[PATCH 24/39] blk-mq: add blk_mq_requeue_request

[Christoph Hellwig]

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 <h...@lst.de>
---
 block/blk-mq.c         |   18 ++++++++++++++++--
 include/linux/blk-mq.h |    2 ++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index c7e723e..9e13761 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -380,7 +380,7 @@ 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;
 
@@ -393,6 +393,20 @@ static void blk_mq_requeue_request(struct request *rq)
                rq->nr_phys_segments--;
 }
 
+/* XXX: misnamed, only unpreps but leaves the actual requeue to the caller. */
+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));
+}
+EXPORT_SYMBOL(blk_mq_requeue_request);
+
 struct blk_mq_timeout_data {
        struct blk_mq_hw_ctx *hctx;
        unsigned long *next;
@@ -573,7 +587,7 @@ 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);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index cac10e1..6325a24 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -148,6 +148,8 @@ static inline void blk_mq_end_io(struct request *rq, int 
error)
        BUG_ON(!done);
 }
 
+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);
-- 
1.7.10.4


--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html