mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-24 20:54:10 +08:00
19fe87e00b
Standard inlining of fast paths - these locks are now used by our new nocow mode. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
/* 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 */
|