu_idx;
 	struct dm_table *map;
+	blk_opf_t bio_opf = bio->bi_opf;
 
-	map = dm_get_live_table_bio(md, &srcu_idx, bio);
+	map = dm_get_live_table_bio(md, &srcu_idx, bio_opf);
 
 	/* If suspended, or map not yet available, queue this IO for later */
 	if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) ||
@@ -1739,7 +1820,7 @@ static void dm_submit_bio(struct bio *bio)
 
 	dm_split_and_process_bio(md, map, bio);
 out:
-	dm_put_live_table_bio(md, srcu_idx, bio);
+	dm_put_live_table_bio(md, srcu_idx, bio_opf);
 }
 
 static bool dm_poll_dm_io(struct dm_io *io, struct io_comp_batch *iob,
@@ -1876,8 +1957,7 @@ static void cleanup_mapped_device(struct mapped_device *md)
 {
 	if (md->wq)
 		destroy_workqueue(md->wq);
-	bioset_exit(&md->bs);
-	bioset_exit(&md->io_bs);
+	dm_free_md_mempools(md->mempools);
 
 	if (md->dax_dev) {
 		dax_remove_host(md->disk);
@@ -1896,7 +1976,7 @@ static void cleanup_mapped_device(struct mapped_device *md)
 			del_gendisk(md->disk);
 		}
 		dm_queue_destroy_crypto_profile(md->queue);
-		blk_cleanup_disk(md->disk);
+		put_disk(md->disk);
 	}
 
 	if (md->pending_io) {
@@ -1971,9 +2051,11 @@ static struct mapped_device *alloc_dev(int minor)
 
 	init_waitqueue_head(&md->wait);
 	INIT_WORK(&md->work, dm_wq_work);
+	INIT_WORK(&md->requeue_work, dm_wq_requeue_work);
 	init_waitqueue_head(&md->eventq);
 	init_completion(&md->kobj_holder.completion);
 
+	md->requeue_list = NULL;
 	md->swap_bios = get_swap_bios();
 	sema_init(&md->swap_bios_semaphore, md->swap_bios);
 	mutex_init(&md->swap_bios_lock);
@@ -2049,48 +2131,6 @@ static void free_dev(struct mapped_device *md)
 	kvfree(md);
 }
 
-static int __bind_mempools(struct mapped_device *md, struct dm_table *t)
-{
-	struct dm_md_mempools *p = dm_table_get_md_mempools(t);
-	int ret = 0;
-
-	if (dm_table_bio_based(t)) {
-		/*
-		 * The md may already have mempools that need changing.
-		 * If so, reload bioset because front_pad may have changed
-		 * because a different table was loaded.
-		 */
-		bioset_exit(&md->bs);
-		bioset_exit(&md->io_bs);
-
-	} else if (bioset_initialized(&md->bs)) {
-		/*
-		 * There's no need to reload with request-based dm
-		 * because the size of front_pad doesn't change.
-		 * Note for future: If you are to reload bioset,
-		 * prep-ed requests in the queue may refer
-		 * to bio from the old bioset, so you must walk
-		 * through the queue to unprep.
-		 */
-		goto out;
-	}
-
-	BUG_ON(!p ||
-	       bioset_initialized(&md->bs) ||
-	       bioset_initialized(&md->io_bs));
-
-	ret = bioset_init_from_src(&md->bs, &p->bs);
-	if (ret)
-		goto out;
-	ret = bioset_init_from_src(&md->io_bs, &p->io_bs);
-	if (ret)
-		bioset_exit(&md->bs);
-out:
-	/* mempool bind completed, no longer need any mempools in the table */
-	dm_table_free_md_mempools(t);
-	return ret;
-}
-
 /*
  * Bind a table to the device.
  */
@@ -2144,12 +2184,28 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
 		 * immutable singletons - used to optimize dm_mq_queue_rq.
 		 */
 		md->immutable_target = dm_table_get_immutable_target(t);
-	}
 
-	ret = __bind_mempools(md, t);
-	if (ret) {
-		old_map = ERR_PTR(ret);
-		goto out;
+		/*
+		 * There is no need to reload with request-based dm because the
+		 * size of front_pad doesn't change.
+		 *
+		 * Note for future: If you are to reload bioset, prep-ed
+		 * requests in the queue may refer to bio from the old bioset,
+		 * so you must walk through the queue to unprep.
+		 */
+		if (!md->mempools) {
+			md->mempools = t->mempools;
+			t->mempools = NULL;
+		}
+	} else {
+		/*
+		 * The md may already have mempools that need changing.
+		 * If so, reload bioset because front_pad may have changed
+		 * because a different table was loaded.
+		 */
+		dm_free_md_mempools(md->mempools);
+		md->mempools = t->mempools;
+		t->mempools = NULL;
 	}
 
 	ret = dm_table_set_restrictions(t, md->queue, limits);
@@ -3006,54 +3062,6 @@ int dm_noflush_suspending(struct dm_target *ti)
 }
 EXPORT_SYMBOL_GPL(dm_noflush_suspending);
 
-struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, enum dm_queue_mode type,
-					    unsigned per_io_data_size, unsigned min_pool_size,
-					    bool integrity, bool poll)
-{
-	struct dm_md_mempools *pools = kzalloc_node(sizeof(*pools), GFP_KERNEL, md->numa_node_id);
-	unsigned int pool_size = 0;
-	unsigned int front_pad, io_front_pad;
-	int ret;
-
-	if (!pools)
-		return NULL;
-
-	switch (type) {
-	case DM_TYPE_BIO_BASED:
-	case DM_TYPE_DAX_BIO_BASED:
-		pool_size = max(dm_get_reserved_bio_based_ios(), min_pool_size);
-		front_pad = roundup(per_io_data_size, __alignof__(struct dm_target_io)) + DM_TARGET_IO_BIO_OFFSET;
-		io_front_pad = roundup(per_io_data_size,  __alignof__(struct dm_io)) + DM_IO_BIO_OFFSET;
-		ret = bioset_init(&pools->io_bs, pool_size, io_front_pad, poll ? BIOSET_PERCPU_CACHE : 0);
-		if (ret)
-			goto out;
-		if (integrity && bioset_integrity_create(&pools->io_bs, pool_size))
-			goto out;
-		break;
-	case DM_TYPE_REQUEST_BASED:
-		pool_size = max(dm_get_reserved_rq_based_ios(), min_pool_size);
-		front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
-		/* per_io_data_size is used for blk-mq pdu at queue allocation */
-		break;
-	default:
-		BUG();
-	}
-
-	ret = bioset_init(&pools->bs, pool_size, front_pad, 0);
-	if (ret)
-		goto out;
-
-	if (integrity && bioset_integrity_create(&pools->bs, pool_size))
-		goto out;
-
-	return pools;
-
-out:
-	dm_free_md_mempools(pools);
-
-	return NULL;
-}
-
 void dm_free_md_mempools(struct dm_md_mempools *pools)
 {
 	if (!pools)
@@ -3069,11 +3077,14 @@ struct dm_pr {
 	u64	old_key;
 	u64	new_key;
 	u32	flags;
+	bool	abort;
 	bool	fail_early;
+	int	ret;
+	enum pr_type type;
 };
 
 static int dm_call_pr(struct block_device *bdev, iterate_devices_callout_fn fn,
-		      void *data)
+		      struct dm_pr *pr)
 {
 	struct mapped_device *md = bdev->bd_disk->private_data;
 	struct dm_table *table;
@@ -3085,15 +3096,21 @@ static int dm_call_pr(struct block_device *bdev, iterate_devices_callout_fn fn,
 		goto out;
 
 	/* We only support devices that have a single target */
-	if (dm_table_get_num_targets(table) != 1)
+	if (table->num_targets != 1)
 		goto out;
 	ti = dm_table_get_target(table, 0);
 
+	if (dm_suspended_md(md)) {
+		ret = -EAGAIN;
+		goto out;
+	}
+
 	ret = -EINVAL;
 	if (!ti->type->iterate_devices)
 		goto out;
 
-	ret = ti->type->iterate_devices(ti, fn, data);
+	ti->type->iterate_devices(ti, fn, pr);
+	ret = 0;
 out:
 	dm_put_live_table(md, srcu_idx);
 	return ret;
@@ -3107,10 +3124,24 @@ static int __dm_pr_register(struct dm_target *ti, struct dm_dev *dev,
 {
 	struct dm_pr *pr = data;
 	const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
+	int ret;
+
+	if (!ops || !ops->pr_register) {
+		pr->ret = -EOPNOTSUPP;
+		return -1;
+	}
+
+	ret = ops->pr_register(dev->bdev, pr->old_key, pr->new_key, pr->flags);
+	if (!ret)
+		return 0;
+
+	if (!pr->ret)
+		pr->ret = ret;
+
+	if (pr->fail_early)
+		return -1;
 
-	if (!ops || !ops->pr_register)
-		return -EOPNOTSUPP;
-	return ops->pr_register(dev->bdev, pr->old_key, pr->new_key, pr->flags);
+	return 0;
 }
 
 static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
@@ -3121,82 +3152,145 @@ static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
 		.new_key	= new_key,
 		.flags		= flags,
 		.fail_early	= true,
+		.ret		= 0,
 	};
 	int ret;
 
 	ret = dm_call_pr(bdev, __dm_pr_register, &pr);
-	if (ret && new_key) {
-		/* unregister all paths if we failed to register any path */
-		pr.old_key = new_key;
-		pr.new_key = 0;
-		pr.flags = 0;
-		pr.fail_early = false;
-		dm_call_pr(bdev, __dm_pr_register, &pr);
+	if (ret) {
+		/* Didn't even get to register a path */
+		return ret;
 	}
 
