1 files changed, 45 insertions, 21 deletions

diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c
index e9a77f621c3d..d51852bba01c 100644
--- a/net/sched/sch_qfq.c
+++ b/net/sched/sch_qfq.c
@@ -298,6 +298,10 @@ static void qfq_update_agg(struct qfq_sched *q, struct qfq_aggregate *agg,
             new_num_classes == q->max_agg_classes - 1) /* agg no more full */
                 hlist_add_head(&agg->nonfull_next, &q->nonfull_aggs);
 
+        /* The next assignment may let
+         * agg->initial_budget > agg->budgetmax
+         * hold, we will take it into account in charge_actual_service().
+         */
         agg->budgetmax = new_num_classes * agg->lmax;
         new_agg_weight = agg->class_weight * new_num_classes;
         agg->inv_w = ONE_FP/new_agg_weight;
@@ -817,7 +821,7 @@ static void qfq_make_eligible(struct qfq_sched *q)
         unsigned long old_vslot = q->oldV >> q->min_slot_shift;
 
         if (vslot != old_vslot) {
-                unsigned long mask = (1UL << fls(vslot ^ old_vslot)) - 1;
+                unsigned long mask = (1ULL << fls(vslot ^ old_vslot)) - 1;
                 qfq_move_groups(q, mask, IR, ER);
                 qfq_move_groups(q, mask, IB, EB);
         }
@@ -988,12 +992,23 @@ static inline struct sk_buff *qfq_peek_skb(struct qfq_aggregate *agg,
 /* Update F according to the actual service received by the aggregate. */
 static inline void charge_actual_service(struct qfq_aggregate *agg)
 {
-        /* compute the service received by the aggregate */
-        u32 service_received = agg->initial_budget - agg->budget;
+        /* Compute the service received by the aggregate, taking into
+         * account that, after decreasing the number of classes in
+         * agg, it may happen that
+         * agg->initial_budget - agg->budget > agg->bugdetmax
+         */
+        u32 service_received = min(agg->budgetmax,
+                                   agg->initial_budget - agg->budget);
 
         agg->F = agg->S + (u64)service_received * agg->inv_w;
 }
 
+static inline void qfq_update_agg_ts(struct qfq_sched *q,
+                                     struct qfq_aggregate *agg,
+                                     enum update_reason reason);
+
+static void qfq_schedule_agg(struct qfq_sched *q, struct qfq_aggregate *agg);
+
 static struct sk_buff *qfq_dequeue(struct Qdisc *sch)
 {
         struct qfq_sched *q = qdisc_priv(sch);
@@ -1021,7 +1036,7 @@ static struct sk_buff *qfq_dequeue(struct Qdisc *sch)
                 in_serv_agg->initial_budget = in_serv_agg->budget =
                         in_serv_agg->budgetmax;
 
-                if (!list_empty(&in_serv_agg->active))
+                if (!list_empty(&in_serv_agg->active)) {
                         /*
                          * Still active: reschedule for
                          * service. Possible optimization: if no other
@@ -1032,8 +1047,9 @@ static struct sk_buff *qfq_dequeue(struct Qdisc *sch)
                          * handle it, we would need to maintain an
                          * extra num_active_aggs field.
                         */
-                        qfq_activate_agg(q, in_serv_agg, requeue);
-                else if (sch->q.qlen == 0) { /* no aggregate to serve */
+                        qfq_update_agg_ts(q, in_serv_agg, requeue);
+                        qfq_schedule_agg(q, in_serv_agg);
+                } else if (sch->q.qlen == 0) { /* no aggregate to serve */
                         q->in_serv_agg = NULL;
                         return NULL;
                 }
@@ -1052,7 +1068,15 @@ static struct sk_buff *qfq_dequeue(struct Qdisc *sch)
         qdisc_bstats_update(sch, skb);
 
         agg_dequeue(in_serv_agg, cl, len);
-        in_serv_agg->budget -= len;
+        /* If lmax is lowered, through qfq_change_class, for a class
+         * owning pending packets with larger size than the new value
+         * of lmax, then the following condition may hold.
+         */
+        if (unlikely(in_serv_agg->budget < len))
+                in_serv_agg->budget = 0;
+        else
+                in_serv_agg->budget -= len;
+
         q->V += (u64)len * IWSUM;
         pr_debug("qfq dequeue: len %u F %lld now %lld\n",
                  len, (unsigned long long) in_serv_agg->F,
@@ -1217,17 +1241,11 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
         cl->deficit = agg->lmax;
         list_add_tail(&cl->alist, &agg->active);
 
-        if (list_first_entry(&agg->active, struct qfq_class, alist) != cl)
-                return err; /* aggregate was not empty, nothing else to do */
+        if (list_first_entry(&agg->active, struct qfq_class, alist) != cl ||
+            q->in_serv_agg == agg)
+                return err; /* non-empty or in service, nothing else to do */
 
-        /* recharge budget */
-        agg->initial_budget = agg->budget = agg->budgetmax;
-
-        qfq_update_agg_ts(q, agg, enqueue);
-        if (q->in_serv_agg == NULL)
-                q->in_serv_agg = agg;
-        else if (agg != q->in_serv_agg)
-                qfq_schedule_agg(q, agg);
+        qfq_activate_agg(q, agg, enqueue);
 
         return err;
 }
@@ -1261,7 +1279,8 @@ static void qfq_schedule_agg(struct qfq_sched *q, struct qfq_aggregate *agg)
                 /* group was surely ineligible, remove */
                 __clear_bit(grp->index, &q->bitmaps[IR]);
                 __clear_bit(grp->index, &q->bitmaps[IB]);
-        } else if (!q->bitmaps[ER] && qfq_gt(roundedS, q->V))
+        } else if (!q->bitmaps[ER] && qfq_gt(roundedS, q->V) &&
+                   q->in_serv_agg == NULL)
                 q->V = roundedS;
 
         grp->S = roundedS;
@@ -1284,8 +1303,15 @@ skip_update:
 static void qfq_activate_agg(struct qfq_sched *q, struct qfq_aggregate *agg,
                              enum update_reason reason)
 {
+        agg->initial_budget = agg->budget = agg->budgetmax; /* recharge budg. */
+
         qfq_update_agg_ts(q, agg, reason);
-        qfq_schedule_agg(q, agg);
+        if (q->in_serv_agg == NULL) { /* no aggr. in service or scheduled */
+                q->in_serv_agg = agg; /* start serving this aggregate */
+                 /* update V: to be in service, agg must be eligible */
+                q->oldV = q->V = agg->S;
+        } else if (agg != q->in_serv_agg)
+                qfq_schedule_agg(q, agg);
 }
 
 static void qfq_slot_remove(struct qfq_sched *q, struct qfq_group *grp,
@@ -1357,8 +1383,6 @@ static void qfq_deactivate_agg(struct qfq_sched *q, struct qfq_aggregate *agg)
                         __set_bit(grp->index, &q->bitmaps[s]);
                 }
         }
-
-        qfq_update_eligible(q);
 }
 
 static void qfq_qlen_notify(struct Qdisc *sch, unsigned long arg)