linux/include/asm-h8300/atomic.h
Nick Piggin 8426e1f6af [PATCH] atomic: inc_not_zero
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>
2005-11-13 18:14:16 -08:00

141 lines
3.2 KiB
C

#ifndef __ARCH_H8300_ATOMIC__
#define __ARCH_H8300_ATOMIC__
/*
* Atomic operations that C can't guarantee us. Useful for
* resource counting etc..
*/
typedef struct { int counter; } atomic_t;
#define ATOMIC_INIT(i) { (i) }
#define atomic_read(v) ((v)->counter)
#define atomic_set(v, i) (((v)->counter) = i)
#include <asm/system.h>
#include <linux/kernel.h>
static __inline__ int atomic_add_return(int i, atomic_t *v)
{
int ret,flags;
local_irq_save(flags);
ret = v->counter += i;
local_irq_restore(flags);
return ret;
}
#define atomic_add(i, v) atomic_add_return(i, v)
#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
static __inline__ int atomic_sub_return(int i, atomic_t *v)
{
int ret,flags;
local_irq_save(flags);
ret = v->counter -= i;
local_irq_restore(flags);
return ret;
}
#define atomic_sub(i, v) atomic_sub_return(i, v)
static __inline__ int atomic_inc_return(atomic_t *v)
{
int ret,flags;
local_irq_save(flags);
v->counter++;
ret = v->counter;
local_irq_restore(flags);
return ret;
}
#define atomic_inc(v) atomic_inc_return(v)
/*
* atomic_inc_and_test - increment and test
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
static __inline__ int atomic_dec_return(atomic_t *v)
{
int ret,flags;
local_irq_save(flags);
--v->counter;
ret = v->counter;
local_irq_restore(flags);
return ret;
}
#define atomic_dec(v) atomic_dec_return(v)
static __inline__ int atomic_dec_and_test(atomic_t *v)
{
int ret,flags;
local_irq_save(flags);
--v->counter;
ret = v->counter;
local_irq_restore(flags);
return ret == 0;
}
static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
{
int ret;
unsigned long flags;
local_irq_save(flags);
ret = v->counter;
if (likely(ret == old))
v->counter = new;
local_irq_restore(flags);
return ret;
}
static inline int atomic_add_unless(atomic_t *v, int a, int u)
{
int ret;
unsigned long flags;
local_irq_save(flags);
ret = v->counter;
if (ret != u)
v->counter += a;
local_irq_restore(flags);
return ret != u;
}
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
static __inline__ void atomic_clear_mask(unsigned long mask, unsigned long *v)
{
__asm__ __volatile__("stc ccr,r1l\n\t"
"orc #0x80,ccr\n\t"
"mov.l %0,er0\n\t"
"and.l %1,er0\n\t"
"mov.l er0,%0\n\t"
"ldc r1l,ccr"
: "=m" (*v) : "g" (~(mask)) :"er0","er1");
}
static __inline__ void atomic_set_mask(unsigned long mask, unsigned long *v)
{
__asm__ __volatile__("stc ccr,r1l\n\t"
"orc #0x80,ccr\n\t"
"mov.l %0,er0\n\t"
"or.l %1,er0\n\t"
"mov.l er0,%0\n\t"
"ldc r1l,ccr"
: "=m" (*v) : "g" (mask) :"er0","er1");
}
/* 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 /* __ARCH_H8300_ATOMIC __ */