[PATCH 2/7] udp_vu: Assert iov_tail_clone() return before assigning to msg_iovlen

iov_tail_clone() returns ssize_t, but its return value was assigned directly to msg.msg_iovlen which is size_t. Add an assert to document the invariant that the clone into a VIRTQUEUE_MAX_SIZE array cannot fail. Signed-off-by: Jon Maloy --- udp_vu.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/udp_vu.c b/udp_vu.c index e4fb1057..5d6f45ec 100644 --- a/udp_vu.c +++ b/udp_vu.c @@ -67,11 +67,14 @@ static ssize_t udp_vu_sock_recv(struct iov_tail *payload, size_t *cnt, int s) struct iovec msg_iov[VIRTQUEUE_MAX_SIZE]; struct msghdr msg = { 0 }; size_t iov_used; + ssize_t iovlen; ssize_t dlen; + iovlen = iov_tail_clone(msg_iov, ARRAY_SIZE(msg_iov), payload); + assert(iovlen >= 0); + msg.msg_iov = msg_iov; - msg.msg_iovlen = iov_tail_clone(msg.msg_iov, ARRAY_SIZE(msg_iov), - payload); + msg.msg_iovlen = iovlen; /* read data from the socket */ dlen = recvmsg(s, &msg, 0); -- 2.52.0