nvme-pci: fix NULL req in completion handler

Currently, we use nvmeq->q_depth as the upper limit for a valid tag in
nvme_handle_cqe(), it is not correct. Because the available tag number
is recorded in tagset, which is not equal to nvmeq->q_depth.

The nvme driver registers interrupts for queues before initializing the
tagset, because it uses the number of successful request_irq() calls to
configure the tagset parameters. This allows a race condition with the
current tag validity check if the controller happens to produce an
interrupt with a corrupted CQE before the tagset is initialized.

Replace the driver's indirect tag check with the one already provided by
the block layer.

Signed-off-by: Xianting Tian <tian.xianting@h3c.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index d31e298..d286c26 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -940,13 +940,6 @@ static inline void nvme_handle_cqe(struct nvme_queue *nvmeq, u16 idx)
        struct nvme_completion *cqe = &nvmeq->cqes[idx];
        struct request *req;
 
-       if (unlikely(cqe->command_id >= nvmeq->q_depth)) {
-               dev_warn(nvmeq->dev->ctrl.device,
-                       "invalid id %d completed on queue %d\n",
-                       cqe->command_id, le16_to_cpu(cqe->sq_id));
-               return;
-       }
-
        /*
         * AEN requests are special as they don't time out and can
         * survive any kind of queue freeze and often don't respond to
@@ -960,6 +953,13 @@ static inline void nvme_handle_cqe(struct nvme_queue *nvmeq, u16 idx)
        }
 
        req = blk_mq_tag_to_rq(nvme_queue_tagset(nvmeq), cqe->command_id);
+       if (unlikely(!req)) {
+               dev_warn(nvmeq->dev->ctrl.device,
+                       "invalid id %d completed on queue %d\n",
+                       cqe->command_id, le16_to_cpu(cqe->sq_id));
+               return;
+       }
+
        trace_nvme_sq(req, cqe->sq_head, nvmeq->sq_tail);
        if (!nvme_try_complete_req(req, cqe->status, cqe->result))
                nvme_pci_complete_rq(req);