[PATCHv2] atomic: add *_dec_not_zero

From: Sven Eckelmann
Date: Wed May 18 2011 - 15:50:14 EST

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Introduce an *_dec_not_zero operation. Make this a special case of
*_add_unless because batman-adv uses atomic_dec_not_zero in different
places like re-broadcast queue or aggregation queue management. There
are other non-final patches which may also want to use this macro.

Reported-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sven Eckelmann <sven@xxxxxxxxxxxxx>
Acked-by: Mike Frysinger <vapier@xxxxxxxxxx>
Acked-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Acked-by: David S. Miller <davem@xxxxxxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxx>
Acked-by: Jesper Nilsson <jesper.nilsson@xxxxxxxx>
Acked-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Acked-by: David Howells <dhowells@xxxxxxxxxx>
Acked-by: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Acked-by: Matt Turner <mattst88@xxxxxxxxx>
Acked-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: linux-ia64@xxxxxxxxxxxxxxx
Cc: Hirokazu Takata <takata@xxxxxxxxxxxxxx>
Cc: linux-m32r@xxxxxxxxxxxxxxxxx
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: linux390@xxxxxxxxxx
Cc: linux-s390@xxxxxxxxxxxxxxx
Cc: Paul Mundt <lethal@xxxxxxxxxxxx>
Cc: linux-sh@xxxxxxxxxxxxxxx
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
---
This is actually the same patch as before, but I am still waiting for
some (N)Acks for ia64, m32r, s390, sh and generic.

arch/alpha/include/asm/atomic.h | 2 ++
arch/alpha/include/asm/local.h | 1 +
arch/arm/include/asm/atomic.h | 2 ++
arch/avr32/include/asm/atomic.h | 1 +
arch/blackfin/include/asm/atomic.h | 1 +
arch/cris/include/asm/atomic.h | 1 +
arch/frv/include/asm/atomic.h | 1 +
arch/h8300/include/asm/atomic.h | 1 +
arch/ia64/include/asm/atomic.h | 2 ++
arch/m32r/include/asm/atomic.h | 1 +
arch/m32r/include/asm/local.h | 1 +
arch/m68k/include/asm/atomic.h | 1 +
arch/mips/include/asm/atomic.h | 2 ++
arch/mips/include/asm/local.h | 1 +
arch/mn10300/include/asm/atomic.h | 1 +
arch/parisc/include/asm/atomic.h | 2 ++
arch/powerpc/include/asm/atomic.h | 2 ++
arch/powerpc/include/asm/local.h | 1 +
arch/s390/include/asm/atomic.h | 2 ++
arch/sh/include/asm/atomic.h | 1 +
arch/sparc/include/asm/atomic_32.h | 1 +
arch/sparc/include/asm/atomic_64.h | 2 ++
arch/tile/include/asm/atomic.h | 9 +++++++++
arch/tile/include/asm/atomic_32.h | 1 +
arch/x86/include/asm/atomic.h | 1 +
arch/x86/include/asm/atomic64_64.h | 1 +
arch/xtensa/include/asm/atomic.h | 1 +
include/asm-generic/atomic-long.h | 2 ++
include/asm-generic/atomic.h | 1 +
include/asm-generic/atomic64.h | 1 +
include/asm-generic/local.h | 1 +
include/asm-generic/local64.h | 2 ++
32 files changed, 50 insertions(+), 0 deletions(-)

diff --git a/arch/alpha/include/asm/atomic.h b/arch/alpha/include/asm/atomic.h
index e756d04..7e9434e 100644
--- a/arch/alpha/include/asm/atomic.h
+++ b/arch/alpha/include/asm/atomic.h
@@ -200,6 +200,7 @@ static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

/**
* atomic64_add_unless - add unless the number is a given value
@@ -226,6 +227,7 @@ static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
}

#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
+#define atomic64_dec_not_zero(v) atomic64_add_unless((v), -1, 0)

#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
#define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)
diff --git a/arch/alpha/include/asm/local.h b/arch/alpha/include/asm/local.h
index b9e3e33..09fb327 100644
--- a/arch/alpha/include/asm/local.h
+++ b/arch/alpha/include/asm/local.h
@@ -79,6 +79,7 @@ static __inline__ long local_sub_return(long i, local_t * l)
c != (u); \
})
#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
+#define local_dec_not_zero(l) local_add_unless((l), -1, 0)

