net/core: Add event for a change in slave state

Add event which provides an indication on a change in the state
of a bonding slave. The event handler should cast the pointer to the
appropriate type (struct netdev_bonding_info) in order to get the
full info about the slave.
Signed-off-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -51,6 +51,7 @@
 #include <linux/netdev_features.h>
 #include <linux/neighbour.h>
 #include <uapi/linux/netdevice.h>
+#include <uapi/linux/if_bonding.h>
 
 struct netpoll_info;
 struct device;
@@ -2056,6 +2057,7 @@ struct pcpu_sw_netstats {
 #define NETDEV_RESEND_IGMP	0x0016
 #define NETDEV_PRECHANGEMTU	0x0017 /* notify before mtu change happened */
 #define NETDEV_CHANGEINFODATA	0x0018
+#define NETDEV_BONDING_INFO	0x0019
 
 int register_netdevice_notifier(struct notifier_block *nb);
 int unregister_netdevice_notifier(struct notifier_block *nb);
@@ -3494,6 +3496,19 @@ struct sk_buff *__skb_gso_segment(struct sk_buff *skb,
 struct sk_buff *skb_mac_gso_segment(struct sk_buff *skb,
 				    netdev_features_t features);
 
+struct netdev_bonding_info {
+	ifslave	slave;
+	ifbond	master;
+};
+
+struct netdev_notifier_bonding_info {
+	struct netdev_notifier_info info; /* must be first */
+	struct netdev_bonding_info  bonding_info;
+};
+
+void netdev_bonding_info_change(struct net_device *dev,
+				struct netdev_bonding_info *bonding_info);
+
 static inline
 struct sk_buff *skb_gso_segment(struct sk_buff *skb, netdev_features_t features)
 {

net/core/dev.c

@@ -5355,6 +5355,26 @@ void netdev_upper_dev_unlink(struct net_device *dev,
 }
 EXPORT_SYMBOL(netdev_upper_dev_unlink);
 
+/**
+ * netdev_bonding_info_change - Dispatch event about slave change
+ * @dev: device
+ * @netdev_bonding_info: info to dispatch
+ *
+ * Send NETDEV_BONDING_INFO to netdev notifiers with info.
+ * The caller must hold the RTNL lock.
+ */
+void netdev_bonding_info_change(struct net_device *dev,
+				struct netdev_bonding_info *bonding_info)
+{
+	struct netdev_notifier_bonding_info	info;
+
+	memcpy(&info.bonding_info, bonding_info,
+	       sizeof(struct netdev_bonding_info));
+	call_netdevice_notifiers_info(NETDEV_BONDING_INFO, dev,
+				      &info.info);
+}
+EXPORT_SYMBOL(netdev_bonding_info_change);
+
 void netdev_adjacent_add_links(struct net_device *dev)
 {
 	struct netdev_adjacent *iter;

net/core/rtnetlink.c

@@ -3180,6 +3180,7 @@ static int rtnetlink_event(struct notifier_block *this, unsigned long event, voi
 	case NETDEV_UNREGISTER_FINAL:
 	case NETDEV_RELEASE:
 	case NETDEV_JOIN:
+	case NETDEV_BONDING_INFO:
 		break;
 	default:
 		rtmsg_ifinfo(RTM_NEWLINK, dev, 0, GFP_KERNEL);