Function drbr_dequeue_cond

freebsd/net/ifq.h:423–446

}

static __inline struct mbuf *
drbr_dequeue_cond(struct ifnet *ifp, struct buf_ring *br,
    int (*func) (struct mbuf *, void *), void *arg) 
{
	struct mbuf *m;
#ifdef ALTQ
	if (ALTQ_IS_ENABLED(&ifp->if_snd)) {
		IFQ_LOCK(&ifp->if_snd);
		IFQ_POLL_NOLOCK(&ifp->if_snd, m);
		if (m != NULL && func(m, arg) == 0) {
			IFQ_UNLOCK(&ifp->if_snd);
			return (NULL);
		}
		IFQ_DEQUEUE_NOLOCK(&ifp->if_snd, m);
		IFQ_UNLOCK(&ifp->if_snd);
		return (m);
	}
#endif
	m = (struct mbuf *)buf_ring_peek(br);
	if (m == NULL || func(m, arg) == 0)
		return (NULL);

	return ((struct mbuf *)buf_ring_dequeue_sc(br));
}

static __inline int
drbr_empty(struct ifnet *ifp, struct buf_ring *br)