Leetcode - Insertion Sort List

 It is quite a basic problem.  However I spent half an hour solving it and made two mistakes. Guess it's because I haven't written some fundamental data structures like linked list for a while and kind of get lost. I should practice these questions more. 

public class Solution {
  public ListNode insertionSortList(ListNode head) {

    if (head == null || head.next == null)
      return head;

    ListNode cNode = head.next;
    ListNode prevcNode = head;

    while (cNode != null) {
      if (cNode.val <= head.val) {
        prevcNode.next = cNode.next;
        cNode.next = head;
        head = cNode;

        cNode = prevcNode.next;
      }

      else {

        ListNode tNode = head;
        while( tNode.next != cNode &&tNode.next.val < cNode.val)
        {
          tNode = tNode.next;
        }

        if(tNode.next == cNode)
        {
          prevcNode = cNode;
          cNode = cNode.next;
        }

        else
        {
          prevcNode.next = cNode.next;
          cNode.next = tNode.next;
          tNode.next = cNode;

          cNode = prevcNode.next;
        }
      }
    }

    return head;
  }
}