Add canoncial from all pages to the first. Wordpress

function noindex_paged() {
	if ( is_paged() ){   ?>
	
	<link rel="canonical" href="<?php 
	global $wp;
	$current_url = home_url(add_query_arg(array(), $wp->request));
	$s = home_url(add_query_arg(array(), $wp->request));
	echo strstr($s, 'page', true);?>"/>
	<?php 
	}
} 

add_action('wp_head','noindex_paged',2);