net: sched: introduce tcf block infractructure

Currently, the filter chains are direcly put into the private structures
of qdiscs. In order to be able to have multiple chains per qdisc and to
allow filter chains sharing among qdiscs, there is a need for common
object that would hold the chains. This introduces such object and calls
it "tcf_block".

Helpers to get and put the blocks are provided to be called from
individual qdisc code. Also, the original filter_list pointers are left
in qdisc privs to allow the entry into tcf_block processing without any
added overhead of possible multiple pointer dereference on fast path.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 38 insertions, 10 deletions

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index af58bbef6610..d30116f77156 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -129,7 +129,8 @@ static inline u32 tcf_auto_prio(struct tcf_proto *tp)
 }
 
 static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
-                                          u32 prio, u32 parent, struct Qdisc *q)
+                                          u32 prio, u32 parent, struct Qdisc *q,
+                                          struct tcf_block *block)
 {
         struct tcf_proto *tp;
         int err;
@@ -165,6 +166,7 @@ static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
         tp->prio = prio;
         tp->classid = parent;
         tp->q = q;
+        tp->block = block;
 
         err = tp->ops->init(tp);
         if (err) {
@@ -185,7 +187,7 @@ static void tcf_proto_destroy(struct tcf_proto *tp)
         kfree_rcu(tp, rcu);
 }
 
-void tcf_destroy_chain(struct tcf_proto __rcu **fl)
+static void tcf_destroy_chain(struct tcf_proto __rcu **fl)
 {
         struct tcf_proto *tp;
 
@@ -194,7 +196,28 @@ void tcf_destroy_chain(struct tcf_proto __rcu **fl)
                 tcf_proto_destroy(tp);
         }
 }
-EXPORT_SYMBOL(tcf_destroy_chain);
+
+int tcf_block_get(struct tcf_block **p_block,
+                  struct tcf_proto __rcu **p_filter_chain)
+{
+        struct tcf_block *block = kzalloc(sizeof(*block), GFP_KERNEL);
+
+        if (!block)
+                return -ENOMEM;
+        block->p_filter_chain = p_filter_chain;
+        *p_block = block;
+        return 0;
+}
+EXPORT_SYMBOL(tcf_block_get);
+
+void tcf_block_put(struct tcf_block *block)
+{
+        if (!block)
+                return;
+        tcf_destroy_chain(block->p_filter_chain);
+        kfree(block);
+}
+EXPORT_SYMBOL(tcf_block_put);
 
 /* Main classifier routine: scans classifier chain attached
  * to this qdisc, (optionally) tests for protocol and asks
@@ -260,6 +283,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
         struct Qdisc  *q;
         struct tcf_proto __rcu **back;
         struct tcf_proto __rcu **chain;
+        struct tcf_block *block;
         struct tcf_proto *next;
         struct tcf_proto *tp;
         const struct Qdisc_class_ops *cops;
@@ -328,7 +352,7 @@ replay:
         if (!cops)
                 return -EINVAL;
 
-        if (cops->tcf_chain == NULL)
+        if (!cops->tcf_block)
                 return -EOPNOTSUPP;
 
         /* Do we search for filter, attached to class? */
@@ -339,11 +363,13 @@ replay:
         }
 
         /* And the last stroke */
-        chain = cops->tcf_chain(q, cl);
-        if (chain == NULL) {
+        block = cops->tcf_block(q, cl);
+        if (!block) {
                 err = -EINVAL;
                 goto errout;
         }
+        chain = block->p_filter_chain;
+
         if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {
                 tfilter_notify_chain(net, skb, n, chain, RTM_DELTFILTER);
                 tcf_destroy_chain(chain);
@@ -387,7 +413,7 @@ replay:
                         nprio = TC_H_MAJ(tcf_auto_prio(rtnl_dereference(*back)));
 
                 tp = tcf_proto_create(nla_data(tca[TCA_KIND]),
-                                      protocol, nprio, parent, q);
+                                      protocol, nprio, parent, q, block);
                 if (IS_ERR(tp)) {
                         err = PTR_ERR(tp);
                         goto errout;
@@ -556,6 +582,7 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
         int s_t;
         struct net_device *dev;
         struct Qdisc *q;
+        struct tcf_block *block;
         struct tcf_proto *tp, __rcu **chain;
         struct tcmsg *tcm = nlmsg_data(cb->nlh);
         unsigned long cl = 0;
@@ -577,16 +604,17 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
         cops = q->ops->cl_ops;
         if (!cops)
                 goto errout;
-        if (cops->tcf_chain == NULL)
+        if (!cops->tcf_block)
                 goto errout;
         if (TC_H_MIN(tcm->tcm_parent)) {
                 cl = cops->get(q, tcm->tcm_parent);
                 if (cl == 0)
                         goto errout;
         }
-        chain = cops->tcf_chain(q, cl);
-        if (chain == NULL)
+        block = cops->tcf_block(q, cl);
+        if (!block)
                 goto errout;
+        chain = block->p_filter_chain;
 
         s_t = cb->args[0];