cifs: smbd: Check for iov length on sending the last iov

When sending the last iov that breaks into smaller buffers to fit the
transfer size, it's necessary to check if this is the last iov.

If this is the latest iov, stop and proceed to send pages.
Signed-off-by: NLong Li <longli@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>

fs/cifs/smbdirect.c

@@ -2194,6 +2194,8 @@ int smbd_send(struct smbd_connection *info, struct smb_rqst *rqst)
 						goto done;
 				}
 				i++;
+				if (i == rqst->rq_nvec)
+					break;
 			}
 			start = i;
 			buflen = 0;