From 4f9e1ba6de45aa8797a83f1fe5b82ec4bac16899 Mon Sep 17 00:00:00 2001
From: Jeremy Kerr <jk@codeconstruct.com.au>
Date: Wed, 29 Sep 2021 15:26:10 +0800
Subject: mctp: Add tracepoints for tag/key handling

The tag allocation, release and bind events are somewhat opaque outside
the kernel; this change adds a few tracepoints to assist in
instrumentation and debugging.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/mctp/af_mctp.c |  6 ++++++
 net/mctp/route.c   | 12 +++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

(limited to 'net/mctp')

diff --git a/net/mctp/af_mctp.c b/net/mctp/af_mctp.c
index 46e5ede385cb..28cb1633bed6 100644
--- a/net/mctp/af_mctp.c
+++ b/net/mctp/af_mctp.c
@@ -16,6 +16,9 @@
 #include <net/mctpdevice.h>
 #include <net/sock.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/mctp.h>
+
 /* socket implementation */
 
 static int mctp_release(struct socket *sock)
@@ -239,6 +242,7 @@ static void mctp_sk_expire_keys(struct timer_list *timer)
 		spin_lock(&key->lock);
 
 		if (!time_after_eq(key->expiry, jiffies)) {
+			trace_mctp_key_release(key, MCTP_TRACE_KEY_TIMEOUT);
 			key->valid = false;
 			hlist_del_rcu(&key->hlist);
 			hlist_del_rcu(&key->sklist);
@@ -310,6 +314,8 @@ static void mctp_sk_unhash(struct sock *sk)
 		hlist_del(&key->sklist);
 		hlist_del(&key->hlist);
 
+		trace_mctp_key_release(key, MCTP_TRACE_KEY_CLOSED);
+
 		spin_lock(&key->lock);
 		if (key->reasm_head)
 			kfree_skb(key->reasm_head);
diff --git a/net/mctp/route.c b/net/mctp/route.c
index c342adf4f97f..acc5bb39e16d 100644
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -23,10 +23,11 @@
 #include <net/netlink.h>
 #include <net/sock.h>
 
+#include <trace/events/mctp.h>
+
 static const unsigned int mctp_message_maxlen = 64 * 1024;
 static const unsigned long mctp_key_lifetime = 6 * CONFIG_HZ;
 
-
 /* route output callbacks */
 static int mctp_route_discard(struct mctp_route *route, struct sk_buff *skb)
 {
@@ -332,6 +333,8 @@ static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
 				/* we've hit a pending reassembly; not much we
 				 * can do but drop it
 				 */
+				trace_mctp_key_release(key,
+						       MCTP_TRACE_KEY_REPLIED);
 				__mctp_key_unlock_drop(key, net, f);
 				key = NULL;
 			}
@@ -365,12 +368,16 @@ static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
 			if (rc)
 				kfree(key);
 
+			trace_mctp_key_acquire(key);
+
 			/* we don't need to release key->lock on exit */
 			key = NULL;
 
 		} else {
 			if (key->reasm_head || key->reasm_dead) {
 				/* duplicate start? drop everything */
+				trace_mctp_key_release(key,
+						       MCTP_TRACE_KEY_INVALIDATED);
 				__mctp_key_unlock_drop(key, net, f);
 				rc = -EEXIST;
 				key = NULL;
@@ -396,6 +403,7 @@ static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
 		if (!rc && flags & MCTP_HDR_FLAG_EOM) {
 			sock_queue_rcv_skb(key->sk, key->reasm_head);
 			key->reasm_head = NULL;
+			trace_mctp_key_release(key, MCTP_TRACE_KEY_REPLIED);
 			__mctp_key_unlock_drop(key, net, f);
 			key = NULL;
 		}
@@ -572,6 +580,8 @@ static int mctp_alloc_local_tag(struct mctp_sock *msk,
 	if (tagbits) {
 		key->tag = __ffs(tagbits);
 		mctp_reserve_tag(net, key, msk);
+		trace_mctp_key_acquire(key);
+
 		*tagp = key->tag;
 		rc = 0;
 	}
-- 
cgit