C++ skb_padto函数代码示例

static int net_send_packet(struct sk_buff *skb, struct net_device *dev)
{
	struct net_local *lp = dev->priv;
	int ioaddr = dev->base_addr;
	short length = skb->len;
	unsigned char *buf;
	unsigned long flags;

	/* Block a transmit from overlapping.  */
	
	if (length > ETH_FRAME_LEN) {
		if (net_debug)
			printk("%s: Attempting to send a large packet (%d bytes).\n",
				dev->name, length);
		return 1;
	}
	
	if (length < ETH_ZLEN)
	{
		skb = skb_padto(skb, ETH_ZLEN);
		if(skb == NULL)
			return 0;
		length = ETH_ZLEN;
	}
	buf = skb->data;
	
	if (net_debug > 4)
		printk("%s: Transmitting a packet of length %lu.\n", dev->name,
			   (unsigned long)skb->len);
	/* We may not start transmitting unless we finish transferring
	   a packet into the Tx queue. During executing the following
	   codes we possibly catch a Tx interrupt. Thus we flag off
	   tx_queue_ready, so that we prevent the interrupt routine
	   (net_interrupt) to start transmitting. */
	spin_lock_irqsave(&lp->lock, flags);
	lp->tx_queue_ready = 0;
	{
		outw(length, ioaddr + DATAPORT);
		outsw(ioaddr + DATAPORT, buf, (length + 1) >> 1);
		lp->tx_queue++;
		lp->tx_queue_len += length + 2;
	}
	lp->tx_queue_ready = 1;
	spin_unlock_irqrestore(&lp->lock, flags);

	if (lp->tx_started == 0) {
		/* If the Tx is idle, always trigger a transmit. */
		outb(0x80 | lp->tx_queue, ioaddr + TX_START);
		lp->tx_queue = 0;
		lp->tx_queue_len = 0;
		dev->trans_start = jiffies;
		lp->tx_started = 1;
	} else if (lp->tx_queue_len < 4096 - 1502)
		/* Yes, there is room for one more packet. */
	else
		netif_stop_queue(dev);

	dev_kfree_skb(skb);
	return 0;
}

static int seeq8005_send_packet(struct sk_buff *skb, struct net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);
	short length = skb->len;
	unsigned char *buf;

	if (length < ETH_ZLEN) {
		skb = skb_padto(skb, ETH_ZLEN);
		if (skb == NULL)
			return 0;
		length = ETH_ZLEN;
	}
	buf = skb->data;

	/* Block a timer-based transmit from overlapping */
	netif_stop_queue(dev);
	
	hardware_send_packet(dev, buf, length); 
	dev->trans_start = jiffies;
	lp->stats.tx_bytes += length;
	dev_kfree_skb (skb);
	/* You might need to clean up and record Tx statistics here. */

	return 0;
}

static netdev_tx_t cpsw_ndo_start_xmit(struct sk_buff *skb,
				       struct net_device *ndev)
{
	struct cpsw_priv *priv = netdev_priv(ndev);
	int ret;

	ndev->trans_start = jiffies;

	if (skb_padto(skb, CPSW_MIN_PACKET_SIZE)) {
		cpsw_err(priv, tx_err, "packet pad failed\n");
		priv->stats.tx_dropped++;
		return NETDEV_TX_OK;
	}

	ret = cpdma_chan_submit(priv->txch, skb, skb->data,
				skb->len, GFP_KERNEL);
	if (unlikely(ret != 0)) {
		cpsw_err(priv, tx_err, "desc submit failed\n");
		goto fail;
	}

	return NETDEV_TX_OK;
fail:
	priv->stats.tx_dropped++;
	netif_stop_queue(ndev);
	return NETDEV_TX_BUSY;
}

/**********************************************************************
*%FUNCTION: addTag
*%ARGUMENTS:
* m -- a PPPoE packet
* tag -- tag to add
*%RETURNS:
* -1 if no room in packet; number of bytes added otherwise.
*%DESCRIPTION:
* Inserts a tag as the first tag in a PPPoE packet.
***********************************************************************/
int
addTag(struct sk_buff **m, PPPoETag const *tag)
{
    int len = ntohs(tag->length) + TAG_HDR_SIZE;
    PPPoEPacket *packet = MTOD(*m, PPPoEPacket *);
    int new_size, offset;
    struct sk_buff *skb;
    
    if (len + ntohs(packet->length) > MAX_PPPOE_PAYLOAD)
	return -1;
    offset = HDR_SIZE + ntohs(packet->length);
    new_size = len + offset;
    skb = skb_padto(*m, new_size);
    if (!skb)
	return -1;
    if (new_size > skb->len)
	skb_put(skb, new_size - skb->len);
    memcpy(skb->data + offset, (u8 *)tag, len);
    *m = skb;
    
