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-rw-r--r--fs/bcachefs/seqmutex.h48
1 files changed, 48 insertions, 0 deletions
diff --git a/fs/bcachefs/seqmutex.h b/fs/bcachefs/seqmutex.h
new file mode 100644
index 0000000000..c1860d8163
--- /dev/null
+++ b/fs/bcachefs/seqmutex.h
@@ -0,0 +1,48 @@
+/* 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 */