Re: [PATCH v3 4/7] drm/gem: Update internal GEM vmap/vunmap interfaces to use struct dma_buf_map

[Daniel Vetter <daniel@xxxxxxxx>]

On Tue, Sep 29, 2020 at 05:14:34PM +0200, Thomas Zimmermann wrote:
> GEM's vmap and vunmap interfaces now wrap memory pointers in struct
> dma_buf_map.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> ---
>  drivers/gpu/drm/drm_client.c   | 18 +++++++++++-------
>  drivers/gpu/drm/drm_gem.c      | 28 ++++++++++++++--------------
>  drivers/gpu/drm/drm_internal.h |  5 +++--
>  drivers/gpu/drm/drm_prime.c    | 14 ++++----------
>  4 files changed, 32 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c
> index 495f47d23d87..ac0082bed966 100644
> --- a/drivers/gpu/drm/drm_client.c
> +++ b/drivers/gpu/drm/drm_client.c
> @@ -3,6 +3,7 @@
>   * Copyright 2018 Noralf Trønnes
>   */
>  
> +#include <linux/dma-buf-map.h>
>  #include <linux/list.h>
>  #include <linux/module.h>
>  #include <linux/mutex.h>
> @@ -304,7 +305,8 @@ drm_client_buffer_create(struct drm_client_dev *client, 
> u32 width, u32 height, u
>   */
>  void *drm_client_buffer_vmap(struct drm_client_buffer *buffer)
>  {
> -     void *vaddr;
> +     struct dma_buf_map map;
> +     int ret;
>  
>       if (buffer->vaddr)
>               return buffer->vaddr;
> @@ -317,13 +319,13 @@ void *drm_client_buffer_vmap(struct drm_client_buffer 
> *buffer)
>        * fd_install step out of the driver backend hooks, to make that
>        * final step optional for internal users.
>        */
> -     vaddr = drm_gem_vmap(buffer->gem);
> -     if (IS_ERR(vaddr))
> -             return vaddr;
> +     ret = drm_gem_vmap(buffer->gem, &map);
> +     if (ret)
> +             return ERR_PTR(ret);
>  
> -     buffer->vaddr = vaddr;
> +     buffer->vaddr = map.vaddr;
>  
> -     return vaddr;
> +     return map.vaddr;
>  }
>  EXPORT_SYMBOL(drm_client_buffer_vmap);
>  
> @@ -337,7 +339,9 @@ EXPORT_SYMBOL(drm_client_buffer_vmap);
>   */
>  void drm_client_buffer_vunmap(struct drm_client_buffer *buffer)
>  {
> -     drm_gem_vunmap(buffer->gem, buffer->vaddr);
> +     struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(buffer->vaddr);
> +
> +     drm_gem_vunmap(buffer->gem, &map);
>       buffer->vaddr = NULL;
>  }
>  EXPORT_SYMBOL(drm_client_buffer_vunmap);
> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> index 0c4a66dea5c2..f2b2f37d41c4 100644
> --- a/drivers/gpu/drm/drm_gem.c
> +++ b/drivers/gpu/drm/drm_gem.c
> @@ -1205,32 +1205,32 @@ void drm_gem_unpin(struct drm_gem_object *obj)
>               obj->funcs->unpin(obj);
>  }
>  
> -void *drm_gem_vmap(struct drm_gem_object *obj)
> +int drm_gem_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
> -     struct dma_buf_map map;
>       int ret;
>  
> -     if (!obj->funcs->vmap) {
> -             return ERR_PTR(-EOPNOTSUPP);
> +     if (!obj->funcs->vmap)
> +             return -EOPNOTSUPP;
>  
> -     ret = obj->funcs->vmap(obj, &map);
> +     ret = obj->funcs->vmap(obj, map);
>       if (ret)
> -             return ERR_PTR(ret);
> -     else if (dma_buf_map_is_null(&map))
> -             return ERR_PTR(-ENOMEM);
> +             return ret;
> +     else if (dma_buf_map_is_null(map))
> +             return -ENOMEM;
>  
> -     return map.vaddr;
> +     return 0;
>  }
>  
> -void drm_gem_vunmap(struct drm_gem_object *obj, void *vaddr)
> +void drm_gem_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
> -     struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(vaddr);
> -
> -     if (!vaddr)
> +     if (dma_buf_map_is_null(map))
>               return;
>  
>       if (obj->funcs->vunmap)
> -             obj->funcs->vunmap(obj, &map);
> +             obj->funcs->vunmap(obj, map);
> +
> +     /* Always set the mapping to NULL. Callers may rely on this. */
> +     dma_buf_map_clear(map);
>  }
>  
>  /**
> diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
> index b65865c630b0..58832d75a9bd 100644
> --- a/drivers/gpu/drm/drm_internal.h
> +++ b/drivers/gpu/drm/drm_internal.h
> @@ -33,6 +33,7 @@
>  
>  struct dentry;
>  struct dma_buf;
> +struct dma_buf_map;
>  struct drm_connector;
>  struct drm_crtc;
>  struct drm_framebuffer;
> @@ -187,8 +188,8 @@ void drm_gem_print_info(struct drm_printer *p, unsigned 
> int indent,
>  
>  int drm_gem_pin(struct drm_gem_object *obj);
>  void drm_gem_unpin(struct drm_gem_object *obj);
> -void *drm_gem_vmap(struct drm_gem_object *obj);
> -void drm_gem_vunmap(struct drm_gem_object *obj, void *vaddr);
> +int drm_gem_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
> +void drm_gem_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>  
>  /* drm_debugfs.c drm_debugfs_crc.c */
>  #if defined(CONFIG_DEBUG_FS)
> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
> index 89e2a2496734..cb8fbeeb731b 100644
> --- a/drivers/gpu/drm/drm_prime.c
> +++ b/drivers/gpu/drm/drm_prime.c
> @@ -667,21 +667,15 @@ EXPORT_SYMBOL(drm_gem_unmap_dma_buf);
>   *
>   * Sets up a kernel virtual mapping. This can be used as the 
> &dma_buf_ops.vmap
>   * callback. Calls into &drm_gem_object_funcs.vmap for device specific 
> handling.
> + * The kernel virtual address is returned in map.
>   *
> - * Returns the kernel virtual address or NULL on failure.
> + * Returns 0 on success or a negative errno code otherwise.
>   */
>  int drm_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct dma_buf_map *map)
>  {
>       struct drm_gem_object *obj = dma_buf->priv;
> -     void *vaddr;
>  
> -     vaddr = drm_gem_vmap(obj);
> -     if (IS_ERR(vaddr))
> -             return PTR_ERR(vaddr);
> -
> -     dma_buf_map_set_vaddr(map, vaddr);
> -
> -     return 0;
> +     return drm_gem_vmap(obj, map);
>  }
>  EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
>  
> @@ -697,7 +691,7 @@ void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, 
> struct dma_buf_map *map)
>  {
>       struct drm_gem_object *obj = dma_buf->priv;
>  
> -     drm_gem_vunmap(obj, map->vaddr);
> +     drm_gem_vunmap(obj, map);
>  }
>  EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);

Some of the transitional stuff disappearing!

Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
>  
> -- 
> 2.28.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch