netdev - [net-next v2 07/11] net: bridge: mcast: prepare add-router function for mcast router split

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Date:   Sun,  9 May 2021 21:45:05 +0200
From:   Linus Lüssing <linus.luessing@...3.blue>
To:     netdev@...r.kernel.org
Cc:     Roopa Prabhu <roopa@...dia.com>,
        Nikolay Aleksandrov <nikolay@...dia.com>,
        Jakub Kicinski <kuba@...nel.org>,
        "David S . Miller" <davem@...emloft.net>,
        bridge@...ts.linux-foundation.org, b.a.t.m.a.n@...ts.open-mesh.org,
        linux-kernel@...r.kernel.org,
        Linus Lüssing <linus.luessing@...3.blue>
Subject: [net-next v2 07/11] net: bridge: mcast: prepare add-router function for mcast router split

In preparation for the upcoming split of multicast router state into
their IPv4 and IPv6 variants move the protocol specific router list
access to an ip4 wrapper function.

Signed-off-by: Linus Lüssing <linus.luessing@...3.blue>
---
 net/bridge/br_multicast.c | 59 +++++++++++++++++++++++++++------------
 1 file changed, 41 insertions(+), 18 deletions(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 6c844b2..839d21b 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -51,8 +51,8 @@ static const struct rhashtable_params br_sg_port_rht_params = {
 
 static void br_multicast_start_querier(struct net_bridge *br,
 				       struct bridge_mcast_own_query *query);
-static void br_multicast_add_router(struct net_bridge *br,
-				    struct net_bridge_port *port);
+static void br_ip4_multicast_add_router(struct net_bridge *br,
+					struct net_bridge_port *port);
 static void br_ip4_multicast_leave_group(struct net_bridge *br,
 					 struct net_bridge_port *port,
 					 __be32 group,
@@ -1689,7 +1689,7 @@ static void __br_multicast_enable_port(struct net_bridge_port *port)
 #endif
 	if (port->multicast_router == MDB_RTR_TYPE_PERM &&
 	    hlist_unhashed(&port->ip4_rlist))
-		br_multicast_add_router(br, port);
+		br_ip4_multicast_add_router(br, port);
 }
 
 void br_multicast_enable_port(struct net_bridge_port *port)
@@ -2659,28 +2659,51 @@ static void br_port_mc_router_state_change(struct net_bridge_port *p,
  *  and locked by br->multicast_lock and RCU
  */
 static void br_multicast_add_router(struct net_bridge *br,
-				    struct net_bridge_port *port)
+				    struct net_bridge_port *port,
+				    struct hlist_node *slot,
+				    struct hlist_node *rlist,
+				    struct hlist_head *mc_router_list)
 {
-	struct net_bridge_port *p;
-	struct hlist_node *slot = NULL;
-
-	if (!hlist_unhashed(&port->ip4_rlist))
+	if (!hlist_unhashed(rlist))
 		return;
 
-	hlist_for_each_entry(p, &br->ip4_mc_router_list, ip4_rlist) {
-		if ((unsigned long) port >= (unsigned long) p)
-			break;
-		slot = &p->ip4_rlist;
-	}
-
 	if (slot)
-		hlist_add_behind_rcu(&port->ip4_rlist, slot);
+		hlist_add_behind_rcu(rlist, slot);
 	else
-		hlist_add_head_rcu(&port->ip4_rlist, &br->ip4_mc_router_list);
+		hlist_add_head_rcu(rlist, mc_router_list);
+
 	br_rtr_notify(br->dev, port, RTM_NEWMDB);
 	br_port_mc_router_state_change(port, true);
 }
 
+struct hlist_node *
+br_ip4_multicast_get_rport_slot(struct net_bridge *br, struct net_bridge_port *port)
+{
+	struct hlist_node *slot = NULL;
+	struct net_bridge_port *p;
+
+	hlist_for_each_entry(p, &br->ip4_mc_router_list, ip4_rlist) {
+		if ((unsigned long)port >= (unsigned long)p)
+			break;
+		slot = &p->ip4_rlist;
+	}
+
+	return slot;
+}
+
+/* Add port to router_list
+ *  list is maintained ordered by pointer value
+ *  and locked by br->multicast_lock and RCU
+ */
+static void br_ip4_multicast_add_router(struct net_bridge *br,
+					struct net_bridge_port *port)
+{
+	struct hlist_node *slot = br_ip4_multicast_get_rport_slot(br, port);
+
+	br_multicast_add_router(br, port, slot, &port->ip4_rlist,
+				&br->ip4_mc_router_list);
+}
+
 static void br_multicast_mark_router(struct net_bridge *br,
 				     struct net_bridge_port *port)
 {
@@ -2700,7 +2723,7 @@ static void br_multicast_mark_router(struct net_bridge *br,
 	    port->multicast_router == MDB_RTR_TYPE_PERM)
 		return;
 
-	br_multicast_add_router(br, port);
+	br_ip4_multicast_add_router(br, port);
 
 	mod_timer(&port->ip4_mc_router_timer,
 		  now + br->multicast_querier_interval);
@@ -3526,7 +3549,7 @@ int br_multicast_set_port_router(struct net_bridge_port *p, unsigned long val)
 	case MDB_RTR_TYPE_PERM:
 		p->multicast_router = MDB_RTR_TYPE_PERM;
 		del_timer(&p->ip4_mc_router_timer);
-		br_multicast_add_router(br, p);
+		br_ip4_multicast_add_router(br, p);
 		break;
 	case MDB_RTR_TYPE_TEMP:
 		p->multicast_router = MDB_RTR_TYPE_TEMP;
-- 
2.31.0