> -----Original Message-----
> From: Greg KH [mailto:[email protected]]
> Sent: Friday, October 20, 2017 8:22 AM
> To: Limonciello, Mario <[email protected]>
> Cc: [email protected]; Andy Shevchenko <[email protected]>;
> LKML <[email protected]>; [email protected]; Andy
> Lutomirski <[email protected]>; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected]; Alan Cox
> <[email protected]>
> Subject: Re: [PATCH v10 13/15] platform/x86: wmi: create userspace interface
> for
> drivers
>
> On Thu, Oct 19, 2017 at 12:50:16PM -0500, Mario Limonciello wrote:
> > + wblock = container_of(wdev, struct wmi_block, dev);
> > + if (!wblock)
> > + return -ENODEV;
>
> How can container_of() ever return NULL? If so, you have a very odd
> memory layout...
>
I'm assuming this is from set_required_buffer_size right?
The symbol is exported out for other drivers to use. It's possible for another
driver to allocate a wmi_device structure that's not part of a wblock.
> > + list_for_each_entry_safe(wblock, next, &wmi_block_list, list) {
> > + wdriver = container_of(wblock->dev.dev.driver,
> > + struct wmi_driver, driver);
> > + if (!wdriver)
> > + continue;
>
> Same here. And other places in this file.
>
This one it's possible that a driver isn't bound to a device, and when
that happens wdriver is NULL.
