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From: Chih-En Lin <shiyn.lin@gmail.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Borislav Petkov <bp@suse.de>, Don Zickus <dzickus@redhat.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Stephane Eranian <eranian@google.com>,
	linux-kernel@vger.kernel.org,
	asas1asas200 <asas1asas200@gmail.com>,
	Huichun Feng <foxhoundsk.tw@gmail.com>,
	Jim Huang <jserv@ccns.ncku.edu.tw>,
	Chih-En Lin <shiyn.lin@gmail.com>
Subject: [PATCH] tools: Upgrade atomic_set() to use WRITE_ONCE()
Date: Tue, 12 Jul 2022 01:08:51 +0800	[thread overview]
Message-ID: <20220711170851.72208-1-shiyn.lin@gmail.com> (raw)

Since the atomic operation in the tools directory is from the kernel
source [1]. And from the commit [2], atomic_set() is at least
WRITE_ONCE() in the kernel source. atomic_{read,set}() should be
symmetry with {READ, WRITE}_ONCE() [3]. To be synchronous with the
source, atomic_set() should use WRITE_ONCE() rather than plain access.

[1] commit da6d8567512d ("tools include: Add basic atomic.h implementation from the kernel sources")
[2] commit 62e8a3258bda ("atomic, arch: Audit atomic_{read,set}()")
[3] commit 6aa7de059173 ("locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()")

Signed-off-by: asas1asas200 <asas1asas200@gmail.com>
Signed-off-by: Chih-En Lin <shiyn.lin@gmail.com>
---
 tools/arch/x86/include/asm/atomic.h    | 2 +-
 tools/include/asm-generic/atomic-gcc.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/arch/x86/include/asm/atomic.h b/tools/arch/x86/include/asm/atomic.h
index 1f5e26aae9fc..4dcf4e9baecc 100644
--- a/tools/arch/x86/include/asm/atomic.h
+++ b/tools/arch/x86/include/asm/atomic.h
@@ -37,7 +37,7 @@ static inline int atomic_read(const atomic_t *v)
  */
 static inline void atomic_set(atomic_t *v, int i)
 {
-	v->counter = i;
+	WRITE_ONCE(v->counter, i);
 }
 
 /**
diff --git a/tools/include/asm-generic/atomic-gcc.h b/tools/include/asm-generic/atomic-gcc.h
index 4c1966f7c77a..df84af8012e6 100644
--- a/tools/include/asm-generic/atomic-gcc.h
+++ b/tools/include/asm-generic/atomic-gcc.h
@@ -34,7 +34,7 @@ static inline int atomic_read(const atomic_t *v)
  */
 static inline void atomic_set(atomic_t *v, int i)
 {
-        v->counter = i;
+	WRITE_ONCE(v->counter, i);
 }
 
 /**
-- 
2.25.1


                 reply	other threads:[~2022-07-11 17:09 UTC|newest]

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