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| author | Christoph Hellwig <hch@lst.de> | 2014-09-13 16:40:09 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-09-22 12:00:07 -0600 |
| commit | e2490073cd7c3d6f6ef6e029a208edd4d38efac4 (patch) | |
| tree | 48465e67b335f6d696d698641365b4a4d1e89d32 /block | |
| parent | bf57229745f849e500ba69ff91e35bc8160a7373 (diff) | |
| download | linux-0-day-e2490073cd7c3d6f6ef6e029a208edd4d38efac4.tar.gz linux-0-day-e2490073cd7c3d6f6ef6e029a208edd4d38efac4.tar.xz | |
blk-mq: call blk_mq_start_request from ->queue_rq
When we call blk_mq_start_request from the core blk-mq code before calling into
->queue_rq there is a racy window where the timeout handler can hit before we've
fully set up the driver specific part of the command.
Move the call to blk_mq_start_request into the driver so the driver can start
the request only once it is fully set up.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-mq.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index 32b4797f41862..141f2e06803a2 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -384,7 +384,7 @@ void blk_mq_complete_request(struct request *rq) } EXPORT_SYMBOL(blk_mq_complete_request); -static void blk_mq_start_request(struct request *rq) +void blk_mq_start_request(struct request *rq) { struct request_queue *q = rq->q; @@ -422,16 +422,18 @@ static void blk_mq_start_request(struct request *rq) rq->nr_phys_segments++; } } +EXPORT_SYMBOL(blk_mq_start_request); static void __blk_mq_requeue_request(struct request *rq) { struct request_queue *q = rq->q; trace_block_rq_requeue(q, rq); - clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags); - if (q->dma_drain_size && blk_rq_bytes(rq)) - rq->nr_phys_segments--; + if (test_and_clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) { + if (q->dma_drain_size && blk_rq_bytes(rq)) + rq->nr_phys_segments--; + } } void blk_mq_requeue_request(struct request *rq) @@ -743,8 +745,6 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) rq = list_first_entry(&rq_list, struct request, queuelist); list_del_init(&rq->queuelist); - blk_mq_start_request(rq); - ret = q->mq_ops->queue_rq(hctx, rq, list_empty(&rq_list)); switch (ret) { case BLK_MQ_RQ_QUEUE_OK: @@ -1186,7 +1186,6 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio) int ret; blk_mq_bio_to_request(rq, bio); - blk_mq_start_request(rq); /* * For OK queue, we are done. For error, kill it. Any other |