+	if (!pr.ret)
+		return 0;
+	ret = pr.ret;
+
+	if (!new_key)
+		return ret;
+
+	/* unregister all paths if we failed to register any path */
+	pr.old_key = new_key;
+	pr.new_key = 0;
+	pr.flags = 0;
+	pr.fail_early = false;
+	(void) dm_call_pr(bdev, __dm_pr_register, &pr);
 	return ret;
 }
 
+
+static int __dm_pr_reserve(struct dm_target *ti, struct dm_dev *dev,
+			   sector_t start, sector_t len, void *data)
+{
+	struct dm_pr *pr = data;
+	const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
+
+	if (!ops || !ops->pr_reserve) {
+		pr->ret = -EOPNOTSUPP;
+		return -1;
+	}
+
+	pr->ret = ops->pr_reserve(dev->bdev, pr->old_key, pr->type, pr->flags);
+	if (!pr->ret)
+		return -1;
+
+	return 0;
+}
+
 static int dm_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type,
 			 u32 flags)
 {
-	struct mapped_device *md = bdev->bd_disk->private_data;
-	const struct pr_ops *ops;
-	int r, srcu_idx;
+	struct dm_pr pr = {
+		.old_key	= key,
+		.flags		= flags,
+		.type		= type,
+		.fail_early	= false,
+		.ret		= 0,
+	};
+	int ret;
 
-	r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
-	if (r < 0)
-		goto out;
+	ret = dm_call_pr(bdev, __dm_pr_reserve, &pr);
+	if (ret)
+		return ret;
 
-	ops = bdev->bd_disk->fops->pr_ops;
-	if (ops && ops->pr_reserve)
-		r = ops->pr_reserve(bdev, key, type, flags);
-	else
-		r = -EOPNOTSUPP;
-out:
-	dm_unprepare_ioctl(md, srcu_idx);
-	return r;
+	return pr.ret;
+}
+
+/*
+ * If there is a non-All Registrants type of reservation, the release must be
+ * sent down the holding path. For the cases where there is no reservation or
+ * the path is not the holder the device will also return success, so we must
+ * try each path to make sure we got the correct path.
+ */
+static int __dm_pr_release(struct dm_target *ti, struct dm_dev *dev,
+			   sector_t start, sector_t len, void *data)
+{
+	struct dm_pr *pr = data;
+	const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
+
+	if (!ops || !ops->pr_release) {
+		pr->ret = -EOPNOTSUPP;
+		return -1;
+	}
+
+	pr->ret = ops->pr_release(dev->bdev, pr->old_key, pr->type);
+	if (pr->ret)
+		return -1;
+
+	return 0;
 }
 
 static int dm_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
 {
-	struct mapped_device *md = bdev->bd_disk->private_data;
-	const struct pr_ops *ops;
-	int r, srcu_idx;
+	struct dm_pr pr = {
+		.old_key	= key,
+		.type		= type,
+		.fail_early	= false,
+	};
+	int ret;
 
-	r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
-	if (r < 0)
-		goto out;
+	ret = dm_call_pr(bdev, __dm_pr_release, &pr);
+	if (ret)
+		return ret;
 
-	ops = bdev->bd_disk->fops->pr_ops;
-	if (ops && ops->pr_release)
-		r = ops->pr_release(bdev, key, type);
-	else
-		r = -EOPNOTSUPP;
-out:
-	dm_unprepare_ioctl(md, srcu_idx);
-	return r;
+	return pr.ret;
+}
+
+static int __dm_pr_preempt(struct dm_target *ti, struct dm_dev *dev,
+			   sector_t start, sector_t len, void *data)
+{
+	struct dm_pr *pr = data;
+	const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
+
+	if (!ops || !ops->pr_preempt) {
+		pr->ret = -EOPNOTSUPP;
+		return -1;
+	}
+
+	pr->ret = ops->pr_preempt(dev->bdev, pr->old_key, pr->new_key, pr->type,
+				  pr->abort);
+	if (!pr->ret)
+		return -1;
+
+	return 0;
 }
 
 static int dm_pr_preempt(struct block_device *bdev, u64 old_key, u64 new_key,
 			 enum pr_type type, bool abort)
 {
-	struct mapped_device *md = bdev->bd_disk->private_data;
-	const struct pr_ops *ops;
-	int r, srcu_idx;
+	struct dm_pr pr = {
+		.new_key	= new_key,
+		.old_key	= old_key,
+		.type		= type,
+		.fail_early	= false,
+	};
+	int ret;
 
-	r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
-	if (r < 0)
-		goto out;
+	ret = dm_call_pr(bdev, __dm_pr_preempt, &pr);
+	if (ret)
+		return ret;
 
-	ops = bdev->bd_disk->fops->pr_ops;
-	if (ops && ops->pr_preempt)
-		r = ops->pr_preempt(bdev, old_key, new_key, type, abort);
-	else
-		r = -EOPNOTSUPP;
-out:
-	dm_unprepare_ioctl(md, srcu_idx);
-	return r;
+	return pr.ret;
 }
 
 static int dm_pr_clear(struct block_device *bdev, u64 key)