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author | Mike Snitzer <snitzer@redhat.com> | 2020-12-01 11:07:09 -0500 |
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committer | Jens Axboe <axboe@kernel.dk> | 2020-12-01 11:02:55 -0700 |
commit | 7e7986f9d3ba69a7375a41080a1f8c8012cb0923 (patch) | |
tree | a6a6d281c2ce2d02b08e70cb69b06bb88d447bc5 /block/blk-settings.c | |
parent | 47a846536e1bf62626f1c0d8488f3718ce5f8296 (diff) | |
download | linux-7e7986f9d3ba69a7375a41080a1f8c8012cb0923.tar.bz2 |
block: use gcd() to fix chunk_sectors limit stacking
commit 22ada802ede8 ("block: use lcm_not_zero() when stacking
chunk_sectors") broke chunk_sectors limit stacking. chunk_sectors must
reflect the most limited of all devices in the IO stack.
Otherwise malformed IO may result. E.g.: prior to this fix,
->chunk_sectors = lcm_not_zero(8, 128) would result in
blk_max_size_offset() splitting IO at 128 sectors rather than the
required more restrictive 8 sectors.
And since commit 07d098e6bbad ("block: allow 'chunk_sectors' to be
non-power-of-2") care must be taken to properly stack chunk_sectors to
be compatible with the possibility that a non-power-of-2 chunk_sectors
may be stacked. This is why gcd() is used instead of reverting back
to using min_not_zero().
Fixes: 22ada802ede8 ("block: use lcm_not_zero() when stacking chunk_sectors")
Fixes: 07d098e6bbad ("block: allow 'chunk_sectors' to be non-power-of-2")
Reported-by: John Dorminy <jdorminy@redhat.com>
Reported-by: Bruce Johnston <bjohnsto@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: John Dorminy <jdorminy@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-settings.c')
-rw-r--r-- | block/blk-settings.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c index 9741d1d83e98..659cdb8a07fe 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -547,7 +547,10 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, t->io_min = max(t->io_min, b->io_min); t->io_opt = lcm_not_zero(t->io_opt, b->io_opt); - t->chunk_sectors = lcm_not_zero(t->chunk_sectors, b->chunk_sectors); + + /* Set non-power-of-2 compatible chunk_sectors boundary */ + if (b->chunk_sectors) + t->chunk_sectors = gcd(t->chunk_sectors, b->chunk_sectors); /* Physical block size a multiple of the logical block size? */ if (t->physical_block_size & (t->logical_block_size - 1)) { |