pkt_sched: fq: qdisc dismantle fixes

fq_reset() should drops all packets in queue, including
throttled flows.

This patch moves code from fq_destroy() to fq_reset()
to do the cleaning.

fq_change() must stop calling fq_dequeue() if all remaining
packets are from throttled flows.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index 32ad015..fc6de56 100644 (file)
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -285,7 +285,7 @@ static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q)
 
 
 /* remove one skb from head of flow queue */
-static struct sk_buff *fq_dequeue_head(struct fq_flow *flow)
+static struct sk_buff *fq_dequeue_head(struct Qdisc *sch, struct fq_flow *flow)
 {
        struct sk_buff *skb = flow->head;
 
@@ -293,6 +293,8 @@ static struct sk_buff *fq_dequeue_head(struct fq_flow *flow)
                flow->head = skb->next;
                skb->next = NULL;
                flow->qlen--;
+               sch->qstats.backlog -= qdisc_pkt_len(skb);
+               sch->q.qlen--;
        }
        return skb;
 }
@@ -419,7 +421,7 @@ static struct sk_buff *fq_dequeue(struct Qdisc *sch)
        struct sk_buff *skb;
        struct fq_flow *f;
 
-       skb = fq_dequeue_head(&q->internal);
+       skb = fq_dequeue_head(sch, &q->internal);
        if (skb)
                goto out;
        fq_check_throttled(q, now);
@@ -449,7 +451,7 @@ begin:
                goto begin;
        }
 
-       skb = fq_dequeue_head(f);
+       skb = fq_dequeue_head(sch, f);
        if (!skb) {
                head->first = f->next;
                /* force a pass through old_flows to prevent starvation */
@@ -490,19 +492,44 @@ begin:
                }
        }
 out:
-       sch->qstats.backlog -= qdisc_pkt_len(skb);
        qdisc_bstats_update(sch, skb);
-       sch->q.qlen--;
        qdisc_unthrottled(sch);
        return skb;
 }
 
 static void fq_reset(struct Qdisc *sch)
 {
+       struct fq_sched_data *q = qdisc_priv(sch);
+       struct rb_root *root;
        struct sk_buff *skb;
+       struct rb_node *p;
+       struct fq_flow *f;
+       unsigned int idx;
 
-       while ((skb = fq_dequeue(sch)) != NULL)
+       while ((skb = fq_dequeue_head(sch, &q->internal)) != NULL)
                kfree_skb(skb);
+
+       if (!q->fq_root)
+               return;
+
+       for (idx = 0; idx < (1U << q->fq_trees_log); idx++) {
+               root = &q->fq_root[idx];
+               while ((p = rb_first(root)) != NULL) {
+                       f = container_of(p, struct fq_flow, fq_node);
+                       rb_erase(p, root);
+
+                       while ((skb = fq_dequeue_head(sch, f)) != NULL)
+                               kfree_skb(skb);
+
+                       kmem_cache_free(fq_flow_cachep, f);
+               }
+       }
+       q->new_flows.first      = NULL;
+       q->old_flows.first      = NULL;
+       q->delayed              = RB_ROOT;
+       q->flows                = 0;
+       q->inactive_flows       = 0;
+       q->throttled_flows      = 0;
 }
 
 static void fq_rehash(struct fq_sched_data *q,
@@ -645,6 +672,8 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt)
        while (sch->q.qlen > sch->limit) {
                struct sk_buff *skb = fq_dequeue(sch);
 
+               if (!skb)
+                       break;
                kfree_skb(skb);
                drop_count++;
        }
@@ -657,21 +686,9 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt)
 static void fq_destroy(struct Qdisc *sch)
 {
        struct fq_sched_data *q = qdisc_priv(sch);
-       struct rb_root *root;
-       struct rb_node *p;
-       unsigned int idx;
 
-       if (q->fq_root) {
-               for (idx = 0; idx < (1U << q->fq_trees_log); idx++) {
-                       root = &q->fq_root[idx];
-                       while ((p = rb_first(root)) != NULL) {
-                               rb_erase(p, root);
-                               kmem_cache_free(fq_flow_cachep,
-                                               container_of(p, struct fq_flow, fq_node));
-                       }
-               }
-               kfree(q->fq_root);
-       }
+       fq_reset(sch);
+       kfree(q->fq_root);
        qdisc_watchdog_cancel(&q->watchdog);
 }