net_sched: add reverse binding for tc class

TC filters when used as classifiers are bound to TC classes.
However, there is a hidden difference when adding them in different
orders:

1. If we add tc classes before its filters, everything is fine.
   Logically, the classes exist before we specify their ID's in
   filters, it is easy to bind them together, just as in the current
   code base.

2. If we add tc filters before the tc classes they bind, we have to
   do dynamic lookup in fast path. What's worse, this happens all
   the time not just once, because on fast path tcf_result is passed
   on stack, there is no way to propagate back to the one in tc filters.

This hidden difference hurts performance silently if we have many tc
classes in hierarchy.

This patch intends to close this gap by doing the reverse binding when
we create a new class, in this case we can actually search all the
filters in its parent, match and fixup by classid. And because
tcf_result is specific to each type of tc filter, we have to introduce
a new ops for each filter to tell how to bind the class.

Note, we still can NOT totally get rid of those class lookup in
->enqueue() because cgroup and flow filters have no way to determine
the classid at setup time, they still have to go through dynamic lookup.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index c30b634c5f82b1803d1c9c14ddf62ec8fecaed14..d6247a3c40df1209bdf50aacdca5d260c6962e4c 100644 (file)
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -217,6 +217,7 @@ struct tcf_proto_ops {
                                        void **, bool);
        int                     (*delete)(struct tcf_proto*, void *, bool*);
        void                    (*walk)(struct tcf_proto*, struct tcf_walker *arg);
+       void                    (*bind_class)(void *, u32, unsigned long);
 
        /* rtnetlink specific */
        int                     (*dump)(struct net*, struct tcf_proto*, void *,

diff --git a/net/sched/cls_basic.c b/net/sched/cls_basic.c
index 73cc7f167a384fee6ec35fd99fd0146f49df9499..d89ebafd22390238b868425cb5a8bbd8dec2c268 100644 (file)
--- a/net/sched/cls_basic.c
+++ b/net/sched/cls_basic.c
@@ -235,6 +235,14 @@ skip:
        }
 }
 
+static void basic_bind_class(void *fh, u32 classid, unsigned long cl)
+{
+       struct basic_filter *f = fh;
+
+       if (f && f->res.classid == classid)
+               f->res.class = cl;
+}
+
 static int basic_dump(struct net *net, struct tcf_proto *tp, void *fh,
                      struct sk_buff *skb, struct tcmsg *t)
 {
@@ -280,6 +288,7 @@ static struct tcf_proto_ops cls_basic_ops __read_mostly = {
        .delete         =       basic_delete,
        .walk           =       basic_walk,
        .dump           =       basic_dump,
+       .bind_class     =       basic_bind_class,
        .owner          =       THIS_MODULE,
 };
 

diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c
index 6f2dffe30f25a0d4beb30a33a6861159355abd3c..520c5027646aea5146f22d7898acfbc7dee3385a 100644 (file)
--- a/net/sched/cls_bpf.c
+++ b/net/sched/cls_bpf.c
@@ -607,6 +607,14 @@ nla_put_failure:
        return -1;
 }
 
+static void cls_bpf_bind_class(void *fh, u32 classid, unsigned long cl)
+{
+       struct cls_bpf_prog *prog = fh;
+
+       if (prog && prog->res.classid == classid)
+               prog->res.class = cl;
+}
+
 static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 {
        struct cls_bpf_head *head = rtnl_dereference(tp->root);
@@ -635,6 +643,7 @@ static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
        .delete         =       cls_bpf_delete,
        .walk           =       cls_bpf_walk,
        .dump           =       cls_bpf_dump,
+       .bind_class     =       cls_bpf_bind_class,
 };
 
 static int __init cls_bpf_init_mod(void)

diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 3d041d279b9292a0e98576cc744ffc9a249c7fcb..1a267e77c6de93ad58fd609426d3daef27f39c54 100644 (file)
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -1351,6 +1351,14 @@ nla_put_failure:
        return -1;
 }
 
+static void fl_bind_class(void *fh, u32 classid, unsigned long cl)
+{
+       struct cls_fl_filter *f = fh;
+
+       if (f && f->res.classid == classid)
+               f->res.class = cl;
+}
+
 static struct tcf_proto_ops cls_fl_ops __read_mostly = {
        .kind           = "flower",
        .classify       = fl_classify,
@@ -1361,6 +1369,7 @@ static struct tcf_proto_ops cls_fl_ops __read_mostly = {
        .delete         = fl_delete,
        .walk           = fl_walk,
        .dump           = fl_dump,
+       .bind_class     = fl_bind_class,
        .owner          = THIS_MODULE,
 };
 

diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c
index 192255ec50bd7930e20eb2ca6bf12f0e922a7a74..941245ad07fd4b8bb4fd97cd84fac8791c571276 100644 (file)
--- a/net/sched/cls_fw.c
+++ b/net/sched/cls_fw.c
@@ -412,6 +412,14 @@ nla_put_failure:
        return -1;
 }
 
