]> git.karo-electronics.de Git - karo-tx-linux.git/blobdiff - drivers/net/macvtap.c
Merge tag 'char-misc-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregk...
[karo-tx-linux.git] / drivers / net / macvtap.c
index c27011bbe30c52d2eb892ab0d86f8cf3d6f4deb9..da85057680d6575e52eb5d04441dfd394e56e77a 100644 (file)
@@ -1,5 +1,6 @@
 #include <linux/etherdevice.h>
 #include <linux/if_macvlan.h>
+#include <linux/if_tap.h>
 #include <linux/if_vlan.h>
 #include <linux/interrupt.h>
 #include <linux/nsproxy.h>
@@ -8,7 +9,7 @@
 #include <linux/module.h>
 #include <linux/skbuff.h>
 #include <linux/cache.h>
-#include <linux/sched.h>
+#include <linux/sched/signal.h>
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/wait.h>
 #include <linux/virtio_net.h>
 #include <linux/skb_array.h>
 
-/*
- * A macvtap queue is the central object of this driver, it connects
- * an open character device to a macvlan interface. There can be
- * multiple queues on one interface, which map back to queues
- * implemented in hardware on the underlying device.
- *
- * macvtap_proto is used to allocate queues through the sock allocation
- * mechanism.
- *
- */
-struct macvtap_queue {
-       struct sock sk;
-       struct socket sock;
-       struct socket_wq wq;
-       int vnet_hdr_sz;
-       struct macvlan_dev __rcu *vlan;
-       struct file *file;
-       unsigned int flags;
-       u16 queue_index;
-       bool enabled;
-       struct list_head next;
-       struct skb_array skb_array;
-};
-
-#define MACVTAP_FEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE)
-
-#define MACVTAP_VNET_LE 0x80000000
-#define MACVTAP_VNET_BE 0x40000000
-
-#ifdef CONFIG_TUN_VNET_CROSS_LE
-static inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q)
-{
-       return q->flags & MACVTAP_VNET_BE ? false :
-               virtio_legacy_is_little_endian();
-}
-
-static long macvtap_get_vnet_be(struct macvtap_queue *q, int __user *sp)
-{
-       int s = !!(q->flags & MACVTAP_VNET_BE);
-
-       if (put_user(s, sp))
-               return -EFAULT;
-
-       return 0;
-}
-
-static long macvtap_set_vnet_be(struct macvtap_queue *q, int __user *sp)
-{
-       int s;
-
-       if (get_user(s, sp))
-               return -EFAULT;
-
-       if (s)
-               q->flags |= MACVTAP_VNET_BE;
-       else
-               q->flags &= ~MACVTAP_VNET_BE;
-
-       return 0;
-}
-#else
-static inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q)
-{
-       return virtio_legacy_is_little_endian();
-}
-
-static long macvtap_get_vnet_be(struct macvtap_queue *q, int __user *argp)
-{
-       return -EINVAL;
-}
-
-static long macvtap_set_vnet_be(struct macvtap_queue *q, int __user *argp)
-{
-       return -EINVAL;
-}
-#endif /* CONFIG_TUN_VNET_CROSS_LE */
-
-static inline bool macvtap_is_little_endian(struct macvtap_queue *q)
-{
-       return q->flags & MACVTAP_VNET_LE ||
-               macvtap_legacy_is_little_endian(q);
-}
-
-static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val)
-{
-       return __virtio16_to_cpu(macvtap_is_little_endian(q), val);
-}
-
-static inline __virtio16 cpu_to_macvtap16(struct macvtap_queue *q, u16 val)
-{
-       return __cpu_to_virtio16(macvtap_is_little_endian(q), val);
-}
-
-static struct proto macvtap_proto = {
-       .name = "macvtap",
-       .owner = THIS_MODULE,
-       .obj_size = sizeof (struct macvtap_queue),
+struct macvtap_dev {
+       struct macvlan_dev vlan;
+       struct tap_dev    tap;
 };
 
 /*
  * Variables for dealing with macvtaps device numbers.
  */
 static dev_t macvtap_major;
-#define MACVTAP_NUM_DEVS (1U << MINORBITS)
-static DEFINE_MUTEX(minor_lock);
-static DEFINE_IDR(minor_idr);
 
-#define GOODCOPY_LEN 128
 static const void *macvtap_net_namespace(struct device *d)
 {
        struct net_device *dev = to_net_dev(d->parent);
@@ -145,328 +48,33 @@ static struct class macvtap_class = {
 };
 static struct cdev macvtap_cdev;
 
