1 files changed, 24 insertions, 43 deletions

diff --git a/net/sched/sch_prio.c b/net/sched/sch_prio.c
index f4d443aeae54..8f575899adfa 100644
--- a/net/sched/sch_prio.c
+++ b/net/sched/sch_prio.c
@@ -153,8 +153,9 @@ prio_destroy(struct Qdisc *sch)
 static int prio_tune(struct Qdisc *sch, struct nlattr *opt)
 {
         struct prio_sched_data *q = qdisc_priv(sch);
+        struct Qdisc *queues[TCQ_PRIO_BANDS];
+        int oldbands = q->bands, i;
         struct tc_prio_qopt *qopt;
-        int i;
 
         if (nla_len(opt) < sizeof(*qopt))
                 return -EINVAL;
@@ -168,62 +169,42 @@ static int prio_tune(struct Qdisc *sch, struct nlattr *opt)
                         return -EINVAL;
         }
 
+        /* Before commit, make sure we can allocate all new qdiscs */
+        for (i = oldbands; i < qopt->bands; i++) {
+                queues[i] = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
+                                              TC_H_MAKE(sch->handle, i + 1));
+                if (!queues[i]) {
+                        while (i > oldbands)
+                                qdisc_destroy(queues[--i]);
+                        return -ENOMEM;
+                }
+        }
+
         sch_tree_lock(sch);
         q->bands = qopt->bands;
         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
 
-        for (i = q->bands; i < TCQ_PRIO_BANDS; i++) {
+        for (i = q->bands; i < oldbands; i++) {
                 struct Qdisc *child = q->queues[i];
-                q->queues[i] = &noop_qdisc;
-                if (child != &noop_qdisc) {
-                        qdisc_tree_reduce_backlog(child, child->q.qlen, child->qstats.backlog);
-                        qdisc_destroy(child);
-                }
-        }
-        sch_tree_unlock(sch);
 
-        for (i = 0; i < q->bands; i++) {
-                if (q->queues[i] == &noop_qdisc) {
-                        struct Qdisc *child, *old;
-
-                        child = qdisc_create_dflt(sch->dev_queue,
-                                                  &pfifo_qdisc_ops,
-                                                  TC_H_MAKE(sch->handle, i + 1));
-                        if (child) {
-                                sch_tree_lock(sch);
-                                old = q->queues[i];
-                                q->queues[i] = child;
-
-                                if (old != &noop_qdisc) {
-                                        qdisc_tree_reduce_backlog(old,
-                                                                  old->q.qlen,
-                                                                  old->qstats.backlog);
-                                        qdisc_destroy(old);
-                                }
-                                sch_tree_unlock(sch);
-                        }
-                }
+                qdisc_tree_reduce_backlog(child, child->q.qlen,
+                                          child->qstats.backlog);
+                qdisc_destroy(child);
         }
+
+        for (i = oldbands; i < q->bands; i++)
+                q->queues[i] = queues[i];
+
+        sch_tree_unlock(sch);
         return 0;
 }
 
 static int prio_init(struct Qdisc *sch, struct nlattr *opt)
 {
-        struct prio_sched_data *q = qdisc_priv(sch);
-        int i;
-
-        for (i = 0; i < TCQ_PRIO_BANDS; i++)
-                q->queues[i] = &noop_qdisc;
-
-        if (opt == NULL) {
+        if (!opt)
                 return -EINVAL;
-        } else {
-                int err;
 
-                if ((err = prio_tune(sch, opt)) != 0)
-                        return err;
-        }
-        return 0;
+        return prio_tune(sch, opt);
 }
 
 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)