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From: Marco Elver <elver@google.com>
To: elver@google.com
Cc: paulmck@kernel.org, dvyukov@google.com, glider@google.com,
	andreyknvl@google.com, kasan-dev@googlegroups.com,
	linux-kernel@vger.kernel.org, tglx@linutronix.de,
	mingo@kernel.org, peterz@infradead.org, will@kernel.org,
	clang-built-linux@googlegroups.com
Subject: [PATCH -tip 08/10] READ_ONCE, WRITE_ONCE: Remove data_race() wrapping
Date: Fri, 15 May 2020 17:03:36 +0200	[thread overview]
Message-ID: <20200515150338.190344-9-elver@google.com> (raw)
In-Reply-To: <20200515150338.190344-1-elver@google.com>

The volatile access no longer needs to be wrapped in data_race(),
because we require compilers that emit instrumentation distinguishing
volatile accesses.

Signed-off-by: Marco Elver <elver@google.com>
---
 include/linux/compiler.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 17c98b215572..fce56402c082 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -229,7 +229,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 #define __READ_ONCE_SCALAR(x)						\
 ({									\
 	typeof(x) *__xp = &(x);						\
-	__unqual_scalar_typeof(x) __x = data_race(__READ_ONCE(*__xp));	\
+	__unqual_scalar_typeof(x) __x = __READ_ONCE(*__xp);		\
 	kcsan_check_atomic_read(__xp, sizeof(*__xp));			\
 	smp_read_barrier_depends();					\
 	(typeof(x))__x;							\
@@ -250,7 +250,7 @@ do {									\
 do {									\
 	typeof(x) *__xp = &(x);						\
 	kcsan_check_atomic_write(__xp, sizeof(*__xp));			\
-	data_race(({ __WRITE_ONCE(*__xp, val); 0; }));			\
+	__WRITE_ONCE(*__xp, val);					\
 } while (0)
 
 #define WRITE_ONCE(x, val)						\
-- 
2.26.2.761.g0e0b3e54be-goog


  parent reply	other threads:[~2020-05-15 15:04 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-15 15:03 [PATCH -tip 00/10] Fix KCSAN for new ONCE (require Clang 11) Marco Elver
2020-05-15 15:03 ` [PATCH -tip 01/10] ubsan, kcsan: don't combine sanitizer with kcov on clang Marco Elver
2020-05-15 15:03 ` [PATCH -tip 02/10] kcsan: Avoid inserting __tsan_func_entry/exit if possible Marco Elver
2020-05-15 15:03 ` [PATCH -tip 03/10] kcsan: Support distinguishing volatile accesses Marco Elver
2020-05-15 15:03 ` [PATCH -tip 04/10] kcsan: Pass option tsan-instrument-read-before-write to Clang Marco Elver
2020-05-15 15:03 ` [PATCH -tip 05/10] kcsan: Remove 'noinline' from __no_kcsan_or_inline Marco Elver
2020-05-15 15:03 ` [PATCH -tip 06/10] kcsan: Restrict supported compilers Marco Elver
2020-05-15 15:03 ` [PATCH -tip 07/10] kcsan: Update Documentation to change " Marco Elver
2020-05-15 15:03 ` Marco Elver [this message]
2020-05-21  9:47   ` [PATCH -tip 08/10] READ_ONCE, WRITE_ONCE: Remove data_race() wrapping Marco Elver
2020-05-21 10:18     ` Marco Elver
2020-05-21 10:22       ` Will Deacon
2020-05-15 15:03 ` [PATCH -tip 09/10] compiler.h: Move function attributes to compiler_types.h Marco Elver
2020-05-15 15:03 ` [PATCH -tip 10/10] compiler_types.h, kasan: Use __SANITIZE_ADDRESS__ instead of CONFIG_KASAN to decide inlining Marco Elver
2020-05-21 11:11 ` [PATCH -tip 00/10] Fix KCSAN for new ONCE (require Clang 11) Marco Elver

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