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linux/arch/alpha/include/asm/local.h
Uros Bizjak 5e0eb67974 locking/local, arch: Rewrite local_add_unless() as a static inline function
Rewrite local_add_unless() as a static inline function with boolean
return value, similar to the arch_atomic_add_unless() arch fallbacks.

The function is currently unused.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230731084458.28096-1-ubizjak@gmail.com
2023-10-04 11:38:11 +02:00

110 lines
2.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ALPHA_LOCAL_H
#define _ALPHA_LOCAL_H
#include <linux/percpu.h>
#include <linux/atomic.h>
typedef struct
{
atomic_long_t a;
} local_t;
#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
#define local_read(l) atomic_long_read(&(l)->a)
#define local_set(l,i) atomic_long_set(&(l)->a, (i))
#define local_inc(l) atomic_long_inc(&(l)->a)
#define local_dec(l) atomic_long_dec(&(l)->a)
#define local_add(i,l) atomic_long_add((i),(&(l)->a))
#define local_sub(i,l) atomic_long_sub((i),(&(l)->a))
static __inline__ long local_add_return(long i, local_t * l)
{
long temp, result;
__asm__ __volatile__(
"1: ldq_l %0,%1\n"
" addq %0,%3,%2\n"
" addq %0,%3,%0\n"
" stq_c %0,%1\n"
" beq %0,2f\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
:"=&r" (temp), "=m" (l->a.counter), "=&r" (result)
:"Ir" (i), "m" (l->a.counter) : "memory");
return result;
}
static __inline__ long local_sub_return(long i, local_t * l)
{
long temp, result;
__asm__ __volatile__(
"1: ldq_l %0,%1\n"
" subq %0,%3,%2\n"
" subq %0,%3,%0\n"
" stq_c %0,%1\n"
" beq %0,2f\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
:"=&r" (temp), "=m" (l->a.counter), "=&r" (result)
:"Ir" (i), "m" (l->a.counter) : "memory");
return result;
}
static __inline__ long local_cmpxchg(local_t *l, long old, long new)
{
return cmpxchg_local(&l->a.counter, old, new);
}
static __inline__ bool local_try_cmpxchg(local_t *l, long *old, long new)
{
return try_cmpxchg_local(&l->a.counter, (s64 *)old, new);
}
#define local_xchg(l, n) (xchg_local(&((l)->a.counter), (n)))
/**
* local_add_unless - add unless the number is already a given value
* @l: pointer of type local_t
* @a: the amount to add to l...
* @u: ...unless l is equal to u.
*
* Atomically adds @a to @l, if @v was not already @u.
* Returns true if the addition was done.
*/
static __inline__ bool
local_add_unless(local_t *l, long a, long u)
{
long c = local_read(l);
do {
if (unlikely(c == u))
return false;
} while (!local_try_cmpxchg(l, &c, c + a));
return true;
}
#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
#define local_add_negative(a, l) (local_add_return((a), (l)) < 0)
#define local_dec_return(l) local_sub_return(1,(l))
#define local_inc_return(l) local_add_return(1,(l))
#define local_sub_and_test(i,l) (local_sub_return((i), (l)) == 0)
#define local_inc_and_test(l) (local_add_return(1, (l)) == 0)
#define local_dec_and_test(l) (local_sub_return(1, (l)) == 0)
/* Verify if faster than atomic ops */
#define __local_inc(l) ((l)->a.counter++)
#define __local_dec(l) ((l)->a.counter++)
#define __local_add(i,l) ((l)->a.counter+=(i))
#define __local_sub(i,l) ((l)->a.counter-=(i))
#endif /* _ALPHA_LOCAL_H */