Shortcode for custom query

function category_post_shortcode($atts){
		extract( shortcode_atts( array(
			'title' => '',
			'link' => '',
			'category' => '',
		), $atts, 'category_post' ) );
		
		global $post;

		$q = new WP_Query(
			array( 'category' => $category, 'posts_per_page' => '3', 'post_type' => 'post')
			);
	$list = '<div class="latest_from_category"><h2 class="latest_frm_cat_title">'.$title.'</h2> <a href="'.$link.'" class="latest_more_link">more</a>';

	while($q->have_posts()) : $q->the_post();
		//get the ID of your post in the loop
		$id = get_the_ID();

		$post_excerpt = get_post_meta($id, 'post_excerpt', true);  
		$post_thumbnail= get_the_post_thumbnail( $post->ID, 'post-thumbnail' ); 
		       
		$list .= '
		
							<div class="single_cate_post floatleft">
								'.$post_thumbnail.'
								<h3>'.get_the_title().'</h3> 
								<p>'.$post_excerpt.'</p>
								<a href="'.get_permalink().'" class="readmore">Read More</a>
							</div>		
		';        
	endwhile;
	$list.= '</div>';
	wp_reset_query();
	return $list;
	}
	add_shortcode('category_post', 'category_post_shortcode');