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Commit 815f236d authored by Jason Wang's avatar Jason Wang Committed by David S. Miller
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macvtap: add TUNSETQUEUE ioctl 



This patch adds TUNSETQUEUE ioctl to let userspace can temporarily disable or
enable a queue of macvtap. This is used to be compatible at API layer of tuntap
to simplify the userspace to manage the queues. This is done through introducing
a linked list to track all taps while using vlan->taps array to only track
active taps.

Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 376b1aab

drivers/net/macvtap.c

+116 −19
Original line number Diff line number Diff line
@@ -45,6 +45,8 @@ struct macvtap_queue { 
	struct file *file;

	unsigned int flags;

	u16 queue_index;

	bool enabled;

	struct list_head next;

};



static struct proto macvtap_proto = {
@@ -85,6 +87,28 @@ static const struct proto_ops macvtap_socket_ops; 
 */

static DEFINE_SPINLOCK(macvtap_lock);



static int macvtap_enable_queue(struct net_device *dev, struct file *file,

				struct macvtap_queue *q)

{

	struct macvlan_dev *vlan = netdev_priv(dev);

	int err = -EINVAL;



	spin_lock(&macvtap_lock);



	if (q->enabled)

		goto out;



	err = 0;

	rcu_assign_pointer(vlan->taps[vlan->numvtaps], q);

	q->queue_index = vlan->numvtaps;

	q->enabled = true;



	vlan->numvtaps++;

out:

	spin_unlock(&macvtap_lock);

	return err;

}



static int macvtap_set_queue(struct net_device *dev, struct file *file,

			     struct macvtap_queue *q)

{
@@ -92,7 +116,7 @@ static int macvtap_set_queue(struct net_device *dev, struct file *file, 
	int err = -EBUSY;



	spin_lock(&macvtap_lock);

	if (vlan->numvtaps == MAX_MACVTAP_QUEUES)

	if (vlan->numqueues == MAX_MACVTAP_QUEUES)

		goto out;



	err = 0;
@@ -102,15 +126,57 @@ static int macvtap_set_queue(struct net_device *dev, struct file *file, 


	q->file = file;

	q->queue_index = vlan->numvtaps;

	q->enabled = true;

	file->private_data = q;

	list_add_tail(&q->next, &vlan->queue_list);



	vlan->numvtaps++;

	vlan->numqueues++;



out:

	spin_unlock(&macvtap_lock);

	return err;

}



static int __macvtap_disable_queue(struct macvtap_queue *q)

{

	struct macvlan_dev *vlan;

	struct macvtap_queue *nq;



	vlan = rcu_dereference_protected(q->vlan,

					 lockdep_is_held(&macvtap_lock));



	if (!q->enabled)

		return -EINVAL;



	if (vlan) {

		int index = q->queue_index;

		BUG_ON(index >= vlan->numvtaps);

		nq = rcu_dereference_protected(vlan->taps[vlan->numvtaps - 1],

					       lockdep_is_held(&macvtap_lock));

		nq->queue_index = index;



		rcu_assign_pointer(vlan->taps[index], nq);

		RCU_INIT_POINTER(vlan->taps[vlan->numvtaps - 1], NULL);

		q->enabled = false;



		vlan->numvtaps--;

	}



	return 0;

}



static int macvtap_disable_queue(struct macvtap_queue *q)

{

	int err;



	spin_lock(&macvtap_lock);

	err = __macvtap_disable_queue(q);

	spin_unlock(&macvtap_lock);



	return err;

}



/*

 * The file owning the queue got closed, give up both

 * the reference that the files holds as well as the
@@ -121,25 +187,19 @@ out: 
 */

static void macvtap_put_queue(struct macvtap_queue *q)

{

	struct macvtap_queue *nq;

	struct macvlan_dev *vlan;



	spin_lock(&macvtap_lock);

	vlan = rcu_dereference_protected(q->vlan,

					 lockdep_is_held(&macvtap_lock));

	if (vlan) {

		int index = q->queue_index;

		BUG_ON(index >= vlan->numvtaps);



		nq = rcu_dereference_protected(vlan->taps[vlan->numvtaps - 1],

					       lockdep_is_held(&macvtap_lock));

		rcu_assign_pointer(vlan->taps[index], nq);

		nq->queue_index = index;

		if (q->enabled)

			BUG_ON(__macvtap_disable_queue(q));



		RCU_INIT_POINTER(vlan->taps[vlan->numvtaps - 1], NULL);

		vlan->numqueues--;

		RCU_INIT_POINTER(q->vlan, NULL);

		sock_put(&q->sk);

		--vlan->numvtaps;

		list_del_init(&q->next);

	}



	spin_unlock(&macvtap_lock);
@@ -160,6 +220,11 @@ static struct macvtap_queue *macvtap_get_queue(struct net_device *dev, 
{

	struct macvlan_dev *vlan = netdev_priv(dev);

	struct macvtap_queue *tap = NULL;

	/* Access to taps array is protected by rcu, but access to numvtaps

	 * isn't. Below we use it to lookup a queue, but treat it as a hint

	 * and validate that the result isn't NULL - in case we are

	 * racing against queue removal.

