[PATCH] fbdev: Fix incorrect page mapping clearance at fb_deferred_io_release()

[kernel test robot]

Hi Takashi,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.3-rc1 next-20230308]
[cannot apply to drm-misc/drm-misc-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Takashi-Iwai/fbdev-Fix-incorrect-page-mapping-clearance-at-fb_deferred_io_release/20230308-143749
patch link:    https://lore.kernel.org/r/20230308063628.15233-1-tiwai%40suse.de
patch subject: [PATCH] fbdev: Fix incorrect page mapping clearance at fb_deferred_io_release()
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20230308/202303081843.yyoyPjaN-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
reproduce (this is a W=1 build):
        # https://github.com/intel-lab-lkp/linux/commit/fe94468e5ddd91231f1624559f861fb8110163c3
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Takashi-Iwai/fbdev-Fix-incorrect-page-mapping-clearance-at-fb_deferred_io_release/20230308-143749
        git checkout fe94468e5ddd91231f1624559f861fb8110163c3
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/video/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp at intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303081843.yyoyPjaN-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/video/fbdev/core/fb_defio.c: In function 'fb_deferred_io_release_internal':
>> drivers/video/fbdev/core/fb_defio.c:317:32: warning: unused variable 'fbdefio' [-Wunused-variable]
     317 |         struct fb_deferred_io *fbdefio = info->fbdefio;
         |                                ^~~~~~~


vim +/fbdefio +317 drivers/video/fbdev/core/fb_defio.c

0b78f8bcf4951af drivers/video/fbdev/core/fb_defio.c Matthew Wilcox 2021-06-01  314  
fe94468e5ddd912 drivers/video/fbdev/core/fb_defio.c Takashi Iwai   2023-03-08  315  static void fb_deferred_io_release_internal(struct fb_info *info)
60b59beafba875a drivers/video/fb_defio.c            Jaya Kumar     2007-05-08  316  {
60b59beafba875a drivers/video/fb_defio.c            Jaya Kumar     2007-05-08 @317  	struct fb_deferred_io *fbdefio = info->fbdefio;
0b78f8bcf4951af drivers/video/fbdev/core/fb_defio.c Matthew Wilcox 2021-06-01  318  	struct page *page;
0b78f8bcf4951af drivers/video/fbdev/core/fb_defio.c Matthew Wilcox 2021-06-01  319  	int i;
60b59beafba875a drivers/video/fb_defio.c            Jaya Kumar     2007-05-08  320  
181b74ef794e198 drivers/video/fb_defio.c            Tejun Heo      2011-06-15  321  	cancel_delayed_work_sync(&info->deferred_work);
0b78f8bcf4951af drivers/video/fbdev/core/fb_defio.c Matthew Wilcox 2021-06-01  322  
0b78f8bcf4951af drivers/video/fbdev/core/fb_defio.c Matthew Wilcox 2021-06-01  323  	/* clear out the mapping that we setup */
0b78f8bcf4951af drivers/video/fbdev/core/fb_defio.c Matthew Wilcox 2021-06-01  324  	for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
0b78f8bcf4951af drivers/video/fbdev/core/fb_defio.c Matthew Wilcox 2021-06-01  325  		page = fb_deferred_io_page(info, i);
0b78f8bcf4951af drivers/video/fbdev/core/fb_defio.c Matthew Wilcox 2021-06-01  326  		page->mapping = NULL;
0b78f8bcf4951af drivers/video/fbdev/core/fb_defio.c Matthew Wilcox 2021-06-01  327  	}
3efc61d95259956 drivers/video/fbdev/core/fb_defio.c Takashi Iwai   2023-01-29  328  }
fe94468e5ddd912 drivers/video/fbdev/core/fb_defio.c Takashi Iwai   2023-03-08  329  

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