From: Matthew Wilcox <matthew.r.wilcox@intel.com>
Date: Thu, 24 Feb 2011 13:49:41 +0000 (-0500)
Subject: NVMe: Reduce maximum queue depth by 1
X-Git-Tag: firefly_0821_release~3680^2~2014^2~60
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e6d15f79f997a98b3a69abbc462fc9041cc1a7b4;p=firefly-linux-kernel-4.4.55.git

NVMe: Reduce maximum queue depth by 1

The spec says we're not allowed to completely fill the submission queue.
Solve this by reducing the number of allocatable cmdids by 1.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---

diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index 562d75a0fc50..45bfae1ebd50 100644
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -156,7 +156,7 @@ static struct nvme_cmd_info *nvme_cmd_info(struct nvme_queue *nvmeq)
 static int alloc_cmdid(struct nvme_queue *nvmeq, void *ctx, int handler,
 							unsigned timeout)
 {
-	int depth = nvmeq->q_depth;
+	int depth = nvmeq->q_depth - 1;
 	struct nvme_cmd_info *info = nvme_cmd_info(nvmeq);
 	int cmdid;