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

Daniel Vetter
2020-10-02T13:04:56Z

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@suse.de>
> ---
> 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@ffwll.ch>
>
> --
> 2.28.0
>

--
Daniel Vetter
Software Engineer, Intel Corporation