From: Andrea Parri <andrea.parri@amarulasolutions.com>
To: linux-kernel@vger.kernel.org
Cc: Andrea Parri <andrea.parri@amarulasolutions.com>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jorgen Hansen <jhansen@vmware.com>,
Peter Zijlstra <peterz@infradead.org>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
"Paul E. McKenney" <paulmck@linux.ibm.com>
Subject: [PATCH 2/2] compiler: Prevent evaluation of WRITE_ONCE()
Date: Fri, 24 May 2019 12:35:36 +0200 [thread overview]
Message-ID: <1558694136-19226-3-git-send-email-andrea.parri@amarulasolutions.com> (raw)
In-Reply-To: <1558694136-19226-1-git-send-email-andrea.parri@amarulasolutions.com>
Now that there's no single use of the value of WRITE_ONCE(), change
the implementation to eliminate it.
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jorgen Hansen <jhansen@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: "Paul E. McKenney" <paulmck@linux.ibm.com>
---
include/linux/compiler.h | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 8aaf7cd026b06..4024c809a6c63 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -277,12 +277,11 @@ unsigned long read_word_at_a_time(const void *addr)
}
#define WRITE_ONCE(x, val) \
-({ \
+do { \
union { typeof(x) __val; char __c[1]; } __u = \
{ .__val = (__force typeof(x)) (val) }; \
__write_once_size(&(x), __u.__c, sizeof(x)); \
- __u.__val; \
-})
+} while (0)
#endif /* __KERNEL__ */
--
2.7.4
next prev parent reply other threads:[~2019-05-24 10:36 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-24 10:35 [PATCH 0/2] Prevent evaluation of WRITE_ONCE() Andrea Parri
2019-05-24 10:35 ` [PATCH 1/2] vmw_vmci: Clean up uses of atomic*_set() Andrea Parri
2019-05-24 10:39 ` Peter Zijlstra
2019-05-24 11:40 ` Greg Kroah-Hartman
2019-05-24 11:59 ` Andrea Parri
2019-05-24 11:56 ` Andrea Parri
2019-05-24 10:35 ` Andrea Parri [this message]
2019-05-24 10:53 ` [PATCH 2/2] compiler: Prevent evaluation of WRITE_ONCE() Mark Rutland
2019-05-24 11:24 ` Andrea Parri
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