Re: [PATCH v4 1/4] HID: add driver for Valve Steam Controller
From: Andy Shevchenko
Date: Thu Mar 01 2018 - 05:20:49 EST
On Thu, Mar 1, 2018 at 12:49 AM, Rodrigo Rivas Costa
<rodrigorivascosta@xxxxxxxxx> wrote:
> On Wed, Feb 28, 2018 at 09:21:15PM +0200, Andy Shevchenko wrote:
>> On Wed, Feb 28, 2018 at 8:43 PM, Rodrigo Rivas Costa
>> <rodrigorivascosta@xxxxxxxxx> wrote:
>> > + if (input) {
>>
>> if (!input)
>> return;
>>
>> ?
> That was because of symmetry, because further patches add more objects.
> Then
> if (input)
> free(input);
> if (battery)
> free(battery);
> /* in the future *(
> if (input_gyro)
> free(input_gyro);
>
> Sure, the last one can do an early return, but you break symmetry.
The generic APIs when designed properly are NULL aware at freeing resources.
So, it should look like
free(input);
free(battery);
free(input_gyro);
>> > + if (steam) {
>> > + cancel_work_sync(&steam->work_connect);
>> > + steam_unregister(steam);
>>
>> > + hid_set_drvdata(hdev, NULL);
>>
>> Hmm.. Doesn't HID do this?
>
> Do you mean the hid_set_drvdata(hdev, NULL)? I'm not sure, I didn't see
> that on hid-core.c or hid-generic.c. And a call like this is done in
> many modules... so I did the same, just to be sure.
What you are looking for is, AFAIU:
drivers/base/dd.c:902: dev_set_drvdata(dev, NULL);
>>
>> > + }
>>
>> if (steam) {
>> ...
>> hid_hw_stop(hdev);
>> ...
>> } else {
>> hid_hw_stop(hdev);
>> }
>>
>> ?
>
> I have no real preference. Your version has two 'if', mine has two 'if'.
> What about:
>
> static void steam_remove(struct hid_device *hdev)
> {
> struct steam_device *steam = hid_get_drvdata(hdev);
>
> if (!steam) {
> hid_hw_stop(hdev);
> return;
> }
>
> if (steam->quirks & STEAM_QUIRK_WIRELESS) {
> hid_info(hdev, "Steam wireless receiver disconnected");
> hid_hw_close(hdev);
> }
> hid_hw_stop(hdev);
> cancel_work_sync(&steam->work_connect);
> steam_unregister(steam);
> hid_set_drvdata(hdev, NULL);
w/o this one.
> }
For me my version looks more compact to read, but at the end it's up to you.
Another option split if (steam) variant into helper, and thus
if (steam)
steam_non_null_device_remove();
else
hid_hw_stop();
But again, up to you (that's why question mark in the first place above).
--
With Best Regards,
Andy Shevchenko