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: Simon 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: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230302143502.500661-1-contact@emersion.fr
* 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
{
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);