diff options
| author | Mike Snitzer <snitzer@redhat.com> | 2014-10-08 18:26:13 -0400 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-12-14 16:23:47 +0000 |
| commit | 5c250851e1f7850dfe765ff8f6d04ef4ce6e19a7 (patch) | |
| tree | 9af55862b03ee366c8e160ce06b2d371f14a1861 /block | |
| parent | a59a6d8aad7120f8cf6b2393d2a1463de0c1ba6c (diff) | |
block: fix alignment_offset math that assumes io_min is a power-of-2
commit b8839b8c55f3fdd60dc36abcda7e0266aff7985c upstream.
The math in both blk_stack_limits() and queue_limit_alignment_offset()
assume that a block device's io_min (aka minimum_io_size) is always a
power-of-2. Fix the math such that it works for non-power-of-2 io_min.
This issue (of alignment_offset != 0) became apparent when testing
dm-thinp with a thinp blocksize that matches a RAID6 stripesize of
1280K. Commit fdfb4c8c1 ("dm thin: set minimum_io_size to pool's data
block size") unlocked the potential for alignment_offset != 0 due to
the dm-thin-pool's io_min possibly being a non-power-of-2.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-settings.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c index fa1eb0449a05..d55a3e4783e4 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -521,7 +521,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, bottom = max(b->physical_block_size, b->io_min) + alignment; /* Verify that top and bottom intervals line up */ - if (max(top, bottom) & (min(top, bottom) - 1)) { + if (max(top, bottom) % min(top, bottom)) { t->misaligned = 1; ret = -1; } @@ -562,7 +562,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, /* Find lowest common alignment_offset */ t->alignment_offset = lcm(t->alignment_offset, alignment) - & (max(t->physical_block_size, t->io_min) - 1); + % max(t->physical_block_size, t->io_min); /* Verify that new alignment_offset is on a logical block boundary */ if (t->alignment_offset & (t->logical_block_size - 1)) { |