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#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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