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From: "David S. Miller" <davem@redhat.com>
To: Patrick McHardy <kaber@trash.net>
Cc: netdev@oss.sgi.com
Subject: Re: [PATCH 2.6 1/5]: Fix locking in __qdisc_destroy rcu-callback
Date: Wed, 4 Aug 2004 09:33:28 -0700	[thread overview]
Message-ID: <20040804093328.4ee56d30.davem@redhat.com> (raw)
In-Reply-To: <410FAD44.7020503@trash.net>

On Tue, 03 Aug 2004 17:20:36 +0200
Patrick McHardy <kaber@trash.net> wrote:

> The __qdisc_destroy rcu-callback doesn't do any locking when calling
> ops->reset and ops->destroy. qdisc_destroy is often called from both
> of these functions and it changes dev->qdisc_list. This patch adds proper
> locking to __qdisc_destroy. Unfortunately when using qdisc_tree_lock in
> process context we now also need to disable local bh's to avoid beeing
> interrupted by the rcu-callback. I'm not sure if RCU callback can be
> scheduled while the kernel is running in process context, so this may
> be unneccessary.

RCU callbacks run via tasklets, and thus in softirq context,
thus your locking changes to _bh() are indeed necessary.

I will apply this patch, thanks Patrick.

  reply	other threads:[~2004-08-04 16:33 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-08-03 15:20 [PATCH 2.6 1/5]: Fix locking in __qdisc_destroy rcu-callback Patrick McHardy
2004-08-04 16:33 ` David S. Miller [this message]
2004-08-04 19:53   ` Patrick McHardy

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