netdev - Re: [bpf-next V2 PATCH 3/8] ixgbe: implement flush flag for ndo_xdp

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAPhsuW5rSDuwvV9W=K7EQsMrucZSBZ006rqLVfV1E-B6tjW5jw@mail.gmail.com>
Date:   Thu, 31 May 2018 09:14:30 -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 3/8] ixgbe: implement flush flag for ndo_xdp_xmit

On Thu, May 31, 2018 at 1:59 AM, Jesper Dangaard Brouer
<brouer@...hat.com> wrote:
> When passed the XDP_XMIT_FLUSH flag ixgbe_xdp_xmit now performs the
> same kind of ring tail update as in ixgbe_xdp_flush.  The update tail
> code in ixgbe_xdp_flush is generalized and shared with ixgbe_xdp_xmit.
>
> Signed-off-by: Jesper Dangaard Brouer <brouer@...hat.com>

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

> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |   20 ++++++++++++++------
>  1 file changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> index 87f088f4af52..4fd77c9067f2 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> @@ -10022,6 +10022,15 @@ static int ixgbe_xdp(struct net_device *dev, struct netdev_bpf *xdp)
>         }
>  }
>
> +static void ixgbe_xdp_ring_update_tail(struct ixgbe_ring *ring)
> +{
> +       /* Force memory writes to complete before letting h/w know there
> +        * are new descriptors to fetch.
> +        */
> +       wmb();
> +       writel(ring->next_to_use, ring->tail);
> +}
> +
>  static int ixgbe_xdp_xmit(struct net_device *dev, int n,
>                           struct xdp_frame **frames, u32 flags)
>  {
> @@ -10033,7 +10042,7 @@ static int ixgbe_xdp_xmit(struct net_device *dev, int n,
>         if (unlikely(test_bit(__IXGBE_DOWN, &adapter->state)))
>                 return -ENETDOWN;
>
> -       if (unlikely(flags & ~XDP_XMIT_FLAGS_NONE))
> +       if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
>                 return -EINVAL;
>
>         /* During program transitions its possible adapter->xdp_prog is assigned
> @@ -10054,6 +10063,9 @@ static int ixgbe_xdp_xmit(struct net_device *dev, int n,
>                 }
>         }
>
> +       if (unlikely(flags & XDP_XMIT_FLUSH))
> +               ixgbe_xdp_ring_update_tail(ring);
> +
>         return n - drops;
>  }
>
> @@ -10072,11 +10084,7 @@ static void ixgbe_xdp_flush(struct net_device *dev)
>         if (unlikely(!ring))
>                 return;
>
> -       /* Force memory writes to complete before letting h/w know there
> -        * are new descriptors to fetch.
> -        */
> -       wmb();
> -       writel(ring->next_to_use, ring->tail);
> +       ixgbe_xdp_ring_update_tail(ring);
>
>         return;
>  }
>