SIMPLEQ_FOREACH_SAFE
SIMPLEQ_FOREACH_SAFE(ccb, &done_list, ccb_entry, ccbtmp) {
SIMPLEQ_FOREACH_SAFE(f, &fd->fd_fbufs_in, fb_next, ftmp) {
SIMPLEQ_FOREACH_SAFE(f, &fd->fd_fbufs_wait, fb_next, ftmp) {