#define local_add_negative(a, l) (local_add_return((a), (l)) < 0)

diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
index 7e79503..a005265 100644
--- a/arch/arm/include/asm/atomic.h
+++ b/arch/arm/include/asm/atomic.h
@@ -218,6 +218,7 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
return c != u;
}
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

#define atomic_inc(v) atomic_add(1, v)
#define atomic_dec(v) atomic_sub(1, v)
@@ -459,6 +460,7 @@ static inline int atomic64_add_unless(atomic64_t *v, u64 a, u64 u)
#define atomic64_dec_return(v) atomic64_sub_return(1LL, (v))
#define atomic64_dec_and_test(v) (atomic64_dec_return((v)) == 0)
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1LL, 0LL)
+#define atomic64_dec_not_zero(v) atomic64_add_unless((v), -1LL, 0LL)

#else /* !CONFIG_GENERIC_ATOMIC64 */
#include <asm-generic/atomic64.h>
diff --git a/arch/avr32/include/asm/atomic.h b/arch/avr32/include/asm/atomic.h
index bbce6a1..e6f39c1 100644
--- a/arch/avr32/include/asm/atomic.h
+++ b/arch/avr32/include/asm/atomic.h
@@ -189,6 +189,7 @@ static inline int atomic_sub_if_positive(int i, atomic_t *v)
#define atomic_add_negative(i, v) (atomic_add_return(i, v) < 0)

#define atomic_inc_not_zero(v) atomic_add_unless(v, 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
#define atomic_dec_if_positive(v) atomic_sub_if_positive(1, v)

#define smp_mb__before_atomic_dec() barrier()
diff --git a/arch/blackfin/include/asm/atomic.h b/arch/blackfin/include/asm/atomic.h
index e485089..900682e 100644
--- a/arch/blackfin/include/asm/atomic.h
+++ b/arch/blackfin/include/asm/atomic.h
@@ -103,6 +103,7 @@ static inline int atomic_test_mask(int mask, atomic_t *v)
c != (u); \
})
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

/*
* atomic_inc_and_test - increment and test
diff --git a/arch/cris/include/asm/atomic.h b/arch/cris/include/asm/atomic.h
index 88dc9b9..9db2767 100644
--- a/arch/cris/include/asm/atomic.h
+++ b/arch/cris/include/asm/atomic.h
@@ -151,6 +151,7 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
return ret != u;
}
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

/* Atomic operations are already serializing */
#define smp_mb__before_atomic_dec() barrier()
diff --git a/arch/frv/include/asm/atomic.h b/arch/frv/include/asm/atomic.h
index fae32c7..90f12a8 100644
--- a/arch/frv/include/asm/atomic.h
+++ b/arch/frv/include/asm/atomic.h
@@ -257,6 +257,7 @@ static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

#include <asm-generic/atomic-long.h>
#endif /* _ASM_ATOMIC_H */
diff --git a/arch/h8300/include/asm/atomic.h b/arch/h8300/include/asm/atomic.h
index 984221a..eda4c8a 100644
--- a/arch/h8300/include/asm/atomic.h
+++ b/arch/h8300/include/asm/atomic.h
@@ -117,6 +117,7 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
return ret != u;
}
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

static __inline__ void atomic_clear_mask(unsigned long mask, unsigned long *v)
{
diff --git a/arch/ia64/include/asm/atomic.h b/arch/ia64/include/asm/atomic.h
index 4468814..e2777a9 100644
--- a/arch/ia64/include/asm/atomic.h
+++ b/arch/ia64/include/asm/atomic.h
@@ -106,6 +106,7 @@ static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

static __inline__ long atomic64_add_unless(atomic64_t *v, long a, long u)
{
@@ -123,6 +124,7 @@ 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)
+#define atomic64_dec_not_zero(v) atomic64_add_unless((v), -1, 0)

#define atomic_add_return(i,v) \
({ \
diff --git a/arch/m32r/include/asm/atomic.h b/arch/m32r/include/asm/atomic.h
index d44a51e..4e0b4ec 100644
--- a/arch/m32r/include/asm/atomic.h
+++ b/arch/m32r/include/asm/atomic.h
@@ -263,6 +263,7 @@ static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

static __inline__ void atomic_clear_mask(unsigned long mask, atomic_t *addr)
{
diff --git a/arch/m32r/include/asm/local.h b/arch/m32r/include/asm/local.h
index 734bca8..d536082 100644
--- a/arch/m32r/include/asm/local.h
+++ b/arch/m32r/include/asm/local.h
@@ -272,6 +272,7 @@ static inline int local_add_unless(local_t *l, long a, long u)
}

