[PATCH 05/15] rbd: reorder switch statement in rbd_advance_write()

[Hannes Reinecke <hare@xxxxxxx>]

Reorder switch statement to avoid the use of a label/goto
statement and add a 'done' state to indicate that the state
machine has completed.

Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
 drivers/block/rbd.c | 36 +++++++++++++++++++++++++-----------
 1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 4d7857667e9c..766d67e4d5e5 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -267,7 +267,8 @@ enum rbd_obj_read_state {
  * even if there is a parent).
  */
 enum rbd_obj_write_state {
-	RBD_OBJ_WRITE_START = 1,
+	RBD_OBJ_WRITE_DONE,
+	RBD_OBJ_WRITE_START,
 	RBD_OBJ_WRITE_PRE_OBJECT_MAP,
 	RBD_OBJ_WRITE_OBJECT,
 	__RBD_OBJ_WRITE_COPYUP,
@@ -3382,31 +3383,37 @@ static bool rbd_obj_advance_write(struct rbd_obj_request *obj_req, int *result)
 	int ret;
 
 again:
+	dout("%s: obj %p state %d\n", __func__, obj_req, obj_req->write_state);
 	switch (obj_req->write_state) {
 	case RBD_OBJ_WRITE_START:
 		rbd_assert(!*result);
 
-		if (rbd_obj_write_is_noop(obj_req))
+		if (rbd_obj_write_is_noop(obj_req)) {
+			obj_req->write_state = RBD_OBJ_WRITE_DONE;
 			return true;
+		}
 
 		ret = rbd_obj_write_pre_object_map(obj_req);
 		if (ret < 0) {
 			*result = ret;
+			obj_req->write_state = RBD_OBJ_WRITE_DONE;
 			return true;
 		}
 		obj_req->write_state = RBD_OBJ_WRITE_PRE_OBJECT_MAP;
-		if (ret > 0)
-			goto again;
-		return false;
+		if (ret == 0)
+			return false;
+		/* fall through */
 	case RBD_OBJ_WRITE_PRE_OBJECT_MAP:
 		if (*result) {
 			rbd_warn(rbd_dev, "pre object map update failed: %d",
 				 *result);
+			obj_req->write_state = RBD_OBJ_WRITE_DONE;
 			return true;
 		}
 		ret = rbd_obj_write_object(obj_req);
 		if (ret) {
 			*result = ret;
+			obj_req->write_state = RBD_OBJ_WRITE_DONE;
 			return true;
 		}
 		obj_req->write_state = RBD_OBJ_WRITE_OBJECT;
@@ -3426,33 +3433,40 @@ static bool rbd_obj_advance_write(struct rbd_obj_request *obj_req, int *result)
 			if (obj_req->flags & RBD_OBJ_FLAG_DELETION)
 				*result = 0;
 		}
-		if (*result)
+		if (*result) {
+			obj_req->write_state = RBD_OBJ_WRITE_DONE;
 			return true;
-
+		}
 		obj_req->write_state = RBD_OBJ_WRITE_COPYUP;
 		goto again;
 	case __RBD_OBJ_WRITE_COPYUP:
 		if (!rbd_obj_advance_copyup(obj_req, result))
 			return false;
+		obj_req->write_state = RBD_OBJ_WRITE_COPYUP;
 		/* fall through */
 	case RBD_OBJ_WRITE_COPYUP:
 		if (*result) {
 			rbd_warn(rbd_dev, "copyup failed: %d", *result);
+			obj_req->write_state = RBD_OBJ_WRITE_DONE;
 			return true;
 		}
+		obj_req->write_state = RBD_OBJ_WRITE_POST_OBJECT_MAP;
 		ret = rbd_obj_write_post_object_map(obj_req);
 		if (ret < 0) {
 			*result = ret;
+			obj_req->write_state = RBD_OBJ_WRITE_DONE;
 			return true;
 		}
-		obj_req->write_state = RBD_OBJ_WRITE_POST_OBJECT_MAP;
-		if (ret > 0)
-			goto again;
-		return false;
+		if (ret == 0)
+			return false;
+		/* fall through */
 	case RBD_OBJ_WRITE_POST_OBJECT_MAP:
 		if (*result)
 			rbd_warn(rbd_dev, "post object map update failed: %d",
 				 *result);
+		obj_req->write_state = RBD_OBJ_WRITE_DONE;
+		/* fall through */
+	case RBD_OBJ_WRITE_DONE:
 		return true;
 	default:
 		BUG();
-- 
2.16.4