    /* In case buf was realloced... */
    packet = MTOD(*m, PPPoEPacket *);
    packet->length = htons(ntohs(packet->length) + len);
    return 0;
}

static int
ramips_eth_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct raeth_priv *re = netdev_priv(dev);
	struct raeth_tx_info *txi, *txi_next;
	struct ramips_tx_dma *txd, *txd_next;
	unsigned long tx;
	unsigned int tx_next;
	dma_addr_t mapped_addr;

	if (re->plat->min_pkt_len) {
		if (skb->len < re->plat->min_pkt_len) {
			if (skb_padto(skb, re->plat->min_pkt_len)) {
				printk(KERN_ERR
				       "ramips_eth: skb_padto failed\n");
				kfree_skb(skb);
				return 0;
			}
			skb_put(skb, re->plat->min_pkt_len - skb->len);
		}
	}

	dev->trans_start = jiffies;
	mapped_addr = dma_map_single(&re->netdev->dev, skb->data, skb->len,
				     DMA_TO_DEVICE);

	spin_lock(&re->page_lock);
	tx = ramips_fe_trr(RAETH_REG_TX_CTX_IDX0);
	tx_next = (tx + 1) % NUM_TX_DESC;

	txi = &re->tx_info[tx];
	txd = txi->tx_desc;
	txi_next = &re->tx_info[tx_next];
	txd_next = txi_next->tx_desc;

	if ((txi->tx_skb) || (txi_next->tx_skb) ||
	    !(txd->txd2 & TX_DMA_DONE) ||
	    !(txd_next->txd2 & TX_DMA_DONE))
		goto out;

	txi->tx_skb = skb;

	txd->txd1 = (unsigned int) mapped_addr;
	wmb();
	txd->txd2 = TX_DMA_LSO | TX_DMA_PLEN0(skb->len);
	dev->stats.tx_packets++;
	dev->stats.tx_bytes += skb->len;
	ramips_fe_twr(tx_next, RAETH_REG_TX_CTX_IDX0);
	netdev_sent_queue(dev, skb->len);
	spin_unlock(&re->page_lock);
	return NETDEV_TX_OK;

 out:
	spin_unlock(&re->page_lock);
	dev->stats.tx_dropped++;
	kfree_skb(skb);
	return NETDEV_TX_OK;
}

/**
 * arc_emac_tx - Starts the data transmission.
 * @skb:	sk_buff pointer that contains data to be Transmitted.
 * @ndev:	Pointer to net_device structure.
 *
 * returns: NETDEV_TX_OK, on success
 *		NETDEV_TX_BUSY, if any of the descriptors are not free.
 *
 * This function is invoked from upper layers to initiate transmission.
 */
static int arc_emac_tx(struct sk_buff *skb, struct net_device *ndev)
{
	struct arc_emac_priv *priv = netdev_priv(ndev);
	unsigned int len, *txbd_curr = &priv->txbd_curr;
	struct net_device_stats *stats = &priv->stats;
	__le32 *info = &priv->txbd[*txbd_curr].info;
	dma_addr_t addr;

	if (skb_padto(skb, ETH_ZLEN))
		return NETDEV_TX_OK;

	len = max_t(unsigned int, ETH_ZLEN, skb->len);

	/* EMAC still holds this buffer in its possession.
	 * CPU must not modify this buffer descriptor
	 */
	if (unlikely((le32_to_cpu(*info) & OWN_MASK) == FOR_EMAC)) {
		netif_stop_queue(ndev);
		return NETDEV_TX_BUSY;
	}

	addr = dma_map_single(&ndev->dev, (void *)skb->data, len,
			      DMA_TO_DEVICE);

	if (unlikely(dma_mapping_error(&ndev->dev, addr))) {
		stats->tx_dropped++;
		stats->tx_errors++;
		dev_kfree_skb(skb);
		return NETDEV_TX_OK;
	}
	dma_unmap_addr_set(&priv->tx_buff[*txbd_curr], addr, addr);
	dma_unmap_len_set(&priv->tx_buff[*txbd_curr], len, len);

	priv->tx_buff[*txbd_curr].skb = skb;
	priv->txbd[*txbd_curr].data = cpu_to_le32(addr);

