Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Fri, 15 May 2020 17:03:36 +0200
In-Reply-To: <20200515150338.190344-1-elver@google.com>
Message-Id: <20200515150338.190344-9-elver@google.com>
Mime-Version: 1.0
References: <20200515150338.190344-1-elver@google.com>
Subject: [PATCH -tip 08/10] READ_ONCE, WRITE_ONCE: Remove data_race() wrapping
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
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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