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atomics/treewide: Make test ops optional

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Some of the atomics return the result of a test applied after the atomic
operation, and almost all architectures implement these as trivial
wrappers around the underlying atomic. Specifically:

 * <atomic>_inc_and_test(v)    is (<atomic>_inc_return(v)    == 0)
 * <atomic>_dec_and_test(v)    is (<atomic>_dec_return(v)    == 0)
 * <atomic>_sub_and_test(i, v) is (<atomic>_sub_return(i, v) == 0)
 * <atomic>_add_negative(i, v) is (<atomic>_add_return(i, v)  < 0)

Rather than have these definitions duplicated in all architectures, with
minor inconsistencies in formatting and documentation, let's make these
operations optional, with default fallbacks as above. Implementations
must now provide a preprocessor symbol.

The instrumented atomics are updated accordingly.

Both x86 and m68k have custom implementations, which are left as-is,
given preprocessor symbols to avoid being overridden.

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: 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>
Link: https://lore.kernel.org/lkml/20180621121321.4761-16-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Mark Rutland
2018-06-21 13:13:18 +01:00
committed by Ingo Molnar
parent 356701329f
commit 18cc1814d4
24 changed files with 160 additions and 410 deletions
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30
arch/powerpc/include/asm/atomic.h
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@@ -129,8 +129,6 @@ ATOMIC_OPS(xor, xor)
#undef ATOMIC_OP_RETURN_RELAXED
#undef ATOMIC_OP
#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
static __inline__ void atomic_inc(atomic_t *v)
{
int t;
@@ -163,16 +161,6 @@ static __inline__ int atomic_inc_return_relaxed(atomic_t *v)
return t;
}
/*
* atomic_inc_and_test - increment and test
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
static __inline__ void atomic_dec(atomic_t *v)
{
int t;
@@ -281,9 +269,6 @@ static __inline__ int atomic_inc_not_zero(atomic_t *v)
}
#define atomic_inc_not_zero(v) atomic_inc_not_zero((v))
#define atomic_sub_and_test(a, v) (atomic_sub_return((a), (v)) == 0)
#define atomic_dec_and_test(v) (atomic_dec_return((v)) == 0)
/*
* Atomically test *v and decrement if it is greater than 0.
* The function returns the old value of *v minus 1, even if
@@ -413,8 +398,6 @@ ATOMIC64_OPS(xor, xor)
#undef ATOMIC64_OP_RETURN_RELAXED
#undef ATOMIC64_OP
#define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)
static __inline__ void atomic64_inc(atomic64_t *v)
{
long t;
@@ -445,16 +428,6 @@ static __inline__ long atomic64_inc_return_relaxed(atomic64_t *v)
return t;
}
/*
* atomic64_inc_and_test - increment and test
* @v: pointer of type atomic64_t
*
* Atomically increments @v by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
#define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0)
static __inline__ void atomic64_dec(atomic64_t *v)
{
long t;
@@ -488,9 +461,6 @@ static __inline__ long atomic64_dec_return_relaxed(atomic64_t *v)
#define atomic64_inc_return_relaxed atomic64_inc_return_relaxed
#define atomic64_dec_return_relaxed atomic64_dec_return_relaxed
#define atomic64_sub_and_test(a, v) (atomic64_sub_return((a), (v)) == 0)
#define atomic64_dec_and_test(v) (atomic64_dec_return((v)) == 0)
/*
* Atomically test *v and decrement if it is greater than 0.
* The function returns the old value of *v minus 1.