net: Add support for XPS with QoS via traffic classes

This patch adds support for setting and using XPS when QoS via traffic
classes is enabled.  With this change we will factor in the priority and
traffic class mapping of the packet and use that information to correctly
select the queue.

This allows us to define a set of queues for a given traffic class via
mqprio and then configure the XPS mapping for those queues so that the
traffic flows can avoid head-of-line blocking between the individual CPUs
if so desired.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 11 deletions

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 38bd9b933195..b0c04cf4851d 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1210,29 +1210,38 @@ static ssize_t show_xps_map(struct netdev_queue *queue,
 			    struct netdev_queue_attribute *attribute, char *buf)
 {
 	struct net_device *dev = queue->dev;
+	int cpu, len, num_tc = 1, tc = 0;
 	struct xps_dev_maps *dev_maps;
 	cpumask_var_t mask;
 	unsigned long index;
-	int i, len;
 
 	if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
 		return -ENOMEM;
 
 	index = get_netdev_queue_index(queue);
 
+	if (dev->num_tc) {
+		num_tc = dev->num_tc;
+		tc = netdev_txq_to_tc(dev, index);
+		if (tc < 0)
+			return -EINVAL;
+	}
+
 	rcu_read_lock();
 	dev_maps = rcu_dereference(dev->xps_maps);
 	if (dev_maps) {
-		for_each_possible_cpu(i) {
-			struct xps_map *map =
-			    rcu_dereference(dev_maps->cpu_map[i]);
-			if (map) {
-				int j;
-				for (j = 0; j < map->len; j++) {
-					if (map->queues[j] == index) {
-						cpumask_set_cpu(i, mask);
-						break;
-					}
+		for_each_possible_cpu(cpu) {
+			int i, tci = cpu * num_tc + tc;
+			struct xps_map *map;
+
+			map = rcu_dereference(dev_maps->cpu_map[tci]);
+			if (!map)
+				continue;
+
+			for (i = map->len; i--;) {
+				if (map->queues[i] == index) {
+					cpumask_set_cpu(cpu, mask);
+					break;
 				}
 			}
 		}