Re: [PATCH] drm/gpuvm: Rename 'map' to 'op' in drm_gpuvm_map_req

[Boris Brezillon <boris.brezillon@collabora.com>]

On Thu, 21 Aug 2025 22:25:06 +0530
"Ghimiray, Himal Prasad" <himal.prasad.ghimiray@intel.com> wrote:

> On 21-08-2025 19:05, Danilo Krummrich wrote:
> > On Thu Aug 21, 2025 at 3:01 PM CEST, Boris Brezillon wrote:  
> >> On Thu, 21 Aug 2025 14:55:06 +0200
> >> "Danilo Krummrich" <dakr@kernel.org> wrote:
> >>  
> >>> On Thu Aug 21, 2025 at 1:25 PM CEST, Boris Brezillon wrote:  
> >>>> On Thu, 21 Aug 2025 13:01:46 +0200
> >>>> Boris Brezillon <boris.brezillon@collabora.com> wrote:  
> >>>>> On a second thought, I'm now wondering why we need drm_gpuvm_map_req in
> >>>>> the first place. It would kinda make sense if it was containing an
> >>>>>
> >>>>> 	bool madvise;
> >>>>>
> >>>>> field, so you don't have to pass it around, but even then, I'm
> >>>>> wondering if we wouldn't be better off adding this field to
> >>>>> drm_gpuva_op_map instead and passing an drm_gpuva_op_map object to
> >>>>> the various map helpers (like Danilo suggested in his review of the
> >>>>> REPEATED mode series Caterina sent).  
> >>>>
> >>>> More on that: the very reason I introduced drm_gpuvm_map_req in the
> >>>> first place is so we have a clear differentiation between an overall
> >>>> map request and the sub-operations that are created to fulfill it.
> >>>> Looks like this was not a concern for Danilo and he was happy with us
> >>>> using _op_map for this.
> >>>>
> >>>> The other reason we might want to add drm_gpuvm_map_req is so that
> >>>> information we only need while splitting a req don't pollute
> >>>> drm_gpuva_op_map. Given I was going to pass the flags to the driver's
> >>>> callback anyway (meaning it's needed at the op_map level), and given
> >>>> you're passing madvise as a separate bool argument to various helpers
> >>>> (_map_req just contains the op, not the madvise bool), I don't think
> >>>> this aspect matters.  
> >>>
> >>> Good catch! Indeed, when Himal picked up your struct drm_gpuvm_map_req patch,
> >>> there were additional flags included in the structure. Now that it is
> >>> essentially a transparent wrapper, I prefer to use struct drm_gpuva_op_map
> >>> directly.
> >>>
> >>> However, given that you still have patches in flight that will add a flags field
> >>> to struct drm_gpuvm_map_req I think it's probably fine to introduce it right
> >>> away. Or did you drop this plan of adding those flags?  
> >>
> >> I need the flags field in the op_map too (so I can propagate it to the
> >> drm_gpuva object), so I'd rather go with an op_map object directly and
> >> kill drm_gpuvm_map_req now.  
> > 
> > In this case I agree, let's use struct drm_gpuva_op_map directly.  
> 
> According to the kernel documentation for the drm_gpuva_op_map 
> structure, it is intended to represent a single map operation generated 
> as the output of ops_create or the GPU VA manager. Using it as a direct 
> input to ops_create contradicts this definition.
> 
> For drm_gpuvm_sm_map_ops_create, the values align with those in 
> drm_gpuvm_map_req. However, this is not the case for 
> drm_gpuvm_madvise_ops_create.
> 
> If we plan to proceed with deprecating drm_gpuvm_map_req, we need to 
> clarify the fundamental definition of drm_gpuva_op_map:
> Should it represent a user-requested map, or an operation generated by 
> the GPU VA manager?

I would say, update the doc to reflect it can be used to pass a user
map request too, but I'll let Danilo make the final call. BTW,
embedding an op in _map_req is equivalent to saying the _op_map object
can describe a user map request to me :P.