[PATCH] drm/etnaviv: Implement mmap as GEM object function

[Lucas Stach]

Am Donnerstag, dem 24.06.2021 um 10:58 +0200 schrieb Thomas Zimmermann:
> Moving the driver-specific mmap code into a GEM object function allows
> for using DRM helpers for various mmap callbacks.
> 
> The respective etnaviv functions are being removed. The file_operations
> structure fops is now being created by the helper macro
> DEFINE_DRM_GEM_FOPS().
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> ---
>  drivers/gpu/drm/etnaviv/etnaviv_drv.c       | 14 ++------------
>  drivers/gpu/drm/etnaviv/etnaviv_drv.h       |  3 ---
>  drivers/gpu/drm/etnaviv/etnaviv_gem.c       | 18 +++++-------------
>  drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c | 13 -------------
>  4 files changed, 7 insertions(+), 41 deletions(-)
> 
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
> index f0a07278ad04..7dcc6392792d 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
> @@ -468,17 +468,7 @@ static const struct drm_ioctl_desc etnaviv_ioctls[] = {
>  	ETNA_IOCTL(PM_QUERY_SIG, pm_query_sig, DRM_RENDER_ALLOW),
>  };
>  
> -static const struct file_operations fops = {
> -	.owner              = THIS_MODULE,
> -	.open               = drm_open,
> -	.release            = drm_release,
> -	.unlocked_ioctl     = drm_ioctl,
> -	.compat_ioctl       = drm_compat_ioctl,
> -	.poll               = drm_poll,
> -	.read               = drm_read,
> -	.llseek             = no_llseek,
> -	.mmap               = etnaviv_gem_mmap,
> -};
> +DEFINE_DRM_GEM_FOPS(fops);
>  
>  static const struct drm_driver etnaviv_drm_driver = {
>  	.driver_features    = DRIVER_GEM | DRIVER_RENDER,
> @@ -487,7 +477,7 @@ static const struct drm_driver etnaviv_drm_driver = {
>  	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
>  	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
>  	.gem_prime_import_sg_table = etnaviv_gem_prime_import_sg_table,
> -	.gem_prime_mmap     = etnaviv_gem_prime_mmap,
> +	.gem_prime_mmap     = drm_gem_prime_mmap,
>  #ifdef CONFIG_DEBUG_FS
>  	.debugfs_init       = etnaviv_debugfs_init,
>  #endif
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.h b/drivers/gpu/drm/etnaviv/etnaviv_drv.h
> index 003288ebd896..049ae87de9be 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.h
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.h
> @@ -47,12 +47,9 @@ struct etnaviv_drm_private {
>  int etnaviv_ioctl_gem_submit(struct drm_device *dev, void *data,
>  		struct drm_file *file);
>  
> -int etnaviv_gem_mmap(struct file *filp, struct vm_area_struct *vma);
>  int etnaviv_gem_mmap_offset(struct drm_gem_object *obj, u64 *offset);
>  struct sg_table *etnaviv_gem_prime_get_sg_table(struct drm_gem_object *obj);
>  int etnaviv_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
> -int etnaviv_gem_prime_mmap(struct drm_gem_object *obj,
> -			   struct vm_area_struct *vma);
>  struct drm_gem_object *etnaviv_gem_prime_import_sg_table(struct drm_device *dev,
>  	struct dma_buf_attachment *attach, struct sg_table *sg);
>  int etnaviv_gem_prime_pin(struct drm_gem_object *obj);
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
> index b8fa6ed3dd73..8f1b5af47dd6 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
> @@ -130,8 +130,7 @@ static int etnaviv_gem_mmap_obj(struct etnaviv_gem_object *etnaviv_obj,
>  {
>  	pgprot_t vm_page_prot;
>  
> -	vma->vm_flags &= ~VM_PFNMAP;
> -	vma->vm_flags |= VM_MIXEDMAP;
> +	vma->vm_flags |= VM_IO | VM_MIXEDMAP | VM_DONTEXPAND | VM_DONTDUMP;

I don't fully understand why this change is needed and the commit log
is silent about it. Excuse my ignorance, but can you please explain the
reasoning behind this change?

Regards,
Lucas

>  
>  	vm_page_prot = vm_get_page_prot(vma->vm_flags);
>  
> @@ -154,19 +153,11 @@ static int etnaviv_gem_mmap_obj(struct etnaviv_gem_object *etnaviv_obj,
>  	return 0;
>  }
>  
> -int etnaviv_gem_mmap(struct file *filp, struct vm_area_struct *vma)
> +static int etnaviv_gem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
>  {
> -	struct etnaviv_gem_object *obj;
> -	int ret;
> -
> -	ret = drm_gem_mmap(filp, vma);
> -	if (ret) {
> -		DBG("mmap failed: %d", ret);
> -		return ret;
> -	}
> +	struct etnaviv_gem_object *etnaviv_obj = to_etnaviv_bo(obj);
>  
> -	obj = to_etnaviv_bo(vma->vm_private_data);
> -	return obj->ops->mmap(obj, vma);
> +	return etnaviv_obj->ops->mmap(etnaviv_obj, vma);
>  }
>  
>  static vm_fault_t etnaviv_gem_fault(struct vm_fault *vmf)
> @@ -567,6 +558,7 @@ static const struct drm_gem_object_funcs etnaviv_gem_object_funcs = {
>  	.unpin = etnaviv_gem_prime_unpin,
>  	.get_sg_table = etnaviv_gem_prime_get_sg_table,
>  	.vmap = etnaviv_gem_prime_vmap,
> +	.mmap = etnaviv_gem_mmap,
>  	.vm_ops = &vm_ops,
>  };
>  
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
> index d741b1d735f7..6d8bed9c739d 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
> @@ -34,19 +34,6 @@ int etnaviv_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  	return 0;
>  }
>  
> -int etnaviv_gem_prime_mmap(struct drm_gem_object *obj,
> -			   struct vm_area_struct *vma)
> -{
> -	struct etnaviv_gem_object *etnaviv_obj = to_etnaviv_bo(obj);
> -	int ret;
> -
> -	ret = drm_gem_mmap_obj(obj, obj->size, vma);
> -	if (ret < 0)
> -		return ret;
> -
> -	return etnaviv_obj->ops->mmap(etnaviv_obj, vma);
> -}
> -
>  int etnaviv_gem_prime_pin(struct drm_gem_object *obj)
>  {
>  	if (!obj->import_attach) {