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icmp: icmp_send() can avoid a dev_put()

PATCH Applied Eric Dumazet 2 participants 2 messages Nov 2, 2009

Subsystems (3)
Networking Network drivers IPv4/IPv6
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Eric Dumazet

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PATCH 1/1 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 <[email protected]>

---

net/ipv4/icmp.c +5 -4
index 84adb57..fe11f60 100644
@@ -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) |