From e810cb78bc4b4febeac451a0d823ca68622cd86b Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Wed, 8 Jun 2022 08:34:09 +0200
Subject: dm: refactor dm_md_mempool allocation

The current split between dm_table_alloc_md_mempools and
dm_alloc_md_mempools is rather arbitrary, so merge the two
into one easy to follow function.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 drivers/md/dm.c | 52 ----------------------------------------------------
 1 file changed, 52 deletions(-)

(limited to 'drivers/md/dm.c')

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 8872f9c63688..84929bd137d0 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);
@@ -2978,54 +2974,6 @@ 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)
-- 
cgit v1.2.3


From 444fe04f7a5a7991daa1a8fc3680670ac87fc2ce Mon Sep 17 00:00:00 2001
From: Ming Lei <ming.lei@redhat.com>
Date: Fri, 24 Jun 2022 22:12:53 +0800
Subject: dm: improve BLK_STS_DM_REQUEUE and BLK_STS_AGAIN handling

If either BLK_STS_DM_REQUEUE or BLK_STS_AGAIN is returned for POLLED
io, we requeue the original bio into deferred list and kick md->wq to
re-submit it to block layer.

Improve the handling in the following way:

1) Factor out dm_handle_requeue() for handling dm_io requeue.

2) Unify handling for BLK_STS_DM_REQUEUE and BLK_STS_AGAIN: clear
   REQ_POLLED for BLK_STS_DM_REQUEUE too, for the sake of simplicity,
   given BLK_STS_DM_REQUEUE is very unusual.

3) Queue md->wq explicitly in dm_handle_requeue(), so requeue handling
   becomes more robust.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 drivers/md/dm.c | 70 ++++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 45 insertions(+), 25 deletions(-)

(limited to 'drivers/md/dm.c')

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 84929bd137d0..c987f9ad24a4 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -880,22 +880,41 @@ 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)
+/*
+ * 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)
 {
-	blk_status_t io_error;
-	struct mapped_device *md = io->md;
 	struct bio *bio = io->split_bio ? io->split_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 */
+		if ((__noflush_suspending(md) &&
+		     !WARN_ON_ONCE(dm_is_zone_write(md, bio))) ||
+		    handle_polled_eagain) {
 			bio_list_add_head(&md->deferred, bio);
+			requeued = true;
 		} else {
 			/*
 			 * noflush suspend was interrupted or this is
@@ -906,6 +925,21 @@ static void dm_io_complete(struct dm_io *io)
 		spin_unlock_irqrestore(&md->deferred_lock, flags);
 	}
 
+	if (requeued)
+		queue_work(md->wq, &md->work);
+
+	return requeued;
+}
+
+static void dm_io_complete(struct dm_io *io)
+{
+	struct bio *bio = io->split_bio ? io->split_bio : io->orig_bio;
+	struct mapped_device *md = io->md;
+	blk_status_t io_error;
+	bool requeued;
+
+	requeued = dm_handle_requeue(io);
+
 	io_error = io->status;
 	if (dm_io_flagged(io, DM_IO_ACCOUNTED))
 		dm_end_io_acct(io);
@@ -925,23 +959,9 @@ 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;
-			}
-		}
-		if (io_error == BLK_STS_DM_REQUEUE)
-			return;
-	}
+	/* Return early if the original bio was requeued */
+	if (requeued)
+		return;
 
 	if (bio_is_flush_with_data(bio)) {
 		/*
-- 
cgit v1.2.3


From 8b211aaccb915bbf4f4a68f1910c4de701df393b Mon Sep 17 00:00:00 2001
From: Ming Lei <ming.lei@redhat.com>
Date: Fri, 24 Jun 2022 22:12:55 +0800
Subject: dm: add two stage requeue mechanism

Commit 61b6e2e5321d ("dm: fix BLK_STS_DM_REQUEUE handling when dm_io
represents split bio") reverted DM core's bio splitting back to using
bio_split()+bio_chain() because it was found that otherwise DM's
BLK_STS_DM_REQUEUE would trigger a live-lock waiting for bio
completion that would never occur.

Restore using bio_trim()+bio_inc_remaining(), like was done in commit
7dd76d1feec7 ("dm: improve bio splitting and associated IO
accounting"), but this time with proper handling for the above
scenario that is covered in more detail in the commit header for
61b6e2e5321d.

Solve this issue by adding a two staged dm_io requeue mechanism that
uses the new dm_bio_rewind() via dm_io_rewind():

1) requeue the dm_io into the requeue_list added to struct
   mapped_device, and schedule it via new added requeue work. This
   workqueue just clones the dm_io->orig_bio (which DM saves and
   ensures its end sector isn't modified). dm_io_rewind() uses the
   sectors and sectors_offset members of the dm_io that are recorded
   relative to the end of orig_bio: dm_bio_rewind()+bio_trim() are
   then used to make that cloned bio reflect the subset of the
   original bio that is represented by the dm_io that is being
   requeued.

2) the 2nd stage requeue is same with original requeue, but
   io->orig_bio points to new cloned bio (which matches the requeued
   dm_io as described above).

This allows DM core to shift the need for bio cloning from bio-split
time (during IO submission) to the less likely BLK_STS_DM_REQUEUE
handling (after IO completes with that error).

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 drivers/md/dm-core.h      |  15 ++++--
 drivers/md/dm-io-rewind.c |  25 +++++++++-
 drivers/md/dm.c           | 121 +++++++++++++++++++++++++++++++++++-----------
 3 files changed, 130 insertions(+), 31 deletions(-)

(limited to 'drivers/md/dm.c')

diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index 688aeba248d7..8ef780a6baae 100644
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -22,6 +22,8 @@
 
 #define DM_RESERVED_MAX_IOS		1024
 
+struct dm_io;
+
 struct dm_kobject_holder {
 	struct kobject kobj;
 	struct completion completion;
@@ -91,6 +93,14 @@ struct mapped_device {
 	spinlock_t deferred_lock;
 	struct bio_list deferred;
 
+	/*
+	 * requeue work context is needed for cloning one new bio
+	 * to represent the dm_io to be requeued, since each
+	 * dm_io may point to the original bio from FS.
+	 */
+	struct work_struct requeue_work;
+	struct dm_io *requeue_list;
+
 	void *interface_ptr;
 
 	/*
@@ -275,7 +285,6 @@ struct dm_io {
 	atomic_t io_count;
 	struct mapped_device *md;
 
-	struct bio *split_bio;
 	/* The three fields represent mapped part of original bio */
 	struct bio *orig_bio;
 	unsigned int sector_offset; /* offset to end of orig_bio */
@@ -303,6 +312,8 @@ static inline void dm_io_set_flag(struct dm_io *io, unsigned int bit)
 	io->flags |= (1U << bit);
 }
 