#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
+#define local_dec_not_zero(l) local_add_unless((l), -1, 0)

static inline void local_clear_mask(unsigned long mask, local_t *addr)
{
diff --git a/arch/m68k/include/asm/atomic.h b/arch/m68k/include/asm/atomic.h
index 03ae3d1..187a33f 100644
--- a/arch/m68k/include/asm/atomic.h
+++ b/arch/m68k/include/asm/atomic.h
@@ -199,6 +199,7 @@ static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

/* Atomic operations are already serializing */
#define smp_mb__before_atomic_dec() barrier()
diff --git a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h
index 4a02fe8..8c4109e 100644
--- a/arch/mips/include/asm/atomic.h
+++ b/arch/mips/include/asm/atomic.h
@@ -326,6 +326,7 @@ static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
return c != (u);
}
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

#define atomic_dec_return(v) atomic_sub_return(1, (v))
#define atomic_inc_return(v) atomic_add_return(1, (v))
@@ -698,6 +699,7 @@ static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
}

#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
+#define atomic64_dec_not_zero(v) atomic64_add_unless((v), -1, 0)

#define atomic64_dec_return(v) atomic64_sub_return(1, (v))
#define atomic64_inc_return(v) atomic64_add_return(1, (v))
diff --git a/arch/mips/include/asm/local.h b/arch/mips/include/asm/local.h
index fffc830..c34d3ca 100644
--- a/arch/mips/include/asm/local.h
+++ b/arch/mips/include/asm/local.h
@@ -137,6 +137,7 @@ static __inline__ long local_sub_return(long i, local_t * l)
c != (u); \
})
#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
+#define local_dec_not_zero(l) local_add_unless((l), -1, 0)

#define local_dec_return(l) local_sub_return(1, (l))
#define local_inc_return(l) local_add_return(1, (l))
diff --git a/arch/mn10300/include/asm/atomic.h b/arch/mn10300/include/asm/atomic.h
index 9d773a6..bcad5d1 100644
--- a/arch/mn10300/include/asm/atomic.h
+++ b/arch/mn10300/include/asm/atomic.h
@@ -270,6 +270,7 @@ static inline void atomic_dec(atomic_t *v)
})

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

/**
* atomic_clear_mask - Atomically clear bits in memory
diff --git a/arch/parisc/include/asm/atomic.h b/arch/parisc/include/asm/atomic.h
index f819559..c2353cf 100644
--- a/arch/parisc/include/asm/atomic.h
+++ b/arch/parisc/include/asm/atomic.h
@@ -221,6 +221,7 @@ static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

#define atomic_add(i,v) ((void)(__atomic_add_return( (i),(v))))
#define atomic_sub(i,v) ((void)(__atomic_add_return(-(i),(v))))
@@ -335,6 +336,7 @@ static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
}

#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
+#define atomic64_dec_not_zero(v) atomic64_add_unless((v), -1, 0)

#else /* CONFIG_64BIT */

diff --git a/arch/powerpc/include/asm/atomic.h b/arch/powerpc/include/asm/atomic.h
index b8f152e..906f49a 100644
--- a/arch/powerpc/include/asm/atomic.h
+++ b/arch/powerpc/include/asm/atomic.h
@@ -213,6 +213,7 @@ static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

#define atomic_sub_and_test(a, v) (atomic_sub_return((a), (v)) == 0)
#define atomic_dec_and_test(v) (atomic_dec_return((v)) == 0)
@@ -469,6 +470,7 @@ static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
}

#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
+#define atomic64_dec_not_zero(v) atomic64_add_unless((v), -1, 0)

#else /* __powerpc64__ */
#include <asm-generic/atomic64.h>
diff --git a/arch/powerpc/include/asm/local.h b/arch/powerpc/include/asm/local.h
index c2410af..3d4c58a 100644
--- a/arch/powerpc/include/asm/local.h
+++ b/arch/powerpc/include/asm/local.h
@@ -134,6 +134,7 @@ static __inline__ int local_add_unless(local_t *l, long a, long u)
}

#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
+#define local_dec_not_zero(l) local_add_unless((l), -1, 0)

#define local_sub_and_test(a, l) (local_sub_return((a), (l)) == 0)
#define local_dec_and_test(l) (local_dec_return((l)) == 0)
diff --git a/arch/s390/include/asm/atomic.h b/arch/s390/include/asm/atomic.h
index d9db138..09972c3 100644
--- a/arch/s390/include/asm/atomic.h
+++ b/arch/s390/include/asm/atomic.h
@@ -109,6 +109,7 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

