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| author | Peter Gonda <pgonda@google.com> | 2022-10-06 00:34:06 +0000 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2022-11-16 16:58:52 -0800 |
| commit | cf4694be2b2cf74945e50d39a02ea2307c4495f4 (patch) | |
| tree | 74389c8ce3d4978a99def91aa5f9a259a61437fb /tools/include/asm-generic | |
| parent | dc88244bf5488b04fb7bbe47d8d9c38ff8f7dbb4 (diff) | |
| download | lwn-cf4694be2b2cf74945e50d39a02ea2307c4495f4.tar.gz lwn-cf4694be2b2cf74945e50d39a02ea2307c4495f4.zip | |
tools: Add atomic_test_and_set_bit()
Add x86 and generic implementations of atomic_test_and_set_bit() to allow
KVM selftests to atomically manage bitmaps.
Note, the generic version is taken from arch_test_and_set_bit() as of
commit 415d83249709 ("locking/atomic: Make test_and_*_bit() ordered on
failure").
Signed-off-by: Peter Gonda <pgonda@google.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-5-seanjc@google.com
Diffstat (limited to 'tools/include/asm-generic')
| -rw-r--r-- | tools/include/asm-generic/atomic-gcc.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/tools/include/asm-generic/atomic-gcc.h b/tools/include/asm-generic/atomic-gcc.h index 4c1966f7c77a..6daa68bf5b9e 100644 --- a/tools/include/asm-generic/atomic-gcc.h +++ b/tools/include/asm-generic/atomic-gcc.h @@ -4,6 +4,7 @@ #include <linux/compiler.h> #include <linux/types.h> +#include <linux/bitops.h> /* * Atomic operations that C can't guarantee us. Useful for @@ -69,4 +70,15 @@ static inline int atomic_cmpxchg(atomic_t *v, int oldval, int newval) return cmpxchg(&(v)->counter, oldval, newval); } +static inline int atomic_test_and_set_bit(long nr, unsigned long *addr) +{ + unsigned long mask = BIT_MASK(nr); + long old; + + addr += BIT_WORD(nr); + + old = __sync_fetch_and_or(addr, mask); + return !!(old & mask); +} + #endif /* __TOOLS_ASM_GENERIC_ATOMIC_H */ |