C++ dev_kfree_skb函数代码示例

/*
 * The typical workload of the driver:
 *   Handle the network interface interrupts.
 */
static void
net_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
	struct net_device *dev;
	struct net_local *lp;
	int status = 0;

	BUGMSG("net_interrupt..");
	if (dev_id == NULL) {
		printk(KERN_WARNING "%s: irq %d for unknown device.\n", cardname, irq);
		return;
	}

	dev = (struct net_device *) dev_id;
	lp = (struct net_local *) dev->priv;

	status = lp->uEth->INTST;

	/* RX Start: No frame available during frame RX */
	if(status & ETHINTSTRXSTART) {
		printk("PANIC: Ethernet RX Queue is empty: this should NEVER Occur!!!\n");
		printk("rxq_ptr = %d\n", lp->rxq_ptr);
	}

	/* RX End: a frame is received successfully */
	if(status & ETHINTSTRXEND) {
		BUGMSG("RX end..");
		do {
			unsigned int rx_packet_stat = lp->uEth->RXSTAT;

			if(rx_packet_stat & ETHRXSTATERROR) {
				printk("RX Packet error 0x%.8x\n", rx_packet_stat);
				lp->stats.rx_dropped++;
				/* We reuse the frame */
				lp->uEth->RXADDR = (int)lp->rx_frames[lp->rxq_ptr & (ETH_RXQ_SIZE -1)];
			} else {
				unsigned int length = (rx_packet_stat & 0x3fff);
				struct sk_buff *skb;
				struct sk_buff *newskb;

				BUGMSG("rxq %d, skblen %d..", lp->rxq_ptr, length);
				/* The received skb */
				skb = lp->rx_frames[lp->rxq_ptr & (ETH_RXQ_SIZE -1)];
				skb_put(skb, length);
				lp->stats.rx_packets++;
				lp->stats.rx_bytes += length;

				/* Alloc new skb for rx_frame ringbuffer */
				newskb = dev_alloc_skb( PKT_BUF_SZ );
				if (newskb == NULL) {
					/* We assume that we can consume and produce the RX ring
					 * buffer at the same time. In this case, we cannot
					 * produce so we will eventually crash ...
					 */
					printk("Cannot allocate skb. This is very bad.... We will CRASH!\n");
				} else {
					newskb->dev = dev;
					newskb->protocol = eth_type_trans(skb, dev);
					newskb->ip_summed = CHECKSUM_UNNECESSARY; /* don't check it */
					/* word align IP header */
					skb_reserve( newskb, 2 );
					lp->rx_frames[lp->rxq_ptr & (ETH_RXQ_SIZE -1)] = newskb;
					/* Put in Ethernet RX queue */
					lp->uEth->RXADDR = (int) newskb->data;
				}
				lp->rxq_ptr++;
				netif_rx(skb);
			}
		} while(lp->uEth->INTST & ETHINTSTRXEND);
	}

	if(status & ETHINTSTTXEND) {
		BUGMSG("TX end..");
		do {
			unsigned int tx_packet_stat = lp->uEth->TXSTAT;
			struct sk_buff *skb;

			BUGMSG("*%d %d", lp->txq_p, lp->txq_c);
			if(tx_packet_stat)
				printk("TX Packet error 0x%.8x\n", tx_packet_stat);

			skb = lp->tx_frames[lp->txq_c & (ETH_TXQ_SIZE -1)];
			/* paranoia check should be removed */
			if(skb == NULL) {
				printk("ERROR: tx frame NULL\n");
				break;
			}
			lp->tx_frames[lp->txq_c & (ETH_TXQ_SIZE -1)] = NULL;
			lp->txq_c++;
			lp->stats.tx_packets++;
			dev_kfree_skb(skb);
		} while(lp->uEth->INTST & ETHINTSTTXEND);
	}
	BUGMSG("\n");
	return;
}

/* Put the CAIF packet on the virtio ring and kick the receiver */
static int cfv_netdev_tx(struct sk_buff *skb, struct net_device *netdev)
{
	struct cfv_info *cfv = netdev_priv(netdev);
	struct buf_info *buf_info;
	struct scatterlist sg;
	unsigned long flags;
	bool flow_off = false;
	int ret;

	/* garbage collect released buffers */
	cfv_release_used_buf(cfv->vq_tx);
	spin_lock_irqsave(&cfv->tx_lock, flags);

	/* Flow-off check takes into account number of cpus to make sure
	 * virtqueue will not be overfilled in any possible smp conditions.
	 *
	 * Flow-on is triggered when sufficient buffers are freed
	 */
	if (unlikely(cfv->vq_tx->num_free <= num_present_cpus())) {
		flow_off = true;
		cfv->stats.tx_full_ring++;
	}

	/* If we run out of memory, we release the memory reserve and retry
	 * allocation.
	 */
	buf_info = cfv_alloc_and_copy_to_shm(cfv, skb, &sg);
	if (unlikely(!buf_info)) {
		cfv->stats.tx_no_mem++;
		flow_off = true;

		if (cfv->reserved_mem && cfv->genpool) {
			gen_pool_free(cfv->genpool,  cfv->reserved_mem,
				      cfv->reserved_size);
			cfv->reserved_mem = 0;
			buf_info = cfv_alloc_and_copy_to_shm(cfv, skb, &sg);
		}
	}

	if (unlikely(flow_off)) {
		/* Turn flow on when a 1/4 of the descriptors are released */
		cfv->watermark_tx = virtqueue_get_vring_size(cfv->vq_tx) / 4;
		/* Enable notifications of recycled TX buffers */
		virtqueue_enable_cb(cfv->vq_tx);
		netif_tx_stop_all_queues(netdev);
	}

	if (unlikely(!buf_info)) {
		/* If the memory reserve does it's job, this shouldn't happen */
		netdev_warn(cfv->ndev, "Out of gen_pool memory\n");
		goto err;
	}

	ret = virtqueue_add_outbuf(cfv->vq_tx, &sg, 1, buf_info, GFP_ATOMIC);
	if (unlikely((ret < 0))) {
		/* If flow control works, this shouldn't happen */
		netdev_warn(cfv->ndev, "Failed adding buffer to TX vring:%d\n",
			    ret);
		goto err;
	}

