[NETNS][FRAGS]: Make the LRU list per namespace.

The inet_frags.lru_list is used for evicting only, so we have
to make it per-namespace, to evict only those fragments, who's
namespace exceeded its high threshold, but not the whole hash.
Besides, this helps to avoid long loops  in evictor.

The spinlock is not per-namespace because it protects the
hash table as well, which is global.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 00646ed..29b4b09 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -441,7 +441,7 @@
 		return ip_frag_reasm(qp, prev, dev);
 
 	write_lock(&ip4_frags.lock);
-	list_move_tail(&qp->q.lru_list, &ip4_frags.lru_list);
+	list_move_tail(&qp->q.lru_list, &qp->q.net->lru_list);
 	write_unlock(&ip4_frags.lock);
 	return -EINPROGRESS;