Both rbd_req_sync_op() and rbd_do_request() have a "linger" parameter, which is the address of a pointer that should refer to the osd request structure used to issue a request to an osd. Only one case ever supplies a non-null "linger" argument: an CEPH_OSD_OP_WATCH start. And in that one case it is assigned &rbd_dev->watch_request. Within rbd_do_request() (where the assignment ultimately gets made) we know the rbd_dev and therefore its watch_request field. We also know whether the op being sent is CEPH_OSD_OP_WATCH start. Stop opaquely passing down the "linger" pointer, and instead just assign the value directly inside rbd_do_request() when it's needed. This makes it unnecessary for rbd_req_sync_watch() to make arrangements to hold a value that's not available until a bit later. This more clearly separates setting up a watch request from submitting it. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>