netdev - Re: [bpf-next V2 PATCH 4/8] tun: implement flush flag for ndo_xdp

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Message-ID: <CAPhsuW4vW4RjT4dTT+GgPGePA1wVpmbRD9ZmV3yrMMKN5_TX2g@mail.gmail.com>
Date:   Thu, 31 May 2018 09:14:53 -0700
From:   Song Liu <liu.song.a23@...il.com>
To:     Jesper Dangaard Brouer <brouer@...hat.com>
Cc:     Networking <netdev@...r.kernel.org>,
        Daniel Borkmann <borkmann@...earbox.net>,
        Alexei Starovoitov <alexei.starovoitov@...il.com>,
        Song Liu <songliubraving@...com>,
        John Fastabend <john.fastabend@...il.com>
Subject: Re: [bpf-next V2 PATCH 4/8] tun: implement flush flag for ndo_xdp_xmit

On Thu, May 31, 2018 at 2:00 AM, Jesper Dangaard Brouer
<brouer@...hat.com> wrote:
> When passed the XDP_XMIT_FLUSH flag tun_xdp_xmit now performs the same
> kind of socket wake up as in tun_xdp_flush(). The wake up code from
> tun_xdp_flush is generalized and shared with tun_xdp_xmit.
>
> Signed-off-by: Jesper Dangaard Brouer <brouer@...hat.com>

Acked-by: Song Liu <songliubraving@...com>

> ---
>  drivers/net/tun.c |   19 +++++++++++++------
>  1 file changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index b182b8cdd219..d82a05fb0594 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -1285,6 +1285,14 @@ static const struct net_device_ops tun_netdev_ops = {
>         .ndo_get_stats64        = tun_net_get_stats64,
>  };
>
> +static void __tun_xdp_flush_tfile(struct tun_file *tfile)
> +{
> +       /* Notify and wake up reader process */
> +       if (tfile->flags & TUN_FASYNC)
> +               kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
> +       tfile->socket.sk->sk_data_ready(tfile->socket.sk);
> +}
> +
>  static int tun_xdp_xmit(struct net_device *dev, int n,
>                         struct xdp_frame **frames, u32 flags)
>  {
> @@ -1295,7 +1303,7 @@ static int tun_xdp_xmit(struct net_device *dev, int n,
>         int cnt = n;
>         int i;
>
> -       if (unlikely(flags & ~XDP_XMIT_FLAGS_NONE))
> +       if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
>                 return -EINVAL;
>
>         rcu_read_lock();
> @@ -1325,6 +1333,9 @@ static int tun_xdp_xmit(struct net_device *dev, int n,
>         }
>         spin_unlock(&tfile->tx_ring.producer_lock);
>
> +       if (flags & XDP_XMIT_FLUSH)
> +               __tun_xdp_flush_tfile(tfile);
> +
>         rcu_read_unlock();
>         return cnt - drops;
>  }
> @@ -1353,11 +1364,7 @@ static void tun_xdp_flush(struct net_device *dev)
>
>         tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
>                                             numqueues]);
> -       /* Notify and wake up reader process */
> -       if (tfile->flags & TUN_FASYNC)
> -               kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
> -       tfile->socket.sk->sk_data_ready(tfile->socket.sk);
> -
> +       __tun_xdp_flush_tfile(tfile);
>  out:
>         rcu_read_unlock();
>  }
>