	/* update netdev statistics */
	cfv->ndev->stats.tx_packets++;
	cfv->ndev->stats.tx_bytes += skb->len;
	spin_unlock_irqrestore(&cfv->tx_lock, flags);

	/* tell the remote processor it has a pending message to read */
	virtqueue_kick(cfv->vq_tx);

	dev_kfree_skb(skb);
	return NETDEV_TX_OK;
err:
	spin_unlock_irqrestore(&cfv->tx_lock, flags);
	cfv->ndev->stats.tx_dropped++;
	free_buf_info(cfv, buf_info);
	dev_kfree_skb(skb);
	return NETDEV_TX_OK;
}

static ssize_t eemcs_ipc_write(struct file *fp, const char __user *buf, size_t in_sz, loff_t *ppos)
{
    ssize_t ret   = 0;
    eemcs_ipc_node_t *curr_node = (eemcs_ipc_node_t *)fp->private_data;
    KAL_UINT8 node_id = curr_node->ipc_node_id;/* node_id */
    KAL_UINT8 port_id = eemcs_ipc_inst.eemcs_port_id; /* port_id */
    KAL_UINT32 p_type, control_flag;    
    struct sk_buff *new_skb;
    CCCI_BUFF_T *ccci_header;
    ipc_ilm_t *ilm=NULL;
    IPC_MSGSVC_TASKMAP_T *id_map;
    size_t count = in_sz;
    size_t skb_alloc_size;
    KAL_UINT32 alloc_time = 0, curr_time = 0;
    
    DEBUG_LOG_FUNCTION_ENTRY;        
    DBGLOG(IPCD, DBG, "[TX]deivce=%s iminor=%d len=%d", curr_node->dev_name, node_id, count);

    p_type = ccci_get_port_type(port_id);
    if(p_type != EX_T_USER) 
    {
        DBGLOG(IPCD, ERR, "PORT%d refuse port(%d) access user port", port_id, p_type);
        ret=-EINVAL;
        goto _exit;                    
    }

    control_flag = ccci_get_port_cflag(port_id);	
    if (check_device_state() == EEMCS_EXCEPTION) {//modem exception		
        if ((control_flag & TX_PRVLG2) == 0) {
            DBGLOG(IPCD, TRA, "[TX]PORT%d write fail when modem exception", port_id);
            return -ETXTBSY;
        }
    } else if (check_device_state() != EEMCS_BOOTING_DONE) {//modem not ready
        if ((control_flag & TX_PRVLG1) == 0) {
            DBGLOG(IPCD, TRA, "[TX]PORT%d write fail when modem not ready", port_id);
            return -ENODEV;
        }
    }

    if((control_flag & EXPORT_CCCI_H) && (count < sizeof(CCCI_BUFF_T)))
    {
        DBGLOG(IPCD, ERR, "invalid wirte_len(%d) of PORT%d", count, port_id);
        ret=-EINVAL;
        goto _exit;            
    }

    if(control_flag & EXPORT_CCCI_H){
        if(count > (MAX_TX_BYTE+sizeof(CCCI_BUFF_T))){
            DBGLOG(IPCD, WAR, "PORT%d wirte_len(%d)>MTU(%d)!", port_id, count, MAX_TX_BYTE);
            count = MAX_TX_BYTE+sizeof(CCCI_BUFF_T);
        }
        skb_alloc_size = count - sizeof(CCCI_BUFF_T);
    }else{
        if(count > MAX_TX_BYTE){
            DBGLOG(IPCD, WAR, "PORT%d wirte_len(%d)>MTU(%d)!", port_id, count, MAX_TX_BYTE);
            count = MAX_TX_BYTE;
        }
        skb_alloc_size = count;
    }

    if (ccci_ch_write_space_alloc(eemcs_ipc_inst.ccci_ch.tx)==0){
        DBGLOG(IPCD, WAR, "PORT%d write return 0)", port_id);
        ret = -EAGAIN;
        goto _exit;
    }	
    
    new_skb = ccci_ipc_mem_alloc(skb_alloc_size + CCCI_IPC_HEADER_ROOM, GFP_ATOMIC);
    if(NULL == new_skb)
    {
    	DBGLOG(CHAR, INF, "[TX]PORT%d alloc skb fail with wait", port_id);
    	alloc_time = jiffies;
    	new_skb = ccci_ipc_mem_alloc(skb_alloc_size + CCCI_IPC_HEADER_ROOM, GFP_KERNEL);
    	if (NULL == new_skb) {
            ret = -ENOMEM;
            DBGLOG(IPCD, ERR, "[TX]PORT%d alloc skb fail with wait fail", port_id);
            goto _exit; 
    	}

    	curr_time = jiffies;
    	if ((curr_time - alloc_time) >= 1) {			
            DBGLOG(IPCD, ERR, "[TX]PORT%d alloc skb delay: time=%dms", port_id, \
			10*(curr_time - alloc_time));
    	}
    }
    
    /* reserve SDIO_H header room */
    #ifdef CCCI_SDIO_HEAD
    skb_reserve(new_skb, sizeof(SDIO_H));
    #endif

    ccci_header = (CCCI_BUFF_T *)skb_put(new_skb, sizeof(CCCI_BUFF_T)) ;

    if(copy_from_user(skb_put(new_skb, count), buf, count))
    {
        DBGLOG(IPCD, ERR, "[TX]PORT%d copy_from_user(len=%d, %p->%p) fail", \
		port_id, count, buf, new_skb->data);
        dev_kfree_skb(new_skb);
        ret = -EFAULT;
        goto _exit;
    }
//.........这里部分代码省略.........

static int ni52_send_packet(struct sk_buff *skb, struct net_device *dev)
{
	int len, i;
#ifndef NO_NOPCOMMANDS
	int next_nop;
#endif
	struct priv *p = netdev_priv(dev);

	if (skb->len > XMIT_BUFF_SIZE) {
		printk(KERN_ERR "%s: Sorry, max. framelength is %d bytes. The length of your frame is %d bytes.\n", dev->name, XMIT_BUFF_SIZE, skb->len);
		return 0;
	}

	netif_stop_queue(dev);

	memcpy_toio(p->xmit_cbuffs[p->xmit_count], skb->data, skb->len);
	len = skb->len;
	if (len < ETH_ZLEN) {
		len = ETH_ZLEN;
		memset_io(p->xmit_cbuffs[p->xmit_count]+skb->len, 0,
							len - skb->len);
	}

