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From: Heiner Kallweit <hkallweit1@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: saeed@kernel.org, geert+renesas@glider.be, f.fainelli@gmail.com,
	andrew@lunn.ch, kuba@kernel.org, gaku.inami.xh@renesas.com,
	yoshihiro.shimoda.uh@renesas.com, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Revert "net: linkwatch: add check for netdevice being present to linkwatch_do_dev"
Date: Wed, 23 Sep 2020 22:44:30 +0200	[thread overview]
Message-ID: <e6f50a85-aa25-5fb7-7fd2-158668d55378@gmail.com> (raw)
In-Reply-To: <20200923.131529.637266321442993059.davem@davemloft.net>

On 23.09.2020 22:15, David Miller wrote:
> From: Heiner Kallweit <hkallweit1@gmail.com>
> Date: Wed, 23 Sep 2020 21:58:59 +0200
> 
>> On 23.09.2020 20:35, Saeed Mahameed wrote:
>>> Why would a driver detach the device on ndo_stop() ?
>>> seems like this is the bug you need to be chasing ..
>>> which driver is doing this ? 
>>>
>> Some drivers set the device to PCI D3hot at the end of ndo_stop()
>> to save power (using e.g. Runtime PM). Marking the device as detached
>> makes clear to to the net core that the device isn't accessible any
>> longer.
> 
> That being the case, the problem is that IFF_UP+!present is not a
> valid netdev state.
> 
If this combination is invalid, then netif_device_detach() should
clear IFF_UP? At a first glance this should be sufficient to avoid
the issue I was dealing with.

> Is it simply the issue that, upon resume, IFF_UP is marked true before
> the device is brought out from D3hot state and thus marked as present
> again?
> 
I can't really comment on that. The issue I was dealing with at the
time I submitted this change was about an async linkwatch event
(caused by powering down the PHY in ndo_stop) trying to access the
device when it was powered down already.

  reply	other threads:[~2020-09-23 20:44 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-01 15:02 [PATCH] Revert "net: linkwatch: add check for netdevice being present to linkwatch_do_dev" Geert Uytterhoeven
2020-09-03 21:58 ` David Miller
2020-09-10 19:20 ` David Miller
2020-09-11  6:32   ` Geert Uytterhoeven
2020-09-12  0:44     ` David Miller
2020-09-12 12:33       ` Geert Uytterhoeven
2020-09-13  1:34         ` David Miller
2020-09-14  7:40           ` Geert Uytterhoeven
2020-09-18 12:35             ` Nikolay Aleksandrov
2020-09-18 21:47               ` David Miller
2020-09-18 17:58 ` Saeed Mahameed
2020-09-18 22:10   ` David Miller
2020-09-23 11:49   ` Heiner Kallweit
2020-09-23 18:35     ` Saeed Mahameed
2020-09-23 19:58       ` Heiner Kallweit
2020-09-23 20:15         ` David Miller
2020-09-23 20:44           ` Heiner Kallweit [this message]
2020-09-23 22:42             ` Saeed Mahameed
2020-09-24  0:21               ` David Miller
2020-09-24  0:23                 ` David Miller
2020-09-24  5:49                   ` Saeed Mahameed
2020-09-24 16:03                     ` Jakub Kicinski
2020-09-24 18:16                       ` Saeed Mahameed

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