[PATCH] asm-generic: bug: add unlikely() to BUG_ON()

From: Igor Stoppa
Date: Fri Sep 07 2018 - 15:21:32 EST


Add a hint to the compiler.
If BUG_ON() is used instead of BUG(), it means that probably the
preferred outcome is to not BUG().

The optimization is disabled, in case CONFIG_PROFILE_ANNOTATED_BRANCHES
is turned on.

Signed-off-by: Igor Stoppa <igor.stoppa@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
include/asm-generic/bug.h | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 20561a60db9c..bf47584eab2a 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -183,7 +183,11 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
#endif

#ifndef HAVE_ARCH_BUG_ON
+#ifdef CONFIG_PROFILE_ANNOTATED_BRANCHES
#define BUG_ON(condition) do { if (condition) BUG(); } while (0)
+#else
+#define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
+#endif
#endif

#ifndef HAVE_ARCH_WARN_ON
--
2.17.1