Re: [RFC] net: refactor multicast/unicast address list

On Wed, 2009-06-17 at 01:10 +0200, Johannes Berg wrote:

I'd like to get this patch into the .32 tree once it opens
http://johannes.sipsolutions.net/patches/kernel/all/LATEST/NNN-net-core-mc-sync-list.patch

+/**
+ * 	mc_unsync_from_dev - Remove synchronized addresses from the destination list
+ *	@to: destination list
+ *	@to_count: destination list count
+ *	@from: source device
+ *
+ * 	Remove all addresses that were added to the destination list by
+ * 	mc_sync_from_dev(). This function is intended to be called from
+ *	the * 	dev->stop function of layered software devices. The
+ *	destination list must be locked in whatever way the caller
+ *	manages it.
+ */
+void mc_unsync_from_dev(struct dev_addr_list **to, int *to_count,
+			struct net_device *from)
+{
+	netif_addr_lock_bh(from);
+	__dev_addr_unsync(to, to_count,
+			  &from->mc_list, &from->mc_count);
+	netif_addr_unlock_bh(from);
+}
+EXPORT_SYMBOL(mc_unsync_from_dev);

That can't work, of course, because the "to" list needs to be locked
_after_ "from" is locked, due mc_sync_from_dev() begin used in
ndo_set_multicast_list(). I guess I have to push out all the locking, by
just exporting __dev_addr_sync/__dev_addr_unsync.

Objections? Better ideas?

johannes