[PATCH v4] drm/ioctl: Add a ioctl to label GEM objects

Daniel Vetter daniel at ffwll.ch
Tue Oct 22 09:30:52 UTC 2019


On Tue, Oct 22, 2019 at 10:58:02AM +0200, Rohan Garg wrote:
> Hey Daniel
> On lunes, 14 de octubre de 2019 10:59:38 (CEST) Daniel Vetter wrote:
> > On Fri, Oct 11, 2019 at 04:30:09PM +0200, Rohan Garg wrote:
> > > DRM_IOCTL_DUMB_SET_LABEL lets you label GEM objects, making it
> > > easier to debug issues in userspace applications.
> > > 
> > > Changes in v2:
> > >   - Hoist the IOCTL up into the drm_driver framework
> > > 
> > > Changes in v3:
> > >   - Introduce a drm_gem_set_label for drivers to use internally
> > >   
> > >     in order to label a GEM object
> > >   
> > >   - Hoist string copying up into the IOCTL
> > >   - Fix documentation
> > >   - Move actual gem labeling into drm_gem_adopt_label
> > > 
> > > Changes in v4:
> > >   - Refactor IOCTL call to only perform string duplication and move
> > >   
> > >     all gem lookup logic into GEM specific call
> > 
> > I still think we should just make this GEM-only and avoid the indirection.
> > Except if your userspace actually does run on vmwgfx, and you absolutely
> > want/need it to run there. Everything else is GEM-only.
> > -Daniel
> >
> 
> The plan for TTM drivers is to call drm_gem_adopt_label internally. So in 
> practice, there really won't be too much TTM specific code.
> 
> This approach also future proof's us to be able to label any handles, not just 
> GEM handle.

I don't expect we'll ever merge any non-gem drivers in the future anymore.
Hence this really only makes sense if vmwgfx wants it, that's the only
use-case for this generic-ism here. If vmwgfx doesn't have a use or jump
on board with this, imo better to just make this specific to gem and be
done.
-Daniel

