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

[Nicolin Chen <nicolinc@nvidia.com>]

On Fri, Oct 13, 2023 at 07:42:50PM +0800, Yi Liu wrote:
> On 2023/10/12 17:12, Yi Liu wrote:
> > On 2023/9/26 14:56, Tian, Kevin wrote:
> > > > From: Yi Liu <yi.l.liu@intel.com>
> > > > Sent: Thursday, September 21, 2023 3:51 PM
> > > > +
> > > > +/**
> > > > + * iommu_copy_user_data - Copy iommu driver specific user space data
> > > > + * @dst_data: Pointer to an iommu driver specific user data that is
> > > > defined
> > > > in
> > > > + *            include/uapi/linux/iommufd.h
> > > > + * @src_data: Pointer to a struct iommu_user_data for user space data info
> > > > + * @data_len: Length of current user data structure, i.e. sizeof(struct
> > > > _dst)
> > > > + * @min_len: Initial length of user data structure for backward
> > > > compatibility.
> > > > + *           This should be offsetofend using the last member in the
> > > > user data
> > > > + *           struct that was initially added to
> > > > include/uapi/linux/iommufd.h
> > > > + */
> > > > +static inline int iommu_copy_user_data(void *dst_data,
> > > > +                       const struct iommu_user_data *src_data,
> > > > +                       size_t data_len, size_t min_len)
> > > 
> > > iommu_copy_struct_from_user()?
> > > 
> > > btw given the confusion raised on how this would be used is it clearer
> > > to move it to the patch together with the 1st user?
> > 
> > sure. How about your opinion? @Nic.
> > 
> 
> after a second thinking, the first user of this helper is the patch to
> extend mock iommu driver. Is it suitable to introduce a common API together
> with selftest code?
> 
> https://lore.kernel.org/linux-iommu/20230921075138.124099-14-yi.l.liu@intel.com/

I feel no...

But I could separate iommu_copy_struct_from_user and its array
drivitive into an additional patch placed before the selftest
changes, so at least it would be closer to the first callers.

Thanks
Nic