Re: [PATCH v4 01/17] iommu: Add hwpt_type with user_data for domain_alloc_user op

[Yi Liu]

On 2023/10/11 00:58, Jason Gunthorpe wrote:
> On Thu, Sep 21, 2023 at 12:51:22AM -0700, Yi Liu wrote:
> > diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> > index 660dc1931dc9..12e12e5563e6 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -14,6 +14,7 @@
> >   #include <linux/err.h>
> >   #include <linux/of.h>
> >   #include <uapi/linux/iommu.h>
> > +#include <uapi/linux/iommufd.h>
>
> Oh we should definately avoid doing that!
>    
> Maybe this is a good moment to start a new header file exclusively for
> iommu drivers and core subsystem to include?
>
>   include/linux/iommu-driver.h
>
> ?
>
> Put iommu_copy_user_data() and  struct iommu_user_data in there
>
> Avoid this include in this file.

sure. btw. seems all the user of this API and structure are in the
drivers/iommu directory. can we just putting them in
drivers/iommu/iommu-priv.h?

> >   #define IOMMU_READ	(1 << 0)
> >   #define IOMMU_WRITE	(1 << 1)
> > @@ -227,6 +228,41 @@ struct iommu_iotlb_gather {
> >   	bool			queued;
> >   };
> >   
> > +/**
> > + * struct iommu_user_data - iommu driver specific user space data info
> > + * @uptr: Pointer to the user buffer for copy_from_user()
> > + * @len: The length of the user buffer in bytes
> > + *
> > + * A user space data is an uAPI that is defined in include/uapi/linux/iommufd.h
> > + * Both @uptr and @len should be just copied from an iommufd core uAPI structure
> > + */
> > +struct iommu_user_data {
> > +	void __user *uptr;
> > +	size_t len;
> > +};
>
> Put the "hwpt_type" in here and just call it type

I assume this is a change related to the above comment to avoid
including uapi/linux/iommufd.h. right?

Just one concern. There are other paths (like cache_invalidate of
this series and Nic's set_dev_data) uses this struct as well. I'm
a bit worrying if it is good to put type here as type is meaningful
for the domain_alloc_user path.

--
Regards,
Yi Liu