-static const struct proto_ops macvtap_socket_ops;
-
 #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
                      NETIF_F_TSO6 | NETIF_F_UFO)
-#define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO)
-#define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG | NETIF_F_FRAGLIST)
-
-static struct macvlan_dev *macvtap_get_vlan_rcu(const struct net_device *dev)
-{
-       return rcu_dereference(dev->rx_handler_data);
-}
-
-/*
- * RCU usage:
- * The macvtap_queue and the macvlan_dev are loosely coupled, the
- * pointers from one to the other can only be read while rcu_read_lock
- * or rtnl is held.
- *
- * Both the file and the macvlan_dev hold a reference on the macvtap_queue
- * through sock_hold(&q->sk). When the macvlan_dev goes away first,
- * q->vlan becomes inaccessible. When the files gets closed,
- * macvtap_get_queue() fails.
- *
- * There may still be references to the struct sock inside of the
- * queue from outbound SKBs, but these never reference back to the
- * file or the dev. The data structure is freed through __sk_free
- * when both our references and any pending SKBs are gone.
- */
-
-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;
-
-       ASSERT_RTNL();
-
-       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:
-       return err;
-}
-
-/* Requires RTNL */
-static int macvtap_set_queue(struct net_device *dev, struct file *file,
-                            struct macvtap_queue *q)
-{
-       struct macvlan_dev *vlan = netdev_priv(dev);
-
-       if (vlan->numqueues == MAX_MACVTAP_QUEUES)
-               return -EBUSY;
-
-       rcu_assign_pointer(q->vlan, vlan);
-       rcu_assign_pointer(vlan->taps[vlan->numvtaps], q);
-       sock_hold(&q->sk);
-
-       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++;
-
-       return 0;
-}
-
-static int macvtap_disable_queue(struct macvtap_queue *q)
-{
-       struct macvlan_dev *vlan;
-       struct macvtap_queue *nq;
-
-       ASSERT_RTNL();
-       if (!q->enabled)
-               return -EINVAL;
-
-       vlan = rtnl_dereference(q->vlan);
-
-       if (vlan) {
-               int index = q->queue_index;
-               BUG_ON(index >= vlan->numvtaps);
-               nq = rtnl_dereference(vlan->taps[vlan->numvtaps - 1]);
-               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;
-}
-
-/*
- * The file owning the queue got closed, give up both
- * the reference that the files holds as well as the
- * one from the macvlan_dev if that still exists.
- *
- * Using the spinlock makes sure that we don't get
- * to the queue again after destroying it.
- */
-static void macvtap_put_queue(struct macvtap_queue *q)
-{
-       struct macvlan_dev *vlan;
-
-       rtnl_lock();
-       vlan = rtnl_dereference(q->vlan);
-
-       if (vlan) {
-               if (q->enabled)
-                       BUG_ON(macvtap_disable_queue(q));
-
-               vlan->numqueues--;
-               RCU_INIT_POINTER(q->vlan, NULL);
-               sock_put(&q->sk);
-               list_del_init(&q->next);
-       }
-
-       rtnl_unlock();
-
-       synchronize_rcu();
-       sock_put(&q->sk);
-}
-
-/*
- * Select a queue based on the rxq of the device on which this packet
- * arrived. If the incoming device is not mq, calculate a flow hash
- * to select a queue. If all fails, find the first available queue.
- * Cache vlan->numvtaps since it can become zero during the execution
- * of this function.
- */
-static struct macvtap_queue *macvtap_get_queue(struct net_device *dev,
-                                              struct sk_buff *skb)
-{
-       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;
-
-       if (!numvtaps)
-               goto out;
-
-       if (numvtaps == 1)
-               goto single;
-
-       /* Check if we can use flow to select a queue */
-       rxq = skb_get_hash(skb);
-       if (rxq) {
-               tap = rcu_dereference(vlan->taps[rxq % numvtaps]);
-               goto out;
-       }
-
-       if (likely(skb_rx_queue_recorded(skb))) {
-               rxq = skb_get_rx_queue(skb);
-
-               while (unlikely(rxq >= numvtaps))
-                       rxq -= numvtaps;
 
-               tap = rcu_dereference(vlan->taps[rxq]);
-               goto out;
-       }
-
-single:
-       tap = rcu_dereference(vlan->taps[0]);
-out:
-       return tap;
-}
-
-/*
- * The net_device is going away, give up the reference
- * that it holds on all queues and safely set the pointer
- * from the queues to NULL.
- */
-static void macvtap_del_queues(struct net_device *dev)
+static void macvtap_count_tx_dropped(struct tap_dev *tap)
 {
-       struct macvlan_dev *vlan = netdev_priv(dev);
-       struct macvtap_queue *q, *tmp;
+       struct macvtap_dev *vlantap = container_of(tap, struct macvtap_dev, tap);
+       struct macvlan_dev *vlan = &vlantap->vlan;
 
-       ASSERT_RTNL();
-       list_for_each_entry_safe(q, tmp, &vlan->queue_list, next) {
-               list_del_init(&q->next);
-               RCU_INIT_POINTER(q->vlan, NULL);
-               if (q->enabled)
-                       vlan->numvtaps--;
-               vlan->numqueues--;
-               sock_put(&q->sk);
-       }
-       BUG_ON(vlan->numvtaps);
-       BUG_ON(vlan->numqueues);
-       /* guarantee that any future macvtap_set_queue will fail */
-       vlan->numvtaps = MAX_MACVTAP_QUEUES;
+       this_cpu_inc(vlan->pcpu_stats->tx_dropped);
 }
 
-static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
+static void macvtap_count_rx_dropped(struct tap_dev *tap)
 {
-       struct sk_buff *skb = *pskb;
-       struct net_device *dev = skb->dev;
-       struct macvlan_dev *vlan;
-       struct macvtap_queue *q;
-       netdev_features_t features = TAP_FEATURES;
-
-       vlan = macvtap_get_vlan_rcu(dev);
-       if (!vlan)
-               return RX_HANDLER_PASS;
-
-       q = macvtap_get_queue(dev, skb);
-       if (!q)
-               return RX_HANDLER_PASS;
-
-       if (__skb_array_full(&q->skb_array))
-               goto drop;
-
-       skb_push(skb, ETH_HLEN);
-
-       /* Apply the forward feature mask so that we perform segmentation
-        * according to users wishes.  This only works if VNET_HDR is
-        * enabled.
-        */
-       if (q->flags & IFF_VNET_HDR)
-               features |= vlan->tap_features;
-       if (netif_needs_gso(skb, features)) {
-               struct sk_buff *segs = __skb_gso_segment(skb, features, false);
-
-               if (IS_ERR(segs))
-                       goto drop;
+       struct macvtap_dev *vlantap = container_of(tap, struct macvtap_dev, tap);
+       struct macvlan_dev *vlan = &vlantap->vlan;
 
