blk-wbt: make enable_state more accurate

[linux-2.6-microblaze.git] / block / blk-wbt.h

diff --git a/block/blk-wbt.h b/block/blk-wbt.h
index 7e44ecc..7fe9863 100644 (file)
--- a/block/blk-wbt.h
+++ b/block/blk-wbt.h
@@ -28,13 +28,15 @@ enum {
 };
 
 /*
- * Enable states. Either off, or on by default (done at init time),
- * or on through manual setup in sysfs.
+ * If current state is WBT_STATE_ON/OFF_DEFAULT, it can be covered to any other
+ * state, if current state is WBT_STATE_ON/OFF_MANUAL, it can only be covered
+ * to WBT_STATE_OFF/ON_MANUAL.
  */
 enum {
-       WBT_STATE_ON_DEFAULT    = 1,
-       WBT_STATE_ON_MANUAL     = 2,
-       WBT_STATE_OFF_DEFAULT
+       WBT_STATE_ON_DEFAULT    = 1,    /* on by default */
+       WBT_STATE_ON_MANUAL     = 2,    /* on manually by sysfs */
+       WBT_STATE_OFF_DEFAULT   = 3,    /* off by default */
+       WBT_STATE_OFF_MANUAL    = 4,    /* off manually by sysfs */
 };
 
 struct rq_wb {