net: sched: don't set q pointer for shared blocks

It is pointless to set block->q for block which are shared among
multiple qdiscs. So remove the assignment in that case. Do a bit of code
reshuffle to make block->index initialized at that point so we can use
tcf_block_shared() helper.

Reported-by: Cong Wang <xiyou.wangcong@gmail.com>
Fixes: 4861738775d7 ("net: sched: introduce shared filter blocks infrastructure")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 2bc1bc2..a7dc727 100644 (file)
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -376,17 +376,12 @@ struct tcf_net {
 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 netlink_ext_ack *extack)
 {
        struct tcf_net *tn = net_generic(net, tcf_net_id);
-       int err;
 
-       err = idr_alloc_u32(&tn->idr, block, &block_index, block_index,
-                           GFP_KERNEL);
-       if (err)
-               return err;
-       block->index = block_index;
-       return 0;
+       return idr_alloc_u32(&tn->idr, block, &block->index, block->index,
+                            GFP_KERNEL);
 }
 
 static void tcf_block_remove(struct tcf_block *block, struct net *net)
@@ -397,6 +392,7 @@ static void tcf_block_remove(struct tcf_block *block, struct net *net)
 }
 
 static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q,
+                                         u32 block_index,
                                          struct netlink_ext_ack *extack)
 {
        struct tcf_block *block;
@@ -419,10 +415,13 @@ static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q,
                err = -ENOMEM;
                goto err_chain_create;
        }
-       block->net = qdisc_net(q);
        block->refcnt = 1;
        block->net = net;
-       block->q = q;
+       block->index = block_index;
+
+       /* Don't store q pointer for blocks which are shared */
+       if (!tcf_block_shared(block))
+               block->q = q;
        return block;
 
 err_chain_create:
@@ -518,13 +517,12 @@ int tcf_block_get_ext(struct tcf_block **p_block, struct Qdisc *q,
        }
 
        if (!block) {
-               block = tcf_block_create(net, q, extack);
+               block = tcf_block_create(net, q, ei->block_index, extack);
                if (IS_ERR(block))
                        return PTR_ERR(block);
                created = true;
-               if (ei->block_index) {
-                       err = tcf_block_insert(block, net,
-                                              ei->block_index, extack);
+               if (tcf_block_shared(block)) {
+                       err = tcf_block_insert(block, net, extack);
                        if (err)
                                goto err_block_insert;
                }