Merge branch 'for-airlied' of git://people.freedesktop.org/~danvet/drm-intel into...

[deliverable/linux.git] / net / sched / sch_qfq.c

diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c
index 9af01f3df18c66b6325c8afe628758b56e306952..211a212170451c41f352f087dc9e0b3af9e8ae2c 100644 (file)
--- 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.
  */
@@ -831,7 +865,10 @@ static void qfq_update_start(struct qfq_sched *q, struct qfq_class *cl)
                if (mask) {
                        struct qfq_group *next = qfq_ffs(q, mask);
                        if (qfq_gt(roundedF, next->F)) {
-                               cl->S = next->F;
+                               if (qfq_gt(limit, next->F))
+                                       cl->S = next->F;
+                               else /* preserve timestamp correctness */
+                                       cl->S = limit;
                                return;
                        }
                }
@@ -843,11 +880,8 @@ 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 +910,25 @@ 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 +965,6 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 
 skip_update:
        qfq_slot_insert(grp, cl, roundedS);
-
-       return err;
 }