net: create sysfs symlinks for neighbour devices

Also, remove the same functionality from bonding - it will be already done
for any device that links to its lower/upper neighbour.

The links will be created for dev's kobject, and will look like
lower_eth0 for lower device eth0 and upper_bridge0 for upper device
bridge0.

CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
CC: "David S. Miller" <davem@davemloft.net>
CC: Eric Dumazet <edumazet@google.com>
CC: Jiri Pirko <jiri@resnulli.us>
CC: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 34 insertions, 1 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index de443ee1b046..25ab6fe80da2 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4584,6 +4584,7 @@ static int __netdev_adjacent_dev_insert(struct net_device *dev,
                                         void *private, bool master)
 {
         struct netdev_adjacent *adj;
+        char linkname[IFNAMSIZ+7];
         int ret;
 
         adj = __netdev_find_adj(dev, adj_dev, dev_list);
@@ -4606,12 +4607,26 @@ static int __netdev_adjacent_dev_insert(struct net_device *dev,
         pr_debug("dev_hold for %s, because of link added from %s to %s\n",
                  adj_dev->name, dev->name, adj_dev->name);
 
+        if (dev_list == &dev->adj_list.lower) {
+                sprintf(linkname, "lower_%s", adj_dev->name);
+                ret = sysfs_create_link(&(dev->dev.kobj),
+                                        &(adj_dev->dev.kobj), linkname);
+                if (ret)
+                        goto free_adj;
+        } else if (dev_list == &dev->adj_list.upper) {
+                sprintf(linkname, "upper_%s", adj_dev->name);
+                ret = sysfs_create_link(&(dev->dev.kobj),
+                                        &(adj_dev->dev.kobj), linkname);
+                if (ret)
+                        goto free_adj;
+        }
+
         /* Ensure that master link is always the first item in list. */
         if (master) {
                 ret = sysfs_create_link(&(dev->dev.kobj),
                                         &(adj_dev->dev.kobj), "master");
                 if (ret)
-                        goto free_adj;
+                        goto remove_symlinks;
 
                 list_add_rcu(&adj->list, dev_list);
         } else {
@@ -4620,6 +4635,15 @@ static int __netdev_adjacent_dev_insert(struct net_device *dev,
 
         return 0;
 
+remove_symlinks:
+        if (dev_list == &dev->adj_list.lower) {
+                sprintf(linkname, "lower_%s", adj_dev->name);
+                sysfs_remove_link(&(dev->dev.kobj), linkname);
+        } else if (dev_list == &dev->adj_list.upper) {
+                sprintf(linkname, "upper_%s", adj_dev->name);
+                sysfs_remove_link(&(dev->dev.kobj), linkname);
+        }
+
 free_adj:
         kfree(adj);
 
@@ -4631,6 +4655,7 @@ void __netdev_adjacent_dev_remove(struct net_device *dev,
                                   struct list_head *dev_list)
 {
         struct netdev_adjacent *adj;
+        char linkname[IFNAMSIZ+7];
 
         adj = __netdev_find_adj(dev, adj_dev, dev_list);
 
@@ -4650,6 +4675,14 @@ void __netdev_adjacent_dev_remove(struct net_device *dev,
         if (adj->master)
                 sysfs_remove_link(&(dev->dev.kobj), "master");
 
+        if (dev_list == &dev->adj_list.lower) {
+                sprintf(linkname, "lower_%s", adj_dev->name);
+                sysfs_remove_link(&(dev->dev.kobj), linkname);
+        } else if (dev_list == &dev->adj_list.upper) {
+                sprintf(linkname, "upper_%s", adj_dev->name);
+                sysfs_remove_link(&(dev->dev.kobj), linkname);
+        }
+
         list_del_rcu(&adj->list);
         pr_debug("dev_put for %s, because link removed from %s to %s\n",
                  adj_dev->name, dev->name, adj_dev->name);