[PATCH net-next v2 5/9] net: bridge: vlan: annotate lockless use of private flags

[Nikolay Aleksandrov <razor@blackwall.org>]

Annotate vlan private flags data races, they can be read lockless.

Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
---
 net/bridge/br_arp_nd_proxy.c |  6 ++++--
 net/bridge/br_multicast.c    | 16 ++++++++++------
 net/bridge/br_private.h      |  9 ++++++---
 net/bridge/br_vlan.c         |  2 +-
 net/bridge/br_vlan_options.c |  6 ++++--
 5 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/net/bridge/br_arp_nd_proxy.c b/net/bridge/br_arp_nd_proxy.c
index 87a40e2f1c50..b82fa6589ab9 100644
--- a/net/bridge/br_arp_nd_proxy.c
+++ b/net/bridge/br_arp_nd_proxy.c
@@ -521,7 +521,8 @@ bool br_is_neigh_suppress_enabled(const struct net_bridge_port *p, u16 vid)
 		v = br_vlan_find(vg, vid);
 		if (!v)
 			return false;
-		return !!(v->priv_flags & BR_VLFLAG_NEIGH_SUPPRESS_ENABLED);
+		return !!(READ_ONCE(v->priv_flags) &
+			  BR_VLFLAG_NEIGH_SUPPRESS_ENABLED);
 	}
 	return test_bit(BR_NEIGH_SUPPRESS_BIT, &p->flags);
 }
@@ -535,7 +536,8 @@ bool br_is_neigh_forward_grat_enabled(const struct net_bridge_port *p, u16 vid)
 		v = br_vlan_find(vg, vid);
 		if (!v)
 			return false;
-		return !!(v->priv_flags & BR_VLFLAG_NEIGH_FORWARD_GRAT_ENABLED);
+		return !!(READ_ONCE(v->priv_flags) &
+			  BR_VLFLAG_NEIGH_FORWARD_GRAT_ENABLED);
 	}
 	return test_bit(BR_NEIGH_FORWARD_GRAT_BIT, &p->flags);
 }
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index bbcaedf15ca1..cd984173320f 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -2172,7 +2172,7 @@ static void br_multicast_enable_port_ctx(struct net_bridge_mcast_port *pmctx)
 
 	spin_lock_bh(&br->multicast_lock);
 	if (br_multicast_port_ctx_is_vlan(pmctx) &&
-	    !(pmctx->vlan->priv_flags & BR_VLFLAG_MCAST_ENABLED)) {
+	    !(READ_ONCE(pmctx->vlan->priv_flags) & BR_VLFLAG_MCAST_ENABLED)) {
 		spin_unlock_bh(&br->multicast_lock);
 		return;
 	}
@@ -2209,7 +2209,7 @@ static void br_multicast_disable_port_ctx(struct net_bridge_mcast_port *pmctx)
 
 	spin_lock_bh(&br->multicast_lock);
 	if (br_multicast_port_ctx_is_vlan(pmctx) &&
-	    !(pmctx->vlan->priv_flags & BR_VLFLAG_MCAST_ENABLED)) {
+	    !(READ_ONCE(pmctx->vlan->priv_flags) & BR_VLFLAG_MCAST_ENABLED)) {
 		spin_unlock_bh(&br->multicast_lock);
 		return;
 	}
@@ -4083,7 +4083,8 @@ int br_multicast_rcv(struct net_bridge_mcast **brmctx,
 			*pmctx = &vlan->port_mcast_ctx;
 		}
 
-		if (!(masterv->priv_flags & BR_VLFLAG_GLOBAL_MCAST_ENABLED))
+		if (!(READ_ONCE(masterv->priv_flags) &
+		      BR_VLFLAG_GLOBAL_MCAST_ENABLED))
 			return 0;
 	}
 
@@ -4383,7 +4384,8 @@ void br_multicast_toggle_one_vlan(struct net_bridge_vlan *vlan, bool on)
 			return;
 
 		spin_lock_bh(&br->multicast_lock);
-		vlan->priv_flags ^= BR_VLFLAG_MCAST_ENABLED;
+		WRITE_ONCE(vlan->priv_flags, vlan->priv_flags ^
+					    BR_VLFLAG_MCAST_ENABLED);
 		spin_unlock_bh(&br->multicast_lock);
 
 		if (on)
@@ -4399,7 +4401,8 @@ void br_multicast_toggle_one_vlan(struct net_bridge_vlan *vlan, bool on)
 
 		br = vlan->port->br;
 		spin_lock_bh(&br->multicast_lock);
-		vlan->priv_flags ^= BR_VLFLAG_MCAST_ENABLED;
+		WRITE_ONCE(vlan->priv_flags, vlan->priv_flags ^
+					    BR_VLFLAG_MCAST_ENABLED);
 		if (on)
 			__br_multicast_enable_port_ctx(&vlan->port_mcast_ctx);
 		else
@@ -4477,7 +4480,8 @@ bool br_multicast_toggle_global_vlan(struct net_bridge_vlan *vlan, bool on)
 	if (on == !!(vlan->priv_flags & BR_VLFLAG_GLOBAL_MCAST_ENABLED))
 		return false;
 
