netdev - Re: network driver takedown at reboof -f ?

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Message-ID: <191adc26-28d3-758a-7c9a-53e71a62b0fa@gmail.com>
Date:   Thu, 14 Jul 2022 07:58:53 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Joakim Tjernlund <Joakim.Tjernlund@...inera.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: network driver takedown at reboof -f ?

On 7/14/2022 7:21 AM, Joakim Tjernlund wrote:
> Doing a fast reboot -f I notice that the ethernet I/Fs are NOT shutdown/stopped.
> Is this expected? I sort of expected kernel to do ifconfig down automatically.
> 
> Is there some function in netdev I can hook into to make reboot shutdown my eth I/Fs?

If you want that to happen you typically have to implement a ->shutdown 
callback in your network driver registered via platform/pci/bus, if 
nothing else to turn off all DMAs and prevent, e.g.: a kexec'd kernel to 
be corrupted by a wild DMA engine still running.

There is no generic provision in the network stack to deal with those cases.

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d9f45ab9e671166004b75427f10389e1f70cfc30
-- 
Florian