Re: [PATCH 1/6] Revert "drm/prime: Unexport helpers for fd/handle conversion"

[Felix Kuehling <felix.kuehling@xxxxxxx>]

Hi Alex,

I'm about to push patches 1-3 to the rebased amd-staging-drm-next. It 
would be good to get patch 1 into drm-fixes so that Linux 6.6 will be 
the only kernel without these prime helpers. That would minimize the 
hassle for DKMS driver installations on future distros.

Thanks,
  Felix


On 2023-12-01 18:34, Felix Kuehling wrote:
> This reverts commit 71a7974ac7019afeec105a54447ae1dc7216cbb3.
>
> These helper functions are needed for KFD to export and import DMABufs
> the right way without duplicating the tracking of DMABufs associated with
> GEM objects while ensuring that move notifier callbacks are working as
> intended.
>
> Acked-by: Christian König <christian.koenig@xxxxxxx>
> Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> Acked-by: Daniel Vetter <daniel@xxxxxxxx>
> Signed-off-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
> ---
>   drivers/gpu/drm/drm_prime.c | 33 ++++++++++++++++++---------------
>   include/drm/drm_prime.h     |  7 +++++++
>   2 files changed, 25 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
> index 63b709a67471..834a5e28abbe 100644
> --- a/drivers/gpu/drm/drm_prime.c
> +++ b/drivers/gpu/drm/drm_prime.c
> @@ -278,7 +278,7 @@ 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
>    * @dev: drm_device to import into
>    * @file_priv: drm file-private structure
> @@ -292,9 +292,9 @@ EXPORT_SYMBOL(drm_gem_dmabuf_release);
>    *
>    * Returns 0 on success or a negative error code on failure.
>    */
> -static 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(struct drm_device *dev,
> +			       struct drm_file *file_priv, int prime_fd,
> +			       uint32_t *handle)
>   {
>   	struct dma_buf *dma_buf;
>   	struct drm_gem_object *obj;
> @@ -360,6 +360,7 @@ static 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);
>   
>   int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
>   				 struct drm_file *file_priv)
> @@ -408,7 +409,7 @@ static struct dma_buf *export_and_register_object(struct drm_device *dev,
>   	return dmabuf;
>   }
>   
> -/*
> +/**
>    * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
>    * @dev: dev to export the buffer from
>    * @file_priv: drm file-private structure
> @@ -421,10 +422,10 @@ static struct dma_buf *export_and_register_object(struct drm_device *dev,
>    * The actual exporting from GEM object to a dma-buf is done through the
>    * &drm_gem_object_funcs.export callback.
>    */
> -static 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)
> +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)
>   {
>   	struct drm_gem_object *obj;
>   	int ret = 0;
> @@ -506,6 +507,7 @@ static int drm_gem_prime_handle_to_fd(struct drm_device *dev,
>   
>   	return ret;
>   }
> +EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
>   
>   int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
>   				 struct drm_file *file_priv)
> @@ -864,9 +866,9 @@ EXPORT_SYMBOL(drm_prime_get_contiguous_size);
>    * @obj: GEM object to export
>    * @flags: flags like DRM_CLOEXEC and DRM_RDWR
>    *
> - * This is the implementation of the &drm_gem_object_funcs.export functions
> - * for GEM drivers using the PRIME helpers. It is used as the default for
> - * drivers that do not set their own.
> + * This is the implementation of the &drm_gem_object_funcs.export functions for GEM drivers
> + * using the PRIME helpers. It is used as the default in
> + * drm_gem_prime_handle_to_fd().
>    */
>   struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
>   				     int flags)
> @@ -962,9 +964,10 @@ EXPORT_SYMBOL(drm_gem_prime_import_dev);
>    * @dev: drm_device to import into
>    * @dma_buf: dma-buf object to import
>    *
> - * This is the implementation of the gem_prime_import functions for GEM
> - * drivers using the PRIME helpers. It is the default for drivers that do
> - * not set their own &drm_driver.gem_prime_import.
> + * This is the implementation of the gem_prime_import functions for GEM drivers
> + * using the PRIME helpers. Drivers can use this as their
> + * &drm_driver.gem_prime_import implementation. It is used as the default
> + * implementation in drm_gem_prime_fd_to_handle().
>    *
>    * Drivers must arrange to call drm_prime_gem_destroy() from their
>    * &drm_gem_object_funcs.free hook when using this function.
> diff --git a/include/drm/drm_prime.h b/include/drm/drm_prime.h
> index a7abf9f3e697..2a1d01e5b56b 100644
> --- a/include/drm/drm_prime.h
> +++ b/include/drm/drm_prime.h
> @@ -60,12 +60,19 @@ enum dma_data_direction;
>   
>   struct drm_device;
>   struct drm_gem_object;
> +struct drm_file;
>   
>   /* core prime functions */
>   struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
>   				      struct dma_buf_export_info *exp_info);
>   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_handle_to_fd(struct drm_device *dev,
> +			       struct drm_file *file_priv, uint32_t handle, uint32_t flags,
> +			       int *prime_fd);
> +
>   /* helper functions for exporting */
>   int drm_gem_map_attach(struct dma_buf *dma_buf,
>   		       struct dma_buf_attachment *attach);