> For the reasons above, I'd like to stick with my approach.
> 
> Cheers
> Rohan Garg
>  
> > > Signed-off-by: Rohan Garg <rohan.garg at collabora.com>
> > > ---
> > > 
> > >  drivers/gpu/drm/drm_gem.c      | 70 ++++++++++++++++++++++++++++++++++
> > >  drivers/gpu/drm/drm_internal.h |  8 ++++
> > >  drivers/gpu/drm/drm_ioctl.c    |  1 +
> > >  include/drm/drm_drv.h          | 16 ++++++++
> > >  include/drm/drm_gem.h          |  7 ++++
> > >  include/uapi/drm/drm.h         | 20 ++++++++++
> > >  6 files changed, 122 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> > > index 6854f5867d51..0fa4609b2817 100644
> > > --- a/drivers/gpu/drm/drm_gem.c
> > > +++ b/drivers/gpu/drm/drm_gem.c
> > > @@ -941,6 +941,71 @@ drm_gem_release(struct drm_device *dev, struct
> > > drm_file *file_private)> 
> > >  	idr_destroy(&file_private->object_idr);
> > >  
> > >  }
> > > 
> > > +int drm_dumb_set_label_ioctl(struct drm_device *dev,
> > > +				void *data, struct drm_file 
> *file_priv)
> > > +{
> > > +	char *label;
> > > +	struct drm_dumb_set_label_object *args = data;
> > > +	int ret = 0;
> > > +
> > > +	if (!args->len || !args->name)
> > > +		return -EINVAL;
> > > +
> > > +	if (!dev->driver->label)
> > > +		return -EOPNOTSUPP;
> > > +
> > > +	label = strndup_user(u64_to_user_ptr(args->name), args->len);
> > > +
> > > +	if (IS_ERR(label)) {
> > > +		ret = PTR_ERR(label);
> > > +		goto err;
> > > +	}
> > > +
> > > +	ret = dev->driver->label(dev, file_priv, args->handle, label);
> > > +
> > > +err:
> > > +	kfree(label);
> > > +	return ret;
> > > +}
> > > +
> > > +int drm_gem_set_label(struct drm_device *dev,
> > > +		       struct drm_file *file_priv,
> > > +			   uint32_t handle,
> > > +			   const char *label)
> > > +{
> > > +	struct drm_gem_object *gem_obj;
> > > +	int ret = 0;
> > > +
> > > +	gem_obj = drm_gem_object_lookup(file_priv, handle);
> > > +	if (!gem_obj) {
> > > +		DRM_DEBUG("Failed to look up GEM BO %d\n", handle);
> > > +		ret = -ENOENT;
> > > +		goto err;
> > > +	}
> > > +	drm_gem_adopt_label(gem_obj, label);
> > > +
> > > +err:
> > > +	drm_gem_object_put_unlocked(gem_obj);
> > > +	return ret;
> > > +}
> > > +EXPORT_SYMBOL(drm_gem_set_label);
> > > +
> > > +void drm_gem_adopt_label(struct drm_gem_object *gem_obj, const char
> > > *label) +{
> > > +	char *adopted_label = NULL;
> > > +
> > > +	if (label)
> > > +		adopted_label = kstrdup(label, GFP_KERNEL);
> > > +
> > > +	if (gem_obj->label) {
> > > +		kfree(gem_obj->label);
> > > +		gem_obj->label = NULL;
> > > +	}
> > > +
> > > +	gem_obj->label = adopted_label;
> > > +}
> > > +EXPORT_SYMBOL(drm_gem_adopt_label);
> > > +
> > > 
> > >  /**
> > >  
> > >   * drm_gem_object_release - release GEM buffer object resources
> > >   * @obj: GEM buffer object
> > > 
> > > @@ -958,6 +1023,11 @@ drm_gem_object_release(struct drm_gem_object *obj)
> > > 
> > >  	dma_resv_fini(&obj->_resv);
> > >  	drm_gem_free_mmap_offset(obj);
> > > 
> > > +
> > > +	if (obj->label) {
> > > +		kfree(obj->label);
> > > +		obj->label = NULL;
> > > +	}
> > > 
> > >  }
> > >  EXPORT_SYMBOL(drm_gem_object_release);
> > > 
> > > diff --git a/drivers/gpu/drm/drm_internal.h
> > > b/drivers/gpu/drm/drm_internal.h index 51a2055c8f18..cbc3f7b7fb9b 100644
> > > --- a/drivers/gpu/drm/drm_internal.h
> > > +++ b/drivers/gpu/drm/drm_internal.h
> > > @@ -137,6 +137,14 @@ int drm_gem_pin(struct drm_gem_object *obj);
> > > 
> > >  void drm_gem_unpin(struct drm_gem_object *obj);
> > >  void *drm_gem_vmap(struct drm_gem_object *obj);
> > >  void drm_gem_vunmap(struct drm_gem_object *obj, void *vaddr);
> > > 
> > > +int drm_dumb_set_label_ioctl(struct drm_device *dev,
> > > +			void *data,
> > > +			struct drm_file *file_priv);
> > > +int drm_gem_set_label(struct drm_device *dev,
> > > +			struct drm_file *file_priv,
> > > +			uint32_t handle,
