[PATCH] hlist_add_after() fix

From: "Pedro Emanuel M. D. Pinto" <pepinto@student.dei.uc.pt>

This currently-unused function is incorrectly implemented.  Fix.

include/linux/list.h

@@ -611,8 +611,11 @@ static inline void hlist_add_after(struct hlist_node *n,
 					struct hlist_node *next)
 {
 	next->next = n->next;
-	*(next->pprev)	= n;
 	n->next = next;
+	next->pprev = &n->next;
+
+	if(next->next)
+		next->next->pprev  = &next->next;
 }
 
 #define hlist_entry(ptr, type, member) container_of(ptr,type,member)