7ee1f8e3ab
Improve support for writing to XFS partitions. Work done by: Russell Cattelan <cattelan at xfs dot org>
37 lines
930 B
C
37 lines
930 B
C
#ifndef __XFS_SUPPORT_ATOMIC_H__
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#include <sys/types.h>
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#include <machine/atomic.h>
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typedef struct {
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volatile unsigned int val;
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} atomic_t;
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#define atomic_read(v) ((v)->val)
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#define atomic_set(v, i) ((v)->val = (i))
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#define atomic_add(i, v) atomic_add_int(&(v)->val, (i))
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#define atomic_inc(v) atomic_add_int(&(v)->val, 1)
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#define atomic_dec(v) atomic_subtract_int(&(v)->val, 1)
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#define atomic_sub(i, v) atomic_subtract_int(&(v)->val, (i))
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#define atomic_dec_and_test(v) (atomic_fetchadd_int(&(v)->val, -1) == 1)
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/*
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* This is used for two variables in XFS, one of which is a debug trace
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* buffer index.
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*/
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static __inline__ int atomicIncWithWrap(volatile unsigned int *ip, int val)
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{
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unsigned int oldval, newval;
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do {
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oldval = *ip;
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newval = (oldval + 1 >= val) ? 0 : oldval + 1;
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} while (atomic_cmpset_rel_int(ip, oldval, newval) == 0);
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return oldval;
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}
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#endif /* __XFS_SUPPORT_ATOMIC_H__ */
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