[PATCH 1/2] drm: call drm_gem_object_funcs.mmap with fake offset

[PATCH 1/2] drm: call drm_gem_object_funcs.mmap with fake offset

[Gerd Hoffmann]

The fake offset is going to stay, so change the calling convention for
drm_gem_object_funcs.mmap to include the fake offset.  Update all users
accordingly.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 include/drm/drm_gem.h                  | 4 +---
 drivers/gpu/drm/drm_gem.c              | 3 ---
 drivers/gpu/drm/drm_gem_shmem_helper.c | 3 +++
 drivers/gpu/drm/drm_prime.c            | 3 +++
 drivers/gpu/drm/ttm/ttm_bo_vm.c        | 7 -------
 5 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index 97a48165642c..0b375069cd48 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -159,9 +159,7 @@ struct drm_gem_object_funcs {
 	 *
 	 * The callback is used by by both drm_gem_mmap_obj() and
 	 * drm_gem_prime_mmap().  When @mmap is present @vm_ops is not
-	 * used, the @mmap callback must set vma->vm_ops instead. The @mmap
-	 * callback is always called with a 0 offset. The caller will remove
-	 * the fake offset as necessary.
+	 * used, the @mmap callback must set vma->vm_ops instead.
 	 */
 	int (*mmap)(struct drm_gem_object *obj, struct vm_area_struct *vma);
 
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 2f2b889096b0..56f42e0f2584 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1106,9 +1106,6 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
 		return -EINVAL;
 
 	if (obj->funcs && obj->funcs->mmap) {
-		/* Remove the fake offset */
-		vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
-
 		ret = obj->funcs->mmap(obj, vma);
 		if (ret)
 			return ret;
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 0810d3ef6961..a421a2eed48a 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -528,6 +528,9 @@ int drm_gem_shmem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
 	struct drm_gem_shmem_object *shmem;
 	int ret;
 
+	/* Remove the fake offset */
+	vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
+
 	shmem = to_drm_gem_shmem_obj(obj);
 
 	ret = drm_gem_shmem_get_pages(shmem);
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 0814211b0f3f..a9633bd241bb 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -714,6 +714,9 @@ int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
 	int ret;
 
 	if (obj->funcs && obj->funcs->mmap) {
+		/* Add the fake offset */
+		vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);
+
 		ret = obj->funcs->mmap(obj, vma);
 		if (ret)
 			return ret;
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index e6495ca2630b..3e8c3de91ae4 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -514,13 +514,6 @@ EXPORT_SYMBOL(ttm_bo_mmap);
 int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
 {
 	ttm_bo_get(bo);
-
-	/*
-	 * FIXME: &drm_gem_object_funcs.mmap is called with the fake offset
-	 * removed. Add it back here until the rest of TTM works without it.
-	 */
-	vma->vm_pgoff += drm_vma_node_start(&bo->base.vma_node);
-
 	ttm_bo_mmap_vma_setup(bo, vma);
 	return 0;
 }
-- 
2.18.1

[PATCH 2/2] drm: share address space for dma bufs

[Gerd Hoffmann]

Use the shared address space of the drm device (see drm_open() in
drm_file.c) for dma-bufs too.  That removes a difference betweem drm
device mmap vmas and dma-buf mmap vmas and fixes corner cases like
unmaps not working properly.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 drivers/gpu/drm/drm_prime.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index a9633bd241bb..c3fc341453c0 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -240,6 +240,7 @@ void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
 struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
 				      struct dma_buf_export_info *exp_info)
 {
+	struct drm_gem_object *obj = exp_info->priv;
 	struct dma_buf *dma_buf;
 
 	dma_buf = dma_buf_export(exp_info);
@@ -247,7 +248,8 @@ struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
 		return dma_buf;
 
 	drm_dev_get(dev);
-	drm_gem_object_get(exp_info->priv);
+	drm_gem_object_get(obj);
+	dma_buf->file->f_mapping = obj->dev->anon_inode->i_mapping;
 
 	return dma_buf;
 }
-- 
2.18.1

Re: [PATCH 1/2] drm: call drm_gem_object_funcs.mmap with fake offset

[Daniel Vetter]

On Thu, Nov 21, 2019 at 11:38:06AM +0100, Gerd Hoffmann wrote:
> The fake offset is going to stay, so change the calling convention for
> drm_gem_object_funcs.mmap to include the fake offset.  Update all users
> accordingly.

Please add to the commit message:

Note that this reverts 83b8a6f242ea ("drm/gem: Fix mmap fake offset
handling for drm_gem_object_funcs.mmap") and on top then adds the fake
offset to  drm_gem_prime_mmap to make sure all paths leading to
obj->funcs->mmap are consistent.

