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| author | Keith Busch <kbusch@kernel.org> | 2020-04-28 16:21:56 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-05-10 00:18:36 +0200 |
| commit | 74943d45eef4db64b1e5c9f7ad1d018576e113c5 (patch) | |
| tree | 1a0d4c8bc6d51ede2b4d4c66f6198b847bc537de | |
| parent | nvme: flush scan work on passthrough commands (diff) | |
| download | linux-74943d45eef4db64b1e5c9f7ad1d018576e113c5.tar.xz linux-74943d45eef4db64b1e5c9f7ad1d018576e113c5.zip | |
nvme-pci: remove volatile cqes
The completion queue entry is not volatile once the phase is confirmed.
Remove the volatile keywords and check the phase using the appropriate
READ_ONCE() accessor, allowing the compiler to optimize the remaining
completion path.
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | drivers/nvme/host/pci.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index e13c370de830..e95c7465c7bd 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -166,7 +166,7 @@ struct nvme_queue { void *sq_cmds; /* only used for poll queues: */ spinlock_t cq_poll_lock ____cacheline_aligned_in_smp; - volatile struct nvme_completion *cqes; + struct nvme_completion *cqes; dma_addr_t sq_dma_addr; dma_addr_t cq_dma_addr; u32 __iomem *q_db; @@ -922,8 +922,9 @@ static void nvme_pci_complete_rq(struct request *req) /* We read the CQE phase first to check if the rest of the entry is valid */ static inline bool nvme_cqe_pending(struct nvme_queue *nvmeq) { - return (le16_to_cpu(nvmeq->cqes[nvmeq->cq_head].status) & 1) == - nvmeq->cq_phase; + struct nvme_completion *hcqe = &nvmeq->cqes[nvmeq->cq_head]; + + return (le16_to_cpu(READ_ONCE(hcqe->status)) & 1) == nvmeq->cq_phase; } static inline void nvme_ring_cq_doorbell(struct nvme_queue *nvmeq) @@ -944,7 +945,7 @@ static inline struct blk_mq_tags *nvme_queue_tagset(struct nvme_queue *nvmeq) static inline void nvme_handle_cqe(struct nvme_queue *nvmeq, u16 idx) { - volatile struct nvme_completion *cqe = &nvmeq->cqes[idx]; + struct nvme_completion *cqe = &nvmeq->cqes[idx]; struct request *req; if (unlikely(cqe->command_id >= nvmeq->q_depth)) { |