[PATCH v2 3/8] drm/ttm: Add unampping of the entire device address space

[Daniel Vetter]

On Tue, Jun 23, 2020 at 01:00:02AM -0400, Andrey Grodzovsky wrote:
> 
> On 6/22/20 5:45 AM, Daniel Vetter wrote:
> > On Sun, Jun 21, 2020 at 02:03:03AM -0400, Andrey Grodzovsky wrote:
> > > Helper function to be used to invalidate all BOs CPU mappings
> > > once device is removed.
> > > 
> > > Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
> > This seems to be missing the code to invalidate all the dma-buf mmaps?
> > 
> > Probably needs more testcases if you're not yet catching this. Or am I
> > missing something, and we're exchanging the the address space also for
> > dma-buf?
> > -Daniel
> 
> 
> IMHO the device address space includes all user clients having a CPU view of
> the BO either from direct mapping though drm file or by  mapping through
> imported BO's FD.

Uh this is all very confusing and very much midlayer-y thanks to ttm.

I think a much better solution would be to have a core gem helper for
this (well not even gem really, this is core drm), which directly uses
drm_device->anon_inode->i_mapping.

Then
a) it clearly matches what drm_prime.c does on export
b) can be reused across all drivers, not just ttm

So much better.

What's more, we could then very easily make the generic
drm_dev_unplug_and_unmap helper I've talked about for the amdgpu patch,
which I think would be really neat&pretty.

Thoughts?
-Daniel

> 
> Andrey
> 
> 
> > 
> > > ---
> > >   drivers/gpu/drm/ttm/ttm_bo.c    | 8 ++++++--
> > >   include/drm/ttm/ttm_bo_driver.h | 7 +++++++
> > >   2 files changed, 13 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> > > index c5b516f..926a365 100644
> > > --- a/drivers/gpu/drm/ttm/ttm_bo.c
> > > +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> > > @@ -1750,10 +1750,14 @@ void ttm_bo_unmap_virtual(struct ttm_buffer_object *bo)
> > >   	ttm_bo_unmap_virtual_locked(bo);
> > >   	ttm_mem_io_unlock(man);
> > >   }
> > > -
> > > -
> > >   EXPORT_SYMBOL(ttm_bo_unmap_virtual);
> > > +void ttm_bo_unmap_virtual_address_space(struct ttm_bo_device *bdev)
> > > +{
> > > +	unmap_mapping_range(bdev->dev_mapping, 0, 0, 1);
> > > +}
> > > +EXPORT_SYMBOL(ttm_bo_unmap_virtual_address_space);
> > > +
> > >   int ttm_bo_wait(struct ttm_buffer_object *bo,
> > >   		bool interruptible, bool no_wait)
> > >   {
> > > diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
> > > index c9e0fd0..39ea44f 100644
> > > --- a/include/drm/ttm/ttm_bo_driver.h
> > > +++ b/include/drm/ttm/ttm_bo_driver.h
> > > @@ -601,6 +601,13 @@ int ttm_bo_device_init(struct ttm_bo_device *bdev,
> > >   void ttm_bo_unmap_virtual(struct ttm_buffer_object *bo);
> > >   /**
> > > + * ttm_bo_unmap_virtual_address_space
> > > + *
> > > + * @bdev: tear down all the virtual mappings for this device
> > > + */
> > > +void ttm_bo_unmap_virtual_address_space(struct ttm_bo_device *bdev);
> > > +
> > > +/**
> > >    * ttm_bo_unmap_virtual
> > >    *
> > >    * @bo: tear down the virtual mappings for this BO
> > > -- 
> > > 2.7.4
> > > 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch