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| author | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2012-09-03 09:26:33 +0300 |
|---|---|---|
| committer | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2012-09-03 09:26:33 +0300 |
| commit | c50e86ce7c2961a41f2f7aa6e4fd6c99229ba205 (patch) | |
| tree | 4ea36009719bd8fc523239fe1bdccb90f0dce3ae /arch/x86/include/asm/bitops.h | |
| parent | 14d33d384693eb6083396199de516fdef320f7af (diff) | |
| parent | 4cbe5a555fa58a79b6ecbb6c531b8bab0650778d (diff) | |
Merge tag 'v3.6-rc4'
Merge 3.6-rc4 to get latest OMAP and device tree fixes.
Diffstat (limited to 'arch/x86/include/asm/bitops.h')
| -rw-r--r-- | arch/x86/include/asm/bitops.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h index a6983b27722..72f5009deb5 100644 --- a/arch/x86/include/asm/bitops.h +++ b/arch/x86/include/asm/bitops.h @@ -264,6 +264,13 @@ static inline int test_and_clear_bit(int nr, volatile unsigned long *addr) * This operation is non-atomic and can be reordered. * If two examples of this operation race, one can appear to succeed * but actually fail. You must protect multiple accesses with a lock. + * + * Note: the operation is performed atomically with respect to + * the local CPU, but not other CPUs. Portable code should not + * rely on this behaviour. + * KVM relies on this behaviour on x86 for modifying memory that is also + * accessed from a hypervisor on the same CPU if running in a VM: don't change + * this without also updating arch/x86/kernel/kvm.c */ static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr) { |