Re: [PATCH 4/5] HID: apple-ibridge: Add Apple iBridge HID driver for T1 chip.

[Life is hard, and then you die]

  Hi Jonathan,

On Sun, Feb 28, 2021 at 03:02:39PM +0000, Jonathan Cameron wrote:
> On Sat, 27 Feb 2021 17:26:42 -0800
> Ronald Tschal?r <ron...@innovation.ch> wrote:
[snip]
> > +#ifdef CONFIG_PM
> > +/**
> > + * appleib_forward_int_op() - Forward a hid-driver callback to all drivers 
> > on
> > + * all virtual HID devices attached to the given real HID device.
> > + * @hdev the real hid-device
> > + * @forward a function that calls the callback on the given driver
> > + * @args arguments for the forward function
> > + *
> > + * This is for callbacks that return a status as an int.
> > + *
> > + * Returns: 0 on success, or the first error returned by the @forward 
> > function.
> > + */
> > +static int appleib_forward_int_op(struct hid_device *hdev,
> > +                             int (*forward)(struct hid_driver *,
> > +                                            struct hid_device *, void *),
> > +                             void *args)
> > +{
> > +   struct appleib_hid_dev_info *hdev_info = hid_get_drvdata(hdev);
> > +   struct hid_device *sub_hdev;
> > +   int rc = 0;
> > +   int i;
> > +
> > +   for (i = 0; i < ARRAY_SIZE(hdev_info->sub_hdevs); i++) {
> > +           sub_hdev = hdev_info->sub_hdevs[i];
> > +           if (sub_hdev->driver) {
> > +                   rc = forward(sub_hdev->driver, sub_hdev, args);
> > +                   if (rc)
> > +                           break;
> 
> return rc; here would be cleaner.
> 
> > +           }
> > +
> > +           break;
> 
> This is unusual.  It's a for loop but as far as I can see only first iteration
> can ever run as we exit the loop at this break if we haven't done so earlier.
> What is the intent here?
> 
> > +   }
> > +
> > +   return rc;
> > +}

Ho boy, good catch! This is simply a mistake. As you say, it should
(and does now) read:

        for (i = 0; i < ARRAY_SIZE(hdev_info->sub_hdevs); i++) {
                sub_hdev = hdev_info->sub_hdevs[i];
                if (sub_hdev->driver) {
                        rc = forward(sub_hdev->driver, sub_hdev, args);
                        if (rc)
                                return rc;
                }
        }

        return rc;

Thanks.


  Cheers,

  Ronald