-               if (!segs) {
-                       if (skb_array_produce(&q->skb_array, skb))
-                               goto drop;
-                       goto wake_up;
-               }
-
-               consume_skb(skb);
-               while (segs) {
-                       struct sk_buff *nskb = segs->next;
-
-                       segs->next = NULL;
-                       if (skb_array_produce(&q->skb_array, segs)) {
-                               kfree_skb(segs);
-                               kfree_skb_list(nskb);
-                               break;
-                       }
-                       segs = nskb;
-               }
-       } else {
-               /* If we receive a partial checksum and the tap side
-                * doesn't support checksum offload, compute the checksum.
-                * Note: it doesn't matter which checksum feature to
-                *        check, we either support them all or none.
-                */
-               if (skb->ip_summed == CHECKSUM_PARTIAL &&
-                   !(features & NETIF_F_CSUM_MASK) &&
-                   skb_checksum_help(skb))
-                       goto drop;
-               if (skb_array_produce(&q->skb_array, skb))
-                       goto drop;
-       }
-
-wake_up:
-       wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND);
-       return RX_HANDLER_CONSUMED;
-
-drop:
-       /* Count errors/drops only here, thus don't care about args. */
        macvlan_count_rx(vlan, 0, 0, 0);
-       kfree_skb(skb);
-       return RX_HANDLER_CONSUMED;
-}
-
-static int macvtap_get_minor(struct macvlan_dev *vlan)
-{
-       int retval = -ENOMEM;
-
-       mutex_lock(&minor_lock);
-       retval = idr_alloc(&minor_idr, vlan, 1, MACVTAP_NUM_DEVS, GFP_KERNEL);
-       if (retval >= 0) {
-               vlan->minor = retval;
-       } else if (retval == -ENOSPC) {
-               netdev_err(vlan->dev, "Too many macvtap devices\n");
-               retval = -EINVAL;
-       }
-       mutex_unlock(&minor_lock);
-       return retval < 0 ? retval : 0;
-}
-
-static void macvtap_free_minor(struct macvlan_dev *vlan)
-{
-       mutex_lock(&minor_lock);
-       if (vlan->minor) {
-               idr_remove(&minor_idr, vlan->minor);
-               vlan->minor = 0;
-       }
-       mutex_unlock(&minor_lock);
 }
 
-static struct net_device *dev_get_by_macvtap_minor(int minor)
+static void macvtap_update_features(struct tap_dev *tap,
+                                   netdev_features_t features)
 {
-       struct net_device *dev = NULL;
-       struct macvlan_dev *vlan;
+       struct macvtap_dev *vlantap = container_of(tap, struct macvtap_dev, tap);
+       struct macvlan_dev *vlan = &vlantap->vlan;
 
-       mutex_lock(&minor_lock);
-       vlan = idr_find(&minor_idr, minor);
-       if (vlan) {
-               dev = vlan->dev;
-               dev_hold(dev);
-       }
-       mutex_unlock(&minor_lock);
-       return dev;
+       vlan->set_features = features;
+       netdev_update_features(vlan->dev);
 }
 
 static int macvtap_newlink(struct net *src_net,
@@ -474,17 +82,24 @@ static int macvtap_newlink(struct net *src_net,
                           struct nlattr *tb[],
                           struct nlattr *data[])
 {
-       struct macvlan_dev *vlan = netdev_priv(dev);
+       struct macvtap_dev *vlantap = netdev_priv(dev);
        int err;
 
-       INIT_LIST_HEAD(&vlan->queue_list);
+       INIT_LIST_HEAD(&vlantap->tap.queue_list);
 
        /* Since macvlan supports all offloads by default, make
         * tap support all offloads also.
         */
-       vlan->tap_features = TUN_OFFLOADS;
+       vlantap->tap.tap_features = TUN_OFFLOADS;
+
+       /* Register callbacks for rx/tx drops accounting and updating
+        * net_device features
+        */
+       vlantap->tap.count_tx_dropped = macvtap_count_tx_dropped;
+       vlantap->tap.count_rx_dropped = macvtap_count_rx_dropped;
+       vlantap->tap.update_features  = macvtap_update_features;
 
-       err = netdev_rx_handler_register(dev, macvtap_handle_frame, vlan);
+       err = netdev_rx_handler_register(dev, tap_handle_frame, &vlantap->tap);
        if (err)
                return err;
 
@@ -497,14 +112,18 @@ static int macvtap_newlink(struct net *src_net,
                return err;
        }
 
+       vlantap->tap.dev = vlantap->vlan.dev;
+
        return 0;
 }
 
 static void macvtap_dellink(struct net_device *dev,
                            struct list_head *head)
 {
+       struct macvtap_dev *vlantap = netdev_priv(dev);
+
        netdev_rx_handler_unregister(dev);
-       macvtap_del_queues(dev);
+       tap_del_queues(&vlantap->tap);
        macvlan_dellink(dev, head);
 }
 
