ip: Router Alert RCU conversion

Straightforward conversion to RCU.

One rwlock becomes a spinlock, and is static.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 8 deletions

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index d52c9da644cf..d274078b1665 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -146,7 +146,7 @@
 #include <linux/netlink.h>
 
 /*
- *      Process Router Attention IP option
+ *      Process Router Attention IP option (RFC 2113)
  */
 int ip_call_ra_chain(struct sk_buff *skb)
 {
@@ -155,8 +155,7 @@ int ip_call_ra_chain(struct sk_buff *skb)
         struct sock *last = NULL;
         struct net_device *dev = skb->dev;
 
-        read_lock(&ip_ra_lock);
-        for (ra = ip_ra_chain; ra; ra = ra->next) {
+        for (ra = rcu_dereference(ip_ra_chain); ra; ra = rcu_dereference(ra->next)) {
                 struct sock *sk = ra->sk;
 
                 /* If socket is bound to an interface, only report
@@ -167,10 +166,8 @@ int ip_call_ra_chain(struct sk_buff *skb)
                      sk->sk_bound_dev_if == dev->ifindex) &&
                     net_eq(sock_net(sk), dev_net(dev))) {
                         if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) {
-                                if (ip_defrag(skb, IP_DEFRAG_CALL_RA_CHAIN)) {
-                                        read_unlock(&ip_ra_lock);
+                                if (ip_defrag(skb, IP_DEFRAG_CALL_RA_CHAIN))
                                         return 1;
-                                }
                         }
                         if (last) {
                                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
@@ -183,10 +180,8 @@ int ip_call_ra_chain(struct sk_buff *skb)
 
         if (last) {
                 raw_rcv(last, skb);
-                read_unlock(&ip_ra_lock);
                 return 1;
         }
-        read_unlock(&ip_ra_lock);
         return 0;
 }