diff options
| author | Mike Snitzer <snitzer@redhat.com> | 2020-09-21 22:32:49 -0400 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-09-23 10:38:14 -0600 |
| commit | 07d098e6bbad04030dab5b3e64149601fcb063ce (patch) | |
| tree | 43d4d82eda0a5ea4e466a5ac0fd2125865e65b11 | |
| parent | 22ada802ede89829dd010a317d9b812b7df7111a (diff) | |
block: allow 'chunk_sectors' to be non-power-of-2
It is possible, albeit more unlikely, for a block device to have a non
power-of-2 for chunk_sectors (e.g. 10+2 RAID6 with 128K chunk_sectors,
which results in a full-stripe size of 1280K. This causes the RAID6's
io_opt to be advertised as 1280K, and a stacked device _could_ then be
made to use a blocksize, aka chunk_sectors, that matches non power-of-2
io_opt of underlying RAID6 -- resulting in stacked device's
chunk_sectors being a non power-of-2).
Update blk_queue_chunk_sectors() and blk_max_size_offset() to
accommodate drivers that need a non power-of-2 chunk_sectors.
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>
| -rw-r--r-- | block/blk-settings.c | 10 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 12 |
2 files changed, 13 insertions, 9 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c index b2e1a929a6db..5ea3de48afba 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -172,15 +172,13 @@ EXPORT_SYMBOL(blk_queue_max_hw_sectors); * * Description: * If a driver doesn't want IOs to cross a given chunk size, it can set - * this limit and prevent merging across chunks. Note that the chunk size - * must currently be a power-of-2 in sectors. Also note that the block - * layer must accept a page worth of data at any offset. So if the - * crossing of chunks is a hard limitation in the driver, it must still be - * prepared to split single page bios. + * this limit and prevent merging across chunks. Note that the block layer + * must accept a page worth of data at any offset. So if the crossing of + * chunks is a hard limitation in the driver, it must still be prepared + * to split single page bios. **/ void blk_queue_chunk_sectors(struct request_queue *q, unsigned int chunk_sectors) { - BUG_ON(!is_power_of_2(chunk_sectors)); q->limits.chunk_sectors = chunk_sectors; } EXPORT_SYMBOL(blk_queue_chunk_sectors); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 5bd96fbab9b4..6e19a7aa1672 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1063,11 +1063,17 @@ static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q, static inline unsigned int blk_max_size_offset(struct request_queue *q, sector_t offset) { - if (!q->limits.chunk_sectors) + unsigned int chunk_sectors = q->limits.chunk_sectors; + + if (!chunk_sectors) return q->limits.max_sectors; - return min(q->limits.max_sectors, (unsigned int)(q->limits.chunk_sectors - - (offset & (q->limits.chunk_sectors - 1)))); + if (likely(is_power_of_2(chunk_sectors))) + chunk_sectors -= offset & (chunk_sectors - 1); + else + chunk_sectors -= sector_div(offset, chunk_sectors); + + return min(q->limits.max_sectors, chunk_sectors); } static inline unsigned int blk_rq_get_max_sectors(struct request *rq, |