IO logical block size is one fundamental queue limit, and every IO has to be aligned with logical block size because our bio split can't deal with unaligned bio.

The check has to be done with queue usage counter grabbed because device reconfiguration may change logical block size, and we can prevent the reconfiguration from happening by holding queue usage counter.

logical_block_size stays in the 1st cache line of queue_limits, and this cache line is always fetched in fast path via bio_may_exceed_limits(), so IO perf won't be affected by this check.

Cc: Yi Zhang yi.zhang@redhat.com Cc: Christoph Hellwig hch@infradead.org Cc: Ye Bin yebin10@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Ming Lei ming.lei@redhat.com --- V2: - cover any zero sized bio which .bi_sector needs to be initialized too

block/blk-mq.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c index 3b4df8e5ac9e..d161682ecd20 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2914,6 +2914,17 @@ static void blk_mq_use_cached_rq(struct request *rq, struct blk_plug *plug, INIT_LIST_HEAD(&rq->queuelist); }

+static bool bio_unaligned(const struct bio *bio, struct request_queue *q) +{ + unsigned int bs_mask = queue_logical_block_size(q) - 1; + + /* .bi_sector of any zero sized bio need to be initialized */ + if ((bio->bi_iter.bi_size & bs_mask) || + ((bio->bi_iter.bi_sector << SECTOR_SHIFT) & bs_mask)) + return true; + return false; +} + /** * blk_mq_submit_bio - Create and send a request to block device. * @bio: Bio pointer. @@ -2966,6 +2977,15 @@ void blk_mq_submit_bio(struct bio *bio) return; }

+ /* + * Device reconfiguration may change logical block size, so alignment + * check has to be done with queue usage counter held + */ + if (unlikely(bio_unaligned(bio, q))) { + bio_io_error(bio); + goto queue_exit; + } + if (unlikely(bio_may_exceed_limits(bio, &q->limits))) { bio = __bio_split_to_limits(bio, &q->limits, &nr_segs); if (!bio)