From: Ashok Vairavan <ashok.vairavan@oracle.com>
Date: Mon, 13 Mar 2017 01:43:54 +0000 (-0700)
Subject: Revert "nvme: avoid cqe corruption when update at the same time as read"
X-Git-Tag: v4.1.12-102.0.20170601_1400~209
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=59b2987ebeb0fa22118f23e9cfd36d0e8dcd9d37;p=users%2Fjedix%2Flinux-maple.git

Revert "nvme: avoid cqe corruption when update at the same time as read"

This reverts commit 4369f33dfdd50a5011922d45830e2b69ba4067ce.
---

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index cbe8ad7ff4328..3ee056b8aa29d 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -956,13 +956,6 @@ out:
 	return ret;
 }
 
-/* We read the CQE phase first to check if the rest of the entry is valid */
-static inline bool nvme_cqe_valid(struct nvme_queue *nvmeq, u16 head,
-        u16 phase)
-{
-        return (le16_to_cpu(nvmeq->cqes[head].status) & 1) == phase;
-}
-
 static int nvme_process_cq(struct nvme_queue *nvmeq)
 {
 	u16 head, phase;
@@ -970,10 +963,12 @@ static int nvme_process_cq(struct nvme_queue *nvmeq)
 	head = nvmeq->cq_head;
 	phase = nvmeq->cq_phase;
 
-	while (nvme_cqe_valid(nvmeq, head, phase)) {
+	for (;;) {
 		void *ctx;
 		nvme_completion_fn fn;
 		struct nvme_completion cqe = nvmeq->cqes[head];
+		if ((le16_to_cpu(cqe.status) & 1) != phase)
+			break;
 		nvmeq->sq_head = le16_to_cpu(cqe.sq_head);
 		if (++head == nvmeq->q_depth) {
 			head = 0;
@@ -1016,9 +1011,10 @@ static irqreturn_t nvme_irq(int irq, void *data)
 static irqreturn_t nvme_irq_check(int irq, void *data)
 {
 	struct nvme_queue *nvmeq = data;
-        if (nvme_cqe_valid(nvmeq, nvmeq->cq_head, nvmeq->cq_phase))
-                return IRQ_WAKE_THREAD;
-        return IRQ_NONE;
+	struct nvme_completion cqe = nvmeq->cqes[nvmeq->cq_head];
+	if ((le16_to_cpu(cqe.status) & 1) != nvmeq->cq_phase)
+		return IRQ_NONE;
+	return IRQ_WAKE_THREAD;
 }
 
 /*