Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 1/3] atomic: Introduce atomic_fetch_or | Date | Thu, 24 Mar 2016 15:37:59 +0100 |
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This is deemed to replace the type generic fetch_or() which brings a lot of issues such as macro induced block variable aliasing and sloppy types. Not to mention fetch_or() doesn't refer to any namespace, adding even more confusion.
So lets provide an atomic_t version. Current and next users of fetch_or are thus encouraged to use atomic_t.
Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> --- include/linux/atomic.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)
diff --git a/include/linux/atomic.h b/include/linux/atomic.h index df4f369..3d64c08 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -559,6 +559,27 @@ static inline int atomic_dec_if_positive(atomic_t *v) #endif /** + * atomic_fetch_or - perform *p |= mask and return old value of *p + * @p: pointer to atomic_t + * @mask: mask to OR on the atomic_t + */ +#ifndef atomic_fetch_or +static inline int atomic_fetch_or(atomic_t *p, int mask) +{ + int old, val = atomic_read(p); + + for (;;) { + old = atomic_cmpxchg(p, val, val | mask); + if (old == val) + break; + val = old; + } + + return old; +} +#endif + +/** * fetch_or - perform *ptr |= mask and return old value of *ptr * @ptr: pointer to value * @mask: mask to OR on the value -- 2.7.0
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