netdev - Re: [PATCH 1/2] udp: fix gso

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Message-ID: <CAKgT0Ue092M4pMa8EjrqdF6KADK8WtFhA=17K3fuqW5=xKAeNg@mail.gmail.com>
Date:   Mon, 30 Sep 2019 16:51:13 -0700
From:   Alexander Duyck <alexander.duyck@...il.com>
To:     Josh Hunt <johunt@...mai.com>
Cc:     David Miller <davem@...emloft.net>,
        Netdev <netdev@...r.kernel.org>,
        Eric Dumazet <edumazet@...gle.com>,
        Willem de Bruijn <willemb@...gle.com>,
        "Duyck, Alexander H" <alexander.h.duyck@...el.com>
Subject: Re: [PATCH 1/2] udp: fix gso_segs calculations

On Mon, Sep 30, 2019 at 3:15 PM Josh Hunt <johunt@...mai.com> wrote:
>
> Commit dfec0ee22c0a ("udp: Record gso_segs when supporting UDP segmentation offload")
> added gso_segs calculation, but incorrectly got sizeof() the pointer and
> not the underlying data type. It also does not account for v6 UDP GSO segs.
>
> Fixes: dfec0ee22c0a ("udp: Record gso_segs when supporting UDP segmentation offload")
> Signed-off-by: Josh Hunt <johunt@...mai.com>
> ---
>  net/ipv4/udp.c | 2 +-
>  net/ipv6/udp.c | 2 ++
>  2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
> index cf755156a684..be98d0b8f014 100644
> --- a/net/ipv4/udp.c
> +++ b/net/ipv4/udp.c
> @@ -856,7 +856,7 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
>
>                 skb_shinfo(skb)->gso_size = cork->gso_size;
>                 skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
> -               skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(len - sizeof(uh),
> +               skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(len - sizeof(*uh),
>                                                          cork->gso_size);
>                 goto csum_partial;
>         }
> diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
> index aae4938f3dea..eb9a9934ac05 100644
> --- a/net/ipv6/udp.c
> +++ b/net/ipv6/udp.c
> @@ -1143,6 +1143,8 @@ static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6,
>
>                 skb_shinfo(skb)->gso_size = cork->gso_size;
>                 skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
> +               skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(len - sizeof(*uh),
> +                                                        cork->gso_size);
>                 goto csum_partial;
>         }
>

Fix looks good to me.

You might also want to add the original commit since you are also
addressing IPv6 changes which are unrelated to my commit that your
referenced:
Fixes: bec1f6f69736 ("udp: generate gso with UDP_SEGMENT")

Reviewed-by: Alexander Duyck <alexander.h.duyck@...ux.intel.com>