[chao:bugfix/common 10/10] fs/f2fs/compress.c:1245:40: warning: suggest parentheses around '-' inside '<<'

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

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/chao/linux.git bugfix/common
head:   4aa8c9b233e491f55b9608d4212b5eb7c6f3338a
commit: 4aa8c9b233e491f55b9608d4212b5eb7c6f3338a [10/10] f2fs: clean up f2fs_truncate_partial_cluster()
config: arc-randconfig-001-20250801 (https://download.01.org/0day-ci/archive/20250801/202508011723.hopSkVCa-lkp@intel.com/config)
compiler: arc-linux-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250801/202508011723.hopSkVCa-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/202508011723.hopSkVCa-lkp@intel.com/

All warnings (new ones prefixed by >>):

   fs/f2fs/compress.c: In function 'f2fs_truncate_partial_cluster':
>> fs/f2fs/compress.c:1245:40: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
    1245 |         for (i = 1 << log_cluster_size - 1; i >= 0; i--) {
         |                       ~~~~~~~~~~~~~~~~~^~~


vim +1245 fs/f2fs/compress.c

  1213	
  1214	int f2fs_truncate_partial_cluster(struct inode *inode, u64 from, bool lock)
  1215	{
  1216		void *fsdata = NULL;
  1217		struct page *pagep;
  1218		struct page **rpages;
  1219		int log_cluster_size = F2FS_I(inode)->i_log_cluster_size;
  1220		pgoff_t start_idx = from >> (PAGE_SHIFT + log_cluster_size) <<
  1221								log_cluster_size;
  1222		int i;
  1223		int err;
  1224	
  1225		err = f2fs_is_compressed_cluster(inode, start_idx);
  1226		if (err < 0)
  1227			return err;
  1228	
  1229		/* truncate normal cluster */
  1230		if (!err)
  1231			return f2fs_do_truncate_blocks(inode, from, lock);
  1232	
  1233		/* truncate compressed cluster */
  1234		err = f2fs_prepare_compress_overwrite(inode, &pagep,
  1235							start_idx, &fsdata);
  1236	
  1237		/* should not be a normal cluster */
  1238		f2fs_bug_on(F2FS_I_SB(inode), err == 0);
  1239	
  1240		if (err <= 0)
  1241			return err;
  1242	
  1243		rpages = fsdata;
  1244	
> 1245		for (i = 1 << log_cluster_size - 1; i >= 0; i--) {
  1246			struct folio *folio = page_folio(rpages[i]);
  1247			loff_t start = (loff_t)folio->index << PAGE_SHIFT;
  1248	
  1249			if (from > start) {
  1250				folio_zero_segment(folio, from - start,
  1251						folio_size(folio));
  1252				break;
  1253			}
  1254			folio_zero_segment(folio, 0, folio_size(folio));
  1255		}
  1256	
  1257		f2fs_compress_write_end(inode, fsdata, start_idx, true);
  1258		return 0;
  1259	}
  1260	

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