@@ -519,749 +138,14 @@ static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
        .setup          = macvtap_setup,
        .newlink        = macvtap_newlink,
        .dellink        = macvtap_dellink,
+       .priv_size      = sizeof(struct macvtap_dev),
 };
 
-
-static void macvtap_sock_write_space(struct sock *sk)
-{
-       wait_queue_head_t *wqueue;
-
-       if (!sock_writeable(sk) ||
-           !test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
-               return;
-
-       wqueue = sk_sleep(sk);
-       if (wqueue && waitqueue_active(wqueue))
-               wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND);
-}
-
-static void macvtap_sock_destruct(struct sock *sk)
-{
-       struct macvtap_queue *q = container_of(sk, struct macvtap_queue, sk);
-
-       skb_array_cleanup(&q->skb_array);
-}
-
-static int macvtap_open(struct inode *inode, struct file *file)
-{
-       struct net *net = current->nsproxy->net_ns;
-       struct net_device *dev;
-       struct macvtap_queue *q;
-       int err = -ENODEV;
-
-       rtnl_lock();
-       dev = dev_get_by_macvtap_minor(iminor(inode));
-       if (!dev)
-               goto err;
-
-       err = -ENOMEM;
-       q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
-                                            &macvtap_proto, 0);
-       if (!q)
-               goto err;
-
-       RCU_INIT_POINTER(q->sock.wq, &q->wq);
-       init_waitqueue_head(&q->wq.wait);
-       q->sock.type = SOCK_RAW;
-       q->sock.state = SS_CONNECTED;
-       q->sock.file = file;
-       q->sock.ops = &macvtap_socket_ops;
-       sock_init_data(&q->sock, &q->sk);
-       q->sk.sk_write_space = macvtap_sock_write_space;
-       q->sk.sk_destruct = macvtap_sock_destruct;
-       q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
-       q->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
-
-       /*
-        * so far only KVM virtio_net uses macvtap, enable zero copy between
-        * guest kernel and host kernel when lower device supports zerocopy
-        *
-        * The macvlan supports zerocopy iff the lower device supports zero
-        * copy so we don't have to look at the lower device directly.
-        */
-       if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG))
-               sock_set_flag(&q->sk, SOCK_ZEROCOPY);
-
-       err = -ENOMEM;
-       if (skb_array_init(&q->skb_array, dev->tx_queue_len, GFP_KERNEL))
-               goto err_array;
-
-       err = macvtap_set_queue(dev, file, q);
-       if (err)
-               goto err_queue;
-
-       dev_put(dev);
-
-       rtnl_unlock();
-       return err;
-
-err_queue:
-       skb_array_cleanup(&q->skb_array);
-err_array:
-       sock_put(&q->sk);
-err:
-       if (dev)
-               dev_put(dev);
-
-       rtnl_unlock();
-       return err;
-}
-
-static int macvtap_release(struct inode *inode, struct file *file)
-{
-       struct macvtap_queue *q = file->private_data;
-       macvtap_put_queue(q);
-       return 0;
-}
-
-static unsigned int macvtap_poll(struct file *file, poll_table * wait)
-{
-       struct macvtap_queue *q = file->private_data;
-       unsigned int mask = POLLERR;
-
-       if (!q)
-               goto out;
-
-       mask = 0;
-       poll_wait(file, &q->wq.wait, wait);
-
-       if (!skb_array_empty(&q->skb_array))
-               mask |= POLLIN | POLLRDNORM;
-
-       if (sock_writeable(&q->sk) ||
-           (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &q->sock.flags) &&
-            sock_writeable(&q->sk)))
-               mask |= POLLOUT | POLLWRNORM;
-
-out:
-       return mask;
-}
-
-static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad,
-                                               size_t len, size_t linear,
-                                               int noblock, int *err)
-{
-       struct sk_buff *skb;
-
-       /* Under a page?  Don't bother with paged skb. */
-       if (prepad + len < PAGE_SIZE || !linear)
-               linear = len;
-
-       skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
-                                  err, 0);
-       if (!skb)
-               return NULL;
-
-       skb_reserve(skb, prepad);
-       skb_put(skb, linear);
-       skb->data_len = len - linear;
-       skb->len += len - linear;
-
-       return skb;
-}
-
-/* Neighbour code has some assumptions on HH_DATA_MOD alignment */
-#define MACVTAP_RESERVE HH_DATA_OFF(ETH_HLEN)
-
-/* Get packet from user space buffer */
-static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
-                               struct iov_iter *from, int noblock)
-{
-       int good_linear = SKB_MAX_HEAD(MACVTAP_RESERVE);
-       struct sk_buff *skb;
-       struct macvlan_dev *vlan;
-       unsigned long total_len = iov_iter_count(from);
-       unsigned long len = total_len;
-       int err;
-       struct virtio_net_hdr vnet_hdr = { 0 };
-       int vnet_hdr_len = 0;
-       int copylen = 0;
-       int depth;
-       bool zerocopy = false;
-       size_t linear;
-
-       if (q->flags & IFF_VNET_HDR) {
-               vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
-
-               err = -EINVAL;
-               if (len < vnet_hdr_len)
-                       goto err;
-               len -= vnet_hdr_len;
-
-               err = -EFAULT;
-               if (!copy_from_iter_full(&vnet_hdr, sizeof(vnet_hdr), from))
-                       goto err;
-               iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr));
-               if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
-                    macvtap16_to_cpu(q, vnet_hdr.csum_start) +
-                    macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2 >
-                            macvtap16_to_cpu(q, vnet_hdr.hdr_len))
-                       vnet_hdr.hdr_len = cpu_to_macvtap16(q,
-                                macvtap16_to_cpu(q, vnet_hdr.csum_start) +
-                                macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2);
