From: Jiri Pirko <j...@mellanox.com>

So far, there was possible only to register a single filter chain
pointer to block->chain[0]. However, when the blocks will get shareable,
we need to allow multiple filter chain pointers registration.

Signed-off-by: Jiri Pirko <j...@mellanox.com>
---
v3->v4:
- rebased on top of the current net-next
- added some extack strings
v2->v3:
- rebased on top of the current net-next
---
 include/net/pkt_cls.h     |   3 +
 include/net/sch_generic.h |   5 +-
 net/sched/cls_api.c       | 236 +++++++++++++++++++++++++++++++++++++++++-----
 3 files changed, 216 insertions(+), 28 deletions(-)

diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index 5cd3cf5..95c90da 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -29,6 +29,8 @@ struct tcf_block_ext_info {
        enum tcf_block_binder_type binder_type;
        tcf_chain_head_change_t *chain_head_change;
        void *chain_head_change_priv;
+       bool shareable;
+       u32 block_index;
 };
 
 struct tcf_block_cb;
@@ -50,6 +52,7 @@ void tcf_block_put_ext(struct tcf_block *block, struct Qdisc 
*q,
 
 static inline struct Qdisc *tcf_block_q(struct tcf_block *block)
 {
+       WARN_ON(block->refcnt != 1);
        return block->q;
 }
 
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index ac029d5..5cc4d71 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -275,8 +275,7 @@ typedef void tcf_chain_head_change_t(struct tcf_proto 
*tp_head, void *priv);
 
 struct tcf_chain {
        struct tcf_proto __rcu *filter_chain;
-       tcf_chain_head_change_t *chain_head_change;
-       void *chain_head_change_priv;
+       struct list_head filter_chain_list;
        struct list_head list;
        struct tcf_block *block;
        u32 index; /* chain index */
@@ -285,6 +284,8 @@ struct tcf_chain {
 
 struct tcf_block {
        struct list_head chain_list;
+       u32 index; /* block index for shared blocks */
+       unsigned int refcnt;
        struct net *net;
        struct Qdisc *q;
        struct list_head cb_list;
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 6708b69..2dd584a 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -24,6 +24,7 @@
 #include <linux/init.h>
 #include <linux/kmod.h>
 #include <linux/slab.h>
+#include <linux/idr.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/netlink.h>
@@ -179,6 +180,12 @@ static void tcf_proto_destroy(struct tcf_proto *tp)
        kfree_rcu(tp, rcu);
 }
 
+struct tcf_filter_chain_list_item {
+       struct list_head list;
+       tcf_chain_head_change_t *chain_head_change;
+       void *chain_head_change_priv;
+};
+
 static struct tcf_chain *tcf_chain_create(struct tcf_block *block,
                                          u32 chain_index)
 {
@@ -187,6 +194,7 @@ static struct tcf_chain *tcf_chain_create(struct tcf_block 
*block,
        chain = kzalloc(sizeof(*chain), GFP_KERNEL);
        if (!chain)
                return NULL;
+       INIT_LIST_HEAD(&chain->filter_chain_list);
        list_add_tail(&chain->list, &block->chain_list);
        chain->block = block;
        chain->index = chain_index;
@@ -194,12 +202,19 @@ static struct tcf_chain *tcf_chain_create(struct 
tcf_block *block,
        return chain;
 }
 
+static void tcf_chain_head_change_item(struct tcf_filter_chain_list_item *item,
+                                      struct tcf_proto *tp_head)
+{
+       if (item->chain_head_change)
+               item->chain_head_change(tp_head, item->chain_head_change_priv);
+}
 static void tcf_chain_head_change(struct tcf_chain *chain,
                                  struct tcf_proto *tp_head)
 {
-       if (chain->chain_head_change)
-               chain->chain_head_change(tp_head,
-                                        chain->chain_head_change_priv);
+       struct tcf_filter_chain_list_item *item;
+
+       list_for_each_entry(item, &chain->filter_chain_list, list)
+               tcf_chain_head_change_item(item, tp_head);
 }
 
 static void tcf_chain_flush(struct tcf_chain *chain)
@@ -280,17 +295,91 @@ static void tcf_block_offload_unbind(struct tcf_block 
*block, struct Qdisc *q,
        tcf_block_offload_cmd(block, q, ei, TC_BLOCK_UNBIND);
 }
 
