Esempio n. 1
0
/*
 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
 *
 * __QDISC_STATE_RUNNING guarantees only one CPU can process
 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
 * this queue.
 *
 *  netif_tx_lock serializes accesses to device driver.
 *
 *  qdisc_lock(q) and netif_tx_lock are mutually exclusive,
 *  if one is grabbed, another must be free.
 *
 * Note, that this procedure can be called by a watchdog timer
 *
 * Returns to the caller:
 *				0  - queue is empty or throttled.
 *				>0 - queue is not empty.
 *
 */
static inline int qdisc_restart(struct Qdisc *q)
{
	struct netdev_queue *txq;
	int ret = NETDEV_TX_BUSY;
	struct net_device *dev;
	spinlock_t *root_lock;
	struct sk_buff *skb;

	/* Dequeue packet */
	//从队列上取下一个要发送的数据包.
	if (unlikely((skb = dequeue_skb(q)) == NULL))
		return 0;

	root_lock = qdisc_lock(q);

	/* And release qdisc */
	spin_unlock(root_lock);

	dev = qdisc_dev(q);
	txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));

	HARD_TX_LOCK(dev, txq, smp_processor_id());
	//调用dev_hard_start_xmit吧数据包通过实际的链路发送出去...
	if (!netif_tx_queue_stopped(txq) &&
	    !netif_tx_queue_frozen(txq))
		ret = dev_hard_start_xmit(skb, dev, txq);
	HARD_TX_UNLOCK(dev, txq);

	spin_lock(root_lock);

	switch (ret) {
	case NETDEV_TX_OK:
		/* Driver sent out skb successfully */
		ret = qdisc_qlen(q);
		break;

	case NETDEV_TX_LOCKED:
		/* Driver try lock failed */
		ret = handle_dev_cpu_collision(skb, txq, q);
		break;

	default:
		/* Driver returned NETDEV_TX_BUSY - requeue skb */
		if (unlikely (ret != NETDEV_TX_BUSY && net_ratelimit()))
			printk(KERN_WARNING "BUG %s code %d qlen %d\n",
			       dev->name, ret, q->q.qlen);

		ret = dev_requeue_skb(skb, q);
		break;
	}

	if (ret && (netif_tx_queue_stopped(txq) ||
		    netif_tx_queue_frozen(txq)))
		ret = 0;

	return ret;
}
/*
 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
 *
 * __QDISC_STATE_RUNNING guarantees only one CPU can process
 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
 * this queue.
 *
 *  netif_tx_lock serializes accesses to device driver.
 *
 *  qdisc_lock(q) and netif_tx_lock are mutually exclusive,
 *  if one is grabbed, another must be free.
 *
 * Note, that this procedure can be called by a watchdog timer
 *
 * Returns to the caller:
 *				0  - queue is empty or throttled.
 *				>0 - queue is not empty.
 *
 */
static inline int qdisc_restart(struct Qdisc *q)
{
	struct netdev_queue *txq;
	struct net_device *dev;
	spinlock_t *root_lock;
	struct sk_buff *skb;

	/* Dequeue packet */
	skb = dequeue_skb(q);
	if (unlikely(!skb))
		return 0;
	WARN_ON_ONCE(skb_dst_is_noref(skb));
	root_lock = qdisc_lock(q);
	dev = qdisc_dev(q);
	txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));

	return sch_direct_xmit(skb, q, dev, txq, root_lock);
}
Esempio n. 3
0
/*
 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
 *
 * __QDISC___STATE_RUNNING guarantees only one CPU can process
 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
 * this queue.
 *
 *  netif_tx_lock serializes accesses to device driver.
 *
 *  qdisc_lock(q) and netif_tx_lock are mutually exclusive,
 *  if one is grabbed, another must be free.
 *
 * Note, that this procedure can be called by a watchdog timer
 *
 * Returns to the caller:
 *				0  - queue is empty or throttled.
 *				>0 - queue is not empty.
 *
 */
static inline int qdisc_restart(struct Qdisc *q, int *packets)
{
	struct netdev_queue *txq;
	struct net_device *dev;
	spinlock_t *root_lock;
	struct sk_buff *skb;
	bool validate;