+void dm_io_rewind(struct dm_io *io, struct bio_set *bs);
+
 static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
 {
 	return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
@@ -319,6 +330,4 @@ extern atomic_t dm_global_event_nr;
 extern wait_queue_head_t dm_global_eventq;
 void dm_issue_global_event(void);
 
-void dm_bio_rewind(struct bio *bio, unsigned bytes);
-
 #endif
diff --git a/drivers/md/dm-io-rewind.c b/drivers/md/dm-io-rewind.c
index fa59ced30faf..0db53ccb94ba 100644
--- a/drivers/md/dm-io-rewind.c
+++ b/drivers/md/dm-io-rewind.c
@@ -131,7 +131,7 @@ static inline void dm_bio_rewind_iter(const struct bio *bio,
  * rewinding from end of bio and restoring its original position.
  * Caller is also responsibile for restoring bio's size.
  */
-void dm_bio_rewind(struct bio *bio, unsigned bytes)
+static void dm_bio_rewind(struct bio *bio, unsigned bytes)
 {
 	if (bio_integrity(bio))
 		dm_bio_integrity_rewind(bio, bytes);
@@ -141,3 +141,26 @@ void dm_bio_rewind(struct bio *bio, unsigned bytes)
 
 	dm_bio_rewind_iter(bio, &bio->bi_iter, bytes);
 }
+
+void dm_io_rewind(struct dm_io *io, struct bio_set *bs)
+{
+	struct bio *orig = io->orig_bio;
+	struct bio *new_orig = bio_alloc_clone(orig->bi_bdev, orig,
+					       GFP_NOIO, bs);
+	/*
+	 * dm_bio_rewind can restore to previous position since the
+	 * end sector is fixed for original bio, but we still need
+	 * to restore bio's size manually (using io->sectors).
+	 */
+	dm_bio_rewind(new_orig, ((io->sector_offset << 9) -
+				 orig->bi_iter.bi_size));
+	bio_trim(new_orig, 0, io->sectors);
+
+	bio_chain(new_orig, orig);
+	/*
+	 * __bi_remaining was increased (by dm_split_and_process_bio),
+	 * so must drop the one added in bio_chain.
+	 */
+	atomic_dec(&orig->__bi_remaining);
+	io->orig_bio = new_orig;
+}
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index c987f9ad24a4..fa6839141118 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -590,7 +590,6 @@ static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio)
 	atomic_set(&io->io_count, 2);
 	this_cpu_inc(*md->pending_io);
 	io->orig_bio = bio;
-	io->split_bio = NULL;
 	io->md = md;
 	spin_lock_init(&io->lock);
 	io->start_time = jiffies;
@@ -880,13 +879,35 @@ static int __noflush_suspending(struct mapped_device *md)
 	return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
 }
 
+static void dm_requeue_add_io(struct dm_io *io, bool first_stage)
+{
+	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)
+static bool dm_handle_requeue(struct dm_io *io, bool first_stage)
 {
-	struct bio *bio = io->split_bio ? io->split_bio : io->orig_bio;
+	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));
@@ -912,8 +933,8 @@ static bool dm_handle_requeue(struct dm_io *io)
 		spin_lock_irqsave(&md->deferred_lock, flags);
 		if ((__noflush_suspending(md) &&
 		     !WARN_ON_ONCE(dm_is_zone_write(md, bio))) ||
-		    handle_polled_eagain) {
-			bio_list_add_head(&md->deferred, bio);
+		    handle_polled_eagain || first_stage) {
+			dm_requeue_add_io(io, first_stage);
 			requeued = true;
 		} else {
 			/*
@@ -926,19 +947,21 @@ static bool dm_handle_requeue(struct dm_io *io)
 	}
 
 	if (requeued)
-		queue_work(md->wq, &md->work);
+		dm_kick_requeue(md, first_stage);
 
 	return requeued;
 }
 
-static void dm_io_complete(struct dm_io *io)
+static void __dm_io_complete(struct dm_io *io, bool first_stage)
 {
-	struct bio *bio = io->split_bio ? io->split_bio : io->orig_bio;
+	struct bio *bio = io->orig_bio;
 	struct mapped_device *md = io->md;
 	blk_status_t io_error;
 	bool requeued;
 
-	requeued = dm_handle_requeue(io);
+	requeued = dm_handle_requeue(io, first_stage);
+	if (requeued && first_stage)
+		return;
 
 	io_error = io->status;
 	if (dm_io_flagged(io, DM_IO_ACCOUNTED))
@@ -978,6 +1001,58 @@ 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.
@@ -1256,6 +1331,7 @@ 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));
@@ -1271,8 +1347,9 @@ 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);
 
@@ -1395,17 +1472,7 @@ 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);
 	}
 }
 
@@ -1705,11 +1772,9 @@ static void dm_split_and_process_bio(struct mapped_device *md,
 	 * Remainder must be passed to submit_bio_noacct() so it gets handled
 	 * *after* bios already submitted have been completely processed.
 	 */
-	WARN_ON_ONCE(!dm_io_flagged(io, DM_IO_WAS_SPLIT));
-	io->split_bio = bio_split(bio, io->sectors, GFP_NOIO,
-				  &md->queue->bio_split);
-	bio_chain(io->split_bio, bio);
-	trace_block_split(io->split_bio, bio->bi_iter.bi_sector);
+	bio_trim(bio, io->sectors, ci.sector_count);
+	trace_block_split(bio, bio->bi_iter.bi_sector);
+	bio_inc_remaining(bio);
 	submit_bio_noacct(bio);
 out:
 	/*
@@ -1985,9 +2050,11 @@ 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);
-- 
cgit v1.2.3


From 2aec377a29250b942f14d3c16d49783da3e9df11 Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@kernel.org>
Date: Tue, 5 Jul 2022 14:00:36 -0400
Subject: dm table: remove dm_table_get_num_targets() wrapper

More efficient and readable to just access table->num_targets directly.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 drivers/md/dm-ima.c           |  2 +-
 drivers/md/dm-ioctl.c         |  6 +++---
 drivers/md/dm-table.c         | 37 ++++++++++++++++---------------------
 drivers/md/dm-zone.c          |  2 +-
 drivers/md/dm.c               |  4 ++--
 include/linux/device-mapper.h |  1 -
 6 files changed, 23 insertions(+), 29 deletions(-)

(limited to 'drivers/md/dm.c')

diff --git a/drivers/md/dm-ima.c b/drivers/md/dm-ima.c
index 1842d3a958ef..3c15c069947f 100644
--- a/drivers/md/dm-ima.c
+++ b/drivers/md/dm-ima.c
@@ -208,7 +208,7 @@ void dm_ima_measure_on_table_load(struct dm_table *table, unsigned int status_fl
 	if (!target_data_buf)
 		goto error;
 
