bonding: rejoin multicast groups on VLANs

During a failover, the IGMP membership is sent to update
the switch restoring the traffic, but it misses groups added
to VLAN devices running on top of bonding devices.

This patch changes it to iterate over all VLAN devices
on top of it sending IGMP memberships too.

Signed-off-by: Flavio Leitner <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/bonding/bond_main.c

···
 }
 
 
+static void __bond_resend_igmp_join_requests(struct net_device *dev)
+{
+	struct in_device *in_dev;
+	struct ip_mc_list *im;
+
+	rcu_read_lock();
+	in_dev = __in_dev_get_rcu(dev);
+	if (in_dev) {
+		for (im = in_dev->mc_list; im; im = im->next)
+			ip_mc_rejoin_group(im);
+	}
+
+	rcu_read_unlock();
+}
+
 /*
  * Retrieve the list of registered multicast addresses for the bonding
  * device and retransmit an IGMP JOIN request to the current active
···
  */
 static void bond_resend_igmp_join_requests(struct bonding *bond)
 {
-	struct in_device *in_dev;
-	struct ip_mc_list *im;
+	struct net_device *vlan_dev;
+	struct vlan_entry *vlan;
 
-	rcu_read_lock();
-	in_dev = __in_dev_get_rcu(bond->dev);
-	if (in_dev) {
-		for (im = in_dev->mc_list; im; im = im->next)
-			ip_mc_rejoin_group(im);
+	read_lock(&bond->lock);
+
+	/* rejoin all groups on bond device */
+	__bond_resend_igmp_join_requests(bond->dev);
+
+	/* rejoin all groups on vlan devices */
+	if (bond->vlgrp) {
+		list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
+			vlan_dev = vlan_group_get_device(bond->vlgrp,
+							 vlan->vlan_id);
+			if (vlan_dev)
+				__bond_resend_igmp_join_requests(vlan_dev);
+		}
 	}
 
-	rcu_read_unlock();
+	read_unlock(&bond->lock);
+}
+
+void bond_resend_igmp_join_requests_delayed(struct work_struct *work)
+{
+	struct bonding *bond = container_of(work, struct bonding,
+							mcast_work.work);
+	bond_resend_igmp_join_requests(bond);
 }
 
 /*
···
 
 		netdev_for_each_mc_addr(ha, bond->dev)
 			dev_mc_add(new_active->dev, ha->addr);
-		bond_resend_igmp_join_requests(bond);
 	}
 }
 
···
 		}
 	}
 
-	/* resend IGMP joins since all were sent on curr_active_slave */
-	if (bond->params.mode == BOND_MODE_ROUNDROBIN) {
-		bond_resend_igmp_join_requests(bond);
+	/* resend IGMP joins since active slave has changed or
+	 * all were sent on curr_active_slave */
+	if ((USES_PRIMARY(bond->params.mode) && new_active) ||
+	    bond->params.mode == BOND_MODE_ROUNDROBIN) {
+		queue_delayed_work(bond->wq, &bond->mcast_work, 0);
 	}
 }
 
···
 
 	bond->kill_timers = 0;
 
+	INIT_DELAYED_WORK(&bond->mcast_work, bond_resend_igmp_join_requests_delayed);
+
 	if (bond_is_lb(bond)) {
 		/* bond_alb_initialize must be called before the timer
 		 * is started.
···
 		break;
 	}
 
+	if (delayed_work_pending(&bond->mcast_work))
+		cancel_delayed_work(&bond->mcast_work);
 
 	if (bond_is_lb(bond)) {
 		/* Must be called only after all
···
 	if (bond->params.mode == BOND_MODE_8023AD &&
 	    delayed_work_pending(&bond->ad_work))
 		cancel_delayed_work(&bond->ad_work);
+
+	if (delayed_work_pending(&bond->mcast_work))
+		cancel_delayed_work(&bond->mcast_work);
 }
 
 /*

drivers/net/bonding/bonding.h

···
 	struct   delayed_work arp_work;
 	struct   delayed_work alb_work;
 	struct   delayed_work ad_work;
+	struct   delayed_work mcast_work;
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 	struct   in6_addr master_ipv6;
 #endif