Re: [PATCH 1/2] hp-wmi: fix unregister order in hp_wmi_rfkill_setup() once again

From: Maciej S. Szmigiero
Date: Tue Mar 08 2016 - 10:59:03 EST

Hi Darren,

Thanks for review, see also my comments below.

On 08.03.2016 13:39, Darren Hart wrote:
> On Sun, Mar 06, 2016 at 11:38:36PM +0100, Maciej S. Szmigiero wrote:
>> --- a/drivers/platform/x86/hp-wmi.c
>> +++ b/drivers/platform/x86/hp-wmi.c
>> @@ -746,7 +746,7 @@ static int __init hp_wmi_rfkill_setup(struct platform_device *device)
>> (void *) HPWMI_BLUETOOTH);
>> if (!bluetooth_rfkill) {
>> err = -ENOMEM;
>> - goto register_wifi_error;
>> + goto register_bluetooth_error;
> In this and all cases below, the goto label should match the situation, jumping
> to register_bluetooth_error would be incorrect as we experienced a wifi error.

Here we experienced an BT error - BT rkill allocation failed,
so jump is to "register_bluetooth_error".

The second jump to "register_bluetooth_error" is in another case of BT error:
when its rfkill registration failed.

It is the same label since if BT rfkill allocation had failed
rfkill_destroy(bluetooth_rfkill) call in cleanup does nothing but we still
need to possibly unregister WiFi rfkill that might have been registered in
a previews block (and then fall through to next label to destroy WiFi rfkill).

It would be possible to have separate jump labels skipping unnecessary
rfkill_destroy() calls on allocation failure, but this would mean
that we would have 7 labels in such small block of cleanup code.

> A better solution would be to reorder the labels in the exit block
> such that they enforce the necessary reverse order.

Cleanup labels already are in reverse order with regard to registration:
1) WiFi,
2) BT,
3) WWAN,
5) GPS.

1) GPS,
2) WWAN,
3) BT,
4) WiFi.

Best regards,
Maciej Szmigiero