+/**
+ * key_invalidate - Invalidate a key.
+ * @key: The key to be invalidated.
+ *
+ * Mark a key as being invalidated and have it cleaned up immediately. The key
+ * is ignored by all searches and other operations from this point.
+ */
+void key_invalidate(struct key *key)
+{
+ kenter("%d", key_serial(key));
+
+ key_check(key);
+
+ if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
+ down_write_nested(&key->sem, 1);
+ if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags))
+ key_schedule_gc_links();
+ up_write(&key->sem);
+ }
+}
+EXPORT_SYMBOL(key_invalidate);
+