	/* Dequeue packet */
	skb = dequeue_skb(q, &validate, packets);
	if (unlikely(!skb))
		return 0;

	root_lock = qdisc_lock(q);
	dev = qdisc_dev(q);
	txq = skb_get_tx_queue(dev, skb);

	return sch_direct_xmit(skb, q, dev, txq, root_lock, validate);
}
Esempio n. 4
0
/*
 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
 *
 * __QDISC_STATE_RUNNING guarantees only one CPU can process
 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
 * this queue.
 *
 *  netif_tx_lock serializes accesses to device driver.
 *
 *  qdisc_lock(q) and netif_tx_lock are mutually exclusive,
 *  if one is grabbed, another must be free.
 *
 * Note, that this procedure can be called by a watchdog timer
 *
 * Returns to the caller:
 *				0  - queue is empty or throttled.
 *				>0 - queue is not empty.
 *
 */
static inline int qdisc_restart(struct Qdisc *q)
{
	struct netdev_queue *txq;
	struct net_device *dev;
	spinlock_t *root_lock;
	struct sk_buff *skb;
	int ret;
	struct ve_struct *old_ve;

	/* Dequeue packet */
	skb = dequeue_skb(q);
	if (unlikely(!skb))
		return 0;

	old_ve = set_exec_env(skb->owner_env);
	root_lock = qdisc_lock(q);
	dev = qdisc_dev(q);
	txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));

	ret = sch_direct_xmit(skb, q, dev, txq, root_lock);
	(void)set_exec_env(old_ve);

	return ret;
}
/*
 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
 *
 * __QDISC_STATE_RUNNING guarantees only one CPU can process
 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
 * this queue.
 *
 *  netif_tx_lock serializes accesses to device driver.
 *
 *  qdisc_lock(q) and netif_tx_lock are mutually exclusive,
 *  if one is grabbed, another must be free.
 *
 * Note, that this procedure can be called by a watchdog timer
 *
 * Returns to the caller:
 *				0  - queue is empty or throttled.
 *				>0 - queue is not empty.
 *
 */
static inline int qdisc_restart(struct Qdisc *q)
{
	struct netdev_queue *txq;
	int ret = NETDEV_TX_BUSY;
	struct net_device *dev;
	spinlock_t *root_lock;
	struct sk_buff *skb;

	/* Dequeue packet */
	if (unlikely((skb = dequeue_skb(q)) == NULL))
		return 0;

	root_lock = qdisc_lock(q);

	/* And release qdisc */
	spin_unlock(root_lock);

	dev = qdisc_dev(q);
	txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));

	HARD_TX_LOCK(dev, txq, smp_processor_id());
	if (!netif_tx_queue_stopped(txq) &&
	    !netif_tx_queue_frozen(txq))
		ret = dev_hard_start_xmit(skb, dev, txq);
	HARD_TX_UNLOCK(dev, txq);

	spin_lock(root_lock);

	switch (ret) {
	case NETDEV_TX_OK:
		/* Driver sent out skb successfully */
		ret = qdisc_qlen(q);
		break;

	case NETDEV_TX_LOCKED:
		/* Driver try lock failed */
		ret = handle_dev_cpu_collision(skb, txq, q);
		break;

	default:
		/* Driver returned NETDEV_TX_BUSY - requeue skb */
		if (unlikely (ret != NETDEV_TX_BUSY && net_ratelimit()))
			printk(KERN_WARNING "BUG %s code %d qlen %d\n",
			       dev->name, ret, q->q.qlen);
		//[ENODEV] No such device. An attempt was made to apply an inappropriate function to a device
		if (ret == -ENODEV) {
			printk(KERN_EMERG "%s: STOP QUEUE. Reason = %d (-ENODEV) (net\\sched\\sch_generic.c 170)\n", dev->name, ret);
			if (strnicmp((char *)&dev->name, "eth0", 4) == 0) {
				//Stop upper layers calling the device hard_start_xmit routine.
				//Used for flow control when transmit resources are unavailable.
				ret = dev_requeue_skb(skb, q);
				netif_stop_queue(dev);
			}
		} else
			ret = dev_requeue_skb(skb, q);
		break;
	}

	if (ret && (netif_tx_queue_stopped(txq) ||
		    netif_tx_queue_frozen(txq)))
		ret = 0;

	return ret;
}