lockref: add ability to mark lockrefs "dead"

[linux-2.6-microblaze.git] / lib / lockref.c

diff --git a/lib/lockref.c b/lib/lockref.c
index 7aae8df..e2cd2c0 100644 (file)
--- 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);