* Re: [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire
[not found] <1438528264-714-1-git-send-email-andreyknvl@google.com>
@ 2015-08-02 16:08 ` Peter Zijlstra
2015-08-02 20:50 ` Davidlohr Bueso
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Peter Zijlstra @ 2015-08-02 16:08 UTC (permalink / raw)
To: Andrey Konovalov
Cc: Russell King, Catalin Marinas, Will Deacon, Tony Luck, Fenghua Yu,
James Hogan, Ralf Baechle, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Martin Schwidefsky, Heiko Carstens, linux390,
David S. Miller, Thomas Gleixner, Ingo Molnar, H. Peter Anvin,
x86, Arnd Bergmann, Alexander Duyck, Andre Przywara,
Paul E. McKenney, Borislav Petkov, linux-arm-kernel
On Sun, Aug 02, 2015 at 05:11:04PM +0200, Andrey Konovalov wrote:
> Replace ACCESS_ONCE() macro in smp_store_release() and smp_load_acquire()
> with WRITE_ONCE() and READ_ONCE() on x86, arm, arm64, ia64, metag, mips,
> powerpc, s390, sparc and asm-generic since ACCESS_ONCE does not work
> reliably on non-scalar types.
>
> WRITE_ONCE() and READ_ONCE() were introduced in the commits 230fa253df63
> ("kernel: Provide READ_ONCE and ASSIGN_ONCE") and 43239cbe79fc ("kernel:
> Change ASSIGN_ONCE(val, x) to WRITE_ONCE(x, val)").
>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Thanks!
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire
[not found] <1438528264-714-1-git-send-email-andreyknvl@google.com>
2015-08-02 16:08 ` [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire Peter Zijlstra
@ 2015-08-02 20:50 ` Davidlohr Bueso
2015-08-03 1:41 ` Michael Ellerman
2015-08-03 6:02 ` Ralf Baechle
3 siblings, 0 replies; 5+ messages in thread
From: Davidlohr Bueso @ 2015-08-02 20:50 UTC (permalink / raw)
To: Andrey Konovalov
Cc: Russell King, Catalin Marinas, Will Deacon, Tony Luck, Fenghua Yu,
James Hogan, Ralf Baechle, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Martin Schwidefsky, Heiko Carstens, linux390,
David S. Miller, Thomas Gleixner, Ingo Molnar, H. Peter Anvin,
x86, Arnd Bergmann, Peter Zijlstra, Alexander Duyck,
Andre Przywara, Paul E. McKenney, Borislav
On Sun, 2015-08-02 at 17:11 +0200, Andrey Konovalov wrote:
> Replace ACCESS_ONCE() macro in smp_store_release() and smp_load_acquire()
> with WRITE_ONCE() and READ_ONCE() on x86, arm, arm64, ia64, metag, mips,
> powerpc, s390, sparc and asm-generic since ACCESS_ONCE does not work
> reliably on non-scalar types.
>
> WRITE_ONCE() and READ_ONCE() were introduced in the commits 230fa253df63
> ("kernel: Provide READ_ONCE and ASSIGN_ONCE") and 43239cbe79fc ("kernel:
> Change ASSIGN_ONCE(val, x) to WRITE_ONCE(x, val)").
>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire
[not found] <1438528264-714-1-git-send-email-andreyknvl@google.com>
2015-08-02 16:08 ` [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire Peter Zijlstra
2015-08-02 20:50 ` Davidlohr Bueso
@ 2015-08-03 1:41 ` Michael Ellerman
2015-08-03 6:02 ` Ralf Baechle
3 siblings, 0 replies; 5+ messages in thread
From: Michael Ellerman @ 2015-08-03 1:41 UTC (permalink / raw)
To: Andrey Konovalov
Cc: Russell King, Catalin Marinas, Will Deacon, Tony Luck, Fenghua Yu,
James Hogan, Ralf Baechle, Benjamin Herrenschmidt, Paul Mackerras,
Martin Schwidefsky, Heiko Carstens, linux390, David S. Miller,
Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86, Arnd Bergmann,
Peter Zijlstra, Alexander Duyck, Andre Przywara, Paul E. McKenney,
Borislav Petkov, linux-arm-kernel
On Sun, 2015-08-02 at 17:11 +0200, Andrey Konovalov wrote:
> Replace ACCESS_ONCE() macro in smp_store_release() and smp_load_acquire()
> with WRITE_ONCE() and READ_ONCE() on x86, arm, arm64, ia64, metag, mips,
> powerpc, s390, sparc and asm-generic since ACCESS_ONCE does not work
> reliably on non-scalar types.
.. and there are no restrictions on the argument to smp_load_acquire(), so it
may be a non-scalar type.
Though from a quick grep it looks like no one is doing that at the moment?
> WRITE_ONCE() and READ_ONCE() were introduced in the commits 230fa253df63
> ("kernel: Provide READ_ONCE and ASSIGN_ONCE") and 43239cbe79fc ("kernel:
> Change ASSIGN_ONCE(val, x) to WRITE_ONCE(x, val)").
>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> ---
> Changed in v2:
> - Other archs besides x86.
>
> arch/powerpc/include/asm/barrier.h | 4 ++--
> diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h
> index 51ccc72..0eca6ef 100644
> --- a/arch/powerpc/include/asm/barrier.h
> +++ b/arch/powerpc/include/asm/barrier.h
> @@ -76,12 +76,12 @@
> do { \
> compiletime_assert_atomic_type(*p); \
> smp_lwsync(); \
> - ACCESS_ONCE(*p) = (v); \
> + WRITE_ONCE(*p, v); \
> } while (0)
>
> #define smp_load_acquire(p) \
> ({ \
> - typeof(*p) ___p1 = ACCESS_ONCE(*p); \
> + typeof(*p) ___p1 = READ_ONCE(*p); \
> compiletime_assert_atomic_type(*p); \
> smp_lwsync(); \
> ___p1; \
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
cheers
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire
[not found] <1438528264-714-1-git-send-email-andreyknvl@google.com>
` (2 preceding siblings ...)
2015-08-03 1:41 ` Michael Ellerman
@ 2015-08-03 6:02 ` Ralf Baechle
3 siblings, 0 replies; 5+ messages in thread
From: Ralf Baechle @ 2015-08-03 6:02 UTC (permalink / raw)
To: Andrey Konovalov
Cc: Russell King, Catalin Marinas, Will Deacon, Tony Luck, Fenghua Yu,
James Hogan, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Martin Schwidefsky, Heiko Carstens, linux390,
David S. Miller, Thomas Gleixner, Ingo Molnar, H. Peter Anvin,
x86, Arnd Bergmann, Peter Zijlstra, Alexander Duyck,
Andre Przywara, Paul E. McKenney, Borislav Petkov,
linux-arm-kernel
On Sun, Aug 02, 2015 at 05:11:04PM +0200, Andrey Konovalov wrote:
> diff --git a/arch/mips/include/asm/barrier.h b/arch/mips/include/asm/barrier.h
> index 7ecba84..752e0b8 100644
> --- a/arch/mips/include/asm/barrier.h
> +++ b/arch/mips/include/asm/barrier.h
> @@ -133,12 +133,12 @@
> do { \
> compiletime_assert_atomic_type(*p); \
> smp_mb(); \
> - ACCESS_ONCE(*p) = (v); \
> + WRITE_ONCE(*p, v); \
> } while (0)
>
> #define smp_load_acquire(p) \
> ({ \
> - typeof(*p) ___p1 = ACCESS_ONCE(*p); \
> + typeof(*p) ___p1 = READ_ONCE(*p); \
> compiletime_assert_atomic_type(*p); \
> smp_mb(); \
> ___p1; \
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Ralf
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire
@ 2015-08-02 15:11 Andrey Konovalov
0 siblings, 0 replies; 5+ messages in thread
From: Andrey Konovalov @ 2015-08-02 15:11 UTC (permalink / raw)
To: Russell King, Catalin Marinas, Will Deacon, Tony Luck, Fenghua Yu,
James Hogan, Ralf Baechle, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Martin Schwidefsky, Heiko Carstens,
linux390-tA70FqPdS9bQT0dZR+AlfA, David S. Miller, Thomas Gleixner,
Ingo Molnar, H. Peter Anvin, x86-DgEjT+Ai2ygdnm+yROfE0A,
Arnd Bergmann, Peter Zijlstra, Alexander Duyck, Andre Przywara,
Paul E. McKenney, Borislav
Cc: Andrey Konovalov, Dmitry Vyukov, Christian Borntraeger,
Davidlohr Bueso
Replace ACCESS_ONCE() macro in smp_store_release() and smp_load_acquire()
with WRITE_ONCE() and READ_ONCE() on x86, arm, arm64, ia64, metag, mips,
powerpc, s390, sparc and asm-generic since ACCESS_ONCE does not work
reliably on non-scalar types.
WRITE_ONCE() and READ_ONCE() were introduced in the commits 230fa253df63
("kernel: Provide READ_ONCE and ASSIGN_ONCE") and 43239cbe79fc ("kernel:
Change ASSIGN_ONCE(val, x) to WRITE_ONCE(x, val)").
