2 files changed, 146 insertions, 0 deletions

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index a87fc0312edc..073f2580b83b 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -167,6 +167,48 @@ extern void qdisc_unlock_tree(struct net_device *dev);
 extern struct Qdisc noop_qdisc;
 extern struct Qdisc_ops noop_qdisc_ops;
 
+struct Qdisc_class_common
+{
+        u32                     classid;
+        struct hlist_node       hnode;
+};
+
+struct Qdisc_class_hash
+{
+        struct hlist_head       *hash;
+        unsigned int            hashsize;
+        unsigned int            hashmask;
+        unsigned int            hashelems;
+};
+
+static inline unsigned int qdisc_class_hash(u32 id, u32 mask)
+{
+        id ^= id >> 8;
+        id ^= id >> 4;
+        return id & mask;
+}
+
+static inline struct Qdisc_class_common *
+qdisc_class_find(struct Qdisc_class_hash *hash, u32 id)
+{
+        struct Qdisc_class_common *cl;
+        struct hlist_node *n;
+        unsigned int h;
+
+        h = qdisc_class_hash(id, hash->hashmask);
+        hlist_for_each_entry(cl, n, &hash->hash[h], hnode) {
+                if (cl->classid == id)
+                        return cl;
+        }
+        return NULL;
+}
+
+extern int qdisc_class_hash_init(struct Qdisc_class_hash *);
+extern void qdisc_class_hash_insert(struct Qdisc_class_hash *, struct Qdisc_class_common *);
+extern void qdisc_class_hash_remove(struct Qdisc_class_hash *, struct Qdisc_class_common *);
+extern void qdisc_class_hash_grow(struct Qdisc *, struct Qdisc_class_hash *);
+extern void qdisc_class_hash_destroy(struct Qdisc_class_hash *);
+
 extern void dev_init_scheduler(struct net_device *dev);
 extern void dev_shutdown(struct net_device *dev);
 extern void dev_activate(struct net_device *dev);
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 10f01ad04380..e9ebc7af049e 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -316,6 +316,110 @@ void qdisc_watchdog_cancel(struct qdisc_watchdog *wd)
 }
 EXPORT_SYMBOL(qdisc_watchdog_cancel);
 
+struct hlist_head *qdisc_class_hash_alloc(unsigned int n)
+{
+        unsigned int size = n * sizeof(struct hlist_head), i;
+        struct hlist_head *h;
+
+        if (size <= PAGE_SIZE)
+                h = kmalloc(size, GFP_KERNEL);
+        else
+                h = (struct hlist_head *)
+                        __get_free_pages(GFP_KERNEL, get_order(size));
+
+        if (h != NULL) {
+                for (i = 0; i < n; i++)
+                        INIT_HLIST_HEAD(&h[i]);
+        }
+        return h;
+}
+
+static void qdisc_class_hash_free(struct hlist_head *h, unsigned int n)
+{
+        unsigned int size = n * sizeof(struct hlist_head);
+
+        if (size <= PAGE_SIZE)
+                kfree(h);
+        else
+                free_pages((unsigned long)h, get_order(size));
+}
+
+void qdisc_class_hash_grow(struct Qdisc *sch, struct Qdisc_class_hash *clhash)
+{
+        struct Qdisc_class_common *cl;
+        struct hlist_node *n, *next;
+        struct hlist_head *nhash, *ohash;
+        unsigned int nsize, nmask, osize;
+        unsigned int i, h;
+
+        /* Rehash when load factor exceeds 0.75 */
+        if (clhash->hashelems * 4 <= clhash->hashsize * 3)
+                return;
+        nsize = clhash->hashsize * 2;
+        nmask = nsize - 1;
+        nhash = qdisc_class_hash_alloc(nsize);
+        if (nhash == NULL)
+                return;
+
+        ohash = clhash->hash;
+        osize = clhash->hashsize;
+
+        sch_tree_lock(sch);
+        for (i = 0; i < osize; i++) {
+                hlist_for_each_entry_safe(cl, n, next, &ohash[i], hnode) {
+                        h = qdisc_class_hash(cl->classid, nmask);
+                        hlist_add_head(&cl->hnode, &nhash[h]);
+                }
+        }
+        clhash->hash     = nhash;
+        clhash->hashsize = nsize;
+        clhash->hashmask = nmask;
+        sch_tree_unlock(sch);
+
+        qdisc_class_hash_free(ohash, osize);
+}
+EXPORT_SYMBOL(qdisc_class_hash_grow);
+
+int qdisc_class_hash_init(struct Qdisc_class_hash *clhash)
+{
+        unsigned int size = 4;
+
+        clhash->hash = qdisc_class_hash_alloc(size);
+        if (clhash->hash == NULL)
+                return -ENOMEM;
+        clhash->hashsize  = size;
+        clhash->hashmask  = size - 1;
+        clhash->hashelems = 0;
+        return 0;
+}
+EXPORT_SYMBOL(qdisc_class_hash_init);
+
+void qdisc_class_hash_destroy(struct Qdisc_class_hash *clhash)
+{
+        qdisc_class_hash_free(clhash->hash, clhash->hashsize);
+}
+EXPORT_SYMBOL(qdisc_class_hash_destroy);
+
+void qdisc_class_hash_insert(struct Qdisc_class_hash *clhash,
+                             struct Qdisc_class_common *cl)
+{
+        unsigned int h;
+
+        INIT_HLIST_NODE(&cl->hnode);
+        h = qdisc_class_hash(cl->classid, clhash->hashmask);
+        hlist_add_head(&cl->hnode, &clhash->hash[h]);
+        clhash->hashelems++;
+}
+EXPORT_SYMBOL(qdisc_class_hash_insert);
+
+void qdisc_class_hash_remove(struct Qdisc_class_hash *clhash,
+                             struct Qdisc_class_common *cl)
+{
+        hlist_del(&cl->hnode);
+        clhash->hashelems--;
+}
+EXPORT_SYMBOL(qdisc_class_hash_remove);
+
 /* Allocate an unique handle from space managed by kernel */
 
 static u32 qdisc_alloc_handle(struct net_device *dev)