icmp: Remove some spurious dropped packet profile hits from the ICMP path

If icmp_rcv() has successfully processed the incoming ICMP datagram, we
should use consume_skb() rather than kfree_skb() because a hit on the likes
of perf -e skb:kfree_skb is not called-for.

Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 42 insertions, 21 deletions

diff --git a/include/net/ping.h b/include/net/ping.h
index 026479b61a2d..f074060bc5de 100644
--- a/include/net/ping.h
+++ b/include/net/ping.h
@@ -82,7 +82,7 @@ int  ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 int  ping_v6_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
                      size_t len);
 int  ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
-void ping_rcv(struct sk_buff *skb);
+bool ping_rcv(struct sk_buff *skb);
 
 #ifdef CONFIG_PROC_FS
 struct ping_seq_afinfo {
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 36b7bfa609d6..36f5584d93c5 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -190,7 +190,7 @@ EXPORT_SYMBOL(icmp_err_convert);
  */
 
 struct icmp_control {
-        void (*handler)(struct sk_buff *skb);
+        bool (*handler)(struct sk_buff *skb);
         short   error;          /* This ICMP is classed as an error message */
 };
 
@@ -746,7 +746,7 @@ static bool icmp_tag_validation(int proto)
  *      ICMP_PARAMETERPROB.
  */
 
-static void icmp_unreach(struct sk_buff *skb)
+static bool icmp_unreach(struct sk_buff *skb)
 {
         const struct iphdr *iph;
         struct icmphdr *icmph;
@@ -839,10 +839,10 @@ static void icmp_unreach(struct sk_buff *skb)
         icmp_socket_deliver(skb, info);
 
 out:
-        return;
+        return true;
 out_err:
         ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
-        goto out;
+        return false;
 }
 
 
@@ -850,17 +850,20 @@ out_err:
  *      Handle ICMP_REDIRECT.
  */
 
-static void icmp_redirect(struct sk_buff *skb)
+static bool icmp_redirect(struct sk_buff *skb)
 {
         if (skb->len < sizeof(struct iphdr)) {
                 ICMP_INC_STATS_BH(dev_net(skb->dev), ICMP_MIB_INERRORS);
-                return;
+                return false;
         }
 
-        if (!pskb_may_pull(skb, sizeof(struct iphdr)))
-                return;
+        if (!pskb_may_pull(skb, sizeof(struct iphdr))) {
+                /* there aught to be a stat */
+                return false;
+        }
 
         icmp_socket_deliver(skb, icmp_hdr(skb)->un.gateway);
+        return true;
 }
 
 /*
@@ -875,7 +878,7 @@ static void icmp_redirect(struct sk_buff *skb)
  *      See also WRT handling of options once they are done and working.
  */
 
-static void icmp_echo(struct sk_buff *skb)
+static bool icmp_echo(struct sk_buff *skb)
 {
         struct net *net;
 
@@ -891,6 +894,8 @@ static void icmp_echo(struct sk_buff *skb)
                 icmp_param.head_len        = sizeof(struct icmphdr);
                 icmp_reply(&icmp_param, skb);
         }
+        /* should there be an ICMP stat for ignored echos? */
+        return true;
 }
 
 /*
@@ -900,7 +905,7 @@ static void icmp_echo(struct sk_buff *skb)
  *                MUST be accurate to a few minutes.
  *                MUST be updated at least at 15Hz.
  */
-static void icmp_timestamp(struct sk_buff *skb)
+static bool icmp_timestamp(struct sk_buff *skb)
 {
         struct timespec tv;
         struct icmp_bxm icmp_param;
@@ -927,15 +932,17 @@ static void icmp_timestamp(struct sk_buff *skb)
         icmp_param.data_len        = 0;
         icmp_param.head_len        = sizeof(struct icmphdr) + 12;
         icmp_reply(&icmp_param, skb);
-out:
-        return;
+        return true;
+
 out_err:
         ICMP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS);
-        goto out;
+        return false;
 }
 
-static void icmp_discard(struct sk_buff *skb)
+static bool icmp_discard(struct sk_buff *skb)
 {
+        /* pretend it was a success */
+        return true;
 }
 
 /*
@@ -946,6 +953,7 @@ int icmp_rcv(struct sk_buff *skb)
         struct icmphdr *icmph;
         struct rtable *rt = skb_rtable(skb);
         struct net *net = dev_net(rt->dst.dev);
+        bool success;
 
         if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
                 struct sec_path *sp = skb_sec_path(skb);
@@ -1012,7 +1020,12 @@ int icmp_rcv(struct sk_buff *skb)
                 }
         }
 
-        icmp_pointers[icmph->type].handler(skb);
+        success = icmp_pointers[icmph->type].handler(skb);
+
+        if (success)  {
+                consume_skb(skb);
+                return 0;
+        }
 
 drop:
         kfree_skb(skb);
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 736236c3e554..ce2920f5bef3 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -955,7 +955,7 @@ EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
  *      All we need to do is get the socket.
  */
 
-void ping_rcv(struct sk_buff *skb)
+bool ping_rcv(struct sk_buff *skb)
 {
         struct sock *sk;
         struct net *net = dev_net(skb->dev);
@@ -974,11 +974,11 @@ void ping_rcv(struct sk_buff *skb)
                 pr_debug("rcv on socket %p\n", sk);
                 ping_queue_rcv_skb(sk, skb_get(skb));
                 sock_put(sk);
-                return;
+                return true;
         }
         pr_debug("no socket, dropping\n");
 
-        /* We're called from icmp_rcv(). kfree_skb() is done there. */
+        return false;
 }
 EXPORT_SYMBOL_GPL(ping_rcv);
 
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 092934032077..39b3ff97a504 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -679,6 +679,7 @@ static int icmpv6_rcv(struct sk_buff *skb)
         const struct in6_addr *saddr, *daddr;
         struct icmp6hdr *hdr;
         u8 type;
+        bool success = false;
 
         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
                 struct sec_path *sp = skb_sec_path(skb);
@@ -726,7 +727,7 @@ static int icmpv6_rcv(struct sk_buff *skb)
                 break;
 
         case ICMPV6_ECHO_REPLY:
-                ping_rcv(skb);
+                success = ping_rcv(skb);
                 break;
 
         case ICMPV6_PKT_TOOBIG:
@@ -790,7 +791,14 @@ static int icmpv6_rcv(struct sk_buff *skb)
                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
         }
 
-        kfree_skb(skb);
+        /* until the v6 path can be better sorted assume failure and
+         * preserve the status quo behaviour for the rest of the paths to here
+         */
+        if (success)
+                consume_skb(skb);
+        else
+                kfree_skb(skb);
+
         return 0;
 
 csum_error: