[PATCH 1/3] drm: add gem ttm helpers

[PATCH 1/3] drm: add gem ttm helpers

[Gerd Hoffmann]

Now with ttm_buffer_object being a subclass of drm_gem_object we can
easily lookup ttm_buffer_object for a given drm_gem_object, which in
turm allows to create common helper functions.  This patch starts off
with dump mmap helpers.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 include/drm/drm_gem_ttm_helper.h     | 27 +++++++++++++++
 drivers/gpu/drm/drm_gem_ttm_helper.c | 52 ++++++++++++++++++++++++++++
 drivers/gpu/drm/Kconfig              |  7 ++++
 drivers/gpu/drm/Makefile             |  3 ++
 4 files changed, 89 insertions(+)
 create mode 100644 include/drm/drm_gem_ttm_helper.h
 create mode 100644 drivers/gpu/drm/drm_gem_ttm_helper.c

diff --git a/include/drm/drm_gem_ttm_helper.h b/include/drm/drm_gem_ttm_helper.h
new file mode 100644
index 000000000000..2c6874190b17
--- /dev/null
+++ b/include/drm/drm_gem_ttm_helper.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef DRM_GEM_TTM_HELPER_H
+#define DRM_GEM_TTM_HELPER_H
+
+#include <drm/drm_gem.h>
+#include <drm/ttm/ttm_bo_api.h>
+#include <linux/kernel.h> /* for container_of() */
+
+/**
+ * Returns the container of type &struct ttm_buffer_object
+ * for field base.
+ * @gem:	the GEM object
+ * Returns:	The containing GEM VRAM object
+ */
+static inline struct ttm_buffer_object *drm_gem_ttm_of_gem(
+	struct drm_gem_object *gem)
+{
+	return container_of(gem, struct ttm_buffer_object, base);
+}
+
+u64 drm_gem_ttm_mmap_offset(struct ttm_buffer_object *bo);
+int drm_gem_ttm_driver_dumb_mmap_offset(struct drm_file *file,
+					struct drm_device *dev,
+					uint32_t handle, uint64_t *offset);
+
+#endif
diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c b/drivers/gpu/drm/drm_gem_ttm_helper.c
new file mode 100644
index 000000000000..b069bd0c4c94
--- /dev/null
+++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <drm/drm_gem_ttm_helper.h>
+
+/**
+ * drm_gem_ttm_mmap_offset() - Returns a GEM ttm object's mmap offset
+ * @gbo:	the GEM ttm object
+ *
+ * See drm_vma_node_offset_addr() for more information.
+ *
+ * Returns:
+ * The buffer object's offset for userspace mappings on success, or
+ * 0 if no offset is allocated.
+ */
+u64 drm_gem_ttm_mmap_offset(struct ttm_buffer_object *bo)
+{
+	return drm_vma_node_offset_addr(&bo->base.vma_node);
+}
+EXPORT_SYMBOL(drm_gem_ttm_mmap_offset);
+
+/**
+ * drm_gem_ttm_driver_dumb_mmap_offset() - \
+	Implements &struct drm_driver.dumb_mmap_offset
+ * @file:	DRM file pointer.
+ * @dev:	DRM device.
+ * @handle:	GEM handle
+ * @offset:	Returns the mapping's memory offset on success
+ *
+ * Returns:
+ * 0 on success, or
+ * a negative errno code otherwise.
+ */
+int drm_gem_ttm_driver_dumb_mmap_offset(struct drm_file *file,
+					 struct drm_device *dev,
+					 uint32_t handle, uint64_t *offset)
+{
+	struct drm_gem_object *gem;
+	struct ttm_buffer_object *bo;
+
+	gem = drm_gem_object_lookup(file, handle);
+	if (!gem)
+		return -ENOENT;
+
+	bo = drm_gem_ttm_of_gem(gem);
+	*offset = drm_gem_ttm_mmap_offset(bo);
+
+	drm_gem_object_put_unlocked(gem);
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_gem_ttm_driver_dumb_mmap_offset);
+
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index e6f40fb54c9a..f7b25519f95c 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -172,6 +172,13 @@ config DRM_VRAM_HELPER
 	help
 	  Helpers for VRAM memory management
 
+config DRM_TTM_HELPER
+	tristate
+	depends on DRM
+	select DRM_TTM
+	help
+	  Helpers for ttm-based gem objects
+
 config DRM_GEM_CMA_HELPER
 	bool
 	depends on DRM
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 10f8329a8b71..545c61d6528b 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -37,6 +37,9 @@ drm_vram_helper-y := drm_gem_vram_helper.o \
 		     drm_vram_mm_helper.o
 obj-$(CONFIG_DRM_VRAM_HELPER) += drm_vram_helper.o
 
+drm_ttm_helper-y := drm_gem_ttm_helper.o
+obj-$(CONFIG_DRM_TTM_HELPER) += drm_ttm_helper.o
+
 drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_dsc.o drm_probe_helper.o \
 		drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \
 		drm_kms_helper_common.o drm_dp_dual_mode_helper.o \
-- 
2.18.1

Re: [PATCH 1/3] drm: add gem ttm helpers

[Daniel Vetter]

On Tue, Aug 06, 2019 at 03:34:52PM +0200, Gerd Hoffmann wrote:
> Now with ttm_buffer_object being a subclass of drm_gem_object we can
> easily lookup ttm_buffer_object for a given drm_gem_object, which in
> turm allows to create common helper functions.  This patch starts off
> with dump mmap helpers.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  include/drm/drm_gem_ttm_helper.h     | 27 +++++++++++++++
>  drivers/gpu/drm/drm_gem_ttm_helper.c | 52 ++++++++++++++++++++++++++++
>  drivers/gpu/drm/Kconfig              |  7 ++++
>  drivers/gpu/drm/Makefile             |  3 ++
>  4 files changed, 89 insertions(+)
>  create mode 100644 include/drm/drm_gem_ttm_helper.h
>  create mode 100644 drivers/gpu/drm/drm_gem_ttm_helper.c
> 
> diff --git a/include/drm/drm_gem_ttm_helper.h b/include/drm/drm_gem_ttm_helper.h
> new file mode 100644
> index 000000000000..2c6874190b17
> --- /dev/null
> +++ b/include/drm/drm_gem_ttm_helper.h
> @@ -0,0 +1,27 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +
> +#ifndef DRM_GEM_TTM_HELPER_H
> +#define DRM_GEM_TTM_HELPER_H
> +
> +#include <drm/drm_gem.h>
> +#include <drm/ttm/ttm_bo_api.h>
> +#include <linux/kernel.h> /* for container_of() */
> +
> +/**
> + * Returns the container of type &struct ttm_buffer_object
> + * for field base.
> + * @gem:	the GEM object
> + * Returns:	The containing GEM VRAM object
> + */
> +static inline struct ttm_buffer_object *drm_gem_ttm_of_gem(
> +	struct drm_gem_object *gem)
> +{
> +	return container_of(gem, struct ttm_buffer_object, base);
> +}
> +
> +u64 drm_gem_ttm_mmap_offset(struct ttm_buffer_object *bo);
> +int drm_gem_ttm_driver_dumb_mmap_offset(struct drm_file *file,
> +					struct drm_device *dev,
> +					uint32_t handle, uint64_t *offset);
> +
> +#endif
> diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c b/drivers/gpu/drm/drm_gem_ttm_helper.c
> new file mode 100644
> index 000000000000..b069bd0c4c94
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
> @@ -0,0 +1,52 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +
> +#include <drm/drm_gem_ttm_helper.h>
> +
> +/**
> + * drm_gem_ttm_mmap_offset() - Returns a GEM ttm object's mmap offset
> + * @gbo:	the GEM ttm object
> + *
> + * See drm_vma_node_offset_addr() for more information.
> + *
> + * Returns:
> + * The buffer object's offset for userspace mappings on success, or
> + * 0 if no offset is allocated.
> + */
> +u64 drm_gem_ttm_mmap_offset(struct ttm_buffer_object *bo)
> +{
> +	return drm_vma_node_offset_addr(&bo->base.vma_node);

Why do we need a new one here, can't we use the existing gem
implementation for this (there really should only be one I hope, but I
didn't check).

> +}
> +EXPORT_SYMBOL(drm_gem_ttm_mmap_offset);
> +
> +/**
> + * drm_gem_ttm_driver_dumb_mmap_offset() - \
> +	Implements &struct drm_driver.dumb_mmap_offset
> + * @file:	DRM file pointer.
> + * @dev:	DRM device.
> + * @handle:	GEM handle
> + * @offset:	Returns the mapping's memory offset on success
> + *
> + * Returns:
> + * 0 on success, or
> + * a negative errno code otherwise.
> + */
> +int drm_gem_ttm_driver_dumb_mmap_offset(struct drm_file *file,
> +					 struct drm_device *dev,
> +					 uint32_t handle, uint64_t *offset)
> +{
> +	struct drm_gem_object *gem;
> +	struct ttm_buffer_object *bo;
> +
> +	gem = drm_gem_object_lookup(file, handle);
> +	if (!gem)
> +		return -ENOENT;
> +
> +	bo = drm_gem_ttm_of_gem(gem);
> +	*offset = drm_gem_ttm_mmap_offset(bo);
> +
> +	drm_gem_object_put_unlocked(gem);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_gem_ttm_driver_dumb_mmap_offset);

Same for this, you're just upcasting to ttm_bo and then downcasting to
gem_bo again ... I think just a series to roll out the existing gem
helpers everywhere should work?
-Daniel

> +
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index e6f40fb54c9a..f7b25519f95c 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -172,6 +172,13 @@ config DRM_VRAM_HELPER
>  	help
>  	  Helpers for VRAM memory management
>  
> +config DRM_TTM_HELPER
> +	tristate
> +	depends on DRM
> +	select DRM_TTM
> +	help
> +	  Helpers for ttm-based gem objects
> +
>  config DRM_GEM_CMA_HELPER
>  	bool
>  	depends on DRM
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 10f8329a8b71..545c61d6528b 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -37,6 +37,9 @@ drm_vram_helper-y := drm_gem_vram_helper.o \
>  		     drm_vram_mm_helper.o
>  obj-$(CONFIG_DRM_VRAM_HELPER) += drm_vram_helper.o
>  
> +drm_ttm_helper-y := drm_gem_ttm_helper.o
> +obj-$(CONFIG_DRM_TTM_HELPER) += drm_ttm_helper.o
> +
>  drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_dsc.o drm_probe_helper.o \
>  		drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \
>  		drm_kms_helper_common.o drm_dp_dual_mode_helper.o \
> -- 
> 2.18.1
> 

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

Re: [PATCH 1/3] drm: add gem ttm helpers

[Gerd Hoffmann]

> > +/**
> > + * drm_gem_ttm_mmap_offset() - Returns a GEM ttm object's mmap offset
> > + * @gbo:	the GEM ttm object
> > + *
> > + * See drm_vma_node_offset_addr() for more information.
> > + *
> > + * Returns:
> > + * The buffer object's offset for userspace mappings on success, or
> > + * 0 if no offset is allocated.
> > + */
> > +u64 drm_gem_ttm_mmap_offset(struct ttm_buffer_object *bo)
> > +{
> > +	return drm_vma_node_offset_addr(&bo->base.vma_node);
> 
> Why do we need a new one here, can't we use the existing gem
> implementation for this (there really should only be one I hope, but I
> didn't check).

Havn't found one.

But maybe we don't need this as separate function and can simply move
the drm_vma_node_offset_addr() call into
drm_gem_ttm_driver_dumb_mmap_offset().

> > +int drm_gem_ttm_driver_dumb_mmap_offset(struct drm_file *file,
> > +					 struct drm_device *dev,
> > +					 uint32_t handle, uint64_t *offset)
> > +{
> > +	struct drm_gem_object *gem;
> > +	struct ttm_buffer_object *bo;
> > +
> > +	gem = drm_gem_object_lookup(file, handle);
> > +	if (!gem)
> > +		return -ENOENT;
> > +
> > +	bo = drm_gem_ttm_of_gem(gem);
> > +	*offset = drm_gem_ttm_mmap_offset(bo);
> > +
> > +	drm_gem_object_put_unlocked(gem);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL(drm_gem_ttm_driver_dumb_mmap_offset);
> 
> Same for this, you're just upcasting to ttm_bo and then downcasting to
> gem_bo again ... I think just a series to roll out the existing gem
> helpers everywhere should work?

I don't think so.  drm_gem_dumb_map_offset() calls
drm_gem_create_mmap_offset(), which I think is not correct for ttm
objects because ttm_bo_init() handles vma_node initialization.

cheers,
  Gerd

Re: [PATCH 1/3] drm: add gem ttm helpers

[Daniel Vetter]

On Wed, Aug 7, 2019 at 9:29 AM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
> > > +/**
> > > + * drm_gem_ttm_mmap_offset() - Returns a GEM ttm object's mmap offset
> > > + * @gbo:   the GEM ttm object
> > > + *
> > > + * See drm_vma_node_offset_addr() for more information.
> > > + *
> > > + * Returns:
> > > + * The buffer object's offset for userspace mappings on success, or
> > > + * 0 if no offset is allocated.
> > > + */
> > > +u64 drm_gem_ttm_mmap_offset(struct ttm_buffer_object *bo)
> > > +{
> > > +   return drm_vma_node_offset_addr(&bo->base.vma_node);
> >
> > Why do we need a new one here, can't we use the existing gem
> > implementation for this (there really should only be one I hope, but I
> > didn't check).
>
> Havn't found one.

It got reverted out again:

commit 415d2e9e07574d3de63b8df77dc686e0ebf64865
Author: Rob Herring <robh@kernel.org>
Date:   Wed Jul 3 16:38:50 2019 -0600

    Revert "drm/gem: Rename drm_gem_dumb_map_offset() to drm_gem_map_offset()"


> But maybe we don't need this as separate function and can simply move
> the drm_vma_node_offset_addr() call into
> drm_gem_ttm_driver_dumb_mmap_offset().
>
> > > +int drm_gem_ttm_driver_dumb_mmap_offset(struct drm_file *file,
> > > +                                    struct drm_device *dev,
> > > +                                    uint32_t handle, uint64_t *offset)
> > > +{
> > > +   struct drm_gem_object *gem;
> > > +   struct ttm_buffer_object *bo;
> > > +
> > > +   gem = drm_gem_object_lookup(file, handle);
> > > +   if (!gem)
> > > +           return -ENOENT;
> > > +
> > > +   bo = drm_gem_ttm_of_gem(gem);
> > > +   *offset = drm_gem_ttm_mmap_offset(bo);
> > > +
> > > +   drm_gem_object_put_unlocked(gem);
> > > +
> > > +   return 0;
> > > +}
> > > +EXPORT_SYMBOL(drm_gem_ttm_driver_dumb_mmap_offset);
> >
> > Same for this, you're just upcasting to ttm_bo and then downcasting to
> > gem_bo again ... I think just a series to roll out the existing gem
> > helpers everywhere should work?
>
> I don't think so.  drm_gem_dumb_map_offset() calls
> drm_gem_create_mmap_offset(), which I think is not correct for ttm
> objects because ttm_bo_init() handles vma_node initialization.