	/* Make sure pointer to data buffer is set */
	wmb();

	skb_tx_timestamp(skb);

	*info = cpu_to_le32(FOR_EMAC | FIRST_OR_LAST_MASK | len);

	/* Increment index to point to the next BD */
	*txbd_curr = (*txbd_curr + 1) % TX_BD_NUM;

	/* Get "info" of the next BD */
	info = &priv->txbd[*txbd_curr].info;

	/* Check if if Tx BD ring is full - next BD is still owned by EMAC */
	if (unlikely((le32_to_cpu(*info) & OWN_MASK) == FOR_EMAC))
		netif_stop_queue(ndev);

	arc_reg_set(priv, R_STATUS, TXPL_MASK);

	return NETDEV_TX_OK;
}

static int cpmac_start_xmit(struct sk_buff *skb)
{
	int queue, len, ret;
	lock_s(l1);
	//struct cpmac_desc *desc;
	//struct cpmac_priv *priv = netdev_priv(dev);

	//if (unlikely(atomic_read(reset_pending)))
	//	return NETDEV_TX_BUSY;


        //cpmac_write(CPMAC_TX_PTR(queue), (u32)desc_ring[queue].mapping);

        // BUG: move this line to the  *** location below
        notify(cond_irq_can_happen);

	if (unlikely(skb_padto(skb, ETH_ZLEN))) {
            ret = NETDEV_TX_OK;
        } else {
            len = max(skb->len, ETH_ZLEN);
            //queue = skb_get_queue_mapping(skb);
            netif_stop_subqueue(/*queue*/);

            //desc = &desc_ring[queue];
            if (unlikely(desc_ring[queue].dataflags & CPMAC_OWN)) {
    //		if (netif_msg_tx_err(priv) && net_ratelimit())
    //			netdev_warn(dev, "tx dma ring full\n");

                    ret = NETDEV_TX_BUSY;
            } else {

                spin_lock(cplock);
                spin_unlock(cplock);
                desc_ring[queue].dataflags = CPMAC_SOP | CPMAC_EOP | CPMAC_OWN;
                desc_ring[queue].skb = skb;
                desc_ring[queue].data_mapping = dma_map_single(skb->data, len,
                                                    DMA_TO_DEVICE);
                desc_ring[queue].hw_data = (u32)desc_ring[queue].data_mapping;
                desc_ring[queue].datalen = len;
                desc_ring[queue].buflen = len;
        //	if (unlikely(netif_msg_tx_queued(priv)))
        //		netdev_dbg(dev, "sending 0x%p, len=%d\n", skb, skb->len);
        //	if (unlikely(netif_msg_hw(priv)))
        //		cpmac_dump_desc(dev, &desc_ring[queue]);
        //	if (unlikely(netif_msg_pktdata(priv)))
        //		cpmac_dump_skb(dev, skb);
	

                ret = NETDEV_TX_OK;
            }
        }
        // ***
        unlock_s(l1);
        return ret;
}

static int epic_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct epic_private *ep = dev->priv;
	int entry, free_count;
	u32 ctrl_word;
	unsigned long flags;

	if (skb_padto(skb, ETH_ZLEN))
		return 0;

	/* Caution: the write order is important here, set the field with the
	   "ownership" bit last. */

	/* Calculate the next Tx descriptor entry. */
	spin_lock_irqsave(&ep->lock, flags);
	free_count = ep->cur_tx - ep->dirty_tx;
	entry = ep->cur_tx % TX_RING_SIZE;

	ep->tx_skbuff[entry] = skb;
	ep->tx_ring[entry].bufaddr = pci_map_single(ep->pci_dev, skb->data,
		 			            skb->len, PCI_DMA_TODEVICE);
	if (free_count < TX_QUEUE_LEN/2) {/* Typical path */
		ctrl_word = cpu_to_le32(0x100000); /* No interrupt */
	} else if (free_count == TX_QUEUE_LEN/2) {
		ctrl_word = cpu_to_le32(0x140000); /* Tx-done intr. */
	} else if (free_count < TX_QUEUE_LEN - 1) {
		ctrl_word = cpu_to_le32(0x100000); /* No Tx-done intr. */
	} else {
		/* Leave room for an additional entry. */
		ctrl_word = cpu_to_le32(0x140000); /* Tx-done intr. */
		ep->tx_full = 1;
	}
	ep->tx_ring[entry].buflength = ctrl_word | cpu_to_le32(skb->len);
	ep->tx_ring[entry].txstatus =
		((skb->len >= ETH_ZLEN ? skb->len : ETH_ZLEN) << 16)
		| cpu_to_le32(DescOwn);

