static int rx_frames_from_dev(struct mem_link_device *mld,
			      struct mem_ipc_device *dev)
{
	struct link_device *ld = &mld->link_dev;
	struct sk_buff_head *skb_rxq = dev->skb_rxq;
	unsigned int qsize = get_rxq_buff_size(dev);
	unsigned int in = get_rxq_head(dev);
	unsigned int out = get_rxq_tail(dev);
	unsigned int size = circ_get_usage(qsize, in, out);
	int rcvd = 0;

	if (unlikely(circ_empty(in, out)))
		return 0;

	while (rcvd < size) {
		struct sk_buff *skb;
		u8 ch;
		struct io_device *iod;

		skb = rxq_read(mld, dev, in);
		if (!skb)
			break;

		ch = sipc5_get_ch(skb->data);
		iod = link_get_iod_with_channel(ld, ch);
		if (!iod) {
			mif_err("%s: ERR! No IOD for CH.%d\n", ld->name, ch);
			dev_kfree_skb_any(skb);
			mem_forced_cp_crash(mld);
			break;
		}

		/* Record the IO device and the link device into the &skb->cb */
		skbpriv(skb)->iod = iod;
		skbpriv(skb)->ld = ld;

		skbpriv(skb)->lnk_hdr = iod->link_header;
		skbpriv(skb)->sipc_ch = ch;

		/* The $rcvd must be accumulated here, because $skb can be freed
		   in pass_skb_to_demux(). */
		rcvd += skb->len;

		if (likely(sipc_ps_ch(ch)))
			skb_queue_tail(skb_rxq, skb);
		else
			pass_skb_to_demux(mld, skb);
	}

	if (rcvd < size) {
		struct link_device *ld = &mld->link_dev;
		mif_err("%s: WARN! rcvd %d < size %d\n", ld->name, rcvd, size);
	}

	return rcvd;
}
/**
@brief		extract all IPC link frames from a circular queue

In a while loop,\n
1) Receives each IPC link frame stored in the @b @@dev RXQ.\n
2) If the frame is a PS (network) data frame, stores it to an skb_rxq and
   schedules a delayed work for PS data reception.\n
3) Otherwise, passes it to the DEMUX layer immediately.\n

@param mld	the pointer to a mem_link_device instance
@param dev	the pointer to a mem_ipc_device instance (IPC_FMT, etc.)

@retval "> 0"	if valid data received
@retval "= 0"	if no data received
@retval "< 0"	if ANY error
*/
static int rx_frames_from_dev(struct mem_link_device *mld,
			      struct mem_ipc_device *dev)
{
	struct sk_buff_head *skb_rxq = dev->skb_rxq;
	unsigned int qsize = get_rxq_buff_size(dev);
	unsigned int in = get_rxq_head(dev);
	unsigned int out = get_rxq_tail(dev);
	unsigned int size = circ_get_usage(qsize, in, out);
	int rcvd = 0;

	if (unlikely(circ_empty(in, out)))
		return 0;

	while (rcvd < size) {
		struct sk_buff *skb;

		skb = rxq_read(mld, dev, in);
		if (!skb)
			break;

		/* The $rcvd must be accumulated here, because $skb can be freed
		   in pass_skb_to_demux(). */
		rcvd += skb->len;

		if (likely(sipc_ps_ch(sipc5_get_ch_id(skb->data))))
			skb_queue_tail(skb_rxq, skb);
		else
			pass_skb_to_demux(mld, skb);
	}

#ifdef DEBUG_MODEM_IF
	if (rcvd < size) {
		struct link_device *ld = &mld->link_dev;
		mif_err("%s: WARN! rcvd %d < size %d\n", ld->name, rcvd, size);
	}
#endif

	return rcvd;
}