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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 $ */
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#ifndef __ASM_CRIS_ATOMIC__
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#define __ASM_CRIS_ATOMIC__
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#include <asm/system.h>
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#include <asm/arch/atomic.h>
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/*
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* Atomic operations that C can't guarantee us. Useful for
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* resource counting etc..
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*/
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typedef struct { volatile int counter; } atomic_t;
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#define ATOMIC_INIT(i) { (i) }
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#define atomic_read(v) ((v)->counter)
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#define atomic_set(v,i) (((v)->counter) = (i))
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/* These should be written in asm but we do it in C for now. */
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static inline void atomic_add(int i, volatile atomic_t *v)
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{
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unsigned long flags;
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cris_atomic_save(v, flags);
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v->counter += i;
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cris_atomic_restore(v, flags);
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}
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static inline void atomic_sub(int i, volatile atomic_t *v)
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{
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unsigned long flags;
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cris_atomic_save(v, flags);
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v->counter -= i;
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cris_atomic_restore(v, flags);
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}
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static inline int atomic_add_return(int i, volatile atomic_t *v)
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{
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unsigned long flags;
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int retval;
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cris_atomic_save(v, flags);
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retval = (v->counter += i);
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cris_atomic_restore(v, flags);
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return retval;
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}
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#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
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static inline int atomic_sub_return(int i, volatile atomic_t *v)
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{
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unsigned long flags;
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int retval;
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cris_atomic_save(v, flags);
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retval = (v->counter -= i);
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cris_atomic_restore(v, flags);
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return retval;
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}
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static inline int atomic_sub_and_test(int i, volatile atomic_t *v)
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{
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int retval;
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unsigned long flags;
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cris_atomic_save(v, flags);
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retval = (v->counter -= i) == 0;
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cris_atomic_restore(v, flags);
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return retval;
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}
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static inline void atomic_inc(volatile atomic_t *v)
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{
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unsigned long flags;
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cris_atomic_save(v, flags);
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(v->counter)++;
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cris_atomic_restore(v, flags);
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}
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static inline void atomic_dec(volatile atomic_t *v)
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{
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unsigned long flags;
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cris_atomic_save(v, flags);
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(v->counter)--;
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cris_atomic_restore(v, flags);
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}
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static inline int atomic_inc_return(volatile atomic_t *v)
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{
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unsigned long flags;
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int retval;
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cris_atomic_save(v, flags);
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retval = (v->counter)++;
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cris_atomic_restore(v, flags);
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return retval;
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}
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static inline int atomic_dec_return(volatile atomic_t *v)
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{
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unsigned long flags;
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int retval;
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cris_atomic_save(v, flags);
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retval = (v->counter)--;
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cris_atomic_restore(v, flags);
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return retval;
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}
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static inline int atomic_dec_and_test(volatile atomic_t *v)
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{
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int retval;
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unsigned long flags;
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cris_atomic_save(v, flags);
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retval = --(v->counter) == 0;
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cris_atomic_restore(v, flags);
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return retval;
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}
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static inline int atomic_inc_and_test(volatile atomic_t *v)
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{
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int retval;
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unsigned long flags;
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cris_atomic_save(v, flags);
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retval = ++(v->counter) == 0;
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cris_atomic_restore(v, flags);
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return retval;
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}
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static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
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{
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int ret;
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unsigned long flags;
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cris_atomic_save(v, flags);
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ret = v->counter;
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if (likely(ret == old))
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v->counter = new;
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cris_atomic_restore(v, flags);
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return ret;
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}
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static inline int atomic_add_unless(atomic_t *v, int a, int u)
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{
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int ret;
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unsigned long flags;
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cris_atomic_save(v, flags);
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ret = v->counter;
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if (ret != u)
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v->counter += a;
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cris_atomic_restore(v, flags);
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return ret != u;
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}
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#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
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/* Atomic operations are already serializing */
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#define smp_mb__before_atomic_dec() barrier()
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#define smp_mb__after_atomic_dec() barrier()
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#define smp_mb__before_atomic_inc() barrier()
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#define smp_mb__after_atomic_inc() barrier()
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#endif
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