ipv4: ip_ptr cleanups

dev->ip_ptr is protected by rtnl and rcu.

Yet some places dont use appropriate primitives and/or locking rules.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/plip.c

@@ -995,8 +995,10 @@ plip_tx_packet(struct sk_buff *skb, struct net_device *dev)
 static void
 plip_rewrite_address(const struct net_device *dev, struct ethhdr *eth)
 {
-	const struct in_device *in_dev = dev->ip_ptr;
+	const struct in_device *in_dev;
 
+	rcu_read_lock();
+	in_dev = __in_dev_get_rcu(dev);
 	if (in_dev) {
 		/* Any address will do - we take the first */
 		const struct in_ifaddr *ifa = in_dev->ifa_list;
@@ -1006,6 +1008,7 @@ plip_rewrite_address(const struct net_device *dev, struct ethhdr *eth)
 			memcpy(eth->h_dest+2, &ifa->ifa_address, 4);
 		}
 	}
+	rcu_read_unlock();
 }
 
 static int
@@ -1088,7 +1091,8 @@ plip_open(struct net_device *dev)
 	   when the device address isn't identical to the address of a
 	   received frame, the kernel incorrectly drops it).             */
 
-	if ((in_dev=dev->ip_ptr) != NULL) {
+	in_dev=__in_dev_get_rtnl(dev);
+	if (in_dev) {
 		/* Any address will do - we take the first. We already
 		   have the first two bytes filled with 0xfc, from
 		   plip_init_dev(). */

drivers/net/via-velocity.h

@@ -1504,22 +1504,25 @@ struct velocity_info {
  *	addresses on this chain then we use the first - multi-IP WOL is not
  *	supported.
  *
- *	CHECK ME: locking
  */
 
 static inline int velocity_get_ip(struct velocity_info *vptr)
 {
-	struct in_device *in_dev = (struct in_device *) vptr->dev->ip_ptr;
+	struct in_device *in_dev;
 	struct in_ifaddr *ifa;
+	int res = -ENOENT;
 
+	rcu_read_lock();
+	in_dev = __in_dev_get_rcu(vptr->dev);
 	if (in_dev != NULL) {
 		ifa = (struct in_ifaddr *) in_dev->ifa_list;
 		if (ifa != NULL) {
 			memcpy(vptr->ip_addr, &ifa->ifa_address, 4);
-			return 0;
+			res = 0;
 		}
 	}
-	return -ENOENT;
+	rcu_read_unlock();
+	return res;
 }
 
 /**

drivers/net/wan/hdlc_cisco.c

@@ -191,7 +191,8 @@ static int cisco_rx(struct sk_buff *skb)
 
 		switch (ntohl (cisco_data->type)) {
 		case CISCO_ADDR_REQ: /* Stolen from syncppp.c :-) */
-			in_dev = dev->ip_ptr;
+			rcu_read_lock();
+			in_dev = __in_dev_get_rcu(dev);
 			addr = 0;
 			mask = ~cpu_to_be32(0); /* is the mask correct? */
 
@@ -211,6 +212,7 @@ static int cisco_rx(struct sk_buff *skb)
 				cisco_keepalive_send(dev, CISCO_ADDR_REPLY,
 						     addr, mask);
 			}
+			rcu_read_unlock();
 			dev_kfree_skb_any(skb);
 			return NET_RX_SUCCESS;
 

include/linux/inetdevice.h

@@ -9,6 +9,7 @@
 #include <linux/rcupdate.h>
 #include <linux/timer.h>
 #include <linux/sysctl.h>
+#include <linux/rtnetlink.h>
 
 enum
 {
@@ -198,14 +199,10 @@ static __inline__ int bad_mask(__be32 mask, __be32 addr)
 
 static inline struct in_device *__in_dev_get_rcu(const struct net_device *dev)
 {
-	struct in_device *in_dev = dev->ip_ptr;
-	if (in_dev)
-		in_dev = rcu_dereference(in_dev);
-	return in_dev;
+	return rcu_dereference(dev->ip_ptr);
 }
 
-static __inline__ struct in_device *
-in_dev_get(const struct net_device *dev)
+static inline struct in_device *in_dev_get(const struct net_device *dev)
 {
 	struct in_device *in_dev;
 
@@ -217,10 +214,9 @@ in_dev_get(const struct net_device *dev)
 	return in_dev;
 }
 
-static __inline__ struct in_device *
-__in_dev_get_rtnl(const struct net_device *dev)
+static inline struct in_device *__in_dev_get_rtnl(const struct net_device *dev)
 {
-	return (struct in_device*)dev->ip_ptr;
+	return rcu_dereference_check(dev->ip_ptr, lockdep_rtnl_is_held());
 }
 
 extern void in_dev_finish_destroy(struct in_device *idev);

include/linux/netdevice.h

@@ -942,7 +942,7 @@ struct net_device {
 	void			*dsa_ptr;	/* dsa specific data */
 #endif
 	void 			*atalk_ptr;	/* AppleTalk link 	*/
-	void			*ip_ptr;	/* IPv4 specific data	*/
+	struct in_device __rcu	*ip_ptr;	/* IPv4 specific data	*/
 	void                    *dn_ptr;        /* DECnet specific data */
 	void                    *ip6_ptr;       /* IPv6 specific data */
 	void			*ec_ptr;	/* Econet specific data	*/

net/core/dev.c

@@ -5286,7 +5286,7 @@ void netdev_run_todo(void)
 
 		/* paranoia */
 		BUG_ON(atomic_read(&dev->refcnt));
-		WARN_ON(dev->ip_ptr);
+		WARN_ON(rcu_dereference_raw(dev->ip_ptr));
 		WARN_ON(dev->ip6_ptr);
 		WARN_ON(dev->dn_ptr);
 

net/ipv4/devinet.c

@@ -209,7 +209,7 @@ static void inetdev_destroy(struct in_device *in_dev)
 		inet_free_ifa(ifa);
 	}
 
-	dev->ip_ptr = NULL;
+	rcu_assign_pointer(dev->ip_ptr, NULL);
 
 	devinet_sysctl_unregister(in_dev);
 	neigh_parms_release(&arp_tbl, in_dev->arp_parms);
@@ -1059,7 +1059,7 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
 	switch (event) {
 	case NETDEV_REGISTER:
 		printk(KERN_DEBUG "inetdev_event: bug\n");
-		dev->ip_ptr = NULL;
+		rcu_assign_pointer(dev->ip_ptr, NULL);
 		break;
 	case NETDEV_UP:
 		if (!inetdev_valid_mtu(dev->mtu))

net/ipv4/ipmr.c

@@ -724,7 +724,7 @@ static int vif_add(struct net *net, struct mr_table *mrt,
 	case 0:
 		if (vifc->vifc_flags == VIFF_USE_IFINDEX) {
 			dev = dev_get_by_index(net, vifc->vifc_lcl_ifindex);
-			if (dev && dev->ip_ptr == NULL) {
+			if (dev && __in_dev_get_rtnl(dev) == NULL) {
 				dev_put(dev);
 				return -EADDRNOTAVAIL;
 			}

net/mac80211/main.c

@@ -362,7 +362,7 @@ static int ieee80211_ifa_changed(struct notifier_block *nb,
 	if (sdata->vif.type != NL80211_IFTYPE_STATION)
 		return NOTIFY_DONE;
 
-	idev = sdata->dev->ip_ptr;
+	idev = __in_dev_get_rtnl(sdata->dev);
 	if (!idev)
 		return NOTIFY_DONE;