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SubjectRe: [PATCH 2/2] net/macvtap: add vhost support
On Sat, Feb 13, 2010 at 11:35:08AM +0100, Arnd Bergmann wrote:
> This adds support for passing a macvtap file descriptor into
> vhost-net, much like we already do for tun/tap.
>
> Most of the new code is taken from the respective patch
> in the tun driver and may get consolidated in the future.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/net/macvtap.c | 98 ++++++++++++++++++++++++++++++++++---------
> drivers/vhost/net.c | 8 +++-
> include/linux/if_macvlan.h | 13 ++++++
> 3 files changed, 96 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
> index 7050997..e354501 100644
> --- a/drivers/net/macvtap.c
> +++ b/drivers/net/macvtap.c
> @@ -58,6 +58,8 @@ static unsigned int macvtap_major;
> static struct class *macvtap_class;
> static struct cdev macvtap_cdev;
>
> +static const struct proto_ops macvtap_socket_ops;
> +
> /*
> * RCU usage:
> * The macvtap_queue and the macvlan_dev are loosely coupled, the
> @@ -176,7 +178,7 @@ static int macvtap_forward(struct net_device *dev, struct sk_buff *skb)
> return -ENOLINK;
>
> skb_queue_tail(&q->sk.sk_receive_queue, skb);
> - wake_up(q->sk.sk_sleep);
> + wake_up_interruptible_poll(q->sk.sk_sleep, POLLIN | POLLRDNORM | POLLRDBAND);
> return 0;
> }
>
> @@ -242,7 +244,7 @@ static void macvtap_sock_write_space(struct sock *sk)
> return;
>
> if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
> - wake_up_interruptible_sync(sk->sk_sleep);
> + wake_up_interruptible_poll(sk->sk_sleep, POLLOUT | POLLWRNORM | POLLWRBAND);
> }
>
> static int macvtap_open(struct inode *inode, struct file *file)
> @@ -270,6 +272,8 @@ static int macvtap_open(struct inode *inode, struct file *file)
> init_waitqueue_head(&q->sock.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;
>
> @@ -387,32 +391,20 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q,
>
> rcu_read_lock_bh();
> vlan = rcu_dereference(q->vlan);
> - macvlan_count_rx(vlan, len, ret == 0, 0);
> + if (vlan)
> + macvlan_count_rx(vlan, len, ret == 0, 0);
> rcu_read_unlock_bh();
>
> return ret ? ret : len;
> }
>
> -static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
> - unsigned long count, loff_t pos)
> +static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb,
> + const struct iovec *iv, unsigned long len,
> + int noblock)
> {
> - struct file *file = iocb->ki_filp;
> - struct macvtap_queue *q = file->private_data;
> -
> DECLARE_WAITQUEUE(wait, current);
> struct sk_buff *skb;
> - ssize_t len, ret = 0;
> -
> - if (!q) {
> - ret = -ENOLINK;
> - goto out;
> - }
> -
> - len = iov_length(iv, count);
> - if (len < 0) {
> - ret = -EINVAL;
> - goto out;
> - }
> + ssize_t ret = 0;
>
> add_wait_queue(q->sk.sk_sleep, &wait);
> while (len) {
> @@ -421,7 +413,7 @@ static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
> /* Read frames from the queue */
> skb = skb_dequeue(&q->sk.sk_receive_queue);
> if (!skb) {
> - if (file->f_flags & O_NONBLOCK) {
> + if (noblock) {
> ret = -EAGAIN;
> break;
> }
> @@ -440,7 +432,24 @@ static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
>
> current->state = TASK_RUNNING;
> remove_wait_queue(q->sk.sk_sleep, &wait);
> + return ret;
> +}
> +
> +static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
> + unsigned long count, loff_t pos)
> +{
> + struct file *file = iocb->ki_filp;
> + struct macvtap_queue *q = file->private_data;
> + ssize_t len, ret = 0;
>
> + len = iov_length(iv, count);
> + if (len < 0) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + ret = macvtap_do_read(q, iocb, iv, len, file->f_flags & O_NONBLOCK);
> + ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */
> out:
> return ret;
> }
> @@ -538,6 +547,53 @@ static const struct file_operations macvtap_fops = {
> #endif
> };
>
> +static int macvtap_sendmsg(struct kiocb *iocb, 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->msg_iov, total_len,
> + m->msg_flags & MSG_DONTWAIT);
> +}
> +
> +static int macvtap_recvmsg(struct kiocb *iocb, 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, iocb, m->msg_iov, total_len,
> + flags & MSG_DONTWAIT);
> + if (ret > total_len) {
> + m->msg_flags |= MSG_TRUNC;
> + ret = flags & MSG_TRUNC ? ret : total_len;
> + }
> + return ret;
> +}
> +
> +/* Ops structure to mimic raw sockets with tun */
> +static const struct proto_ops macvtap_socket_ops = {
> + .sendmsg = macvtap_sendmsg,
> + .recvmsg = macvtap_recvmsg,
> +};
> +
> +/* 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_init(void)
> {
> int err;
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 4c89283..91a324c 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -22,6 +22,7 @@
> #include <linux/if_packet.h>
> #include <linux/if_arp.h>
> #include <linux/if_tun.h>
> +#include <linux/if_macvlan.h>
>
> #include <net/sock.h>
>
> @@ -452,13 +453,16 @@ err:
> return ERR_PTR(r);
> }
>
> -static struct socket *get_tun_socket(int fd)
> +static struct socket *get_tap_socket(int fd)
> {
> struct file *file = fget(fd);
> struct socket *sock;
> if (!file)
> return ERR_PTR(-EBADF);
> sock = tun_get_socket(file);
> + if (!IS_ERR(sock))
> + return sock;
> + sock = macvtap_get_socket(file);
> if (IS_ERR(sock))
> fput(file);
> return sock;
> @@ -473,7 +477,7 @@ static struct socket *get_socket(int fd)
> sock = get_raw_socket(fd);
> if (!IS_ERR(sock))
> return sock;
> - sock = get_tun_socket(fd);
> + sock = get_tap_socket(fd);
> if (!IS_ERR(sock))
> return sock;
> return ERR_PTR(-ENOTSOCK);

This will also need a dependency on macvtap in Kconfig.
See how it's done for tun.

> diff --git a/include/linux/if_macvlan.h b/include/linux/if_macvlan.h
> index 51f1512..7d7f1e3 100644
> --- a/include/linux/if_macvlan.h
> +++ b/include/linux/if_macvlan.h
> @@ -7,6 +7,19 @@
> #include <linux/netlink.h>
> #include <net/netlink.h>
>
> +#if defined(CONFIG_MACVTAP) || defined(CONFIG_MACVTAP_MODULE)
> +struct socket *macvtap_get_socket(struct file *);
> +#else
> +#include <linux/err.h>
> +#include <linux/errno.h>
> +struct file;
> +struct socket;
> +static inline struct socket *macvtap_get_socket(struct file *f)
> +{
> + return ERR_PTR(-EINVAL);
> +}
> +#endif /* CONFIG_MACVTAP */
> +
> struct macvlan_port;
> struct macvtap_queue;
>
> --
> 1.6.3.3
>
> --
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