Re: Driver bind/unbind and __devinit

[Greg KH <gregkh@suse.de>]

On Thu, Dec 08, 2005 at 04:14:58PM -0500, Dmitry Torokhov wrote:
> Hi,
> 
> Many drivers have their probe routines declared as __devinit which is
> a no-op unless CONFIG_HOTPLUG is set. However driver's bind/unbind
> attributes are created unconditionally, as fas as I can see. Would not
> it cause an oops if someone tries to use these attributes with
> CONFIG_HOTPLUG=N? Am I missing something?

You are missing the CONFIG_HOTPLUG checks around the functions that add
and check the device ids from these sysfs files.  If CONFIG_HOTPLUG is
not enabled, those files do not do anything.

In 2.6.16, CONFIG_HOTPLUG is moving under CONFIG_EMBEDDED, so the odds
of people disabling it are going to be pretty small now.

> Also, unbind implementation does not seem safe - we check the driver
> before taking device's semaphore so we risk unbinding wrong driver (in
> the unlikely event that we manage to unbind and bind another driver in
> another thread).

Do you have a suggestion as to how to fix this?

thanks,

greg k-h