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atomics/treewide: Make conditional inc/dec ops optional 

The conditional inc/dec ops differ for atomic_t and atomic64_t:

- atomic_inc_unless_positive() is optional for atomic_t, and doesn't exist for atomic64_t.
- atomic_dec_unless_negative() is optional for atomic_t, and doesn't exist for atomic64_t.
- atomic_dec_if_positive is optional for atomic_t, and is mandatory for atomic64_t.

Let's make these consistently optional for both. At the same time, let's
clean up the existing fallbacks to use atomic_try_cmpxchg().

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@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20180621121321.4761-18-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Mark Rutland 2018-06-21 13:13:20 +01:00 committed by Ingo Molnar
parent 9837559d8e
commit b3a2a05f91
14 changed files with 85 additions and 98 deletions
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1
arch/alpha/include/asm/atomic.h
View File

@ -296,5 +296,6 @@ static inline long atomic64_dec_if_positive(atomic64_t *v)
smp_mb();
return old - 1;
}
#define atomic64_dec_if_positive atomic64_dec_if_positive
#endif /* _ALPHA_ATOMIC_H */

1
arch/arc/include/asm/atomic.h
View File

@ -517,6 +517,7 @@ static inline long long atomic64_dec_if_positive(atomic64_t *v)
return val;
}
#define atomic64_dec_if_positive atomic64_dec_if_positive
/**
* atomic64_fetch_add_unless - add unless the number is a given value

1
arch/arm/include/asm/atomic.h
View File

@ -474,6 +474,7 @@ static inline long long atomic64_dec_if_positive(atomic64_t *v)
return result;
}
#define atomic64_dec_if_positive atomic64_dec_if_positive
static inline long long atomic64_fetch_add_unless(atomic64_t *v, long long a,
long long u)

2
arch/arm64/include/asm/atomic.h
View File

@ -159,5 +159,7 @@
#define atomic64_andnot atomic64_andnot
#define atomic64_dec_if_positive atomic64_dec_if_positive
#endif
#endif

16
arch/ia64/include/asm/atomic.h
View File

@ -215,22 +215,6 @@ ATOMIC64_FETCH_OP(xor, ^)
(cmpxchg(&((v)->counter), old, new))
#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
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;
}
#define atomic_add(i,v) (void)atomic_add_return((i), (v))
#define atomic_sub(i,v) (void)atomic_sub_return((i), (v))

23
arch/parisc/include/asm/atomic.h
View File

@ -223,29 +223,6 @@ atomic64_read(const atomic64_t *v)
((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
/*
* atomic64_dec_if_positive - decrement by 1 if old value positive
* @v: pointer of type atomic_t
*
* The function returns the old value of *v minus 1, even if
* the atomic variable, v, was not decremented.
*/
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;
}
#endif /* !CONFIG_64BIT */

1
arch/powerpc/include/asm/atomic.h
View File

@ -488,6 +488,7 @@ static __inline__ long atomic64_dec_if_positive(atomic64_t *v)
return t;
}
#define atomic64_dec_if_positive atomic64_dec_if_positive
#define atomic64_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
#define atomic64_cmpxchg_relaxed(v, o, n) \

17
arch/s390/include/asm/atomic.h
View File

@ -145,23 +145,6 @@ ATOMIC64_OPS(xor)
#undef ATOMIC64_OPS
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;
}
#define atomic64_sub_return(_i, _v) atomic64_add_return(-(long)(_i), _v)
#define atomic64_fetch_sub(_i, _v) atomic64_fetch_add(-(long)(_i), _v)
#define atomic64_sub(_i, _v) atomic64_add(-(long)(_i), _v)

1
arch/sparc/include/asm/atomic_64.h
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@ -62,5 +62,6 @@ static inline int atomic_xchg(atomic_t *v, int new)
#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
long atomic64_dec_if_positive(atomic64_t *v);
#define atomic64_dec_if_positive atomic64_dec_if_positive
#endif /* !(__ARCH_SPARC64_ATOMIC__) */

1
arch/x86/include/asm/atomic64_32.h
View File

@ -254,6 +254,7 @@ static inline int arch_atomic64_inc_not_zero(atomic64_t *v)
return r;
}
#define arch_atomic64_dec_if_positive arch_atomic64_dec_if_positive
static inline long long arch_atomic64_dec_if_positive(atomic64_t *v)
{
long long r;

18
arch/x86/include/asm/atomic64_64.h
View File

@ -191,24 +191,6 @@ static inline long arch_atomic64_xchg(atomic64_t *v, long new)
return xchg(&v->counter, new);
}
/*
* arch_atomic64_dec_if_positive - decrement by 1 if old value positive
* @v: pointer of type atomic_t
*
* The function returns the old value of *v minus 1, even if
* the atomic variable, v, was not decremented.
*/
static inline long arch_atomic64_dec_if_positive(atomic64_t *v)
{
s64 dec, c = arch_atomic64_read(v);
do {
dec = c - 1;
if (unlikely(dec < 0))
break;
} while (!arch_atomic64_try_cmpxchg(v, &c, dec));
return dec;
}
static inline void arch_atomic64_and(long i, atomic64_t *v)
{
asm volatile(LOCK_PREFIX "andq %1,%0"

