net: Use ip_route_input_noref() in input path

Use ip_route_input_noref() in ip fast path, to avoid two atomic ops per
incoming packet.

Note: loopback is excluded from this optimization in ip_rcv_finish()

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

3 files changed, 5 insertions, 5 deletions

diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 80769f1f9fab..f094b75810db 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -854,7 +854,7 @@ static int arp_process(struct sk_buff *skb)
         }
 
         if (arp->ar_op == htons(ARPOP_REQUEST) &&
-            ip_route_input(skb, tip, sip, 0, dev) == 0) {
+            ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
 
                 rt = skb_rtable(skb);
                 addr_type = rt->rt_type;
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index af76de5f76de..d930dc5e4d85 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -331,8 +331,8 @@ static int ip_rcv_finish(struct sk_buff *skb)
          *      how the packet travels inside Linux networking.
          */
         if (skb_dst(skb) == NULL) {
-                int err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
-                                         skb->dev);
+                int err = ip_route_input_noref(skb, iph->daddr, iph->saddr,
+                                               iph->tos, skb->dev);
                 if (unlikely(err)) {
                         if (err == -EHOSTUNREACH)
                                 IP_INC_STATS_BH(dev_net(skb->dev),
diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index abcd7ed65db1..ad8fbb871aa0 100644
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -27,8 +27,8 @@ static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
         if (skb_dst(skb) == NULL) {
                 const struct iphdr *iph = ip_hdr(skb);
 
-                if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
-                                   skb->dev))
+                if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
+                                         iph->tos, skb->dev))
                         goto drop;
         }
         return dst_input(skb);