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>

9 files changed, 27 insertions, 22 deletions

diff --git a/drivers/net/plip.c b/drivers/net/plip.c
index 7e82a82422cf..ca4df7f4cf21 100644
--- a/drivers/net/plip.c
+++ b/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(). */
diff --git a/drivers/net/via-velocity.h b/drivers/net/via-velocity.h
index f7b33ae7a703..b5e120b0074b 100644
--- a/drivers/net/via-velocity.h
+++ b/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;
 }
 
 /**
diff --git a/drivers/net/wan/hdlc_cisco.c b/drivers/net/wan/hdlc_cisco.c
index b38ffa149aba..b1e5e5b69c2a 100644
--- a/drivers/net/wan/hdlc_cisco.c
+++ b/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;
 
diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index 2be1a1a2beb9..1ec09bb4a3ab 100644
--- a/include/linux/inetdevice.h
+++ b/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);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index af05186d5b36..8992fffb8104 100644
--- a/include/linux/netdevice.h
+++ b/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 */
diff --git a/net/core/dev.c b/net/core/dev.c
index fc2dc933bee5..5bdce97b8175 100644
--- a/net/core/dev.c
+++ b/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);
 
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index da14c49284f4..c2ff48fa18c7 100644
--- a/net/ipv4/devinet.c
+++ b/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))
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 179fcab866fc..10b24c02deb0 100644
--- a/net/ipv4/ipmr.c
+++ b/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;
                         }
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 4935b843bcca..b8cf2821f00d 100644
--- a/net/mac80211/main.c
+++ b/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;