Fixes: 83b8a6f242ea ("drm/gem: Fix mmap fake offset handling for drm_gem_object_funcs.mmap")
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Herring <robh@kernel.org>

With that also Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
-Daniel
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  include/drm/drm_gem.h                  | 4 +---
>  drivers/gpu/drm/drm_gem.c              | 3 ---
>  drivers/gpu/drm/drm_gem_shmem_helper.c | 3 +++
>  drivers/gpu/drm/drm_prime.c            | 3 +++
>  drivers/gpu/drm/ttm/ttm_bo_vm.c        | 7 -------
>  5 files changed, 7 insertions(+), 13 deletions(-)
> 
> diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
> index 97a48165642c..0b375069cd48 100644
> --- a/include/drm/drm_gem.h
> +++ b/include/drm/drm_gem.h
> @@ -159,9 +159,7 @@ struct drm_gem_object_funcs {
>  	 *
>  	 * The callback is used by by both drm_gem_mmap_obj() and
>  	 * drm_gem_prime_mmap().  When @mmap is present @vm_ops is not
> -	 * used, the @mmap callback must set vma->vm_ops instead. The @mmap
> -	 * callback is always called with a 0 offset. The caller will remove
> -	 * the fake offset as necessary.
> +	 * used, the @mmap callback must set vma->vm_ops instead.
>  	 */
>  	int (*mmap)(struct drm_gem_object *obj, struct vm_area_struct *vma);
>  
> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> index 2f2b889096b0..56f42e0f2584 100644
> --- a/drivers/gpu/drm/drm_gem.c
> +++ b/drivers/gpu/drm/drm_gem.c
> @@ -1106,9 +1106,6 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
>  		return -EINVAL;
>  
>  	if (obj->funcs && obj->funcs->mmap) {
> -		/* Remove the fake offset */
> -		vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
> -
>  		ret = obj->funcs->mmap(obj, vma);
>  		if (ret)
>  			return ret;
> diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
> index 0810d3ef6961..a421a2eed48a 100644
> --- a/drivers/gpu/drm/drm_gem_shmem_helper.c
> +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
> @@ -528,6 +528,9 @@ int drm_gem_shmem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
>  	struct drm_gem_shmem_object *shmem;
>  	int ret;
>  
> +	/* Remove the fake offset */
> +	vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
> +
>  	shmem = to_drm_gem_shmem_obj(obj);
>  
>  	ret = drm_gem_shmem_get_pages(shmem);
> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
> index 0814211b0f3f..a9633bd241bb 100644
> --- a/drivers/gpu/drm/drm_prime.c
> +++ b/drivers/gpu/drm/drm_prime.c
> @@ -714,6 +714,9 @@ int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
>  	int ret;
>  
>  	if (obj->funcs && obj->funcs->mmap) {
> +		/* Add the fake offset */
> +		vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);
> +
>  		ret = obj->funcs->mmap(obj, vma);
>  		if (ret)
>  			return ret;
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> index e6495ca2630b..3e8c3de91ae4 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> @@ -514,13 +514,6 @@ EXPORT_SYMBOL(ttm_bo_mmap);
>  int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
>  {
>  	ttm_bo_get(bo);
> -
> -	/*
> -	 * FIXME: &drm_gem_object_funcs.mmap is called with the fake offset
> -	 * removed. Add it back here until the rest of TTM works without it.
> -	 */
> -	vma->vm_pgoff += drm_vma_node_start(&bo->base.vma_node);
> -
>  	ttm_bo_mmap_vma_setup(bo, vma);
>  	return 0;
>  }
> -- 
> 2.18.1
> 

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

Re: [PATCH 2/2] drm: share address space for dma bufs

[Daniel Vetter]

On Thu, Nov 21, 2019 at 11:38:07AM +0100, Gerd Hoffmann wrote:
> Use the shared address space of the drm device (see drm_open() in
> drm_file.c) for dma-bufs too.  That removes a difference betweem drm
> device mmap vmas and dma-buf mmap vmas and fixes corner cases like
> unmaps not working properly.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  drivers/gpu/drm/drm_prime.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
> index a9633bd241bb..c3fc341453c0 100644
> --- a/drivers/gpu/drm/drm_prime.c
> +++ b/drivers/gpu/drm/drm_prime.c
> @@ -240,6 +240,7 @@ void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
>  struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
>  				      struct dma_buf_export_info *exp_info)
>  {
> +	struct drm_gem_object *obj = exp_info->priv;
>  	struct dma_buf *dma_buf;
>  
>  	dma_buf = dma_buf_export(exp_info);
> @@ -247,7 +248,8 @@ struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
>  		return dma_buf;
>  
>  	drm_dev_get(dev);
> -	drm_gem_object_get(exp_info->priv);
> +	drm_gem_object_get(obj);
> +	dma_buf->file->f_mapping = obj->dev->anon_inode->i_mapping;