More code to unify first? This should work exactly the same way for
all gem based drivers I think ... Only tricky bit is making sure
vmwgfx keeps working correctly.
-Daniel

>
> cheers,
>   Gerd
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Re: [PATCH 1/3] drm: add gem ttm helpers

[Gerd Hoffmann]

  Hi,

> > > Same for this, you're just upcasting to ttm_bo and then downcasting to
> > > gem_bo again ... I think just a series to roll out the existing gem
> > > helpers everywhere should work?
> >
> > I don't think so.  drm_gem_dumb_map_offset() calls
> > drm_gem_create_mmap_offset(), which I think is not correct for ttm
> > objects because ttm_bo_init() handles vma_node initialization.
> 
> More code to unify first? This should work exactly the same way for
> all gem based drivers I think ... Only tricky bit is making sure
> vmwgfx keeps working correctly.

Yea.  Unifying on the gem way of doing things isn't going to work very
well.  We would have to keep the current way of doing things in the ttm
code, wrapped into "if (ttm_bo_uses_embedded_gem_object()) { ... }", to
not break vmwgfx.

So adding gem ttm helpers (where gem+ttm drivers can opt-in) looked like
the better way of handling this to me ...

cheers,
  Gerd

Re: [PATCH 1/3] drm: add gem ttm helpers

[Daniel Vetter]

On Wed, Aug 7, 2019 at 12:36 PM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
>   Hi,
>
> > > > Same for this, you're just upcasting to ttm_bo and then downcasting to
> > > > gem_bo again ... I think just a series to roll out the existing gem
> > > > helpers everywhere should work?
> > >
> > > I don't think so.  drm_gem_dumb_map_offset() calls
> > > drm_gem_create_mmap_offset(), which I think is not correct for ttm
> > > objects because ttm_bo_init() handles vma_node initialization.
> >
> > More code to unify first? This should work exactly the same way for
> > all gem based drivers I think ... Only tricky bit is making sure
> > vmwgfx keeps working correctly.
>
> Yea.  Unifying on the gem way of doing things isn't going to work very
> well.  We would have to keep the current way of doing things in the ttm
> code, wrapped into "if (ttm_bo_uses_embedded_gem_object()) { ... }", to
> not break vmwgfx.
>
> So adding gem ttm helpers (where gem+ttm drivers can opt-in) looked like
> the better way of handling this to me ...

Ok I looked again, and your ttm version seems to exactly match
drm_gem_dumb_map_offset(), which we almost called
drm_gem_map_offset(). And could do that again by undoing that revert.
So I'm not seeing how a generic version for this stuff here wouldn't
also work for ttm ... Ofc if vmwgfx does something else they can keep
their own specific dumb map_offset implementation.

What am I missing?
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Re: [PATCH 1/3] drm: add gem ttm helpers

[Gerd Hoffmann]

  Hi,

> > > > I don't think so.  drm_gem_dumb_map_offset() calls
> > > > drm_gem_create_mmap_offset(), which I think is not correct for ttm
> > > > objects because ttm_bo_init() handles vma_node initialization.

> Ok I looked again, and your ttm version seems to exactly match
> drm_gem_dumb_map_offset(),

No.  The difference outlined above is still there.  See also v2 which
adds an comment saying so.

cheers,
  Gerd

Re: [PATCH 1/3] drm: add gem ttm helpers

[Daniel Vetter]

On Wed, Aug 07, 2019 at 01:51:33PM +0200, Gerd Hoffmann wrote:
>   Hi,
> 
> > > > > I don't think so.  drm_gem_dumb_map_offset() calls
> > > > > drm_gem_create_mmap_offset(), which I think is not correct for ttm
> > > > > objects because ttm_bo_init() handles vma_node initialization.
> 
> > Ok I looked again, and your ttm version seems to exactly match
> > drm_gem_dumb_map_offset(),
> 
> No.  The difference outlined above is still there.  See also v2 which
> adds an comment saying so.

Creating an mmap offset is idempotent. Otherwise the gem version would
already blow up real bad, since it's getting called multiple times by
userspace already.

So I still think ttm isn't special here, how did this blow up when you
tried?
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH 1/3] drm: add gem ttm helpers

[Sam Ravnborg]

Hi Gerd.

