You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
197 lines
4.1 KiB
197 lines
4.1 KiB
/* SPDX-License-Identifier: GPL-2.0-or-later */
|
|
/*
|
|
* Generic C implementation of atomic counter operations. Usable on
|
|
* UP systems only. Do not include in machine independent code.
|
|
*
|
|
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*/
|
|
#ifndef __ASM_GENERIC_ATOMIC_H
|
|
#define __ASM_GENERIC_ATOMIC_H
|
|
|
|
#include <asm/cmpxchg.h>
|
|
#include <asm/barrier.h>
|
|
|
|
/*
|
|
* atomic_$op() - $op integer to atomic variable
|
|
* @i: integer value to $op
|
|
* @v: pointer to the atomic variable
|
|
*
|
|
* Atomically $ops @i to @v. Does not strictly guarantee a memory-barrier, use
|
|
* smp_mb__{before,after}_atomic().
|
|
*/
|
|
|
|
/*
|
|
* atomic_$op_return() - $op interer to atomic variable and returns the result
|
|
* @i: integer value to $op
|
|
* @v: pointer to the atomic variable
|
|
*
|
|
* Atomically $ops @i to @v. Does imply a full memory barrier.
|
|
*/
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
/* we can build all atomic primitives from cmpxchg */
|
|
|
|
#define ATOMIC_OP(op, c_op) \
|
|
static inline void atomic_##op(int i, atomic_t *v) \
|
|
{ \
|
|
int c, old; \
|
|
\
|
|
c = v->counter; \
|
|
while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
|
|
c = old; \
|
|
}
|
|
|
|
#define ATOMIC_OP_RETURN(op, c_op) \
|
|
static inline int atomic_##op##_return(int i, atomic_t *v) \
|
|
{ \
|
|
int c, old; \
|
|
\
|
|
c = v->counter; \
|
|
while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
|
|
c = old; \
|
|
\
|
|
return c c_op i; \
|
|
}
|
|
|
|
#define ATOMIC_FETCH_OP(op, c_op) \
|
|
static inline int atomic_fetch_##op(int i, atomic_t *v) \
|
|
{ \
|
|
int c, old; \
|
|
\
|
|
c = v->counter; \
|
|
while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
|
|
c = old; \
|
|
\
|
|
return c; \
|
|
}
|
|
|
|
#else
|
|
|
|
#include <linux/irqflags.h>
|
|
|
|
#define ATOMIC_OP(op, c_op) \
|
|
static inline void atomic_##op(int i, atomic_t *v) \
|
|
{ \
|
|
unsigned long flags; \
|
|
\
|
|
raw_local_irq_save(flags); \
|
|
v->counter = v->counter c_op i; \
|
|
raw_local_irq_restore(flags); \
|
|
}
|
|
|
|
#define ATOMIC_OP_RETURN(op, c_op) \
|
|
static inline int atomic_##op##_return(int i, atomic_t *v) \
|
|
{ \
|
|
unsigned long flags; \
|
|
int ret; \
|
|
\
|
|
raw_local_irq_save(flags); \
|
|
ret = (v->counter = v->counter c_op i); \
|
|
raw_local_irq_restore(flags); \
|
|
\
|
|
return ret; \
|
|
}
|
|
|
|
#define ATOMIC_FETCH_OP(op, c_op) \
|
|
static inline int atomic_fetch_##op(int i, atomic_t *v) \
|
|
{ \
|
|
unsigned long flags; \
|
|
int ret; \
|
|
\
|
|
raw_local_irq_save(flags); \
|
|
ret = v->counter; \
|
|
v->counter = v->counter c_op i; \
|
|
raw_local_irq_restore(flags); \
|
|
\
|
|
return ret; \
|
|
}
|
|
|
|
#endif /* CONFIG_SMP */
|
|
|
|
#ifndef atomic_add_return
|
|
ATOMIC_OP_RETURN(add, +)
|
|
#endif
|
|
|
|
#ifndef atomic_sub_return
|
|
ATOMIC_OP_RETURN(sub, -)
|
|
#endif
|
|
|
|
#ifndef atomic_fetch_add
|
|
ATOMIC_FETCH_OP(add, +)
|
|
#endif
|
|
|
|
#ifndef atomic_fetch_sub
|
|
ATOMIC_FETCH_OP(sub, -)
|
|
#endif
|
|
|
|
#ifndef atomic_fetch_and
|
|
ATOMIC_FETCH_OP(and, &)
|
|
#endif
|
|
|
|
#ifndef atomic_fetch_or
|
|
ATOMIC_FETCH_OP(or, |)
|
|
#endif
|
|
|
|
#ifndef atomic_fetch_xor
|
|
ATOMIC_FETCH_OP(xor, ^)
|
|
#endif
|
|
|
|
#ifndef atomic_and
|
|
ATOMIC_OP(and, &)
|
|
#endif
|
|
|
|
#ifndef atomic_or
|
|
ATOMIC_OP(or, |)
|
|
#endif
|
|
|
|
#ifndef atomic_xor
|
|
ATOMIC_OP(xor, ^)
|
|
#endif
|
|
|
|
#undef ATOMIC_FETCH_OP
|
|
#undef ATOMIC_OP_RETURN
|
|
#undef ATOMIC_OP
|
|
|
|
/*
|
|
* Atomic operations that C can't guarantee us. Useful for
|
|
* resource counting etc..
|
|
*/
|
|
|
|
/**
|
|
* atomic_read - read atomic variable
|
|
* @v: pointer of type atomic_t
|
|
*
|
|
* Atomically reads the value of @v.
|
|
*/
|
|
#ifndef atomic_read
|
|
#define atomic_read(v) READ_ONCE((v)->counter)
|
|
#endif
|
|
|
|
/**
|
|
* atomic_set - set atomic variable
|
|
* @v: pointer of type atomic_t
|
|
* @i: required value
|
|
*
|
|
* Atomically sets the value of @v to @i.
|
|
*/
|
|
#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
|
|
|
|
#include <linux/irqflags.h>
|
|
|
|
static inline void atomic_add(int i, atomic_t *v)
|
|
{
|
|
atomic_add_return(i, v);
|
|
}
|
|
|
|
static inline void atomic_sub(int i, atomic_t *v)
|
|
{
|
|
atomic_sub_return(i, v);
|
|
}
|
|
|
|
#define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
|
|
#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
|
|
|
|
#endif /* __ASM_GENERIC_ATOMIC_H */
|