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>
156 lines
3.3 KiB
C
156 lines
3.3 KiB
C
#ifndef __ASM_SH64_ATOMIC_H
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#define __ASM_SH64_ATOMIC_H
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/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* include/asm-sh64/atomic.h
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*
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* Copyright (C) 2000, 2001 Paolo Alberelli
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* Copyright (C) 2003 Paul Mundt
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*
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*/
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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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*/
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typedef struct { volatile int counter; } atomic_t;
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#define ATOMIC_INIT(i) ( (atomic_t) { (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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#include <asm/system.h>
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/*
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* To get proper branch prediction for the main line, we must branch
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* forward to code at the end of this object's .text section, then
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* branch back to restart the operation.
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*/
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static __inline__ void atomic_add(int i, atomic_t * v)
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{
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unsigned long flags;
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local_irq_save(flags);
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*(long *)v += i;
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local_irq_restore(flags);
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}
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static __inline__ void atomic_sub(int i, atomic_t *v)
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{
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unsigned long flags;
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local_irq_save(flags);
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*(long *)v -= i;
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local_irq_restore(flags);
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}
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static __inline__ int atomic_add_return(int i, atomic_t * v)
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{
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unsigned long temp, flags;
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local_irq_save(flags);
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temp = *(long *)v;
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temp += i;
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*(long *)v = temp;
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local_irq_restore(flags);
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return temp;
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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, atomic_t * v)
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{
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unsigned long temp, flags;
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local_irq_save(flags);
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temp = *(long *)v;
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temp -= i;
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*(long *)v = temp;
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local_irq_restore(flags);
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return temp;
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}
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#define atomic_dec_return(v) atomic_sub_return(1,(v))
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#define atomic_inc_return(v) atomic_add_return(1,(v))
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/*
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* atomic_inc_and_test - increment and test
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1
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* and returns true if the result is zero, or false for all
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* other cases.
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*/
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#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
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#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
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#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
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#define atomic_inc(v) atomic_add(1,(v))
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#define atomic_dec(v) atomic_sub(1,(v))
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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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local_irq_save(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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local_irq_restore(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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local_irq_save(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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local_irq_restore(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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static __inline__ void atomic_clear_mask(unsigned int mask, atomic_t *v)
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{
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unsigned long flags;
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local_irq_save(flags);
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*(long *)v &= ~mask;
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local_irq_restore(flags);
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}
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static __inline__ void atomic_set_mask(unsigned int mask, atomic_t *v)
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{
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unsigned long flags;
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local_irq_save(flags);
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*(long *)v |= mask;
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local_irq_restore(flags);
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}
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/* Atomic operations are already serializing on SH */
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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 /* __ASM_SH64_ATOMIC_H */
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