Re: [RFC v2 2/2] block: use mm_huge_zero_folio in __blkdev_issue_zero_pages()

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

Hi Pankaj,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build warnings:

[auto build test WARNING on f1f6aceb82a55f87d04e2896ac3782162e7859bd]

url:    https://github.com/intel-lab-lkp/linux/commits/Pankaj-Raghav/mm-add-THP_HUGE_ZERO_PAGE_ALWAYS-config-option/20250522-170442
base:   f1f6aceb82a55f87d04e2896ac3782162e7859bd
patch link:    https://lore.kernel.org/r/20250522090243.758943-3-p.raghav%40samsung.com
patch subject: [RFC v2 2/2] block: use mm_huge_zero_folio in __blkdev_issue_zero_pages()
config: arm-randconfig-003-20250523 (https://download.01.org/0day-ci/archive/20250523/202505231416.GECtFkXP-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 7.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250523/202505231416.GECtFkXP-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/202505231416.GECtFkXP-lkp@intel.com/

All warnings (new ones prefixed by >>):

   block/blk-lib.c: In function '__blkdev_issue_zero_pages':
   block/blk-lib.c:201:15: error: implicit declaration of function 'mm_get_huge_zero_folio'; did you mean 'mm_put_huge_zero_folio'? [-Werror=implicit-function-declaration]
     zero_folio = mm_get_huge_zero_folio(NULL);
                  ^~~~~~~~~~~~~~~~~~~~~~
                  mm_put_huge_zero_folio
>> block/blk-lib.c:201:13: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
     zero_folio = mm_get_huge_zero_folio(NULL);
                ^
   cc1: some warnings being treated as errors


vim +201 block/blk-lib.c

   194	
   195	static void __blkdev_issue_zero_pages(struct block_device *bdev,
   196			sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
   197			struct bio **biop, unsigned int flags)
   198	{
   199		struct folio *zero_folio;
   200	
 > 201		zero_folio = mm_get_huge_zero_folio(NULL);
   202		if (!zero_folio)
   203			zero_folio = page_folio(ZERO_PAGE(0));
   204	
   205		while (nr_sects) {
   206			unsigned int nr_vecs = __blkdev_sectors_to_bio_pages(nr_sects);
   207			struct bio *bio;
   208	
   209			bio = bio_alloc(bdev, nr_vecs, REQ_OP_WRITE, gfp_mask);
   210			bio->bi_iter.bi_sector = sector;
   211	
   212			if ((flags & BLKDEV_ZERO_KILLABLE) &&
   213			    fatal_signal_pending(current))
   214				break;
   215	
   216			do {
   217				unsigned int len, added = 0;
   218	
   219				len = min_t(sector_t, folio_size(zero_folio),
   220					    nr_sects << SECTOR_SHIFT);
   221				if (bio_add_folio(bio, zero_folio, len, 0))
   222					added = len;
   223				if (added < len)
   224					break;
   225				nr_sects -= added >> SECTOR_SHIFT;
   226				sector += added >> SECTOR_SHIFT;
   227			} while (nr_sects);
   228	
   229			*biop = bio_chain_and_submit(*biop, bio);
   230			cond_resched();
   231		}
   232	}
   233	

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