releases/6.6.26/drm-prime-unbreak-virtgpu-dma-buf-export.patch

   1 From 8634e267618934601c87bcfcd6a3fe2fb3973d16 Mon Sep 17 00:00:00 2001
   2 From: Sasha Levin <sashal@kernel.org>
   3 Date: Fri, 22 Mar 2024 14:48:01 -0700
   4 Subject: drm/prime: Unbreak virtgpu dma-buf export
   5
   6 From: Rob Clark <robdclark@chromium.org>
   7
   8 [ Upstream commit a4ec240f6b7c21cf846d10017c3ce423a0eae92c ]
   9
  10 virtgpu "vram" GEM objects do not implement obj->get_sg_table().  But
  11 they also don't use drm_gem_map_dma_buf().  In fact they may not even
  12 have guest visible pages.  But it is perfectly fine to export and share
  13 with other virtual devices.
  14
  15 Reported-by: Dominik Behr <dbehr@chromium.org>
  16 Fixes: 207395da5a97 ("drm/prime: reject DMA-BUF attach when get_sg_table is missing")
  17 Signed-off-by: Rob Clark <robdclark@chromium.org>
  18 Reviewed-by: Simon Ser <contact@emersion.fr>
  19 Signed-off-by: Simon Ser <contact@emersion.fr>
  20 Link: https://patchwork.freedesktop.org/patch/msgid/20240322214801.319975-1-robdclark@gmail.com
  21 Signed-off-by: Sasha Levin <sashal@kernel.org>
  22 ---
  23  drivers/gpu/drm/drm_prime.c | 7 ++++++-
  24  1 file changed, 6 insertions(+), 1 deletion(-)
  25
  26 diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
  27 index 7352bde299d54..03bd3c7bd0dc2 100644
  28 --- a/drivers/gpu/drm/drm_prime.c
  29 +++ b/drivers/gpu/drm/drm_prime.c
  30 @@ -582,7 +582,12 @@ int drm_gem_map_attach(struct dma_buf *dma_buf,
  31  {
  32         struct drm_gem_object *obj = dma_buf->priv;
  33
  34 -       if (!obj->funcs->get_sg_table)
  35 +       /*
  36 +        * drm_gem_map_dma_buf() requires obj->get_sg_table(), but drivers
  37 +        * that implement their own ->map_dma_buf() do not.
  38 +        */
  39 +       if (dma_buf->ops->map_dma_buf == drm_gem_map_dma_buf &&
  40 +           !obj->funcs->get_sg_table)
  41                 return -ENOSYS;
  42
  43         return drm_gem_pin(obj);
  44 --
  45 2.43.0
  46