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authorVineet Gupta <Vineet.Gupta1@synopsys.com>2016-10-07 17:02:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-07 18:46:30 -0700
commit445ed0a0eac50d2a76441278a084554a4b9dcfda (patch)
treef3a8477d8dbe38e31a9297ca0d3a20b925b82bf8 /arch/ia64
parent1061b0d21e16550e7d7893a5deee2e49ea3990ad (diff)
ia64: implement atomic64_dec_if_positive
This is based on s390 version and needed to get rid of CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE Link: http://lkml.kernel.org/r/1473703083-8625-2-git-send-email-vgupta@synopsys.com Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Reported-by: kbuild test robot <fengguang.wu@intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/ia64')
-rw-r--r--arch/ia64/include/asm/atomic.h16
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/ia64/include/asm/atomic.h b/arch/ia64/include/asm/atomic.h
index f565ad376142..65d4bb2b6685 100644
--- a/arch/ia64/include/asm/atomic.h
+++ b/arch/ia64/include/asm/atomic.h
@@ -269,6 +269,22 @@ static __inline__ long atomic64_add_unless(atomic64_t *v, long a, long u)
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
+static __inline__ long atomic64_dec_if_positive(atomic64_t *v)
+{
+ long c, old, dec;
+ c = atomic64_read(v);
+ for (;;) {
+ dec = c - 1;
+ if (unlikely(dec < 0))
+ break;
+ old = atomic64_cmpxchg((v), c, dec);
+ if (likely(old == c))
+ break;
+ c = old;
+ }
+ return dec;
+}
+
/*
* Atomically add I to V and return TRUE if the resulting value is
* negative.