Merge branch 'bridge-fdbs-bitops'

Nikolay Aleksandrov says:

====================
net: bridge: convert fdbs to use bitops

We'd like to have a well-defined behaviour when changing fdb flags. The
problem is that we've added new fields which are changed from all
contexts without any locking. We are aware of the bit test/change races
and these are fine (we can remove them later), but it is considered
undefined behaviour to change bitfields from multiple threads and also
on some architectures that can result in unexpected results,
specifically when all fields between the changed ones are also
bitfields. The conversion to bitops shows the intent clearly and
makes them use functions with well-defined behaviour in such cases.
There is no overhead for the fast-path, the bit changing functions are
used only in special cases when learning and in the slow path.
In addition this conversion allows us to simplify fdb flag handling and
avoid bugs for future bits (e.g. a forgetting to clear the new bit when
allocating a new fdb). All bridge selftests passed, also tried all of the
converted bits manually in a VM.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_input.c

@@ -151,7 +151,7 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
 	if (dst) {
 		unsigned long now = jiffies;
 
-		if (dst->is_local)
+		if (test_bit(BR_FDB_LOCAL, &dst->flags))
 			return br_pass_frame_up(skb);
 
 		if (now != dst->used)

net/bridge/br_private.h

@@ -172,6 +172,16 @@ struct net_bridge_vlan_group {
 	u16				pvid;
 };
 
+/* bridge fdb flags */
+enum {
+	BR_FDB_LOCAL,
+	BR_FDB_STATIC,
+	BR_FDB_STICKY,
+	BR_FDB_ADDED_BY_USER,
+	BR_FDB_ADDED_BY_EXT_LEARN,
+	BR_FDB_OFFLOADED,
+};
+
 struct net_bridge_fdb_key {
 	mac_addr addr;
 	u16 vlan_id;
@@ -183,12 +193,7 @@ struct net_bridge_fdb_entry {
 
 	struct net_bridge_fdb_key	key;
 	struct hlist_node		fdb_node;
-	unsigned char			is_local:1,
-					is_static:1,
-					is_sticky:1,
-					added_by_user:1,
-					added_by_external_learn:1,
-					offloaded:1;
+	unsigned long			flags;
 
 	/* write-heavy members should not affect lookups */
 	unsigned long			updated ____cacheline_aligned_in_smp;

net/bridge/br_switchdev.c

@@ -129,15 +129,19 @@ br_switchdev_fdb_notify(const struct net_bridge_fdb_entry *fdb, int type)
 		br_switchdev_fdb_call_notifiers(false, fdb->key.addr.addr,
 						fdb->key.vlan_id,
 						fdb->dst->dev,
-						fdb->added_by_user,
-						fdb->offloaded);
+						test_bit(BR_FDB_ADDED_BY_USER,
+							 &fdb->flags),
+						test_bit(BR_FDB_OFFLOADED,
+							 &fdb->flags));
 		break;
 	case RTM_NEWNEIGH:
 		br_switchdev_fdb_call_notifiers(true, fdb->key.addr.addr,
 						fdb->key.vlan_id,
 						fdb->dst->dev,
-						fdb->added_by_user,
-						fdb->offloaded);
+						test_bit(BR_FDB_ADDED_BY_USER,
+							 &fdb->flags),
+						test_bit(BR_FDB_OFFLOADED,
+							 &fdb->flags));
 		break;
 	}
 }