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From: Bart Van Assche <bart.vanassche@sandisk.com>
To: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@lst.de>,
	James Bottomley <jejb@linux.vnet.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Mike Snitzer <snitzer@redhat.com>,
	Doug Ledford <dledford@redhat.com>,
	Keith Busch <keith.busch@intel.com>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
Subject: [PATCH 9/9] [RFC] nvme: Fix a race condition
Date: Mon, 26 Sep 2016 11:28:59 -0700	[thread overview]
Message-ID: <9c372b04-a194-58c4-a64f-b155b52a5244@sandisk.com> (raw)
In-Reply-To: <7948dbb8-6333-dc62-2673-4da35b4dfdbc@sandisk.com>

Avoid that nvme_queue_rq() is still running when nvme_stop_queues()
returns. Untested.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
---
 drivers/nvme/host/core.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 057f1fa..6e2bf6a 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -201,13 +201,9 @@ fail:
 
 void nvme_requeue_req(struct request *req)
 {
-	unsigned long flags;
-
 	blk_mq_requeue_request(req);
-	spin_lock_irqsave(req->q->queue_lock, flags);
-	if (!blk_mq_queue_stopped(req->q))
-		blk_mq_kick_requeue_list(req->q);
-	spin_unlock_irqrestore(req->q->queue_lock, flags);
+	WARN_ON_ONCE(blk_mq_queue_stopped(req->q));
+	blk_mq_kick_requeue_list(req->q);
 }
 EXPORT_SYMBOL_GPL(nvme_requeue_req);
 
@@ -2079,11 +2075,15 @@ EXPORT_SYMBOL_GPL(nvme_kill_queues);
 void nvme_stop_queues(struct nvme_ctrl *ctrl)
 {
 	struct nvme_ns *ns;
+	struct request_queue *q;
 
 	mutex_lock(&ctrl->namespaces_mutex);
 	list_for_each_entry(ns, &ctrl->namespaces, list) {
-		blk_mq_cancel_requeue_work(ns->queue);
-		blk_mq_stop_hw_queues(ns->queue);
+		q = ns->queue;
+		blk_quiesce_queue(q);
+		blk_mq_cancel_requeue_work(q);
+		blk_mq_stop_hw_queues(q);
+		blk_resume_queue(q);
 	}
 	mutex_unlock(&ctrl->namespaces_mutex);
 }
-- 
2.10.0


WARNING: multiple messages have this Message-ID (diff)
From: bart.vanassche@sandisk.com (Bart Van Assche)
Subject: [PATCH 9/9] [RFC] nvme: Fix a race condition
Date: Mon, 26 Sep 2016 11:28:59 -0700	[thread overview]
Message-ID: <9c372b04-a194-58c4-a64f-b155b52a5244@sandisk.com> (raw)
In-Reply-To: <7948dbb8-6333-dc62-2673-4da35b4dfdbc@sandisk.com>

Avoid that nvme_queue_rq() is still running when nvme_stop_queues()
returns. Untested.

Signed-off-by: Bart Van Assche <bart.vanassche at sandisk.com>
Cc: Keith Busch <keith.busch at intel.com>
Cc: Christoph Hellwig <hch at lst.de>
Cc: Sagi Grimberg <sagi at grimberg.me>
---
 drivers/nvme/host/core.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 057f1fa..6e2bf6a 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -201,13 +201,9 @@ fail:
 
 void nvme_requeue_req(struct request *req)
 {
-	unsigned long flags;
-
 	blk_mq_requeue_request(req);
-	spin_lock_irqsave(req->q->queue_lock, flags);
-	if (!blk_mq_queue_stopped(req->q))
-		blk_mq_kick_requeue_list(req->q);
-	spin_unlock_irqrestore(req->q->queue_lock, flags);
+	WARN_ON_ONCE(blk_mq_queue_stopped(req->q));
+	blk_mq_kick_requeue_list(req->q);
 }
 EXPORT_SYMBOL_GPL(nvme_requeue_req);
 
@@ -2079,11 +2075,15 @@ EXPORT_SYMBOL_GPL(nvme_kill_queues);
 void nvme_stop_queues(struct nvme_ctrl *ctrl)
 {
 	struct nvme_ns *ns;
+	struct request_queue *q;
 
 	mutex_lock(&ctrl->namespaces_mutex);
 	list_for_each_entry(ns, &ctrl->namespaces, list) {
-		blk_mq_cancel_requeue_work(ns->queue);
-		blk_mq_stop_hw_queues(ns->queue);
+		q = ns->queue;
+		blk_quiesce_queue(q);
+		blk_mq_cancel_requeue_work(q);
+		blk_mq_stop_hw_queues(q);
+		blk_resume_queue(q);
 	}
 	mutex_unlock(&ctrl->namespaces_mutex);
 }
-- 
2.10.0

  parent reply	other threads:[~2016-09-26 18:29 UTC|newest]

