From: "Michal Suchánek" <msuchanek@suse.de>
To: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Peter Huewe <peterhuewe@gmx.de>,
Marcel Selhorst <tpmdd@selhorst.net>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
linux-kernel@vger.kernel.org, tpmdd-devel@lists.sourceforge.net
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: <25eaf1ea1d44f7950dbca6b3c4598c48@suse.de> (raw)
In-Reply-To: <20170810163057.GA21485@obsidianresearch.com>
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
run.
>
>> > 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
down.
>
>> 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.
Thanks
Michal
next prev parent 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 [PATCH] Do not disable driver and bus shutdown hook when class shutdown hook is set 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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