diff mbox series

[net-next,v3,03/16] net: sched: protect block->chain0 with block->lock

Message ID 20190204123301.4223-4-vladbu@mellanox.com
State Changes Requested
Delegated to: David Miller
Headers show
Series Refactor classifier API to work with chain/classifiers without rtnl lock | expand

Commit Message

Vlad Buslov Feb. 4, 2019, 12:32 p.m. UTC 
In order to remove dependency on rtnl lock, use block->lock to protect
chain0 struct from concurrent modification. Rearrange code in chain0
callback add and del functions to only access chain0 when block->lock is
held.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/cls_api.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

Comments

Jiri Pirko Feb. 4, 2019, 4:30 p.m. UTC | #1 
Mon, Feb 04, 2019 at 01:32:48PM CET, vladbu@mellanox.com wrote:
>In order to remove dependency on rtnl lock, use block->lock to protect
>chain0 struct from concurrent modification. Rearrange code in chain0
>callback add and del functions to only access chain0 when block->lock is
>held.
>
>Signed-off-by: Vlad Buslov <vladbu@mellanox.com>

Acked-by: Jiri Pirko <jiri@mellanox.com>
diff mbox series

Patch

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index a1bd1cd0e1ae..9db028f6ac86 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -236,8 +236,11 @@  static void tcf_chain0_head_change(struct tcf_chain *chain,
 
 	if (chain->index)
 		return;
+
+	mutex_lock(&block->lock);
 	list_for_each_entry(item, &block->chain0.filter_chain_list, list)
 		tcf_chain_head_change_item(item, tp_head);
+	mutex_unlock(&block->lock);
 }
 
 /* Returns true if block can be safely freed. */
@@ -748,8 +751,8 @@  tcf_chain0_head_change_cb_add(struct tcf_block *block,
 			      struct tcf_block_ext_info *ei,
 			      struct netlink_ext_ack *extack)
 {
-	struct tcf_chain *chain0 = block->chain0.chain;
 	struct tcf_filter_chain_list_item *item;
+	struct tcf_chain *chain0;
 
 	item = kmalloc(sizeof(*item), GFP_KERNEL);
 	if (!item) {
@@ -758,9 +761,14 @@  tcf_chain0_head_change_cb_add(struct tcf_block *block,
 	}
 	item->chain_head_change = ei->chain_head_change;
 	item->chain_head_change_priv = ei->chain_head_change_priv;
+
+	mutex_lock(&block->lock);
+	chain0 = block->chain0.chain;
 	if (chain0 && chain0->filter_chain)
 		tcf_chain_head_change_item(item, chain0->filter_chain);
 	list_add(&item->list, &block->chain0.filter_chain_list);
+	mutex_unlock(&block->lock);
+
 	return 0;
 }
 
@@ -768,20 +776,23 @@  static void
 tcf_chain0_head_change_cb_del(struct tcf_block *block,
 			      struct tcf_block_ext_info *ei)
 {
-	struct tcf_chain *chain0 = block->chain0.chain;
 	struct tcf_filter_chain_list_item *item;
 
+	mutex_lock(&block->lock);
 	list_for_each_entry(item, &block->chain0.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)) {
-			if (chain0)
+			if (block->chain0.chain)
 				tcf_chain_head_change_item(item, NULL);
 			list_del(&item->list);
+			mutex_unlock(&block->lock);
+
 			kfree(item);
 			return;
 		}
 	}
+	mutex_unlock(&block->lock);
 	WARN_ON(1);
 }