#if (NUM_XMIT_BUFFS == 1)
#	ifdef NO_NOPCOMMANDS

#ifdef DEBUG
	if (readb(&p->scb->cus) & CU_ACTIVE) {
		printk(KERN_ERR "%s: Hmmm .. CU is still running and we wanna send a new packet.\n", dev->name);
		printk(KERN_ERR "%s: stat: %04x %04x\n",
				dev->name, readb(&p->scb->cus),
				readw(&p->xmit_cmds[0]->cmd_status));
	}
#endif
	writew(TBD_LAST | len, &p->xmit_buffs[0]->size);
	for (i = 0; i < 16; i++) {
		writew(0, &p->xmit_cmds[0]->cmd_status);
		wait_for_scb_cmd(dev);
		if ((readb(&p->scb->cus) & CU_STATUS) == CU_SUSPEND)
			writeb(CUC_RESUME, &p->scb->cmd_cuc);
		else {
			writew(make16(p->xmit_cmds[0]), &p->scb->cbl_offset);
			writeb(CUC_START, &p->scb->cmd_cuc);
		}
		ni_attn586();
		dev->trans_start = jiffies;
		if (!i)
			dev_kfree_skb(skb);
		wait_for_scb_cmd(dev);
		/* test it, because CU sometimes doesn't start immediately */
		if (readb(&p->scb->cus) & CU_ACTIVE)
			break;
		if (readw(&p->xmit_cmds[0]->cmd_status))
			break;
		if (i == 15)
			printk(KERN_WARNING "%s: Can't start transmit-command.\n", dev->name);
	}
#	else
	next_nop = (p->nop_point + 1) & 0x1;
	writew(TBD_LAST | len, &p->xmit_buffs[0]->size);
	writew(make16(p->nop_cmds[next_nop]), &p->xmit_cmds[0]->cmd_link);
	writew(make16(p->nop_cmds[next_nop]),
				&p->nop_cmds[next_nop]->cmd_link);
	writew(0, &p->xmit_cmds[0]->cmd_status);
	writew(0, &p->nop_cmds[next_nop]->cmd_status);

	writew(make16(p->xmit_cmds[0]), &p->nop_cmds[p->nop_point]->cmd_link);
	dev->trans_start = jiffies;
	p->nop_point = next_nop;
	dev_kfree_skb(skb);
#	endif
#else
	writew(TBD_LAST | len, &p->xmit_buffs[p->xmit_count]->size);
	next_nop = p->xmit_count + 1
	if (next_nop == NUM_XMIT_BUFFS)
		next_nop = 0;
	writew(0, &p->xmit_cmds[p->xmit_count]->cmd_status);
	/* linkpointer of xmit-command already points to next nop cmd */
	writew(make16(p->nop_cmds[next_nop]),
				&p->nop_cmds[next_nop]->cmd_link);
	writew(0, &p->nop_cmds[next_nop]->cmd_status);
	writew(make16(p->xmit_cmds[p->xmit_count]),
				&p->nop_cmds[p->xmit_count]->cmd_link);
	dev->trans_start = jiffies;
	p->xmit_count = next_nop;
	{
		unsigned long flags;
		spin_lock_irqsave(&p->spinlock);
		if (p->xmit_count != p->xmit_last)
			netif_wake_queue(dev);
		spin_unlock_irqrestore(&p->spinlock);
	}
	dev_kfree_skb(skb);
#endif
	return 0;
}

static void receive_skb(struct net_device *dev, struct sk_buff *skb,
			unsigned len)
{
	struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);

	if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
		pr_debug("%s: short packet %i\n", dev->name, len);
		dev->stats.rx_length_errors++;
		goto drop;
	}
	len -= sizeof(struct virtio_net_hdr);
	BUG_ON(len > MAX_PACKET_LEN);

	skb_trim(skb, len);
	skb->protocol = eth_type_trans(skb, dev);
	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
		 ntohs(skb->protocol), skb->len, skb->pkt_type);
	dev->stats.rx_bytes += skb->len;
	dev->stats.rx_packets++;

	if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
		pr_debug("Needs csum!\n");
		skb->ip_summed = CHECKSUM_PARTIAL;
		skb->csum_start = hdr->csum_start;
		skb->csum_offset = hdr->csum_offset;
		if (skb->csum_start > skb->len - 2
		    || skb->csum_offset > skb->len - 2) {
			if (net_ratelimit())
				printk(KERN_WARNING "%s: csum=%u/%u len=%u\n",
				       dev->name, skb->csum_start,
				       skb->csum_offset, skb->len);
			goto frame_err;
		}
	}

	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
		pr_debug("GSO!\n");
		switch (hdr->gso_type) {
		case VIRTIO_NET_HDR_GSO_TCPV4:
			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
			break;
		case VIRTIO_NET_HDR_GSO_TCPV4_ECN:
			skb_shinfo(skb)->gso_type = SKB_GSO_TCP_ECN;
			break;
		case VIRTIO_NET_HDR_GSO_UDP:
			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
			break;
		case VIRTIO_NET_HDR_GSO_TCPV6:
			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
			break;
		default:
			if (net_ratelimit())
				printk(KERN_WARNING "%s: bad gso type %u.\n",
				       dev->name, hdr->gso_type);
			goto frame_err;
		}

		skb_shinfo(skb)->gso_size = hdr->gso_size;
		if (skb_shinfo(skb)->gso_size == 0) {
			if (net_ratelimit())
				printk(KERN_WARNING "%s: zero gso size.\n",
				       dev->name);
			goto frame_err;
		}