Signed-off-by: Andrey Konovalov <andreyknvl-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
---
Changed in v2:
- Other archs besides x86.
arch/arm/include/asm/barrier.h | 4 ++--
arch/arm64/include/asm/barrier.h | 4 ++--
arch/ia64/include/asm/barrier.h | 4 ++--
arch/metag/include/asm/barrier.h | 4 ++--
arch/mips/include/asm/barrier.h | 4 ++--
arch/powerpc/include/asm/barrier.h | 4 ++--
arch/s390/include/asm/barrier.h | 4 ++--
arch/sparc/include/asm/barrier_64.h | 4 ++--
arch/x86/include/asm/barrier.h | 8 ++++----
include/asm-generic/barrier.h | 4 ++--
10 files changed, 22 insertions(+), 22 deletions(-)
diff --git a/arch/arm/include/asm/barrier.h b/arch/arm/include/asm/barrier.h
index 6c2327e..7039357 100644
--- a/arch/arm/include/asm/barrier.h
+++ b/arch/arm/include/asm/barrier.h
@@ -67,12 +67,12 @@
do { \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
___p1; \
diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h
index 0fa47c4..ef93b20 100644
--- a/arch/arm64/include/asm/barrier.h
+++ b/arch/arm64/include/asm/barrier.h
@@ -44,12 +44,12 @@
do { \
compiletime_assert_atomic_type(*p); \
barrier(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
barrier(); \
___p1; \
diff --git a/arch/ia64/include/asm/barrier.h b/arch/ia64/include/asm/barrier.h
index 843ba43..df896a1 100644
--- a/arch/ia64/include/asm/barrier.h
+++ b/arch/ia64/include/asm/barrier.h
@@ -66,12 +66,12 @@
do { \
compiletime_assert_atomic_type(*p); \
barrier(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
barrier(); \
___p1; \
diff --git a/arch/metag/include/asm/barrier.h b/arch/metag/include/asm/barrier.h
index 5a696e5..172b7e5 100644
--- a/arch/metag/include/asm/barrier.h
+++ b/arch/metag/include/asm/barrier.h
@@ -90,12 +90,12 @@ static inline void fence(void)
do { \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
___p1; \
diff --git a/arch/mips/include/asm/barrier.h b/arch/mips/include/asm/barrier.h
index 7ecba84..752e0b8 100644
--- a/arch/mips/include/asm/barrier.h
+++ b/arch/mips/include/asm/barrier.h
@@ -133,12 +133,12 @@
do { \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
___p1; \
diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h
index 51ccc72..0eca6ef 100644
--- a/arch/powerpc/include/asm/barrier.h
+++ b/arch/powerpc/include/asm/barrier.h
@@ -76,12 +76,12 @@
do { \
compiletime_assert_atomic_type(*p); \
smp_lwsync(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_lwsync(); \
___p1; \
diff --git a/arch/s390/include/asm/barrier.h b/arch/s390/include/asm/barrier.h
index e6f8615..d48fe01 100644
--- a/arch/s390/include/asm/barrier.h
+++ b/arch/s390/include/asm/barrier.h
@@ -42,12 +42,12 @@
do { \
compiletime_assert_atomic_type(*p); \
barrier(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
barrier(); \
___p1; \
diff --git a/arch/sparc/include/asm/barrier_64.h b/arch/sparc/include/asm/barrier_64.h
index 809941e..14a9286 100644
--- a/arch/sparc/include/asm/barrier_64.h
+++ b/arch/sparc/include/asm/barrier_64.h
@@ -60,12 +60,12 @@ do { __asm__ __volatile__("ba,pt %%xcc, 1f\n\t" \
do { \
compiletime_assert_atomic_type(*p); \
barrier(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
barrier(); \
___p1; \
diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index e51a8f8..d2bcfbe 100644
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -57,12 +57,12 @@
do { \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
___p1; \
@@ -74,12 +74,12 @@ do { \
do { \
compiletime_assert_atomic_type(*p); \
barrier(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
barrier(); \
___p1; \
diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h
index 55e3abc..b42afad 100644
--- a/include/asm-generic/barrier.h
+++ b/include/asm-generic/barrier.h
@@ -108,12 +108,12 @@
do { \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
___p1; \
--
2.5.0.rc2.392.g76e840b
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2015-08-02 16:08 ` [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire Peter Zijlstra
2015-08-02 20:50 ` Davidlohr Bueso
2015-08-03 1:41 ` Michael Ellerman
2015-08-03 6:02 ` Ralf Baechle
2015-08-02 15:11 Andrey Konovalov
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