blk-mq: add timer in blk_mq_start_request

This way will become consistent with non-mq case, also avoid to update rq->deadline twice for mq. The comment said: "We do this early, to ensure we are on the right CPU.", but no percpu stuff is used in blk_add_timer(), so it isn't necessary. Even when inserting from plug list, there is no such guarantee at all. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>

blk-mq: add timer in blk_mq_start_request
This way will become consistent with non-mq case, also avoid to update rq->deadline twice for mq. The comment said: "We do this early, to ensure we are on the right CPU.", but no percpu stuff is used in blk_add_timer(), so it isn't necessary. Even when inserting from plug list, there is no such guarantee at all. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Ming Lei · Jens Axboe
1 parent 3ee3237239
Showing 1 changed file with 1 additions and 16 deletions Side-by-side Diff
block/blk-mq.c
@@ -411,16 +411,7 @@
 	if (unlikely(blk_bidi_rq(rq)))
 		rq->next_rq->resid_len = blk_rq_bytes(rq->next_rq);
  
-	/*
-	 * Just mark start time and set the started bit. Due to memory
-	 * ordering, we know we'll see the correct deadline as long as
-	 * REQ_ATOMIC_STARTED is seen. Use the default queue timeout,
-	 * unless one has been set in the request.
-	 */
-	if (!rq->timeout)
-		rq->deadline = jiffies + q->rq_timeout;
-	else
-		rq->deadline = jiffies + rq->timeout;
+	blk_add_timer(rq);
  
 	/*
 	 * Mark us as started and clear complete. Complete might have been
@@ -972,11 +963,6 @@
 		list_add_tail(&rq->queuelist, &ctx->rq_list);
  
 	blk_mq_hctx_mark_pending(hctx, ctx);
-
-	/*
-	 * We do this early, to ensure we are on the right CPU.
-	 */
-	blk_add_timer(rq);
 }
  
 void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue,
@@ -1219,7 +1205,6 @@
  
 		blk_mq_bio_to_request(rq, bio);
 		blk_mq_start_request(rq, true);
-		blk_add_timer(rq);
  
 		/*
 		 * For OK queue, we are done. For error, kill it. Any other
...	...	@@ -411,16 +411,7 @@
411	411	if (unlikely(blk_bidi_rq(rq)))
412	412	rq->next_rq->resid_len = blk_rq_bytes(rq->next_rq);
413	413
414		- /*
415		- * Just mark start time and set the started bit. Due to memory
416		- * ordering, we know we'll see the correct deadline as long as
417		- * REQ_ATOMIC_STARTED is seen. Use the default queue timeout,
418		- * unless one has been set in the request.
419		- */
420		- if (!rq->timeout)
421		- rq->deadline = jiffies + q->rq_timeout;
422		- else
423		- rq->deadline = jiffies + rq->timeout;
	414	+ blk_add_timer(rq);
424	415
425	416	/*
426	417	* Mark us as started and clear complete. Complete might have been
...	...	@@ -972,11 +963,6 @@
972	963	list_add_tail(&rq->queuelist, &ctx->rq_list);
973	964
974	965	blk_mq_hctx_mark_pending(hctx, ctx);
975		-
976		- /*
977		- * We do this early, to ensure we are on the right CPU.
978		- */
979		- blk_add_timer(rq);
980	966	}
981	967
982	968	void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue,
...	...	@@ -1219,7 +1205,6 @@
1219	1205
1220	1206	blk_mq_bio_to_request(rq, bio);
1221	1207	blk_mq_start_request(rq, true);
1222		- blk_add_timer(rq);
1223	1208
1224	1209	/*
1225	1210	* For OK queue, we are done. For error, kill it. Any other