Subject: Re: [PATCH net 1/5] openvswitch: Pad OVS_PACKET_ATTR_PACKET if linear copy was performed

From: Sergei Shtylyov <sergei.shtylyov-M4DtvfQ/[email-masked]>
Date: Mon, 03 Feb 2014 20:43:58 +0400

Hello.

On 03-02-2014 5:08, Jesse Gross wrote:

> From: Thomas Graf <tgraf-G/[email-masked]>

> 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 <tgraf-G/[email-masked]>
> Acked-by: Zoltan Kiss <[email-masked]>
> Signed-off-by: Jesse Gross <[email-masked]>
> ---
>   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
[...]
> @@ -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)

    This shouldn't pass checkpatch.pl which complains about assignments inside 
*if* statements.

WBR, Sergei