* Re: [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire
2015-08-02 15:11 [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire Andrey Konovalov
@ 2015-08-02 16:08 ` Peter Zijlstra
2015-08-02 20:50 ` Davidlohr Bueso
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ 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, linux-kernel,
linux-ia64, linux-metag, linux-mips, linuxppc-dev, linux-s390,
sparclinux, linux-arch, Dmitry Vyukov, Christian Borntraeger,
Davidlohr Bueso
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] 6+ messages in thread* Re: [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire
2015-08-02 15:11 [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire Andrey Konovalov
2015-08-02 16:08 ` Peter Zijlstra
@ 2015-08-02 20:50 ` Davidlohr Bueso
2015-08-03 1:41 ` Michael Ellerman
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ 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 Petkov,
linux-arm-kernel, linux-kernel, linux-ia64, linux-metag,
linux-mips, linuxppc-dev, linux-s390, sparclinux, linux-arch,
Dmitry Vyukov, Christian Borntraeger
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] 6+ messages in thread* Re: [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire
2015-08-02 15:11 [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire Andrey Konovalov
2015-08-02 16:08 ` Peter Zijlstra
2015-08-02 20:50 ` Davidlohr Bueso
@ 2015-08-03 1:41 ` Michael Ellerman
2015-08-03 6:02 ` Ralf Baechle
2015-08-03 17:00 ` [tip:locking/core] locking, arch: use WRITE_ONCE()/READ_ONCE() in smp_store_release()/smp_load_acquire() tip-bot for Andrey Konovalov
4 siblings, 0 replies; 6+ 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, linux-kernel, linux-ia64,
linux-metag, linux-mips, linuxppc-dev, linux-s390, sparclinux,
linux-arch, Dmitry Vyukov, Christian Borntraeger, Davidlohr Bueso
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] 6+ messages in thread* Re: [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire
2015-08-02 15:11 [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire Andrey Konovalov
` (2 preceding siblings ...)
2015-08-03 1:41 ` Michael Ellerman
@ 2015-08-03 6:02 ` Ralf Baechle
2015-08-03 17:00 ` [tip:locking/core] locking, arch: use WRITE_ONCE()/READ_ONCE() in smp_store_release()/smp_load_acquire() tip-bot for Andrey Konovalov
4 siblings, 0 replies; 6+ 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, linux-kernel, linux-ia64, linux-metag,
linux-mips, linuxppc-dev, linux-s390, sparclinux, linux-arch,
Dmitry Vyukov, Christian Borntraeger, Davidlohr Bueso
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] 6+ messages in thread* [tip:locking/core] locking, arch: use WRITE_ONCE()/READ_ONCE() in smp_store_release()/smp_load_acquire()
2015-08-02 15:11 [PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire Andrey Konovalov
` (3 preceding siblings ...)
2015-08-03 6:02 ` Ralf Baechle
@ 2015-08-03 17:00 ` tip-bot for Andrey Konovalov
4 siblings, 0 replies; 6+ messages in thread
From: tip-bot for Andrey Konovalov @ 2015-08-03 17:00 UTC (permalink / raw)
To: linux-tip-commits
Cc: andreyknvl, will.deacon, catalin.marinas, james.hogan, ralf, bp,
alexander.h.duyck, borntraeger, fenghua.yu, davem, mingo, dvyukov,
heiko.carstens, andre.przywara, arnd, schwidefsky, peterz, tglx,
torvalds, tony.luck, linux, linux-kernel, dave, dbueso, benh, hpa,
paulmck, paulus
Commit-ID: 76695af20c015206cffb84b15912be6797d0cca2
Gitweb: http://git.kernel.org/tip/76695af20c015206cffb84b15912be6797d0cca2
Author: Andrey Konovalov <andreyknvl@google.com>
AuthorDate: Sun, 2 Aug 2015 17:11:04 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 3 Aug 2015 10:59:30 +0200
locking, arch: use WRITE_ONCE()/READ_ONCE() in smp_store_release()/smp_load_acquire()
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 following commits:
230fa253df63 ("kernel: Provide READ_ONCE and ASSIGN_ONCE")
43239cbe79fc ("kernel: Change ASSIGN_ONCE(val, x) to WRITE_ONCE(x, val)")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Alexander Duyck <alexander.h.duyck@redhat.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arch@vger.kernel.org
Link: http://lkml.kernel.org/r/1438528264-714-1-git-send-email-andreyknvl@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
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; \
^ permalink raw reply related [flat|nested] 6+ messages in thread