Commit 207395da authored by Simon Ser's avatar Simon Ser
Browse files

drm/prime: reject DMA-BUF attach when get_sg_table is missing 



drm_gem_map_dma_buf() requires drm_gem_object_funcs.get_sg_table
to be implemented, or else WARNs.

Allow drivers to leave this hook unimplemented to implement purely
local DMA-BUFs (ie, DMA-BUFs which cannot be imported anywhere
else but the device which allocated them). In that case, reject
imports to other devices in drm_gem_map_attach().

v2: new patch

v3: use ENOSYS

Signed-off-by: default avatarSimon Ser <contact@emersion.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Tian Tao <tiantao6@hisilicon.com>
Cc: Maxime Ripard <maxime@cerno.tech>
Cc: Hans de Goede <hdegoede@redhat.com>
Acked-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230302143502.500661-1-contact@emersion.fr
parent f435b7ef

drivers/gpu/drm/drm_prime.c

+5 −1
Original line number Diff line number Diff line
@@ -544,7 +544,8 @@ int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data, 
 * Optional pinning of buffers is handled at dma-buf attach and detach time in

 * drm_gem_map_attach() and drm_gem_map_detach(). Backing storage itself is

 * handled by drm_gem_map_dma_buf() and drm_gem_unmap_dma_buf(), which relies on

 * &drm_gem_object_funcs.get_sg_table.

 * &drm_gem_object_funcs.get_sg_table. If &drm_gem_object_funcs.get_sg_table is

 * unimplemented, exports into another device are rejected.

 *

 * For kernel-internal access there's drm_gem_dmabuf_vmap() and

 * drm_gem_dmabuf_vunmap(). Userspace mmap support is provided by
@@ -583,6 +584,9 @@ int drm_gem_map_attach(struct dma_buf *dma_buf, 
{

	struct drm_gem_object *obj = dma_buf->priv;



	if (!obj->funcs->get_sg_table)

		return -ENOSYS;



	return drm_gem_pin(obj);

}

EXPORT_SYMBOL(drm_gem_map_attach);