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block: use lcm_not_zero() when stacking chunk_sectors 

Like 'io_opt', blk_stack_limits() should stack 'chunk_sectors' using
lcm_not_zero() rather than min_not_zero() -- otherwise the final
'chunk_sectors' could result in sub-optimal alignment of IO to
component devices in the IO stack.

Also, if 'chunk_sectors' isn't a multiple of 'physical_block_size'
then it is a bug in the driver and the device should be flagged as
'misaligned'.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Mike Snitzer 2020-09-21 22:32:48 -04:00 committed by Jens Axboe
parent 0385971754
commit 22ada802ed
1 changed files with 8 additions and 4 deletions
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12
block/blk-settings.c
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@ -534,6 +534,7 @@ 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);
/* Physical block size a multiple of the logical block size? */
if (t->physical_block_size & (t->logical_block_size - 1)) {
@ -556,6 +557,13 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
ret = -1;
}
/* chunk_sectors a multiple of the physical block size? */
if ((t->chunk_sectors << 9) & (t->physical_block_size - 1)) {
t->chunk_sectors = 0;
t->misaligned = 1;
ret = -1;
}
t->raid_partial_stripes_expensive =
max(t->raid_partial_stripes_expensive,
b->raid_partial_stripes_expensive);
@ -594,10 +602,6 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
t->discard_granularity;
}
if (b->chunk_sectors)
t->chunk_sectors = min_not_zero(t->chunk_sectors,
b->chunk_sectors);
t->zoned = max(t->zoned, b->zoned);
return ret;
}