On Wed, Nov 06, 2019 at 02:24:29PM +0000, Chris Wilson wrote:
> Sometimes we need to create a struct file to wrap a drm_device, as it
> the user were to have opened /dev/dri/card0 but to do so anonymously
> (i.e. for internal use). Provide a utility method to create a struct
> file with the drm_device->driver.fops, that wrap the drm_device.
>
> v2: Restrict usage to selftests
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> ---
> drivers/gpu/drm/drm_file.c | 42 ++++++++++++++++++++++++++++++++++++++
> include/drm/drm_file.h | 3 +++
> 2 files changed, 45 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> index ea34bc991858..4d9385d1bf2d 100644
> --- a/drivers/gpu/drm/drm_file.c
> +++ b/drivers/gpu/drm/drm_file.c
> @@ -31,7 +31,9 @@
> * OTHER DEALINGS IN THE SOFTWARE.
> */
>
> +#include <linux/anon_inodes.h>
> #include <linux/dma-fence.h>
> +#include <linux/file.h>
> #include <linux/module.h>
> #include <linux/pci.h>
> #include <linux/poll.h>
> @@ -754,3 +756,43 @@ void drm_send_event(struct drm_device *dev, struct drm_pending_event *e)
> spin_unlock_irqrestore(&dev->event_lock, irqflags);
> }
> EXPORT_SYMBOL(drm_send_event);
> +
> +/**
> + * mock_drm_getfile - Create a new struct file for the drm device
> + * @minor: drm minor to wrap (e.g. #drm_device.primary)
> + * @flags: file creation mode (O_RDWR etc)
> + *
> + * This create a new struct file that wraps a DRM file context around a
> + * DRM minor. This mimicks userspace opening e.g. /dev/dri/card0, but without
> + * invoking userspace. The struct file may be operated on using its f_op
> + * (the drm_device.driver.fops) to mimick userspace operations, or be supplied
> + * to userspace facing functions as an internal/anonymous client.
> + *
> + * RETURNS:
> + * Pointer to newly created struct file, ERR_PTR on failure.
> + */
> +struct file *mock_drm_getfile(struct drm_minor *minor, unsigned int flags)
> +{
> + struct drm_device *dev = minor->dev;
> + struct drm_file *priv;
> + struct file *file;
> +
> + priv = drm_file_alloc(minor);
> + if (IS_ERR(priv))
> + return ERR_CAST(priv);
> +
> + file = anon_inode_getfile("drm", dev->driver->fops, priv, flags);
> + if (IS_ERR(file)) {
> + drm_file_free(priv);
> + return file;
> + }
> +
> + /* Everyone shares a single global address space */
> + file->f_mapping = dev->anon_inode->i_mapping;
> +
> + drm_dev_get(dev);
> + priv->filp = file;
> +
> + return file;
> +}
> +EXPORT_SYMBOL_FOR_TESTS_ONLY(mock_drm_getfile);
> diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
> index 67af60bb527a..8b099b347817 100644
> --- a/include/drm/drm_file.h
> +++ b/include/drm/drm_file.h
> @@ -42,6 +42,7 @@ struct dma_fence;
> struct drm_file;
> struct drm_device;
> struct device;
> +struct file;
>
> /*
> * FIXME: Not sure we want to have drm_minor here in the end, but to avoid
> @@ -387,4 +388,6 @@ void drm_event_cancel_free(struct drm_device *dev,
> void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e);
> void drm_send_event(struct drm_device *dev, struct drm_pending_event *e);
>
> +struct file *mock_drm_getfile(struct drm_minor *minor, unsigned int flags);
> +
> #endif /* _DRM_FILE_H_ */
> --
> 2.24.0
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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