	ep->cur_tx++;
	if (ep->tx_full)
		netif_stop_queue(dev);

	spin_unlock_irqrestore(&ep->lock, flags);
	/* Trigger an immediate transmit demand. */
	outl(TxQueued, dev->base_addr + COMMAND);

	dev->trans_start = jiffies;
	if (debug > 4)
		printk(KERN_DEBUG "%s: Queued Tx packet size %d to slot %d, "
			   "flag %2.2x Tx status %8.8x.\n",
			   dev->name, (int)skb->len, entry, ctrl_word,
			   (int)inl(dev->base_addr + TxSTAT));

	return 0;
}

static int
rtl8169_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
    struct rtl8169_private *tp = dev->priv;
    void *ioaddr = tp->mmio_addr;
    int entry = tp->cur_tx % NUM_TX_DESC;
    u32 len = skb->len;

    if (unlikely(skb->len < ETH_ZLEN)) {
        skb = skb_padto(skb, ETH_ZLEN);
        if (!skb)
            goto err_update_stats;
        len = ETH_ZLEN;
    }

    spin_lock_irq(&tp->lock);

    if (!(le32_to_cpu(tp->TxDescArray[entry].status) & OWNbit)) {
        dma_addr_t mapping;

        mapping = pci_map_single(tp->pci_dev, skb->data, len,
                                 PCI_DMA_TODEVICE);

        tp->Tx_skbuff[entry] = skb;
        tp->TxDescArray[entry].addr = cpu_to_le64(mapping);

        tp->TxDescArray[entry].status = cpu_to_le32(OWNbit | FSbit |
                                        LSbit | len | (EORbit * !((entry + 1) % NUM_TX_DESC)));

        RTL_W8(TxPoll, 0x40);	//set polling bit

        dev->trans_start = jiffies;

        tp->cur_tx++;
    } else
        goto err_drop;


    if ((tp->cur_tx - NUM_TX_DESC) == tp->dirty_tx) {
        netif_stop_queue(dev);
    }
out:
    spin_unlock_irq(&tp->lock);

    return 0;

err_drop:
    dev_kfree_skb(skb);
err_update_stats:
    tp->stats.tx_dropped++;
    goto out;
}

static int
ramips_eth_hard_start_xmit(struct sk_buff* skb, struct net_device *dev)
{
	struct raeth_priv *priv = netdev_priv(dev);
	unsigned long tx;
	unsigned int tx_next;
	unsigned int mapped_addr;
	unsigned long flags;

	if(priv->plat->min_pkt_len)
	{
		if(skb->len < priv->plat->min_pkt_len)
		 {
		     if(skb_padto(skb, priv->plat->min_pkt_len))
			 {
				 printk(KERN_ERR "ramips_eth: skb_padto failed\n");
				 kfree_skb(skb);
				 return 0;
			 }
		     skb_put(skb, priv->plat->min_pkt_len - skb->len);
		 }
	}
	dev->trans_start = jiffies;
	mapped_addr = (unsigned int)dma_map_single(NULL, skb->data, skb->len,
			DMA_TO_DEVICE);
	dma_sync_single_for_device(NULL, mapped_addr, skb->len, DMA_TO_DEVICE);
	spin_lock_irqsave(&priv->page_lock, flags);
	tx = ramips_fe_rr(RAMIPS_TX_CTX_IDX0);
	if(tx == NUM_TX_DESC - 1)
		tx_next = 0;
	else
		tx_next = tx + 1;
	if((priv->tx_skb[tx]) || (priv->tx_skb[tx_next]) ||
		!(priv->tx[tx].txd2 & TX_DMA_DONE) || !(priv->tx[tx_next].txd2 & TX_DMA_DONE))
		goto out;
	priv->tx[tx].txd1 = mapped_addr;
	priv->tx[tx].txd2 &= ~(TX_DMA_PLEN0_MASK | TX_DMA_DONE);
	priv->tx[tx].txd2 |= TX_DMA_PLEN0(skb->len);
	dev->stats.tx_packets++;
	dev->stats.tx_bytes += skb->len;
	priv->tx_skb[tx] = skb;
	wmb();
	ramips_fe_wr((tx + 1) % NUM_TX_DESC, RAMIPS_TX_CTX_IDX0);
	spin_unlock_irqrestore(&priv->page_lock, flags);
	return NETDEV_TX_OK;
out:
	spin_unlock_irqrestore(&priv->page_lock, flags);
	dev->stats.tx_dropped++;
	kfree_skb(skb);
	return NETDEV_TX_OK;
}

