Hi Jani,

I love your patch! Yet something to improve:

[auto build test ERROR on drm-intel/for-linux-next]
[cannot apply to drm-exynos/exynos-drm-next linus/master v5.4 v5.4-rc8 v5.4-rc7 next-20191203 v5.4 next-20191203]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Jani-Nikula/video-drm-etc-constify-fbops-in-struct-fb_info/20191204-055320
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: m68k-allmodconfig (attached as .config)
compiler: m68k-linux-gcc (GCC) 7.5.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.5.0 make.cross ARCH=m68k 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <redacted>

All errors (new ones prefixed by >>):

   drivers/video/fbdev/udlfb.c: In function 'dlfb_ops_release':

quoted

drivers/video/fbdev/udlfb.c:1040:24: error: assignment of member 'fb_mmap' in read-only object

      info->fbops->fb_mmap = dlfb_ops_mmap;
                           ^
--
   drivers/video/fbdev/smscufx.c: In function 'ufx_ops_release':

quoted

drivers/video/fbdev/smscufx.c:1173:24: error: assignment of member 'fb_mmap' in read-only object

      info->fbops->fb_mmap = ufx_ops_mmap;
                           ^
--
   drivers/video/fbdev/core/fb_defio.c: In function 'fb_deferred_io_init':

quoted

drivers/video/fbdev/core/fb_defio.c:209:23: error: assignment of member 'fb_mmap' in read-only object

     info->fbops->fb_mmap = fb_deferred_io_mmap;
                          ^
   drivers/video/fbdev/core/fb_defio.c: In function 'fb_deferred_io_cleanup':
   drivers/video/fbdev/core/fb_defio.c:240:23: error: assignment of member 'fb_mmap' in read-only object
     info->fbops->fb_mmap = NULL;
                          ^

vim +/fb_mmap +1040 drivers/video/fbdev/udlfb.c

33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1026  
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1027  /*
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1028   * Assumes caller is holding info->lock mutex (for open and release at least)
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1029   */
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1030  static int dlfb_ops_release(struct fb_info *info, int user)
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1031  {
7ea46206d1706b drivers/video/fbdev/udlfb.c   Ladislav Michl  2018-01-15  1032  	struct dlfb_data *dlfb = info->par;
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1033  
7ea46206d1706b drivers/video/fbdev/udlfb.c   Ladislav Michl  2018-01-15  1034  	dlfb->fb_count--;
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1035  
7ea46206d1706b drivers/video/fbdev/udlfb.c   Ladislav Michl  2018-01-15  1036  	if ((dlfb->fb_count == 0) && (info->fbdefio)) {
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1037  		fb_deferred_io_cleanup(info);
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1038  		kfree(info->fbdefio);
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1039  		info->fbdefio = NULL;
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05 @1040  		info->fbops->fb_mmap = dlfb_ops_mmap;
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1041  	}
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1042  
5865889fe43194 drivers/video/fbdev/udlfb.c   Ladislav Michl  2018-01-16  1043  	dev_dbg(info->dev, "release, user=%d count=%d\n", user, dlfb->fb_count);
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1044  
33077b8d3042e0 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-09-05  1045  	return 0;
2469d5dbcafe06 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-02-15  1046  }
2469d5dbcafe06 drivers/staging/udlfb/udlfb.c Bernie Thompson 2010-02-15  1047  

:::::: The code at line 1040 was first introduced by commit
:::::: 33077b8d3042e01da61924973e372abe589ba297 staging: udlfb: revamp reference handling to insure successful shutdown

:::::: TO: Bernie Thompson [off-list ref]
:::::: CC: Greg Kroah-Hartman [off-list ref]

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0-DAY kernel test infrastructure                 Open Source Technology Center
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