| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
|---|---|
| 2 | #ifndef _BCACHEFS_SEQMUTEX_H |
| 3 | #define _BCACHEFS_SEQMUTEX_H |
| 4 | |
| 5 | #include <linux/mutex.h> |
| 6 | |
| 7 | struct seqmutex { |
| 8 | struct mutex lock; |
| 9 | u32 seq; |
| 10 | }; |
| 11 | |
| 12 | #define seqmutex_init(_lock) mutex_init(&(_lock)->lock) |
| 13 | |
| 14 | static inline bool seqmutex_trylock(struct seqmutex *lock) |
| 15 | { |
| 16 | return mutex_trylock(lock: &lock->lock); |
| 17 | } |
| 18 | |
| 19 | static inline void seqmutex_lock(struct seqmutex *lock) |
| 20 | { |
| 21 | mutex_lock(&lock->lock); |
| 22 | } |
| 23 | |
| 24 | static inline void seqmutex_unlock(struct seqmutex *lock) |
| 25 | { |
| 26 | lock->seq++; |
| 27 | mutex_unlock(lock: &lock->lock); |
| 28 | } |
| 29 | |
| 30 | static inline u32 seqmutex_seq(struct seqmutex *lock) |
| 31 | { |
| 32 | return lock->seq; |
| 33 | } |
| 34 | |
| 35 | static inline bool seqmutex_relock(struct seqmutex *lock, u32 seq) |
| 36 | { |
| 37 | if (lock->seq != seq || !mutex_trylock(lock: &lock->lock)) |
| 38 | return false; |
| 39 | |
| 40 | if (lock->seq != seq) { |
| 41 | mutex_unlock(lock: &lock->lock); |
| 42 | return false; |
| 43 | } |
| 44 | |
| 45 | return true; |
| 46 | } |
| 47 | |
| 48 | #endif /* _BCACHEFS_SEQMUTEX_H */ |
| 49 |