SH_LIST_INSERT_HEAD
SH_LIST_INSERT_HEAD(hp, newp, links, __data);
SH_LIST_INSERT_HEAD(hp, newp, links, __data);
SH_LIST_INSERT_HEAD(hp, elp, links, __data);
SH_LIST_INSERT_HEAD(&sh_parent->heldby, lp,
SH_LIST_INSERT_HEAD(&sh_locker->heldby, newl, locker_links, __db_lock);