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https://github.com/torvalds/linux
synced 2024-07-21 02:23:16 +00:00
a5b696ee6e
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>
49 lines
869 B
C
49 lines
869 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _BCACHEFS_SEQMUTEX_H
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#define _BCACHEFS_SEQMUTEX_H
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#include <linux/mutex.h>
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struct seqmutex {
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struct mutex lock;
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u32 seq;
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};
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#define seqmutex_init(_lock) mutex_init(&(_lock)->lock)
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static inline bool seqmutex_trylock(struct seqmutex *lock)
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{
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return mutex_trylock(&lock->lock);
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}
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static inline void seqmutex_lock(struct seqmutex *lock)
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{
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mutex_lock(&lock->lock);
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}
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static inline void seqmutex_unlock(struct seqmutex *lock)
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{
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lock->seq++;
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mutex_unlock(&lock->lock);
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}
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static inline u32 seqmutex_seq(struct seqmutex *lock)
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{
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return lock->seq;
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}
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static inline bool seqmutex_relock(struct seqmutex *lock, u32 seq)
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{
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if (lock->seq != seq || !mutex_trylock(&lock->lock))
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return false;
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if (lock->seq != seq) {
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mutex_unlock(&lock->lock);
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return false;
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}
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return true;
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}
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#endif /* _BCACHEFS_SEQMUTEX_H */
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