rbd: drop "object_name" from rbd_req_sync_watch()

rbd_req_sync_watch() is only called in one place, and in that place
it passes rbd_dev->header_name as the value of the "object_name"
parameter.  This value is available within the function already.

Having the extra parameter leaves the impression the object name
could take on different values, but it does not.

So get rid of the parameter.  We can always add it back again if
we find we want to watch some other object in the future.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

drivers/block/rbd.c

@@ -1238,9 +1238,7 @@ static void rbd_watch_cb(u64 ver, u64 notify_id, u8 opcode, void *data)
 /*
  * Request sync osd watch
  */
-static int rbd_req_sync_watch(struct rbd_device *rbd_dev,
-			      const char *object_name,
-			      u64 ver)
+static int rbd_req_sync_watch(struct rbd_device *rbd_dev)
 {
 	struct ceph_osd_req_op *ops;
 	struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
@@ -1254,7 +1252,7 @@ static int rbd_req_sync_watch(struct rbd_device *rbd_dev,
 	if (ret < 0)
 		goto fail;
 
-	ops[0].watch.ver = cpu_to_le64(ver);
+	ops[0].watch.ver = cpu_to_le64(rbd_dev->header.obj_version);
 	ops[0].watch.cookie = cpu_to_le64(rbd_dev->watch_event->cookie);
 	ops[0].watch.flag = 1;
 
@@ -1263,7 +1261,8 @@ static int rbd_req_sync_watch(struct rbd_device *rbd_dev,
 			      0,
 			      CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
 			      ops,
-			      object_name, 0, 0, NULL,
+			      rbd_dev->header_name,
+			      0, 0, NULL,
 			      &rbd_dev->watch_request, NULL);
 
 	if (ret < 0)
@@ -2190,8 +2189,7 @@ static int rbd_init_watch_dev(struct rbd_device *rbd_dev)
 	int ret, rc;
 
 	do {
-		ret = rbd_req_sync_watch(rbd_dev, rbd_dev->header_name,
-					 rbd_dev->header.obj_version);
+		ret = rbd_req_sync_watch(rbd_dev);
 		if (ret == -ERANGE) {
 			mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
 			rc = __rbd_refresh_header(rbd_dev);