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authorLinus Torvalds <torvalds@linux-foundation.org>2015-06-23 00:54:22 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-06-23 00:54:22 +0300
commit1bf7067c6e173dc10411704db48338ed69c05565 (patch)
tree06d731d9647c525fa598d03d7ec957ff9772ff40 /include/linux/compiler.h
parentfc934d40178ad4e551a17e2733241d9f29fddd70 (diff)
parent68722101ec3a0e179408a13708dd020e04f54aab (diff)
downloadlinux-1bf7067c6e173dc10411704db48338ed69c05565.tar.xz
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar: "The main changes are: - 'qspinlock' support, enabled on x86: queued spinlocks - these are now the spinlock variant used by x86 as they outperform ticket spinlocks in every category. (Waiman Long) - 'pvqspinlock' support on x86: paravirtualized variant of queued spinlocks. (Waiman Long, Peter Zijlstra) - 'qrwlock' support, enabled on x86: queued rwlocks. Similar to queued spinlocks, they are now the variant used by x86: CONFIG_ARCH_USE_QUEUED_SPINLOCKS=y CONFIG_QUEUED_SPINLOCKS=y CONFIG_ARCH_USE_QUEUED_RWLOCKS=y CONFIG_QUEUED_RWLOCKS=y - various lockdep fixlets - various locking primitives cleanups, further WRITE_ONCE() propagation" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) locking/lockdep: Remove hard coded array size dependency locking/qrwlock: Don't contend with readers when setting _QW_WAITING lockdep: Do not break user-visible string locking/arch: Rename set_mb() to smp_store_mb() locking/arch: Add WRITE_ONCE() to set_mb() rtmutex: Warn if trylock is called from hard/softirq context arch: Remove __ARCH_HAVE_CMPXCHG locking/rtmutex: Drop usage of __HAVE_ARCH_CMPXCHG locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS locking/pvqspinlock: Rename QUEUED_SPINLOCK to QUEUED_SPINLOCKS locking/pvqspinlock: Replace xchg() by the more descriptive set_mb() locking/pvqspinlock, x86: Enable PV qspinlock for Xen locking/pvqspinlock, x86: Enable PV qspinlock for KVM locking/pvqspinlock, x86: Implement the paravirt qspinlock call patching locking/pvqspinlock: Implement simple paravirt support for the qspinlock locking/qspinlock: Revert to test-and-set on hypervisors locking/qspinlock: Use a simple write to grab the lock locking/qspinlock: Optimize for smaller NR_CPUS locking/qspinlock: Extract out code snippets for the next patch locking/qspinlock: Add pending bit ...
Diffstat (limited to 'include/linux/compiler.h')
-rw-r--r--include/linux/compiler.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 5d66777914db..05be2352fef8 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -250,7 +250,7 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
({ union { typeof(x) __val; char __c[1]; } __u; __read_once_size(&(x), __u.__c, sizeof(x)); __u.__val; })
#define WRITE_ONCE(x, val) \
- ({ typeof(x) __val = (val); __write_once_size(&(x), &__val, sizeof(__val)); __val; })
+ ({ union { typeof(x) __val; char __c[1]; } __u = { .__val = (val) }; __write_once_size(&(x), __u.__c, sizeof(x)); __u.__val; })
/**
* READ_ONCE_CTRL - Read a value heading a control dependency
@@ -466,7 +466,7 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
* with an explicit memory barrier or atomic instruction that provides the
* required ordering.
*
- * If possible use READ_ONCE/ASSIGN_ONCE instead.
+ * If possible use READ_ONCE()/WRITE_ONCE() instead.
*/
#define __ACCESS_ONCE(x) ({ \
__maybe_unused typeof(x) __var = (__force typeof(x)) 0; \