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net: sched: protect block->chain0 with block->lock

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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>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vlad Buslov
2019-02-11 10:55:35 +02:00
committed by David S. Miller
parent 2cbfab07c6
commit 165f01354c
1 changed files with 14 additions and 3 deletions
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17
net/sched/cls_api.c
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@ -244,8 +244,11 @@ 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. */
@ -756,8 +759,8 @@ 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) {
@ -766,9 +769,14 @@ 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;
}
@ -776,20 +784,23 @@ 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);
}