+static void fw_bind_class(void *fh, u32 classid, unsigned long cl)
+{
+       struct fw_filter *f = fh;
+
+       if (f && f->res.classid == classid)
+               f->res.class = cl;
+}
+
 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
        .kind           =       "fw",
        .classify       =       fw_classify,
@@ -422,6 +430,7 @@ static struct tcf_proto_ops cls_fw_ops __read_mostly = {
        .delete         =       fw_delete,
        .walk           =       fw_walk,
        .dump           =       fw_dump,
+       .bind_class     =       fw_bind_class,
        .owner          =       THIS_MODULE,
 };
 

diff --git a/net/sched/cls_matchall.c b/net/sched/cls_matchall.c
index d4dc387f7a563b283fc62a819014e32d26463109..21cc45caf8424a2d9ba75558c11fe1dc8170cd48 100644 (file)
--- a/net/sched/cls_matchall.c
+++ b/net/sched/cls_matchall.c
@@ -251,6 +251,14 @@ nla_put_failure:
        return -1;
 }
 
+static void mall_bind_class(void *fh, u32 classid, unsigned long cl)
+{
+       struct cls_mall_head *head = fh;
+
+       if (head && head->res.classid == classid)
+               head->res.class = cl;
+}
+
 static struct tcf_proto_ops cls_mall_ops __read_mostly = {
        .kind           = "matchall",
        .classify       = mall_classify,
@@ -261,6 +269,7 @@ static struct tcf_proto_ops cls_mall_ops __read_mostly = {
        .delete         = mall_delete,
        .walk           = mall_walk,
        .dump           = mall_dump,
+       .bind_class     = mall_bind_class,
        .owner          = THIS_MODULE,
 };
 

diff --git a/net/sched/cls_route.c b/net/sched/cls_route.c
index 3b70982394ce43a81ef9ac0e52428f53d824c915..9ddde65915d22615aa93036f01ae0368783c94f6 100644 (file)
--- a/net/sched/cls_route.c
+++ b/net/sched/cls_route.c
@@ -624,6 +624,14 @@ nla_put_failure:
        return -1;
 }
 
+static void route4_bind_class(void *fh, u32 classid, unsigned long cl)
+{
+       struct route4_filter *f = fh;
+
+       if (f && f->res.classid == classid)
+               f->res.class = cl;
+}
+
 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
        .kind           =       "route",
        .classify       =       route4_classify,
@@ -634,6 +642,7 @@ static struct tcf_proto_ops cls_route4_ops __read_mostly = {
        .delete         =       route4_delete,
        .walk           =       route4_walk,
        .dump           =       route4_dump,
+       .bind_class     =       route4_bind_class,
        .owner          =       THIS_MODULE,
 };
 

diff --git a/net/sched/cls_rsvp.h b/net/sched/cls_rsvp.h
index 26203ff817f3185a9af9c56d710fdbe23e387121..98c05db85bcbc6e1bfce099686d7fa88590190b1 100644 (file)
--- a/net/sched/cls_rsvp.h
+++ b/net/sched/cls_rsvp.h
@@ -723,6 +723,14 @@ nla_put_failure:
        return -1;
 }
 
+static void rsvp_bind_class(void *fh, u32 classid, unsigned long cl)
+{
+       struct rsvp_filter *f = fh;
+
+       if (f && f->res.classid == classid)
+               f->res.class = cl;
+}
+
 static struct tcf_proto_ops RSVP_OPS __read_mostly = {
        .kind           =       RSVP_ID,
        .classify       =       rsvp_classify,
@@ -733,6 +741,7 @@ static struct tcf_proto_ops RSVP_OPS __read_mostly = {
        .delete         =       rsvp_delete,
        .walk           =       rsvp_walk,
        .dump           =       rsvp_dump,
+       .bind_class     =       rsvp_bind_class,
        .owner          =       THIS_MODULE,
 };
 

diff --git a/net/sched/cls_tcindex.c b/net/sched/cls_tcindex.c
index fb281b9b2c52cc89682d80400fa2a934aa4d0150..14a7e08b2fa9e2f8a3551f6dbc1fb38f1e8df579 100644 (file)
--- a/net/sched/cls_tcindex.c
+++ b/net/sched/cls_tcindex.c
@@ -606,6 +606,14 @@ nla_put_failure:
        return -1;
 }
 
