projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 0f8f2aaa WL |
1 | #ifndef __LINUX_LOCKREF_H |
| 2 | #define __LINUX_LOCKREF_H | |
| 3 | ||
| 4 | /* | |
| 5 | * Locked reference counts. | |
| 6 | * | |
| 7 | * These are different from just plain atomic refcounts in that they | |
| 8 | * are atomic with respect to the spinlock that goes with them. In | |
| 9 | * particular, there can be implementations that don't actually get | |
| 10 | * the spinlock for the common decrement/increment operations, but they | |
| 11 | * still have to check that the operation is done semantically as if | |
| 12 | * the spinlock had been taken (using a cmpxchg operation that covers | |
| 13 | * both the lock and the count word, or using memory transactions, for | |
| 14 | * example). | |
| 15 | */ | |
| 16 | ||
| 17 | #include <linux/spinlock.h> | |
| 18 | ||
| 19 | struct lockref { | |
| bc08b449 LT |
20 | union { |
| 21 | #ifdef CONFIG_CMPXCHG_LOCKREF | |
| 22 | aligned_u64 lock_count; | |
| 23 | #endif | |
| 24 | struct { | |
| 25 | spinlock_t lock; | |
| 26 | unsigned int count; | |
| 27 | }; | |
| 28 | }; | |
| 0f8f2aaa WL |
29 | }; |
| 30 | ||
| 2f4f12e5 LT |
31 | extern void lockref_get(struct lockref *); |
| 32 | extern int lockref_get_not_zero(struct lockref *); | |
| 33 | extern int lockref_get_or_lock(struct lockref *); | |
| 34 | extern int lockref_put_or_lock(struct lockref *); | |
| 0f8f2aaa | 35 | |
| e7d33bb5 LT |
36 | extern void lockref_mark_dead(struct lockref *); |
| 37 | extern int lockref_get_not_dead(struct lockref *); | |
| 38 | ||
| 0f8f2aaa | 39 | #endif /* __LINUX_LOCKREF_H */ |