inet: frags: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Stefan Schmidt <stefan@osg.samsung.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: Florian Westphal <fw@strlen.de>
Cc: linux-wpan@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: netfilter-devel@vger.kernel.org
Cc: coreteam@netfilter.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Stefan Schmidt <stefan@osg.samsung.com> # for ieee802154
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 46408c2..9215654 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -190,12 +190,13 @@ static bool frag_expire_skip_icmp(u32 user)
 /*
  * Oops, a fragment queue timed out.  Kill it and send an ICMP reply.
  */
-static void ip_expire(unsigned long arg)
+static void ip_expire(struct timer_list *t)
 {
+	struct inet_frag_queue *frag = from_timer(frag, t, timer);
 	struct ipq *qp;
 	struct net *net;
 
-	qp = container_of((struct inet_frag_queue *) arg, struct ipq, q);
+	qp = container_of(frag, struct ipq, q);
 	net = container_of(qp->q.net, struct net, ipv4.frags);
 
 	rcu_read_lock();