Commit 7a07210b authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

block: introduce blk_validate_byte_range() 



In preparation to further changes extract a helper function out of
blk_ioctl_discard() that validates if we can do IO against the given
range of disk byte addresses.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/19a7779323c71e742a2f511e4cf49efcfd68cfd4.1726072086.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a12c883a

block/ioctl.c

+32 −19
Original line number Diff line number Diff line
@@ -92,41 +92,54 @@ static int compat_blkpg_ioctl(struct block_device *bdev, 
}

#endif



/*

 * Check that [start, start + len) is a valid range from the block device's

 * perspective, including verifying that it can be correctly translated into

 * logical block addresses.

 */

static int blk_validate_byte_range(struct block_device *bdev,

				   uint64_t start, uint64_t len)

{

	unsigned int bs_mask = bdev_logical_block_size(bdev) - 1;

	uint64_t end;



	if ((start | len) & bs_mask)

		return -EINVAL;

	if (!len)

		return -EINVAL;

	if (check_add_overflow(start, len, &end) || end > bdev_nr_bytes(bdev))

		return -EINVAL;



	return 0;

}



static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode,

		unsigned long arg)

{

	unsigned int bs_mask = bdev_logical_block_size(bdev) - 1;

	uint64_t range[2], start, len, end;

	uint64_t range[2], start, len;

	struct bio *prev = NULL, *bio;

	sector_t sector, nr_sects;

	struct blk_plug plug;

	int err;



	if (!(mode & BLK_OPEN_WRITE))

		return -EBADF;



	if (!bdev_max_discard_sectors(bdev))

		return -EOPNOTSUPP;

	if (bdev_read_only(bdev))

		return -EPERM;



	if (copy_from_user(range, (void __user *)arg, sizeof(range)))

		return -EFAULT;



	start = range[0];

	len = range[1];



	if (!len)

		return -EINVAL;

	if ((start | len) & bs_mask)

		return -EINVAL;

	if (!bdev_max_discard_sectors(bdev))

		return -EOPNOTSUPP;



	if (check_add_overflow(start, len, &end) ||

	    end > bdev_nr_bytes(bdev))

		return -EINVAL;

	if (!(mode & BLK_OPEN_WRITE))

		return -EBADF;

	if (bdev_read_only(bdev))

		return -EPERM;

	err = blk_validate_byte_range(bdev, start, len);

	if (err)

		return err;



	filemap_invalidate_lock(bdev->bd_mapping);

	err = truncate_bdev_range(bdev, mode, start, end - 1);

	err = truncate_bdev_range(bdev, mode, start, start + len - 1);

	if (err)

		goto fail;