-               err = -EINVAL;
-               if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > len)
-                       goto err;
-       }
-
-       err = -EINVAL;
-       if (unlikely(len < ETH_HLEN))
-               goto err;
-
-       if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) {
-               struct iov_iter i;
-
-               copylen = vnet_hdr.hdr_len ?
-                       macvtap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN;
-               if (copylen > good_linear)
-                       copylen = good_linear;
-               else if (copylen < ETH_HLEN)
-                       copylen = ETH_HLEN;
-               linear = copylen;
-               i = *from;
-               iov_iter_advance(&i, copylen);
-               if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
-                       zerocopy = true;
-       }
-
-       if (!zerocopy) {
-               copylen = len;
-               linear = macvtap16_to_cpu(q, vnet_hdr.hdr_len);
-               if (linear > good_linear)
-                       linear = good_linear;
-               else if (linear < ETH_HLEN)
-                       linear = ETH_HLEN;
-       }
-
-       skb = macvtap_alloc_skb(&q->sk, MACVTAP_RESERVE, copylen,
-                               linear, noblock, &err);
-       if (!skb)
-               goto err;
-
-       if (zerocopy)
-               err = zerocopy_sg_from_iter(skb, from);
-       else
-               err = skb_copy_datagram_from_iter(skb, 0, from, len);
-
-       if (err)
-               goto err_kfree;
-
-       skb_set_network_header(skb, ETH_HLEN);
-       skb_reset_mac_header(skb);
-       skb->protocol = eth_hdr(skb)->h_proto;
-
-       if (vnet_hdr_len) {
-               err = virtio_net_hdr_to_skb(skb, &vnet_hdr,
-                                           macvtap_is_little_endian(q));
-               if (err)
-                       goto err_kfree;
-       }
-
-       skb_probe_transport_header(skb, ETH_HLEN);
-
-       /* Move network header to the right position for VLAN tagged packets */
-       if ((skb->protocol == htons(ETH_P_8021Q) ||
-            skb->protocol == htons(ETH_P_8021AD)) &&
-           __vlan_get_protocol(skb, skb->protocol, &depth) != 0)
-               skb_set_network_header(skb, depth);
-
-       rcu_read_lock();
-       vlan = rcu_dereference(q->vlan);
-       /* copy skb_ubuf_info for callback when skb has no error */
-       if (zerocopy) {
-               skb_shinfo(skb)->destructor_arg = m->msg_control;
-               skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
-               skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
-       } else if (m && m->msg_control) {
-               struct ubuf_info *uarg = m->msg_control;
-               uarg->callback(uarg, false);
-       }
-
-       if (vlan) {
-               skb->dev = vlan->dev;
-               dev_queue_xmit(skb);
-       } else {
-               kfree_skb(skb);
-       }
-       rcu_read_unlock();
-
-       return total_len;
-
-err_kfree:
-       kfree_skb(skb);
-
-err:
-       rcu_read_lock();
-       vlan = rcu_dereference(q->vlan);
-       if (vlan)
-               this_cpu_inc(vlan->pcpu_stats->tx_dropped);
-       rcu_read_unlock();
-
-       return err;
-}
-
-static ssize_t macvtap_write_iter(struct kiocb *iocb, struct iov_iter *from)
-{
-       struct file *file = iocb->ki_filp;
-       struct macvtap_queue *q = file->private_data;
-
-       return macvtap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK);
-}
-
-/* Put packet to the user space buffer */
-static ssize_t macvtap_put_user(struct macvtap_queue *q,
-                               const struct sk_buff *skb,
-                               struct iov_iter *iter)
-{
-       int ret;
-       int vnet_hdr_len = 0;
-       int vlan_offset = 0;
-       int total;
-
-       if (q->flags & IFF_VNET_HDR) {
-               struct virtio_net_hdr vnet_hdr;
-               vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
-               if (iov_iter_count(iter) < vnet_hdr_len)
-                       return -EINVAL;
-
-               if (virtio_net_hdr_from_skb(skb, &vnet_hdr,
-                                           macvtap_is_little_endian(q), true))
-                       BUG();
-
-               if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) !=
-                   sizeof(vnet_hdr))
-                       return -EFAULT;
-
-               iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr));
-       }
-       total = vnet_hdr_len;
-       total += skb->len;
-
-       if (skb_vlan_tag_present(skb)) {
-               struct {
-                       __be16 h_vlan_proto;
-                       __be16 h_vlan_TCI;
-               } veth;
-               veth.h_vlan_proto = skb->vlan_proto;
-               veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
-
-               vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
-               total += VLAN_HLEN;
-
-               ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
-               if (ret || !iov_iter_count(iter))
-                       goto done;
-
-               ret = copy_to_iter(&veth, sizeof(veth), iter);
-               if (ret != sizeof(veth) || !iov_iter_count(iter))
-                       goto done;
-       }
-
-       ret = skb_copy_datagram_iter(skb, vlan_offset, iter,
-                                    skb->len - vlan_offset);
-
-done:
-       return ret ? ret : total;
-}
-
-static ssize_t macvtap_do_read(struct macvtap_queue *q,
-                              struct iov_iter *to,
-                              int noblock)
-{
-       DEFINE_WAIT(wait);
-       struct sk_buff *skb;
-       ssize_t ret = 0;
-
-       if (!iov_iter_count(to))
-               return 0;
-
-       while (1) {
-               if (!noblock)
-                       prepare_to_wait(sk_sleep(&q->sk), &wait,
-                                       TASK_INTERRUPTIBLE);
