q_pkt
pf->tot_bytes_rounded += pad(len) + sizeof(struct q_pkt);
static inline struct q_pkt *
return (struct q_pkt *)(q->buf + ofs);
struct q_pkt *p = pkt_at(q, q->prod_tail);
p->next = q->prod_tail + pad(q->cur_len) + sizeof(struct q_pkt);
need = loops * pf->tot_bytes_rounded + sizeof(struct q_pkt);
struct q_pkt *p = pkt_at(q, q->cons_head);