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Subject[PATCH 2/2] net/macvtap: add vhost support
Date
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);
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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