[PATCH for-4.5 07/13] NVMe: Requeue requests on suspended queues

[Wenbo Wang]

If adding synchronize_rcu and blk_sync_queue, I guess this is not needed.

-----Original Message-----
From: Keith Busch [mailto:keith.busch at intel.com] 
Sent: Thursday, February 11, 2016 2:17 AM
To: linux-nvme at lists.infradead.org; Jens Axboe
Cc: Christoph Hellwig; Sagi Grimberg; Wenbo Wang; Keith Busch
Subject: [PATCH for-4.5 07/13] NVMe: Requeue requests on suspended queues

It's possible a request may get to the driver after the nvme queue was disabled. This has the request requeue if that happens.

Note the request is still "started" by the driver, but requeuing will clear the start state for timeout handling.

Signed-off-by: Keith Busch <keith.busch at intel.com>
---
 drivers/nvme/host/pci.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 5bea054..f8bb781 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -678,6 +678,11 @@ static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
 	blk_mq_start_request(req);
 
 	spin_lock_irq(&nvmeq->q_lock);
+	if (unlikely(nvmeq->cq_vector < 0)) {
+		ret = BLK_MQ_RQ_QUEUE_BUSY;
+		spin_unlock_irq(&nvmeq->q_lock);
+		goto out;
+	}
 	__nvme_submit_cmd(nvmeq, &cmnd);
 	nvme_process_cq(nvmeq);
 	spin_unlock_irq(&nvmeq->q_lock);
--
2.6.2.307.g37023ba