Re: [linux-nics] [PATCH net 3/5] fm10k: Implement ndo_gso_check()

On Fri, 07 Nov 2014 14:20:08 Vick, Matthew wrote:

On 11/6/14, 4:55 PM, "Joe Stringer" [off-list ref] wrote:

quoted

On Thu, Nov 06, 2014 at 11:58:32PM +0000, Vick, Matthew wrote:

quoted

On 11/5/14, 11:36 AM, "Jeff Kirsher" [off-list ref]

wrote:
Hi Joe, fm10k's hardware is pretty lax about the header size. As long as
the total header length (outer+inner) is 184 bytes or less we're golden,
so if I'm not mistaken that leaves us with a max of 130 bytes beyond the
tunnel header.

Oh, okay. To be more explicit, in the case of UDP tunnels I take it that
you're talking about L2+L3+(L4+)tunnel+L2+L3+L4 <= 184? (L4 perhaps
optional depending on the tunnel protocol used)

In that case, the fm10k_gso_check would use something closer to
"skb_inner_transport_header(skb) - skb_mac_header(skb) > 184", or
perhaps 164 to allow for inner L4 header (?).

Joe

Yes, I'm talking about the full shebang.

I like the 164 check, personally (with appropriate #define for
readability).

Thanks for the feedback, I take it that this approach is preferable over the 
other one involving an skb_gso_check() + fm10k_tx_encap_offload() call?