3
include/asm-generic/atomic-instrumented.h
View File

@ -243,11 +243,14 @@ static __always_inline bool atomic64_inc_not_zero(atomic64_t *v)
}
#endif
#ifdef arch_atomic64_dec_if_positive
#define atomic64_dec_if_positive atomic64_dec_if_positive
static __always_inline s64 atomic64_dec_if_positive(atomic64_t *v)
{
kasan_check_write(v, sizeof(*v));
return arch_atomic64_dec_if_positive(v);
}
#endif
#ifdef arch_atomic_dec_and_test
#define atomic_dec_and_test atomic_dec_and_test

1
include/asm-generic/atomic64.h
View File

@ -51,6 +51,7 @@ ATOMIC64_OPS(xor)
#undef ATOMIC64_OP
extern long long atomic64_dec_if_positive(atomic64_t *v);
#define atomic64_dec_if_positive atomic64_dec_if_positive
extern long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n);
extern long long atomic64_xchg(atomic64_t *v, long long new);
extern long long atomic64_fetch_add_unless(atomic64_t *v, long long a, long long u);

97
include/linux/atomic.h
View File

@ -683,28 +683,30 @@ static inline int atomic_fetch_andnot_release(int i, atomic_t *v)
#endif
#ifndef atomic_inc_unless_negative
static inline bool atomic_inc_unless_negative(atomic_t *p)
static inline bool atomic_inc_unless_negative(atomic_t *v)
{
int v, v1;
for (v = 0; v >= 0; v = v1) {
v1 = atomic_cmpxchg(p, v, v + 1);
if (likely(v1 == v))
return true;
}
return false;
int c = atomic_read(v);
do {
if (unlikely(c < 0))
return false;
} while (!atomic_try_cmpxchg(v, &c, c + 1));
return true;
}
#endif
#ifndef atomic_dec_unless_positive
static inline bool atomic_dec_unless_positive(atomic_t *p)
static inline bool atomic_dec_unless_positive(atomic_t *v)
{
int v, v1;
for (v = 0; v <= 0; v = v1) {
v1 = atomic_cmpxchg(p, v, v - 1);
if (likely(v1 == v))
return true;
}
return false;
int c = atomic_read(v);
do {
if (unlikely(c > 0))
return false;
} while (!atomic_try_cmpxchg(v, &c, c - 1));
return true;
}
#endif
@ -718,17 +720,14 @@ static inline bool atomic_dec_unless_positive(atomic_t *p)
#ifndef atomic_dec_if_positive
static inline int atomic_dec_if_positive(atomic_t *v)
{
int c, old, dec;
c = atomic_read(v);
for (;;) {
int dec, c = atomic_read(v);
do {
dec = c - 1;
if (unlikely(dec < 0))
break;
old = atomic_cmpxchg((v), c, dec);
if (likely(old == c))
break;
c = old;
}
} while (!atomic_try_cmpxchg(v, &c, dec));
return dec;
}
#endif
@ -1290,6 +1289,56 @@ static inline long long atomic64_fetch_andnot_release(long long i, atomic64_t *v
}
#endif
#ifndef atomic64_inc_unless_negative
static inline bool atomic64_inc_unless_negative(atomic64_t *v)
{
long long c = atomic64_read(v);
do {
if (unlikely(c < 0))
return false;
} while (!atomic64_try_cmpxchg(v, &c, c + 1));
return true;
}
#endif
#ifndef atomic64_dec_unless_positive
static inline bool atomic64_dec_unless_positive(atomic64_t *v)
{
long long c = atomic64_read(v);
do {
if (unlikely(c > 0))
return false;
} while (!atomic64_try_cmpxchg(v, &c, c - 1));
return true;
}
#endif
/*
* atomic64_dec_if_positive - decrement by 1 if old value positive
* @v: pointer of type atomic64_t
*
* The function returns the old value of *v minus 1, even if
* the atomic64 variable, v, was not decremented.
*/
#ifndef atomic64_dec_if_positive
static inline long long atomic64_dec_if_positive(atomic64_t *v)
{
long long dec, c = atomic64_read(v);
do {
dec = c - 1;
if (unlikely(dec < 0))
break;
} while (!atomic64_try_cmpxchg(v, &c, dec));
return dec;
}
#endif
#define atomic64_cond_read_relaxed(v, c) smp_cond_load_relaxed(&(v)->counter, (c))
#define atomic64_cond_read_acquire(v, c) smp_cond_load_acquire(&(v)->counter, (c))