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atomics/treewide: Make atomic_fetch_add_unless() optional

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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>
This commit is contained in:
Mark Rutland 2018-06-21 13:13:09 +01:00 committed by Ingo Molnar
parent bef828204a
commit eccc2da8c0
21 changed files with 34 additions and 231 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

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

@ -235,7 +235,7 @@ static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u)
smp_mb();
return old;
}
#define atomic_fetch_add_unless atomic_fetch_add_unless
/**
* atomic64_add_unless - add unless the number is a given value

28
arch/arc/include/asm/atomic.h
View File

@ -308,34 +308,6 @@ ATOMIC_OPS(xor, ^=, CTOP_INST_AXOR_DI_R2_R2_R3)
#undef ATOMIC_OP_RETURN
#undef ATOMIC_OP
/**
* atomic_fetch_add_unless - add unless the number is a given value
* @v: pointer of type atomic_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
*/
#define atomic_fetch_add_unless(v, a, u) \
({ \
int c, old; \
\
/* \
* Explicit full memory barrier needed before/after as \
* LLOCK/SCOND thmeselves don't provide any such semantics \
*/ \
smp_mb(); \
\
c = atomic_read(v); \
while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c)\
c = old; \
\
smp_mb(); \
\
c; \
})
#define atomic_inc(v) atomic_add(1, v)
#define atomic_dec(v) atomic_sub(1, v)

11
arch/arm/include/asm/atomic.h
View File

@ -156,6 +156,7 @@ static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
return oldval;
}
#define atomic_fetch_add_unless atomic_fetch_add_unless
#else /* ARM_ARCH_6 */
@ -215,16 +216,6 @@ static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
return ret;
}
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 /* __LINUX_ARM_ARCH__ */
#define ATOMIC_OPS(op, c_op, asm_op) \

1
arch/arm64/include/asm/atomic.h
View File

@ -125,7 +125,6 @@
#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
#define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
#define atomic_add_negative(i, v) (atomic_add_return((i), (v)) < 0)
#define atomic_fetch_add_unless(v, a, u) ___atomic_add_unless(v, a, u,)
#define atomic_andnot atomic_andnot
/*

1
arch/h8300/include/asm/atomic.h
View File

@ -106,5 +106,6 @@ static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
arch_local_irq_restore(flags);
return ret;
}
#define atomic_fetch_add_unless atomic_fetch_add_unless
#endif /* __ARCH_H8300_ATOMIC __ */

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

@ -196,6 +196,7 @@ static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
);
return __oldval;
}
#define atomic_fetch_add_unless atomic_fetch_add_unless
#define atomic_inc(v) atomic_add(1, (v))
#define atomic_dec(v) atomic_sub(1, (v))

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__ int atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
int c, old;
c = atomic_read(v);
for (;;) {
if (unlikely(c == (u)))
break;
old = atomic_cmpxchg((v), c, c + (a));
if (likely(old == c))
break;
c = old;
}
return c;
}
static __inline__ long atomic64_add_unless(atomic64_t *v, long a, long u)
{
long c, old;

15
arch/m68k/include/asm/atomic.h
View File

@ -211,19 +211,4 @@ static inline int atomic_add_negative(int i, atomic_t *v)
return c != 0;
}
static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
int c, old;
c = atomic_read(v);
for (;;) {
if (unlikely(c == (u)))
break;
old = atomic_cmpxchg((v), c, c + (a));
if (likely(old == c))
break;
c = old;
}
return c;
}
#endif /* __ARCH_M68K_ATOMIC __ */

24
arch/mips/include/asm/atomic.h
View File

@ -274,30 +274,6 @@ static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
#define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))
/**
* atomic_fetch_add_unless - add unless the number is a given value
* @v: pointer of type atomic_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 atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
int c, old;
c = atomic_read(v);
for (;;) {
if (unlikely(c == (u)))
break;
old = atomic_cmpxchg((v), c, c + (a));
if (likely(old == c))
break;
c = old;
}
return c;
}
#define atomic_dec_return(v) atomic_sub_return(1, (v))
#define atomic_inc_return(v) atomic_add_return(1, (v))

24
arch/parisc/include/asm/atomic.h
View File

@ -77,30 +77,6 @@ static __inline__ int atomic_read(const atomic_t *v)
#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
/**
* atomic_fetch_add_unless - add unless the number is a given value
* @v: pointer of type atomic_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 atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
int c, old;
c = atomic_read(v);
for (;;) {
if (unlikely(c == (u)))
break;
old = atomic_cmpxchg((v), c, c + (a));
if (likely(old == c))
break;
c = old;
}
return c;
}
#define ATOMIC_OP(op, c_op) \
static __inline__ void atomic_##op(int i, atomic_t *v) \
{ \

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

@ -248,6 +248,7 @@ static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u)
return t;
}
#define atomic_fetch_add_unless atomic_fetch_add_unless
/**
* atomic_inc_not_zero - increment unless the number is zero

