Re: [PATCH v3 2/8] ttm: turn ttm_bo_device.vma_manager into a pointer

[Thomas HellstrÃm (VMware)]

On 8/8/19 2:02 PM, Daniel Vetter wrote:
> On Thu, Aug 08, 2019 at 12:35:21PM +0200, Gerd Hoffmann wrote:
> > On Thu, Aug 08, 2019 at 09:48:49AM +0000, Koenig, Christian wrote:
> > > Am 08.08.19 um 11:36 schrieb Gerd Hoffmann:
> > > > Rename the embedded struct vma_offset_manager, it is named _vma_manager
> > > > now.  ttm_bo_device.vma_manager is a pointer now, pointing to the
> > > > embedded ttm_bo_device._vma_manager by default.
> > > >
> > > > Add ttm_bo_device_init_with_vma_manager() function which allows to
> > > > initialize ttm with a different vma manager.
> > > Can't we go down the route of completely removing the vma_manager from
> > > TTM? ttm_bo_mmap() would get the BO as parameter instead.
> > It surely makes sense to target that.  This patch can be a first step
> > into that direction.  It allows gem and ttm to use the same
> > vma_offset_manager (see patch #3), which in turn makes various gem
> > functions work on ttm objects (see patch #4 for vram helpers).
> +1 on cleaning this up for good, at least long-term ...
>
> > > That would also make the verify_access callback completely superfluous
> > > and looks like a good step into the right direction of de-midlayering.
> > Hmm, right, noticed that too while working on another patch series.
> > Guess I'll try to merge those two and see where I end up ...
> ... but if it gets too invasive I'd vote for incremental changes. Even if
> we completely rip out the vma/mmap lookup stuff from ttm, we still need to
> keep a copy somewhere for vmwgfx. Or would the evil plan be the vmwgfx
> would use the gem mmap helpers too?

I don't think it would be too invasive. We could simply move 
ttm_bo_vm_lookup into a vmw_mmap.

/Thomas




> -Daniel