summaryrefslogtreecommitdiff
path: root/include/asm-generic/atomic.h
diff options
context:
space:
mode:
authorMark Rutland <mark.rutland@arm.com>2018-06-21 13:13:09 +0100
committerIngo Molnar <mingo@kernel.org>2018-06-21 14:22:33 +0200
commiteccc2da8c03f316bba202e15af2be4615f461900 (patch)
tree1efd0bf1e8620a33ed58cd74cacc94ffc8cf111f /include/asm-generic/atomic.h
parentbef828204a1bc7a0fd3a24551c4265e9c2ab95ed (diff)
atomics/treewide: Make atomic_fetch_add_unless() optional
Several architectures these have a near-identical implementation based on atomic_read() and atomic_cmpxchg() which we can instead define in <linux/atomic.h>, so let's do so, using something close to the existing x86 implementation with try_cmpxchg(). Where an architecture provides its own atomic_fetch_add_unless(), it must define a preprocessor symbol for it. The instrumented atomics are updated accordingly. Note that arch/arc's existing atomic_fetch_add_unless() had redundant barriers, as these are already present in its atomic_cmpxchg() implementation. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Will Deacon <will.deacon@arm.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Palmer Dabbelt <palmer@sifive.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vineet Gupta <vgupta@synopsys.com> Link: https://lore.kernel.org/lkml/20180621121321.4761-7-mark.rutland@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/asm-generic/atomic.h')
-rw-r--r--include/asm-generic/atomic.h11
1 files changed, 0 insertions, 11 deletions
diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h
index 10051ed6d088..757e45821220 100644
--- a/include/asm-generic/atomic.h
+++ b/include/asm-generic/atomic.h
@@ -221,15 +221,4 @@ static inline void atomic_dec(atomic_t *v)
#define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
-#ifndef atomic_fetch_add_unless
-static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
-{
- int c, old;
- c = atomic_read(v);
- while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c)
- c = old;
- return c;
-}
-#endif
-
#endif /* __ASM_GENERIC_ATOMIC_H */