blk-mq: add blk_mq_requeue_request

This allows to requeue a request that has been accepted by ->queue_rq
earlier.  This is needed by the SCSI layer in various error conditions.

The existing internal blk_mq_requeue_request is renamed to
__blk_mq_requeue_request as it is a lower level building block for this
funtionality.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Christoph Hellwig 2014-04-16 09:44:57 +02:00 committed by Jens Axboe
parent 2f26855656
commit ed0791b2f8
2 changed files with 18 additions and 2 deletions

View File

@ -400,7 +400,7 @@ static void blk_mq_start_request(struct request *rq, bool last)
rq->cmd_flags |= REQ_END;
}
static void blk_mq_requeue_request(struct request *rq)
static void __blk_mq_requeue_request(struct request *rq)
{
struct request_queue *q = rq->q;
@ -413,6 +413,20 @@ static void blk_mq_requeue_request(struct request *rq)
rq->nr_phys_segments--;
}
void blk_mq_requeue_request(struct request *rq)
{
struct request_queue *q = rq->q;
__blk_mq_requeue_request(rq);
blk_clear_rq_complete(rq);
trace_block_rq_requeue(q, rq);
BUG_ON(blk_queued_rq(rq));
blk_mq_insert_request(rq, true, true, false);
}
EXPORT_SYMBOL(blk_mq_requeue_request);
struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag)
{
return tags->rqs[tag];
@ -602,7 +616,7 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
* time
*/
list_add(&rq->queuelist, &rq_list);
blk_mq_requeue_request(rq);
__blk_mq_requeue_request(rq);
break;
default:
pr_err("blk-mq: bad return on queue: %d\n", ret);

View File

@ -153,6 +153,8 @@ void blk_mq_free_single_hw_queue(struct blk_mq_hw_ctx *, unsigned int);
void blk_mq_end_io(struct request *rq, int error);
void __blk_mq_end_io(struct request *rq, int error);
void blk_mq_requeue_request(struct request *rq);
void blk_mq_complete_request(struct request *rq);
void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx);