Fetching contributors…
Cannot retrieve contributors at this time
119 lines (95 sloc) 3.15 KB
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/atomic.h>
#include <linux/compiler.h>
#include <linux/spinlock_types.h>
struct mutex;
* struct refcount_t - variant of atomic_t specialized for reference counts
* @refs: atomic_t counter field
* The counter saturates at UINT_MAX and will not move once
* there. This avoids wrapping the counter and causing 'spurious'
* use-after-free bugs.
typedef struct refcount_struct {
atomic_t refs;
} refcount_t;
#define REFCOUNT_INIT(n) { .refs = ATOMIC_INIT(n), }
* refcount_set - set a refcount's value
* @r: the refcount
* @n: value to which the refcount will be set
static inline void refcount_set(refcount_t *r, unsigned int n)
atomic_set(&r->refs, n);
* refcount_read - get a refcount's value
* @r: the refcount
* Return: the refcount's value
static inline unsigned int refcount_read(const refcount_t *r)
return atomic_read(&r->refs);
extern __must_check bool refcount_add_not_zero_checked(unsigned int i, refcount_t *r);
extern void refcount_add_checked(unsigned int i, refcount_t *r);
extern __must_check bool refcount_inc_not_zero_checked(refcount_t *r);
extern void refcount_inc_checked(refcount_t *r);
extern __must_check bool refcount_sub_and_test_checked(unsigned int i, refcount_t *r);
extern __must_check bool refcount_dec_and_test_checked(refcount_t *r);
extern void refcount_dec_checked(refcount_t *r);
#define refcount_add_not_zero refcount_add_not_zero_checked
#define refcount_add refcount_add_checked
#define refcount_inc_not_zero refcount_inc_not_zero_checked
#define refcount_inc refcount_inc_checked
#define refcount_sub_and_test refcount_sub_and_test_checked
#define refcount_dec_and_test refcount_dec_and_test_checked
#define refcount_dec refcount_dec_checked
# include <asm/refcount.h>
# else
static inline __must_check bool refcount_add_not_zero(unsigned int i, refcount_t *r)
return atomic_add_unless(&r->refs, i, 0);
static inline void refcount_add(unsigned int i, refcount_t *r)
atomic_add(i, &r->refs);
static inline __must_check bool refcount_inc_not_zero(refcount_t *r)
return atomic_add_unless(&r->refs, 1, 0);
static inline void refcount_inc(refcount_t *r)
static inline __must_check bool refcount_sub_and_test(unsigned int i, refcount_t *r)
return atomic_sub_and_test(i, &r->refs);
static inline __must_check bool refcount_dec_and_test(refcount_t *r)
return atomic_dec_and_test(&r->refs);
static inline void refcount_dec(refcount_t *r)
extern __must_check bool refcount_dec_if_one(refcount_t *r);
extern __must_check bool refcount_dec_not_one(refcount_t *r);
extern __must_check bool refcount_dec_and_mutex_lock(refcount_t *r, struct mutex *lock);
extern __must_check bool refcount_dec_and_lock(refcount_t *r, spinlock_t *lock);
extern __must_check bool refcount_dec_and_lock_irqsave(refcount_t *r,
spinlock_t *lock,
unsigned long *flags);
#endif /* _LINUX_REFCOUNT_H */