[PATCH v4 1/3] drm/prime: Pass the right module owner through to dma_buf_export()

[Petri Latvala]

For the series:

Reviewed-by: Petri Latvala <petri.latvala at intel.com>

On 10/05/2016 03:21 PM, Chris Wilson wrote:
> dma_buf_export() adds a reference to the owning module to the dmabuf (to
> prevent the driver from being unloaded whilst a third party still refers
> to the dmabuf). However, drm_gem_prime_export() was passing its own
> THIS_MODULE (i.e. drm.ko) rather than the driver. Extract the right
> owner from the device->fops instead.
>
> v2: Use C99 initializers to zero out unset elements of
> dma_buf_export_info
> v3: Extract the right module from dev->fops.
>
> Testcase: igt/vgem_basic/unload
> Reported-by: Petri Latvala <petri.latvala at intel.com>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Petri Latvala <petri.latvala at intel.com>
> Cc: Christian König <christian.koenig at amd.com>
> Cc: stable at vger.kernel.org
> Tested-by: Petri Latvala <petri.latvala at intel.com>
> ---
>   drivers/gpu/drm/drm_prime.c | 17 ++++++++++-------
>   include/drm/drmP.h          |  3 ++-
>   2 files changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
> index 57201d68cf61..80907b34d857 100644
> --- a/drivers/gpu/drm/drm_prime.c
> +++ b/drivers/gpu/drm/drm_prime.c
> @@ -397,14 +397,17 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
>    * using the PRIME helpers.
>    */
>   struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
> -				     struct drm_gem_object *obj, int flags)
> +				     struct drm_gem_object *obj,
> +				     int flags)
>   {
> -	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> -
> -	exp_info.ops = &drm_gem_prime_dmabuf_ops;
> -	exp_info.size = obj->size;
> -	exp_info.flags = flags;
> -	exp_info.priv = obj;
> +	struct dma_buf_export_info exp_info = {
> +		.exp_name = KBUILD_MODNAME, /* white lie for debug */
> +		.owner = dev->driver->fops->owner,
> +		.ops = &drm_gem_prime_dmabuf_ops,
> +		.size = obj->size,
> +		.flags = flags,
> +		.priv = obj,
> +	};
>   
>   	if (dev->driver->gem_prime_res_obj)
>   		exp_info.resv = dev->driver->gem_prime_res_obj(obj);
> diff --git a/include/drm/drmP.h b/include/drm/drmP.h
> index 0e99669159c1..81fcd553edf7 100644
> --- a/include/drm/drmP.h
> +++ b/include/drm/drmP.h
> @@ -1012,7 +1012,8 @@ static inline int drm_debugfs_remove_files(const struct drm_info_list *files,
>   #endif
>   
>   extern struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
> -		struct drm_gem_object *obj, int flags);
> +					    struct drm_gem_object *obj,
> +					    int flags);
>   extern 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);