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| author | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2012-08-13 15:39:10 -0400 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2012-08-13 15:39:10 -0400 |
| commit | 0980bd9cd32de2fef7eaa2858345c49d14498625 (patch) | |
| tree | 41f5f823d0569a81b22037e79c22d823933a63f1 /arch/x86/include/asm/bitops.h | |
| parent | 78821b2c0299ab807d483802f09897728b93bce0 (diff) | |
| parent | 0d7614f09c1ebdbaa1599a5aba7593f147bf96ee (diff) | |
Merge commit 'v3.6-rc1' into linux-next
* commit 'v3.6-rc1': (9532 commits)
Linux 3.6-rc1
mm: remove node_start_pfn checking in new WARN_ON for now
ARM: mmp: add missing irqs.h
arm: mvebu: fix typo in .dtsi comment for Armada XP SoCs
ARM: PRIMA2: delete redundant codes to restore LATCHED when timer resumes
libceph: fix crypto key null deref, memory leak
ceph: simplify+fix atomic_open
sh: explicitly include sh_dma.h in setup-sh7722.c
um: Add arch/x86/um to MAINTAINERS
um: pass siginfo to guest process
um: fix ubd_file_size for read-only files
md/dm-raid: DM_RAID should select MD_RAID10
md/raid1: submit IO from originating thread instead of md thread.
raid5: raid5d handle stripe in batch way
raid5: make_request use batch stripe release
um: pull interrupt_end() into userspace()
um: split syscall_trace(), pass pt_regs to it
um: switch UPT_SET_RETURN_VALUE and regs_return_value to pt_regs
MIPS: Loongson 2: Sort out clock managment.
locks: remove unused lm_release_private
...
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 a6983b277220..72f5009deb5a 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) { |