On 10/11/16 09:46, Christoph Hellwig wrote:

On Wed, Sep 28, 2016 at 05:01:45PM -0700, Bart Van Assche wrote:

quoted

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

Signed-off-by: Bart Van Assche <redacted>
Cc: Keith Busch <redacted>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
---
 drivers/nvme/host/core.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index d791fba..98f1f29 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);

Can we just add a 'bool kick' argument to blk_mq_requeue_request and
move all this handling to the core?

Hello Christoph,

That sounds like a good idea to me. Thanks also for the other review 
comments you posted on this patch series. I will rework patch 6/7 such 
that the code for waiting is moved into the SCSI core.

Bart.