icmp: icmp_send() can avoid a dev_put()

We can avoid touching device refcount in icmp_send(),
using dev_get_by_index_rcu()

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

1 files changed, 5 insertions, 4 deletions

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 84adb5754c96..fe11f60ce41b 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -501,15 +501,16 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
         if (!(rt->rt_flags & RTCF_LOCAL)) {
                 struct net_device *dev = NULL;
 
+                rcu_read_lock();
                 if (rt->fl.iif &&
                         net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr)
-                        dev = dev_get_by_index(net, rt->fl.iif);
+                        dev = dev_get_by_index_rcu(net, rt->fl.iif);
 
-                if (dev) {
+                if (dev)
                         saddr = inet_select_addr(dev, 0, RT_SCOPE_LINK);
-                        dev_put(dev);
-                } else
+                else
                         saddr = 0;
+                rcu_read_unlock();
         }
 
         tos = icmp_pointers[type].error ? ((iph->tos & IPTOS_TOS_MASK) |