[PATCHv3 14/18] atomics/treewide: make atomic64_fetch_add_unless() optional

From: Mark Rutland
Date: Mon Jun 18 2018 - 06:20:08 EST


Architectures with atomic64_fetch_add_unless provide a preprocessor
symbol if they do so, and all other architectures have trivial C
implementations of atomic64_add_unless() which are near-identical.

Let's unify the trivial definitions of atomic64_fetch_add_unless() in
<linux/atomic.h>, so that we always have both
atomic64_fetch_add_unless() and atomic64_add_unless() with less
boilerplate code.

This means that atomic64_add_unless() is always implemented in core
code, and the instrumented atomics are updated accordingly.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
---
arch/arm64/include/asm/atomic.h | 12 ------------
arch/ia64/include/asm/atomic.h | 15 ---------------
arch/mips/include/asm/atomic.h | 24 ------------------------
arch/parisc/include/asm/atomic.h | 24 ------------------------
arch/s390/include/asm/atomic.h | 16 ----------------
arch/sparc/include/asm/atomic_64.h | 15 ---------------
arch/x86/include/asm/atomic64_64.h | 19 -------------------
include/asm-generic/atomic-instrumented.h | 6 ------
include/linux/atomic.h | 26 ++++++++++++++++++++++++--
9 files changed, 24 insertions(+), 133 deletions(-)

diff --git a/arch/arm64/include/asm/atomic.h b/arch/arm64/include/asm/atomic.h
index 22c8c43d6689..82db0e4febd4 100644
--- a/arch/arm64/include/asm/atomic.h
+++ b/arch/arm64/include/asm/atomic.h
@@ -40,17 +40,6 @@

#include <asm/cmpxchg.h>

-#define ___atomic_add_unless(v, a, u, sfx) \
-({ \
- typeof((v)->counter) c, old; \
- \
- c = atomic##sfx##_read(v); \
- while (c != (u) && \
- (old = atomic##sfx##_cmpxchg((v), c, c + (a))) != c) \
- c = old; \
- c; \
- })
-
#define ATOMIC_INIT(i) { (i) }

#define atomic_read(v) READ_ONCE((v)->counter)
@@ -200,7 +189,6 @@
#define atomic64_dec_and_test(v) (atomic64_dec_return(v) == 0)
#define atomic64_sub_and_test(i, v) (atomic64_sub_return((i), (v)) == 0)
#define atomic64_add_negative(i, v) (atomic64_add_return((i), (v)) < 0)
-#define atomic64_add_unless(v, a, u) (___atomic_add_unless(v, a, u, 64) != u)
#define atomic64_andnot atomic64_andnot

#endif
diff --git a/arch/ia64/include/asm/atomic.h b/arch/ia64/include/asm/atomic.h
index cfe44086338e..0f80a3eafaba 100644
--- a/arch/ia64/include/asm/atomic.h
+++ b/arch/ia64/include/asm/atomic.h
@@ -215,21 +215,6 @@ ATOMIC64_FETCH_OP(xor, ^)
(cmpxchg(&((v)->counter), old, new))
#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))

-static __inline__ long atomic64_add_unless(atomic64_t *v, long a, long u)
-{
- long c, old;
- c = atomic64_read(v);
- for (;;) {
- if (unlikely(c == (u)))
- break;
- old = atomic64_cmpxchg((v), c, c + (a));
- if (likely(old == c))
- break;
- c = old;
- }
- return c != (u);
-}
-
static __inline__ long atomic64_dec_if_positive(atomic64_t *v)
{
long c, old, dec;
diff --git a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h
index 794734e730d9..d42b27df1548 100644
--- a/arch/mips/include/asm/atomic.h
+++ b/arch/mips/include/asm/atomic.h
@@ -596,30 +596,6 @@ static __inline__ long atomic64_sub_if_positive(long i, atomic64_t * v)
((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
#define atomic64_xchg(v, new) (xchg(&((v)->counter), (new)))

-/**
- * atomic64_add_unless - add unless the number is a given value
- * @v: pointer of type atomic64_t
- * @a: the amount to add to v...
- * @u: ...unless v is equal to u.
- *
- * Atomically adds @a to @v, so long as it was not @u.
- * Returns true iff @v was not @u.
- */
-static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
-{
- long c, old;
- c = atomic64_read(v);
- for (;;) {
- if (unlikely(c == (u)))
- break;
- old = atomic64_cmpxchg((v), c, c + (a));
- if (likely(old == c))
- break;
- c = old;
- }
- return c != (u);
-}
-
#define atomic64_dec_return(v) atomic64_sub_return(1, (v))
#define atomic64_inc_return(v) atomic64_add_return(1, (v))

diff --git a/arch/parisc/include/asm/atomic.h b/arch/parisc/include/asm/atomic.h
index b2b6261d05e7..f53ba2d6ff67 100644
--- a/arch/parisc/include/asm/atomic.h
+++ b/arch/parisc/include/asm/atomic.h
@@ -257,30 +257,6 @@ atomic64_read(const atomic64_t *v)
((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))

