From 815f236d622721b54f3963ba59dad98b02cdeabf Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Wed, 5 Jun 2013 23:54:39 +0000 Subject: [PATCH] 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: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- 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 5ccba99b15f4..d2d1d5578b61 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 62d8bda67874..19121331a5ed 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; }; -- 2.20.1