From 207395da5a97035f06360638f0c2fcd92963ce95 Mon Sep 17 00:00:00 2001 From: Simon Ser Date: Thu, 2 Mar 2023 14:35:09 +0000 Subject: [PATCH] drm/prime: reject DMA-BUF attach when get_sg_table is missing MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Cc: Daniel Vetter Cc: Tian Tao Cc: Maxime Ripard Cc: Hans de Goede Acked-by: Thomas Zimmermann Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20230302143502.500661-1-contact@emersion.fr --- drivers/gpu/drm/drm_prime.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 149cd4ff6a3bb..d29dafce9bb0a 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -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); -- 2.30.2