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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 17:39:57 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 17:39:57 +0000 |
commit | dc50eab76b709d68175a358d6e23a5a3890764d3 (patch) | |
tree | c754d0390db060af0213ff994f0ac310e4cfd6e9 /fs/bcachefs/two_state_shared_lock.h | |
parent | Adding debian version 6.6.15-2. (diff) | |
download | linux-dc50eab76b709d68175a358d6e23a5a3890764d3.tar.xz linux-dc50eab76b709d68175a358d6e23a5a3890764d3.zip |
Merging upstream version 6.7.7.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/bcachefs/two_state_shared_lock.h')
-rw-r--r-- | fs/bcachefs/two_state_shared_lock.h | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/fs/bcachefs/two_state_shared_lock.h b/fs/bcachefs/two_state_shared_lock.h new file mode 100644 index 0000000000..9058017720 --- /dev/null +++ b/fs/bcachefs/two_state_shared_lock.h @@ -0,0 +1,59 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _BCACHEFS_TWO_STATE_LOCK_H +#define _BCACHEFS_TWO_STATE_LOCK_H + +#include <linux/atomic.h> +#include <linux/sched.h> +#include <linux/wait.h> + +#include "util.h" + +/* + * Two-state lock - can be taken for add or block - both states are shared, + * like read side of rwsem, but conflict with other state: + */ +typedef struct { + atomic_long_t v; + wait_queue_head_t wait; +} two_state_lock_t; + +static inline void two_state_lock_init(two_state_lock_t *lock) +{ + atomic_long_set(&lock->v, 0); + init_waitqueue_head(&lock->wait); +} + +static inline void bch2_two_state_unlock(two_state_lock_t *lock, int s) +{ + long i = s ? 1 : -1; + + EBUG_ON(atomic_long_read(&lock->v) == 0); + + if (atomic_long_sub_return_release(i, &lock->v) == 0) + wake_up_all(&lock->wait); +} + +static inline bool bch2_two_state_trylock(two_state_lock_t *lock, int s) +{ + long i = s ? 1 : -1; + long v = atomic_long_read(&lock->v), old; + + do { + old = v; + + if (i > 0 ? v < 0 : v > 0) + return false; + } while ((v = atomic_long_cmpxchg_acquire(&lock->v, + old, old + i)) != old); + return true; +} + +void __bch2_two_state_lock(two_state_lock_t *, int); + +static inline void bch2_two_state_lock(two_state_lock_t *lock, int s) +{ + if (!bch2_two_state_trylock(lock, s)) + __bch2_two_state_lock(lock, s); +} + +#endif /* _BCACHEFS_TWO_STATE_LOCK_H */ |