Re: [Intel-gfx] [PATCH 6/8] drm: Add drm_gem_prime_fd_to_handle_obj

["Iddamsetty, Aravind" <aravind.iddamsetty@intel.com>]

On 09-06-2023 17:41, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> 
> I need a new flavour of the drm_gem_prime_fd_to_handle helper, one which
> will return a reference to a newly created GEM objects (if created), in
> order to enable tracking of imported i915 GEM objects in the following
> patch.

instead of this what if we implement the open call back in i915

struct drm_gem_object_funcs {

        /**
         * @open:
         *
         * Called upon GEM handle creation.
         *
         * This callback is optional.
         */
        int (*open)(struct drm_gem_object *obj, struct drm_file *file);

which gets called whenever a handle(drm_gem_handle_create_tail) is
created and in the open we can check if to_intel_bo(obj)->base.dma_buf
then it is imported if not it is owned or created by it.

Thanks,
Aravind.

> 
> Minor code reshuffule and only trivial additions on top of
> drm_gem_prime_fd_to_handle.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> ---
>  drivers/gpu/drm/drm_prime.c | 41 ++++++++++++++++++++++++++++++++-----
>  include/drm/drm_prime.h     |  4 ++++
>  2 files changed, 40 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
> index d29dafce9bb0..ef75f67e3057 100644
> --- a/drivers/gpu/drm/drm_prime.c
> +++ b/drivers/gpu/drm/drm_prime.c
> @@ -284,11 +284,12 @@ void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
>  EXPORT_SYMBOL(drm_gem_dmabuf_release);
>  
>  /**
> - * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
> + * drm_gem_prime_fd_to_handle_obj - PRIME import function for GEM drivers
>   * @dev: drm_device to import into
>   * @file_priv: drm file-private structure
>   * @prime_fd: fd id of the dma-buf which should be imported
>   * @handle: pointer to storage for the handle of the imported buffer object
> + * @objp: optional pointer in which reference to created GEM object can be returned
>   *
>   * This is the PRIME import function which must be used mandatorily by GEM
>   * drivers to ensure correct lifetime management of the underlying GEM object.
> @@ -297,9 +298,10 @@ EXPORT_SYMBOL(drm_gem_dmabuf_release);
>   *
>   * Returns 0 on success or a negative error code on failure.
>   */
> -int drm_gem_prime_fd_to_handle(struct drm_device *dev,
> -			       struct drm_file *file_priv, int prime_fd,
> -			       uint32_t *handle)
> +int drm_gem_prime_fd_to_handle_obj(struct drm_device *dev,
> +				   struct drm_file *file_priv, int prime_fd,
> +				   uint32_t *handle,
> +				   struct drm_gem_object **objp)
>  {
>  	struct dma_buf *dma_buf;
>  	struct drm_gem_object *obj;
> @@ -336,7 +338,8 @@ int drm_gem_prime_fd_to_handle(struct drm_device *dev,
>  
>  	/* _handle_create_tail unconditionally unlocks dev->object_name_lock. */
>  	ret = drm_gem_handle_create_tail(file_priv, obj, handle);
> -	drm_gem_object_put(obj);
> +	if (!objp)
> +		drm_gem_object_put(obj);
>  	if (ret)
>  		goto out_put;
>  
> @@ -348,6 +351,9 @@ int drm_gem_prime_fd_to_handle(struct drm_device *dev,
>  
>  	dma_buf_put(dma_buf);
>  
> +	if (objp)
> +		*objp = obj;
> +
>  	return 0;
>  
>  fail:
> @@ -356,6 +362,8 @@ int drm_gem_prime_fd_to_handle(struct drm_device *dev,
>  	 */
>  	drm_gem_handle_delete(file_priv, *handle);
>  	dma_buf_put(dma_buf);
> +	if (objp)
> +		drm_gem_object_put(obj);
>  	return ret;
>  
>  out_unlock:
> @@ -365,6 +373,29 @@ int drm_gem_prime_fd_to_handle(struct drm_device *dev,
>  	dma_buf_put(dma_buf);
>  	return ret;
>  }
> +EXPORT_SYMBOL(drm_gem_prime_fd_to_handle_obj);
> +
> +/**
> + * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
> + * @dev: drm_device to import into
> + * @file_priv: drm file-private structure
> + * @prime_fd: fd id of the dma-buf which should be imported
> + * @handle: pointer to storage for the handle of the imported buffer object
> + *
> + * This is the PRIME import function which must be used mandatorily by GEM
> + * drivers to ensure correct lifetime management of the underlying GEM object.
> + * The actual importing of GEM object from the dma-buf is done through the
> + * &drm_driver.gem_prime_import driver callback.
> + *
> + * Returns 0 on success or a negative error code on failure.
> + */
> +int drm_gem_prime_fd_to_handle(struct drm_device *dev,
> +			       struct drm_file *file_priv, int prime_fd,
> +			       uint32_t *handle)
> +{
> +	return drm_gem_prime_fd_to_handle_obj(dev, file_priv, prime_fd, handle,
> +					      NULL);
> +}
>  EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
>  
>  int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
> diff --git a/include/drm/drm_prime.h b/include/drm/drm_prime.h
> index 2a1d01e5b56b..10d145ce6586 100644
> --- a/include/drm/drm_prime.h
> +++ b/include/drm/drm_prime.h
> @@ -69,6 +69,10 @@ void drm_gem_dmabuf_release(struct dma_buf *dma_buf);
>  
>  int drm_gem_prime_fd_to_handle(struct drm_device *dev,
>  			       struct drm_file *file_priv, int prime_fd, uint32_t *handle);
> +int drm_gem_prime_fd_to_handle_obj(struct drm_device *dev,
> +				   struct drm_file *file_priv, int prime_fd,
> +				   uint32_t *handle,
> +				   struct drm_gem_object **obj);
>  int drm_gem_prime_handle_to_fd(struct drm_device *dev,
>  			       struct drm_file *file_priv, uint32_t handle, uint32_t flags,
>  			       int *prime_fd);