From 9c1d97a24766dd9fd6dc72ae86fa6f74684b59bc Mon Sep 17 00:00:00 2001
From: Jim Harris <james.r.harris@intel.com>
Date: Thu, 14 Dec 2017 17:24:51 -0700
Subject: [PATCH] nvme: add checks for sq_head

Signed-off-by: Jim Harris <james.r.harris@intel.com>
Change-Id: I8519a4b68db44cb8fe6dd251a52bf0f1dca73c32

Reviewed-on: https://review.gerrithub.io/391890
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>
---
 lib/nvme/nvme_pcie.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/nvme/nvme_pcie.c b/lib/nvme/nvme_pcie.c
index 37521f3e0..de6bef634 100644
--- a/lib/nvme/nvme_pcie.c
+++ b/lib/nvme/nvme_pcie.c
@@ -160,6 +160,7 @@ struct nvme_pcie_qpair {
 
 	uint16_t sq_tail;
 	uint16_t cq_head;
+	uint16_t sq_head;
 
 	uint8_t phase;
 
@@ -1096,6 +1097,10 @@ nvme_pcie_qpair_submit_tracker(struct spdk_nvme_qpair *qpair, struct nvme_tracke
 		pqpair->sq_tail = 0;
 	}
 
+	if (pqpair->sq_tail == pqpair->sq_head) {
+		SPDK_ERRLOG("sq_tail is passing sq_head!\n");
+	}
+
 	spdk_wmb();
 	g_thread_mmio_ctrlr = pctrlr;
 	if (spdk_likely(nvme_pcie_qpair_update_mmio_required(qpair,
@@ -1981,6 +1986,7 @@ nvme_pcie_qpair_process_completions(struct spdk_nvme_qpair *qpair, uint32_t max_
 #endif
 
 		tr = &pqpair->tr[cpl->cid];
+		pqpair->sq_head = cpl->sqhd;
 
 		if (tr->active) {
 			nvme_pcie_qpair_complete_tracker(qpair, tr, cpl, true);