[PATCH v2 net-next 2/2] net: sock: undefine SOCK_DEBUGGING

[Yafang Shao <laoar.shao@gmail.com>]

SOCK_DEBUG() is a old facility for debugging.
If the user want to use it for debugging, the user must modify the
application first, that doesn't seem like a good way.
Now we have more powerful facilities, i.e. bpf or tracepoint, for this kind
of debugging purpose.
So we'd better disable it by default.
The reason why I don't remove it comepletely is that someone may still
would like to use it for debugging.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Suggested-by: Joe Perches <joe@perches.com>
---
 include/net/sock.h | 13 ++++++++-----
 net/core/sock.c    |  3 +++
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 6679f3c..d41e8f4 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -81,14 +81,17 @@
  */
 
 /* Define this to get the SOCK_DBG debugging facility. */
-#define SOCK_DEBUGGING
+/* #define SOCK_DEBUGGING */
 #ifdef SOCK_DEBUGGING
-#define SOCK_DEBUG(sk, msg...) do { if ((sk) && sock_flag((sk), SOCK_DBG)) \
-					printk(KERN_DEBUG msg); } while (0)
+#define SOCK_DEBUG(sk, fmt, ...)		\
+do {						\
+	if ((sk) && sock_flag((sk), SOCK_DBG))	\
+		pr_debug(fmt, ##__VA_ARGS__);	\
+} while (0)
 #else
 /* Validate arguments and do nothing */
-static inline __printf(2, 3)
-void SOCK_DEBUG(const struct sock *sk, const char *msg, ...)
+__printf(2, 3)
+static inline void SOCK_DEBUG(const struct sock *sk, const char *fmt, ...)
 {
 }
 #endif
diff --git a/net/core/sock.c b/net/core/sock.c
index 71ded4d..7c15835 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -753,6 +753,9 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
 
 	switch (optname) {
 	case SO_DEBUG:
+		/* This option takes effect only when SOCK_DEBUGGING
+		 * is defined.
+		 */
 		if (val && !capable(CAP_NET_ADMIN))
 			ret = -EACCES;
 		else
-- 
1.8.3.1