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From: "Michal Suchánek" <>
To: Jason Gunthorpe <>
Cc: Greg Kroah-Hartman <>,
	Peter Huewe <>,
	Marcel Selhorst <>,
	Jarkko Sakkinen <>,,
Subject: Re: [PATCH] Do not disable driver and bus shutdown hook when class shutdown hook is set.
Date: Fri, 11 Aug 2017 07:04:03 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 2017-08-10 18:30, Jason Gunthorpe wrote:
> On Thu, Aug 10, 2017 at 12:18:11PM +0200, Michal Suchánek wrote:

>> > Existing bus implementations do properly chain to driver shutdown (eg
>> > look at mmc_bus_shutdown) and it appears to have been written like
>> Neither isa nor ibmebus does. These are two random buses I tried to
>> look at.
> I'm not following, I see this:
> static void ibmebus_bus_device_shutdown(struct device *dev)
> {
>         struct platform_device *of_dev = to_platform_device(dev);
>         struct platform_driver *drv = to_platform_driver(dev->driver);
>         if (dev->driver && drv->shutdown)
>                 drv->shutdown(of_dev);
> }
> It looks to me like in this case the struct device_driver shutdown is
> not used, and instead the struct platform_driver shutdown is called.

And it is not used even if a device driver sets it and expects it to 

>> > this so that the bus can insert code before and after calling the
>> > driver shutdown.
>> So basically there is bus pre-shutdown and post-shutdown hook jumbled
>> together in one function.
> and a redirect, apparently.
>> While I can understand the concept of post-shutdown hook I wonder
>> what gross hack would require a pre-shutdown hook.
> TPM requires pre-shutdown.

Yes, a class pre-shutdown. Not a bus pre-shutdown, however.

I have no idea what business has a bus driver before a device shuts 

>> The Linux development process at its best. There is poor design
>> implemented so when touching the code it is extended to worse because
> I'm not sure I completely agree, there is obviously a lot going on with
> bus->shutdown.
> If you want to go ahead with your patch then please also rename the
> class shutdown to shutdown_pre to make it clear it is doing something
> different.

That makes sense.



  reply	other threads:[~2017-08-11  5:04 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-09 21:34 Michal Suchanek
2017-08-09 21:52 ` Jason Gunthorpe
2017-08-10 10:18   ` Michal Suchánek
2017-08-10 16:30     ` Jason Gunthorpe
2017-08-11  5:04       ` Michal Suchánek [this message]
2017-08-11 15:28         ` Henrique de Moraes Holschuh
2017-08-11 17:01           ` Michal Suchánek
2017-08-11 11:50   ` Jarkko Sakkinen

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