Re: [PATCH v2.57] datapath: Add basic MPLS support to kernel

[Thomas Graf <tgraf-G/eBtMaohhA@public.gmane.org>]

On 05/20/14 at 07:02am, Simon Horman wrote:
> [PATCH] datapath: 16bit inner_network_header field in struct ovs_gso_cb
> 
> The motivation for this is to create a 16bit hole in struct ovs_gso_cb
> which may be used for the inner_protocol field which is needed
> for the proposed implementation of compatibility for MPLS GSO segmentation.
> 
> This should be safe as inner_network_header is now an offset to
> the inner_mac_header rather than skb->head.
> 
> As pointed out by Thomas Graf simply making both inner offsets 16bis is not
> safe as there have been cases of overflow with "with collapsed TCP frames
> on IB when the headroom grew beyond 64K. See commit 50bceae9bd ``tcp:
> Reallocate headroom if it would overflow csum_start'' for additional
> details."
> 
> This patch is based on suggestions by Thomas Graf and Jesse Gross.
> 
> Cc: Thomas Graf <tgraf-G/eBtMaohhA@public.gmane.org>
> Cc: Jesse Gross <jesse-l0M0P4e3n4LQT0dZR+AlfA@public.gmane.org>
> Signed-off-by: Simon Horman <horms-/R6kz+dDXgpPR4JQBCEnsQ@public.gmane.org>

LGTM

Reviewed-by: Thomas Graf <tgraf-G/eBtMaohhA@public.gmane.org>