Re: [PATCH v4 01/11] blk-mq: fix direct issue
From: Bart Van Assche <hidden>
Date: 2017-06-05 21:25:33
On Mon, 2017-06-05 at 23:59 +0800, Ming Lei wrote:
quoted hunk ↗ jump to hunk
+static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, + struct request *rq, + blk_qc_t *cookie, bool may_sleep) { struct request_queue *q =3D rq->q; struct blk_mq_queue_data bd =3D { .rq =3D rq, .last =3D true, }; - struct blk_mq_hw_ctx *hctx; blk_qc_t new_cookie; int ret; + bool run_queue =3D true; + + if (blk_mq_hctx_stopped(hctx)) { + run_queue =3D false; + goto insert; + } =20 if (q->elevator) goto insert; =20 - if (!blk_mq_get_driver_tag(rq, &hctx, false)) + if (!blk_mq_get_driver_tag(rq, NULL, false)) goto insert; =20 new_cookie =3D request_to_qc_t(hctx, rq);@@ -1439,7 +1445,7 @@ static void __blk_mq_try_issue_directly(struct requ=
est *rq, blk_qc_t *cookie,
quoted hunk ↗ jump to hunk
=20 __blk_mq_requeue_request(rq); insert: - blk_mq_sched_insert_request(rq, false, true, false, may_sleep); + blk_mq_sched_insert_request(rq, false, run_queue, false, may_sleep); } =20 static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,@@ -1447,7 +1453,7 @@ static void blk_mq_try_issue_directly(struct blk_mq=
_hw_ctx *hctx,
quoted hunk ↗ jump to hunk
{ if (!(hctx->flags & BLK_MQ_F_BLOCKING)) { rcu_read_lock(); - __blk_mq_try_issue_directly(rq, cookie, false); + __blk_mq_try_issue_directly(hctx, rq, cookie, false); rcu_read_unlock(); } else { unsigned int srcu_idx;@@ -1455,7 +1461,7 @@ static void blk_mq_try_issue_directly(struct blk_mq=
_hw_ctx *hctx,
might_sleep(); =20 srcu_idx =3D srcu_read_lock(&hctx->queue_rq_srcu); - __blk_mq_try_issue_directly(rq, cookie, true); + __blk_mq_try_issue_directly(hctx, rq, cookie, true); srcu_read_unlock(&hctx->queue_rq_srcu, srcu_idx); } }
Hello Ming, It seems like you are assuming that the hardware queue of the rq argument passed to __blk_mq_try_issue_directly() matches the hctx argument? Sorry but I think that's an incorrect assumption. Please have a look at the following code in blk_mq_make_request(): if (same_queue_rq) blk_mq_try_issue_directly(data.hctx, same_queue_rq, &cookie); Bart.=