RE: [RFC 11/20] iommu/iommufd: Add IOMMU_IOASID_ALLOC/FREE

[Liu, Yi L]

> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Sent: Wednesday, September 22, 2021 1:45 AM
> 
[...]
> > diff --git a/drivers/iommu/iommufd/iommufd.c
> b/drivers/iommu/iommufd/iommufd.c
> > index 641f199f2d41..4839f128b24a 100644
> > +++ b/drivers/iommu/iommufd/iommufd.c
> > @@ -24,6 +24,7 @@
> >  struct iommufd_ctx {
> >  	refcount_t refs;
> >  	struct mutex lock;
> > +	struct xarray ioasid_xa; /* xarray of ioasids */
> >  	struct xarray device_xa; /* xarray of bound devices */
> >  };
> >
> > @@ -42,6 +43,16 @@ struct iommufd_device {
> >  	u64 dev_cookie;
> >  };
> >
> > +/* Represent an I/O address space */
> > +struct iommufd_ioas {
> > +	int ioasid;
> 
> xarray id's should consistently be u32s everywhere.

sure. just one more check, this id is supposed to be returned to
userspace as the return value of ioctl(IOASID_ALLOC). That's why
I chose to use "int" as its prototype to make it aligned with the
return type of ioctl(). Based on this, do you think it's still better
to use "u32" here?

Regards,
Yi Liu

> Many of the same prior comments repeated here
>
> Jason