-/**
- * atomic64_add_unless - add unless the number is a given value
- * @v: pointer of type atomic64_t
- * @a: the amount to add to v...
- * @u: ...unless v is equal to u.
- *
- * Atomically adds @a to @v, so long as it was not @u.
- * Returns the old value of @v.
- */
-static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
-{
- long c, old;
- c = atomic64_read(v);
- for (;;) {
- if (unlikely(c == (u)))
- break;
- old = atomic64_cmpxchg((v), c, c + (a));
- if (likely(old == c))
- break;
- c = old;
- }
- return c != (u);
-}
-
/*
* atomic64_dec_if_positive - decrement by 1 if old value positive
* @v: pointer of type atomic_t
diff --git a/arch/s390/include/asm/atomic.h b/arch/s390/include/asm/atomic.h
index 26c6b713a7a3..eb9329741bad 100644
--- a/arch/s390/include/asm/atomic.h
+++ b/arch/s390/include/asm/atomic.h
@@ -153,22 +153,6 @@ ATOMIC64_OPS(xor)

#undef ATOMIC64_OPS

-static inline int atomic64_add_unless(atomic64_t *v, long i, long u)
-{
- long c, old;
-
- c = atomic64_read(v);
- for (;;) {
- if (unlikely(c == u))
- break;
- old = atomic64_cmpxchg(v, c, c + i);
- if (likely(old == c))
- break;
- c = old;
- }
- return c != u;
-}
-
static inline long atomic64_dec_if_positive(atomic64_t *v)
{
long c, old, dec;
diff --git a/arch/sparc/include/asm/atomic_64.h b/arch/sparc/include/asm/atomic_64.h
index e4f1c93db31f..458783e99997 100644
--- a/arch/sparc/include/asm/atomic_64.h
+++ b/arch/sparc/include/asm/atomic_64.h
@@ -93,21 +93,6 @@ static inline int atomic_xchg(atomic_t *v, int new)
((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))

-static inline long atomic64_add_unless(atomic64_t *v, long a, long u)
-{
- long c, old;
- c = atomic64_read(v);
- for (;;) {
- if (unlikely(c == (u)))
- break;
- old = atomic64_cmpxchg((v), c, c + (a));
- if (likely(old == c))
- break;
- c = old;
- }
- return c != (u);
-}
-
long atomic64_dec_if_positive(atomic64_t *v);

#endif /* !(__ARCH_SPARC64_ATOMIC__) */
diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h
index 6f95023894b7..7e04b294e6eb 100644
--- a/arch/x86/include/asm/atomic64_64.h
+++ b/arch/x86/include/asm/atomic64_64.h
@@ -188,25 +188,6 @@ static inline long arch_atomic64_xchg(atomic64_t *v, long new)
return xchg(&v->counter, new);
}

-/**
- * arch_atomic64_add_unless - add unless the number is a given value
- * @v: pointer of type atomic64_t
- * @a: the amount to add to v...
- * @u: ...unless v is equal to u.
- *
- * Atomically adds @a to @v, so long as it was not @u.
- * Returns the old value of @v.
- */
-static inline bool arch_atomic64_add_unless(atomic64_t *v, long a, long u)
-{
- s64 c = arch_atomic64_read(v);
- do {
- if (unlikely(c == u))
- return false;
- } while (!arch_atomic64_try_cmpxchg(v, &c, c + a));
- return true;
-}
-
/*
* arch_atomic64_dec_if_positive - decrement by 1 if old value positive
* @v: pointer of type atomic_t
diff --git a/include/asm-generic/atomic-instrumented.h b/include/asm-generic/atomic-instrumented.h
index ab011e1a02fc..23cd696c2778 100644
--- a/include/asm-generic/atomic-instrumented.h
+++ b/include/asm-generic/atomic-instrumented.h
@@ -100,12 +100,6 @@ static __always_inline int atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u
kasan_check_write(v, sizeof(*v));
return arch_atomic64_fetch_add_unless(v, a, u);
}
-#else
-static __always_inline bool atomic64_add_unless(atomic64_t *v, s64 a, s64 u)
-{
- kasan_check_write(v, sizeof(*v));
- return arch_atomic64_add_unless(v, a, u);
-}
#endif

static __always_inline void atomic_inc(atomic_t *v)
diff --git a/include/linux/atomic.h b/include/linux/atomic.h
index 3c03de648007..530562ac7909 100644
--- a/include/linux/atomic.h
+++ b/include/linux/atomic.h
@@ -1043,6 +1043,30 @@ static inline int atomic_dec_if_positive(atomic_t *v)
#endif /* atomic64_try_cmpxchg */

/**
+ * atomic64_fetch_add_unless - add unless the number is already a given value
+ * @v: pointer of type atomic64_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
+ *
+ * Atomically adds @a to @v, if @v was not already @u.
+ * Returns the original value of @v.
+ */
+#ifndef atomic64_fetch_add_unless
+static inline long long atomic64_fetch_add_unless(atomic64_t *v, long long a,
+ long long u)
+{
+ long long c = atomic64_read(v);
+
+ do {
+ if (unlikely(c == u))
+ break;
+ } while (!atomic64_try_cmpxchg(v, &c, c + a));
+
+ return c;
+}
+#endif
+
+/**
* atomic64_add_unless - add unless the number is already a given value
* @v: pointer of type atomic_t
* @a: the amount to add to v...
@@ -1051,12 +1075,10 @@ static inline int atomic_dec_if_positive(atomic_t *v)
* Atomically adds @a to @v, if @v was not already @u.
* Returns true if the addition was done.
*/
-#ifdef atomic64_fetch_add_unless
static inline bool atomic64_add_unless(atomic64_t *v, long long a, long long u)
{
return atomic64_fetch_add_unless(v, a, u) != u;
}
-#endif

/**
* atomic64_inc_not_zero - increment unless the number is zero
--
2.11.0