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authorMike Snitzer <snitzer@redhat.com>2015-03-30 13:39:09 -0400
committerJens Axboe <axboe@fb.com>2015-03-31 09:45:50 -0600
commite9637415a92cf25ad800b7fdeddcd30cce7b44ab (patch)
tree81fb7a27d9d7803fe93745e1a3a1c5f984b8af97 /block/blk-settings.c
parente42391cd048809d903291d07f86ed3934ce138e9 (diff)
downloadlinux-linaro-stable-e9637415a92cf25ad800b7fdeddcd30cce7b44ab.tar.gz
block: fix blk_stack_limits() regression due to lcm() change
Linux 3.19 commit 69c953c ("lib/lcm.c: lcm(n,0)=lcm(0,n) is 0, not n") caused blk_stack_limits() to not properly stack queue_limits for stacked devices (e.g. DM). Fix this regression by establishing lcm_not_zero() and switching blk_stack_limits() over to using it. DM uses blk_set_stacking_limits() to establish the initial top-level queue_limits that are then built up based on underlying devices' limits using blk_stack_limits(). In the case of optimal_io_size (io_opt) blk_set_stacking_limits() establishes a default value of 0. With commit 69c953c, lcm(0, n) is no longer n, which compromises proper stacking of the underlying devices' io_opt. Test: $ modprobe scsi_debug dev_size_mb=10 num_tgts=1 opt_blks=1536 $ cat /sys/block/sde/queue/optimal_io_size 786432 $ dmsetup create node --table "0 100 linear /dev/sde 0" Before this fix: $ cat /sys/block/dm-5/queue/optimal_io_size 0 After this fix: $ cat /sys/block/dm-5/queue/optimal_io_size 786432 Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 3.19+ Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-settings.c')
-rw-r--r--block/blk-settings.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 6ed2cbe5e8c9..12600bfffca9 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -585,7 +585,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
b->physical_block_size);
t->io_min = max(t->io_min, b->io_min);
- t->io_opt = lcm(t->io_opt, b->io_opt);
+ t->io_opt = lcm_not_zero(t->io_opt, b->io_opt);
t->cluster &= b->cluster;
t->discard_zeroes_data &= b->discard_zeroes_data;
@@ -616,7 +616,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
b->raid_partial_stripes_expensive);
/* Find lowest common alignment_offset */
- t->alignment_offset = lcm(t->alignment_offset, alignment)
+ t->alignment_offset = lcm_not_zero(t->alignment_offset, alignment)
% max(t->physical_block_size, t->io_min);
/* Verify that new alignment_offset is on a logical block boundary */
@@ -643,7 +643,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
b->max_discard_sectors);
t->discard_granularity = max(t->discard_granularity,
b->discard_granularity);
- t->discard_alignment = lcm(t->discard_alignment, alignment) %
+ t->discard_alignment = lcm_not_zero(t->discard_alignment, alignment) %
t->discard_granularity;
}