[NET]: Fix secondary unicast/multicast address count maintenance

When a reference to an existing address is increased or decreased without
hitting zero, the address count is incorrectly adjusted.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -1091,8 +1091,8 @@ extern int		dev_unicast_add(struct net_device *dev, void *addr, int alen);
 extern int 		dev_mc_delete(struct net_device *dev, void *addr, int alen, int all);
 extern int		dev_mc_add(struct net_device *dev, void *addr, int alen, int newonly);
 extern void		dev_mc_discard(struct net_device *dev);
-extern int 		__dev_addr_delete(struct dev_addr_list **list, void *addr, int alen, int all);
-extern int		__dev_addr_add(struct dev_addr_list **list, void *addr, int alen, int newonly);
+extern int 		__dev_addr_delete(struct dev_addr_list **list, int *count, void *addr, int alen, int all);
+extern int		__dev_addr_add(struct dev_addr_list **list, int *count, void *addr, int alen, int newonly);
 extern void		__dev_addr_discard(struct dev_addr_list **list);
 extern void		dev_set_promiscuity(struct net_device *dev, int inc);
 extern void		dev_set_allmulti(struct net_device *dev, int inc);

net/core/dev.c

@@ -2607,8 +2607,8 @@ void dev_set_rx_mode(struct net_device *dev)
 	netif_tx_unlock_bh(dev);
 }
 
-int __dev_addr_delete(struct dev_addr_list **list, void *addr, int alen,
-		      int glbl)
+int __dev_addr_delete(struct dev_addr_list **list, int *count,
+		      void *addr, int alen, int glbl)
 {
 	struct dev_addr_list *da;
 
@@ -2626,13 +2626,15 @@ int __dev_addr_delete(struct dev_addr_list **list, void *addr, int alen,
 
 			*list = da->next;
 			kfree(da);
+			(*count)--;
 			return 0;
 		}
 	}
 	return -ENOENT;
 }
 
-int __dev_addr_add(struct dev_addr_list **list, void *addr, int alen, int glbl)
+int __dev_addr_add(struct dev_addr_list **list, int *count,
+		   void *addr, int alen, int glbl)
 {
 	struct dev_addr_list *da;
 
@@ -2659,6 +2661,7 @@ int __dev_addr_add(struct dev_addr_list **list, void *addr, int alen, int glbl)
 	da->da_gusers = glbl ? 1 : 0;
 	da->next = *list;
 	*list = da;
+	(*count)++;
 	return 0;
 }
 
@@ -2692,11 +2695,9 @@ int dev_unicast_delete(struct net_device *dev, void *addr, int alen)
 	ASSERT_RTNL();
 
 	netif_tx_lock_bh(dev);
-	err = __dev_addr_delete(&dev->uc_list, addr, alen, 0);
-	if (!err) {
-		dev->uc_count--;
+	err = __dev_addr_delete(&dev->uc_list, &dev->uc_count, addr, alen, 0);
+	if (!err)
 		__dev_set_rx_mode(dev);
-	}
 	netif_tx_unlock_bh(dev);
 	return err;
 }
@@ -2718,11 +2719,9 @@ int dev_unicast_add(struct net_device *dev, void *addr, int alen)
 	ASSERT_RTNL();
 
 	netif_tx_lock_bh(dev);
-	err = __dev_addr_add(&dev->uc_list, addr, alen, 0);
-	if (!err) {
-		dev->uc_count++;
+	err = __dev_addr_add(&dev->uc_list, &dev->uc_count, addr, alen, 0);
+	if (!err)
 		__dev_set_rx_mode(dev);
-	}
 	netif_tx_unlock_bh(dev);
 	return err;
 }

net/core/dev_mcast.c

@@ -72,10 +72,9 @@ int dev_mc_delete(struct net_device *dev, void *addr, int alen, int glbl)
 	int err;
 
 	netif_tx_lock_bh(dev);
-	err = __dev_addr_delete(&dev->mc_list, addr, alen, glbl);
+	err = __dev_addr_delete(&dev->mc_list, &dev->mc_count,
+				addr, alen, glbl);
 	if (!err) {
-		dev->mc_count--;
-
 		/*
 		 *	We have altered the list, so the card
 		 *	loaded filter is now wrong. Fix it
@@ -96,11 +95,9 @@ int dev_mc_add(struct net_device *dev, void *addr, int alen, int glbl)
 	int err;
 
 	netif_tx_lock_bh(dev);
-	err = __dev_addr_add(&dev->mc_list, addr, alen, glbl);
-	if (!err) {
-		dev->mc_count++;
+	err = __dev_addr_add(&dev->mc_list, &dev->mc_count, addr, alen, glbl);
+	if (!err)
 		__dev_set_rx_mode(dev);
-	}
 	netif_tx_unlock_bh(dev);
 	return err;
 }