-	num_targets = dm_table_get_num_targets(table);
+	num_targets = table->num_targets;
 
 	if (dm_ima_alloc_and_copy_device_data(table->md, &device_data_buf, num_targets, noio))
 		goto error;
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 87310fceb0d8..98976aaa9db9 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -832,7 +832,7 @@ static void __dev_status(struct mapped_device *md, struct dm_ioctl *param)
 		if (!(param->flags & DM_QUERY_INACTIVE_TABLE_FLAG)) {
 			if (get_disk_ro(disk))
 				param->flags |= DM_READONLY_FLAG;
-			param->target_count = dm_table_get_num_targets(table);
+			param->target_count = table->num_targets;
 		}
 
 		param->flags |= DM_ACTIVE_PRESENT_FLAG;
@@ -845,7 +845,7 @@ static void __dev_status(struct mapped_device *md, struct dm_ioctl *param)
 		if (table) {
 			if (!(dm_table_get_mode(table) & FMODE_WRITE))
 				param->flags |= DM_READONLY_FLAG;
-			param->target_count = dm_table_get_num_targets(table);
+			param->target_count = table->num_targets;
 		}
 		dm_put_live_table(md, srcu_idx);
 	}
@@ -1248,7 +1248,7 @@ static void retrieve_status(struct dm_table *table,
 		type = STATUSTYPE_INFO;
 
 	/* Get all the target info */
-	num_targets = dm_table_get_num_targets(table);
+	num_targets = table->num_targets;
 	for (i = 0; i < num_targets; i++) {
 		struct dm_target *ti = dm_table_get_target(table, i);
 		size_t l;
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 3f29b1113294..b4af34041a6f 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -593,7 +593,7 @@ static int validate_hardware_logical_block_alignment(struct dm_table *table,
 	/*
 	 * Check each entry in the table in turn.
 	 */
-	for (i = 0; i < dm_table_get_num_targets(table); i++) {
+	for (i = 0; i < table->num_targets; i++) {
 		ti = dm_table_get_target(table, i);
 
 		blk_set_stacking_limits(&ti_limits);
@@ -832,7 +832,7 @@ static bool dm_table_supports_dax(struct dm_table *t,
 	unsigned i;
 
 	/* Ensure that all targets support DAX. */
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+	for (i = 0; i < t->num_targets; i++) {
 		ti = dm_table_get_target(t, i);
 
 		if (!ti->type->direct_access)
@@ -987,7 +987,7 @@ struct dm_target *dm_table_get_wildcard_target(struct dm_table *t)
 	struct dm_target *ti;
 	unsigned i;
 
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+	for (i = 0; i < t->num_targets; i++) {
 		ti = dm_table_get_target(t, i);
 		if (dm_target_is_wildcard(ti->type))
 			return ti;
@@ -1127,7 +1127,7 @@ static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t)
 	struct gendisk *prev_disk = NULL, *template_disk = NULL;
 	unsigned i;
 
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+	for (i = 0; i < t->num_targets; i++) {
 		struct dm_target *ti = dm_table_get_target(t, i);
 		if (!dm_target_passes_integrity(ti->type))
 			goto no_integrity;
@@ -1248,7 +1248,7 @@ static int dm_keyslot_evict(struct blk_crypto_profile *profile,
 	t = dm_get_live_table(md, &srcu_idx);
 	if (!t)
 		return 0;
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+	for (i = 0; i < t->num_targets; i++) {
 		ti = dm_table_get_target(t, i);
 		if (!ti->type->iterate_devices)
 			continue;
@@ -1318,7 +1318,7 @@ static int dm_table_construct_crypto_profile(struct dm_table *t)
 	memset(profile->modes_supported, 0xFF,
 	       sizeof(profile->modes_supported));
 
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+	for (i = 0; i < t->num_targets; i++) {
 		ti = dm_table_get_target(t, i);
 
 		if (!dm_target_passes_crypto(ti->type)) {
@@ -1540,7 +1540,7 @@ static bool dm_table_any_dev_attr(struct dm_table *t,
 	struct dm_target *ti;
 	unsigned int i;
 
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+	for (i = 0; i < t->num_targets; i++) {
 		ti = dm_table_get_target(t, i);
 
 		if (ti->type->iterate_devices &&
@@ -1566,7 +1566,7 @@ static bool dm_table_supports_poll(struct dm_table *t)
 	struct dm_target *ti;
 	unsigned i = 0;
 
-	while (i < dm_table_get_num_targets(t)) {
+	while (i < t->num_targets) {
 		ti = dm_table_get_target(t, i++);
 
 		if (!ti->type->iterate_devices ||
@@ -1588,7 +1588,7 @@ bool dm_table_has_no_data_devices(struct dm_table *table)
 	struct dm_target *ti;
 	unsigned i, num_devices;
 
-	for (i = 0; i < dm_table_get_num_targets(table); i++) {
+	for (i = 0; i < table->num_targets; i++) {
 		ti = dm_table_get_target(table, i);
 
 		if (!ti->type->iterate_devices)
@@ -1625,7 +1625,7 @@ static bool dm_table_supports_zoned_model(struct dm_table *t,
 	struct dm_target *ti;
 	unsigned i;
 
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+	for (i = 0; i < t->num_targets; i++) {
 		ti = dm_table_get_target(t, i);
 
 		if (dm_target_supports_zoned_hm(ti->type)) {
@@ -1699,7 +1699,7 @@ int dm_calculate_queue_limits(struct dm_table *table,
 
 	blk_set_stacking_limits(limits);
 
-	for (i = 0; i < dm_table_get_num_targets(table); i++) {
+	for (i = 0; i < table->num_targets; i++) {
 		blk_set_stacking_limits(&ti_limits);
 
 		ti = dm_table_get_target(table, i);
@@ -1819,7 +1819,7 @@ static bool dm_table_supports_flush(struct dm_table *t, unsigned long flush)
 	 * so we need to use iterate_devices here, which targets
 	 * supporting flushes must provide.
 	 */
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+	for (i = 0; i < t->num_targets; i++) {
 		ti = dm_table_get_target(t, i);
 
 		if (!ti->num_flush_bios)
@@ -1877,7 +1877,7 @@ static bool dm_table_supports_write_zeroes(struct dm_table *t)
 	struct dm_target *ti;
 	unsigned i = 0;
 
-	while (i < dm_table_get_num_targets(t)) {
+	while (i < t->num_targets) {
 		ti = dm_table_get_target(t, i++);
 
 		if (!ti->num_write_zeroes_bios)
@@ -1904,7 +1904,7 @@ static bool dm_table_supports_nowait(struct dm_table *t)
 	struct dm_target *ti;
 	unsigned i = 0;
 
