From: Ming Lei <ming.lei@redhat.com>
Date: Thu, 20 Jun 2024 03:06:31 +0000 (+0800)
Subject: block: check bio alignment in blk_mq_submit_bio
X-Git-Tag: v6.11-rc1~80^2~26
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0676c434a99be42f3bacca4adfd27df65edbf903;p=thirdparty%2Flinux.git

block: check bio alignment in blk_mq_submit_bio

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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240620030631.3114026-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 47fe9d19b8f10..fec2dea5c6e88 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2909,6 +2909,17 @@ 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.
@@ -2961,6 +2972,15 @@ 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)