-int tcf_block_get_ext(struct tcf_block **p_block, struct Qdisc *q,
-                     struct tcf_block_ext_info *ei,
-                     struct netlink_ext_ack *extack)
+static int
+tcf_chain_head_change_cb_add(struct tcf_chain *chain,
+                            struct tcf_block_ext_info *ei,
+                            struct netlink_ext_ack *extack)
 {
-       struct tcf_block *block = kzalloc(sizeof(*block), GFP_KERNEL);
+       struct tcf_filter_chain_list_item *item;
+
+       item = kmalloc(sizeof(*item), GFP_KERNEL);
+       if (!item) {
+               NL_SET_ERR_MSG(extack, "Memory allocation for head change 
callback item failed");
+               return -ENOMEM;
+       }
+       item->chain_head_change = ei->chain_head_change;
+       item->chain_head_change_priv = ei->chain_head_change_priv;
+       if (chain->filter_chain)
+               tcf_chain_head_change_item(item, chain->filter_chain);
+       list_add(&item->list, &chain->filter_chain_list);
+       return 0;
+}
+
+static void
+tcf_chain_head_change_cb_del(struct tcf_chain *chain,
+                            struct tcf_block_ext_info *ei)
+{
+       struct tcf_filter_chain_list_item *item;
+
+       list_for_each_entry(item, &chain->filter_chain_list, list) {
+               if ((!ei->chain_head_change && !ei->chain_head_change_priv) ||
+                   (item->chain_head_change == ei->chain_head_change &&
+                    item->chain_head_change_priv == 
ei->chain_head_change_priv)) {
+                       tcf_chain_head_change_item(item, NULL);
+                       list_del(&item->list);
+                       kfree(item);
+                       return;
+               }
+       }
+       WARN_ON(1);
+}
+
+struct tcf_net {
+       struct idr idr;
+};
+
+static unsigned int tcf_net_id;
+
+static int tcf_block_insert(struct tcf_block *block, struct net *net,
+                           u32 block_index, struct netlink_ext_ack *extack)
+{
+       struct tcf_net *tn = net_generic(net, tcf_net_id);
+       int idr_start;
+       int idr_end;
+       int index;
+
+       if (block_index >= INT_MAX) {
+               NL_SET_ERR_MSG(extack, "Invalid block index value (>= 
INT_MAX)");
+               return -EINVAL;
+       }
+       idr_start = block_index ? block_index : 1;
+       idr_end = block_index ? block_index + 1 : INT_MAX;
+
+       index = idr_alloc(&tn->idr, block, idr_start, idr_end, GFP_KERNEL);
+       if (index < 0)
+               return index;
+       block->index = index;
+       return 0;
+}
+
+static void tcf_block_remove(struct tcf_block *block, struct net *net)
+{
+       struct tcf_net *tn = net_generic(net, tcf_net_id);
+
+       idr_remove(&tn->idr, block->index);
+}
+
+static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q,
+                                         struct netlink_ext_ack *extack)
+{
+       struct tcf_block *block;
        struct tcf_chain *chain;
        int err;
 
+       block = kzalloc(sizeof(*block), GFP_KERNEL);
        if (!block) {
                NL_SET_ERR_MSG(extack, "Memory allocation for block failed");
-               return -ENOMEM;
+               return ERR_PTR(-ENOMEM);
        }
        INIT_LIST_HEAD(&block->chain_list);
        INIT_LIST_HEAD(&block->cb_list);
@@ -302,17 +391,75 @@ int tcf_block_get_ext(struct tcf_block **p_block, struct 
Qdisc *q,
                err = -ENOMEM;
                goto err_chain_create;
        }
-       WARN_ON(!ei->chain_head_change);
-       chain->chain_head_change = ei->chain_head_change;
-       chain->chain_head_change_priv = ei->chain_head_change_priv;
        block->net = qdisc_net(q);
+       block->refcnt = 1;
+       block->net = net;
        block->q = q;
+       return block;
+
+err_chain_create:
+       kfree(block);
+       return ERR_PTR(err);
+}
+
+static struct tcf_block *tcf_block_lookup(struct net *net, u32 block_index)
+{
+       struct tcf_net *tn = net_generic(net, tcf_net_id);
+
+       return idr_find(&tn->idr, block_index);
+}
+
+static struct tcf_chain *tcf_block_chain_zero(struct tcf_block *block)
+{
+       return list_first_entry(&block->chain_list, struct tcf_chain, list);
+}
+
+int tcf_block_get_ext(struct tcf_block **p_block, struct Qdisc *q,
+                     struct tcf_block_ext_info *ei,
+                     struct netlink_ext_ack *extack)
+{
+       struct net *net = qdisc_net(q);
+       struct tcf_block *block = NULL;
+       bool created = false;
+       int err;
+
+       if (ei->shareable) {
+               block = tcf_block_lookup(net, ei->block_index);
+               if (block)
+                       block->refcnt++;
+       }
+
+       if (!block) {
+               block = tcf_block_create(net, q, extack);
+               if (IS_ERR(block))
+                       return PTR_ERR(block);
+               created = true;
+               if (ei->shareable) {
+                       err = tcf_block_insert(block, net,
+                                              ei->block_index, extack);
+                       if (err)
+                               goto err_block_insert;
+               }
+       }
+
+       err = tcf_chain_head_change_cb_add(tcf_block_chain_zero(block),
+                                          ei, extack);
+       if (err)
+               goto err_chain_head_change_cb_add;
+
        tcf_block_offload_bind(block, q, ei);
        *p_block = block;
        return 0;
 