#undef __CS_LOOP

@@ -326,6 +327,7 @@ static inline long long atomic64_dec_if_positive(atomic64_t *v)
#define atomic64_dec_return(_v) atomic64_sub_return(1, _v)
#define atomic64_dec_and_test(_v) (atomic64_sub_return(1, _v) == 0)
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
+#define atomic64_dec_not_zero(v) atomic64_add_unless((v), -1, 0)

#define smp_mb__before_atomic_dec() smp_mb()
#define smp_mb__after_atomic_dec() smp_mb()
diff --git a/arch/sh/include/asm/atomic.h b/arch/sh/include/asm/atomic.h
index c798312..848849e 100644
--- a/arch/sh/include/asm/atomic.h
+++ b/arch/sh/include/asm/atomic.h
@@ -31,6 +31,7 @@
#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

#define atomic_inc(v) atomic_add(1, (v))
#define atomic_dec(v) atomic_sub(1, (v))
diff --git a/arch/sparc/include/asm/atomic_32.h b/arch/sparc/include/asm/atomic_32.h
index 7ae128b..c7da1e5 100644
--- a/arch/sparc/include/asm/atomic_32.h
+++ b/arch/sparc/include/asm/atomic_32.h
@@ -53,6 +53,7 @@ extern void atomic_set(atomic_t *, int);
#define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0)

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

/* This is the old 24-bit implementation. It's still used internally
* by some sparc-specific code, notably the semaphore implementation.
diff --git a/arch/sparc/include/asm/atomic_64.h b/arch/sparc/include/asm/atomic_64.h
index bdb2ff8..23ad7cf 100644
--- a/arch/sparc/include/asm/atomic_64.h
+++ b/arch/sparc/include/asm/atomic_64.h
@@ -86,6 +86,7 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

#define atomic64_cmpxchg(v, o, n) \
((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
@@ -107,6 +108,7 @@ 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)
+#define atomic64_dec_not_zero(v) atomic64_add_unless((v), -1, 0)

/* Atomic operations are already serializing */
#define smp_mb__before_atomic_dec() barrier()
diff --git a/arch/tile/include/asm/atomic.h b/arch/tile/include/asm/atomic.h
index 75a1602..7fd7be2 100644
--- a/arch/tile/include/asm/atomic.h
+++ b/arch/tile/include/asm/atomic.h
@@ -130,6 +130,15 @@ static inline int atomic_read(const atomic_t *v)
*/
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)

+/**
+ * atomic_dec_not_zero - decrement unless the number is zero
+ * @v: pointer of type atomic_t
+ *
+ * Atomically decrement @v by 1, so long as @v is non-zero.
+ * Returns non-zero if @v was non-zero, and zero otherwise.
+ */
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
+

/*
* We define xchg() and cmpxchg() in the included headers.
diff --git a/arch/tile/include/asm/atomic_32.h b/arch/tile/include/asm/atomic_32.h
index ed359aee..43137bd 100644
--- a/arch/tile/include/asm/atomic_32.h
+++ b/arch/tile/include/asm/atomic_32.h
@@ -243,6 +243,7 @@ static inline void atomic64_set(atomic64_t *v, u64 n)
#define atomic64_dec_return(v) atomic64_sub_return(1LL, (v))
#define atomic64_dec_and_test(v) (atomic64_dec_return((v)) == 0)
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1LL, 0LL)
+#define atomic64_dec_not_zero(v) atomic64_add_unless((v), -1LL, 0LL)

/*
* We need to barrier before modifying the word, since the _atomic_xxx()
diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h
index 952a826..7102a0b 100644
--- a/arch/x86/include/asm/atomic.h
+++ b/arch/x86/include/asm/atomic.h
@@ -245,6 +245,7 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

/*
* atomic_dec_if_positive - decrement by 1 if old value positive
diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h
index 49fd1ea..2cb37f4 100644
--- a/arch/x86/include/asm/atomic64_64.h
+++ b/arch/x86/include/asm/atomic64_64.h
@@ -220,6 +220,7 @@ static inline int atomic64_add_unless(atomic64_t *v, long a, long u)
}

#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
+#define atomic64_dec_not_zero(v) atomic64_add_unless((v), -1, 0)

