Re: [PATCH 1/1] usb: ulpi: don't register drivers if bus doesn't exist

[Lu, Baolu]

Hi Heikki, Sasha and others,

Please ignore this patch. I should not squash these two patches into one and
sign it off behalf of other people. I apologize for this and I'm sorry 
if this lets
you feel affronted.

Thanks,
Baolu


On 05/21/2015 04:57 PM, Lu Baolu wrote:
> ULPI registers its bus at module_init, so if the bus fails to register, the
> module will fail to load and all will be well in the world.
>
> However, if the ULPI code is built-in rather than a module, the bus
> initialization may fail, but we'd still try to register drivers later onto
> a non-existent bus, which will panic the kernel.
>
> Fix that by checking that the bus was indeed initialized before trying to
> register drivers on top of it.
>
> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
> Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Reported-by: Zhuo Qiuxu <qiuxu.zhuo@xxxxxxxxx>
> Reviewed-by: David Cohen <david.a.cohen@xxxxxxxxxxxxxxx>
> ---
>   drivers/usb/common/ulpi.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c
> index 0e6f968..af52b46 100644
> --- a/drivers/usb/common/ulpi.c
> +++ b/drivers/usb/common/ulpi.c
> @@ -132,6 +132,10 @@ int ulpi_register_driver(struct ulpi_driver *drv)
>   	if (!drv->probe)
>   		return -EINVAL;
>   
> +	/* Was the bus registered successfully? */
> +	if (unlikely(WARN_ON(!ulpi_bus.p)))
> +		return -ENODEV;
> +
>   	drv->driver.bus = &ulpi_bus;
>   
>   	return driver_register(&drv->driver);
> @@ -242,7 +246,7 @@ static int __init ulpi_init(void)
>   {
>   	return bus_register(&ulpi_bus);
>   }
> -module_init(ulpi_init);
> +subsys_initcall(ulpi_init);
>   
>   static void __exit ulpi_exit(void)
>   {

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