Re: [PATCH v2 13/15] drm/amdgpu: Use mmu_range_insert instead of hmm_mirror

[Jason Gunthorpe <jgg@mellanox.com>]

On Tue, Oct 29, 2019 at 10:14:29PM +0000, Kuehling, Felix wrote:

> > +static const struct mmu_range_notifier_ops amdgpu_mn_hsa_ops = {
> > +	.invalidate = amdgpu_mn_invalidate_hsa,
> > +};
> > +
> > +static int amdgpu_mn_sync_pagetables(struct hmm_mirror *mirror,
> > +				     const struct mmu_notifier_range *update)
> >   {
> >   	struct amdgpu_mn *amn = container_of(mirror, struct amdgpu_mn, mirror);
> > -	unsigned long start = update->start;
> > -	unsigned long end = update->end;
> > -	bool blockable = mmu_notifier_range_blockable(update);
> > -	struct interval_tree_node *it;
> >   
> > -	/* notification is exclusive, but interval is inclusive */
> > -	end -= 1;
> > -
> > -	if (amdgpu_mn_read_lock(amn, blockable))
> > -		return -EAGAIN;
> > -
> > -	it = interval_tree_iter_first(&amn->objects, start, end);
> > -	while (it) {
> > -		struct amdgpu_mn_node *node;
> > -		struct amdgpu_bo *bo;
> > -
> > -		if (!blockable) {
> > -			amdgpu_mn_read_unlock(amn);
> > -			return -EAGAIN;
> > -		}
> > -
> > -		node = container_of(it, struct amdgpu_mn_node, it);
> > -		it = interval_tree_iter_next(it, start, end);
> > -
> > -		list_for_each_entry(bo, &node->bos, mn_list) {
> > -			struct kgd_mem *mem = bo->kfd_bo;
> > -
> > -			if (amdgpu_ttm_tt_affect_userptr(bo->tbo.ttm,
> > -							 start, end))
> > -				amdgpu_amdkfd_evict_userptr(mem, amn->mm);
> > -		}
> > -	}
> > -
> > -	amdgpu_mn_read_unlock(amn);
> > +	if (!mmu_notifier_range_blockable(update))
> > +		return false;
> 
> This should return -EAGAIN. Not sure it matters much, because this whole 
> function disappears in the next commit in the series. It seems to be 
> only vestigial at this point.

Right, the only reason it is still here is that I couldn't really tell
if this:

> > +	down_read(&amn->lock);
> > +	up_read(&amn->lock);
> >   	return 0;
> >   }

Was serving as the 'driver lock' in the hmm scheme... If not then the
whole thing should just be deleted at this point.

I fixed the EAGAIN though

Jason