net_sched: always clone skbs

Pawel reported a panic related to handling shared skbs in ixgbe
incorrectly. So we need to revert my previous patch to work around
this bug. Instead of reverting the patch completely, I just revert
the essential lines, so we can add the previous optimization
back more easily in future.

    commit 3511c9132f8b1e1b5634e41a3331c44b0c13be70
    Author: Changli Gao <xiaosuo@gmail.com>
    Date:   Sat Oct 16 13:04:08 2010 +0000

        net_sched: remove the unused parameter of qdisc_create_dflt()

Reported-by: Pawel Staszewski <pstaszewski@itcare.pl>
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index ea1f8a8..79f34e2 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -610,11 +610,7 @@
 {
 	struct sk_buff *n;
 
-	if ((action == TC_ACT_STOLEN || action == TC_ACT_QUEUED) &&
-	    !skb_shared(skb))
-		n = skb_get(skb);
-	else
-		n = skb_clone(skb, gfp_mask);
+	n = skb_clone(skb, gfp_mask);
 
 	if (n) {
 		n->tc_verd = SET_TC_VERD(n->tc_verd, 0);