[PATCH] nvme-rdma: avoid repeated request completion for concurrent nvme_rdma_timeout

[Chao Leng]

A crash happens when inject completing request long time(nearly 30s).
Each name space has a request queue, when inject completing request long
time, multi request queues may has time out requests at the same time,
nvme_rdma_timeout will execute concurrently. Multi requests in different
request queues may be queued in the same rdma queue, multi
nvme_rdma_timeout may call nvme_rdma_stop_queue at the same time.
The first nvme_rdma_timeout will clear NVME_RDMA_Q_LIVE and continue
stopping the rdma queue(drain qp), but the others check NVME_RDMA_Q_LIVE
is already cleared, and then directly complete the requests, but the
rdma queue may be not stopped and the request may be already completed
in qp and wait treated, the request will be repeated completed.
Add a multex lock to serialize nvme_rdma_stop_queue.

Signed-off-by: Chao Leng <lengchao at huawei.com>
---
 drivers/nvme/host/rdma.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index df9f6f4549f1..d5c66e3eeb4a 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -97,6 +97,7 @@ struct nvme_rdma_queue {
 	struct completion	cm_done;
 	bool			pi_support;
 	int			cq_size;
+	struct mutex		queue_lock;
 };
 
 struct nvme_rdma_ctrl {
@@ -579,6 +580,7 @@ static int nvme_rdma_alloc_queue(struct nvme_rdma_ctrl *ctrl,
 	int ret;
 
 	queue = &ctrl->queues[idx];
+	mutex_init(&queue->queue_lock);
 	queue->ctrl = ctrl;
 	if (idx && ctrl->ctrl.max_integrity_segments)
 		queue->pi_support = true;
@@ -598,7 +600,8 @@ static int nvme_rdma_alloc_queue(struct nvme_rdma_ctrl *ctrl,
 	if (IS_ERR(queue->cm_id)) {
 		dev_info(ctrl->ctrl.device,
 			"failed to create CM ID: %ld\n", PTR_ERR(queue->cm_id));
-		return PTR_ERR(queue->cm_id);
+		ret = PTR_ERR(queue->cm_id);
+		goto out_destroy_mutex;
 	}
 
 	if (ctrl->ctrl.opts->mask & NVMF_OPT_HOST_TRADDR)
@@ -628,6 +631,8 @@ static int nvme_rdma_alloc_queue(struct nvme_rdma_ctrl *ctrl,
 out_destroy_cm_id:
 	rdma_destroy_id(queue->cm_id);
 	nvme_rdma_destroy_queue_ib(queue);
+out_destroy_mutex:
+	mutex_destroy(&queue->queue_lock);
 	return ret;
 }
 
@@ -639,9 +644,10 @@ static void __nvme_rdma_stop_queue(struct nvme_rdma_queue *queue)
 
 static void nvme_rdma_stop_queue(struct nvme_rdma_queue *queue)
 {
-	if (!test_and_clear_bit(NVME_RDMA_Q_LIVE, &queue->flags))
-		return;
-	__nvme_rdma_stop_queue(queue);
+	mutex_lock(&queue->queue_lock);
+	if (test_and_clear_bit(NVME_RDMA_Q_LIVE, &queue->flags))
+		__nvme_rdma_stop_queue(queue);
+	mutex_unlock(&queue->queue_lock);
 }
 
 static void nvme_rdma_free_queue(struct nvme_rdma_queue *queue)
@@ -649,6 +655,7 @@ static void nvme_rdma_free_queue(struct nvme_rdma_queue *queue)
 	if (!test_and_clear_bit(NVME_RDMA_Q_ALLOCATED, &queue->flags))
 		return;
 
+	mutex_destroy(&queue->queue_lock);
 	nvme_rdma_destroy_queue_ib(queue);
 	rdma_destroy_id(queue->cm_id);
 }
-- 
2.16.4