On Tue, Aug 06, 2019 at 03:34:52PM +0200, Gerd Hoffmann wrote:
> Now with ttm_buffer_object being a subclass of drm_gem_object we can
> easily lookup ttm_buffer_object for a given drm_gem_object, which in
> turm allows to create common helper functions.  This patch starts off
> with dump mmap helpers.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

One nit below.

> ---
>  include/drm/drm_gem_ttm_helper.h     | 27 +++++++++++++++
>  drivers/gpu/drm/drm_gem_ttm_helper.c | 52 ++++++++++++++++++++++++++++
>  drivers/gpu/drm/Kconfig              |  7 ++++
>  drivers/gpu/drm/Makefile             |  3 ++
>  4 files changed, 89 insertions(+)
>  create mode 100644 include/drm/drm_gem_ttm_helper.h
>  create mode 100644 drivers/gpu/drm/drm_gem_ttm_helper.c
> 
> diff --git a/include/drm/drm_gem_ttm_helper.h b/include/drm/drm_gem_ttm_helper.h
> new file mode 100644
> index 000000000000..2c6874190b17
> --- /dev/null
> +++ b/include/drm/drm_gem_ttm_helper.h
> @@ -0,0 +1,27 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +
> +#ifndef DRM_GEM_TTM_HELPER_H
> +#define DRM_GEM_TTM_HELPER_H
> +
> +#include <drm/drm_gem.h>
> +#include <drm/ttm/ttm_bo_api.h>
> +#include <linux/kernel.h> /* for container_of() */

The typical order of include files is:

#include <linux/*>

#include <drm/*>

So space between each block of includes and sort within each block.

The comment "/* for container_of() */" is not really useful for
anyone.

	Sam

Re: [PATCH 1/3] drm: add gem ttm helpers

[Sam Ravnborg]

Hi Gerd.

On Tue, Aug 06, 2019 at 03:34:52PM +0200, Gerd Hoffmann wrote:
> Now with ttm_buffer_object being a subclass of drm_gem_object we can
> easily lookup ttm_buffer_object for a given drm_gem_object, which in
> turm allows to create common helper functions.  This patch starts off
> with dump mmap helpers.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  include/drm/drm_gem_ttm_helper.h     | 27 +++++++++++++++
>  drivers/gpu/drm/drm_gem_ttm_helper.c | 52 ++++++++++++++++++++++++++++
>  drivers/gpu/drm/Kconfig              |  7 ++++
>  drivers/gpu/drm/Makefile             |  3 ++
>  4 files changed, 89 insertions(+)
>  create mode 100644 include/drm/drm_gem_ttm_helper.h
>  create mode 100644 drivers/gpu/drm/drm_gem_ttm_helper.c

You have made nice kernel-doc comments for the struct and the public
functions.
Could we plug this into the existing doc too so one can browse around.
This will also allow you to check for any syntax errors using 
"make htmldocs"
(I spotted  one gbo versus bo mismatch)

A small DOC section in the top of drm_gem_ttm_helper.c
would also be nice. Just a few lines that introduce the purpose of this
file would cut it.

