[bug report] drm/amdgpu: move debugfs functions to their own file

[Dan Carpenter]

[ Not really a new bug, but moving the function makes it show up as a
  new bug.  - dan ]

Hello Alex Deucher,

The patch 75758255dc0f: "drm/amdgpu: move debugfs functions to their
own file" from Dec 14, 2017, leads to the following static checker
warning:

	drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c:696 amdgpu_debugfs_regs_init()
	warn: possible NULL dereference of 'ent'

drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
   677  int amdgpu_debugfs_regs_init(struct amdgpu_device *adev)
   678  {
   679          struct drm_minor *minor = adev->ddev->primary;
   680          struct dentry *ent, *root = minor->debugfs_root;
   681          unsigned i, j;
   682  
   683          for (i = 0; i < ARRAY_SIZE(debugfs_regs); i++) {
   684                  ent = debugfs_create_file(debugfs_regs_names[i],
   685                                            S_IFREG | S_IRUGO, root,
   686                                            adev, debugfs_regs[i]);
   687                  if (IS_ERR(ent)) {
   688                          for (j = 0; j < i; j++) {
   689                                  debugfs_remove(adev->debugfs_regs[i]);
   690                                  adev->debugfs_regs[i] = NULL;
   691                          }
   692                          return PTR_ERR(ent);
   693                  }
   694  
   695                  if (!i)
   696                          i_size_write(ent->d_inode, adev->rmmio_size);
					     ^^^^^^^^^^^^
debugfs_create_file() returns ERR_PTR(-ENODEV) if it's not enabled in
the .config or it returns a NULL pointer.

   697                  adev->debugfs_regs[i] = ent;
   698          }
   699  
   700          return 0;
   701  }

regards,
dan carpenter