net/smc: use announced length in sock_recvmsg()

Not every CLC proposal message needs the maximum buffer length.
Due to the MSG_WAITALL flag, it is important to use the peeked
real length when receiving the message.

Fixes: d63d271c ("smc: switch to sock_recvmsg()")
Signed-off-by: NUrsula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/smc/smc_clc.c

@@ -133,7 +133,7 @@ int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
 
 	/* receive the complete CLC message */
 	memset(&msg, 0, sizeof(struct msghdr));
-	iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, &vec, 1, buflen);
+	iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, &vec, 1, datlen);
 	krflags = MSG_WAITALL;
 	smc->clcsock->sk->sk_rcvtimeo = CLC_WAIT_TIME;
 	len = sock_recvmsg(smc->clcsock, &msg, krflags);