Re: [2/9] driver core fixes: device_register() retval check in platform.c

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Fri, Sep 22, 2006 at 11:36:55AM +0200, Cornelia Huck wrote:
> From: Cornelia Huck <cornelia.huck@de.ibm.com>
> 
> Check the return value of device_register() in platform_bus_init().
> 
> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> 
> ---
>  drivers/base/platform.c |   11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> --- linux-2.6-CH.orig/drivers/base/platform.c
> +++ linux-2.6-CH/drivers/base/platform.c
> @@ -563,8 +563,15 @@ EXPORT_SYMBOL_GPL(platform_bus_type);
>  
>  int __init platform_bus_init(void)
>  {
> -	device_register(&platform_bus);
> -	return bus_register(&platform_bus_type);
> +	int error;
> +
> +	error = device_register(&platform_bus);
> +	if (error)
> +		return error;
> +	error =  bus_register(&platform_bus_type);
> +	if (error)
> +		device_unregister(&platform_bus);
> +	return error;

I don't think there's much value in patches such as this - if the
platform bus type didn't register, what happens when we then try
to register a platform device driver or a platform device?  ISTR
doing that before the bus type is registered leads to an OOPS.

So, presumably to do this properly, if the platform_bus_type failed
to register, you need to force all platform device/platform device
driver registrations to also fail.

At that point, is the added complexity really worth it?

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core