From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: [PATCH v2 2/4] block: allow 'chunk_sectors' to be non-power-of-2 Date: Tue, 15 Sep 2020 13:23:55 -0400 Message-ID: <20200915172357.83215-3-snitzer@redhat.com> References: <20200915172357.83215-1-snitzer@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200915172357.83215-1-snitzer@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Jens Axboe Cc: linux-block@vger.kernel.org, dm-devel@redhat.com, Vijayendra Suman , Ming Lei List-Id: dm-devel.ids 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 Reviewed-by: Ming Lei --- 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 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 bb5636cc17b9..bbfbda33e993 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); + 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, -- 2.15.0