On Thu, Mar 30, 2017 at 03:22:29PM +0800, Jason Wang wrote:
> This patch makes tap_recvmsg() can receive from skb from its caller
> through msg_control. Vhost_net will be the first user.
>
> Signed-off-by: Jason Wang <jasow...@redhat.com>
> ---
> drivers/net/tap.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/tap.c b/drivers/net/tap.c
> index abdaf86..07d9174 100644
> --- a/drivers/net/tap.c
> +++ b/drivers/net/tap.c
> @@ -824,15 +824,17 @@ static ssize_t tap_put_user(struct tap_queue *q,
>
> static ssize_t tap_do_read(struct tap_queue *q,
> struct iov_iter *to,
> - int noblock)
> + int noblock, struct sk_buff *skb)
> {
> DEFINE_WAIT(wait);
> - struct sk_buff *skb;
> ssize_t ret = 0;
>
> if (!iov_iter_count(to))
> return 0;
>
> + if (skb)
> + goto done;
> +
> while (1) {
> if (!noblock)
> prepare_to_wait(sk_sleep(&q->sk), &wait,
> @@ -856,6 +858,7 @@ static ssize_t tap_do_read(struct tap_queue *q,
> if (!noblock)
> finish_wait(sk_sleep(&q->sk), &wait);
>
> +done:
Please just use an if {} block here. goto on error is ok,
but we are far from done here and goto done is misleading.
> if (skb) {
> ret = tap_put_user(q, skb, to);
> if (unlikely(ret < 0))
> @@ -872,7 +875,7 @@ static ssize_t tap_read_iter(struct kiocb *iocb, struct
> iov_iter *to)
> struct tap_queue *q = file->private_data;
> ssize_t len = iov_iter_count(to), ret;
>
> - ret = tap_do_read(q, to, file->f_flags & O_NONBLOCK);
> + ret = tap_do_read(q, to, file->f_flags & O_NONBLOCK, NULL);
> ret = min_t(ssize_t, ret, len);
> if (ret > 0)
> iocb->ki_pos = ret;
> @@ -1155,7 +1158,8 @@ static int tap_recvmsg(struct socket *sock, struct
> msghdr *m,
> int ret;
> if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
> return -EINVAL;
> - ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT);
> + ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT,
> + m->msg_control);
> if (ret > total_len) {
> m->msg_flags |= MSG_TRUNC;
> ret = flags & MSG_TRUNC ? ret : total_len;
> --
> 2.7.4
