Subject: Re: [net-next,v2,2/3] net: convert resend IGMP to notifier event

From: Veaceslav Falico <[email-masked]>
Date: Mon, 22 Jul 2013 18:26:06 +0200

On Sat, Jul 20, 2013 at 12:13:53PM +0200, Jiri Pirko wrote:
>Until now, bond_resend_igmp_join_requests() looks for vlans attached to
>bonding device, bridge where bonding act as port manually. It does not
>care of other scenarios, like stacked bonds or team device above. Make
>this more generic and use netdev notifier to propagate the event to
>upper devices and to actually call ip_mc_rejoin_groups().
>
>Signed-off-by: Jiri Pirko <[email-masked]>
>
>---
>drivers/net/bonding/bond_main.c | 44 ++++++++-------------------------------
> drivers/net/team/team.c         |  4 ++++
> include/linux/igmp.h            |  1 -
> include/linux/netdevice.h       |  1 +
> net/8021q/vlan.c                |  1 +
> net/bridge/br_notify.c          |  5 +++++
> net/ipv4/igmp.c                 | 46 +++++++++++++++++++++++++++++++++++------
> 7 files changed, 60 insertions(+), 42 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index 07f257d4..ae9864c 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -715,15 +715,6 @@ static int bond_set_allmulti(struct bonding *bond, int inc)
> 	return err;
> }
>
>-static void __bond_resend_igmp_join_requests(struct net_device *dev)
>-{
>-	struct in_device *in_dev;
>-
>-	in_dev = __in_dev_get_rcu(dev);
>-	if (in_dev)
>-		ip_mc_rejoin_groups(in_dev);
>-}
>-
> /*
>  * Retrieve the list of registered multicast addresses for the bonding
>  * device and retransmit an IGMP JOIN request to the current active
>@@ -731,33 +722,12 @@ static void __bond_resend_igmp_join_requests(struct net_device *dev)
>  */
> static void bond_resend_igmp_join_requests(struct bonding *bond)
> {
>-	struct net_device *bond_dev, *vlan_dev, *upper_dev;
>-	struct vlan_entry *vlan;
>-
>-	read_lock(&bond->lock);

I think you loose the bond->lock here, so that the igmp resend happens
without it, but under a rtnl_lock(), which is enough I bet. Win :), one
more bond->lock gone.

