netdev - Re: [PATCH net-next 01/15] ice: Add E830 checksum offload support

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Message-ID: <4b22a368-d266-442b-9cad-6c40688f735b@intel.com>
Date: Fri, 8 Nov 2024 15:53:47 -0800
From: "Greenwalt, Paul" <paul.greenwalt@...el.com>
To: Jakub Kicinski <kuba@...nel.org>
CC: Tony Nguyen <anthony.l.nguyen@...el.com>, <davem@...emloft.net>,
	<pabeni@...hat.com>, <edumazet@...gle.com>, <andrew+netdev@...n.ch>,
	<netdev@...r.kernel.org>, Alice Michael <alice.michael@...el.com>, "Eric
 Joyner" <eric.joyner@...el.com>, Alexander Lobakin
	<aleksander.lobakin@...el.com>, Pucha Himasekhar Reddy
	<himasekharx.reddy.pucha@...el.com>
Subject: Re: [PATCH net-next 01/15] ice: Add E830 checksum offload support

On 11/7/2024 8:14 PM, Jakub Kicinski wrote:
> On Thu, 7 Nov 2024 17:37:41 -0800 Greenwalt, Paul wrote:
>>> why dropping what the user requested with a warning and not just return
>>> an error from ice_set_features()?  
>>
>> I took this approach of reducing the feature set to resolve the device
>> NETIF_F_HW_CSUM and NETIF_F_ALL_TSO feature limitation, which seemed
>> consistent with the guidance in the netdev-features documentation.
> 
> My understanding of that guidance is that it is for "positive"
> dependencies. Feature A requires feature B, so if feature B is
> cleared so should the feature A. Here we have a feature conflict.

Hi Jakub,

I also considered the netdevice.h comment for the ndo_fix_features hook,
which states, 'Adjusts the requested feature flags according to
device-specific constraints, and returns the resulting flags.'
Additionally, since this patch introduces E830 NETIF_F_HW_CSUM support I
reviewed the netdev_fix_features handling of NETIF_F_HW_CSUM and
(NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM), which seemed similar—though that
case deals with a feature conflict rather than a device conflict. These
led me to take this approach to achieve a consistent implementation.

Thanks,
Paul