	Sam


> diff --git a/include/drm/drm_gem_ttm_helper.h b/include/drm/drm_gem_ttm_helper.h
> new file mode 100644
> index 000000000000..2c6874190b17
> --- /dev/null
> +++ b/include/drm/drm_gem_ttm_helper.h
> @@ -0,0 +1,27 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +
> +#ifndef DRM_GEM_TTM_HELPER_H
> +#define DRM_GEM_TTM_HELPER_H
> +
> +#include <drm/drm_gem.h>
> +#include <drm/ttm/ttm_bo_api.h>
> +#include <linux/kernel.h> /* for container_of() */
> +
> +/**
> + * Returns the container of type &struct ttm_buffer_object
> + * for field base.
> + * @gem:	the GEM object
> + * Returns:	The containing GEM VRAM object
> + */
> +static inline struct ttm_buffer_object *drm_gem_ttm_of_gem(
> +	struct drm_gem_object *gem)
> +{
> +	return container_of(gem, struct ttm_buffer_object, base);
> +}
> +
> +u64 drm_gem_ttm_mmap_offset(struct ttm_buffer_object *bo);
> +int drm_gem_ttm_driver_dumb_mmap_offset(struct drm_file *file,
> +					struct drm_device *dev,
> +					uint32_t handle, uint64_t *offset);
> +
> +#endif
> diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c b/drivers/gpu/drm/drm_gem_ttm_helper.c
> new file mode 100644
> index 000000000000..b069bd0c4c94
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
> @@ -0,0 +1,52 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +
> +#include <drm/drm_gem_ttm_helper.h>
> +
> +/**
> + * drm_gem_ttm_mmap_offset() - Returns a GEM ttm object's mmap offset
> + * @gbo:	the GEM ttm object
> + *
> + * See drm_vma_node_offset_addr() for more information.
> + *
> + * Returns:
> + * The buffer object's offset for userspace mappings on success, or
> + * 0 if no offset is allocated.
> + */
> +u64 drm_gem_ttm_mmap_offset(struct ttm_buffer_object *bo)
> +{
> +	return drm_vma_node_offset_addr(&bo->base.vma_node);
> +}
> +EXPORT_SYMBOL(drm_gem_ttm_mmap_offset);
> +
> +/**
> + * drm_gem_ttm_driver_dumb_mmap_offset() - \
> +	Implements &struct drm_driver.dumb_mmap_offset
> + * @file:	DRM file pointer.
> + * @dev:	DRM device.
> + * @handle:	GEM handle
> + * @offset:	Returns the mapping's memory offset on success
> + *
> + * Returns:
> + * 0 on success, or
> + * a negative errno code otherwise.
> + */
> +int drm_gem_ttm_driver_dumb_mmap_offset(struct drm_file *file,
> +					 struct drm_device *dev,
> +					 uint32_t handle, uint64_t *offset)
> +{
> +	struct drm_gem_object *gem;
> +	struct ttm_buffer_object *bo;
> +
> +	gem = drm_gem_object_lookup(file, handle);
> +	if (!gem)
> +		return -ENOENT;
> +
> +	bo = drm_gem_ttm_of_gem(gem);
> +	*offset = drm_gem_ttm_mmap_offset(bo);
> +
> +	drm_gem_object_put_unlocked(gem);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_gem_ttm_driver_dumb_mmap_offset);
> +
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index e6f40fb54c9a..f7b25519f95c 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -172,6 +172,13 @@ config DRM_VRAM_HELPER
>  	help
>  	  Helpers for VRAM memory management
>  
> +config DRM_TTM_HELPER
> +	tristate
> +	depends on DRM
> +	select DRM_TTM
> +	help
> +	  Helpers for ttm-based gem objects
> +
>  config DRM_GEM_CMA_HELPER
>  	bool
>  	depends on DRM
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 10f8329a8b71..545c61d6528b 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -37,6 +37,9 @@ drm_vram_helper-y := drm_gem_vram_helper.o \
>  		     drm_vram_mm_helper.o
>  obj-$(CONFIG_DRM_VRAM_HELPER) += drm_vram_helper.o
>  
> +drm_ttm_helper-y := drm_gem_ttm_helper.o
> +obj-$(CONFIG_DRM_TTM_HELPER) += drm_ttm_helper.o
> +
>  drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_dsc.o drm_probe_helper.o \
>  		drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \
>  		drm_kms_helper_common.o drm_dp_dual_mode_helper.o \
> -- 
> 2.18.1
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

[PATCH 2/3] drm/vram: switch vram helpers to use the new ttm helpers.

[Gerd Hoffmann]

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 include/drm/drm_gem_vram_helper.h             |  7 +--
 drivers/gpu/drm/drm_gem_vram_helper.c         | 48 -------------------
 .../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c   |  2 +-
 drivers/gpu/drm/Kconfig                       |  1 +
 4 files changed, 4 insertions(+), 54 deletions(-)

diff --git a/include/drm/drm_gem_vram_helper.h b/include/drm/drm_gem_vram_helper.h
index ac217d768456..fe4a1d5a35de 100644
--- a/include/drm/drm_gem_vram_helper.h
+++ b/include/drm/drm_gem_vram_helper.h
@@ -4,6 +4,7 @@
 #define DRM_GEM_VRAM_HELPER_H
 
 #include <drm/drm_gem.h>
+#include <drm/drm_gem_ttm_helper.h>
 #include <drm/ttm/ttm_bo_api.h>
 #include <drm/ttm/ttm_placement.h>
 #include <linux/kernel.h> /* for container_of() */
@@ -76,7 +77,6 @@ struct drm_gem_vram_object *drm_gem_vram_create(struct drm_device *dev,
 						unsigned long pg_align,
 						bool interruptible);
 void drm_gem_vram_put(struct drm_gem_vram_object *gbo);
-u64 drm_gem_vram_mmap_offset(struct drm_gem_vram_object *gbo);
 s64 drm_gem_vram_offset(struct drm_gem_vram_object *gbo);
 int drm_gem_vram_pin(struct drm_gem_vram_object *gbo, unsigned long pl_flag);
 int drm_gem_vram_unpin(struct drm_gem_vram_object *gbo);
@@ -110,9 +110,6 @@ extern const struct drm_vram_mm_funcs drm_gem_vram_mm_funcs;
 int drm_gem_vram_driver_dumb_create(struct drm_file *file,
 				    struct drm_device *dev,
 				    struct drm_mode_create_dumb *args);
-int drm_gem_vram_driver_dumb_mmap_offset(struct drm_file *file,
-					 struct drm_device *dev,
-					 uint32_t handle, uint64_t *offset);
 
