net: skb ftracer - add tracepoint to skb_copy_datagram_iovec (v3)

skb allocation / cosumption tracer - Add consumption tracepoint

This patch adds a tracepoint to skb_copy_datagram_iovec, which is called each
time a userspace process copies a frame from a socket receive queue to a user
space buffer.  It allows us to hook in and examine each sk_buff that the system
receives on a per-socket bases, and can be use to compile a list of which skb's
were received by which processes.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>

 include/trace/events/skb.h |   20 ++++++++++++++++++++
 net/core/datagram.c        |    3 +++
 2 files changed, 23 insertions(+)
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 23 insertions, 0 deletions

diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index e499863b9669..4b2be6dc76f0 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -5,6 +5,7 @@
 #define _TRACE_SKB_H
 
 #include <linux/skbuff.h>
+#include <linux/netdevice.h>
 #include <linux/tracepoint.h>
 
 /*
@@ -34,6 +35,25 @@ TRACE_EVENT(kfree_skb,
                 __entry->skbaddr, __entry->protocol, __entry->location)
 );
 
+TRACE_EVENT(skb_copy_datagram_iovec,
+
+        TP_PROTO(const struct sk_buff *skb, int len),
+
+        TP_ARGS(skb, len),
+
+        TP_STRUCT__entry(
+                __field(        const void *,           skbaddr         )
+                __field(        int,                    len             )
+        ),
+
+        TP_fast_assign(
+                __entry->skbaddr = skb;
+                __entry->len = len;
+        ),
+
+        TP_printk("skbaddr=%p len=%d", __entry->skbaddr, __entry->len)
+);
+
 #endif /* _TRACE_SKB_H */
 
 /* This part must be outside protection */
diff --git a/net/core/datagram.c b/net/core/datagram.c
index b0fe69211eef..1c6cf3a1a4f6 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -55,6 +55,7 @@
 #include <net/checksum.h>
 #include <net/sock.h>
 #include <net/tcp_states.h>
+#include <trace/events/skb.h>
 
 /*
  *      Is a socket 'connection oriented' ?
@@ -284,6 +285,8 @@ int skb_copy_datagram_iovec(const struct sk_buff *skb, int offset,
         int i, copy = start - offset;
         struct sk_buff *frag_iter;
 
+        trace_skb_copy_datagram_iovec(skb, len);
+
         /* Copy header. */
         if (copy > 0) {
                 if (copy > len)