From: Matthew Wilcox <matthew.r.wilcox@intel.com>
Date: Wed, 16 Mar 2011 20:52:19 +0000 (-0400)
Subject: NVMe: Simplify queue lookup
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=9ecdc946212f7cd592986b2c519b470404caa6b8;p=linux-beck.git

NVMe: Simplify queue lookup

Fill in all the num_possible_cpus() entries with duplicate pointers.
This reduces the complexity of the frequently-called get_nvmeq(), as
well as avoiding a bug in it when there are fewer queues than CPUs.

Reported-by: Shane Michael Matthews <shane.matthews@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---

diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index 8d3c0b79ac2b..f94f1731478f 100644
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -221,12 +221,7 @@ static void cancel_cmdid_data(struct nvme_queue *nvmeq, int cmdid)
 
 static struct nvme_queue *get_nvmeq(struct nvme_ns *ns)
 {
-	int qid, cpu = get_cpu();
-	if (cpu < ns->dev->queue_count)
-		qid = cpu + 1;
-	else
-		qid = (cpu % rounddown_pow_of_two(ns->dev->queue_count)) + 1;
-	return ns->dev->queues[qid];
+	return ns->dev->queues[get_cpu() + 1];
 }
 
 static void put_nvmeq(struct nvme_queue *nvmeq)
@@ -1316,6 +1311,11 @@ static int __devinit nvme_setup_io_queues(struct nvme_dev *dev)
 		dev->queue_count++;
 	}
 
+	for (; i < num_possible_cpus(); i++) {
+		int target = i % rounddown_pow_of_two(dev->queue_count - 1);
+		dev->queues[i + 1] = dev->queues[target + 1];
+	}
+
 	return 0;
 }