 /**
  * define DRM_GEM_VRAM_DRIVER - default callback functions for \
@@ -123,7 +120,7 @@ int drm_gem_vram_driver_dumb_mmap_offset(struct drm_file *file,
  */
 #define DRM_GEM_VRAM_DRIVER \
 	.dumb_create		  = drm_gem_vram_driver_dumb_create, \
-	.dumb_map_offset	  = drm_gem_vram_driver_dumb_mmap_offset, \
+	.dumb_map_offset	  = drm_gem_ttm_driver_dumb_mmap_offset, \
 	.gem_prime_mmap		  = drm_gem_prime_mmap
 
 #endif
diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
index fd751078bae1..b78865055990 100644
--- a/drivers/gpu/drm/drm_gem_vram_helper.c
+++ b/drivers/gpu/drm/drm_gem_vram_helper.c
@@ -156,22 +156,6 @@ void drm_gem_vram_put(struct drm_gem_vram_object *gbo)
 }
 EXPORT_SYMBOL(drm_gem_vram_put);
 
-/**
- * drm_gem_vram_mmap_offset() - Returns a GEM VRAM object's mmap offset
- * @gbo:	the GEM VRAM object
- *
- * See drm_vma_node_offset_addr() for more information.
- *
- * Returns:
- * The buffer object's offset for userspace mappings on success, or
- * 0 if no offset is allocated.
- */
-u64 drm_gem_vram_mmap_offset(struct drm_gem_vram_object *gbo)
-{
-	return drm_vma_node_offset_addr(&gbo->bo.base.vma_node);
-}
-EXPORT_SYMBOL(drm_gem_vram_mmap_offset);
-
 /**
  * drm_gem_vram_offset() - \
 	Returns a GEM VRAM object's offset in video memory
@@ -511,38 +495,6 @@ int drm_gem_vram_driver_dumb_create(struct drm_file *file,
 }
 EXPORT_SYMBOL(drm_gem_vram_driver_dumb_create);
 
-/**
- * drm_gem_vram_driver_dumb_mmap_offset() - \
-	Implements &struct drm_driver.dumb_mmap_offset
- * @file:	DRM file pointer.
- * @dev:	DRM device.
- * @handle:	GEM handle
- * @offset:	Returns the mapping's memory offset on success
- *
- * Returns:
- * 0 on success, or
- * a negative errno code otherwise.
- */
-int drm_gem_vram_driver_dumb_mmap_offset(struct drm_file *file,
-					 struct drm_device *dev,
-					 uint32_t handle, uint64_t *offset)
-{
-	struct drm_gem_object *gem;
-	struct drm_gem_vram_object *gbo;
-
-	gem = drm_gem_object_lookup(file, handle);
-	if (!gem)
-		return -ENOENT;
-
-	gbo = drm_gem_vram_of_gem(gem);
-	*offset = drm_gem_vram_mmap_offset(gbo);
-
-	drm_gem_object_put_unlocked(gem);
-
-	return 0;
-}
-EXPORT_SYMBOL(drm_gem_vram_driver_dumb_mmap_offset);
-
 /*
  * PRIME helpers
  */
diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
index 2ae538835781..16fb10be4251 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
@@ -59,7 +59,7 @@ static struct drm_driver hibmc_driver = {
 	.major			= 1,
 	.minor			= 0,
 	.dumb_create            = hibmc_dumb_create,
-	.dumb_map_offset        = drm_gem_vram_driver_dumb_mmap_offset,
+	.dumb_map_offset        = drm_gem_ttm_driver_dumb_mmap_offset,
 	.gem_prime_mmap		= drm_gem_prime_mmap,
 	.irq_handler		= hibmc_drm_interrupt,
 };
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index f7b25519f95c..1be8ad30d8fe 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -169,6 +169,7 @@ config DRM_VRAM_HELPER
 	tristate
 	depends on DRM
 	select DRM_TTM
+	select DRM_TTM_HELPER
 	help
 	  Helpers for VRAM memory management
 
-- 
2.18.1

[PATCH 3/3] drm/qxl: switch qxl to use the new ttm helpers.

[Gerd Hoffmann]

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 drivers/gpu/drm/qxl/qxl_drv.h    |  4 +---
 drivers/gpu/drm/qxl/qxl_object.h |  5 -----
 drivers/gpu/drm/qxl/qxl_drv.c    |  2 +-
 drivers/gpu/drm/qxl/qxl_dumb.c   | 17 -----------------
 drivers/gpu/drm/qxl/qxl_ioctl.c  |  5 +++--
 drivers/gpu/drm/qxl/Kconfig      |  1 +
 6 files changed, 6 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/qxl/qxl_drv.h b/drivers/gpu/drm/qxl/qxl_drv.h
index 9e034c5fa87d..82efbe76062a 100644
--- a/drivers/gpu/drm/qxl/qxl_drv.h
+++ b/drivers/gpu/drm/qxl/qxl_drv.h
@@ -38,6 +38,7 @@
 #include <drm/drm_crtc.h>
 #include <drm/drm_encoder.h>
 #include <drm/drm_fb_helper.h>
+#include <drm/drm_gem_ttm_helper.h>
 #include <drm/drm_ioctl.h>
 #include <drm/drm_gem.h>
 #include <drm/qxl_drm.h>
@@ -347,9 +348,6 @@ int qxl_bo_kmap(struct qxl_bo *bo, void **ptr);
 int qxl_mode_dumb_create(struct drm_file *file_priv,
 			 struct drm_device *dev,
 			 struct drm_mode_create_dumb *args);
-int qxl_mode_dumb_mmap(struct drm_file *filp,
-		       struct drm_device *dev,
-		       uint32_t handle, uint64_t *offset_p);
 
