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atomics/alpha: Define atomic64_fetch_add_unless() 

As a step towards unifying the atomic/atomic64/atomic_long APIs, this
patch converts the arch/alpha implementation of atomic64_add_unless() into
an implementation of atomic64_fetch_add_unless().

A wrapper in <linux/atomic.h> will build atomic_add_unless() atop of
this, provided it is given a preprocessor definition.

No functional change is intended 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: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20180621121321.4761-10-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Mark Rutland 2018-06-21 13:13:12 +01:00 committed by Ingo Molnar
parent 00b808ab79
commit 434b6acc31
1 changed files with 12 additions and 11 deletions
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23
arch/alpha/include/asm/atomic.h
View File

@ -238,35 +238,36 @@ static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u)
#define atomic_fetch_add_unless atomic_fetch_add_unless
/**
* atomic64_add_unless - add unless the number is a given value
* atomic64_fetch_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.
* Returns the old value of @v.
*/
static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
static __inline__ long atomic64_fetch_add_unless(atomic64_t *v, long a, long u)
{
long c, tmp;
long c, new, old;
smp_mb();
__asm__ __volatile__(
"1: ldq_l %[tmp],%[mem]\n"
" cmpeq %[tmp],%[u],%[c]\n"
" addq %[tmp],%[a],%[tmp]\n"
"1: ldq_l %[old],%[mem]\n"
" cmpeq %[old],%[u],%[c]\n"
" addq %[old],%[a],%[new]\n"
" bne %[c],2f\n"
" stq_c %[tmp],%[mem]\n"
" beq %[tmp],3f\n"
" stq_c %[new],%[mem]\n"
" beq %[new],3f\n"
"2:\n"
".subsection 2\n"
"3: br 1b\n"
".previous"
: [tmp] "=&r"(tmp), [c] "=&r"(c)
: [old] "=&r"(old), [new] "=&r"(new), [c] "=&r"(c)
: [mem] "m"(*v), [a] "rI"(a), [u] "rI"(u)
: "memory");
smp_mb();
return !c;
return old;
}
#define atomic64_fetch_add_unless atomic64_fetch_add_unless
/*
* atomic64_dec_if_positive - decrement by 1 if old value positive