[PATCH v2 net-next 3/5] net: bridge: use atomic ops to read/change p->flags (I)

[Eric Dumazet <edumazet@google.com>]

Use test_bit() in net/bridge/br_arp_nd_proxy.c,
net/bridge/br_fdb.c and net/bridge/br_forward.c.

Use READ_ONCE(p->flags) in br_recalculate_neigh_suppress_enabled()
as we test two bits at once.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/bridge/br_arp_nd_proxy.c | 22 +++++++---------------
 net/bridge/br_fdb.c          |  2 +-
 net/bridge/br_forward.c      | 15 ++++++++-------
 3 files changed, 16 insertions(+), 23 deletions(-)

diff --git a/net/bridge/br_arp_nd_proxy.c b/net/bridge/br_arp_nd_proxy.c
index 5263232278b4fe95775cfcbba71615197e2f5311..23eb6931a2b4ad9137ef20735d8333f376fd49f2 100644
--- a/net/bridge/br_arp_nd_proxy.c
+++ b/net/bridge/br_arp_nd_proxy.c
@@ -29,7 +29,7 @@ void br_recalculate_neigh_suppress_enabled(struct net_bridge *br)
 	bool neigh_suppress = false;
 
 	list_for_each_entry(p, &br->port_list, list) {
-		if (p->flags & (BR_NEIGH_SUPPRESS | BR_NEIGH_VLAN_SUPPRESS)) {
+		if (READ_ONCE(p->flags) & (BR_NEIGH_SUPPRESS | BR_NEIGH_VLAN_SUPPRESS)) {
 			neigh_suppress = true;
 			break;
 		}
@@ -206,8 +206,8 @@ void br_do_proxy_suppress_arp(struct sk_buff *skb, struct net_bridge *br,
 			const struct net_bridge_port *dst = READ_ONCE(f->dst);
 			bool replied = false;
 
-			if ((p && (p->flags & BR_PROXYARP)) ||
-			    (dst && (dst->flags & BR_PROXYARP_WIFI)) ||
+			if ((p && test_bit(BR_PROXYARP_BIT, &p->flags)) ||
+			    (dst && test_bit(BR_PROXYARP_WIFI_BIT, &dst->flags)) ||
 			    br_is_neigh_suppress_enabled(dst, vid)) {
 				if (!vid)
 					br_arp_send(br, p, skb->dev, sip, tip,
@@ -511,10 +511,7 @@ bool br_is_neigh_suppress_enabled(const struct net_bridge_port *p, u16 vid)
 	if (!p)
 		return false;
 
-	if (!vid)
-		return !!(p->flags & BR_NEIGH_SUPPRESS);
-
-	if (p->flags & BR_NEIGH_VLAN_SUPPRESS) {
+	if (vid && test_bit(BR_NEIGH_VLAN_SUPPRESS_BIT, &p->flags)) {
 		struct net_bridge_vlan_group *vg = nbp_vlan_group_rcu(p);
 		struct net_bridge_vlan *v;
 
@@ -522,17 +519,13 @@ bool br_is_neigh_suppress_enabled(const struct net_bridge_port *p, u16 vid)
 		if (!v)
 			return false;
 		return !!(v->priv_flags & BR_VLFLAG_NEIGH_SUPPRESS_ENABLED);
-	} else {
-		return !!(p->flags & BR_NEIGH_SUPPRESS);
 	}
+	return test_bit(BR_NEIGH_SUPPRESS_BIT, &p->flags);
 }
 
 bool br_is_neigh_forward_grat_enabled(const struct net_bridge_port *p, u16 vid)
 {
-	if (!vid)
-		return !!(p->flags & BR_NEIGH_FORWARD_GRAT);
-
-	if (p->flags & BR_NEIGH_VLAN_SUPPRESS) {
+	if (vid && test_bit(BR_NEIGH_VLAN_SUPPRESS_BIT, &p->flags)) {
 		struct net_bridge_vlan_group *vg = nbp_vlan_group_rcu(p);
 		struct net_bridge_vlan *v;
 
