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path: root/drivers/nvme/host/pci.c
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Diffstat (limited to 'drivers/nvme/host/pci.c')
-rw-r--r--drivers/nvme/host/pci.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 4e79e412b276..3726dc780d15 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -973,9 +973,13 @@ static inline void nvme_handle_cqe(struct nvme_queue *nvmeq, u16 idx)
static inline void nvme_update_cq_head(struct nvme_queue *nvmeq)
{
- if (++nvmeq->cq_head == nvmeq->q_depth) {
+ u16 tmp = nvmeq->cq_head + 1;
+
+ if (tmp == nvmeq->q_depth) {
nvmeq->cq_head = 0;
nvmeq->cq_phase ^= 1;
+ } else {
+ nvmeq->cq_head = tmp;
}
}
@@ -985,6 +989,11 @@ static inline int nvme_process_cq(struct nvme_queue *nvmeq)
while (nvme_cqe_pending(nvmeq)) {
found++;
+ /*
+ * load-load control dependency between phase and the rest of
+ * the cqe requires a full read memory barrier
+ */
+ dma_rmb();
nvme_handle_cqe(nvmeq, nvmeq->cq_head);
nvme_update_cq_head(nvmeq);
}