diff options
author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-01-14 13:32:50 -0800 |
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committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-04-18 11:20:15 -0700 |
commit | 77e5849688670280b173bb9e0544e9da7b2acc36 (patch) | |
tree | 7d1bab5108080b74bca1c7a8d54e3be22c67c6e2 | |
parent | b8c17e6664c461e4aed545a943304c3b32dd309c (diff) | |
download | linux-77e5849688670280b173bb9e0544e9da7b2acc36.tar.bz2 |
rcu: Make arch select smp_mb__after_unlock_lock() strength
The definition of smp_mb__after_unlock_lock() is currently smp_mb()
for CONFIG_PPC and a no-op otherwise. It would be better to instead
provide an architecture-selectable Kconfig option, and select the
strength of smp_mb__after_unlock_lock() based on that option. This
commit therefore creates ARCH_WEAK_RELEASE_ACQUIRE, has PPC select it,
and bases the definition of smp_mb__after_unlock_lock() on this new
ARCH_WEAK_RELEASE_ACQUIRE Kconfig option.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Boqun Feng <boqun.feng@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: <linuxppc-dev@lists.ozlabs.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
-rw-r--r-- | arch/Kconfig | 3 | ||||
-rw-r--r-- | arch/powerpc/Kconfig | 1 | ||||
-rw-r--r-- | include/linux/rcupdate.h | 6 |
3 files changed, 7 insertions, 3 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index cd211a14a88f..adefaf344239 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -320,6 +320,9 @@ config HAVE_CMPXCHG_LOCAL config HAVE_CMPXCHG_DOUBLE bool +config ARCH_WEAK_RELEASE_ACQUIRE + bool + config ARCH_WANT_IPC_PARSE_VERSION bool diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 97a8bc8a095c..7a5c9b764cd2 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -99,6 +99,7 @@ config PPC select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF if PPC64 select ARCH_WANT_IPC_PARSE_VERSION + select ARCH_WEAK_RELEASE_ACQUIRE select BINFMT_ELF select BUILDTIME_EXTABLE_SORT select CLONE_BACKWARDS diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index de88b33c0974..e6146d0074f8 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -1127,11 +1127,11 @@ do { \ * if the UNLOCK and LOCK are executed by the same CPU or if the * UNLOCK and LOCK operate on the same lock variable. */ -#ifdef CONFIG_PPC +#ifdef CONFIG_ARCH_WEAK_RELEASE_ACQUIRE #define smp_mb__after_unlock_lock() smp_mb() /* Full ordering for lock. */ -#else /* #ifdef CONFIG_PPC */ +#else /* #ifdef CONFIG_ARCH_WEAK_RELEASE_ACQUIRE */ #define smp_mb__after_unlock_lock() do { } while (0) -#endif /* #else #ifdef CONFIG_PPC */ +#endif /* #else #ifdef CONFIG_ARCH_WEAK_RELEASE_ACQUIRE */ #endif /* __LINUX_RCUPDATE_H */ |