Commit-ID: 5acba71e18833b9d06686b3751598bfa263a3ac3 Gitweb: http://git.kernel.org/tip/5acba71e18833b9d06686b3751598bfa263a3ac3 Author: Frederic Weisbecker <[email protected]> AuthorDate: Thu, 24 Mar 2016 15:37:59 +0100 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 29 Mar 2016 11:52:11 +0200
locking/atomic: Introduce atomic_fetch_or() 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. Signed-off-by: Frederic Weisbecker <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- 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