Acked-by: Veaceslav Falico <[email-masked]>

>-	rcu_read_lock();
>-
>-	bond_dev = bond->dev;
>-
>-	/* rejoin all groups on bond device */
>-	__bond_resend_igmp_join_requests(bond_dev);
>-
>-	/*
>-	 * if bond is enslaved to a bridge,
>-	 * then rejoin all groups on its master
>-	 */
>-	upper_dev = netdev_master_upper_dev_get_rcu(bond_dev);
>-	if (upper_dev && upper_dev->priv_flags & IFF_EBRIDGE)
>-		__bond_resend_igmp_join_requests(upper_dev);
>-
>-	/* rejoin all groups on vlan devices */
>-	list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
>-		vlan_dev = __vlan_find_dev_deep(bond_dev, htons(ETH_P_8021Q),
>-						vlan->vlan_id);
>-		if (vlan_dev)
>-			__bond_resend_igmp_join_requests(vlan_dev);
>+	if (!rtnl_trylock()) {
>+		queue_delayed_work(bond->wq, &bond->mcast_work, 0);
>+		return;
> 	}
>-	rcu_read_unlock();
>+	call_netdevice_notifiers(NETDEV_RESEND_IGMP, bond->dev);
>+	rtnl_unlock();
>
> 	/* We use curr_slave_lock to protect against concurrent access to
> 	 * igmp_retrans from multiple running instances of this function and
>@@ -3234,6 +3204,10 @@ static int bond_slave_netdev_event(unsigned long event,
> 	case NETDEV_FEAT_CHANGE:
> 		bond_compute_features(bond);
> 		break;
>+	case NETDEV_RESEND_IGMP:
>+		/* Propagate to master device */
>+		call_netdevice_notifiers(event, slave->bond->dev);
>+		break;
> 	default:
> 		break;
> 	}
>diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c
>index 0433ee9..2587dc8 100644
>--- a/drivers/net/team/team.c
>+++ b/drivers/net/team/team.c
>@@ -2785,6 +2785,10 @@ static int team_device_event(struct notifier_block *unused,
> 	case NETDEV_PRE_TYPE_CHANGE:
> 		/* Forbid to change type of underlaying device */
> 		return NOTIFY_BAD;
>+	case NETDEV_RESEND_IGMP:
>+		/* Propagate to master device */
>+		call_netdevice_notifiers(event, port->team->dev);
>+		break;
> 	}
> 	return NOTIFY_DONE;
> }
>diff --git a/include/linux/igmp.h b/include/linux/igmp.h
>index e3362b5..f47550d 100644
>--- a/include/linux/igmp.h
>+++ b/include/linux/igmp.h
>@@ -129,6 +129,5 @@ extern void ip_mc_unmap(struct in_device *);
> extern void ip_mc_remap(struct in_device *);
> extern void ip_mc_dec_group(struct in_device *in_dev, __be32 addr);
> extern void ip_mc_inc_group(struct in_device *in_dev, __be32 addr);
>-extern void ip_mc_rejoin_groups(struct in_device *in_dev);
>
> #endif
>diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>index 0741a1e..2bb2357 100644
>--- a/include/linux/netdevice.h
>+++ b/include/linux/netdevice.h
>@@ -1633,6 +1633,7 @@ struct packet_offload {
> #define NETDEV_NOTIFY_PEERS	0x0013
> #define NETDEV_JOIN		0x0014
> #define NETDEV_CHANGEUPPER	0x0015
>+#define NETDEV_RESEND_IGMP	0x0016
>
> extern int register_netdevice_notifier(struct notifier_block *nb);
> extern int unregister_netdevice_notifier(struct notifier_block *nb);
>diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
>index 2fb2d88..03a92e1 100644
>--- a/net/8021q/vlan.c
>+++ b/net/8021q/vlan.c
>@@ -459,6 +459,7 @@ static int vlan_device_event(struct notifier_block *unused, unsigned long event,
>
> 	case NETDEV_NOTIFY_PEERS:
> 	case NETDEV_BONDING_FAILOVER:
>+	case NETDEV_RESEND_IGMP:
> 		/* Propagate to vlan devices */
> 		vlan_group_for_each_dev(grp, i, vlandev)
> 			call_netdevice_notifiers(event, vlandev);
>diff --git a/net/bridge/br_notify.c b/net/bridge/br_notify.c
>index 3a3f371..2998dd1 100644
>--- a/net/bridge/br_notify.c
>+++ b/net/bridge/br_notify.c
>@@ -102,6 +102,11 @@ static int br_device_event(struct notifier_block *unused, unsigned long event, v
> 	case NETDEV_PRE_TYPE_CHANGE:
> 		/* Forbid underlaying device to change its type. */
> 		return NOTIFY_BAD;
>+
>+	case NETDEV_RESEND_IGMP:
>+		/* Propagate to master device */
>+		call_netdevice_notifiers(event, br->dev);
>+		break;
> 	}
>
> 	/* Events that may cause spanning tree to refresh */
>diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
>index cd71190..375aca3 100644
>--- a/net/ipv4/igmp.c
>+++ b/net/ipv4/igmp.c
>@@ -1323,16 +1323,17 @@ out:
> EXPORT_SYMBOL(ip_mc_inc_group);
>
> /*
>- *	Resend IGMP JOIN report; used for bonding.
>- *	Called with rcu_read_lock()
>+ *	Resend IGMP JOIN report; used by netdev notifier.
>  */
>-void ip_mc_rejoin_groups(struct in_device *in_dev)
>+static void ip_mc_rejoin_groups(struct in_device *in_dev)
> {
> #ifdef CONFIG_IP_MULTICAST
> 	struct ip_mc_list *im;
> 	int type;
>
>-	for_each_pmc_rcu(in_dev, im) {
>+	ASSERT_RTNL();
>+
>+	for_each_pmc_rtnl(in_dev, im) {
> 		if (im->multiaddr == IGMP_ALL_HOSTS)
> 			continue;
>
>@@ -1349,7 +1350,6 @@ void ip_mc_rejoin_groups(struct in_device *in_dev)
> 	}
> #endif
> }
>-EXPORT_SYMBOL(ip_mc_rejoin_groups);
>
> /*
>  *	A socket has left a multicast group on device dev
>@@ -2735,8 +2735,42 @@ static struct pernet_operations igmp_net_ops = {
> 	.exit = igmp_net_exit,
> };
>
>+static int igmp_netdev_event(struct notifier_block *this,
>+			     unsigned long event, void *ptr)
>+{
>+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
>+	struct in_device *in_dev;
>+
>+	switch (event) {
>+	case NETDEV_RESEND_IGMP:
>+		in_dev = __in_dev_get_rtnl(dev);
>+		if (in_dev)
>+			ip_mc_rejoin_groups(in_dev);
>+		break;
>+	default:
>+		break;
>+	}
>+	return NOTIFY_DONE;
>+}
>+
>+static struct notifier_block igmp_notifier = {
>+	.notifier_call = igmp_netdev_event,
>+};
>+
> int __init igmp_mc_proc_init(void)
> {
>-	return register_pernet_subsys(&igmp_net_ops);
>+	int err;
>+
>+	err = register_pernet_subsys(&igmp_net_ops);
>+	if (err)
>+		return err;
>+	err = register_netdevice_notifier(&igmp_notifier);
>+	if (err)
>+		goto reg_notif_fail;
>+	return 0;
>+
>+reg_notif_fail:
>+	unregister_pernet_subsys(&igmp_net_ops);
>+	return err;
> }
> #endif