net: add an helper to copy xps maps to the new dev_maps

This patch adds an helper, xps_copy_dev_maps, to copy maps from dev_maps
to new_dev_maps at a given index. The logic should be the same, with an
improved code readability and maintenance.

Signed-off-by: Antoine Tenart <atenart@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/dev.c b/net/core/dev.c
index af57e32..00f6b41 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2608,6 +2608,25 @@ static struct xps_map *expand_xps_map(struct xps_map *map, int attr_index,
        return new_map;
 }
 
+/* Copy xps maps at a given index */
+static void xps_copy_dev_maps(struct xps_dev_maps *dev_maps,
+                             struct xps_dev_maps *new_dev_maps, int index,
+                             int tc, bool skip_tc)
+{
+       int i, tci = index * dev_maps->num_tc;
+       struct xps_map *map;
+
+       /* copy maps belonging to foreign traffic classes */
+       for (i = 0; i < dev_maps->num_tc; i++, tci++) {
+               if (i == tc && skip_tc)
+                       continue;
+
+               /* fill in the new device map from the old device map */
+               map = xmap_dereference(dev_maps->attr_map[tci]);
+               RCU_INIT_POINTER(new_dev_maps->attr_map[tci], map);
+       }
+}
+
 /* Must be called under cpus_read_lock */
 int __netif_set_xps_queue(struct net_device *dev, const unsigned long *mask,
                          u16 index, enum xps_map_type type)
@@ -2694,23 +2713,16 @@ int __netif_set_xps_queue(struct net_device *dev, const unsigned long *mask,
        }
 
        for (j = 0; j < nr_ids; j++) {
-               /* copy maps belonging to foreign traffic classes */
-               for (i = tc, tci = j * num_tc; copy && i--; tci++) {
-                       /* fill in the new device map from the old device map */
-                       map = xmap_dereference(dev_maps->attr_map[tci]);
-                       RCU_INIT_POINTER(new_dev_maps->attr_map[tci], map);
-               }
+               bool skip_tc = false;
 
-               /* We need to explicitly update tci as prevous loop
-                * could break out early if dev_maps is NULL.
-                */
                tci = j * num_tc + tc;
-
                if (netif_attr_test_mask(j, mask, nr_ids) &&
                    netif_attr_test_online(j, online_mask, nr_ids)) {
                        /* add tx-queue to CPU/rx-queue maps */
                        int pos = 0;
 
+                       skip_tc = true;
+
                        map = xmap_dereference(new_dev_maps->attr_map[tci]);
                        while ((pos < map->len) && (map->queues[pos] != index))
                                pos++;
@@ -2725,18 +2737,11 @@ int __netif_set_xps_queue(struct net_device *dev, const unsigned long *mask,
                                        numa_node_id = -1;
                        }
 #endif
-               } else if (copy) {
-                       /* fill in the new device map from the old device map */
-                       map = xmap_dereference(dev_maps->attr_map[tci]);
-                       RCU_INIT_POINTER(new_dev_maps->attr_map[tci], map);
                }
 
-               /* copy maps belonging to foreign traffic classes */
-               for (i = num_tc - tc, tci++; copy && --i; tci++) {
-                       /* fill in the new device map from the old device map */
-                       map = xmap_dereference(dev_maps->attr_map[tci]);
-                       RCU_INIT_POINTER(new_dev_maps->attr_map[tci], map);
-               }
+               if (copy)
+                       xps_copy_dev_maps(dev_maps, new_dev_maps, j, tc,
+                                         skip_tc);
        }
 
        rcu_assign_pointer(dev->xps_maps[type], new_dev_maps);