-
-               /* Read frames from the queue */
-               skb = skb_array_consume(&q->skb_array);
-               if (skb)
-                       break;
-               if (noblock) {
-                       ret = -EAGAIN;
-                       break;
-               }
-               if (signal_pending(current)) {
-                       ret = -ERESTARTSYS;
-                       break;
-               }
-               /* Nothing to read, let's sleep */
-               schedule();
-       }
-       if (!noblock)
-               finish_wait(sk_sleep(&q->sk), &wait);
-
-       if (skb) {
-               ret = macvtap_put_user(q, skb, to);
-               if (unlikely(ret < 0))
-                       kfree_skb(skb);
-               else
-                       consume_skb(skb);
-       }
-       return ret;
-}
-
-static ssize_t macvtap_read_iter(struct kiocb *iocb, struct iov_iter *to)
-{
-       struct file *file = iocb->ki_filp;
-       struct macvtap_queue *q = file->private_data;
-       ssize_t len = iov_iter_count(to), ret;
-
-       ret = macvtap_do_read(q, to, file->f_flags & O_NONBLOCK);
-       ret = min_t(ssize_t, ret, len);
-       if (ret > 0)
-               iocb->ki_pos = ret;
-       return ret;
-}
-
-static struct macvlan_dev *macvtap_get_vlan(struct macvtap_queue *q)
-{
-       struct macvlan_dev *vlan;
-
-       ASSERT_RTNL();
-       vlan = rtnl_dereference(q->vlan);
-       if (vlan)
-               dev_hold(vlan->dev);
-
-       return vlan;
-}
-
-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);
-       else
-               ret = -EINVAL;
-
-       macvtap_put_vlan(vlan);
-       return ret;
-}
-
-static int set_offload(struct macvtap_queue *q, unsigned long arg)
-{
-       struct macvlan_dev *vlan;
-       netdev_features_t features;
-       netdev_features_t feature_mask = 0;
-
-       vlan = rtnl_dereference(q->vlan);
-       if (!vlan)
-               return -ENOLINK;
-
-       features = vlan->dev->features;
-
-       if (arg & TUN_F_CSUM) {
-               feature_mask = NETIF_F_HW_CSUM;
-
-               if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) {
-                       if (arg & TUN_F_TSO_ECN)
-                               feature_mask |= NETIF_F_TSO_ECN;
-                       if (arg & TUN_F_TSO4)
-                               feature_mask |= NETIF_F_TSO;
-                       if (arg & TUN_F_TSO6)
-                               feature_mask |= NETIF_F_TSO6;
-               }
-
-               if (arg & TUN_F_UFO)
-                       feature_mask |= NETIF_F_UFO;
-       }
-
-       /* tun/tap driver inverts the usage for TSO offloads, where
-        * setting the TSO bit means that the userspace wants to
-        * accept TSO frames and turning it off means that user space
-        * does not support TSO.
-        * For macvtap, we have to invert it to mean the same thing.
-        * When user space turns off TSO, we turn off GSO/LRO so that
-        * user-space will not receive TSO frames.
-        */
-       if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO))
-               features |= RX_OFFLOADS;
-       else
-               features &= ~RX_OFFLOADS;
-
-       /* tap_features are the same as features on tun/tap and
-        * reflect user expectations.
-        */
-       vlan->tap_features = feature_mask;
-       vlan->set_features = features;
-       netdev_update_features(vlan->dev);
-
-       return 0;
-}
-
-/*
- * provide compatibility with generic tun/tap interface
- */
-static long macvtap_ioctl(struct file *file, unsigned int cmd,
-                         unsigned long arg)
-{
-       struct macvtap_queue *q = file->private_data;
-       struct macvlan_dev *vlan;
-       void __user *argp = (void __user *)arg;
-       struct ifreq __user *ifr = argp;
-       unsigned int __user *up = argp;
-       unsigned short u;
-       int __user *sp = argp;
-       struct sockaddr sa;
-       int s;
-       int ret;
-
-       switch (cmd) {
-       case TUNSETIFF:
-               /* ignore the name, just look at flags */
-               if (get_user(u, &ifr->ifr_flags))
-                       return -EFAULT;
-
-               ret = 0;
-               if ((u & ~MACVTAP_FEATURES) != (IFF_NO_PI | IFF_TAP))
-                       ret = -EINVAL;
-               else
-                       q->flags = (q->flags & ~MACVTAP_FEATURES) | u;
-
-               return ret;
-
-       case TUNGETIFF:
-               rtnl_lock();
-               vlan = macvtap_get_vlan(q);
-               if (!vlan) {
-                       rtnl_unlock();
-                       return -ENOLINK;
-               }
-
-               ret = 0;
-               u = q->flags;
-               if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
-                   put_user(u, &ifr->ifr_flags))
-                       ret = -EFAULT;
-               macvtap_put_vlan(vlan);
-               rtnl_unlock();
-               return ret;
-
-       case TUNSETQUEUE:
-               if (get_user(u, &ifr->ifr_flags))
-                       return -EFAULT;
-               rtnl_lock();
-               ret = macvtap_ioctl_set_queue(file, u);
-               rtnl_unlock();
-               return ret;
-
-       case TUNGETFEATURES:
-               if (put_user(IFF_TAP | IFF_NO_PI | MACVTAP_FEATURES, up))
-                       return -EFAULT;
-               return 0;
-
-       case TUNSETSNDBUF:
-               if (get_user(s, sp))
-                       return -EFAULT;
-
-               q->sk.sk_sndbuf = s;
-               return 0;
-
-       case TUNGETVNETHDRSZ:
-               s = q->vnet_hdr_sz;
-               if (put_user(s, sp))
-                       return -EFAULT;
-               return 0;
-
-       case TUNSETVNETHDRSZ:
-               if (get_user(s, sp))
-                       return -EFAULT;
-               if (s < (int)sizeof(struct virtio_net_hdr))
-                       return -EINVAL;
