Re: [RFC net-next PATCH 2/5] mlx5: fix bug reading rss_hash_type from CQE

Daniel Borkmann
2017-05-19T15:47:08Z

On 05/18/2017 05:41 PM, Jesper Dangaard Brouer wrote:
> Masks for extracting part of the Completion Queue Entry (CQE)
> field rss_hash_type was swapped, namely CQE_RSS_HTYPE_IP and
> CQE_RSS_HTYPE_L4.
>
> The bug resulted in setting skb->l4_hash, even-though the
> rss_hash_type indicated that hash was NOT computed over the
> L4 (UDP or TCP) part of the packet.
>
> Added comments from the datasheet, to make it more clear what
> these masks are selecting.
>
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> ---

Stand-alone fix for -net tree?

> include/linux/mlx5/device.h | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/mlx5/device.h b/include/linux/mlx5/device.h
> index dd9a263ed368..a940ec6a046c 100644
> --- a/include/linux/mlx5/device.h
> +++ b/include/linux/mlx5/device.h
> @@ -787,8 +787,14 @@ enum {
> };
>
> enum {
> - CQE_RSS_HTYPE_IP = 0x3 << 6,
> - CQE_RSS_HTYPE_L4 = 0x3 << 2,
> + CQE_RSS_HTYPE_IP = 0x3 << 2,
> + /* cqe->rss_hash_type[3:2] - IP destination selected for hash
> + * (00 = none, 01 = IPv4, 10 = IPv6, 11 = Reserved)
> + */
> + CQE_RSS_HTYPE_L4 = 0x3 << 6,
> + /* cqe->rss_hash_type[7:6] - L4 destination selected for hash
> + * (00 = none, 01 = TCP. 10 = UDP, 11 = IPSEC.SPI
> + */
> };
>
> enum {
>