mptcp: add tracepoint in mptcp_sendmsg_frag

The tracepoint in get_mapping_status() only dumped the incoming mpext
fields. This patch added a new tracepoint in mptcp_sendmsg_frag() to dump
the outgoing mpext too.
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/trace/events/mptcp.h

@@ -115,6 +115,10 @@ DECLARE_EVENT_CLASS(mptcp_dump_mpext,
 		  __entry->csum_reqd)
 );
 
+DEFINE_EVENT(mptcp_dump_mpext, mptcp_sendmsg_frag,
+	TP_PROTO(struct mptcp_ext *mpext),
+	TP_ARGS(mpext));
+
 DEFINE_EVENT(mptcp_dump_mpext, get_mapping_status,
 	TP_PROTO(struct mptcp_ext *mpext),
 	TP_ARGS(mpext));

net/mptcp/protocol.c

@@ -1356,6 +1356,7 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
 out:
 	if (READ_ONCE(msk->csum_enabled))
 		mptcp_update_data_checksum(skb, copy);
+	trace_mptcp_sendmsg_frag(mpext);
 	mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
 	return copy;
 }