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Subject[PATCH AUTOSEL 5.4 17/18] nvme-pci: fix NULL req in completion handler
Date
From: Xianting Tian <tian.xianting@h3c.com>

[ Upstream commit 50b7c24390a53c78de546215282fb52980f1d7b7 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/host/pci.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index a91433bdf5de4..fbfcded7a20d9 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -941,13 +941,6 @@ static inline void nvme_handle_cqe(struct nvme_queue *nvmeq, u16 idx)
volatile 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
@@ -962,6 +955,13 @@ 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);
nvme_end_request(req, cqe->status, cqe->result);
}
--
2.25.1
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