		/* Header must be checked, and gso_segs computed. */
		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
		skb_shinfo(skb)->gso_segs = 0;
	}

	netif_receive_skb(skb);
	return;

frame_err:
	dev->stats.rx_frame_errors++;
drop:
	dev_kfree_skb(skb);
}

static void
bch_l2l1(struct hisax_if *ifc, int pr, void *arg)
{
	struct hfc4s8s_btype *bch = ifc->priv;
	struct hfc4s8s_l1 *l1 = bch->l1p;
	struct sk_buff *skb = (struct sk_buff *) arg;
	long mode = (long) arg;
	u_long flags;

	switch (pr) {

		case (PH_DATA | REQUEST):
			if (!l1->enabled || (bch->mode == L1_MODE_NULL)) {
				dev_kfree_skb(skb);
				break;
			}
			spin_lock_irqsave(&l1->lock, flags);
			skb_queue_tail(&bch->tx_queue, skb);
			if (!bch->tx_skb && (bch->tx_cnt <= 0)) {
				l1->hw->mr.r_irq_fifo_blx[l1->st_num] |=
				    ((bch->bchan == 1) ? 1 : 4);
				spin_unlock_irqrestore(&l1->lock, flags);
				schedule_work(&l1->hw->tqueue);
			} else
				spin_unlock_irqrestore(&l1->lock, flags);
			break;

		case (PH_ACTIVATE | REQUEST):
		case (PH_DEACTIVATE | REQUEST):
			if (!l1->enabled)
				break;
			if (pr == (PH_DEACTIVATE | REQUEST))
				mode = L1_MODE_NULL;

			switch (mode) {
				case L1_MODE_HDLC:
					spin_lock_irqsave(&l1->lock,
							  flags);
					l1->hw->mr.timer_usg_cnt++;
					l1->hw->mr.
					    fifo_slow_timer_service[l1->
								    st_num]
					    |=
					    ((bch->bchan ==
					      1) ? 0x2 : 0x8);
					Write_hfc8(l1->hw, R_FIFO,
						   (l1->st_num * 8 +
						    ((bch->bchan ==
						      1) ? 0 : 2)));
					wait_busy(l1->hw);
					Write_hfc8(l1->hw, A_CON_HDLC, 0xc);	/* HDLC mode, flag fill, connect ST */
					Write_hfc8(l1->hw, A_SUBCH_CFG, 0);	/* 8 bits */
					Write_hfc8(l1->hw, A_IRQ_MSK, 1);	/* enable TX interrupts for hdlc */
					Write_hfc8(l1->hw, A_INC_RES_FIFO, 2);	/* reset fifo */
					wait_busy(l1->hw);

					Write_hfc8(l1->hw, R_FIFO,
						   (l1->st_num * 8 +
						    ((bch->bchan ==
						      1) ? 1 : 3)));
					wait_busy(l1->hw);
					Write_hfc8(l1->hw, A_CON_HDLC, 0xc);	/* HDLC mode, flag fill, connect ST */
					Write_hfc8(l1->hw, A_SUBCH_CFG, 0);	/* 8 bits */
					Write_hfc8(l1->hw, A_IRQ_MSK, 1);	/* enable RX interrupts for hdlc */
					Write_hfc8(l1->hw, A_INC_RES_FIFO, 2);	/* reset fifo */

					Write_hfc8(l1->hw, R_ST_SEL,
						   l1->st_num);
					l1->hw->mr.r_ctrl0 |=
					    (bch->bchan & 3);
					Write_hfc8(l1->hw, A_ST_CTRL0,
						   l1->hw->mr.r_ctrl0);
					bch->mode = L1_MODE_HDLC;
					spin_unlock_irqrestore(&l1->lock,
							       flags);

					bch->b_if.ifc.l1l2(&bch->b_if.ifc,
							   PH_ACTIVATE |
							   INDICATION,
							   NULL);
					break;

				case L1_MODE_TRANS:
					spin_lock_irqsave(&l1->lock,
							  flags);
					l1->hw->mr.
					    fifo_rx_trans_enables[l1->
								  st_num]
					    |=
					    ((bch->bchan ==
					      1) ? 0x2 : 0x8);
					l1->hw->mr.timer_usg_cnt++;
					Write_hfc8(l1->hw, R_FIFO,
						   (l1->st_num * 8 +
						    ((bch->bchan ==
						      1) ? 0 : 2)));
					wait_busy(l1->hw);
					Write_hfc8(l1->hw, A_CON_HDLC, 0xf);	/* Transparent mode, 1 fill, connect ST */
					Write_hfc8(l1->hw, A_SUBCH_CFG, 0);	/* 8 bits */
					Write_hfc8(l1->hw, A_IRQ_MSK, 0);	/* disable TX interrupts */
//.........这里部分代码省略.........

static void
rx_d_frame(struct hfc4s8s_l1 *l1p, int ech)
{
	int z1, z2;
	u_char f1, f2, df;
	struct sk_buff *skb;
	u_char *cp;


	if (!l1p->enabled)
		return;
	do {
		/* E/D RX fifo */
		Write_hfc8(l1p->hw, R_FIFO,
			   (l1p->st_num * 8 + ((ech) ? 7 : 5)));
		wait_busy(l1p->hw);

		f1 = Read_hfc8_stable(l1p->hw, A_F1);
		f2 = Read_hfc8(l1p->hw, A_F2);
		df = f1 - f2;
		if ((f1 - f2) < 0)
			df = f1 - f2 + MAX_F_CNT + 1;


		if (!df) {
			return;	/* no complete frame in fifo */
		}

		z1 = Read_hfc16_stable(l1p->hw, A_Z1);
		z2 = Read_hfc16(l1p->hw, A_Z2);

		z1 = z1 - z2 + 1;
		if (z1 < 0)
			z1 += 384;

		if (!(skb = dev_alloc_skb(MAX_D_FRAME_SIZE))) {
			printk(KERN_INFO
			       "HFC-4S/8S: Could not allocate D/E "
			       "channel receive buffer");
			Write_hfc8(l1p->hw, A_INC_RES_FIFO, 2);
			wait_busy(l1p->hw);
			return;
		}

		if (((z1 < 4) || (z1 > MAX_D_FRAME_SIZE))) {
			if (skb)
				dev_kfree_skb(skb);
			/* remove errornous D frame */
			if (df == 1) {
				/* reset fifo */
				Write_hfc8(l1p->hw, A_INC_RES_FIFO, 2);
				wait_busy(l1p->hw);
				return;
			} else {
				/* read errornous D frame */

