Re: [PATCH v3 3/4] i2c: designware: Use the correct name of device-managed function

Krzysztof Wilczyński
2021-02-16T17:47:08Z

Hi Dejin,

Thank you for all the changes, looks good!

You could improve the subject line, as it is very vague - what is the
new function name more correct? Was the other and/or the previous one
not correct? Seems like you are correcting a typo of sorts, rather than
introducing a new function in this file.

> Use the new function pcim_alloc_irq_vectors() to allocate IRQ vectors,
> the pcim_alloc_irq_vectors() function, an explicit device-managed
> version of pci_alloc_irq_vectors(). If pcim_enable_device() has been
> called before, then pci_alloc_irq_vectors() is actually
> a device-managed function. It is used here as a device-managed
> function, So replace it with pcim_alloc_irq_vectors().

The commit is good, but it could use some polish, so to speak.

A few suggestions to think about:

- What are we adding and/or changing, and why
- Why is using pcim_alloc_irq_vectors(), which is part
of the managed devices framework, a better alternative
to the pci_alloc_irq_vectors()
- And finally why this change allowed us to remove the
pci_free_irq_vectors()

> At the same time, simplify the error handling path.

The change simplifies the error handling path, how? A line of two which
explains how it has been achieved might help should someone reads the
commit message in the future.

[...]
> if (controller->setup) {
> r = controller->setup(pdev, controller);
> - if (r) {
> - pci_free_irq_vectors(pdev);
> + if (r)
> return r;
> - }
> }
>
> i2c_dw_adjust_bus_speed(dev);
> @@ -246,10 +244,8 @@ static int i2c_dw_pci_probe(struct pci_dev *pdev,
> i2c_dw_acpi_configure(&pdev->dev);
>
> r = i2c_dw_validate_speed(dev);
> - if (r) {
> - pci_free_irq_vectors(pdev);
> + if (r)
> return r;
> - }
>
> i2c_dw_configure(dev);
>
> @@ -269,10 +265,8 @@ static int i2c_dw_pci_probe(struct pci_dev *pdev,
> adap->nr = controller->bus_num;
>
> r = i2c_dw_probe(dev);
> - if (r) {
> - pci_free_irq_vectors(pdev);
> + if (r)
> return r;
> - }
>
> pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
> pm_runtime_use_autosuspend(&pdev->dev);
> @@ -292,7 +286,6 @@ static void i2c_dw_pci_remove(struct pci_dev *pdev)
>
> i2c_del_adapter(&dev->adapter);
> devm_free_irq(&pdev->dev, dev->irq, dev);
> - pci_free_irq_vectors(pdev);

If pcim_release() is called should the pci_driver's probe callback fail,
and I assume that this is precisely the case, then all of the above make
sense in the view of using pcim_alloc_irq_vectors().

Reviewed-by: Krzysztof Wilczyński <kw@linux.com>

Krzysztof