-
-               q->vnet_hdr_sz = s;
-               return 0;
-
-       case TUNGETVNETLE:
-               s = !!(q->flags & MACVTAP_VNET_LE);
-               if (put_user(s, sp))
-                       return -EFAULT;
-               return 0;
-
-       case TUNSETVNETLE:
-               if (get_user(s, sp))
-                       return -EFAULT;
-               if (s)
-                       q->flags |= MACVTAP_VNET_LE;
-               else
-                       q->flags &= ~MACVTAP_VNET_LE;
-               return 0;
-
-       case TUNGETVNETBE:
-               return macvtap_get_vnet_be(q, sp);
-
-       case TUNSETVNETBE:
-               return macvtap_set_vnet_be(q, sp);
-
-       case TUNSETOFFLOAD:
-               /* let the user check for future flags */
-               if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
-                           TUN_F_TSO_ECN | TUN_F_UFO))
-                       return -EINVAL;
-
-               rtnl_lock();
-               ret = set_offload(q, arg);
-               rtnl_unlock();
-               return ret;
-
-       case SIOCGIFHWADDR:
-               rtnl_lock();
-               vlan = macvtap_get_vlan(q);
-               if (!vlan) {
-                       rtnl_unlock();
-                       return -ENOLINK;
-               }
-               ret = 0;
-               u = vlan->dev->type;
-               if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
-                   copy_to_user(&ifr->ifr_hwaddr.sa_data, vlan->dev->dev_addr, ETH_ALEN) ||
-                   put_user(u, &ifr->ifr_hwaddr.sa_family))
-                       ret = -EFAULT;
-               macvtap_put_vlan(vlan);
-               rtnl_unlock();
-               return ret;
-
-       case SIOCSIFHWADDR:
-               if (copy_from_user(&sa, &ifr->ifr_hwaddr, sizeof(sa)))
-                       return -EFAULT;
-               rtnl_lock();
-               vlan = macvtap_get_vlan(q);
-               if (!vlan) {
-                       rtnl_unlock();
-                       return -ENOLINK;
-               }
-               ret = dev_set_mac_address(vlan->dev, &sa);
-               macvtap_put_vlan(vlan);
-               rtnl_unlock();
-               return ret;
-
-       default:
-               return -EINVAL;
-       }
-}
-
-#ifdef CONFIG_COMPAT
-static long macvtap_compat_ioctl(struct file *file, unsigned int cmd,
-                                unsigned long arg)
-{
-       return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
-}
-#endif
-
-static const struct file_operations macvtap_fops = {
-       .owner          = THIS_MODULE,
-       .open           = macvtap_open,
-       .release        = macvtap_release,
-       .read_iter      = macvtap_read_iter,
-       .write_iter     = macvtap_write_iter,
-       .poll           = macvtap_poll,
-       .llseek         = no_llseek,
-       .unlocked_ioctl = macvtap_ioctl,
-#ifdef CONFIG_COMPAT
-       .compat_ioctl   = macvtap_compat_ioctl,
-#endif
-};
-
-static int macvtap_sendmsg(struct socket *sock, struct msghdr *m,
-                          size_t total_len)
-{
-       struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
-       return macvtap_get_user(q, m, &m->msg_iter, m->msg_flags & MSG_DONTWAIT);
-}
-
-static int macvtap_recvmsg(struct socket *sock, struct msghdr *m,
-                          size_t total_len, int flags)
-{
-       struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
-       int ret;
-       if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
-               return -EINVAL;
-       ret = macvtap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT);
-       if (ret > total_len) {
-               m->msg_flags |= MSG_TRUNC;
-               ret = flags & MSG_TRUNC ? ret : total_len;
-       }
-       return ret;
-}
-
-static int macvtap_peek_len(struct socket *sock)
-{
-       struct macvtap_queue *q = container_of(sock, struct macvtap_queue,
-                                              sock);
-       return skb_array_peek_len(&q->skb_array);
-}
-
-/* Ops structure to mimic raw sockets with tun */
-static const struct proto_ops macvtap_socket_ops = {
-       .sendmsg = macvtap_sendmsg,
-       .recvmsg = macvtap_recvmsg,
-       .peek_len = macvtap_peek_len,
-};
-
-/* Get an underlying socket object from tun file.  Returns error unless file is
- * attached to a device.  The returned object works like a packet socket, it
- * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
- * holding a reference to the file for as long as the socket is in use. */
-struct socket *macvtap_get_socket(struct file *file)
-{
-       struct macvtap_queue *q;
-       if (file->f_op != &macvtap_fops)
-               return ERR_PTR(-EINVAL);
-       q = file->private_data;
-       if (!q)
-               return ERR_PTR(-EBADFD);
-       return &q->sock;
-}
-EXPORT_SYMBOL_GPL(macvtap_get_socket);
-
-static int macvtap_queue_resize(struct macvlan_dev *vlan)
-{
-       struct net_device *dev = vlan->dev;
-       struct macvtap_queue *q;
-       struct skb_array **arrays;
-       int n = vlan->numqueues;
-       int ret, i = 0;
-
-       arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL);
-       if (!arrays)
-               return -ENOMEM;
-
-       list_for_each_entry(q, &vlan->queue_list, next)
-               arrays[i++] = &q->skb_array;
-
-       ret = skb_array_resize_multiple(arrays, n,
-                                       dev->tx_queue_len, GFP_KERNEL);
-
-       kfree(arrays);
-       return ret;
-}
-
 static int macvtap_device_event(struct notifier_block *unused,
                                unsigned long event, void *ptr)
 {
        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
-       struct macvlan_dev *vlan;
+       struct macvtap_dev *vlantap;
        struct device *classdev;
        dev_t devt;
        int err;
@@ -1271,7 +155,7 @@ static int macvtap_device_event(struct notifier_block *unused,
                return NOTIFY_DONE;
 
