DRBD_MAX_BIO_SIZE_SAFE
device->peer_max_bio_size = DRBD_MAX_BIO_SIZE_SAFE;
device->local_max_bio_size = DRBD_MAX_BIO_SIZE_SAFE;
.max_hw_sectors = DRBD_MAX_BIO_SIZE_SAFE >> 8,
peer = max(peer, DRBD_MAX_BIO_SIZE_SAFE);