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block: assign correct tag before doing prefetch of request

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

Fixes: 92aff191cc ("block: prefetch request to be initialized")
Reported-and-tested-by: syzbot+cd20829ac44b92bf6ed0@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2021-11-01 06:56:09 -06:00
parent ef1661ba6d
commit a22c00be90
1 changed files with 1 additions and 1 deletions
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2
block/blk-mq.c
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@ -405,8 +405,8 @@ __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data,
for (i = 0; tag_mask; i++) { for (i = 0; tag_mask; i++) {
if (!(tag_mask & (1UL << i))) if (!(tag_mask & (1UL << i)))
continue; continue;
prefetch(tags->static_rqs[tag]);
tag = tag_offset + i; tag = tag_offset + i;
prefetch(tags->static_rqs[tag]);
tag_mask &= ~(1UL << i); tag_mask &= ~(1UL << i);
rq = blk_mq_rq_ctx_init(data, tags, tag, alloc_time_ns); rq = blk_mq_rq_ctx_init(data, tags, tag, alloc_time_ns);
rq_list_add(data->cached_rq, rq); rq_list_add(data->cached_rq, rq);