/*
* atomic64_dec_if_positive - decrement by 1 if old value positive
diff --git a/arch/xtensa/include/asm/atomic.h b/arch/xtensa/include/asm/atomic.h
index a96a061..3b2a7b3 100644
--- a/arch/xtensa/include/asm/atomic.h
+++ b/arch/xtensa/include/asm/atomic.h
@@ -249,6 +249,7 @@ static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
{
diff --git a/include/asm-generic/atomic-long.h b/include/asm-generic/atomic-long.h
index b7babf0..0fe75ab 100644
--- a/include/asm-generic/atomic-long.h
+++ b/include/asm-generic/atomic-long.h
@@ -130,6 +130,7 @@ static inline long atomic_long_add_unless(atomic_long_t *l, long a, long u)
}

#define atomic_long_inc_not_zero(l) atomic64_inc_not_zero((atomic64_t *)(l))
+#define atomic_long_dec_not_zero(l) atomic64_dec_not_zero((atomic64_t *)(l))

#define atomic_long_cmpxchg(l, old, new) \
(atomic64_cmpxchg((atomic64_t *)(l), (old), (new)))
@@ -247,6 +248,7 @@ static inline long atomic_long_add_unless(atomic_long_t *l, long a, long u)
}

#define atomic_long_inc_not_zero(l) atomic_inc_not_zero((atomic_t *)(l))
+#define atomic_long_dec_not_zero(l) atomic_dec_not_zero((atomic_t *)(l))

#define atomic_long_cmpxchg(l, old, new) \
(atomic_cmpxchg((atomic_t *)(l), (old), (new)))
diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h
index e994197..4e1d3ef 100644
--- a/include/asm-generic/atomic.h
+++ b/include/asm-generic/atomic.h
@@ -139,6 +139,7 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)

static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
{
diff --git a/include/asm-generic/atomic64.h b/include/asm-generic/atomic64.h
index b18ce4f..90ff9b1 100644
--- a/include/asm-generic/atomic64.h
+++ b/include/asm-generic/atomic64.h
@@ -38,5 +38,6 @@ extern int atomic64_add_unless(atomic64_t *v, long long a, long long u);
#define atomic64_dec_return(v) atomic64_sub_return(1LL, (v))
#define atomic64_dec_and_test(v) (atomic64_dec_return((v)) == 0)
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1LL, 0LL)
+#define atomic64_dec_not_zero(v) atomic64_add_unless((v), -1LL, 0LL)

#endif /* _ASM_GENERIC_ATOMIC64_H */
diff --git a/include/asm-generic/local.h b/include/asm-generic/local.h
index c8a5d68..82ef01f 100644
--- a/include/asm-generic/local.h
+++ b/include/asm-generic/local.h
@@ -44,6 +44,7 @@ typedef struct
#define local_xchg(l, n) atomic_long_xchg((&(l)->a), (n))
#define local_add_unless(l, _a, u) atomic_long_add_unless((&(l)->a), (_a), (u))
#define local_inc_not_zero(l) atomic_long_inc_not_zero(&(l)->a)
+#define local_dec_not_zero(l) atomic_long_dec_not_zero(&(l)->a)

/* Non-atomic variants, ie. preemption disabled and won't be touched
* in interrupt, etc. Some archs can optimize this case well. */
diff --git a/include/asm-generic/local64.h b/include/asm-generic/local64.h
index 02ac760..aa3a841 100644
--- a/include/asm-generic/local64.h
+++ b/include/asm-generic/local64.h
@@ -45,6 +45,7 @@ typedef struct {
#define local64_xchg(l, n) local_xchg((&(l)->a), (n))
#define local64_add_unless(l, _a, u) local_add_unless((&(l)->a), (_a), (u))
#define local64_inc_not_zero(l) local_inc_not_zero(&(l)->a)
+#define local64_dec_not_zero(l) local_dec_not_zero(&(l)->a)

/* Non-atomic variants, ie. preemption disabled and won't be touched
* in interrupt, etc. Some archs can optimize this case well. */
@@ -83,6 +84,7 @@ typedef struct {
#define local64_xchg(l, n) atomic64_xchg((&(l)->a), (n))
#define local64_add_unless(l, _a, u) atomic64_add_unless((&(l)->a), (_a), (u))
#define local64_inc_not_zero(l) atomic64_inc_not_zero(&(l)->a)
+#define local64_dec_not_zero(l) atomic64_dec_not_zero(&(l)->a)

/* Non-atomic variants, ie. preemption disabled and won't be touched
* in interrupt, etc. Some archs can optimize this case well. */
--
1.7.5.1

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