-	while (i < dm_table_get_num_targets(t)) {
+	while (i < t->num_targets) {
 		ti = dm_table_get_target(t, i++);
 
 		if (!dm_target_supports_nowait(ti->type))
@@ -1929,7 +1929,7 @@ static bool dm_table_supports_discards(struct dm_table *t)
 	struct dm_target *ti;
 	unsigned i;
 
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+	for (i = 0; i < t->num_targets; i++) {
 		ti = dm_table_get_target(t, i);
 
 		if (!ti->num_discard_bios)
@@ -1961,7 +1961,7 @@ static bool dm_table_supports_secure_erase(struct dm_table *t)
 	struct dm_target *ti;
 	unsigned int i;
 
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+	for (i = 0; i < t->num_targets; i++) {
 		ti = dm_table_get_target(t, i);
 
 		if (!ti->num_secure_erase_bios)
@@ -2092,11 +2092,6 @@ int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 	return 0;
 }
 
-unsigned int dm_table_get_num_targets(struct dm_table *t)
-{
-	return t->num_targets;
-}
-
 struct list_head *dm_table_get_devices(struct dm_table *t)
 {
 	return &t->devices;
diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c
index 3e7b1fe1580b..16dc9ec4bb11 100644
--- a/drivers/md/dm-zone.c
+++ b/drivers/md/dm-zone.c
@@ -278,7 +278,7 @@ static bool dm_table_supports_zone_append(struct dm_table *t)
 	struct dm_target *ti;
 	unsigned int i;
 
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+	for (i = 0; i < t->num_targets; i++) {
 		ti = dm_table_get_target(t, i);
 
 		if (ti->emulate_zone_append)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index fa6839141118..44dae3869f29 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -422,7 +422,7 @@ 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);
@@ -3092,7 +3092,7 @@ 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);
 
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 47a01c7cffdf..920085dd7f3b 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -561,7 +561,6 @@ void dm_sync_table(struct mapped_device *md);
  * Queries
  */
 sector_t dm_table_get_size(struct dm_table *t);
-unsigned int dm_table_get_num_targets(struct dm_table *t);
 fmode_t dm_table_get_mode(struct dm_table *t);
 struct mapped_device *dm_table_get_md(struct dm_table *t);
 const char *dm_table_device_name(struct dm_table *t);
-- 
cgit v1.2.3


From 564b5c5476cdb71b717340897b2b50f9c45df158 Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@kernel.org>
Date: Tue, 5 Jul 2022 16:12:27 -0400
Subject: dm table: audit all dm_table_get_target() callers

All callers of dm_table_get_target() are expected to do proper bounds
checking on the index they pass.

Move dm_table_get_target() to dm-core.h to make it extra clear that only
DM core code should be using it. Switch it to be inlined while at it.

Standardize all DM core callers to use the same for loop pattern and
make associated variables as local as possible. Rename some variables
(e.g. s/table/t/ and s/tgt/ti/) along the way.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 drivers/md/dm-core.h  |   7 ++
 drivers/md/dm-ima.c   |   3 -
 drivers/md/dm-table.c | 200 +++++++++++++++++++-------------------------------
 drivers/md/dm-zone.c  |   7 +-
 drivers/md/dm.c       |  22 +++---
 drivers/md/dm.h       |   1 -
 6 files changed, 97 insertions(+), 143 deletions(-)

(limited to 'drivers/md/dm.c')

diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index 8ef780a6baae..6c6bd24774f2 100644
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -226,6 +226,13 @@ struct dm_table {
 #endif
 };
 
+static inline struct dm_target *dm_table_get_target(struct dm_table *t,
+						    unsigned int index)
+{
+	BUG_ON(index >= t->num_targets);
+	return t->targets + index;
+}
+
 /*
  * One of these is allocated per clone bio.
  */
diff --git a/drivers/md/dm-ima.c b/drivers/md/dm-ima.c
index 3c15c069947f..a1bd7cd52b1b 100644
--- a/drivers/md/dm-ima.c
+++ b/drivers/md/dm-ima.c
@@ -237,9 +237,6 @@ void dm_ima_measure_on_table_load(struct dm_table *table, unsigned int status_fl
 	for (i = 0; i < num_targets; i++) {
 		struct dm_target *ti = dm_table_get_target(table, i);
 
-		if (!ti)
-			goto error;
-
 		last_target_measured = 0;
 
 		/*
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index b4af34041a6f..2f7bdb891013 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -175,8 +175,6 @@ static void dm_table_destroy_crypto_profile(struct dm_table *t);
 
 void dm_table_destroy(struct dm_table *t)
 {
-	unsigned int i;
-
 	if (!t)
 		return;
 
@@ -185,13 +183,13 @@ void dm_table_destroy(struct dm_table *t)
 		kvfree(t->index[t->depth - 2]);
 
 	/* free the targets */
-	for (i = 0; i < t->num_targets; i++) {
-		struct dm_target *tgt = t->targets + i;
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
-		if (tgt->type->dtr)
-			tgt->type->dtr(tgt);
+		if (ti->type->dtr)
+			ti->type->dtr(ti);
 
-		dm_put_target_type(tgt->type);
+		dm_put_target_type(ti->type);
 	}
 
 	kvfree(t->highs);
@@ -451,14 +449,14 @@ EXPORT_SYMBOL(dm_put_device);
 /*
  * Checks to see if the target joins onto the end of the table.
  */
-static int adjoin(struct dm_table *table, struct dm_target *ti)
+static int adjoin(struct dm_table *t, struct dm_target *ti)
 {
 	struct dm_target *prev;
 
-	if (!table->num_targets)
+	if (!t->num_targets)
 		return !ti->begin;
 
-	prev = &table->targets[table->num_targets - 1];
+	prev = &t->targets[t->num_targets - 1];
 	return (ti->begin == (prev->begin + prev->len));
 }
 
@@ -565,8 +563,8 @@ int dm_split_args(int *argc, char ***argvp, char *input)
  * two or more targets, the size of each piece it gets split into must
  * be compatible with the logical_block_size of the target processing it.
  */
-static int validate_hardware_logical_block_alignment(struct dm_table *table,
-						 struct queue_limits *limits)
+static int validate_hardware_logical_block_alignment(struct dm_table *t,
+						     struct queue_limits *limits)
 {
 	/*
 	 * This function uses arithmetic modulo the logical_block_size
@@ -588,13 +586,13 @@ static int validate_hardware_logical_block_alignment(struct dm_table *table,
 
 	struct dm_target *ti;
 	struct queue_limits ti_limits;
-	unsigned i;
+	unsigned int i;
 
 	/*
 	 * Check each entry in the table in turn.
 	 */
-	for (i = 0; i < table->num_targets; i++) {
-		ti = dm_table_get_target(table, i);
+	for (i = 0; i < t->num_targets; i++) {
+		ti = dm_table_get_target(t, i);
 
 		blk_set_stacking_limits(&ti_limits);
 
