rtnetlink: Replace implementation of ASSERT_RTNL() macro with WARN_ONCE()

From: Leon Romanovsky <[email protected]>

ASSERT_RTNL() macro is actual open-coded variant of WARN_ONCE() with two exceptions. First, it prints stack for multiple hits and not only once as WARN_ONCE() does. Second, the user can disable prints of WARN_ONCE by setting CONFIG_BUG to N.

The multiple prints of dump stack are actually not needed, because calls without rtnl lock are programming errors and user can't do anything about them except to complain to the mailing list after first occurrence of such failure.

The user who disabled BUG/WARN prints did it explicitly because by default in upstream kernel and distributions this option is enabled. It means that user doesn't want to see prints about missing locks too.

This patch replaces open-coded variant in favor of already existing macro and change error prints to be once only.

---
 include/linux/rtnetlink.h | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

index 2032ce2eb20b..62d508b31f56 100644
@@ -97,13 +97,9 @@ void rtnetlink_init(void);
 void __rtnl_unlock(void);
 void rtnl_kfree_skbs(struct sk_buff *head, struct sk_buff *tail);
 
-#define ASSERT_RTNL() do { \
-	if (unlikely(!rtnl_is_locked())) { \
-		printk(KERN_ERR "RTNL: assertion failed at %s (%d)\n", \
-		       __FILE__,  __LINE__); \
-		dump_stack(); \
-	} \
-} while(0)
+#define ASSERT_RTNL() \
+	WARN_ONCE(!rtnl_is_locked(), \
+		  "RTNL: assertion failed at %s (%d)\n", __FILE__,  __LINE__)
 
 extern int ndo_dflt_fdb_dump(struct sk_buff *skb,
 			     struct netlink_callback *cb,

From: Leon Romanovsky <[email protected]>
Date: Thu, 21 Dec 2017 11:40:04 +0200

Applied.