atomics/generic: Define atomic64_fetch_add_unless() (00b808ab) · Commits · 戴 / test

As a step towards unifying the atomic/atomic64/atomic_long APIs, this patch converts the generic implementation of atomic64_add_unless() into a generic 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: Arnd Bergmann <arnd@arndb.de> 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/20180621121321.4761-9-mark.rutland@arm.com Signed-off-by:

Ingo Molnar <mingo@kernel.org>

include/asm-generic/atomic64.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -53,7 +53,8 @@ ATOMIC64_OPS(xor)
		extern long long atomic64_dec_if_positive(atomic64_t *v);
		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 bool atomic64_add_unless(atomic64_t *v, long long a, long long u);
		extern long long atomic64_fetch_add_unless(atomic64_t *v, long long a, long long u);
		#define atomic64_fetch_add_unless atomic64_fetch_add_unless

		#define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)
		#define atomic64_inc(v) atomic64_add(1LL, (v))

lib/atomic64.c

+7 −7

Original line number	Diff line number	Diff line
		@@ -178,18 +178,18 @@ long long atomic64_xchg(atomic64_t *v, long long new)
		}
		EXPORT_SYMBOL(atomic64_xchg);

		bool atomic64_add_unless(atomic64_t *v, long long a, long long u)
		long long atomic64_fetch_add_unless(atomic64_t *v, long long a, long long u)
		{
		unsigned long flags;
		raw_spinlock_t *lock = lock_addr(v);
		bool ret = false;
		long long val;

		raw_spin_lock_irqsave(lock, flags);
		if (v->counter != u) {
		val = v->counter;
		if (val != u)
		v->counter += a;
		ret = true;
		}
		raw_spin_unlock_irqrestore(lock, flags);
		return ret;

		return val;
		}
		EXPORT_SYMBOL(atomic64_add_unless);
		EXPORT_SYMBOL(atomic64_fetch_add_unless);

Admin message