netdev - Re: [RFC Patch net-next] net_sched: make classifying lockless on ingress

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1387583344.19078.475.camel@edumazet-glaptop2.roam.corp.google.com>
Date:	Fri, 20 Dec 2013 15:49:04 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Cong Wang <xiyou.wangcong@...il.com>
Cc:	netdev@...r.kernel.org, "David S. Miller" <davem@...emloft.net>,
	Jamal Hadi Salim <jhs@...atatu.com>,
	John Fastabend <john.r.fastabend@...el.com>
Subject: Re: [RFC Patch net-next] net_sched: make classifying lockless on
 ingress

On Fri, 2013-12-20 at 15:28 -0800, Cong Wang wrote:

> diff --git a/net/core/dev.c b/net/core/dev.c
> index c482fe8..7cc0d6a 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -3382,10 +3382,8 @@ static int ing_filter(struct sk_buff *skb, struct netdev_queue *rxq)
>  
>  	q = rxq->qdisc;
>  	if (q != &noop_qdisc) {
> -		spin_lock(qdisc_lock(q));
>  		if (likely(!test_bit(__QDISC_STATE_DEACTIVATED, &q->state)))
>  			result = qdisc_enqueue_root(skb, q);
> -		spin_unlock(qdisc_lock(q));
>  	}
>  

Well... That would be too easy.

Really, a lot more work would be needed.

Qdisc ->enqueue()/dequeue()/reset()/... all assume the qdisc lock is
held.

John Fastabend did some work on this area.



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html