Commit a22c00be authored by Jens Axboe's avatar Jens Axboe
Browse files

block: assign correct tag before doing prefetch of request 



Ensure that current tag is correctly assigned before attempting
to prefetch the first cacheline of the request.

Fixes: 92aff191 ("block: prefetch request to be initialized")
Reported-and-tested-by: default avatar <syzbot+cd20829ac44b92bf6ed0@syzkaller.appspotmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ef1661ba

block/blk-mq.c

+1 −1
Original line number Diff line number Diff line
@@ -405,8 +405,8 @@ __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data, 
	for (i = 0; tag_mask; i++) {

		if (!(tag_mask & (1UL << i)))

			continue;

		prefetch(tags->static_rqs[tag]);

		tag = tag_offset + i;

		prefetch(tags->static_rqs[tag]);

		tag_mask &= ~(1UL << i);

		rq = blk_mq_rq_ctx_init(data, tags, tag, alloc_time_ns);

		rq_list_add(data->cached_rq, rq);