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From: Roman Mashak <mrv@mojatatu•com>
To: Cong Wang <xiyou.wangcong@gmail•com>
Cc: netdev@vger•kernel.org, Lucas Bates <lucasb@mojatatu•com>,
	Jamal Hadi Salim <jhs@mojatatu•com>,
	Jiri Pirko <jiri@resnulli•us>
Subject: Re: [Patch net 05/13] cls_cgroup: use tcf_exts_get_net() before call_rcu()
Date: Thu, 09 Nov 2017 17:31:10 -0500	[thread overview]
Message-ID: <857euzjd8x.fsf@mojatatu.com> (raw)
In-Reply-To: <20171106214730.24421-6-xiyou.wangcong@gmail.com> (Cong Wang's message of "Mon, 6 Nov 2017 13:47:22 -0800")

Cong Wang <xiyou.wangcong@gmail•com> writes:


[...]

>  static void cls_cgroup_destroy_work(struct work_struct *work)
>  {
>  	struct cls_cgroup_head *head = container_of(work,
>  						    struct cls_cgroup_head,
>  						    work);
>  	rtnl_lock();
> -	tcf_exts_destroy(&head->exts);
> -	tcf_em_tree_destroy(&head->ematches);
> -	kfree(head);
> +	__cls_cgroup_destroy(head);
>  	rtnl_unlock();
>  }
>  
> @@ -124,8 +130,10 @@ static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
>  		goto errout;
>  
>  	rcu_assign_pointer(tp->root, new);
> -	if (head)
> +	if (head) {
> +		tcf_exts_get_net(&head->exts);
>  		call_rcu(&head->rcu, cls_cgroup_destroy_rcu);

In this case why do you not need to care about success/failure of
tcf_exts_get_net() ?

> +	}
>  	return 0;
>  errout:
>  	tcf_exts_destroy(&new->exts);
> @@ -138,8 +146,12 @@ static void cls_cgroup_destroy(struct tcf_proto *tp)
>  	struct cls_cgroup_head *head = rtnl_dereference(tp->root);
>  
>  	/* Head can still be NULL due to cls_cgroup_init(). */
> -	if (head)
> -		call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
> +	if (head) {
> +		if (tcf_exts_get_net(&head->exts))
> +			call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
> +		else
> +			__cls_cgroup_destroy(head);
> +	}
>  }
>  
>  static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last)

  reply	other threads:[~2017-11-09 22:31 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-06 21:47 [Patch net 00/13] net_sched: close the race between call_rcu() and cleanup_net() Cong Wang
2017-11-06 21:47 ` [Patch net 01/13] Revert "net_sched: hold netns refcnt for each action" Cong Wang
2017-11-06 21:47 ` [Patch net 02/13] net_sched: introduce tcf_exts_get_net() and tcf_exts_put_net() Cong Wang
2017-11-06 21:47 ` [Patch net 03/13] cls_basic: use tcf_exts_get_net() before call_rcu() Cong Wang
2017-11-06 21:47 ` [Patch net 04/13] cls_bpf: " Cong Wang
2017-11-06 21:47 ` [Patch net 05/13] cls_cgroup: " Cong Wang
2017-11-09 22:31   ` Roman Mashak [this message]
2017-11-09 23:52     ` Cong Wang
2017-11-06 21:47 ` [Patch net 06/13] cls_flow: " Cong Wang
2017-11-06 21:47 ` [Patch net 07/13] cls_flower: " Cong Wang
2017-11-06 21:47 ` [Patch net 08/13] cls_fw: " Cong Wang
2017-11-06 21:47 ` [Patch net 09/13] cls_matchall: " Cong Wang
2017-11-06 21:47 ` [Patch net 10/13] cls_route: " Cong Wang
2017-11-06 21:47 ` [Patch net 11/13] cls_rsvp: " Cong Wang
2017-11-06 21:47 ` [Patch net 12/13] cls_tcindex: " Cong Wang
2017-11-06 21:47 ` [Patch net 13/13] cls_u32: " Cong Wang
2017-11-09  2:26 ` [Patch net 00/13] net_sched: close the race between call_rcu() and cleanup_net() David Miller
2017-11-09  2:32   ` Cong Wang

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