Reverse a linked list

This algorithm is a little more efficient than the last I posted about sorting a linked list, running in O(N) time. The algorithm requires a doubly linked list.

queue_length = queue_size(q);

front = q->head;
back = q->tail;

for (i = 0; i < queue_length / 2; i++) {
 
 temp = front->e;
 front->e = back->e;
 back->e = temp;
 
 front = front->next;
 back = back->prev;
}