#ifndef HISAX_HFC4S8S_PCIMEM
				SetRegAddr(l1p->hw, A_FIFO_DATA0);
#endif

				while (z1 >= 4) {
#ifdef HISAX_HFC4S8S_PCIMEM
					Read_hfc32(l1p->hw, A_FIFO_DATA0);
#else
					fRead_hfc32(l1p->hw);
#endif
					z1 -= 4;
				}

				while (z1--)
#ifdef HISAX_HFC4S8S_PCIMEM
					Read_hfc8(l1p->hw, A_FIFO_DATA0);
#else
					fRead_hfc8(l1p->hw);
#endif

				Write_hfc8(l1p->hw, A_INC_RES_FIFO, 1);
				wait_busy(l1p->hw);
				return;
			}
		}

		cp = skb->data;

#ifndef HISAX_HFC4S8S_PCIMEM
		SetRegAddr(l1p->hw, A_FIFO_DATA0);
#endif

		while (z1 >= 4) {
#ifdef HISAX_HFC4S8S_PCIMEM
			*((unsigned long *) cp) =
			    Read_hfc32(l1p->hw, A_FIFO_DATA0);
#else
			*((unsigned long *) cp) = fRead_hfc32(l1p->hw);
#endif
			cp += 4;
			z1 -= 4;
		}

		while (z1--)
//.........这里部分代码省略.........

//.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- Dta1xxNwStartXmit -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
//
// The stack will execute Dta1xxNwStartXmit only ones.
// (NETIF_F_LLTX flag is not set)
//
int Dta1xxNwStartXmit(struct sk_buff* pSkb, struct net_device* pDevice)
{	
	Dta1xxNw_Private* lp = (Dta1xxNw_Private*)netdev_priv(pDevice);
	Dta1xxDmaTxHeader* pTxHeader;
	Int PktLength;
	Int TotalLength;
	UInt FreeSpaceUntilEnd;
	UInt FreeSpaceFromBegin;
	UInt ReadOffset;
	UInt WriteOffset;
	Dta1xxNwBuf* pNwTx = &lp->m_NwTxBuf;

#if LOG_LEVEL > 0
	DTA1XXNW_LOG(KERN_DEBUG, "Dta1xxNwStartXmit is called");
#endif
	
	// Check if it's our own dummy generated packet
	if ((pSkb->len >= (sizeof(EthernetIIHeader) + sizeof(IpHeaderV4)-5 + sizeof(UdpHeader) + 10)) &&
	    (pSkb->len <= ETH_ZLEN)){
		EthernetIIHeader* pEthernetIIHeader;
		IpHeaderV4* pIpHeader;
		UdpHeader* pUdpHeader;
		UInt8* pData;
	
		pEthernetIIHeader = (EthernetIIHeader*)pSkb->data;
		pIpHeader = (IpHeaderV4*)(pSkb->data + sizeof(EthernetIIHeader));
		pUdpHeader = (UdpHeader*)(pSkb->data + sizeof(EthernetIIHeader)+ sizeof(IpHeaderV4)-5);
		pData = pSkb->data + sizeof(EthernetIIHeader) + sizeof(IpHeaderV4)-5 + sizeof(UdpHeader);
		if ((pUdpHeader->m_DestinationPort ==  0x0400) && 
			(strcmp(pData, "DektecArp\0") == 0)) {
			// It's our own dummy packet. Skip it.
			dev_kfree_skb(pSkb);
			return STATUS_SUCCESS;
		} 
	}

	if (lp->m_Connected == 0) {
		lp->m_NetStats.tx_errors++;
		return STATUS_UNSUCCESSFUL;
	}
	PktLength = (pSkb->len < ETH_ZLEN ? ETH_ZLEN : pSkb->len);
    
	// Make sure there is enough free space for a complete packet including header and alignment
	TotalLength = PktLength + sizeof(Dta1xxDmaTxHeader);
	if ((TotalLength%4)!=0)
		TotalLength += (4-(TotalLength%4));
	
	ReadOffset = pNwTx->m_ReadOffset;
	WriteOffset = pNwTx->m_WriteOffset;
	if (WriteOffset < ReadOffset) {
		FreeSpaceFromBegin = 0;
		FreeSpaceUntilEnd = ReadOffset - WriteOffset - 1;
	} else {
		FreeSpaceUntilEnd = pNwTx->m_BufSize - WriteOffset - 1;
		if (ReadOffset == 0)
			FreeSpaceFromBegin = 0;
		else
			FreeSpaceFromBegin = ReadOffset - 1;
	}

	if (FreeSpaceUntilEnd >= TotalLength) {
		// Found free space at end of buffer
		pTxHeader = (Dta1xxDmaTxHeader*)(pNwTx->m_pBuffer + WriteOffset);

	} else if (FreeSpaceFromBegin >= TotalLength) {
		// Found free space at begin of buffer
		// Mark first free byte at end of buffer as not used '*',
		// so the TxThread knows to start next packet at begin of buffer.
		pNwTx->m_pBuffer[WriteOffset] = '*';
		WriteOffset = 0;
		pTxHeader = (Dta1xxDmaTxHeader*)(pNwTx->m_pBuffer + WriteOffset);
	} else {
		// Not enough free space, skip pakket
		lp->m_NetStats.tx_dropped++;
		return STATUS_UNSUCCESSFUL;
	}

	memset(pTxHeader, 0, sizeof(Dta1xxDmaTxHeader));

	pTxHeader->Tag = 0x445441A0;
	pTxHeader->Version = 1;
	pTxHeader->Length = sizeof(Dta1xxDmaTxHeader);
	pTxHeader->TransmitControl.PacketLength = PktLength;
	WriteOffset+= sizeof(Dta1xxDmaTxHeader);
	
	if (pSkb->len < ETH_ZLEN) {
		// Reset stuffing bytes
		memset(pNwTx->m_pBuffer+WriteOffset, 0, ETH_ZLEN);
	}
	memcpy(pNwTx->m_pBuffer+WriteOffset, pSkb->data, pSkb->len);

	// Make sure the next packet is aligned on multiples of 4
	if ((PktLength%4)!=0)
		PktLength += (4-(PktLength%4));

//.........这里部分代码省略.........