 /* qxl ttm */
 int qxl_ttm_init(struct qxl_device *qdev);
diff --git a/drivers/gpu/drm/qxl/qxl_object.h b/drivers/gpu/drm/qxl/qxl_object.h
index 8ae54ba7857c..1f0316ebcfd0 100644
--- a/drivers/gpu/drm/qxl/qxl_object.h
+++ b/drivers/gpu/drm/qxl/qxl_object.h
@@ -58,11 +58,6 @@ static inline unsigned long qxl_bo_size(struct qxl_bo *bo)
 	return bo->tbo.num_pages << PAGE_SHIFT;
 }
 
-static inline u64 qxl_bo_mmap_offset(struct qxl_bo *bo)
-{
-	return drm_vma_node_offset_addr(&bo->tbo.base.vma_node);
-}
-
 static inline int qxl_bo_wait(struct qxl_bo *bo, u32 *mem_type,
 			      bool no_wait)
 {
diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
index c1802e01d9f6..18249110aa56 100644
--- a/drivers/gpu/drm/qxl/qxl_drv.c
+++ b/drivers/gpu/drm/qxl/qxl_drv.c
@@ -252,7 +252,7 @@ static struct drm_driver qxl_driver = {
 	.driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 
 	.dumb_create = qxl_mode_dumb_create,
-	.dumb_map_offset = qxl_mode_dumb_mmap,
+	.dumb_map_offset = drm_gem_ttm_driver_dumb_mmap_offset,
 #if defined(CONFIG_DEBUG_FS)
 	.debugfs_init = qxl_debugfs_init,
 #endif
diff --git a/drivers/gpu/drm/qxl/qxl_dumb.c b/drivers/gpu/drm/qxl/qxl_dumb.c
index 272d19b677d8..bd3b16a701a6 100644
--- a/drivers/gpu/drm/qxl/qxl_dumb.c
+++ b/drivers/gpu/drm/qxl/qxl_dumb.c
@@ -69,20 +69,3 @@ int qxl_mode_dumb_create(struct drm_file *file_priv,
 	args->handle = handle;
 	return 0;
 }
-
-int qxl_mode_dumb_mmap(struct drm_file *file_priv,
-		       struct drm_device *dev,
-		       uint32_t handle, uint64_t *offset_p)
-{
-	struct drm_gem_object *gobj;
-	struct qxl_bo *qobj;
-
-	BUG_ON(!offset_p);
-	gobj = drm_gem_object_lookup(file_priv, handle);
-	if (gobj == NULL)
-		return -ENOENT;
-	qobj = gem_to_qxl_bo(gobj);
-	*offset_p = qxl_bo_mmap_offset(qobj);
-	drm_gem_object_put_unlocked(gobj);
-	return 0;
-}
diff --git a/drivers/gpu/drm/qxl/qxl_ioctl.c b/drivers/gpu/drm/qxl/qxl_ioctl.c
index 8117a45b3610..b1cc38ed0ed4 100644
--- a/drivers/gpu/drm/qxl/qxl_ioctl.c
+++ b/drivers/gpu/drm/qxl/qxl_ioctl.c
@@ -67,8 +67,9 @@ static int qxl_map_ioctl(struct drm_device *dev, void *data,
 	struct qxl_device *qdev = dev->dev_private;
 	struct drm_qxl_map *qxl_map = data;
 
-	return qxl_mode_dumb_mmap(file_priv, &qdev->ddev, qxl_map->handle,
-				  &qxl_map->offset);
+	return drm_gem_ttm_driver_dumb_mmap_offset(file_priv, &qdev->ddev,
+						   qxl_map->handle,
+						   &qxl_map->offset);
 }
 
 struct qxl_reloc_info {
diff --git a/drivers/gpu/drm/qxl/Kconfig b/drivers/gpu/drm/qxl/Kconfig
index d0d691b31f4a..bfe90c7d17b2 100644
--- a/drivers/gpu/drm/qxl/Kconfig
+++ b/drivers/gpu/drm/qxl/Kconfig
@@ -3,6 +3,7 @@ config DRM_QXL
 	tristate "QXL virtual GPU"
 	depends on DRM && PCI && MMU
 	select DRM_KMS_HELPER
+	select DRM_TTM_HELPER
 	select DRM_TTM
 	select CRC32
 	help
-- 
2.18.1