Can you pls also throw the change to amdgpu_gem_prime_export on top here?
Imo makes a lot more sense that way. With that added I'm happy to r-b.
-Daniel

>  
>  	return dma_buf;
>  }
> -- 
> 2.18.1
> 

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

Re: [PATCH 1/2] drm: call drm_gem_object_funcs.mmap with fake offset

[Daniel Vetter]

On Thu, Nov 21, 2019 at 02:52:59PM +0100, Daniel Vetter wrote:
> On Thu, Nov 21, 2019 at 11:38:06AM +0100, Gerd Hoffmann wrote:
> > The fake offset is going to stay, so change the calling convention for
> > drm_gem_object_funcs.mmap to include the fake offset.  Update all users
> > accordingly.
> 
> Please add to the commit message:
> 
> Note that this reverts 83b8a6f242ea ("drm/gem: Fix mmap fake offset
> handling for drm_gem_object_funcs.mmap") and on top then adds the fake
> offset to  drm_gem_prime_mmap to make sure all paths leading to
> obj->funcs->mmap are consistent.
> 
> Fixes: 83b8a6f242ea ("drm/gem: Fix mmap fake offset handling for drm_gem_object_funcs.mmap")
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Rob Herring <robh@kernel.org>
> 
> With that also Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Also added Rob to cc here.

Rob, can you pls take a look an ack? The sage took another turn :-)
-Daniel

> -Daniel
> > 
> > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> > ---
> >  include/drm/drm_gem.h                  | 4 +---
> >  drivers/gpu/drm/drm_gem.c              | 3 ---
> >  drivers/gpu/drm/drm_gem_shmem_helper.c | 3 +++
> >  drivers/gpu/drm/drm_prime.c            | 3 +++
> >  drivers/gpu/drm/ttm/ttm_bo_vm.c        | 7 -------
> >  5 files changed, 7 insertions(+), 13 deletions(-)
> > 
> > diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
> > index 97a48165642c..0b375069cd48 100644
> > --- a/include/drm/drm_gem.h
> > +++ b/include/drm/drm_gem.h
> > @@ -159,9 +159,7 @@ struct drm_gem_object_funcs {
> >  	 *
> >  	 * The callback is used by by both drm_gem_mmap_obj() and
> >  	 * drm_gem_prime_mmap().  When @mmap is present @vm_ops is not
> > -	 * used, the @mmap callback must set vma->vm_ops instead. The @mmap
> > -	 * callback is always called with a 0 offset. The caller will remove
> > -	 * the fake offset as necessary.
> > +	 * used, the @mmap callback must set vma->vm_ops instead.
> >  	 */
> >  	int (*mmap)(struct drm_gem_object *obj, struct vm_area_struct *vma);
> >  
> > diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> > index 2f2b889096b0..56f42e0f2584 100644
> > --- a/drivers/gpu/drm/drm_gem.c
> > +++ b/drivers/gpu/drm/drm_gem.c
> > @@ -1106,9 +1106,6 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
> >  		return -EINVAL;
> >  
> >  	if (obj->funcs && obj->funcs->mmap) {
> > -		/* Remove the fake offset */
> > -		vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
> > -
> >  		ret = obj->funcs->mmap(obj, vma);
> >  		if (ret)
> >  			return ret;
> > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
> > index 0810d3ef6961..a421a2eed48a 100644
> > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c
> > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
> > @@ -528,6 +528,9 @@ int drm_gem_shmem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
> >  	struct drm_gem_shmem_object *shmem;
> >  	int ret;
> >  
> > +	/* Remove the fake offset */
> > +	vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
> > +
> >  	shmem = to_drm_gem_shmem_obj(obj);
> >  
> >  	ret = drm_gem_shmem_get_pages(shmem);
> > diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
> > index 0814211b0f3f..a9633bd241bb 100644
> > --- a/drivers/gpu/drm/drm_prime.c
> > +++ b/drivers/gpu/drm/drm_prime.c
> > @@ -714,6 +714,9 @@ int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
> >  	int ret;
> >  
> >  	if (obj->funcs && obj->funcs->mmap) {
> > +		/* Add the fake offset */
> > +		vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);
> > +
> >  		ret = obj->funcs->mmap(obj, vma);
> >  		if (ret)
> >  			return ret;
> > diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> > index e6495ca2630b..3e8c3de91ae4 100644
> > --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
> > +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> > @@ -514,13 +514,6 @@ EXPORT_SYMBOL(ttm_bo_mmap);
> >  int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
> >  {
> >  	ttm_bo_get(bo);
> > -
> > -	/*
> > -	 * FIXME: &drm_gem_object_funcs.mmap is called with the fake offset
> > -	 * removed. Add it back here until the rest of TTM works without it.
> > -	 */
> > -	vma->vm_pgoff += drm_vma_node_start(&bo->base.vma_node);
> > -
> >  	ttm_bo_mmap_vma_setup(bo, vma);
> >  	return 0;
> >  }
> > -- 
> > 2.18.1
> > 
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

