rq_next
prefetch(rq->rq_next);
*prev = rq->rq_next;
prev = &rq->rq_next;
next = rq->rq_next;
rq->rq_next = NULL;
rq->rq_next = NULL;
rl->tail->rq_next = rq;
rq->rq_next = rl->head;
rq->rq_next = NULL;
for (pos = rq_list_peek((rl)); (pos); pos = pos->rq_next)
for (pos = rq_list_peek((rl)), nxt = pos->rq_next; \
pos; pos = nxt, nxt = pos ? pos->rq_next : NULL)