On Fri, Aug 21, 2020 at 6:50 AM Greg Rose <[email protected]> wrote:
>
> From: Tonghao Zhang <[email protected]>
>
> Upstream commit:
>     commit 61ca533c0e94104c35fcb7858a23ec9a05d78143
>     Author: Tonghao Zhang <[email protected]>
>     Date:   Thu Nov 14 23:51:08 2019 +0800
>
>     net: openvswitch: don't call pad_packet if not necessary
>
>     The nla_put_u16/nla_put_u32 makes sure that
>     *attrlen is align. The call tree is that:
>
>     nla_put_u16/nla_put_u32
>       -> nla_put                attrlen = sizeof(u16) or sizeof(u32)
>       -> __nla_put              attrlen
>       -> __nla_reserve  attrlen
>       -> skb_put(skb, nla_total_size(attrlen))
>
>     nla_total_size returns the total length of attribute
>     including padding.
>
>     Cc: Joe Stringer <[email protected]>
>     Cc: William Tu <[email protected]>
>     Signed-off-by: Tonghao Zhang <[email protected]>
>     Acked-by: Pravin B Shelar <[email protected]>
>     Signed-off-by: David S. Miller <[email protected]>
>
> Cc: Tonghao Zhang <[email protected]>
> Signed-off-by: Greg Rose <[email protected]>
Reviewed-by: Tonghao Zhang <[email protected]>
> ---
>  datapath/datapath.c | 22 ++++++++--------------
>  1 file changed, 8 insertions(+), 14 deletions(-)
>
> diff --git a/datapath/datapath.c b/datapath/datapath.c
> index f04ce21..b9ac676 100644
> --- a/datapath/datapath.c
> +++ b/datapath/datapath.c
> @@ -512,23 +512,17 @@ static int queue_userspace_packet(struct datapath *dp, 
> struct sk_buff *skb,
>         }
>
>         /* Add OVS_PACKET_ATTR_MRU */
> -       if (upcall_info->mru) {
> -               if (nla_put_u16(user_skb, OVS_PACKET_ATTR_MRU,
> -                               upcall_info->mru)) {
> -                       err = -ENOBUFS;
> -                       goto out;
> -               }
> -               pad_packet(dp, user_skb);
> +       if (upcall_info->mru &&
> +           nla_put_u16(user_skb, OVS_PACKET_ATTR_MRU, upcall_info->mru)) {
> +               err = -ENOBUFS;
> +               goto out;
>         }
>
>         /* Add OVS_PACKET_ATTR_LEN when packet is truncated */
> -       if (cutlen > 0) {
> -               if (nla_put_u32(user_skb, OVS_PACKET_ATTR_LEN,
> -                               skb->len)) {
> -                       err = -ENOBUFS;
> -                       goto out;
> -               }
> -               pad_packet(dp, user_skb);
> +       if (cutlen > 0 &&
> +           nla_put_u32(user_skb, OVS_PACKET_ATTR_LEN, skb->len)) {
> +               err = -ENOBUFS;
> +               goto out;
>         }
>
>         /* Add OVS_PACKET_ATTR_HASH */
> --
> 1.8.3.1
>


-- 
Best regards, Tonghao
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