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

RE: [Intel-gfx] [PATCH 2/2] drm: share address space for dma bufs

[Ruhl, Michael J]

>-----Original Message-----
>From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Gerd
>Hoffmann
>Sent: Thursday, November 21, 2019 5:38 AM
>To: dri-devel@lists.freedesktop.org
>Cc: David Airlie <airlied@linux.ie>; intel-gfx@lists.freedesktop.org; open list
><linux-kernel@vger.kernel.org>; Maxime Ripard <mripard@kernel.org>; Gerd
>Hoffmann <kraxel@redhat.com>
>Subject: [Intel-gfx] [PATCH 2/2] drm: share address space for dma bufs
>
>Use the shared address space of the drm device (see drm_open() in
>drm_file.c) for dma-bufs too.  That removes a difference betweem drm
>device mmap vmas and dma-buf mmap vmas and fixes corner cases like
>unmaps not working properly.

Hi Gerd,

Just want to make sure I understand this...

So unmaps will not work correctly for mappings when a driver does a
drm_vma_node_unamp()?

I.e. the dmabuf mappings will not get cleaned up correctly?

This is a day one bug?

Thanks,

Mike


>Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
>---
> drivers/gpu/drm/drm_prime.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
>index a9633bd241bb..c3fc341453c0 100644
>--- a/drivers/gpu/drm/drm_prime.c
>+++ b/drivers/gpu/drm/drm_prime.c
>@@ -240,6 +240,7 @@ void drm_prime_destroy_file_private(struct
>drm_prime_file_private *prime_fpriv)
> struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
> 				      struct dma_buf_export_info *exp_info)
> {
>+	struct drm_gem_object *obj = exp_info->priv;
> 	struct dma_buf *dma_buf;
>
> 	dma_buf = dma_buf_export(exp_info);
>@@ -247,7 +248,8 @@ struct dma_buf *drm_gem_dmabuf_export(struct
>drm_device *dev,
> 		return dma_buf;
>
> 	drm_dev_get(dev);
>-	drm_gem_object_get(exp_info->priv);
>+	drm_gem_object_get(obj);
>+	dma_buf->file->f_mapping = obj->dev->anon_inode->i_mapping;
>
> 	return dma_buf;
> }
>--
>2.18.1
>
>_______________________________________________
>Intel-gfx mailing list
>Intel-gfx@lists.freedesktop.org
>https://lists.freedesktop.org/mailman/listinfo/intel-gfx

Re: [Intel-gfx] [PATCH 2/2] drm: share address space for dma bufs

[Gerd Hoffmann]

On Thu, Nov 21, 2019 at 04:42:10PM +0000, Ruhl, Michael J wrote:
> >-----Original Message-----
> >From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Gerd
> >Hoffmann
> >Sent: Thursday, November 21, 2019 5:38 AM
> >To: dri-devel@lists.freedesktop.org
> >Cc: David Airlie <airlied@linux.ie>; intel-gfx@lists.freedesktop.org; open list
> ><linux-kernel@vger.kernel.org>; Maxime Ripard <mripard@kernel.org>; Gerd
> >Hoffmann <kraxel@redhat.com>
> >Subject: [Intel-gfx] [PATCH 2/2] drm: share address space for dma bufs
> >
> >Use the shared address space of the drm device (see drm_open() in
> >drm_file.c) for dma-bufs too.  That removes a difference betweem drm
> >device mmap vmas and dma-buf mmap vmas and fixes corner cases like
> >unmaps not working properly.
> 
> Hi Gerd,
> 
> Just want to make sure I understand this...
> 
> So unmaps will not work correctly for mappings when a driver does a
> drm_vma_node_unamp()?

Completely removing the mapping (aka munmap syscall) works fine.
Zapping the pte's (using madvise(dontneed) for example) doesn't.

> This is a day one bug?

I guess so, but I'll leave that to others being active longer than me in
drm hacking to answer ...

cheers,
  Gerd