Re: [PATCH v4 02/13] driver core: Set DMA ownership during driver bind/unbind

[Lu Baolu]

Hi Greg,

On 12/22/21 8:47 PM, Greg Kroah-Hartman wrote:
> > +
> > +	return ret;
> > +}
> > +
> > +static void device_dma_cleanup(struct device *dev, struct device_driver *drv)
> > +{
> > +	if (!dev->bus->dma_configure)
> > +		return;
> > +
> > +	if (!drv->suppress_auto_claim_dma_owner)
> > +		iommu_device_release_dma_owner(dev, DMA_OWNER_DMA_API);
> > +}
> > +
> >   static int really_probe(struct device *dev, struct device_driver *drv)
> >   {
> >   	bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
> > @@ -574,11 +601,8 @@ static int really_probe(struct device *dev, struct device_driver *drv)
> >   	if (ret)
> >   		goto pinctrl_bind_failed;
> >   
> > -	if (dev->bus->dma_configure) {
> > -		ret = dev->bus->dma_configure(dev);
> > -		if (ret)
> > -			goto probe_failed;
> > -	}
> > +	if (device_dma_configure(dev, drv))
> > +		goto pinctrl_bind_failed;
> Are you sure you are jumping to the proper error path here?  It is not
> obvious why you changed this.

The error handling path in really_probe() seems a bit wrong. For
example,

 572         /* If using pinctrl, bind pins now before probing */
 573         ret = pinctrl_bind_pins(dev);
 574         if (ret)
 575                 goto pinctrl_bind_failed;

[...]

 663 pinctrl_bind_failed:
 664         device_links_no_driver(dev);
 665         devres_release_all(dev);
 666         arch_teardown_dma_ops(dev);
 667         kfree(dev->dma_range_map);
 668         dev->dma_range_map = NULL;
 669         driver_sysfs_remove(dev);
             ^^^^^^^^^^^^^^^^^^^^^^^^^
 670         dev->driver = NULL;
 671         dev_set_drvdata(dev, NULL);
 672         if (dev->pm_domain && dev->pm_domain->dismiss)
 673                 dev->pm_domain->dismiss(dev);
 674         pm_runtime_reinit(dev);
 675         dev_pm_set_driver_flags(dev, 0);
 676 done:
 677         return ret;

The driver_sysfs_remove() will be called even driver_sysfs_add() hasn't
been called yet. I can fix this in a separated patch if I didn't miss
anything.

Best regards,
baolu