static int cpmac_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	int queue, len;
	struct cpmac_desc *desc;
	struct cpmac_priv *priv = netdev_priv(dev);

	if (unlikely(atomic_read(&priv->reset_pending)))
		return NETDEV_TX_BUSY;

	if (unlikely(skb_padto(skb, ETH_ZLEN)))
		return NETDEV_TX_OK;

	len = max(skb->len, ETH_ZLEN);
	queue = skb_get_queue_mapping(skb);
#ifdef CONFIG_NETDEVICES_MULTIQUEUE
	netif_stop_subqueue(dev, queue);
#else
	netif_stop_queue(dev);
#endif

	desc = &priv->desc_ring[queue];
	if (unlikely(desc->dataflags & CPMAC_OWN)) {
		if (netif_msg_tx_err(priv) && net_ratelimit())
			printk(KERN_WARNING "%s: tx dma ring full\n",
			       dev->name);
		return NETDEV_TX_BUSY;
	}

	spin_lock(&priv->lock);
	dev->trans_start = jiffies;
	spin_unlock(&priv->lock);
	desc->dataflags = CPMAC_SOP | CPMAC_EOP | CPMAC_OWN;
	desc->skb = skb;
	desc->data_mapping = dma_map_single(&dev->dev, skb->data, len,
					    DMA_TO_DEVICE);
	desc->hw_data = (u32)desc->data_mapping;
	desc->datalen = len;
	desc->buflen = len;
	if (unlikely(netif_msg_tx_queued(priv)))
		printk(KERN_DEBUG "%s: sending 0x%p, len=%d\n", dev->name, skb,
		       skb->len);
	if (unlikely(netif_msg_hw(priv)))
		cpmac_dump_desc(dev, desc);
	if (unlikely(netif_msg_pktdata(priv)))
		cpmac_dump_skb(dev, skb);
	cpmac_write(priv->regs, CPMAC_TX_PTR(queue), (u32)desc->mapping);

	return NETDEV_TX_OK;
}

static int mc32_send_packet(struct sk_buff *skb, struct net_device *dev)
{
	struct mc32_local *lp = netdev_priv(dev);
	u32 head = atomic_read(&lp->tx_ring_head);
	
	volatile struct skb_header *p, *np;

	netif_stop_queue(dev);

	if(atomic_read(&lp->tx_count)==0) {
		return 1;
	}

	skb = skb_padto(skb, ETH_ZLEN);
	if (skb == NULL) {
		netif_wake_queue(dev);
		return 0;
	}

	atomic_dec(&lp->tx_count); 

	/* P is the last sending/sent buffer as a pointer */
	p=lp->tx_ring[head].p;
		
	head = next_tx(head);

	/* NP is the buffer we will be loading */
	np=lp->tx_ring[head].p; 
	
	/* We will need this to flush the buffer out */
	lp->tx_ring[head].skb=skb;

	np->length      = unlikely(skb->len < ETH_ZLEN) ? ETH_ZLEN : skb->len;			
	np->data	= isa_virt_to_bus(skb->data);
	np->status	= 0;
	np->control     = CONTROL_EOP | CONTROL_EOL;     
	wmb();
		
	/*
	 * The new frame has been setup; we can now
	 * let the interrupt handler and card "see" it
	 */

	atomic_set(&lp->tx_ring_head, head); 
	p->control     &= ~CONTROL_EOL;

	netif_wake_queue(dev);
	return 0;
}

static netdev_tx_t eepro_send_packet(struct sk_buff *skb,
				     struct net_device *dev)
{
	struct eepro_local *lp = netdev_priv(dev);
	unsigned long flags;
	int ioaddr = dev->base_addr;
	short length = skb->len;

	if (net_debug > 5)
		printk(KERN_DEBUG  "%s: entering eepro_send_packet routine.\n", dev->name);

	if (length < ETH_ZLEN) {
		if (skb_padto(skb, ETH_ZLEN))
			return NETDEV_TX_OK;
		length = ETH_ZLEN;
	}
	netif_stop_queue (dev);

	eepro_dis_int(ioaddr);
	spin_lock_irqsave(&lp->lock, flags);

