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);