> > > +			const char *label);
> > > +void drm_gem_adopt_label(struct drm_gem_object *gem_obj, const char
> > > *label);> 
> > >  /* drm_debugfs.c drm_debugfs_crc.c */
> > >  #if defined(CONFIG_DEBUG_FS)
> > > 
> > > diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
> > > index fcd728d7cf72..f34e1571d70f 100644
> > > --- a/drivers/gpu/drm/drm_ioctl.c
> > > +++ b/drivers/gpu/drm/drm_ioctl.c
> > > @@ -714,6 +714,7 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
> > > 
> > >  	DRM_IOCTL_DEF(DRM_IOCTL_MODE_LIST_LESSEES, 
> drm_mode_list_lessees_ioctl,
> > >  	DRM_MASTER), DRM_IOCTL_DEF(DRM_IOCTL_MODE_GET_LEASE,
> > >  	drm_mode_get_lease_ioctl, DRM_MASTER),
> > >  	DRM_IOCTL_DEF(DRM_IOCTL_MODE_REVOKE_LEASE, 
> drm_mode_revoke_lease_ioctl,
> > >  	DRM_MASTER),> 
> > > +	DRM_IOCTL_DEF(DRM_IOCTL_DUMB_SET_LABEL, drm_dumb_set_label_ioctl,
> > > DRM_RENDER_ALLOW),> 
> > >  };
> > >  
> > >  #define DRM_CORE_IOCTL_COUNT	ARRAY_SIZE( drm_ioctls )
> > > 
> > > diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
> > > index cf13470810a5..501a3924354a 100644
> > > --- a/include/drm/drm_drv.h
> > > +++ b/include/drm/drm_drv.h
> > > @@ -715,6 +715,22 @@ struct drm_driver {
> > > 
> > >  			    struct drm_device *dev,
> > >  			    uint32_t handle);
> > > 
> > > +	/**
> > > +	 * @label:
> > > +	 *
> > > +	 * This label's a buffer object.
> > > +	 *
> > > +	 * Called by the user via ioctl.
> > > +	 *
> > > +	 * Returns:
> > > +	 *
> > > +	 * Zero on success, negative errno on failure.
> > > +	 */
> > > +	int (*label)(struct drm_device *dev,
> > > +				struct drm_file *file_priv,
> > > +				uint32_t handle,
> > > +				char *label);
> > > +
> > > 
> > >  	/**
> > >  	
> > >  	 * @gem_vm_ops: Driver private ops for this object
> > >  	 *
> > > 
> > > diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
> > > index 6aaba14f5972..f801c054e972 100644
> > > --- a/include/drm/drm_gem.h
> > > +++ b/include/drm/drm_gem.h
> > > @@ -237,6 +237,13 @@ struct drm_gem_object {
> > > 
> > >  	 */
> > >  	
> > >  	int name;
> > > 
> > > +	/**
> > > +	 * @label:
> > > +	 *
> > > +	 * Label for this object, should be a human readable string.
> > > +	 */
> > > +	char *label;
> > > +
> > > 
> > >  	/**
> > >  	
> > >  	 * @dma_buf:
> > >  	 *
> > > 
> > > diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
> > > index 8a5b2f8f8eb9..309c3c091385 100644
> > > --- a/include/uapi/drm/drm.h
> > > +++ b/include/uapi/drm/drm.h
> > > @@ -626,6 +626,25 @@ struct drm_gem_open {
> > > 
> > >  	__u64 size;
> > >  
> > >  };
> > > 
> > > +/** struct drm_dumb_set_label_object - ioctl argument for labelling BOs.
> > > + *
> > > + * This label's a BO with a userspace label
> > > + *
> > > + */
> > > +struct drm_dumb_set_label_object {
> > > +	/** Handle for the object being labelled. */
> > > +	__u32 handle;
> > > +
> > > +	/** Label and label length.
> > > +	 *  len includes the trailing NUL.
> > > +	 */
> > > +	__u32 len;
> > > +	__u64 name;
> > > +
> > > +	/** Flags */
> > > +	int flags;
> > > +};
> > > +
> > > 
> > >  #define DRM_CAP_DUMB_BUFFER		0x1
> > >  #define DRM_CAP_VBLANK_HIGH_CRTC	0x2
> > >  #define DRM_CAP_DUMB_PREFERRED_DEPTH	0x3
> > > 
> > > @@ -946,6 +965,7 @@ extern "C" {
> > > 
> > >  #define DRM_IOCTL_SYNCOBJ_QUERY		DRM_IOWR(0xCB, struct
> > >  drm_syncobj_timeline_array) #define
> > >  DRM_IOCTL_SYNCOBJ_TRANSFER	DRM_IOWR(0xCC, struct drm_syncobj_transfer)
> > >  #define DRM_IOCTL_SYNCOBJ_TIMELINE_SIGNAL	DRM_IOWR(0xCD, struct
> > >  drm_syncobj_timeline_array)> 
> > > +#define DRM_IOCTL_DUMB_SET_LABEL      DRM_IOWR(0xCE, struct
> > > drm_dumb_set_label_object)> 
> > >  /**
> > >  
> > >   * Device specific ioctls should only be in their respective headers
> 
> 
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch


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