[PATCH 3/3] drm/amdgpu: Move to gtt before cpu accesses dma buf.

[Dan Carpenter]

Hi Samuel,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on drm/drm-next]
[also build test WARNING on v4.15-rc7 next-20180110]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Samuel-Li/drm-amdgpu-allow-framebuffer-in-GART-memory-as-well/20180106-050432
base:   git://people.freedesktop.org/~airlied/linux.git drm-next

smatch warnings:
drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c:226 amdgpu_gem_prime_export() error: 'buf' dereferencing possible ERR_PTR()

# https://github.com/0day-ci/linux/commit/6aa2afecb5a3efc463d200023839399571404843
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout 6aa2afecb5a3efc463d200023839399571404843
vim +/buf +226 drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c

6aa2afecb5 Samuel Li       2018-01-04  211  
d38ceaf99e Alex Deucher    2015-04-20  212  struct dma_buf *amdgpu_gem_prime_export(struct drm_device *dev,
d38ceaf99e Alex Deucher    2015-04-20  213  					struct drm_gem_object *gobj,
d38ceaf99e Alex Deucher    2015-04-20  214  					int flags)
d38ceaf99e Alex Deucher    2015-04-20  215  {
d38ceaf99e Alex Deucher    2015-04-20  216  	struct amdgpu_bo *bo = gem_to_amdgpu_bo(gobj);
4b277247b1 Christian König 2017-11-13  217  	struct dma_buf *buf;
d38ceaf99e Alex Deucher    2015-04-20  218  
e1eb899b45 Christian König 2017-08-25  219  	if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm) ||
e1eb899b45 Christian König 2017-08-25  220  	    bo->flags & AMDGPU_GEM_CREATE_VM_ALWAYS_VALID)
d38ceaf99e Alex Deucher    2015-04-20  221  		return ERR_PTR(-EPERM);
d38ceaf99e Alex Deucher    2015-04-20  222  
4b277247b1 Christian König 2017-11-13  223  	buf = drm_gem_prime_export(dev, gobj, flags);
4b277247b1 Christian König 2017-11-13  224  	if (!IS_ERR(buf))
4b277247b1 Christian König 2017-11-13  225  		buf->file->f_mapping = dev->anon_inode->i_mapping;
6aa2afecb5 Samuel Li       2018-01-04 @226  	buf->ops = &amdgpu_dmabuf_ops;
6aa2afecb5 Samuel Li       2018-01-04  227  
4b277247b1 Christian König 2017-11-13  228  	return buf;
d38ceaf99e Alex Deucher    2015-04-20  229  }
6aa2afecb5 Samuel Li       2018-01-04  230  

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