BLOCKIF_IOV_MAX
struct iovec br_iov[BLOCKIF_IOV_MAX];
for (i = 0, j = 0; i < prdtl && j < BLOCKIF_IOV_MAX && left > 0;
if (j == BLOCKIF_IOV_MAX) {
( NVME_MAX_IOVEC > BLOCKIF_IOV_MAX ? \
NVME_MAX_IOVEC - BLOCKIF_IOV_MAX : \
struct iovec iov[BLOCKIF_IOV_MAX + 2];
n = vq_getchain(vq, iov, BLOCKIF_IOV_MAX + 2, &req);
assert(n >= 2 && n <= BLOCKIF_IOV_MAX + 2);
sc->vbsc_cfg.vbc_seg_max = MIN(VTBLK_RINGSZ - 2, BLOCKIF_IOV_MAX);