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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: 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
This commit is contained in:
Simon Ser 2023-03-02 14:35:09 +00:00
parent f435b7ef3b
commit 207395da5a
1 changed files with 5 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/gpu/drm/drm_prime.c
View File

@ -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);