From: Tejun Heo <tj@kernel.org>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Amit Shah <amit.shah@redhat.com>,
netdev@vger.kernel.org,
virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH RFC] virtio_net: fix refill related races
Date: Wed, 14 Dec 2011 15:54:12 -0800 [thread overview]
Message-ID: <20111214235412.GA29835@google.com> (raw)
In-Reply-To: <87iplltd0g.fsf@rustcorp.com.au>
Hello, Rusty.
On Tue, Dec 13, 2011 at 01:05:11PM +1030, Rusty Russell wrote:
> Both places where we call:
>
> cancel_delayed_work_sync(&vi->refill);
>
> Do not actually guarantee that vi->refill isn't running, because it
> can requeue itself. A 'bool no_more_refill' field seems like the
> simplest fix for this, but I don't think it's sufficient.
>
> Tejun, is this correct? What's the correct way to synchronously stop a
> delayed_work which can "schedule_delayed_work(&vi->refill, HZ/2);" on
> itself?
cancel_delayed_work_sync() itself should be good enough. It first
steals the pending state and then waits for it to finish if in-flight.
Queueing itself afterwards becomes noop.
Thanks.
--
tejun
next prev parent reply other threads:[~2011-12-14 23:54 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-07 15:21 [PATCH RFC] virtio_net: fix refill related races Michael S. Tsirkin
2011-12-08 4:37 ` Rusty Russell
2011-12-11 14:44 ` Michael S. Tsirkin
2011-12-11 22:55 ` Rusty Russell
2011-12-12 11:54 ` Michael S. Tsirkin
2011-12-13 2:35 ` Rusty Russell
2011-12-14 23:54 ` Tejun Heo [this message]
2011-12-20 19:09 ` Michael S. Tsirkin
2011-12-20 19:09 ` Tejun Heo
2011-12-20 19:30 ` Michael S. Tsirkin
2011-12-20 19:31 ` Tejun Heo
2011-12-20 19:45 ` Michael S. Tsirkin
2011-12-20 23:43 ` Rusty Russell
2011-12-21 9:06 ` Michael S. Tsirkin
2011-12-22 3:53 ` Rusty Russell
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