@@ -622,7 +620,7 @@ static int validate_hardware_logical_block_alignment(struct dm_table *table,
 	if (remaining) {
 		DMWARN("%s: table line %u (start sect %llu len %llu) "
 		       "not aligned to h/w logical block size %u",
-		       dm_device_name(table->md), i,
+		       dm_device_name(t->md), i,
 		       (unsigned long long) ti->begin,
 		       (unsigned long long) ti->len,
 		       limits->logical_block_size);
@@ -826,14 +824,11 @@ static int device_not_dax_synchronous_capable(struct dm_target *ti, struct dm_de
 }
 
 static bool dm_table_supports_dax(struct dm_table *t,
-			   iterate_devices_callout_fn iterate_fn)
+				  iterate_devices_callout_fn iterate_fn)
 {
-	struct dm_target *ti;
-	unsigned i;
-
 	/* Ensure that all targets support DAX. */
-	for (i = 0; i < t->num_targets; i++) {
-		ti = dm_table_get_target(t, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->type->direct_access)
 			return false;
@@ -861,9 +856,8 @@ static int device_is_rq_stackable(struct dm_target *ti, struct dm_dev *dev,
 
 static int dm_table_determine_type(struct dm_table *t)
 {
-	unsigned i;
 	unsigned bio_based = 0, request_based = 0, hybrid = 0;
-	struct dm_target *tgt;
+	struct dm_target *ti;
 	struct list_head *devices = dm_table_get_devices(t);
 	enum dm_queue_mode live_md_type = dm_get_md_type(t->md);
 
@@ -877,11 +871,11 @@ static int dm_table_determine_type(struct dm_table *t)
 		goto verify_rq_based;
 	}
 
-	for (i = 0; i < t->num_targets; i++) {
-		tgt = t->targets + i;
-		if (dm_target_hybrid(tgt))
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		ti = dm_table_get_target(t, i);
+		if (dm_target_hybrid(ti))
 			hybrid = 1;
-		else if (dm_target_request_based(tgt))
+		else if (dm_target_request_based(ti))
 			request_based = 1;
 		else
 			bio_based = 1;
@@ -943,18 +937,18 @@ verify_rq_based:
 		return 0;
 	}
 
-	tgt = dm_table_get_immutable_target(t);
-	if (!tgt) {
+	ti = dm_table_get_immutable_target(t);
+	if (!ti) {
 		DMERR("table load rejected: immutable target is required");
 		return -EINVAL;
-	} else if (tgt->max_io_len) {
+	} else if (ti->max_io_len) {
 		DMERR("table load rejected: immutable target that splits IO is not supported");
 		return -EINVAL;
 	}
 
 	/* Non-request-stackable devices can't be used for request-based dm */
-	if (!tgt->type->iterate_devices ||
-	    !tgt->type->iterate_devices(tgt, device_is_rq_stackable, NULL)) {
+	if (!ti->type->iterate_devices ||
+	    !ti->type->iterate_devices(ti, device_is_rq_stackable, NULL)) {
 		DMERR("table load rejected: including non-request-stackable devices");
 		return -EINVAL;
 	}
@@ -984,11 +978,9 @@ struct dm_target *dm_table_get_immutable_target(struct dm_table *t)
 
 struct dm_target *dm_table_get_wildcard_target(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned i;
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
-	for (i = 0; i < t->num_targets; i++) {
-		ti = dm_table_get_target(t, i);
 		if (dm_target_is_wildcard(ti->type))
 			return ti;
 	}
@@ -1031,7 +1023,7 @@ static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *
 	}
 
 	for (unsigned int i = 0; i < t->num_targets; i++) {
-		struct dm_target *ti = t->targets + i;
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		per_io_data_size = max(per_io_data_size, ti->per_io_data_size);
 		min_pool_size = max(min_pool_size, ti->num_flush_bios);
@@ -1125,10 +1117,10 @@ static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t)
 	struct list_head *devices = dm_table_get_devices(t);
 	struct dm_dev_internal *dd = NULL;
 	struct gendisk *prev_disk = NULL, *template_disk = NULL;
-	unsigned i;
 
-	for (i = 0; i < t->num_targets; i++) {
+	for (unsigned int i = 0; i < t->num_targets; i++) {
 		struct dm_target *ti = dm_table_get_target(t, i);
+
 		if (!dm_target_passes_integrity(ti->type))
 			goto no_integrity;
 	}
@@ -1242,18 +1234,19 @@ static int dm_keyslot_evict(struct blk_crypto_profile *profile,
 	struct dm_keyslot_evict_args args = { key };
 	struct dm_table *t;
 	int srcu_idx;
-	int i;
-	struct dm_target *ti;
 
 	t = dm_get_live_table(md, &srcu_idx);
 	if (!t)
 		return 0;
-	for (i = 0; i < t->num_targets; i++) {
-		ti = dm_table_get_target(t, i);
+
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
+
 		if (!ti->type->iterate_devices)
 			continue;
 		ti->type->iterate_devices(ti, dm_keyslot_evict_callback, &args);
 	}
+
 	dm_put_live_table(md, srcu_idx);
 	return args.err;
 }
@@ -1302,7 +1295,6 @@ static int dm_table_construct_crypto_profile(struct dm_table *t)
 {
 	struct dm_crypto_profile *dmcp;
 	struct blk_crypto_profile *profile;
-	struct dm_target *ti;
 	unsigned int i;
 	bool empty_profile = true;
 
@@ -1319,7 +1311,7 @@ static int dm_table_construct_crypto_profile(struct dm_table *t)
 	       sizeof(profile->modes_supported));
 
 	for (i = 0; i < t->num_targets; i++) {
-		ti = dm_table_get_target(t, i);
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!dm_target_passes_crypto(ti->type)) {
 			blk_crypto_intersect_capabilities(profile, NULL);
@@ -1469,14 +1461,6 @@ inline sector_t dm_table_get_size(struct dm_table *t)
 }
 EXPORT_SYMBOL(dm_table_get_size);
 
-struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
-{
-	if (index >= t->num_targets)
-		return NULL;
-
-	return t->targets + index;
-}
-
 /*
  * Search the btree for the correct target.
  *
@@ -1537,11 +1521,8 @@ static int device_not_poll_capable(struct dm_target *ti, struct dm_dev *dev,
 static bool dm_table_any_dev_attr(struct dm_table *t,
 				  iterate_devices_callout_fn func, void *data)
 {
-	struct dm_target *ti;
-	unsigned int i;
-
-	for (i = 0; i < t->num_targets; i++) {
-		ti = dm_table_get_target(t, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (ti->type->iterate_devices &&
 		    ti->type->iterate_devices(ti, func, data))
@@ -1563,11 +1544,8 @@ static int count_device(struct dm_target *ti, struct dm_dev *dev,
 
 static bool dm_table_supports_poll(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned i = 0;
-
-	while (i < t->num_targets) {
-		ti = dm_table_get_target(t, i++);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->type->iterate_devices ||
 		    ti->type->iterate_devices(ti, device_not_poll_capable, NULL))
@@ -1583,18 +1561,15 @@ static bool dm_table_supports_poll(struct dm_table *t)
  * Returns false if the result is unknown because a target doesn't
  * support iterate_devices.
  */
-bool dm_table_has_no_data_devices(struct dm_table *table)
+bool dm_table_has_no_data_devices(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned i, num_devices;
-
-	for (i = 0; i < table->num_targets; i++) {
-		ti = dm_table_get_target(table, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
+		unsigned num_devices = 0;
 
 		if (!ti->type->iterate_devices)
 			return false;
 
