Re: [PATCH v3 04/18] driver core: platform: Add driver dma ownership management

[Lu Baolu]

On 12/10/21 9:23 AM, Lu Baolu wrote:
> Hi Greg, Jason and Christoph,
>
> On 12/9/21 9:20 AM, Lu Baolu wrote:
> > On 12/7/21 9:16 PM, Jason Gunthorpe wrote:
> > > On Tue, Dec 07, 2021 at 10:57:25AM +0800, Lu Baolu wrote:
> > > > On 12/6/21 11:06 PM, Jason Gunthorpe wrote:
> > > > > On Mon, Dec 06, 2021 at 06:36:27AM -0800, Christoph Hellwig wrote:
> > > > > > I really hate the amount of boilerplate code that having this in each
> > > > > > bus type causes.
> > > > > +1
> > > > >
> > > > > I liked the first version of this series better with the code near
> > > > > really_probe().
> > > > >
> > > > > Can we go back to that with some device_configure_dma() wrapper
> > > > > condtionally called by really_probe as we discussed?
>
> [...]
>
> > diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> > index 68ea1f949daa..68ca5a579eb1 100644
> > --- a/drivers/base/dd.c
> > +++ b/drivers/base/dd.c
> > @@ -538,6 +538,32 @@ static int call_driver_probe(struct device *dev, 
> > struct device_driver *drv)
> >          return ret;
> >   }
> >
> > +static int device_dma_configure(struct device *dev, struct 
> > device_driver *drv)
> > +{
> > +       int ret;
> > +
> > +       if (!dev->bus->dma_configure)
> > +               return 0;
> > +
> > +       ret = dev->bus->dma_configure(dev);
> > +       if (ret)
> > +               return ret;
> > +
> > +       if (!drv->suppress_auto_claim_dma_owner)
> > +               ret = iommu_device_set_dma_owner(dev, 
> > DMA_OWNER_DMA_API, NULL);
> > +
> > +       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 +600,8 @@ 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;
> >
> >          ret = driver_sysfs_add(dev);
> >          if (ret) {
> > @@ -660,6 +683,8 @@ static int really_probe(struct device *dev, struct 
> > device_driver *drv)
> >          if (dev->bus)
> >                  blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
> >
> > BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
> > +
> > +       device_dma_cleanup(dev, drv);
> >   pinctrl_bind_failed:
> >          device_links_no_driver(dev);
> >          devres_release_all(dev);
> > @@ -1204,6 +1229,7 @@ static void __device_release_driver(struct 
> > device *dev, struct device *parent)
> >                  else if (drv->remove)
> >                          drv->remove(dev);
> >
> > +               device_dma_cleanup(dev, drv);
> >                  device_links_driver_cleanup(dev);
> >
> >                  devres_release_all(dev);
> > diff --git a/include/linux/device/driver.h 
> > b/include/linux/device/driver.h
> > index a498ebcf4993..374a3c2cc10d 100644
> > --- a/include/linux/device/driver.h
> > +++ b/include/linux/device/driver.h
> > @@ -100,6 +100,7 @@ struct device_driver {
> >          const char              *mod_name;      /* used for built-in 
> > modules */
> >
> >          bool suppress_bind_attrs;       /* disables bind/unbind via 
> > sysfs */
> > +       bool suppress_auto_claim_dma_owner;
> >          enum probe_type probe_type;
> >
> >          const struct of_device_id       *of_match_table;
>
> Does this work for you? Can I work towards this in the next version?

A kindly ping ... Is this heading the right direction? I need your
advice to move ahead. :-)

Best regards,
baolu