[paragon-software-group-ntfs3:master 16/16] fs/ntfs3/inode.c:1021:6: warning: variable 'folio' is used uninitialized whenever 'if' condition is true

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

tree:   https://github.com/Paragon-Software-Group/linux-ntfs3.git master
head:   099ef9ab9203dff327f2d61e44773f9acbc01f13
commit: 099ef9ab9203dff327f2d61e44773f9acbc01f13 [16/16] fs/ntfs3: implement iomap-based file operations
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20260101/202601010644.FIhOXy6Y-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260101/202601010644.FIhOXy6Y-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/202601010644.FIhOXy6Y-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> fs/ntfs3/inode.c:1021:6: warning: variable 'folio' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
    1021 |         if (is_resident(ni)) {
         |             ^~~~~~~~~~~~~~~
   fs/ntfs3/inode.c:1024:48: note: uninitialized use occurs here
    1024 |                 while ((folio = writeback_iter(mapping, wbc, folio, &err)))
         |                                                              ^~~~~
   fs/ntfs3/inode.c:1021:2: note: remove the 'if' if its condition is always false
    1021 |         if (is_resident(ni)) {
         |         ^~~~~~~~~~~~~~~~~~~~~~
    1022 |                 struct folio *folio;
         |                 ~~~~~~~~~~~~~~~~~~~~
    1023 | 
    1024 |                 while ((folio = writeback_iter(mapping, wbc, folio, &err)))
         |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    1025 |                         err = ntfs_resident_writepage(folio, wbc);
         |                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    1026 | 
    1027 |                 return err;
         |                 ~~~~~~~~~~~
    1028 |         }
         |         ~
   fs/ntfs3/inode.c:1022:22: note: initialize the variable 'folio' to silence this warning
    1022 |                 struct folio *folio;
         |                                    ^
         |                                     = NULL
   1 warning generated.


vim +1021 fs/ntfs3/inode.c

  1001	
  1002	static int ntfs_writepages(struct address_space *mapping,
  1003				   struct writeback_control *wbc)
  1004	{
  1005		int err;
  1006		struct inode *inode = mapping->host;
  1007		struct ntfs_inode *ni = ntfs_i(inode);
  1008		struct iomap_writepage_ctx wpc = {
  1009			.inode = mapping->host,
  1010			.wbc = wbc,
  1011			.ops = &ntfs_writeback_ops,
  1012		};
  1013	
  1014		/* Avoid any operation if inode is bad. */
  1015		if (unlikely(is_bad_ni(ni)))
  1016			return -EINVAL;
  1017	
  1018		if (unlikely(ntfs3_forced_shutdown(inode->i_sb)))
  1019			return -EIO;
  1020	
> 1021		if (is_resident(ni)) {
  1022			struct folio *folio;
  1023	
  1024			while ((folio = writeback_iter(mapping, wbc, folio, &err)))
  1025				err = ntfs_resident_writepage(folio, wbc);
  1026	
  1027			return err;
  1028		}
  1029	
  1030		return iomap_writepages(&wpc);
  1031	}
  1032	

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