Re: [PATCH] xen-netback: correct success/error reporting for the SKB-with-fraglist case

[Paul Durrant <xadimgnik@xxxxxxxxx>]

On 23/02/2021 16:29, Jan Beulich wrote:
> When re-entering the main loop of xenvif_tx_check_gop() a 2nd time, the
> special considerations for the head of the SKB no longer apply. Don't
> mistakenly report ERROR to the frontend for the first entry in the list,
> even if - from all I can tell - this shouldn't matter much as the overall
> transmit will need to be considered failed anyway.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> --- a/drivers/net/xen-netback/netback.c
> +++ b/drivers/net/xen-netback/netback.c
> @@ -499,7 +499,7 @@ check_frags:
>                                  * the header's copy failed, and they are
>                                  * sharing a slot, send an error
>                                  */
> -                               if (i == 0 && sharedslot)
> +                               if (i == 0 && !first_shinfo && sharedslot)
>                                         xenvif_idx_release(queue, pending_idx,
>                                                            XEN_NETIF_RSP_ERROR);
>                                 else
I think this will DTRT, but to my mind it would make more sense to clear 
'sharedslot' before the 'goto check_frags' at the bottom of the function.
  Paul