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-26 18:25 [PATCH 0/9] Introduce blk_quiesce_queue() and blk_resume_queue() Bart Van Assche
2016-09-26 18:25 ` Bart Van Assche
2016-09-26 18:26 ` [PATCH 1/9] blk-mq: Introduce blk_mq_queue_stopped() Bart Van Assche
2016-09-26 18:26   ` Bart Van Assche
2016-09-26 18:26   ` Bart Van Assche
2016-09-27  6:20   ` Hannes Reinecke
2016-09-27  6:20     ` Hannes Reinecke
2016-09-27  7:38   ` Johannes Thumshirn
2016-09-27  7:38     ` Johannes Thumshirn
2016-09-27  7:38     ` Johannes Thumshirn
2016-09-26 18:26 ` [PATCH 2/9] dm: Fix a race condition related to stopping and starting queues Bart Van Assche
2016-09-26 18:26   ` Bart Van Assche
2016-09-27  6:21   ` Hannes Reinecke
2016-09-27  6:21     ` Hannes Reinecke
2016-09-27  6:21     ` Hannes Reinecke
2016-09-27  7:47   ` Johannes Thumshirn
2016-09-27  7:47     ` Johannes Thumshirn
2016-09-27  7:47     ` Johannes Thumshirn
2016-09-26 18:27 ` [PATCH 3/9] [RFC] nvme: Use BLK_MQ_S_STOPPED instead of QUEUE_FLAG_STOPPED in blk-mq code Bart Van Assche
2016-09-26 18:27   ` Bart Van Assche
2016-09-26 18:27   ` Bart Van Assche
2016-09-26 18:27 ` [PATCH 4/9] block: Move blk_freeze_queue() and blk_unfreeze_queue() code Bart Van Assche
2016-09-26 18:27   ` Bart Van Assche
2016-09-27  6:26   ` Hannes Reinecke
2016-09-27  6:26     ` Hannes Reinecke
2016-09-27  6:26     ` Hannes Reinecke
2016-09-27  7:52     ` Johannes Thumshirn
2016-09-27  7:52       ` Johannes Thumshirn
2016-09-27  7:52       ` Johannes Thumshirn
2016-09-26 18:27 ` [PATCH 5/9] block: Extend blk_freeze_queue_start() to the non-blk-mq path Bart Van Assche
2016-09-26 18:27   ` Bart Van Assche
2016-09-26 18:27   ` Bart Van Assche
2016-09-27  7:50   ` Johannes Thumshirn
2016-09-27  7:50     ` Johannes Thumshirn
2016-09-27  7:50     ` Johannes Thumshirn
2016-09-27 13:22   ` Ming Lei
2016-09-27 13:22     ` Ming Lei
2016-09-27 14:42     ` Bart Van Assche
2016-09-27 14:42       ` Bart Van Assche
2016-09-27 14:42       ` Bart Van Assche
2016-09-27 15:55       ` Bart Van Assche
2016-09-27 15:55         ` Bart Van Assche
2016-09-27 15:55         ` Bart Van Assche
2016-09-26 18:28 ` [PATCH 6/9] block: Rename mq_freeze_wq and mq_freeze_depth Bart Van Assche
2016-09-26 18:28   ` Bart Van Assche
2016-09-27  7:51   ` Johannes Thumshirn
2016-09-27  7:51     ` Johannes Thumshirn
2016-09-27  7:51     ` Johannes Thumshirn
2016-09-26 18:28 ` [PATCH 7/9] blk-mq: Introduce blk_quiesce_queue() and blk_resume_queue() Bart Van Assche
2016-09-26 18:28   ` Bart Van Assche
2016-09-26 18:28 ` [PATCH 8/9] SRP transport: Port srp_wait_for_queuecommand() to scsi-mq Bart Van Assche
2016-09-26 18:28   ` Bart Van Assche
2016-09-26 18:28 ` Bart Van Assche [this message]
2016-09-26 18:28   ` [PATCH 9/9] [RFC] nvme: Fix a race condition Bart Van Assche
2016-09-27 16:31   ` Steve Wise
2016-09-27 16:31     ` Steve Wise
2016-09-27 16:31     ` Steve Wise
2016-09-27 16:43     ` Bart Van Assche
2016-09-27 16:43       ` Bart Van Assche
2016-09-27 16:43       ` Bart Van Assche
2016-09-27 16:56       ` James Bottomley
2016-09-27 16:56         ` James Bottomley
2016-09-27 17:09         ` Bart Van Assche
2016-09-27 17:09           ` Bart Van Assche
2016-09-27 17:09           ` Bart Van Assche
2016-09-28 14:23           ` Steve Wise
2016-09-28 14:23             ` Steve Wise
2016-09-28 14:23             ` Steve Wise
2016-09-27 16:56       ` Steve Wise
2016-09-27 16:56         ` Steve Wise
2016-09-27 16:56         ` Steve Wise
2016-09-26 18:33 ` [PATCH 0/9] Introduce blk_quiesce_queue() and blk_resume_queue() Mike Snitzer
2016-09-26 18:33   ` Mike Snitzer
2016-09-26 18:33   ` Mike Snitzer
2016-09-26 18:46   ` Bart Van Assche
2016-09-26 18:46     ` Bart Van Assche
2016-09-26 18:46     ` Bart Van Assche
2016-09-26 22:26   ` Bart Van Assche
2016-09-26 22:26     ` Bart Van Assche
2016-09-26 22:26     ` Bart Van Assche
2016-10-11 16:27 ` Laurence Oberman
2016-10-11 16:27   ` Laurence Oberman

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