Commit 73a768d5 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: factor out a blk_write_zeroes_limit helper 



Contrary to the comment in __blkdev_issue_write_zeroes, nothing here
checks for a potential bi_size overflow.  Add a helper mirroring
the secure erase code for the check.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240701165219.1571322-6-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 2f20872e

block/blk-lib.c

+11 −7
Original line number Diff line number Diff line
@@ -103,24 +103,28 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, 
}

EXPORT_SYMBOL(blkdev_issue_discard);



static sector_t bio_write_zeroes_limit(struct block_device *bdev)

{

	sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;



	return min(bdev_write_zeroes_sectors(bdev),

		(UINT_MAX >> SECTOR_SHIFT) & ~bs_mask);

}



static int __blkdev_issue_write_zeroes(struct block_device *bdev,

		sector_t sector, sector_t nr_sects, gfp_t gfp_mask,

		struct bio **biop, unsigned flags)

{

	struct bio *bio = *biop;

	unsigned int max_sectors;



	if (bdev_read_only(bdev))

		return -EPERM;



	/* Ensure that max_sectors doesn't overflow bi_size */

	max_sectors = bdev_write_zeroes_sectors(bdev);



	if (max_sectors == 0)

	if (!bdev_write_zeroes_sectors(bdev))

		return -EOPNOTSUPP;



	while (nr_sects) {

		unsigned int len = min_t(sector_t, nr_sects, max_sectors);

		unsigned int len = min_t(sector_t, nr_sects,

				bio_write_zeroes_limit(bdev));



		bio = blk_next_bio(bio, bdev, 0, REQ_OP_WRITE_ZEROES, gfp_mask);

		bio->bi_iter.bi_sector = sector;