Re: [PATCH v9 5/9] block: Make bio_iov_iter_get_pages() respect bio_required_sector_alignment()

[kernel test robot]

Hi Satya,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on block/for-next]
[also build test ERROR on ext4/dev f2fs/dev-test linus/master v5.13-rc4 next-20210604]
[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]

url:    https://github.com/0day-ci/linux/commits/Satya-Tangirala/add-support-for-direct-I-O-with-fscrypt-using-blk-crypto/20210605-051023
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
config: um-x86_64_defconfig (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/eea1225f680da16dce01bfb2914b9e8b78de298d
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Satya-Tangirala/add-support-for-direct-I-O-with-fscrypt-using-blk-crypto/20210605-051023
        git checkout eea1225f680da16dce01bfb2914b9e8b78de298d
        # save the attached .config to linux build tree
        make W=1 ARCH=um SUBARCH=x86_64

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

   In file included from include/linux/kernel.h:14,
                    from include/asm-generic/bug.h:20,
                    from ./arch/um/include/generated/asm/bug.h:1,
                    from include/linux/bug.h:5,
                    from include/linux/mmdebug.h:5,
                    from include/linux/mm.h:9,
                    from block/bio.c:5:
   block/bio.c: In function 'bio_iov_iter_get_pages':
>> block/bio.c:1131:10: error: implicit declaration of function 'bio_required_sector_alignment' [-Werror=implicit-function-declaration]
    1131 |          bio_required_sector_alignment(bio));
         |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/math.h:14:46: note: in definition of macro '__round_mask'
      14 | #define __round_mask(x, y) ((__typeof__(x))((y)-1))
         |                                              ^
   block/bio.c:1130:20: note: in expansion of macro 'round_down'
    1130 |  aligned_sectors = round_down(bio_sectors(bio),
         |                    ^~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/bio_required_sector_alignment +1131 block/bio.c

  1083	
  1084	/**
  1085	 * bio_iov_iter_get_pages - add user or kernel pages to a bio
  1086	 * @bio: bio to add pages to
  1087	 * @iter: iov iterator describing the region to be added
  1088	 *
  1089	 * This takes either an iterator pointing to user memory, or one pointing to
  1090	 * kernel pages (BVEC iterator). If we're adding user pages, we pin them and
  1091	 * map them into the kernel. On IO completion, the caller should put those
  1092	 * pages. For bvec based iterators bio_iov_iter_get_pages() uses the provided
  1093	 * bvecs rather than copying them. Hence anyone issuing kiocb based IO needs
  1094	 * to ensure the bvecs and pages stay referenced until the submitted I/O is
  1095	 * completed by a call to ->ki_complete() or returns with an error other than
  1096	 * -EIOCBQUEUED. The caller needs to check if the bio is flagged BIO_NO_PAGE_REF
  1097	 * on IO completion. If it isn't, then pages should be released.
  1098	 *
  1099	 * The function tries, but does not guarantee, to pin as many pages as
  1100	 * fit into the bio, or are requested in @iter, whatever is smaller. If
  1101	 * MM encounters an error pinning the requested pages, it stops. Error
  1102	 * is returned only if 0 pages could be pinned. It also ensures that the number
  1103	 * of sectors added to the bio is aligned to bio_required_sector_alignment().
  1104	 *
  1105	 * It's intended for direct IO, so doesn't do PSI tracking, the caller is
  1106	 * responsible for setting BIO_WORKINGSET if necessary.
  1107	 */
  1108	int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
  1109	{
  1110		int ret = 0;
  1111		unsigned int aligned_sectors;
  1112	
  1113		if (iov_iter_is_bvec(iter)) {
  1114			if (bio_op(bio) == REQ_OP_ZONE_APPEND)
  1115				return bio_iov_bvec_set_append(bio, iter);
  1116			return bio_iov_bvec_set(bio, iter);
  1117		}
  1118	
  1119		do {
  1120			if (bio_op(bio) == REQ_OP_ZONE_APPEND)
  1121				ret = __bio_iov_append_get_pages(bio, iter);
  1122			else
  1123				ret = __bio_iov_iter_get_pages(bio, iter);
  1124		} while (!ret && iov_iter_count(iter) && !bio_full(bio, 0));
  1125	
  1126		/*
  1127		 * Ensure that number of sectors in bio is aligned to
  1128		 * bio_required_sector_align()
  1129		 */
  1130		aligned_sectors = round_down(bio_sectors(bio),
> 1131					     bio_required_sector_alignment(bio));
  1132		iov_iter_revert(iter, (bio_sectors(bio) - aligned_sectors) << SECTOR_SHIFT);
  1133		bio_truncate(bio, aligned_sectors << SECTOR_SHIFT);
  1134	
  1135		/* don't account direct I/O as memory stall */
  1136		bio_clear_flag(bio, BIO_WORKINGSET);
  1137		return bio->bi_vcnt ? 0 : ret;
  1138	}
  1139	EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages);
  1140	

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0-DAY CI Kernel Test Service, Intel Corporation
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