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From: Jianchao Wang <jianchao.w.wang@oracle.com>
To: axboe@kernel.dk
Cc: ming.lei@redhat.com, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH V6 2/5] blk-mq: fix issue directly case when q is stopped or quiesced
Date: Tue, 13 Nov 2018 17:56:53 +0800	[thread overview]
Message-ID: <1542103016-21037-3-git-send-email-jianchao.w.wang@oracle.com> (raw)
In-Reply-To: <1542103016-21037-1-git-send-email-jianchao.w.wang@oracle.com>

When try to issue request directly, if the queue is stopped or
quiesced, 'bypass' will be ignored and return BLK_STS_OK to caller
to avoid it dispatch request again. Then the request will be
inserted with blk_mq_sched_insert_request. This is not correct
for dm-rq case where we should avoid to pass through the underlying
path's io scheduler.

To fix it, use blk_mq_request_bypass_insert to insert the request
to hctx->dispatch when we cannot pass through io scheduler but have
to insert.

Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
---
 block/blk-mq.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 14b4d06..11c52bb 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1772,7 +1772,7 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
 						bool bypass)
 {
 	struct request_queue *q = rq->q;
-	bool run_queue = true;
+	bool run_queue = true, force = false;
 	blk_status_t ret = BLK_STS_RESOURCE;
 	int srcu_idx;
 
@@ -1786,7 +1786,7 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
 	 */
 	if (unlikely(blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q))) {
 		run_queue = false;
-		bypass = false;
+		force = true;
 		goto out_unlock;
 	}
 
@@ -1817,6 +1817,9 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
 		if (!bypass) {
 			blk_mq_sched_insert_request(rq, false, run_queue, false);
 			ret = BLK_STS_OK;
+		} else if (force) {
+			blk_mq_request_bypass_insert(rq, run_queue);
+			ret = BLK_STS_OK;
 		}
 		break;
 	default:
-- 
2.7.4


  parent reply	other threads:[~2018-11-13  9:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-13  9:56 [PATCH V6 0/5] blk-mq: refactor and fix on issue request directly Jianchao Wang
2018-11-13  9:56 ` [PATCH V6 1/5] blk-mq: refactor the code of " Jianchao Wang
2018-11-13  9:56 ` Jianchao Wang [this message]
2018-11-13  9:56 ` [PATCH V6 3/5] blk-mq: ensure hctx to be ran on mapped cpu when issue directly Jianchao Wang
2018-11-13 13:44   ` Jens Axboe
2018-11-14  2:15     ` jianchao.wang
2018-11-14  3:02       ` Ming Lei
2018-11-14  3:38         ` jianchao.wang
2018-11-13  9:56 ` [PATCH V6 4/5] blk-mq: issue directly with bypass 'false' in blk_mq_sched_insert_requests Jianchao Wang
2018-11-13  9:56 ` [PATCH V6 5/5] blk-mq: replace and kill blk_mq_request_issue_directly Jianchao Wang

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