1 files changed, 69 insertions, 26 deletions

diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c
index 9af01f3df18c..e4723d31fdd5 100644
--- a/net/sched/sch_qfq.c
+++ b/net/sched/sch_qfq.c
@@ -203,6 +203,34 @@ out:
         return index;
 }
 
+/* Length of the next packet (0 if the queue is empty). */
+static unsigned int qdisc_peek_len(struct Qdisc *sch)
+{
+        struct sk_buff *skb;
+
+        skb = sch->ops->peek(sch);
+        return skb ? qdisc_pkt_len(skb) : 0;
+}
+
+static void qfq_deactivate_class(struct qfq_sched *, struct qfq_class *);
+static void qfq_activate_class(struct qfq_sched *q, struct qfq_class *cl,
+                               unsigned int len);
+
+static void qfq_update_class_params(struct qfq_sched *q, struct qfq_class *cl,
+                                    u32 lmax, u32 inv_w, int delta_w)
+{
+        int i;
+
+        /* update qfq-specific data */
+        cl->lmax = lmax;
+        cl->inv_w = inv_w;
+        i = qfq_calc_index(cl->inv_w, cl->lmax);
+
+        cl->grp = &q->groups[i];
+
+        q->wsum += delta_w;
+}
+
 static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
                             struct nlattr **tca, unsigned long *arg)
 {
@@ -250,6 +278,8 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
                 lmax = 1UL << QFQ_MTU_SHIFT;
 
         if (cl != NULL) {
+                bool need_reactivation = false;
+
                 if (tca[TCA_RATE]) {
                         err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
                                                     qdisc_root_sleeping_lock(sch),
@@ -258,12 +288,29 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
                                 return err;
                 }
 
-                if (inv_w != cl->inv_w) {
-                        sch_tree_lock(sch);
-                        q->wsum += delta_w;
-                        cl->inv_w = inv_w;
-                        sch_tree_unlock(sch);
+                if (lmax == cl->lmax && inv_w == cl->inv_w)
+                        return 0; /* nothing to update */
+
+                i = qfq_calc_index(inv_w, lmax);
+                sch_tree_lock(sch);
+                if (&q->groups[i] != cl->grp && cl->qdisc->q.qlen > 0) {
+                        /*
+                         * shift cl->F back, to not charge the
+                         * class for the not-yet-served head
+                         * packet
+                         */
+                        cl->F = cl->S;
+                        /* remove class from its slot in the old group */
+                        qfq_deactivate_class(q, cl);
+                        need_reactivation = true;
                 }
+
+                qfq_update_class_params(q, cl, lmax, inv_w, delta_w);
+
+                if (need_reactivation) /* activate in new group */
+                        qfq_activate_class(q, cl, qdisc_peek_len(cl->qdisc));
+                sch_tree_unlock(sch);
+
                 return 0;
         }
 
@@ -273,11 +320,8 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 
         cl->refcnt = 1;
         cl->common.classid = classid;
-        cl->lmax = lmax;
-        cl->inv_w = inv_w;
-        i = qfq_calc_index(cl->inv_w, cl->lmax);
 
-        cl->grp = &q->groups[i];
+        qfq_update_class_params(q, cl, lmax, inv_w, delta_w);
 
         cl->qdisc = qdisc_create_dflt(sch->dev_queue,
                                       &pfifo_qdisc_ops, classid);
@@ -294,7 +338,6 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
                         return err;
                 }
         }
-        q->wsum += weight;
 
         sch_tree_lock(sch);
         qdisc_class_hash_insert(&q->clhash, &cl->common);
@@ -711,15 +754,6 @@ static void qfq_update_eligible(struct qfq_sched *q, u64 old_V)
         }
 }
 
-/* What is length of next packet in queue (0 if queue is empty) */
-static unsigned int qdisc_peek_len(struct Qdisc *sch)
-{
-        struct sk_buff *skb;
-
-        skb = sch->ops->peek(sch);
-        return skb ? qdisc_pkt_len(skb) : 0;
-}
-
 /*
  * Updates the class, returns true if also the group needs to be updated.
  */
@@ -843,11 +877,8 @@ static void qfq_update_start(struct qfq_sched *q, struct qfq_class *cl)
 static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 {
         struct qfq_sched *q = qdisc_priv(sch);
-        struct qfq_group *grp;
         struct qfq_class *cl;
         int err;
-        u64 roundedS;
-        int s;
 
         cl = qfq_classify(skb, sch, &err);
         if (cl == NULL) {
@@ -876,11 +907,25 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
                 return err;
 
         /* If reach this point, queue q was idle */
-        grp = cl->grp;
+        qfq_activate_class(q, cl, qdisc_pkt_len(skb));
+
+        return err;
+}
+
+/*
+ * Handle class switch from idle to backlogged.
+ */
+static void qfq_activate_class(struct qfq_sched *q, struct qfq_class *cl,
+                               unsigned int pkt_len)
+{
+        struct qfq_group *grp = cl->grp;
+        u64 roundedS;
+        int s;
+
         qfq_update_start(q, cl);
 
         /* compute new finish time and rounded start. */
-        cl->F = cl->S + (u64)qdisc_pkt_len(skb) * cl->inv_w;
+        cl->F = cl->S + (u64)pkt_len * cl->inv_w;
         roundedS = qfq_round_down(cl->S, grp->slot_shift);
 
         /*
@@ -917,8 +962,6 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 
 skip_update:
         qfq_slot_insert(grp, cl, roundedS);
-
-        return err;
 }