        snprintf(tap_name, IFNAMSIZ, "tap%d", dev->ifindex);
-       vlan = netdev_priv(dev);
+       vlantap = netdev_priv(dev);
 
        switch (event) {
        case NETDEV_REGISTER:
@@ -1279,15 +163,15 @@ static int macvtap_device_event(struct notifier_block *unused,
                 * been registered but before register_netdevice has
                 * finished running.
                 */
-               err = macvtap_get_minor(vlan);
+               err = tap_get_minor(macvtap_major, &vlantap->tap);
                if (err)
                        return notifier_from_errno(err);
 
-               devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
+               devt = MKDEV(MAJOR(macvtap_major), vlantap->tap.minor);
                classdev = device_create(&macvtap_class, &dev->dev, devt,
                                         dev, tap_name);
                if (IS_ERR(classdev)) {
-                       macvtap_free_minor(vlan);
+                       tap_free_minor(macvtap_major, &vlantap->tap);
                        return notifier_from_errno(PTR_ERR(classdev));
                }
                err = sysfs_create_link(&dev->dev.kobj, &classdev->kobj,
@@ -1297,15 +181,15 @@ static int macvtap_device_event(struct notifier_block *unused,
                break;
        case NETDEV_UNREGISTER:
                /* vlan->minor == 0 if NETDEV_REGISTER above failed */
-               if (vlan->minor == 0)
+               if (vlantap->tap.minor == 0)
                        break;
                sysfs_remove_link(&dev->dev.kobj, tap_name);
-               devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
+               devt = MKDEV(MAJOR(macvtap_major), vlantap->tap.minor);
                device_destroy(&macvtap_class, devt);
-               macvtap_free_minor(vlan);
+               tap_free_minor(macvtap_major, &vlantap->tap);
                break;
        case NETDEV_CHANGE_TX_QUEUE_LEN:
-               if (macvtap_queue_resize(vlan))
+               if (tap_queue_resize(&vlantap->tap))
                        return NOTIFY_BAD;
                break;
        }
@@ -1321,38 +205,31 @@ static int macvtap_init(void)
 {
        int err;
 
-       err = alloc_chrdev_region(&macvtap_major, 0,
-                               MACVTAP_NUM_DEVS, "macvtap");
-       if (err)
-               goto out1;
+       err = tap_create_cdev(&macvtap_cdev, &macvtap_major, "macvtap");
 
-       cdev_init(&macvtap_cdev, &macvtap_fops);
-       err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);
        if (err)
-               goto out2;
+               goto out1;
 
        err = class_register(&macvtap_class);
        if (err)
-               goto out3;
+               goto out2;
 
        err = register_netdevice_notifier(&macvtap_notifier_block);
        if (err)
-               goto out4;
+               goto out3;
 
        err = macvlan_link_register(&macvtap_link_ops);
        if (err)
-               goto out5;
+               goto out4;
 
        return 0;
 
-out5:
-       unregister_netdevice_notifier(&macvtap_notifier_block);
 out4:
-       class_unregister(&macvtap_class);
+       unregister_netdevice_notifier(&macvtap_notifier_block);
 out3:
-       cdev_del(&macvtap_cdev);
+       class_unregister(&macvtap_class);
 out2:
-       unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
+       tap_destroy_cdev(macvtap_major, &macvtap_cdev);
 out1:
        return err;
 }
@@ -1363,9 +240,7 @@ static void macvtap_exit(void)
        rtnl_link_unregister(&macvtap_link_ops);
        unregister_netdevice_notifier(&macvtap_notifier_block);
        class_unregister(&macvtap_class);
-       cdev_del(&macvtap_cdev);
-       unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
-       idr_destroy(&minor_idr);
+       tap_destroy_cdev(macvtap_major, &macvtap_cdev);
 }
 module_exit(macvtap_exit);