Re: [PATCH 0/3] net: macb: add pad and fcs support
From: David Miller
Date: Tue Aug 07 2018 - 16:19:13 EST
From: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
Date: Tue, 7 Aug 2018 12:25:11 +0300
> In [1] it was reported that UDP checksum is offloaded to hardware no mather
> it was previously computed in software or not. The proposal on [1] was to
> disable TX checksum offload.
>
> This series (mostly patch 3/3) address the issue described at [1] by
> setting NOCRC bit to TX buffer descriptor for SKBs that arrived from
> networking stack with checksum computed. For these packets padding and FCS
> need to be added (hardware doesn't compute them if NOCRC bit is set). The
> minimum packet size that hardware expects is 64 bytes (including FCS).
> This feature could not be used in case of GSO, so, it was used only for
> no GSO SKBs.
>
> For SKBs wich requires padding and FCS computation macb_pad_and_fcs()
> checks if there is enough headroom and tailroom in SKB to avoid copying
> SKB structure. Since macb_pad_and_fcs() may change SKB the
> macb_pad_and_fcs() was places in macb_start_xmit() b/w macb_csum_clear()
> and skb_headlen() calls.
>
> This patch was tested with pktgen in kernel tool in a script like this:
> (pktgen_sample01_simple.sh is at [2]):
...
Series applied to net-next, thanks.