On 2020/09/12 6:53, Mike Snitzer wrote: > It is possible for a block device to use a non power-of-2 for chunk > size which results in a full-stripe size that is also 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. > > Signed-off-by: Mike Snitzer <[email protected]> > --- > block/blk-settings.c | 10 ++++------ > 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 b09642d5f15e..e40a162cc946 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 453a3d735d66..e72bcce22143 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -1059,11 +1059,17 @@ 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 (is_power_of_2(chunk_sectors)) > + chunk_sectors -= (offset & (chunk_sectors - 1));
I do not think you need the outer parenthesis here. > + 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, > -- Damien Le Moal Western Digital Research -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
