Re: [akpm-mm:mm-unstable 146/165] drivers/video/fbdev/core/fb_defio.c:272:17: error: implicit declaration of function 'mapping_wrprotect_range'

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

On Sat, Feb 08, 2025 at 01:05:41PM +0800, kernel test robot wrote:
> Hi Lorenzo,

Thanks for the report!

>
> FYI, the error/warning was bisected to this commit, please ignore it if it's irrelevant.
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
> head:   8bf30f9d23eb5040d37e6e712789cee8e71e1577
> commit: 85d65aec481df149bc5280cf1ad5f9b76f59f153 [146/165] fb_defio: do not use deprecated page->mapping, index fields
> config: sh-allmodconfig (https://download.01.org/0day-ci/archive/20250208/202502081235.v7ook2My-lkp@intel.com/config)
> compiler: sh4-linux-gcc (GCC) 14.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250208/202502081235.v7ook2My-lkp@intel.com/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202502081235.v7ook2My-lkp@intel.com/
>
> All errors (new ones prefixed by >>):
>
>    drivers/video/fbdev/core/fb_defio.c: In function 'fb_deferred_io_fault':
>    drivers/video/fbdev/core/fb_defio.c:136:48: error: macro "fb_err" requires 3 arguments, but only 1 given
>      136 |                 fb_err("no mapping available\n");
>          |                                                ^
>    In file included from drivers/video/fbdev/core/fb_defio.c:19:
>    include/linux/fb.h:887:9: note: macro "fb_err" defined here
>      887 | #define fb_err(fb_info, fmt, ...)                                       \
>          |         ^~~~~~
>    drivers/video/fbdev/core/fb_defio.c:136:17: error: 'fb_err' undeclared (first use in this function); did you mean 'xa_err'?
>      136 |                 fb_err("no mapping available\n");

My bad, I will fix this up.

>          |                 ^~~~~~
>          |                 xa_err
>    drivers/video/fbdev/core/fb_defio.c:136:17: note: each undeclared identifier is reported only once for each function it appears in
>    drivers/video/fbdev/core/fb_defio.c: In function 'fb_deferred_io_work':
> >> drivers/video/fbdev/core/fb_defio.c:272:17: error: implicit declaration of function 'mapping_wrprotect_range' [-Wimplicit-function-declaration]
>      272 |                 mapping_wrprotect_range(fbdefio->mapping, pgoff,
>          |                 ^~~~~~~~~~~~~~~~~~~~~~~
>
> Kconfig warnings: (for reference only)
>    WARNING: unmet direct dependencies detected for FB_DEFERRED_IO
>    Depends on [n]: HAS_IOMEM [=y] && FB_CORE [=m] && MMU [=n]
>    Selected by [m]:
>    - FB_SH_MOBILE_LCDC [=m] && FB [=m] && HAVE_CLK [=y] && HAS_IOMEM [=y] && (SUPERH [=y] || COMPILE_TEST [=y]) && FB_DEVICE [=y] && BACKLIGHT_CLASS_DEVICE [=m]
>    - FB_SYSMEM_HELPERS_DEFERRED [=y] && HAS_IOMEM [=y] && FB_CORE [=m]

OK I think on reflection I probably have to propagate this requirement to
all instances of "select FB_DEFERRED_IO" configs, I had assumed that
Kconfig would figure this out but I guess not :)

>
>
> vim +/mapping_wrprotect_range +272 drivers/video/fbdev/core/fb_defio.c
>
>    258
>    259	/* workqueue callback */
>    260	static void fb_deferred_io_work(struct work_struct *work)
>    261	{
>    262		struct fb_info *info = container_of(work, struct fb_info, deferred_work.work);
>    263		struct fb_deferred_io_pageref *pageref, *next;
>    264		struct fb_deferred_io *fbdefio = info->fbdefio;
>    265
>    266		/* here we wrprotect the page's mappings, then do all deferred IO. */
>    267		mutex_lock(&fbdefio->lock);
>    268		list_for_each_entry(pageref, &fbdefio->pagereflist, list) {
>    269			struct page *page = pageref->page;
>    270			pgoff_t pgoff = pageref->offset >> PAGE_SHIFT;
>    271
>  > 272			mapping_wrprotect_range(fbdefio->mapping, pgoff,
>    273						page_to_pfn(page), 1);
>    274		}
>    275
>    276		/* driver's callback with pagereflist */
>    277		fbdefio->deferred_io(info, &fbdefio->pagereflist);
>    278
>    279		/* clear the list */
>    280		list_for_each_entry_safe(pageref, next, &fbdefio->pagereflist, list)
>    281			fb_deferred_io_pageref_put(pageref, info);
>    282
>    283		mutex_unlock(&fbdefio->lock);
>    284	}
>    285
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki

I will probably do a respin of the series to make all this easier.