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

@ -349,6 +349,7 @@ static __always_inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
: "memory");
return prev;
}
#define atomic_fetch_add_unless atomic_fetch_add_unless
#ifndef CONFIG_GENERIC_ATOMIC64
static __always_inline long __atomic64_add_unless(atomic64_t *v, long a, long u)

15
arch/s390/include/asm/atomic.h
View File

@ -90,21 +90,6 @@ static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
return __atomic_cmpxchg(&v->counter, old, new);
}
static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
int c, old;
c = atomic_read(v);
for (;;) {
if (unlikely(c == u))
break;
old = atomic_cmpxchg(v, c, c + a);
if (likely(old == c))
break;
c = old;
}
return c;
}
#define ATOMIC64_INIT(i) { (i) }
static inline long atomic64_read(const atomic64_t *v)

25
arch/sh/include/asm/atomic.h
View File

@ -45,31 +45,6 @@
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
/**
* atomic_fetch_add_unless - add unless the number is a given value
* @v: pointer of type atomic_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 atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
int c, old;
c = atomic_read(v);
for (;;) {
if (unlikely(c == (u)))
break;
old = atomic_cmpxchg((v), c, c + (a));
if (likely(old == c))
break;
c = old;
}
return c;
}
#endif /* CONFIG_CPU_J2 */
#endif /* __ASM_SH_ATOMIC_H */

2
arch/sparc/include/asm/atomic_32.h
View File

@ -30,6 +30,8 @@ int atomic_xchg(atomic_t *, int);
int atomic_fetch_add_unless(atomic_t *, int, int);
void atomic_set(atomic_t *, int);
#define atomic_fetch_add_unless atomic_fetch_add_unless
#define atomic_set_release(v, i) atomic_set((v), (i))
#define atomic_read(v) READ_ONCE((v)->counter)

15
arch/sparc/include/asm/atomic_64.h
View File

@ -89,21 +89,6 @@ static inline int atomic_xchg(atomic_t *v, int new)
return xchg(&v->counter, new);
}
static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
int c, old;
c = atomic_read(v);
for (;;) {
if (unlikely(c == (u)))
break;
old = atomic_cmpxchg((v), c, c + (a));
if (likely(old == c))
break;
c = old;
}
return c;
}
#define atomic64_cmpxchg(v, o, n) \
((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))

21
arch/x86/include/asm/atomic.h
View File

@ -253,27 +253,6 @@ static inline int arch_atomic_fetch_xor(int i, atomic_t *v)
return val;
}
/**
* arch_atomic_fetch_add_unless - add unless the number is already a given value
* @v: pointer of type atomic_t
* @a: the amount to add to v...
* @u: ...unless v is equal to u.
*
* Atomically adds @a to @v, so long as @v was not already @u.
* Returns the old value of @v.
*/
static __always_inline int arch_atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
int c = arch_atomic_read(v);
do {
if (unlikely(c == u))
break;
} while (!arch_atomic_try_cmpxchg(v, &c, c + a));
return c;
}
#ifdef CONFIG_X86_32
# include <asm/atomic64_32.h>
#else

24
arch/xtensa/include/asm/atomic.h
View File

@ -274,30 +274,6 @@ ATOMIC_OPS(xor)
#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
/**
* atomic_fetch_add_unless - add unless the number is a given value
* @v: pointer of type atomic_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 atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
int c, old;
c = atomic_read(v);
for (;;) {
if (unlikely(c == (u)))
break;
old = atomic_cmpxchg((v), c, c + (a));
if (likely(old == c))
break;
c = old;
}
return c;
}
#endif /* __KERNEL__ */
#endif /* _XTENSA_ATOMIC_H */

4
include/asm-generic/atomic-instrumented.h
View File

@ -84,12 +84,14 @@ static __always_inline bool atomic64_try_cmpxchg(atomic64_t *v, s64 *old, s64 ne
}
#endif
#ifdef arch_atomic_fetch_add_unless
#define atomic_fetch_add_unless atomic_fetch_add_unless
static __always_inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
kasan_check_write(v, sizeof(*v));
return arch_atomic_fetch_add_unless(v, a, u);
}
#endif
static __always_inline bool atomic64_add_unless(atomic64_t *v, s64 a, s64 u)
{

11
include/asm-generic/atomic.h
View File

@ -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 */

23
include/linux/atomic.h
View File

@ -521,6 +521,29 @@
#endif
#endif /* xchg_relaxed */
/**
* atomic_fetch_add_unless - add unless the number is already a given value
* @v: pointer of type atomic_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 atomic_fetch_add_unless
static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
int c = atomic_read(v);
do {
if (unlikely(c == u))
break;
} while (!atomic_try_cmpxchg(v, &c, c + a));
return c;
}
#endif
/**
* atomic_add_unless - add unless the number is already a given value
* @v: pointer of type atomic_t