static void
dch_l2l1(struct hisax_d_if *iface, int pr, void *arg)
{
	struct hfc4s8s_l1 *l1 = iface->ifc.priv;
	struct sk_buff *skb = (struct sk_buff *) arg;
	u_long flags;

	switch (pr) {

		case (PH_DATA | REQUEST):
			if (!l1->enabled) {
				dev_kfree_skb(skb);
				break;
			}
			spin_lock_irqsave(&l1->lock, flags);
			skb_queue_tail(&l1->d_tx_queue, skb);
			if ((skb_queue_len(&l1->d_tx_queue) == 1) &&
			    (l1->tx_cnt <= 0)) {
				l1->hw->mr.r_irq_fifo_blx[l1->st_num] |=
				    0x10;
				spin_unlock_irqrestore(&l1->lock, flags);
				schedule_work(&l1->hw->tqueue);
			} else
				spin_unlock_irqrestore(&l1->lock, flags);
			break;

		case (PH_ACTIVATE | REQUEST):
			if (!l1->enabled)
				break;
			if (!l1->nt_mode) {
				if (l1->l1_state < 6) {
					spin_lock_irqsave(&l1->lock,
							  flags);

					Write_hfc8(l1->hw, R_ST_SEL,
						   l1->st_num);
					Write_hfc8(l1->hw, A_ST_WR_STA,
						   0x60);
					mod_timer(&l1->l1_timer,
						  jiffies + L1_TIMER_T3);
					spin_unlock_irqrestore(&l1->lock,
							       flags);
				} else if (l1->l1_state == 7)
					l1->d_if.ifc.l1l2(&l1->d_if.ifc,
							  PH_ACTIVATE |
							  INDICATION,
							  NULL);
			} else {
				if (l1->l1_state != 3) {
					spin_lock_irqsave(&l1->lock,
							  flags);
					Write_hfc8(l1->hw, R_ST_SEL,
						   l1->st_num);
					Write_hfc8(l1->hw, A_ST_WR_STA,
						   0x60);
					spin_unlock_irqrestore(&l1->lock,
							       flags);
				} else if (l1->l1_state == 3)
					l1->d_if.ifc.l1l2(&l1->d_if.ifc,
							  PH_ACTIVATE |
							  INDICATION,
							  NULL);
			}
			break;

		default:
			printk(KERN_INFO
			       "HFC-4S/8S: Unknown D-chan cmd 0x%x received, ignored\n",
			       pr);
			break;
	}
	if (!l1->enabled)
		l1->d_if.ifc.l1l2(&l1->d_if.ifc,
				  PH_DEACTIVATE | INDICATION, NULL);
}				/* dch_l2l1 */

static int ibmlana_tx(struct sk_buff *skb, struct net_device *dev)
{
	ibmlana_priv *priv = netdev_priv(dev);
	int retval = 0, tmplen, addr;
	unsigned long flags;
	tda_t tda;
	int baddr;

	/* find out if there are free slots for a frame to transmit. If not,
	   the upper layer is in deep desperation and we simply ignore the frame. */

	if (priv->txusedcnt >= TXBUFCNT) {
		retval = -EIO;
		priv->stat.tx_dropped++;
		goto tx_done;
	}

	/* copy the frame data into the next free transmit buffer - fillup missing */
	tmplen = skb->len;
	if (tmplen < 60)
		tmplen = 60;
	baddr = priv->txbufstart + (priv->nexttxdescr * PKTSIZE);
	memcpy_toio(priv->base + baddr, skb->data, skb->len);

	/* copy filler into RAM - in case we're filling up... 
	   we're filling a bit more than necessary, but that doesn't harm
	   since the buffer is far larger... 
	   Sorry Linus for the filler string but I couldn't resist ;-) */

	if (tmplen > skb->len) {
		char *fill = "NetBSD is a nice OS too! ";
		unsigned int destoffs = skb->len, l = strlen(fill);

		while (destoffs < tmplen) {
			memcpy_toio(priv->base + baddr + destoffs, fill, l);
			destoffs += l;
		}
	}

	/* set up the new frame descriptor */
	addr = priv->tdastart + (priv->nexttxdescr * sizeof(tda_t));
	memcpy_fromio(&tda, priv->base + addr, sizeof(tda_t));
	tda.length = tda.fraglength = tmplen;
	memcpy_toio(priv->base + addr, &tda, sizeof(tda_t));

	/* if there were no active descriptors, trigger the SONIC */
	spin_lock_irqsave(&priv->lock, flags);

	priv->txusedcnt++;
	priv->txused[priv->nexttxdescr] = 1;

	/* are all transmission slots used up ? */
	if (priv->txusedcnt >= TXBUFCNT)
		netif_stop_queue(dev);

	if (priv->txusedcnt == 1)
		StartTx(dev, priv->nexttxdescr);
	priv->nexttxdescr = (priv->nexttxdescr + 1) % TXBUFCNT;

	spin_unlock_irqrestore(&priv->lock, flags);
tx_done:
	dev_kfree_skb(skb);
	return retval;
}

void rt2x00lib_rxdone(struct queue_entry *entry, gfp_t gfp)
{
	struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;
	struct rxdone_entry_desc rxdesc;
	struct sk_buff *skb;
	struct ieee80211_rx_status *rx_status;
	unsigned int header_length;
	int rate_idx;

	if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) ||
	    !test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
		goto submit_entry;

	if (test_bit(ENTRY_DATA_IO_FAILED, &entry->flags))
		goto submit_entry;

	/*
	 * Allocate a new sk_buffer. If no new buffer available, drop the
	 * received frame and reuse the existing buffer.
	 */
	skb = rt2x00queue_alloc_rxskb(entry, gfp);
	if (!skb)
		goto submit_entry;

	/*
	 * Unmap the skb.
	 */
	rt2x00queue_unmap_skb(entry);

	/*
	 * Extract the RXD details.
	 */
	memset(&rxdesc, 0, sizeof(rxdesc));
	rt2x00dev->ops->lib->fill_rxdone(entry, &rxdesc);

	/*
	 * Check for valid size in case we get corrupted descriptor from
	 * hardware.
	 */
	if (unlikely(rxdesc.size == 0 ||
		     rxdesc.size > entry->queue->data_size)) {
		ERROR(rt2x00dev, "Wrong frame size %d max %d.\n",
			rxdesc.size, entry->queue->data_size);
		dev_kfree_skb(entry->skb);
		goto renew_skb;
	}

