[PATCH v2 2/7] bug: Improve unlikely() in data corruption check

From	Kees Cook <keescook@chromium.org>
Newsgroups	linux.kernel
Subject	[PATCH v2 2/7] bug: Improve unlikely() in data corruption check
Date	2017-04-05 00:20 +0200
Message-ID	<tsEXU-2s7-33@gated-at.bofh.it> (permalink)
References	<tsEXT-2s7-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

This improves the compiler branch-hinting used in CHECK_DATA_CORRUPTION(),
similar to how it is done in WARN_ON() and friends.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 include/linux/bug.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/bug.h b/include/linux/bug.h
index db1e41c69bac..b6cfcb7f778f 100644
--- a/include/linux/bug.h
+++ b/include/linux/bug.h
@@ -130,15 +130,15 @@ static inline enum bug_trap_type report_bug(unsigned long bug_addr,
 static inline __must_check bool check_data_corruption(bool v) { return v; }
 #define CHECK_DATA_CORRUPTION(condition, fmt, ...)			 \
 	check_data_corruption(({					 \
-		bool corruption = unlikely(condition);			 \
-		if (corruption) {					 \
+		bool corruption = !!(condition);			 \
+		if (unlikely(corruption)) {				 \
 			if (IS_ENABLED(CONFIG_BUG_ON_DATA_CORRUPTION)) { \
 				pr_err(fmt, ##__VA_ARGS__);		 \
 				BUG();					 \
 			} else						 \
 				WARN(1, fmt, ##__VA_ARGS__);		 \
 		}							 \
-		corruption;						 \
+		unlikely(corruption);					 \
 	}))
 
 #endif	/* _LINUX_BUG_H */
-- 
2.7.4

Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

[PATCH v2] bug: further enhance use of CHECK_DATA_CORRUPTION Kees Cook <keescook@chromium.org> - 2017-04-05 00:20 +0200
  [PATCH v2 5/7] bug: Enable DEBUG_SG under BUG_ON_DATA_CORRUPTION Kees Cook <keescook@chromium.org> - 2017-04-05 00:20 +0200
  [PATCH v2 3/7] bug: Use WARN_ONCE() for CHECK_DATA_CORRUPTION() Kees Cook <keescook@chromium.org> - 2017-04-05 00:20 +0200
  [PATCH v2 2/7] bug: Improve unlikely() in data corruption check Kees Cook <keescook@chromium.org> - 2017-04-05 00:20 +0200

csiph-web