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 <jasow...@redhat.com>
---
drivers/net/macvtap.c | 133 +++++++++++++++++++++++++++++++++++++++-----
include/linux/if_macvlan.h | 4 +
2 files changed, 122 insertions(+), 15 deletions(-)
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 14764cc..355e6ad 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 +87,37 @@ 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++;
+ vlan->numdisabled--;
+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->numvtaps + vlan->numdisabled == MAX_MACVTAP_QUEUES)
goto out;
err = 0;
@@ -102,7 +127,9 @@ 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->tap_link);
vlan->numvtaps++;
@@ -111,6 +138,38 @@ out:
return err;
}
+static int macvtap_disable_queue(struct macvtap_queue *q)
+{
+ struct macvlan_dev *vlan;
+ struct macvtap_queue *nq;
+ int err = 0;
+
+ spin_lock(&macvtap_lock);
+ vlan = rcu_dereference_protected(q->vlan,
+ lockdep_is_held(&macvtap_lock));
+
+ if (!q->enabled) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ if (vlan) {
+ int index = q->queue_index;
+ 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--;
+ vlan->numdisabled++;
+ }
+out:
+ 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
@@ -128,18 +187,24 @@ static void macvtap_put_queue(struct macvtap_queue *q)
vlan = rcu_dereference_protected(q->vlan,
lockdep_is_held(&macvtap_lock));
if (vlan) {
+ int numvtaps = vlan->numvtaps;
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(index >= vlan->numvtaps);
+ nq = rcu_dereference_protected(vlan->taps[numvtaps - 1],
+ lockdep_is_held(&macvtap_lock));
+ rcu_assign_pointer(vlan->taps[index], nq);
+ nq->queue_index = index;
+
+ RCU_INIT_POINTER(vlan->taps[numvtaps - 1], NULL);
+ vlan->numvtaps--;
+ } else
+ vlan->numdisabled--;
- RCU_INIT_POINTER(vlan->taps[vlan->numvtaps - 1], NULL);
RCU_INIT_POINTER(q->vlan, NULL);
sock_put(&q->sk);
- --vlan->numvtaps;
+ list_del_init(&q->next);
}
spin_unlock(&macvtap_lock);
@@ -160,6 +225,10 @@ static struct macvtap_queue *macvtap_get_queue(struct
net_device *dev,
{
struct macvlan_dev *vlan = netdev_priv(dev);
struct macvtap_queue *tap = NULL;
+ /* numvtaps here is just a hint, even if the number of active taps were
+ * reduced in the same sime, since we are protected by rcu read lock,
+ * we're safe here.
+ */
int numvtaps = ACCESS_ONCE(vlan->numvtaps);
__u32 rxq;
@@ -196,20 +265,25 @@ 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->tap_link, 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--;
+ else
+ vlan->numdisabled--;
}
+ for (i = 0; i < vlan->numvtaps; i++)
+ RCU_INIT_POINTER(vlan->taps[i], NULL);
+ BUG_ON(vlan->numvtaps + vlan->numdisabled != 0);
/* guarantee that any future macvtap_set_queue will fail */
vlan->numvtaps = MAX_MACVTAP_QUEUES;
+ vlan->numdisabled = 0;
spin_unlock(&macvtap_lock);
synchronize_rcu();
@@ -298,6 +372,9 @@ 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->tap_link);
+
/* Don't put anything that may fail after macvlan_common_newlink
* because we can't undo what it does.
*/
@@ -926,6 +1003,27 @@ static int macvtap_set_iff(struct file *file, struct
ifreq __user *ifr_u)
return 0;
}
+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 = -EINVAL;
+
+ vlan = macvtap_get_vlan(q);
+ if (!vlan)
+ goto done;
+
+ 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);
+
+done:
+ return ret;
+}
+
/*
* provide compatibility with generic tun/tap interface
*/
@@ -958,6 +1056,11 @@ 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..87b9091 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 tap_link;
int numvtaps;
+ int numdisabled;
int minor;
};
--
1.7.1
--
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