NV_FRAGMENT_SIZE
req = kzalloc_flex(*req, fragment, NV_FRAGMENT_SIZE);
req->frag_size = NV_FRAGMENT_SIZE;
req->hdr.len = struct_size(req, fragment, NV_FRAGMENT_SIZE);
if (left <= NV_FRAGMENT_SIZE) {
data += NV_FRAGMENT_SIZE;
left -= NV_FRAGMENT_SIZE;