Re: [PATCH v2] fs: Make wbc_to_tag() inline and use it in fs.

[kernel test robot <lkp@intel.com>]

Hi Julian,

kernel test robot noticed the following build errors:

[auto build test ERROR on kdave/for-next]
[also build test ERROR on ceph-client/testing ceph-client/for-linus tytso-ext4/dev jaegeuk-f2fs/dev-test jaegeuk-f2fs/dev gfs2/for-next akpm-mm/mm-everything linus/master v6.17 next-20250929]
[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/Julian-Sun/fs-Make-wbc_to_tag-inline-and-use-it-in-fs/20250929-191847
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git for-next
patch link:    https://lore.kernel.org/r/20250929111349.448324-1-sunjunchao%40bytedance.com
patch subject: [PATCH v2] fs: Make wbc_to_tag() inline and use it in fs.
config: arc-randconfig-001-20250930 (https://download.01.org/0day-ci/archive/20250930/202509300940.yjAtss49-lkp@intel.com/config)
compiler: arc-linux-gcc (GCC) 9.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250930/202509300940.yjAtss49-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/202509300940.yjAtss49-lkp@intel.com/

All errors (new ones prefixed by >>):

   mm/page-writeback.c: In function 'writeback_get_folio':
>> mm/page-writeback.c:2456:5: error: implicit declaration of function 'wbc_to_tag' [-Werror=implicit-function-declaration]
    2456 |     wbc_to_tag(wbc), &wbc->fbatch);
         |     ^~~~~~~~~~
   cc1: some warnings being treated as errors
--
   fs/f2fs/data.c: In function 'f2fs_write_cache_pages':
>> fs/f2fs/data.c:3006:8: error: implicit declaration of function 'wbc_to_tag' [-Werror=implicit-function-declaration]
    3006 |  tag = wbc_to_tag(wbc);
         |        ^~~~~~~~~~
   cc1: some warnings being treated as errors
--
   fs/btrfs/extent_io.c: In function 'extent_write_cache_pages':
>> fs/btrfs/extent_io.c:2463:8: error: implicit declaration of function 'wbc_to_tag' [-Werror=implicit-function-declaration]
    2463 |  tag = wbc_to_tag(wbc);
         |        ^~~~~~~~~~
   cc1: some warnings being treated as errors
--
   fs/ext4/inode.c: In function 'mpage_prepare_extent_to_map':
>> fs/ext4/inode.c:2622:8: error: implicit declaration of function 'wbc_to_tag' [-Werror=implicit-function-declaration]
    2622 |  tag = wbc_to_tag(mpd->wbc);
         |        ^~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/wbc_to_tag +2456 mm/page-writeback.c

751e0d559c62a8 Matthew Wilcox (Oracle  2024-02-15  2444) 
e6d0ab87c8efe9 Matthew Wilcox (Oracle  2024-02-15  2445) static struct folio *writeback_get_folio(struct address_space *mapping,
751e0d559c62a8 Matthew Wilcox (Oracle  2024-02-15  2446) 		struct writeback_control *wbc)
751e0d559c62a8 Matthew Wilcox (Oracle  2024-02-15  2447) {
e6d0ab87c8efe9 Matthew Wilcox (Oracle  2024-02-15  2448) 	struct folio *folio;
e6d0ab87c8efe9 Matthew Wilcox (Oracle  2024-02-15  2449) 
a2cbc13638d909 Matthew Wilcox (Oracle  2024-02-15  2450) retry:
e6d0ab87c8efe9 Matthew Wilcox (Oracle  2024-02-15  2451) 	folio = folio_batch_next(&wbc->fbatch);
e6d0ab87c8efe9 Matthew Wilcox (Oracle  2024-02-15  2452) 	if (!folio) {
751e0d559c62a8 Matthew Wilcox (Oracle  2024-02-15  2453) 		folio_batch_release(&wbc->fbatch);
751e0d559c62a8 Matthew Wilcox (Oracle  2024-02-15  2454) 		cond_resched();
751e0d559c62a8 Matthew Wilcox (Oracle  2024-02-15  2455) 		filemap_get_folios_tag(mapping, &wbc->index, wbc_end(wbc),
751e0d559c62a8 Matthew Wilcox (Oracle  2024-02-15 @2456) 				wbc_to_tag(wbc), &wbc->fbatch);
e6d0ab87c8efe9 Matthew Wilcox (Oracle  2024-02-15  2457) 		folio = folio_batch_next(&wbc->fbatch);
a2cbc13638d909 Matthew Wilcox (Oracle  2024-02-15  2458) 		if (!folio)
a2cbc13638d909 Matthew Wilcox (Oracle  2024-02-15  2459) 			return NULL;
e6d0ab87c8efe9 Matthew Wilcox (Oracle  2024-02-15  2460) 	}
e6d0ab87c8efe9 Matthew Wilcox (Oracle  2024-02-15  2461) 
a2cbc13638d909 Matthew Wilcox (Oracle  2024-02-15  2462) 	folio_lock(folio);
a2cbc13638d909 Matthew Wilcox (Oracle  2024-02-15  2463) 	if (unlikely(!folio_prepare_writeback(mapping, wbc, folio))) {
a2cbc13638d909 Matthew Wilcox (Oracle  2024-02-15  2464) 		folio_unlock(folio);
a2cbc13638d909 Matthew Wilcox (Oracle  2024-02-15  2465) 		goto retry;
a2cbc13638d909 Matthew Wilcox (Oracle  2024-02-15  2466) 	}
a2cbc13638d909 Matthew Wilcox (Oracle  2024-02-15  2467) 
a2cbc13638d909 Matthew Wilcox (Oracle  2024-02-15  2468) 	trace_wbc_writepage(wbc, inode_to_bdi(mapping->host));
e6d0ab87c8efe9 Matthew Wilcox (Oracle  2024-02-15  2469) 	return folio;
751e0d559c62a8 Matthew Wilcox (Oracle  2024-02-15  2470) }
751e0d559c62a8 Matthew Wilcox (Oracle  2024-02-15  2471) 

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