@@ -540,7 +533,6 @@ bool br_is_neigh_forward_grat_enabled(const struct net_bridge_port *p, u16 vid)
 		if (!v)
 			return false;
 		return !!(v->priv_flags & BR_VLFLAG_NEIGH_FORWARD_GRAT_ENABLED);
-	} else {
-		return !!(p->flags & BR_NEIGH_FORWARD_GRAT);
 	}
+	return test_bit(BR_NEIGH_FORWARD_GRAT_BIT, &p->flags);
 }
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index a114373c98163d1e81b090b9c799adcb1bfeed77..e4570bbed85445bcda08537b81c78bacd163f28d 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -1514,7 +1514,7 @@ int br_fdb_external_learn_add(struct net_bridge *br, struct net_bridge_port *p,
 
 	trace_br_fdb_external_learn_add(br, p, addr, vid);
 
-	if (locked && (!p || !(p->flags & BR_PORT_MAB)))
+	if (locked && (!p || !test_bit(BR_PORT_MAB_BIT, &p->flags)))
 		return -EINVAL;
 
 	spin_lock_bh(&br->hash_lock);
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 4a77d07433745152241789818949bd228aa95be0..46c762ca5177e5ffb8bc21077cdb14ca25a4a453 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -24,7 +24,7 @@ static inline int should_deliver(const struct net_bridge_port *p,
 	struct net_bridge_vlan_group *vg;
 
 	vg = nbp_vlan_group_rcu(p);
-	return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
+	return (test_bit(BR_HAIRPIN_MODE_BIT, &p->flags) || skb->dev != p->dev) &&
 		(br_mst_is_enabled(p) || p->state == BR_STATE_FORWARDING) &&
 		br_allowed_egress(vg, skb) && nbp_switchdev_allowed_egress(p, skb) &&
 		!br_skb_isolated(p, skb);
@@ -214,24 +214,24 @@ void br_flood(struct net_bridge *br, struct sk_buff *skb,
 		 */
 		switch (pkt_type) {
 		case BR_PKT_UNICAST:
-			if (!(p->flags & BR_FLOOD))
+			if (!test_bit(BR_FLOOD_BIT, &p->flags))
 				continue;
 			break;
 		case BR_PKT_MULTICAST:
-			if (!(p->flags & BR_MCAST_FLOOD) && skb->dev != br->dev)
+			if (!test_bit(BR_MCAST_FLOOD_BIT, &p->flags) && skb->dev != br->dev)
 				continue;
 			break;
 		case BR_PKT_BROADCAST:
-			if (!(p->flags & BR_BCAST_FLOOD) && skb->dev != br->dev)
+			if (!test_bit(BR_BCAST_FLOOD_BIT, &p->flags) && skb->dev != br->dev)
 				continue;
 			break;
 		}
 
 		/* Do not flood to ports that enable proxy ARP */
-		if (p->flags & BR_PROXYARP)
+		if (test_bit(BR_PROXYARP_BIT, &p->flags))
 			continue;
 		if (BR_INPUT_SKB_CB(skb)->proxyarp_replied) {
-			if (p->flags & BR_PROXYARP_WIFI)
+			if (test_bit(BR_PROXYARP_WIFI_BIT, &p->flags))
 				continue;
 			/* For gratuitous ARPs/NAs, check neigh_forward_grat.
 			 * For regular ARPs/NDs, check only neigh_suppress.
@@ -328,7 +328,8 @@ void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
 		if ((unsigned long)lport > (unsigned long)rport) {
 			port = lport;
 
-			if (port->flags & BR_MULTICAST_TO_UNICAST) {
+			if (test_bit(BR_MULTICAST_TO_UNICAST_BIT,
+				     &port->flags)) {
 				maybe_deliver_addr(lport, skb, p->eth_addr,
 						   local_orig);
 				goto delivered;
-- 
2.54.0.1099.g489fc7bff1-goog