Use memcpy_to_bvec instead of opencoding the logic.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20210727055646.118787-12-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>