-err_chain_create:
-       kfree(block);
+err_chain_head_change_cb_add:
+       if (created) {
+               if (ei->shareable)
+                       tcf_block_remove(block, net);
+err_block_insert:
+               kfree(block);
+       } else {
+               block->refcnt--;
+       }
        return err;
 }
 EXPORT_SYMBOL(tcf_block_get_ext);
@@ -346,26 +493,35 @@ void tcf_block_put_ext(struct tcf_block *block, struct 
Qdisc *q,
 {
        struct tcf_chain *chain, *tmp;
 
-       /* Hold a refcnt for all chains, so that they don't disappear
-        * while we are iterating.
-        */
        if (!block)
                return;
-       list_for_each_entry(chain, &block->chain_list, list)
-               tcf_chain_hold(chain);
 
-       list_for_each_entry(chain, &block->chain_list, list)
-               tcf_chain_flush(chain);
+       tcf_chain_head_change_cb_del(tcf_block_chain_zero(block), ei);
+
+       if (--block->refcnt == 0) {
+               if (ei->shareable)
+                       tcf_block_remove(block, block->net);
+
+               /* Hold a refcnt for all chains, so that they don't disappear
+                * while we are iterating.
+                */
+               list_for_each_entry(chain, &block->chain_list, list)
+                       tcf_chain_hold(chain);
+
+               list_for_each_entry(chain, &block->chain_list, list)
+                       tcf_chain_flush(chain);
+       }
 
        tcf_block_offload_unbind(block, q, ei);
 
-       /* At this point, all the chains should have refcnt >= 1. */
-       list_for_each_entry_safe(chain, tmp, &block->chain_list, list)
-               tcf_chain_put(chain);
+       if (block->refcnt == 0) {
+               /* At this point, all the chains should have refcnt >= 1. */
+               list_for_each_entry_safe(chain, tmp, &block->chain_list, list)
+                       tcf_chain_put(chain);
 
-       /* Finally, put chain 0 and allow block to be freed. */
-       chain = list_first_entry(&block->chain_list, struct tcf_chain, list);
-       tcf_chain_put(chain);
+               /* Finally, put chain 0 and allow block to be freed. */
+               tcf_chain_put(tcf_block_chain_zero(block));
+       }
 }
 EXPORT_SYMBOL(tcf_block_put_ext);
 
@@ -1252,12 +1408,40 @@ int tc_setup_cb_call(struct tcf_block *block, struct 
tcf_exts *exts,
 }
 EXPORT_SYMBOL(tc_setup_cb_call);
 
+static __net_init int tcf_net_init(struct net *net)
+{
+       struct tcf_net *tn = net_generic(net, tcf_net_id);
+
+       idr_init(&tn->idr);
+       return 0;
+}
+
+static void __net_exit tcf_net_exit(struct net *net)
+{
+       struct tcf_net *tn = net_generic(net, tcf_net_id);
+
+       idr_destroy(&tn->idr);
+}
+
+static struct pernet_operations tcf_net_ops = {
+       .init = tcf_net_init,
+       .exit = tcf_net_exit,
+       .id   = &tcf_net_id,
+       .size = sizeof(struct tcf_net),
+};
+
 static int __init tc_filter_init(void)
 {
+       int err;
+
        tc_filter_wq = alloc_ordered_workqueue("tc_filter_workqueue", 0);
        if (!tc_filter_wq)
                return -ENOMEM;
 
+       err = register_pernet_subsys(&tcf_net_ops);
+       if (err)
+               return err;
+
        rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, 0);
        rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, 0);
        rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
-- 
2.9.5

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