Subject: Re: [PATCH net-next v2] openvswitch: Pad OVS_PACKET_ATTR_PACKET if linear copy was performed

From: Zoltan Kiss <[email-masked]>
Date: Tue, 14 Jan 2014 18:56:52 +0000

It works for me, thanks!

Acked-by: Zoltan Kiss <[email-masked]>

On 14/01/14 16:27, Thomas Graf wrote:
> While the zerocopy method is correctly omitted if user space
> does not support unaligned Netlink messages. The attribute is
> still not padded correctly as skb_zerocopy() will not ensure
> padding and the attribute size is no longer pre calculated
> though nla_reserve() which ensured padding previously.
>
> This patch applies appropriate padding if a linear data copy
> was performed in skb_zerocopy().
>
> Signed-off-by: Thomas Graf <[email-masked]>
> ---
> v2: initialize padding to 0's
>
>   net/openvswitch/datapath.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
> index df46928..3ca9121 100644
> --- a/net/openvswitch/datapath.c
> +++ b/net/openvswitch/datapath.c
> @@ -396,7 +396,7 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
>   		.dst_sk = ovs_dp_get_net(dp)->genl_sock,
>   		.snd_portid = upcall_info->portid,
>   	};
> -	size_t len;
> +	size_t len, plen;
>   	unsigned int hlen;
>   	int err, dp_ifindex;
>
> @@ -466,6 +466,11 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
>
>   	skb_zerocopy(user_skb, skb, skb->len, hlen);
>
> +	/* Pad OVS_PACKET_ATTR_PACKET if linear copy was performed */
> +	if (!(dp->user_features & OVS_DP_F_UNALIGNED) &&
> +	    (plen = (ALIGN(user_skb->len, NLA_ALIGNTO) - user_skb->len)) > 0)
> +		memset(skb_put(user_skb, plen), 0, plen);
> +
>   	((struct nlmsghdr *) user_skb->data)->nlmsg_len = user_skb->len;
>
>   	err = genlmsg_unicast(ovs_dp_get_net(dp), user_skb, upcall_info->portid);
>