linux-stable/fs/bcachefs/seqmutex.h
Kent Overstreet a5b696ee6e bcachefs: seqmutex; fix a lockdep splat
We can't be holding btree_trans_lock while copying to user space, which
might incur a page fault. To fix this, convert it to a seqmutex so we
can unlock/relock.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:04 -04:00

48 lines
869 B
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _BCACHEFS_SEQMUTEX_H
#define _BCACHEFS_SEQMUTEX_H
#include <linux/mutex.h>
struct seqmutex {
struct mutex lock;
u32 seq;
};
#define seqmutex_init(_lock) mutex_init(&(_lock)->lock)
static inline bool seqmutex_trylock(struct seqmutex *lock)
{
return mutex_trylock(&lock->lock);
}
static inline void seqmutex_lock(struct seqmutex *lock)
{
mutex_lock(&lock->lock);
}
static inline void seqmutex_unlock(struct seqmutex *lock)
{
lock->seq++;
mutex_unlock(&lock->lock);
}
static inline u32 seqmutex_seq(struct seqmutex *lock)
{
return lock->seq;
}
static inline bool seqmutex_relock(struct seqmutex *lock, u32 seq)
{
if (lock->seq != seq || !mutex_trylock(&lock->lock))
return false;
if (lock->seq != seq) {
mutex_unlock(&lock->lock);
return false;
}
return true;
}
#endif /* _BCACHEFS_SEQMUTEX_H */