[PATCH net v3] net/sched: cls_api: Fix nooffloaddevcnt counter when indr block call success

[wenxu@ucloud.cn]

From: wenxu <wenxu@ucloud.cn>

A vxlan or gretap device offload through indr block methord. If the device
successfully bind with a real hw through indr block call, It also add
nooffloadcnt counter. This counter will lead the rule add failed in
fl_hw_replace_filter-->tc_setup_cb_call with skip_sw flags.

In the tc_setup_cb_call will check the nooffloaddevcnt and skip_sw flags
as following:
if (block->nooffloaddevcnt && err_stop)
        return -EOPNOTSUPP;

So with this patch, if the indr block call success, it will not modify
the nooffloaddevcnt counter.

Fixes: 7f76fa36754b ("net: sched: register callbacks for indirect tc block binds")
Signed-off-by: wenxu <wenxu@ucloud.cn>
---
v3: rebase to the net

 net/sched/cls_api.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 32577c2..c980127 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -607,11 +607,11 @@ static void tc_indr_block_get_and_ing_cmd(struct net_device *dev,
 	tc_indr_block_ing_cmd(dev, block, cb, cb_priv, command);
 }
 
-static void tc_indr_block_call(struct tcf_block *block,
-			       struct net_device *dev,
-			       struct tcf_block_ext_info *ei,
-			       enum flow_block_command command,
-			       struct netlink_ext_ack *extack)
+static int tc_indr_block_call(struct tcf_block *block,
+			      struct net_device *dev,
+			      struct tcf_block_ext_info *ei,
+			      enum flow_block_command command,
+			      struct netlink_ext_ack *extack)
 {
 	struct flow_block_offload bo = {
 		.command	= command,
@@ -621,10 +621,15 @@ static void tc_indr_block_call(struct tcf_block *block,
 		.block_shared	= tcf_block_shared(block),
 		.extack		= extack,
 	};
+
 	INIT_LIST_HEAD(&bo.cb_list);
 
 	flow_indr_block_call(dev, &bo, command);
-	tcf_block_setup(block, &bo);
+
+	if (list_empty(&bo.cb_list))
+		return -EOPNOTSUPP;
+
+	return tcf_block_setup(block, &bo);
 }
 
 static bool tcf_block_offload_in_use(struct tcf_block *block)
@@ -681,8 +686,6 @@ static int tcf_block_offload_bind(struct tcf_block *block, struct Qdisc *q,
 		goto no_offload_dev_inc;
 	if (err)
 		goto err_unlock;
-
-	tc_indr_block_call(block, dev, ei, FLOW_BLOCK_BIND, extack);
 	up_write(&block->cb_lock);
 	return 0;
 
@@ -691,9 +694,10 @@ static int tcf_block_offload_bind(struct tcf_block *block, struct Qdisc *q,
 		err = -EOPNOTSUPP;
 		goto err_unlock;
 	}
+	err = tc_indr_block_call(block, dev, ei, FLOW_BLOCK_BIND, extack);
+	if (err)
+		block->nooffloaddevcnt++;
 	err = 0;
-	block->nooffloaddevcnt++;
-	tc_indr_block_call(block, dev, ei, FLOW_BLOCK_BIND, extack);
 err_unlock:
 	up_write(&block->cb_lock);
 	return err;
@@ -706,8 +710,6 @@ static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q,
 	int err;
 
 	down_write(&block->cb_lock);
-	tc_indr_block_call(block, dev, ei, FLOW_BLOCK_UNBIND, NULL);
-
 	if (!dev->netdev_ops->ndo_setup_tc)
 		goto no_offload_dev_dec;
 	err = tcf_block_offload_cmd(block, dev, ei, FLOW_BLOCK_UNBIND, NULL);
@@ -717,7 +719,9 @@ static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q,
 	return;
 
 no_offload_dev_dec:
-	WARN_ON(block->nooffloaddevcnt-- == 0);
+	err = tc_indr_block_call(block, dev, ei, FLOW_BLOCK_UNBIND, NULL);
+	if (err)
+		WARN_ON(block->nooffloaddevcnt-- == 0);
 	up_write(&block->cb_lock);
 }
 
-- 
1.8.3.1