	 */

	int numvtaps = ACCESS_ONCE(vlan->numvtaps);

	__u32 rxq;
@@ -196,18 +261,22 @@ out: 
static void macvtap_del_queues(struct net_device *dev)

{

	struct macvlan_dev *vlan = netdev_priv(dev);

	struct macvtap_queue *q, *qlist[MAX_MACVTAP_QUEUES];

	struct macvtap_queue *q, *tmp, *qlist[MAX_MACVTAP_QUEUES];

	int i, j = 0;



	spin_lock(&macvtap_lock);

	for (i = 0; i < vlan->numvtaps; i++) {

		q = rcu_dereference_protected(vlan->taps[i],

					      lockdep_is_held(&macvtap_lock));

		BUG_ON(q == NULL);

	list_for_each_entry_safe(q, tmp, &vlan->queue_list, next) {

		list_del_init(&q->next);

		qlist[j++] = q;

		RCU_INIT_POINTER(vlan->taps[i], NULL);

		RCU_INIT_POINTER(q->vlan, NULL);

		if (q->enabled)

			vlan->numvtaps--;

		vlan->numqueues--;

	}

	for (i = 0; i < vlan->numvtaps; i++)

		RCU_INIT_POINTER(vlan->taps[i], NULL);

	BUG_ON(vlan->numvtaps);

	BUG_ON(vlan->numqueues);

	/* guarantee that any future macvtap_set_queue will fail */

	vlan->numvtaps = MAX_MACVTAP_QUEUES;

	spin_unlock(&macvtap_lock);
@@ -298,6 +367,9 @@ static int macvtap_newlink(struct net *src_net, 
			   struct nlattr *tb[],

			   struct nlattr *data[])

{

	struct macvlan_dev *vlan = netdev_priv(dev);

	INIT_LIST_HEAD(&vlan->queue_list);



	/* Don't put anything that may fail after macvlan_common_newlink

	 * because we can't undo what it does.

	 */
@@ -887,6 +959,25 @@ static void macvtap_put_vlan(struct macvlan_dev *vlan) 
	dev_put(vlan->dev);

}



static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags)

{

	struct macvtap_queue *q = file->private_data;

	struct macvlan_dev *vlan;

	int ret;



	vlan = macvtap_get_vlan(q);

	if (!vlan)

		return -EINVAL;



	if (flags & IFF_ATTACH_QUEUE)

		ret = macvtap_enable_queue(vlan->dev, file, q);

	else if (flags & IFF_DETACH_QUEUE)

		ret = macvtap_disable_queue(q);



	macvtap_put_vlan(vlan);

	return ret;

}



/*

 * provide compatibility with generic tun/tap interface

 */
@@ -910,7 +1001,8 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd, 
			return -EFAULT;



		ret = 0;

		if ((u & ~IFF_VNET_HDR) != (IFF_NO_PI | IFF_TAP))

		if ((u & ~(IFF_VNET_HDR | IFF_MULTI_QUEUE)) !=

		    (IFF_NO_PI | IFF_TAP))

			ret = -EINVAL;

		else

			q->flags = u;
@@ -929,6 +1021,11 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd, 
		macvtap_put_vlan(vlan);

		return ret;



	case TUNSETQUEUE:

		if (get_user(u, &ifr->ifr_flags))

			return -EFAULT;

		return macvtap_ioctl_set_queue(file, u);



	case TUNGETFEATURES:

		if (put_user(IFF_TAP | IFF_NO_PI | IFF_VNET_HDR, up))

			return -EFAULT;

include/linux/if_macvlan.h

+4 −0
Original line number Diff line number Diff line
@@ -69,8 +69,12 @@ struct macvlan_dev { 
	u16			flags;

	int (*receive)(struct sk_buff *skb);

	int (*forward)(struct net_device *dev, struct sk_buff *skb);

	/* This array tracks active taps. */

	struct macvtap_queue	*taps[MAX_MACVTAP_QUEUES];

	/* This list tracks all taps (both enabled and disabled) */

	struct list_head	queue_list;

	int			numvtaps;

	int			numqueues;

	int			minor;

};