[PATCH] convert icmpv6_socket to per-cpu data

[Christoph Hellwig <hch@xxxxxx>]

per-cpu data works in modules for a while now.  Also bring over a
comment from the IPv4 version and consolidate the error handling.


--- 1.40/net/ipv6/icmp.c        Mon Aug 18 12:38:34 2003
+++ edited/net/ipv6/icmp.c      Fri Aug 29 12:11:40 2003
@@ -70,12 +70,14 @@
 DEFINE_SNMP_STAT(struct icmpv6_mib, icmpv6_statistics);
 
 /*
- *     ICMP socket(s) for flow control.
+ *     The ICMP socket(s). This is the most convenient way to flow control
+ *     our ICMP output as well as maintain a clean interface throughout
+ *     all layers. All Socketless IP sends will soon be gone.
+ *
+ *     On SMP we have one ICMP socket per-cpu.
  */
-
-/* XXX We can't use per_cpu because this can be modular... */
-static struct socket *__icmpv6_socket[NR_CPUS];
-#define icmpv6_socket  __icmpv6_socket[smp_processor_id()]
+static DEFINE_PER_CPU(struct socket *, __icmpv6_socket) = NULL;
+#define icmpv6_socket  __get_cpu_var(__icmpv6_socket)
 
 static int icmpv6_rcv(struct sk_buff **pskb, unsigned int *nhoffp);
 
@@ -96,6 +98,7 @@
 static __inline__ void icmpv6_xmit_lock(void)
 {
        local_bh_disable();
+
        if (unlikely(!spin_trylock(&icmpv6_socket->sk->sk_lock.slock)))
                BUG();
 }
@@ -657,33 +660,23 @@
 int __init icmpv6_init(struct net_proto_family *ops)
 {
        struct sock *sk;
-       int i;
+       int err, i, j;
 
        for (i = 0; i < NR_CPUS; i++) {
-               int err;
-
                if (!cpu_possible(i))
                        continue;
 
                err = sock_create(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6,
-                                 &__icmpv6_socket[i]);
+                                 &per_cpu(__icmpv6_socket, i));
                if (err < 0) {
-                       int j;
-
                        printk(KERN_ERR
                               "Failed to initialize the ICMP6 control socket "
                               "(err %d).\n",
                               err);
-                       for (j = 0; j < i; j++) {
-                               if (!cpu_possible(j))
-                                       continue;
-                               sock_release(__icmpv6_socket[j]);
-                               __icmpv6_socket[j] = NULL; /* for safety */
-                       }
-                       return err;
+                       goto fail;
                }
 
-               sk = __icmpv6_socket[i]->sk;
+               sk = per_cpu(__icmpv6_socket, i)->sk;
                sk->sk_allocation = GFP_ATOMIC;
                sk->sk_sndbuf = SK_WMEM_MAX * 2;
                sk->sk_prot->unhash(sk);
@@ -692,16 +685,20 @@
 
        if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) {
                printk(KERN_ERR "Failed to register ICMP6 protocol\n");
-               for (i = 0; i < NR_CPUS; i++) {
-                       if (!cpu_possible(i))
-                               continue;
-                       sock_release(__icmpv6_socket[i]);
-                       __icmpv6_socket[i] = NULL;
-               }
-               return -EAGAIN;
+               err = -EAGAIN;
+               goto fail;
        }
 
        return 0;
+
+ fail:
+       for (j = 0; j < i; j++) {
+               if (!cpu_possible(j))
+                       continue;
+               sock_release(per_cpu(__icmpv6_socket, j));
+       }
+
+       return err;
 }
 
 void icmpv6_cleanup(void)
@@ -711,8 +708,7 @@
        for (i = 0; i < NR_CPUS; i++) {
                if (!cpu_possible(i))
                        continue;
-               sock_release(__icmpv6_socket[i]);
-               __icmpv6_socket[i] = NULL; /* For safety. */
+               sock_release(per_cpu(__icmpv6_socket, i));
        }
        inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 }