On Thu, Jun 06, 2013 at 05:54:39PM +0800, Jason Wang wrote: > 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 <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]> > --- > drivers/net/macvtap.c | 135 +++++++++++++++++++++++++++++++++++++------ > include/linux/if_macvlan.h | 4 + > 2 files changed, 120 insertions(+), 19 deletions(-) > > diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c > index 5ccba99..d2d1d55 100644 > --- a/drivers/net/macvtap.c > +++ b/drivers/net/macvtap.c > @@ -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); > - > - 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; > diff --git a/include/linux/if_macvlan.h b/include/linux/if_macvlan.h > index 62d8bda..1912133 100644 > --- a/include/linux/if_macvlan.h > +++ b/include/linux/if_macvlan.h > @@ -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; > }; > > -- > 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
