Re: [PATCH RFCv1 03/14] iommufd: Prepare for viommu structures and functions

Nicolin Chen
2024-05-13T02:35:45Z

On Sun, May 12, 2024 at 10:42:12AM -0300, Jason Gunthorpe wrote:
> On Fri, Apr 12, 2024 at 08:47:00PM -0700, Nicolin Chen wrote:
>
> > +static inline struct iommufd_object *___iommufd_object_alloc(size_t size)
> > +{
> > + struct iommufd_object *obj;
> > +
> > + obj = kzalloc(size, GFP_KERNEL_ACCOUNT);
> > + if (!obj)
> > + return ERR_PTR(-ENOMEM);
> > +
> > + /* Starts out bias'd by 1 until it is removed from the xarray */
> > + refcount_set(&obj->shortterm_users, 1);
> > + refcount_set(&obj->users, 1);
> > +
> > + /*
> > + * The allocation of an obj->id needs an ictx, so it has to be done
> > + * after this ___iommufd_object_alloc() callback.
> > + */
> > +
> > + return obj;
> > +}
>
> It is probably cleaner to just make the existing allocation work with
> a NULL ictx for this case? Then we can use the existing alloc
> functions.
>
> > +#define viommu_struct_alloc(name) \
> > + struct iommufd_##name *_iommufd_##name##_alloc(size_t size) \
> > + { \
> > + struct iommufd_object *obj; \
> > + if (WARN_ON(size < sizeof(struct iommufd_##name))) \
> > + return NULL; \
>
> Then here you'd just use the exisint container_of based flow with the
> driver sub struct name passed as the 'obj'

Yes. And then we can probably unwrap this macro too since it's
no long that verbose to duplicate in viommu/vqueue allocators.

Thanks
Nicolin