	/*
	 * The data behind the ieee80211 header must be
	 * aligned on a 4 byte boundary.
	 */
	header_length = ieee80211_get_hdrlen_from_skb(entry->skb);

	/*
	 * Hardware might have stripped the IV/EIV/ICV data,
	 * in that case it is possible that the data was
	 * provided separately (through hardware descriptor)
	 * in which case we should reinsert the data into the frame.
	 */
	if ((rxdesc.dev_flags & RXDONE_CRYPTO_IV) &&
	    (rxdesc.flags & RX_FLAG_IV_STRIPPED))
		rt2x00crypto_rx_insert_iv(entry->skb, header_length,
					  &rxdesc);
	else if (header_length &&
		 (rxdesc.size > header_length) &&
		 (rxdesc.dev_flags & RXDONE_L2PAD))
		rt2x00queue_remove_l2pad(entry->skb, header_length);

	/* Trim buffer to correct size */
	skb_trim(entry->skb, rxdesc.size);

	/*
	 * Translate the signal to the correct bitrate index.
	 */
	rate_idx = rt2x00lib_rxdone_read_signal(rt2x00dev, &rxdesc);
	if (rxdesc.rate_mode == RATE_MODE_HT_MIX ||
	    rxdesc.rate_mode == RATE_MODE_HT_GREENFIELD)
		rxdesc.flags |= RX_FLAG_HT;

	/*
	 * Check if this is a beacon, and more frames have been
	 * buffered while we were in powersaving mode.
	 */
	rt2x00lib_rxdone_check_ps(rt2x00dev, entry->skb, &rxdesc);

	/*
	 * Update extra components
	 */
	rt2x00link_update_stats(rt2x00dev, entry->skb, &rxdesc);
	rt2x00debug_update_crypto(rt2x00dev, &rxdesc);
	rt2x00debug_dump_frame(rt2x00dev, DUMP_FRAME_RXDONE, entry->skb);

	/*
	 * Initialize RX status information, and send frame
	 * to mac80211.
	 */
	rx_status = IEEE80211_SKB_RXCB(entry->skb);

	/* Ensure that all fields of rx_status are initialized
	 * properly. The skb->cb array was used for driver
//.........这里部分代码省略.........

static int sonic_send_packet(struct sk_buff *skb, struct net_device *dev)
{
	struct sonic_local *lp = netdev_priv(dev);
	dma_addr_t laddr;
	int length;
	int entry = lp->next_tx;

	if (sonic_debug > 2)
;

	length = skb->len;
	if (length < ETH_ZLEN) {
		if (skb_padto(skb, ETH_ZLEN))
			return NETDEV_TX_OK;
		length = ETH_ZLEN;
	}

	/*
	 * Map the packet data into the logical DMA address space
	 */

	laddr = dma_map_single(lp->device, skb->data, length, DMA_TO_DEVICE);
	if (!laddr) {
;
		dev_kfree_skb(skb);
		return NETDEV_TX_BUSY;
	}

	sonic_tda_put(dev, entry, SONIC_TD_STATUS, 0);       /* clear status */
	sonic_tda_put(dev, entry, SONIC_TD_FRAG_COUNT, 1);   /* single fragment */
	sonic_tda_put(dev, entry, SONIC_TD_PKTSIZE, length); /* length of packet */
	sonic_tda_put(dev, entry, SONIC_TD_FRAG_PTR_L, laddr & 0xffff);
	sonic_tda_put(dev, entry, SONIC_TD_FRAG_PTR_H, laddr >> 16);
	sonic_tda_put(dev, entry, SONIC_TD_FRAG_SIZE, length);
	sonic_tda_put(dev, entry, SONIC_TD_LINK,
		sonic_tda_get(dev, entry, SONIC_TD_LINK) | SONIC_EOL);

	/*
	 * Must set tx_skb[entry] only after clearing status, and
	 * before clearing EOL and before stopping queue
	 */
	wmb();
	lp->tx_len[entry] = length;
	lp->tx_laddr[entry] = laddr;
	lp->tx_skb[entry] = skb;

	wmb();
	sonic_tda_put(dev, lp->eol_tx, SONIC_TD_LINK,
				  sonic_tda_get(dev, lp->eol_tx, SONIC_TD_LINK) & ~SONIC_EOL);
	lp->eol_tx = entry;

	lp->next_tx = (entry + 1) & SONIC_TDS_MASK;
	if (lp->tx_skb[lp->next_tx] != NULL) {
		/* The ring is full, the ISR has yet to process the next TD. */
		if (sonic_debug > 3)
;
		netif_stop_queue(dev);
		/* after this packet, wait for ISR to free up some TDAs */
	} else netif_start_queue(dev);

	if (sonic_debug > 2)
;

	SONIC_WRITE(SONIC_CMD, SONIC_CR_TXP);

	return NETDEV_TX_OK;
}

static void ri_tasklet(unsigned long dev)
{

    struct net_device *_dev = (struct net_device *)dev;
    struct ifb_private *dp = netdev_priv(_dev);
    struct net_device_stats *stats = &_dev->stats;
    struct netdev_queue *txq;
    struct sk_buff *skb;

    txq = netdev_get_tx_queue(_dev, 0);
    dp->st_task_enter++;
    if ((skb = skb_peek(&dp->tq)) == NULL) {
        dp->st_txq_refl_try++;
        if (__netif_tx_trylock(txq)) {
            dp->st_rxq_enter++;
            while ((skb = skb_dequeue(&dp->rq)) != NULL) {
                skb_queue_tail(&dp->tq, skb);
                dp->st_rx2tx_tran++;
            }
            __netif_tx_unlock(txq);
        } else {
            /* reschedule */
            dp->st_rxq_notenter++;
            goto resched;
        }
    }

    while ((skb = skb_dequeue(&dp->tq)) != NULL) {
        u32 from = G_TC_FROM(skb->tc_verd);

        skb->tc_verd = 0;
        skb->tc_verd = SET_TC_NCLS(skb->tc_verd);
        stats->tx_packets++;
        stats->tx_bytes +=skb->len;

