ipv6: no more dev_put() in datagram_send_ctl()
Eric Dumazet [Mon, 2 Nov 2009 11:21:06 +0000 (12:21 +0100)]
Avoids touching device refcount in datagram_send_ctl(), thanks to RCU

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

net/ipv6/datagram.c

index 9f70452..e6f9cdf 100644 (file)
@@ -537,12 +537,17 @@ int datagram_send_ctl(struct net *net,
 
                        addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
 
+                       rcu_read_lock();
                        if (fl->oif) {
-                               dev = dev_get_by_index(net, fl->oif);
-                               if (!dev)
+                               dev = dev_get_by_index_rcu(net, fl->oif);
+                               if (!dev) {
+                                       rcu_read_unlock();
                                        return -ENODEV;
-                       } else if (addr_type & IPV6_ADDR_LINKLOCAL)
+                               }
+                       } else if (addr_type & IPV6_ADDR_LINKLOCAL) {
+                               rcu_read_unlock();
                                return -EINVAL;
+                       }
 
                        if (addr_type != IPV6_ADDR_ANY) {
                                int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
@@ -553,8 +558,7 @@ int datagram_send_ctl(struct net *net,
                                        ipv6_addr_copy(&fl->fl6_src, &src_info->ipi6_addr);
                        }
 
-                       if (dev)
-                               dev_put(dev);
+                       rcu_read_unlock();
 
                        if (err)
                                goto exit_f;