	{
		unsigned char *buf = skb->data;

		if (hardware_send_packet(dev, buf, length))
			/* we won't wake queue here because we're out of space */
			dev->stats.tx_dropped++;
		else {
			dev->stats.tx_bytes+=skb->len;
			netif_wake_queue(dev);
		}

	}

	dev_kfree_skb (skb);

	/* You might need to clean up and record Tx statistics here. */
	/* dev->stats.tx_aborted_errors++; */

	if (net_debug > 5)
		printk(KERN_DEBUG "%s: exiting eepro_send_packet routine.\n", dev->name);

	eepro_en_int(ioaddr);
	spin_unlock_irqrestore(&lp->lock, flags);

	return NETDEV_TX_OK;
}

static int znet_send_packet(struct sk_buff *skb, struct net_device *dev)
{
	int ioaddr = dev->base_addr;
	struct znet_private *znet = dev->priv;
	unsigned long flags;
	short length = skb->len;

	if (znet_debug > 4)
		printk(KERN_DEBUG "%s: ZNet_send_packet.\n", dev->name);

	if (length < ETH_ZLEN) {
		skb = skb_padto(skb, ETH_ZLEN);
		if (skb == NULL)
			return 0;
		length = ETH_ZLEN;
	}
	
	netif_stop_queue (dev);
	
	/* Check that the part hasn't reset itself, probably from suspend. */
	outb(CR0_STATUS_0, ioaddr);
	if (inw(ioaddr) == 0x0010 &&
	    inw(ioaddr) == 0x0000 &&
	    inw(ioaddr) == 0x0010) {
		if (znet_debug > 1)
			printk (KERN_WARNING "%s : waking up\n", dev->name);
		hardware_init(dev);
		znet_transceiver_power (dev, 1);
	}

	if (1) {
		unsigned char *buf = (void *)skb->data;
		ushort *tx_link = znet->tx_cur - 1;
		ushort rnd_len = (length + 1)>>1;
		
		znet->stats.tx_bytes+=length;

		if (znet->tx_cur >= znet->tx_end)
		  znet->tx_cur = znet->tx_start;
		*znet->tx_cur++ = length;
		if (znet->tx_cur + rnd_len + 1 > znet->tx_end) {
			int semi_cnt = (znet->tx_end - znet->tx_cur)<<1; /* Cvrt to byte cnt. */
			memcpy(znet->tx_cur, buf, semi_cnt);
			rnd_len -= semi_cnt>>1;
			memcpy(znet->tx_start, buf + semi_cnt, length - semi_cnt);
			znet->tx_cur = znet->tx_start + rnd_len;
		} else {

static bool rt2x00usb_kick_tx_entry(struct queue_entry *entry, void *data)
{
	struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;
	struct usb_device *usb_dev = to_usb_device_intf(rt2x00dev->dev);
	struct queue_entry_priv_usb *entry_priv = entry->priv_data;
	u32 length;
	int status;

	if (!test_and_clear_bit(ENTRY_DATA_PENDING, &entry->flags) ||
	    test_bit(ENTRY_DATA_STATUS_PENDING, &entry->flags))
		return false;

	/*
	 * USB devices require certain padding at the end of each frame
	 * and urb. Those paddings are not included in skbs. Pass entry
	 * to the driver to determine what the overall length should be.
	 */
	length = rt2x00dev->ops->lib->get_tx_data_len(entry);

	status = skb_padto(entry->skb, length);
	if (unlikely(status)) {
		/* TODO: report something more appropriate than IO_FAILED. */
		rt2x00_warn(rt2x00dev, "TX SKB padding error, out of memory\n");
		set_bit(ENTRY_DATA_IO_FAILED, &entry->flags);
		rt2x00lib_dmadone(entry);

		return false;
	}

	usb_fill_bulk_urb(entry_priv->urb, usb_dev,
			  usb_sndbulkpipe(usb_dev, entry->queue->usb_endpoint),
			  entry->skb->data, length,
			  rt2x00usb_interrupt_txdone, entry);

	usb_anchor_urb(entry_priv->urb, rt2x00dev->anchor);
	status = usb_submit_urb(entry_priv->urb, GFP_ATOMIC);
	if (status) {
		usb_unanchor_urb(entry_priv->urb);
		if (status == -ENODEV)
			clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags);
		set_bit(ENTRY_DATA_IO_FAILED, &entry->flags);
		rt2x00lib_dmadone(entry);
	}

	return false;
}