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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2015-08-11 18:03:23 +0200 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2016-02-13 15:34:28 +0100 |
| commit | 5fd7a09cfb8c6852f596c1f8c891c6158395250e (patch) | |
| tree | c136e50a60a4328e7779d01c3972d477883dc39f /include | |
| parent | Linux 4.5-rc2 (diff) | |
| download | linux-5fd7a09cfb8c6852f596c1f8c891c6158395250e.tar.xz linux-5fd7a09cfb8c6852f596c1f8c891c6158395250e.zip | |
atomic: Export fetch_or()
Export fetch_or() that's implemented and used internally by the
scheduler. We are going to use it for NO_HZ so make it generally
available.
Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/atomic.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/include/linux/atomic.h b/include/linux/atomic.h index 301de78d65f7..6c502cb13c95 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -548,6 +548,27 @@ static inline int atomic_dec_if_positive(atomic_t *v) } #endif +/** + * fetch_or - perform *ptr |= mask and return old value of *ptr + * @ptr: pointer to value + * @mask: mask to OR on the value + * + * cmpxchg based fetch_or, macro so it works for different integer types + */ +#ifndef fetch_or +#define fetch_or(ptr, mask) \ +({ typeof(*(ptr)) __old, __val = *(ptr); \ + for (;;) { \ + __old = cmpxchg((ptr), __val, __val | (mask)); \ + if (__old == __val) \ + break; \ + __val = __old; \ + } \ + __old; \ +}) +#endif + + #ifdef CONFIG_GENERIC_ATOMIC64 #include <asm-generic/atomic64.h> #endif |