-		num_devices = 0;
 		ti->type->iterate_devices(ti, count_device, &num_devices);
 		if (num_devices)
 			return false;
@@ -1622,11 +1597,8 @@ static int device_not_zoned_model(struct dm_target *ti, struct dm_dev *dev,
 static bool dm_table_supports_zoned_model(struct dm_table *t,
 					  enum blk_zoned_model zoned_model)
 {
-	struct dm_target *ti;
-	unsigned i;
-
-	for (i = 0; i < t->num_targets; i++) {
-		ti = dm_table_get_target(t, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (dm_target_supports_zoned_hm(ti->type)) {
 			if (!ti->type->iterate_devices ||
@@ -1659,16 +1631,16 @@ static int device_not_matches_zone_sectors(struct dm_target *ti, struct dm_dev *
  * zone sectors, if the destination device is a zoned block device, it shall
  * have the specified zone_sectors.
  */
-static int validate_hardware_zoned_model(struct dm_table *table,
+static int validate_hardware_zoned_model(struct dm_table *t,
 					 enum blk_zoned_model zoned_model,
 					 unsigned int zone_sectors)
 {
 	if (zoned_model == BLK_ZONED_NONE)
 		return 0;
 
-	if (!dm_table_supports_zoned_model(table, zoned_model)) {
+	if (!dm_table_supports_zoned_model(t, zoned_model)) {
 		DMERR("%s: zoned model is not consistent across all devices",
-		      dm_device_name(table->md));
+		      dm_device_name(t->md));
 		return -EINVAL;
 	}
 
@@ -1676,9 +1648,9 @@ static int validate_hardware_zoned_model(struct dm_table *table,
 	if (!zone_sectors || !is_power_of_2(zone_sectors))
 		return -EINVAL;
 
-	if (dm_table_any_dev_attr(table, device_not_matches_zone_sectors, &zone_sectors)) {
+	if (dm_table_any_dev_attr(t, device_not_matches_zone_sectors, &zone_sectors)) {
 		DMERR("%s: zone sectors is not consistent across all zoned devices",
-		      dm_device_name(table->md));
+		      dm_device_name(t->md));
 		return -EINVAL;
 	}
 
@@ -1688,21 +1660,19 @@ static int validate_hardware_zoned_model(struct dm_table *table,
 /*
  * Establish the new table's queue_limits and validate them.
  */
-int dm_calculate_queue_limits(struct dm_table *table,
+int dm_calculate_queue_limits(struct dm_table *t,
 			      struct queue_limits *limits)
 {
-	struct dm_target *ti;
 	struct queue_limits ti_limits;
-	unsigned i;
 	enum blk_zoned_model zoned_model = BLK_ZONED_NONE;
 	unsigned int zone_sectors = 0;
 
 	blk_set_stacking_limits(limits);
 
-	for (i = 0; i < table->num_targets; i++) {
-		blk_set_stacking_limits(&ti_limits);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
-		ti = dm_table_get_target(table, i);
+		blk_set_stacking_limits(&ti_limits);
 
 		if (!ti->type->iterate_devices)
 			goto combine_limits;
@@ -1743,7 +1713,7 @@ combine_limits:
 			DMWARN("%s: adding target device "
 			       "(start sect %llu len %llu) "
 			       "caused an alignment inconsistency",
-			       dm_device_name(table->md),
+			       dm_device_name(t->md),
 			       (unsigned long long) ti->begin,
 			       (unsigned long long) ti->len);
 	}
@@ -1763,10 +1733,10 @@ combine_limits:
 		zoned_model = limits->zoned;
 		zone_sectors = limits->chunk_sectors;
 	}
-	if (validate_hardware_zoned_model(table, zoned_model, zone_sectors))
+	if (validate_hardware_zoned_model(t, zoned_model, zone_sectors))
 		return -EINVAL;
 
-	return validate_hardware_logical_block_alignment(table, limits);
+	return validate_hardware_logical_block_alignment(t, limits);
 }
 
 /*
@@ -1810,17 +1780,14 @@ static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
 
 static bool dm_table_supports_flush(struct dm_table *t, unsigned long flush)
 {
-	struct dm_target *ti;
-	unsigned i;
-
 	/*
 	 * Require at least one underlying device to support flushes.
 	 * t->devices includes internal dm devices such as mirror logs
 	 * so we need to use iterate_devices here, which targets
 	 * supporting flushes must provide.
 	 */
-	for (i = 0; i < t->num_targets; i++) {
-		ti = dm_table_get_target(t, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->num_flush_bios)
 			continue;
@@ -1874,11 +1841,8 @@ static int device_not_write_zeroes_capable(struct dm_target *ti, struct dm_dev *
 
 static bool dm_table_supports_write_zeroes(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned i = 0;
-
-	while (i < t->num_targets) {
-		ti = dm_table_get_target(t, i++);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->num_write_zeroes_bios)
 			return false;
@@ -1901,11 +1865,8 @@ static int device_not_nowait_capable(struct dm_target *ti, struct dm_dev *dev,
 
 static bool dm_table_supports_nowait(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned i = 0;
-
-	while (i < t->num_targets) {
-		ti = dm_table_get_target(t, i++);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!dm_target_supports_nowait(ti->type))
 			return false;
@@ -1926,11 +1887,8 @@ static int device_not_discard_capable(struct dm_target *ti, struct dm_dev *dev,
 
 static bool dm_table_supports_discards(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned i;
-
-	for (i = 0; i < t->num_targets; i++) {
-		ti = dm_table_get_target(t, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->num_discard_bios)
 			return false;
@@ -1958,11 +1916,8 @@ static int device_not_secure_erase_capable(struct dm_target *ti,
 
 static bool dm_table_supports_secure_erase(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned int i;
-
-	for (i = 0; i < t->num_targets; i++) {
-		ti = dm_table_get_target(t, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->num_secure_erase_bios)
 			return false;
@@ -2111,12 +2066,11 @@ enum suspend_mode {
 
 static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
 {
-	int i = t->num_targets;
-	struct dm_target *ti = t->targets;
-
 	lockdep_assert_held(&t->md->suspend_lock);
 
