bug: consolidate __WARN_FLAGS usage

Instead of having separate tests for __WARN_FLAGS, merge the two #ifdef
blocks and replace the synonym WANT_WARN_ON_SLOWPATH macro.

Link: http://lkml.kernel.org/r/20190819234111.9019-7-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Drew Davenport <ddavenport@chromium.org>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-generic/bug.h

@@ -61,16 +61,6 @@ struct bug_entry {
 #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
 #endif
 
-#ifdef __WARN_FLAGS
-#define WARN_ON_ONCE(condition) ({				\
-	int __ret_warn_on = !!(condition);			\
-	if (unlikely(__ret_warn_on))				\
-		__WARN_FLAGS(BUGFLAG_ONCE |			\
-			     BUGFLAG_TAINT(TAINT_WARN));	\
-	unlikely(__ret_warn_on);				\
-})
-#endif
-
 /*
  * WARN(), WARN_ON(), WARN_ON_ONCE, and so on can be used to report
  * significant kernel issues that need prompt attention if they should ever
@@ -91,7 +81,6 @@ struct bug_entry {
 extern __printf(4, 5)
 void warn_slowpath_fmt(const char *file, const int line, unsigned taint,
 		       const char *fmt, ...);
-#define WANT_WARN_ON_SLOWPATH
 #define __WARN()		__WARN_printf(TAINT_WARN, NULL)
 #define __WARN_printf(taint, arg...)					\
 	warn_slowpath_fmt(__FILE__, __LINE__, taint, arg)
@@ -105,6 +94,13 @@ extern __printf(1, 2) void __warn_printk(const char *fmt, ...);
 		__warn_printk(arg);					\
 		__WARN_FLAGS(BUGFLAG_TAINT(taint));			\
 	} while (0)
+#define WARN_ON_ONCE(condition) ({				\
+	int __ret_warn_on = !!(condition);			\
+	if (unlikely(__ret_warn_on))				\
+		__WARN_FLAGS(BUGFLAG_ONCE |			\
+			     BUGFLAG_TAINT(TAINT_WARN));	\
+	unlikely(__ret_warn_on);				\
+})
 #endif
 
 /* used internally by panic.c */

kernel/panic.c

@@ -596,7 +596,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
 	add_taint(taint, LOCKDEP_STILL_OK);
 }
 
-#ifdef WANT_WARN_ON_SLOWPATH
+#ifndef __WARN_FLAGS
 void warn_slowpath_fmt(const char *file, int line, unsigned taint,
 		       const char *fmt, ...)
 {