-	vlan->priv_flags ^= BR_VLFLAG_GLOBAL_MCAST_ENABLED;
+	WRITE_ONCE(vlan->priv_flags, vlan->priv_flags ^
+				    BR_VLFLAG_GLOBAL_MCAST_ENABLED);
 	br_multicast_toggle_vlan(vlan, on);
 
 	return true;
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 96554d293d22..c7b64b5da012 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -1273,21 +1273,24 @@ br_multicast_ctx_vlan_global_disabled(const struct net_bridge_mcast *brmctx)
 {
 	return br_multicast_ctx_is_vlan(brmctx) &&
 	       (!br_opt_get(brmctx->br, BROPT_MCAST_VLAN_SNOOPING_ENABLED) ||
-		!(brmctx->vlan->priv_flags & BR_VLFLAG_GLOBAL_MCAST_ENABLED));
+		!(READ_ONCE(brmctx->vlan->priv_flags) &
+		  BR_VLFLAG_GLOBAL_MCAST_ENABLED));
 }
 
 static inline bool
 br_multicast_ctx_vlan_disabled(const struct net_bridge_mcast *brmctx)
 {
 	return br_multicast_ctx_is_vlan(brmctx) &&
-	       !(brmctx->vlan->priv_flags & BR_VLFLAG_MCAST_ENABLED);
+	       !(READ_ONCE(brmctx->vlan->priv_flags) &
+		 BR_VLFLAG_MCAST_ENABLED);
 }
 
 static inline bool
 br_multicast_port_ctx_vlan_disabled(const struct net_bridge_mcast_port *pmctx)
 {
 	return br_multicast_port_ctx_is_vlan(pmctx) &&
-	       !(pmctx->vlan->priv_flags & BR_VLFLAG_MCAST_ENABLED);
+	       !(READ_ONCE(pmctx->vlan->priv_flags) &
+		 BR_VLFLAG_MCAST_ENABLED);
 }
 
 static inline bool
diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index c8b2e3bfd42d..102792f20a5e 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -1497,7 +1497,7 @@ int br_vlan_fill_forward_path_mode(struct net_bridge *br,
 
 	if (path->bridge.vlan_mode == DEV_PATH_BR_VLAN_TAG)
 		path->bridge.vlan_mode = DEV_PATH_BR_VLAN_KEEP;
-	else if (v->priv_flags & BR_VLFLAG_TAGGING_BY_SWITCHDEV)
+	else if (READ_ONCE(v->priv_flags) & BR_VLFLAG_TAGGING_BY_SWITCHDEV)
 		path->bridge.vlan_mode = DEV_PATH_BR_VLAN_UNTAG_HW;
 	else
 		path->bridge.vlan_mode = DEV_PATH_BR_VLAN_UNTAG;
diff --git a/net/bridge/br_vlan_options.c b/net/bridge/br_vlan_options.c
index cb0f556ff40d..bd049d268fe7 100644
--- a/net/bridge/br_vlan_options.c
+++ b/net/bridge/br_vlan_options.c
@@ -276,7 +276,8 @@ static int br_vlan_process_one_opts(const struct net_bridge *br,
 		}
 
 		if (val != enabled) {
-			v->priv_flags ^= BR_VLFLAG_NEIGH_SUPPRESS_ENABLED;
+			WRITE_ONCE(v->priv_flags, v->priv_flags ^
+				   BR_VLFLAG_NEIGH_SUPPRESS_ENABLED);
 			*changed = true;
 		}
 	}
@@ -292,7 +293,8 @@ static int br_vlan_process_one_opts(const struct net_bridge *br,
 		}
 
 		if (val != enabled) {
-			v->priv_flags ^= BR_VLFLAG_NEIGH_FORWARD_GRAT_ENABLED;
+			WRITE_ONCE(v->priv_flags, v->priv_flags ^
+				   BR_VLFLAG_NEIGH_FORWARD_GRAT_ENABLED);
 			*changed = true;
 		}
 	}
-- 
2.47.3