Commit 65f33b35 authored Dec 04, 2020 by Mike Snitzer

block: fix incorrect branching in blk_max_size_offset()



If non-zero 'chunk_sectors' is passed in to blk_max_size_offset() that
override will be incorrectly ignored.

Old blk_max_size_offset() branching, prior to commit 3ee16db3,
must be used only if passed 'chunk_sectors' override is zero.

Fixes: 3ee16db3 ("dm: fix IO splitting")
Cc: stable@vger.kernel.org # 5.9
Reported-by: John Dorminy <jdorminy@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

parent bde3808b

include/linux/blkdev.h

+6 −4

Original line number	Diff line number	Diff line
		@@ -1076,10 +1076,12 @@ static inline unsigned int blk_max_size_offset(struct request_queue *q,
		sector_t offset,
		unsigned int chunk_sectors)
		{
		if (!chunk_sectors && q->limits.chunk_sectors)
		if (!chunk_sectors) {
		if (q->limits.chunk_sectors)
		chunk_sectors = q->limits.chunk_sectors;
		else
		return q->limits.max_sectors;
		}

		if (likely(is_power_of_2(chunk_sectors)))
		chunk_sectors -= offset & (chunk_sectors - 1);

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