8426e1f6af
Introduce an atomic_inc_not_zero operation. Make this a special case of atomic_add_unless because lockless pagecache actually wants atomic_inc_not_negativeone due to its offset refcount. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
160 lines
3.4 KiB
C
160 lines
3.4 KiB
C
/* $Id: atomic.h,v 1.3 2001/07/25 16:15:19 bjornw Exp $ */
|
|
|
|
#ifndef __ASM_CRIS_ATOMIC__
|
|
#define __ASM_CRIS_ATOMIC__
|
|
|
|
#include <asm/system.h>
|
|
#include <asm/arch/atomic.h>
|
|
|
|
/*
|
|
* Atomic operations that C can't guarantee us. Useful for
|
|
* resource counting etc..
|
|
*/
|
|
|
|
typedef struct { volatile int counter; } atomic_t;
|
|
|
|
#define ATOMIC_INIT(i) { (i) }
|
|
|
|
#define atomic_read(v) ((v)->counter)
|
|
#define atomic_set(v,i) (((v)->counter) = (i))
|
|
|
|
/* These should be written in asm but we do it in C for now. */
|
|
|
|
static inline void atomic_add(int i, volatile atomic_t *v)
|
|
{
|
|
unsigned long flags;
|
|
cris_atomic_save(v, flags);
|
|
v->counter += i;
|
|
cris_atomic_restore(v, flags);
|
|
}
|
|
|
|
static inline void atomic_sub(int i, volatile atomic_t *v)
|
|
{
|
|
unsigned long flags;
|
|
cris_atomic_save(v, flags);
|
|
v->counter -= i;
|
|
cris_atomic_restore(v, flags);
|
|
}
|
|
|
|
static inline int atomic_add_return(int i, volatile atomic_t *v)
|
|
{
|
|
unsigned long flags;
|
|
int retval;
|
|
cris_atomic_save(v, flags);
|
|
retval = (v->counter += i);
|
|
cris_atomic_restore(v, flags);
|
|
return retval;
|
|
}
|
|
|
|
#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
|
|
|
|
static inline int atomic_sub_return(int i, volatile atomic_t *v)
|
|
{
|
|
unsigned long flags;
|
|
int retval;
|
|
cris_atomic_save(v, flags);
|
|
retval = (v->counter -= i);
|
|
cris_atomic_restore(v, flags);
|
|
return retval;
|
|
}
|
|
|
|
static inline int atomic_sub_and_test(int i, volatile atomic_t *v)
|
|
{
|
|
int retval;
|
|
unsigned long flags;
|
|
cris_atomic_save(v, flags);
|
|
retval = (v->counter -= i) == 0;
|
|
cris_atomic_restore(v, flags);
|
|
return retval;
|
|
}
|
|
|
|
static inline void atomic_inc(volatile atomic_t *v)
|
|
{
|
|
unsigned long flags;
|
|
cris_atomic_save(v, flags);
|
|
(v->counter)++;
|
|
cris_atomic_restore(v, flags);
|
|
}
|
|
|
|
static inline void atomic_dec(volatile atomic_t *v)
|
|
{
|
|
unsigned long flags;
|
|
cris_atomic_save(v, flags);
|
|
(v->counter)--;
|
|
cris_atomic_restore(v, flags);
|
|
}
|
|
|
|
static inline int atomic_inc_return(volatile atomic_t *v)
|
|
{
|
|
unsigned long flags;
|
|
int retval;
|
|
cris_atomic_save(v, flags);
|
|
retval = (v->counter)++;
|
|
cris_atomic_restore(v, flags);
|
|
return retval;
|
|
}
|
|
|
|
static inline int atomic_dec_return(volatile atomic_t *v)
|
|
{
|
|
unsigned long flags;
|
|
int retval;
|
|
cris_atomic_save(v, flags);
|
|
retval = (v->counter)--;
|
|
cris_atomic_restore(v, flags);
|
|
return retval;
|
|
}
|
|
static inline int atomic_dec_and_test(volatile atomic_t *v)
|
|
{
|
|
int retval;
|
|
unsigned long flags;
|
|
cris_atomic_save(v, flags);
|
|
retval = --(v->counter) == 0;
|
|
cris_atomic_restore(v, flags);
|
|
return retval;
|
|
}
|
|
|
|
static inline int atomic_inc_and_test(volatile atomic_t *v)
|
|
{
|
|
int retval;
|
|
unsigned long flags;
|
|
cris_atomic_save(v, flags);
|
|
retval = ++(v->counter) == 0;
|
|
cris_atomic_restore(v, flags);
|
|
return retval;
|
|
}
|
|
|
|
static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
|
|
{
|
|
int ret;
|
|
unsigned long flags;
|
|
|
|
cris_atomic_save(v, flags);
|
|
ret = v->counter;
|
|
if (likely(ret == old))
|
|
v->counter = new;
|
|
cris_atomic_restore(v, flags);
|
|
return ret;
|
|
}
|
|
|
|
static inline int atomic_add_unless(atomic_t *v, int a, int u)
|
|
{
|
|
int ret;
|
|
unsigned long flags;
|
|
|
|
cris_atomic_save(v, flags);
|
|
ret = v->counter;
|
|
if (ret != u)
|
|
v->counter += a;
|
|
cris_atomic_restore(v, flags);
|
|
return ret != u;
|
|
}
|
|
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
|
|
|
|
/* Atomic operations are already serializing */
|
|
#define smp_mb__before_atomic_dec() barrier()
|
|
#define smp_mb__after_atomic_dec() barrier()
|
|
#define smp_mb__before_atomic_inc() barrier()
|
|
#define smp_mb__after_atomic_inc() barrier()
|
|
|
|
#endif
|