Current File : //usr/src/kernels/3.10.0-1160.81.1.el7.centos.plus.x86_64/include/linux/lockref.h
#ifndef __LINUX_LOCKREF_H
#define __LINUX_LOCKREF_H
#include <linux/rh_kabi.h>
/*
* Locked reference counts.
*
* These are different from just plain atomic refcounts in that they
* are atomic with respect to the spinlock that goes with them. In
* particular, there can be implementations that don't actually get
* the spinlock for the common decrement/increment operations, but they
* still have to check that the operation is done semantically as if
* the spinlock had been taken (using a cmpxchg operation that covers
* both the lock and the count word, or using memory transactions, for
* example).
*/
#include <linux/spinlock.h>
struct lockref {
union {
#if defined(CONFIG_PPC64) || defined(CONFIG_S390)
#ifdef CONFIG_CMPXCHG_LOCKREF
RH_KABI_EXTEND(aligned_u64 lock_count)
#endif
#else /* CONFIG_PPC64 || CONFIG_S390 */
#ifdef CONFIG_CMPXCHG_LOCKREF
aligned_u64 lock_count;
#endif
#endif /* CONFIG_PPC64 */
struct {
spinlock_t lock;
unsigned int count;
};
};
};
extern void lockref_get(struct lockref *);
extern int lockref_get_not_zero(struct lockref *);
extern int lockref_get_or_lock(struct lockref *);
extern int lockref_put_or_lock(struct lockref *);
extern void lockref_mark_dead(struct lockref *);
extern int lockref_get_not_dead(struct lockref *);
/* Must be called under spinlock for reliable results */
static inline int __lockref_is_dead(const struct lockref *l)
{
return ((int)l->count < 0);
}
#endif /* __LINUX_LOCKREF_H */
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