Solution:
You can create a new shortcode for this. You have to paste the code at the current theme > functions.php. You can create a shortcode like this :
add_shortcode( 'user_control', 'user_control_func' );
function user_control_func() {
if ( is_user_logged_in() ) {
wp_redirect('/')
}
}
And you will add shortcode the login form page like this:
[user_control]