linux-kernel - [PATCH v2] NVMe: do not touch sq door bell if nvmeq has been suspended

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Date:	Tue,  2 Feb 2016 03:31:34 -0500
From:	Wenbo Wang <mail_weber_wang@....com>
To:	axboe@...com, keith.busch@...el.com
Cc:	linux-kernel@...r.kernel.org, Wenbo Wang <mail_weber_wang@....com>
Subject: [PATCH v2] NVMe: do not touch sq door bell if nvmeq has been suspended

If __nvme_submit_cmd races with nvme_dev_disable, nvmeq
could have been suspended and dev->bar could have been
unmapped. Do not touch sq door bell in this case.

Signed-off-by: Wenbo Wang <mail_weber_wang@....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 8b1a725..30795f6 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 == -1)) {
+		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);
-- 
1.8.3.1