net_sched: fix a memory leak in atm_tc_init()

When tcf_block_get() fails inside atm_tc_init(),
atm_tc_put() is called to release the qdisc p->link.q.
But the flow->ref prevents it to do so, as the flow->ref
is still zero.

Fix this by moving the p->link.ref initialization before
tcf_block_get().

Fixes: 6529eab ("net: sched: introduce tcf block infractructure")
Reported-and-tested-by: [email protected]
Cc: Jamal Hadi Salim <[email protected]>
Cc: Jiri Pirko <[email protected]>
Signed-off-by: Cong Wang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: congwang

net/sched/sch_atm.c

@@ -553,16 +553,16 @@ static int atm_tc_init(struct Qdisc *sch, struct nlattr *opt,
 	if (!p->link.q)
 		p->link.q = &noop_qdisc;
 	pr_debug("atm_tc_init: link (%p) qdisc %p\n", &p->link, p->link.q);
+	p->link.vcc = NULL;
+	p->link.sock = NULL;
+	p->link.common.classid = sch->handle;
+	p->link.ref = 1;
 
 	err = tcf_block_get(&p->link.block, &p->link.filter_list, sch,
 			    extack);
 	if (err)
 		return err;
 
-	p->link.vcc = NULL;
-	p->link.sock = NULL;
-	p->link.common.classid = sch->handle;
-	p->link.ref = 1;
 	tasklet_init(&p->task, sch_atm_dequeue, (unsigned long)sch);
 	return 0;
 }