-	while (i--) {
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
+
 		switch (mode) {
 		case PRESUSPEND:
 			if (ti->type->presuspend)
@@ -2131,7 +2085,6 @@ static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
 				ti->type->postsuspend(ti);
 			break;
 		}
-		ti++;
 	}
 }
 
@@ -2161,12 +2114,13 @@ void dm_table_postsuspend_targets(struct dm_table *t)
 
 int dm_table_resume_targets(struct dm_table *t)
 {
-	int i, r = 0;
+	unsigned int i;
+	int r = 0;
 
 	lockdep_assert_held(&t->md->suspend_lock);
 
 	for (i = 0; i < t->num_targets; i++) {
-		struct dm_target *ti = t->targets + i;
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->type->preresume)
 			continue;
@@ -2180,7 +2134,7 @@ int dm_table_resume_targets(struct dm_table *t)
 	}
 
 	for (i = 0; i < t->num_targets; i++) {
-		struct dm_target *ti = t->targets + i;
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (ti->type->resume)
 			ti->type->resume(ti);
diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c
index 16dc9ec4bb11..444ca81f4596 100644
--- a/drivers/md/dm-zone.c
+++ b/drivers/md/dm-zone.c
@@ -275,11 +275,8 @@ static int device_not_zone_append_capable(struct dm_target *ti,
 
 static bool dm_table_supports_zone_append(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned int i;
-
-	for (i = 0; i < t->num_targets; i++) {
-		ti = dm_table_get_target(t, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (ti->emulate_zone_append)
 			return false;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 44dae3869f29..560ad05497a9 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -411,7 +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;
 
@@ -425,14 +425,14 @@ retry:
 	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);
@@ -1506,11 +1506,11 @@ 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:
@@ -1538,8 +1538,7 @@ 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;
 
 	/*
@@ -1554,8 +1553,9 @@ 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);
@@ -1575,7 +1575,7 @@ 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)));
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 62816b647f82..5201df03ce40 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -53,7 +53,6 @@ struct dm_io;
  *---------------------------------------------------------------*/
 void dm_table_event_callback(struct dm_table *t,
 			     void (*fn)(void *), void *context);
-struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
 bool dm_table_has_no_data_devices(struct dm_table *table);
 int dm_calculate_queue_limits(struct dm_table *table,
-- 
cgit v1.2.3


From e120a5f1e78fab6223544e425015f393d90d6f0d Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@kernel.org>
Date: Fri, 22 Jul 2022 15:31:23 -0400
Subject: dm: return early from dm_pr_call() if DM device is suspended

Otherwise PR ops may be issued while the broader DM device is being
reconfigured, etc.

Fixes: 9c72bad1f31a ("dm: call PR reserve/unreserve on each underlying device")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 drivers/md/dm.c | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'drivers/md/dm.c')

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 560ad05497a9..e44415daa98f 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -3096,6 +3096,11 @@ static int dm_call_pr(struct block_device *bdev, iterate_devices_callout_fn fn,
 		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;
-- 
cgit v1.2.3


From 8dd87f3c5283de7f95396a236e420487226f3951 Mon Sep 17 00:00:00 2001
From: Mike Christie <michael.christie@oracle.com>
Date: Sun, 17 Jul 2022 17:45:05 -0500
Subject: dm: Allow dm_call_pr to be used for path searches

The specs state that if you send a reserve down a path that is already
the holder success must be returned and if it goes down a path that
is not the holder reservation conflict must be returned. Windows
failover clustering will send a second reservation and expects that a
device returns success. The problem for multipathing is that for an
All Registrants reservation, we can send the reserve down any path but
for all other reservation types there is one path that is the holder.

To handle this we could add PR state to dm but that can get nasty.
Look at target_core_pr.c for an example of the type of things we'd
have to track. It will also get more complicated because other
initiators can change the state so we will have to add in async
event/sense handling.

This commit, and the 3 commits that follow, tries to keep dm simple
and keep just doing passthrough. This commit modifies dm_call_pr to be
able to find the first usable path that can execute our pr_op then
return. When dm_pr_reserve is converted to dm_call_pr in the next
commit for the normal case we will use the same path for every
reserve.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 drivers/md/dm.c | 50 ++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 38 insertions(+), 12 deletions(-)

(limited to 'drivers/md/dm.c')

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index e44415daa98f..15fc2eaa80a6 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -3077,10 +3077,11 @@ struct dm_pr {
 	u64	new_key;
 	u32	flags;
 	bool	fail_early;
+	int	ret;
 };
 
 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;
@@ -3105,7 +3106,8 @@ static int dm_call_pr(struct block_device *bdev, iterate_devices_callout_fn fn,
 	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;
@@ -3119,10 +3121,24 @@ 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 (!ops || !ops->pr_register)
-		return -EOPNOTSUPP;
-	return ops->pr_register(dev->bdev, pr->old_key, pr->new_key, pr->flags);
+	if (pr->fail_early)
+		return -1;
+
+	return 0;
 }
 
 static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
@@ -3133,19 +3149,29 @@ 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;
 }
 
-- 
cgit v1.2.3


From 701510875975ed7e188566de205990d29f34c8d8 Mon Sep 17 00:00:00 2001
From: Mike Christie <michael.christie@oracle.com>
Date: Sun, 17 Jul 2022 17:45:06 -0500
Subject: dm: Start pr_reserve from the same starting path

When an app does a pr_reserve it will go to whatever path we happen to
be using at the time. This can result in errors when the app does a
second pr_reserve call and expects success but gets a failure because
the reserve is not done on the holder's path. This commit has us
always start trying to do reserves from the first path in the first
group.

Windows failover clustering will produce the type of pattern above.
With this commit, we will now pass its validation test for this case.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 drivers/md/dm.c | 46 ++++++++++++++++++++++++++++++++--------------
 1 file changed, 32 insertions(+), 14 deletions(-)

(limited to 'drivers/md/dm.c')

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 15fc2eaa80a6..ede5feb3d778 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -3078,6 +3078,7 @@ struct dm_pr {
 	u32	flags;
 	bool	fail_early;
 	int	ret;
+	enum pr_type type;
 };
 
 static int dm_call_pr(struct block_device *bdev, iterate_devices_callout_fn fn,
@@ -3175,25 +3176,42 @@ static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
 	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;
 }
 
 static int dm_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
-- 
cgit v1.2.3


From 08a3c338e080d25dd5613a22d71741f19fc0e0fa Mon Sep 17 00:00:00 2001
From: Mike Christie <michael.christie@oracle.com>
Date: Sun, 17 Jul 2022 17:45:07 -0500
Subject: dm: Fix PR release handling for non All Registrants

This commit fixes a bug where we are leaving the reservation in place
even though pr_release has run and returned success.

