netdev - Re: [Intel-wired-lan] [PATCH v2 iwl-next] igb: set skb hash type from RSS

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Message-ID: <ab7b6df0-53d6-4304-8e65-5f1e243d9615@molgen.mpg.de>
Date: Thu, 22 Jan 2026 16:00:02 +0100
From: Paul Menzel <pmenzel@...gen.mpg.de>
To: Kohei Enju <kohei@...uk.jp>
Cc: intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org,
 Tony Nguyen <anthony.l.nguyen@...el.com>,
 Przemek Kitszel <przemyslaw.kitszel@...el.com>,
 Andrew Lunn <andrew+netdev@...n.ch>, "David S. Miller"
 <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
 kohei.enju@...il.com, Aleksandr Loktionov <aleksandr.loktionov@...el.com>
Subject: Re: [Intel-wired-lan] [PATCH v2 iwl-next] igb: set skb hash type from
 RSS_TYPE

Dear Kohei,


Thank you for your patch.

Am 22.01.26 um 14:47 schrieb Kohei Enju:
> igb always marks the RX hash as L3 regardless of RSS_TYPE in the
> advanced descriptor, which may indicate L4 (TCP/UDP) hash. This can
> trigger unnecessary SW hash recalculation and breaks toeplitz selftests.
> 
> Use RSS_TYPE from pkt_info to set the correct PKT_HASH_TYPE_*
> 
> Tested by toeplitz.py with the igb RSS key get/set patches applied as
> they are required for toeplitz.py (see Link below).
>   # ethtool -N $DEV rx-flow-hash udp4 sdfn
>   # ethtool -N $DEV rx-flow-hash udp6 sdfn
>   # python toeplitz.py | grep -E "^# Totals"
> 
> Without patch:
>   # Totals: pass:0 fail:12 xfail:0 xpass:0 skip:0 error:0
> 
> With patch:
>   # Totals: pass:12 fail:0 xfail:0 xpass:0 skip:0 error:0
> 
> Link: https://lore.kernel.org/intel-wired-lan/20260119084511.95287-5-takkozu@amazon.com/
> Signed-off-by: Kohei Enju <kohei@...uk.jp>
> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@...el.com>
> ---
> Changelog:
>    v2:
>      - Fix max-line-length by removing unnecessary comment
>    v1: https://lore.kernel.org/intel-wired-lan/20260119175922.199950-1-kohei@enjuk.jp/
> ---
>   drivers/net/ethernet/intel/igb/e1000_82575.h | 21 ++++++++++++++++++++
>   drivers/net/ethernet/intel/igb/igb_main.c    | 18 +++++++++++++----
>   2 files changed, 35 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/igb/e1000_82575.h b/drivers/net/ethernet/intel/igb/e1000_82575.h
> index 63ec253ac788..9e696d55e512 100644
> --- a/drivers/net/ethernet/intel/igb/e1000_82575.h
> +++ b/drivers/net/ethernet/intel/igb/e1000_82575.h
> @@ -87,6 +87,27 @@ union e1000_adv_rx_desc {
>   	} wb;  /* writeback */
>   };
>   
> +#define E1000_RSS_TYPE_NO_HASH		 0
> +#define E1000_RSS_TYPE_HASH_TCP_IPV4	 1
> +#define E1000_RSS_TYPE_HASH_IPV4	 2
> +#define E1000_RSS_TYPE_HASH_TCP_IPV6	 3
> +#define E1000_RSS_TYPE_HASH_IPV6_EX	 4
> +#define E1000_RSS_TYPE_HASH_IPV6	 5
> +#define E1000_RSS_TYPE_HASH_TCP_IPV6_EX	 6
> +#define E1000_RSS_TYPE_HASH_UDP_IPV4	 7
> +#define E1000_RSS_TYPE_HASH_UDP_IPV6	 8
> +#define E1000_RSS_TYPE_HASH_UDP_IPV6_EX	 9
> +
> +#define E1000_RSS_TYPE_MASK		GENMASK(3, 0)
> +
> +#define E1000_RSS_L4_TYPES_MASK	\
> +	(BIT(E1000_RSS_TYPE_HASH_TCP_IPV4)	| \
> +	 BIT(E1000_RSS_TYPE_HASH_TCP_IPV6)	| \
> +	 BIT(E1000_RSS_TYPE_HASH_TCP_IPV6_EX)	| \
> +	 BIT(E1000_RSS_TYPE_HASH_UDP_IPV4)	| \
> +	 BIT(E1000_RSS_TYPE_HASH_UDP_IPV6)	| \
> +	 BIT(E1000_RSS_TYPE_HASH_UDP_IPV6_EX))
> +
>   #define E1000_RXDADV_HDRBUFLEN_MASK      0x7FE0
>   #define E1000_RXDADV_HDRBUFLEN_SHIFT     5
>   #define E1000_RXDADV_STAT_TS             0x10000 /* Pkt was time stamped */
> diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
> index 8dab133296ca..ef0cbf532716 100644
> --- a/drivers/net/ethernet/intel/igb/igb_main.c
> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> @@ -8824,10 +8824,20 @@ static inline void igb_rx_hash(struct igb_ring *ring,
>   			       union e1000_adv_rx_desc *rx_desc,
>   			       struct sk_buff *skb)
>   {
> -	if (ring->netdev->features & NETIF_F_RXHASH)
> -		skb_set_hash(skb,
> -			     le32_to_cpu(rx_desc->wb.lower.hi_dword.rss),
> -			     PKT_HASH_TYPE_L3);
> +	u16 rss_type;
> +
> +	if (!(ring->netdev->features & NETIF_F_RXHASH))
> +		return;
> +
> +	rss_type = le16_to_cpu(rx_desc->wb.lower.lo_dword.pkt_info) &
> +		   E1000_RSS_TYPE_MASK;
> +
> +	if (!rss_type)
> +		return;
> +
> +	skb_set_hash(skb, le32_to_cpu(rx_desc->wb.lower.hi_dword.rss),
> +		     (E1000_RSS_L4_TYPES_MASK & BIT(rss_type)) ?
> +		     PKT_HASH_TYPE_L4 : PKT_HASH_TYPE_L3);
>   }
>   
>   /**

Reviewed-by: Paul Menzel <pmenzel@...gen.mpg.de>


Kind regards,

Paul