+static void tcindex_bind_class(void *fh, u32 classid, unsigned long cl)
+{
+       struct tcindex_filter_result *r = fh;
+
+       if (r && r->res.classid == classid)
+               r->res.class = cl;
+}
+
 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
        .kind           =       "tcindex",
        .classify       =       tcindex_classify,
@@ -616,6 +624,7 @@ static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
        .delete         =       tcindex_delete,
        .walk           =       tcindex_walk,
        .dump           =       tcindex_dump,
+       .bind_class     =       tcindex_bind_class,
        .owner          =       THIS_MODULE,
 };
 

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 99ea4c74dd5b602979678648365e8fb1aaf18a0d..10b8d851fc6be96c761bea127776b84d21b4fc05 100644 (file)
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -1112,6 +1112,14 @@ static void u32_walk(struct tcf_proto *tp, struct tcf_walker *arg)
        }
 }
 
+static void u32_bind_class(void *fh, u32 classid, unsigned long cl)
+{
+       struct tc_u_knode *n = fh;
+
+       if (n && n->res.classid == classid)
+               n->res.class = cl;
+}
+
 static int u32_dump(struct net *net, struct tcf_proto *tp, void *fh,
                    struct sk_buff *skb, struct tcmsg *t)
 {
@@ -1242,6 +1250,7 @@ static struct tcf_proto_ops cls_u32_ops __read_mostly = {
        .delete         =       u32_delete,
        .walk           =       u32_walk,
        .dump           =       u32_dump,
+       .bind_class     =       u32_bind_class,
        .owner          =       THIS_MODULE,
 };
 

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index e7f8e4bfd4ec35ca25acef2d927dc787615d081c..929b024f41ba02dcf3296e13f5442e1d787f1d82 100644 (file)
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -35,6 +35,7 @@
 #include <net/sock.h>
 #include <net/netlink.h>
 #include <net/pkt_sched.h>
+#include <net/pkt_cls.h>
 
 /*
 
@@ -1648,6 +1649,64 @@ static int tclass_del_notify(struct net *net,
                              n->nlmsg_flags & NLM_F_ECHO);
 }
 
+#ifdef CONFIG_NET_CLS
+
+struct tcf_bind_args {
+       struct tcf_walker w;
+       u32 classid;
+       unsigned long cl;
+};
+
+static int tcf_node_bind(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
+{
+       struct tcf_bind_args *a = (void *)arg;
+
+       if (tp->ops->bind_class) {
+               tcf_tree_lock(tp);
+               tp->ops->bind_class(n, a->classid, a->cl);
+               tcf_tree_unlock(tp);
+       }
+       return 0;
+}
+
+static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
+                          unsigned long new_cl)
+{
+       const struct Qdisc_class_ops *cops = q->ops->cl_ops;
+       struct tcf_block *block;
+       struct tcf_chain *chain;
+       unsigned long cl;
+
+       cl = cops->find(q, portid);
+       if (!cl)
+               return;
+       block = cops->tcf_block(q, cl);
+       if (!block)
+               return;
+       list_for_each_entry(chain, &block->chain_list, list) {
+               struct tcf_proto *tp;
+
+               for (tp = rtnl_dereference(chain->filter_chain);
+                    tp; tp = rtnl_dereference(tp->next)) {
+                       struct tcf_bind_args arg = {};
+
+                       arg.w.fn = tcf_node_bind;
+                       arg.classid = clid;
+                       arg.cl = new_cl;
+                       tp->ops->walk(tp, &arg.w);
+               }
+       }
+}
+
+#else
+
+static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
+                          unsigned long new_cl)
+{
+}
+
+#endif
+
 static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n,
                         struct netlink_ext_ack *extack)
 {
@@ -1753,6 +1812,8 @@ static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n,
                        break;
                case RTM_DELTCLASS:
                        err = tclass_del_notify(net, cops, skb, n, q, cl);
+                       /* Unbind the class with flilters with 0 */
+                       tc_bind_tclass(q, portid, clid, 0);
                        goto out;
                case RTM_GETTCLASS:
                        err = tclass_notify(net, skb, n, q, cl, RTM_NEWTCLASS);
@@ -1767,9 +1828,12 @@ static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n,
        err = -EOPNOTSUPP;
        if (cops->change)
                err = cops->change(q, clid, portid, tca, &new_cl);
-       if (err == 0)
+       if (err == 0) {
                tclass_notify(net, skb, n, q, new_cl, RTM_NEWTCLASS);
-
+               /* We just create a new class, need to do reverse binding. */
+               if (cl != new_cl)
+                       tc_bind_tclass(q, portid, clid, new_cl);
+       }
 out:
        return err;
 }