Merge branch 'sch_hfsc-fixes-cleanups'

Michal Soltys says:

====================
HFSC patches, part 1

It's revised version of part of the patches I submitted really, really long
time ago (back then I asked Patrick to ignore them as I found some issues
shortly after submitting).

Anyway this is the first set with very simple fixes/changes though some of them
relatively subtle (I tried to do very exhaustive commit messages explaining what
and why with those).

The patches are against net-next tree.

The second set will be heavier - or rather with more complex explanations, among those I have:

- a fix to subtle issue introduced in
  http://permalink.gmane.org/gmane.linux.kernel.commits.2-4/8281
  along with simplifying related stuff
- update times to 96 bits (which allows to "just" use 32 bit shifts and
  improves curve definition accuracy at more extreme low/high speeds)
- add curve "merging" instead of just selecting in convex case (computations
  mirror those from concave intersection)

But these are eventually for later.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 8cb5eff..dff92ea 100644 (file)
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -130,7 +130,6 @@ struct hfsc_class {
        struct rb_node vt_node;         /* parent's vt_tree member */
        struct rb_root cf_tree;         /* active children sorted by cl_f */
        struct rb_node cf_node;         /* parent's cf_heap member */
-       struct list_head dlist;         /* drop list member */
 
        u64     cl_total;               /* total work in bytes */
        u64     cl_cumul;               /* cumulative work in bytes done by
@@ -177,8 +176,6 @@ struct hfsc_sched {
        struct hfsc_class root;                 /* root class */
        struct Qdisc_class_hash clhash;         /* class hash */
        struct rb_root eligible;                /* eligible tree */
-       struct list_head droplist;              /* active leaf class list (for
-                                                  dropping) */
        struct qdisc_watchdog watchdog;         /* watchdog timer */
 };
 
@@ -781,6 +778,20 @@ update_vf(struct hfsc_class *cl, unsigned int len, u64 cur_time)
                else
                        go_passive = 0;
 
+               /* update vt */
+               cl->cl_vt = rtsc_y2x(&cl->cl_virtual, cl->cl_total)
+                           - cl->cl_vtoff + cl->cl_vtadj;
+
+               /*
+                * if vt of the class is smaller than cvtmin,
+                * the class was skipped in the past due to non-fit.
+                * if so, we need to adjust vtadj.
+                */
+               if (cl->cl_vt < cl->cl_parent->cl_cvtmin) {
+                       cl->cl_vtadj += cl->cl_parent->cl_cvtmin - cl->cl_vt;
+                       cl->cl_vt = cl->cl_parent->cl_cvtmin;
+               }
+
                if (go_passive) {
                        /* no more active child, going passive */
 
@@ -797,25 +808,10 @@ update_vf(struct hfsc_class *cl, unsigned int len, u64 cur_time)
                        continue;
                }
 
-               /*
-                * update vt and f
-                */
-               cl->cl_vt = rtsc_y2x(&cl->cl_virtual, cl->cl_total)
-                           - cl->cl_vtoff + cl->cl_vtadj;
-
-               /*
-                * if vt of the class is smaller than cvtmin,
-                * the class was skipped in the past due to non-fit.
-                * if so, we need to adjust vtadj.
-                */
-               if (cl->cl_vt < cl->cl_parent->cl_cvtmin) {
-                       cl->cl_vtadj += cl->cl_parent->cl_cvtmin - cl->cl_vt;
-                       cl->cl_vt = cl->cl_parent->cl_cvtmin;
-               }
-
                /* update the vt tree */
                vttree_update(cl);
 
+               /* update f */
                if (cl->cl_flags & HFSC_USC) {
                        cl->cl_myf = cl->cl_myfadj + rtsc_y2x(&cl->cl_ulimit,
                                                              cl->cl_total);
@@ -858,7 +854,6 @@ set_active(struct hfsc_class *cl, unsigned int len)
        if (cl->cl_flags & HFSC_FSC)
                init_vf(cl, len);
 
-       list_add_tail(&cl->dlist, &cl->sched->droplist);
 }
 
 static void
@@ -867,8 +862,6 @@ set_passive(struct hfsc_class *cl)
        if (cl->cl_flags & HFSC_RSC)
                eltree_remove(cl);
 
-       list_del(&cl->dlist);
-
        /*
         * vttree is now handled in update_vf() so that update_vf(cl, 0, 0)
         * needs to be called explicitly to remove a class from vttree.
@@ -882,7 +875,7 @@ qdisc_peek_len(struct Qdisc *sch)
        unsigned int len;
 
        skb = sch->ops->peek(sch);
-       if (skb == NULL) {
+       if (unlikely(skb == NULL)) {
                qdisc_warn_nonwc("qdisc_peek_len", sch);
                return 0;
        }
@@ -947,7 +940,7 @@ static void
 hfsc_change_fsc(struct hfsc_class *cl, struct tc_service_curve *fsc)
 {
        sc2isc(fsc, &cl->cl_fsc);
-       rtsc_init(&cl->cl_virtual, &cl->cl_fsc, cl->cl_vt, cl->cl_total);
+       rtsc_init(&cl->cl_virtual, &cl->cl_fsc, cl->cl_vtoff + cl->cl_vt, cl->cl_total);
        cl->cl_flags |= HFSC_FSC;
 }
 
@@ -1443,7 +1436,6 @@ hfsc_init_qdisc(struct Qdisc *sch, struct nlattr *opt)
        if (err < 0)
                return err;
        q->eligible = RB_ROOT;
-       INIT_LIST_HEAD(&q->droplist);
 
        q->root.cl_common.classid = sch->handle;
        q->root.refcnt  = 1;
@@ -1527,7 +1519,6 @@ hfsc_reset_qdisc(struct Qdisc *sch)
                        hfsc_reset_class(cl);
        }
        q->eligible = RB_ROOT;
-       INIT_LIST_HEAD(&q->droplist);
        qdisc_watchdog_cancel(&q->watchdog);
        sch->qstats.backlog = 0;
        sch->q.qlen = 0;
@@ -1594,8 +1585,17 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
                return err;
        }
 
-       if (cl->qdisc->q.qlen == 1)
+       if (cl->qdisc->q.qlen == 1) {
                set_active(cl, qdisc_pkt_len(skb));
+               /*
+                * If this is the first packet, isolate the head so an eventual
+                * head drop before the first dequeue operation has no chance
+                * to invalidate the deadline.
+                */
+               if (cl->cl_flags & HFSC_RSC)
+                       cl->qdisc->ops->peek(cl->qdisc);
+
+       }
 
        qdisc_qstats_backlog_inc(sch, skb);
        sch->q.qlen++;