Re: [patch 4/4] MFD: Change mfd platform device usage to wrapper platform_device

From: Ben Dooks
Date: Wed Jul 09 2008 - 17:05:04 EST



On Wed, Jul 09, 2008 at 09:56:25PM +0100, Russell King - ARM Linux wrote:
> On Wed, Jul 09, 2008 at 11:49:20AM +0100, Ben Dooks wrote:
> > This patch changes the mfd core behaviour to wrapper the platform_device
> > it creates in an struct mfd_device which contains the information
> > about the cell that was created.
>
> You can't do this. Grab a reference to the platform device (by holding
> one of its sysfs files open) and then remove all the users of the mfd-core
> module and the mfd-core module itself.
>
> Then, read from that file and close it. Watch your kernel oops.
>
> That's why device release methods inside modules are a BAD IDEA and why
> we have the platform device alloc API.

Would this be fixed by grabbing a reference to the mfd-core module whilst
the mfd device is open?

--
Ben

Q: What's a light-year?
A: One-third less calories than a regular year.

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