net-sched: sch_htb: remove child and sibling lists

Now that the qdisc isn't destroyed in hierarchical order anymore,
the only user of the child lists left is htb_parent_last_child().
This can be easily changed to use a counter of children to save
a few bytes.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 14 deletions

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index e7461a17d71e..128a5ab2e376 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -81,9 +81,8 @@ struct htb_class {
 
         /* topology */
         int level;              /* our level (see above) */
+        unsigned int children;
         struct htb_class *parent;       /* parent class */
-        struct list_head sibling;       /* sibling list item */
-        struct list_head children;      /* children list */
 
         union {
                 struct htb_class_leaf {
@@ -138,7 +137,6 @@ static inline long L2T(struct htb_class *cl, struct qdisc_rate_table *rate,
 }
 
 struct htb_sched {
-        struct list_head root;  /* root classes list */
         struct Qdisc_class_hash clhash;
         struct list_head drops[TC_HTB_NUMPRIO];/* active leaves (for drops) */
 
@@ -1020,7 +1018,6 @@ static int htb_init(struct Qdisc *sch, struct nlattr *opt)
                 return -EINVAL;
         }
 
-        INIT_LIST_HEAD(&q->root);
         err = qdisc_class_hash_init(&q->clhash);
         if (err < 0)
                 return err;
@@ -1175,12 +1172,9 @@ static inline int htb_parent_last_child(struct htb_class *cl)
         if (!cl->parent)
                 /* the root class */
                 return 0;
-
-        if (!(cl->parent->children.next == &cl->sibling &&
-                cl->parent->children.prev == &cl->sibling))
+        if (cl->parent->children > 1)
                 /* not the last child */
                 return 0;
-
         return 1;
 }
 
@@ -1259,7 +1253,7 @@ static int htb_delete(struct Qdisc *sch, unsigned long arg)
         // TODO: why don't allow to delete subtree ? references ? does
         // tc subsys quarantee us that in htb_destroy it holds no class
         // refs so that we can remove children safely there ?
-        if (!list_empty(&cl->children) || cl->filter_cnt)
+        if (cl->children || cl->filter_cnt)
                 return -EBUSY;
 
         if (!cl->level && htb_parent_last_child(cl)) {
@@ -1278,7 +1272,7 @@ static int htb_delete(struct Qdisc *sch, unsigned long arg)
 
         /* delete from hash and active; remainder in destroy_class */
         qdisc_class_hash_remove(&q->clhash, &cl->common);
-        list_del(&cl->sibling);
+        cl->parent->children--;
 
         if (cl->prio_activity)
                 htb_deactivate(q, cl);
@@ -1373,8 +1367,7 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
                                   &sch->dev->queue_lock,
                                   tca[TCA_RATE] ? : &est.nla);
                 cl->refcnt = 1;
-                INIT_LIST_HEAD(&cl->sibling);
-                INIT_LIST_HEAD(&cl->children);
+                cl->children = 0;
                 INIT_LIST_HEAD(&cl->un.leaf.drop_list);
                 RB_CLEAR_NODE(&cl->pq_node);
 
@@ -1420,8 +1413,8 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
 
                 /* attach to the hash list and parent's family */
                 qdisc_class_hash_insert(&q->clhash, &cl->common);
-                list_add_tail(&cl->sibling,
-                              parent ? &parent->children : &q->root);
+                if (parent)
+                        parent->children++;
         } else {
                 if (tca[TCA_RATE])
                         gen_replace_estimator(&cl->bstats, &cl->rate_est,