[NET]: dev_mcast: add multicast list synchronization helpers

The method drivers currently use to synchronize multicast lists is not
very pretty:

- walk the multicast list
- search each entry on a copy of the previous list
- if new add to lower device
- walk the copy of the previous list
- search each entry on the current list
- if removed delete from lower device
- copy entire list

This patch adds a new field to struct dev_addr_list to store the
synchronization state and adds two helper functions for synchronization
and cleanup.

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

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index f193aba30384..e5af458ab04b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -190,6 +190,7 @@ struct dev_addr_list
         struct dev_addr_list    *next;
         u8                      da_addr[MAX_ADDR_LEN];
         u8                      da_addrlen;
+        u8                      da_synced;
         int                     da_users;
         int                     da_gusers;
 };
@@ -1103,6 +1104,8 @@ extern int		dev_unicast_delete(struct net_device *dev, void *addr, int alen);
 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 int              dev_mc_sync(struct net_device *to, struct net_device *from);
+extern void             dev_mc_unsync(struct net_device *to, struct net_device *from);
 extern void             dev_mc_discard(struct net_device *dev);
 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);