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-rw-r--r--include/linux/lockref.h3
-rw-r--r--lib/lockref.c38
2 files changed, 41 insertions, 0 deletions
diff --git a/include/linux/lockref.h b/include/linux/lockref.h
index ca07b5028b01..f279ed9a9163 100644
--- a/include/linux/lockref.h
+++ b/include/linux/lockref.h
@@ -33,4 +33,7 @@ extern int lockref_get_not_zero(struct lockref *);
extern int lockref_get_or_lock(struct lockref *);
extern int lockref_put_or_lock(struct lockref *);
+extern void lockref_mark_dead(struct lockref *);
+extern int lockref_get_not_dead(struct lockref *);
+
#endif /* __LINUX_LOCKREF_H */
diff --git a/lib/lockref.c b/lib/lockref.c
index 7aae8df37f67..e2cd2c0a8821 100644
--- a/lib/lockref.c
+++ b/lib/lockref.c
@@ -126,3 +126,41 @@ int lockref_put_or_lock(struct lockref *lockref)
return 1;
}
EXPORT_SYMBOL(lockref_put_or_lock);
+
+/**
+ * lockref_mark_dead - mark lockref dead
+ * @lockref: pointer to lockref structure
+ */
+void lockref_mark_dead(struct lockref *lockref)
+{
+ assert_spin_locked(&lockref->lock);
+ lockref->count = -128;
+}
+
+/**
+ * lockref_get_not_dead - Increments count unless the ref is dead
+ * @lockref: pointer to lockref structure
+ * Return: 1 if count updated successfully or 0 if lockref was dead
+ */
+int lockref_get_not_dead(struct lockref *lockref)
+{
+ int retval;
+
+ CMPXCHG_LOOP(
+ new.count++;
+ if ((int)old.count < 0)
+ return 0;
+ ,
+ return 1;
+ );
+
+ spin_lock(&lockref->lock);
+ retval = 0;
+ if ((int) lockref->count >= 0) {
+ lockref->count++;
+ retval = 1;
+ }
+ spin_unlock(&lockref->lock);
+ return retval;
+}
+EXPORT_SYMBOL(lockref_get_not_dead);