Re: [PATCH net-next v4 1/8] net: ethtool: Set the req_info->dev on DUMP requests for each dev

[Kory Maincent <kory.maincent@bootlin.com>]

On Mon, 24 Mar 2025 11:40:03 +0100
Maxime Chevallier <maxime.chevallier@bootlin.com> wrote:

> There are a few netlink commands that rely on the req_info->dev field
> being populated by ethnl in their ->prepare_data() and ->fill_reply().
> 
> For a regular GET request, this will be set by ethnl_default_parse(),
> which calls ethnl_parse_header_dev_get().
> 
> In the case of a DUMP request, the ->prepare_data() and ->fill_reply()
> callbacks will be called with the req_info->dev being NULL, which can
> cause discrepancies in the behaviour between GET and DUMP results.
> 
> The main impact is that ethnl_req_get_phydev() will not find any
> phy_device, impacting :
>  - plca
>  - pse-pd
>  - stats
> 
> Some other commands rely on req_info->dev, namely :
>  - coalesce in ->fill_reply to look for an irq_moder
> 
> Although cable_test and tunnels also rely on req_info->dev being set,
> that's not a problem for these commands as :
>  - cable_test doesn't support DUMP
>  - tunnels rolls its own ->dumpit (and sets dev in the req_info).
>  - phy also has its own ->dumpit
> 
> All other commands use reply_data->dev (probably the correct way of
> doing things) and aren't facing this issue.
> 
> Simply set the dev in the req_info context when iterating to dump each
> dev.

Tested-by: Kory Maincent <kory.maincent@bootlin.com>
Reviewed-by: Kory Maincent <kory.maincent@bootlin.com>

Thank you, this fixes the PSE dump!

Regards,
-- 
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com