ceph: messenger: check return from get_authorizer

In prepare_connect_authorizer(), a connection's get_authorizer
method is called but ignores its return value.  This function can
return an error, so check for it and return it if that ever occurs.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

net/ceph/messenger.c

@@ -658,6 +658,7 @@ static int prepare_connect_authorizer(struct ceph_connection *con)
  void *auth_buf;
  int auth_len;
  int auth_protocol;
+ int ret;
 
  if (!con->ops->get_authorizer) {
  con->out_connect.authorizer_protocol = CEPH_AUTH_UNKNOWN;
@@ -673,11 +674,14 @@ static int prepare_connect_authorizer(struct ceph_connection *con)
  auth_buf = NULL;
  auth_len = 0;
  auth_protocol = CEPH_AUTH_UNKNOWN;
- con->ops->get_authorizer(con, &auth_buf, &auth_len, &auth_protocol,
- &con->auth_reply_buf, &con->auth_reply_buf_len,
- con->auth_retry);
+ ret = con->ops->get_authorizer(con, &auth_buf, &auth_len,
+ &auth_protocol, &con->auth_reply_buf,
+ &con->auth_reply_buf_len, con->auth_retry);
  mutex_lock(&con->mutex);
 
+ if (ret)
+ return ret;
+
  if (test_bit(CLOSED, &con->state) || test_bit(OPENING, &con->state))
  return -EAGAIN;