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macvtap: add TUNSETQUEUE ioctl

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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: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jason Wang 2013-06-05 23:54:39 +00:00 committed by David S. Miller
parent 376b1aabe1
commit 815f236d62
2 changed files with 120 additions and 19 deletions
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135
drivers/net/macvtap.c
View File

@ -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 = {
@ -85,14 +87,36 @@ static const struct proto_ops macvtap_socket_ops;
*/
static DEFINE_SPINLOCK(macvtap_lock);
static int macvtap_set_queue(struct net_device *dev, struct file *file,
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)
{
struct macvlan_dev *vlan = netdev_priv(dev);
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);
if (q->enabled)
BUG_ON(__macvtap_disable_queue(q));
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;
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;

4
include/linux/if_macvlan.h
View File

@ -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;
};