blob: b10b122dd09989be9bcf70f3700d22ffce0b3623 [file] [log] [blame]
* 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>
#include <generated/bounds.h>
struct lockref {
union {
aligned_u64 lock_count;
struct {
spinlock_t lock;
int count;
extern void lockref_get(struct lockref *);
extern int lockref_put_return(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 */