1 files changed, 20 insertions, 4 deletions

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 4c794d73fb84..37b82cb96c89 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -28,6 +28,17 @@ struct bug_entry {
 #define BUGFLAG_WARNING (1<<0)
 #endif  /* CONFIG_GENERIC_BUG */
 
+/*
+ * Don't use BUG() or BUG_ON() unless there's really no way out; one
+ * example might be detecting data structure corruption in the middle
+ * of an operation that can't be backed out of.  If the (sub)system
+ * can somehow continue operating, perhaps with reduced functionality,
+ * it's probably not BUG-worthy.
+ *
+ * If you're tempted to BUG(), think again:  is completely giving up
+ * really the *only* solution?  There are usually better options, where
+ * users don't need to reboot ASAP and can mostly shut down cleanly.
+ */
 #ifndef HAVE_ARCH_BUG
 #define BUG() do { \
         printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
@@ -39,17 +50,22 @@ struct bug_entry {
 #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while(0)
 #endif
 
+/*
+ * WARN(), WARN_ON(), WARN_ON_ONCE, and so on can be used to report
+ * significant issues that need prompt attention if they should ever
+ * appear at runtime.  Use the versions with printk format strings
+ * to provide better diagnostics.
+ */
 #ifndef __WARN
 #ifndef __ASSEMBLY__
-extern void warn_on_slowpath(const char *file, const int line);
 extern void warn_slowpath(const char *file, const int line,
                 const char *fmt, ...) __attribute__((format(printf, 3, 4)));
 #define WANT_WARN_ON_SLOWPATH
 #endif
-#define __WARN() warn_on_slowpath(__FILE__, __LINE__)
-#define __WARN_printf(arg...) warn_slowpath(__FILE__, __LINE__, arg)
+#define __WARN()                warn_slowpath(__FILE__, __LINE__, NULL)
+#define __WARN_printf(arg...)   warn_slowpath(__FILE__, __LINE__, arg)
 #else
-#define __WARN_printf(arg...) do { printk(arg); __WARN(); } while (0)
+#define __WARN_printf(arg...)   do { printk(arg); __WARN(); } while (0)
 #endif
 
 #ifndef WARN_ON