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authorLinus Torvalds <torvalds@linux-foundation.org>2016-03-14 19:44:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-14 19:44:38 -0700
commite23604edac2a7be6a8808a5d13fac6b9df4eb9a8 (patch)
tree7a7fa87796fb1dc6dd355675816e2e59546d4edd /include/linux/atomic.h
parentd4e796152a049f6a675f8b6dcf7080a9d80014e5 (diff)
parent1f25184656a00a59e3a953189070d42a749f6aee (diff)
Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull NOHZ updates from Ingo Molnar: "NOHZ enhancements, by Frederic Weisbecker, which reorganizes/refactors the NOHZ 'can the tick be stopped?' infrastructure and related code to be data driven, and harmonizes the naming and handling of all the various properties" [ This makes the ugly "fetch_or()" macro that the scheduler used internally a new generic helper, and does a bad job at it. I'm pulling it, but I've asked Ingo and Frederic to get this fixed up ] * 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched-clock: Migrate to use new tick dependency mask model posix-cpu-timers: Migrate to use new tick dependency mask model sched: Migrate sched to use new tick dependency mask model sched: Account rr tasks perf: Migrate perf to use new tick dependency mask model nohz: Use enum code for tick stop failure tracing message nohz: New tick dependency mask nohz: Implement wide kick on top of irq work atomic: Export fetch_or()
Diffstat (limited to 'include/linux/atomic.h')
-rw-r--r--include/linux/atomic.h21
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