        skb->dev = dev_get_by_index(&init_net, skb->iif);
        if (!skb->dev) {
            dev_kfree_skb(skb);
            stats->tx_dropped++;
            break;
        }
        dev_put(skb->dev);
        skb->iif = _dev->ifindex;

        if (from & AT_EGRESS) {
            dp->st_rx_frm_egr++;
            dev_queue_xmit(skb);
        } else if (from & AT_INGRESS) {
            dp->st_rx_frm_ing++;
            skb_pull(skb, skb->dev->hard_header_len);
            netif_rx(skb);
        } else
            BUG();
    }

    if (__netif_tx_trylock(txq)) {
        dp->st_rxq_check++;
        if ((skb = skb_peek(&dp->rq)) == NULL) {
            dp->tasklet_pending = 0;
            if (netif_queue_stopped(_dev))
                netif_wake_queue(_dev);
        } else {
            dp->st_rxq_rsch++;
            __netif_tx_unlock(txq);
            goto resched;
        }
        __netif_tx_unlock(txq);
    } else {
resched:
        dp->tasklet_pending = 1;
        tasklet_schedule(&dp->ifb_tasklet);
    }

}

static void
tx_d_frame(struct hfc4s8s_l1 *l1p)
{
	struct sk_buff *skb;
	u_char f1, f2;
	u_char *cp;
	long cnt;

	if (l1p->l1_state != 7)
		return;

	/* TX fifo */
	Write_hfc8(l1p->hw, R_FIFO, (l1p->st_num * 8 + 4));
	wait_busy(l1p->hw);

	f1 = Read_hfc8(l1p->hw, A_F1);
	f2 = Read_hfc8_stable(l1p->hw, A_F2);

	if ((f1 ^ f2) & MAX_F_CNT)
		return;		/* fifo is still filled */

	if (l1p->tx_cnt > 0) {
		cnt = l1p->tx_cnt;
		l1p->tx_cnt = 0;
		l1p->d_if.ifc.l1l2(&l1p->d_if.ifc, PH_DATA | CONFIRM,
				   (void *) cnt);
	}

	if ((skb = skb_dequeue(&l1p->d_tx_queue))) {
		cp = skb->data;
		cnt = skb->len;
#ifndef HISAX_HFC4S8S_PCIMEM
		SetRegAddr(l1p->hw, A_FIFO_DATA0);
#endif

		while (cnt >= 4) {
#ifdef HISAX_HFC4S8S_PCIMEM
			fWrite_hfc32(l1p->hw, A_FIFO_DATA0,
				     *(unsigned long *) cp);
#else
			SetRegAddr(l1p->hw, A_FIFO_DATA0);
			fWrite_hfc32(l1p->hw, *(unsigned long *) cp);
#endif
			cp += 4;
			cnt -= 4;
		}

#ifdef HISAX_HFC4S8S_PCIMEM
		while (cnt--)
			fWrite_hfc8(l1p->hw, A_FIFO_DATA0, *cp++);
#else
		while (cnt--)
			fWrite_hfc8(l1p->hw, *cp++);
#endif

		l1p->tx_cnt = skb->truesize;
		Write_hfc8(l1p->hw, A_INC_RES_FIFO, 1);	/* increment f counter */
		wait_busy(l1p->hw);

		dev_kfree_skb(skb);
	}
}				/* tx_d_frame */

//.........这里部分代码省略.........
	if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
		net_alert_ratelimited(
			"xennet: skb->len = %u, too big for wire format\n",
			skb->len);
		goto drop;
	}

	frags += DIV_ROUND_UP(offset + len, PAGE_SIZE);
	if (unlikely(frags > MAX_SKB_FRAGS + 1)) {
		printk(KERN_ALERT "xennet: skb rides the rocket: %d frags\n",
		       frags);
		dump_stack();
		goto drop;
	}

	spin_lock_irqsave(&np->tx_lock, flags);

	if (unlikely(!netif_carrier_ok(dev) ||
		     (frags > 1 && !xennet_can_sg(dev)) ||
		     netif_needs_gso(skb, netif_skb_features(skb)))) {
		spin_unlock_irqrestore(&np->tx_lock, flags);
		goto drop;
	}

	i = np->tx.req_prod_pvt;

	id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
	np->tx_skbs[id].skb = skb;

	tx = RING_GET_REQUEST(&np->tx, i);

	tx->id   = id;
	ref = gnttab_claim_grant_reference(&np->gref_tx_head);
	BUG_ON((signed short)ref < 0);
	mfn = virt_to_mfn(data);
	gnttab_grant_foreign_access_ref(
		ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly);
	tx->gref = np->grant_tx_ref[id] = ref;
	tx->offset = offset;
	tx->size = len;
	extra = NULL;

	tx->flags = 0;
	if (skb->ip_summed == CHECKSUM_PARTIAL)
		/* local packet? */
		tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
	else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
		/* remote but checksummed. */
		tx->flags |= XEN_NETTXF_data_validated;

	if (skb_shinfo(skb)->gso_size) {
		struct xen_netif_extra_info *gso;

		gso = (struct xen_netif_extra_info *)
			RING_GET_REQUEST(&np->tx, ++i);

		if (extra)
			extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
		else
			tx->flags |= XEN_NETTXF_extra_info;

		gso->u.gso.size = skb_shinfo(skb)->gso_size;
		gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
		gso->u.gso.pad = 0;
		gso->u.gso.features = 0;

		gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
		gso->flags = 0;
		extra = gso;
	}

	np->tx.req_prod_pvt = i + 1;

	xennet_make_frags(skb, dev, tx);
	tx->size = skb->len;

	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify);
	if (notify)
		notify_remote_via_irq(np->netdev->irq);

	u64_stats_update_begin(&stats->syncp);
	stats->tx_bytes += skb->len;
	stats->tx_packets++;
	u64_stats_update_end(&stats->syncp);

	/* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
	xennet_tx_buf_gc(dev);

	if (!netfront_tx_slot_available(np))
		netif_stop_queue(dev);

	spin_unlock_irqrestore(&np->tx_lock, flags);

	return NETDEV_TX_OK;

 drop:
	dev->stats.tx_dropped++;
	dev_kfree_skb(skb);
	return NETDEV_TX_OK;
}