If we have a Write Exclusive, Exclusive Access, or Write/Exclusive
Registrants only reservation, the release must be sent down the path
that is the reservation holder. The problem is multipath_prepare_ioctl
most likely selected path N for the reservation, then later when we do
the release multipath_prepare_ioctl will select a completely different
path. The device will then return success becuase the nvme and scsi
specs say to return success if there is no reservation or if the
release is sent down from a path that is not the holder. We then think
we have released the reservation.

This commit has us loop over each path and send a release so we can
make sure the release is executed on the correct path. It has been
tested with windows failover clustering's validation test which checks
this case, and it has been tested manually (the libiscsi PGR tests
don't have a test case for this yet, but I will be adding one).

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 drivers/md/dm.c | 48 ++++++++++++++++++++++++++++++++++--------------
 1 file changed, 34 insertions(+), 14 deletions(-)

(limited to 'drivers/md/dm.c')

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index ede5feb3d778..9ce87ddf5249 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -3214,24 +3214,44 @@ static int dm_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type,
 	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 block_device *bdev, u64 old_key, u64 new_key,
-- 
cgit v1.2.3


From c6adada5b70403d526e0ac5b5c50ae245ac92bc7 Mon Sep 17 00:00:00 2001
From: Mike Christie <michael.christie@oracle.com>
Date: Sun, 17 Jul 2022 17:45:08 -0500
Subject: dm: Start pr_preempt from the same starting path

pr_preempt has a similar issue as reserve where for all the
reservation types except the All Registrants ones the preempt can
create a reservation. And a follow up reservation or release needs to
go down the same path the preempt did. This has the pr_preempt work
like reserve and release where we always start from the first path in
the first group.

This commit has been tested with windows failover clustering's
validation test and libiscsi's PGR tests to check for regressions.
They both don't have tests to verify this case, so I tested it
manually.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 drivers/md/dm.c | 45 +++++++++++++++++++++++++++++++--------------
 1 file changed, 31 insertions(+), 14 deletions(-)

(limited to 'drivers/md/dm.c')

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 9ce87ddf5249..47bcc5081b2b 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -3076,6 +3076,7 @@ struct dm_pr {
 	u64	old_key;
 	u64	new_key;
 	u32	flags;
+	bool	abort;
 	bool	fail_early;
 	int	ret;
 	enum pr_type type;
@@ -3254,25 +3255,41 @@ static int dm_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
 	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)
-- 
cgit v1.2.3


From 9dd1cd3220eca534f2d47afad7ce85f4c40118d8 Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@kernel.org>
Date: Wed, 20 Jul 2022 13:58:04 -0400
Subject: dm: fix dm-raid crash if md_handle_request() splits bio

Commit ca522482e3eaf ("dm: pass NULL bdev to bio_alloc_clone")
introduced the optimization to _not_ perform bio_associate_blkg()'s
relatively costly work when DM core clones its bio. But in doing so it
exposed the possibility for DM's cloned bio to alter DM target
behavior (e.g. crash) if a target were to issue IO without first
calling bio_set_dev().

The DM raid target can trigger an MD crash due to its need to split
the DM bio that is passed to md_handle_request(). The split will
recurse to submit_bio_noacct() using a bio with an uninitialized
->bi_blkg. This NULL bio->bi_blkg causes blk_throtl_bio() to
dereference a NULL blkg_to_tg(bio->bi_blkg).

Fix this in DM core by adding a new 'needs_bio_set_dev' target flag that
will make alloc_tio() call bio_set_dev() on behalf of the target.
dm-raid is the only target that requires this flag. bio_set_dev()
initializes the DM cloned bio's ->bi_blkg, using bio_associate_blkg,
before passing the bio to md_handle_request().

Long-term fix would be to audit and refactor MD code to rely on DM to
split its bio, using dm_accept_partial_bio(), but there are MD raid
personalities (e.g. raid1 and raid10) whose implementation are tightly
coupled to handling the bio splitting inline.

Fixes: ca522482e3eaf ("dm: pass NULL bdev to bio_alloc_clone")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 drivers/md/dm-raid.c          |  1 +
 drivers/md/dm.c               | 13 ++++++-------
 include/linux/device-mapper.h |  6 ++++++
 include/uapi/linux/dm-ioctl.h |  4 ++--
 4 files changed, 15 insertions(+), 9 deletions(-)

(limited to 'drivers/md/dm.c')

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index e6a9b8cb22d3..3203aecd6961 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -3095,6 +3095,7 @@ static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	INIT_WORK(&rs->md.event_work, do_table_event);
 	ti->private = rs;
 	ti->num_flush_bios = 1;
+	ti->needs_bio_set_dev = true;
 
 	/* Restore any requested new layout for conversion decision */
 	rs_config_restore(rs, &rs_layout);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 47bcc5081b2b..f6a6437d0a7c 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -574,9 +574,6 @@ static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio)
 	struct bio *clone;
 
 	clone = bio_alloc_clone(NULL, bio, GFP_NOIO, &md->mempools->io_bs);
-	/* Set default bdev, but target must bio_set_dev() before issuing IO */
-	clone->bi_bdev = md->disk->part0;
-
 	tio = clone_to_tio(clone);
 	tio->flags = 0;
 	dm_tio_set_flag(tio, DM_TIO_INSIDE_DM_IO);
@@ -609,6 +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;
 
@@ -618,14 +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->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;
@@ -641,6 +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))
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 920085dd7f3b..04c6acf7faaa 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -373,6 +373,12 @@ struct dm_target {
 	 * after returning DM_MAPIO_SUBMITTED from its map function.
 	 */
 	bool accounts_remapped_io:1;
+
+	/*
+	 * Set if the target will submit the DM bio without first calling
+	 * bio_set_dev(). NOTE: ideally a target should _not_ need this.
+	 */
+	bool needs_bio_set_dev:1;
 };
 
 void *dm_per_bio_data(struct bio *bio, size_t data_size);
diff --git a/include/uapi/linux/dm-ioctl.h b/include/uapi/linux/dm-ioctl.h
index 2e9550fef90f..27ad9671f2df 100644
--- a/include/uapi/linux/dm-ioctl.h
+++ b/include/uapi/linux/dm-ioctl.h
@@ -286,9 +286,9 @@ enum {
 #define DM_DEV_SET_GEOMETRY	_IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
 
 #define DM_VERSION_MAJOR	4
-#define DM_VERSION_MINOR	46
+#define DM_VERSION_MINOR	47
 #define DM_VERSION_PATCHLEVEL	0
-#define DM_VERSION_EXTRA	"-ioctl (2022-02-22)"
+#define DM_VERSION_EXTRA	"-ioctl (2022-07-28)"
 
 /* Status bits */
 #define DM_READONLY_FLAG	(1 << 0) /* In/Out */
-- 
cgit v1.2.3