Re: [patch] sunrpc: make closing of old temporary sockets work (was: problems with lockd in 2.6.22.6)

From: Wolfgang Walter
Date: Fri Sep 14 2007 - 05:12:48 EST


Am Mittwoch, 12. September 2007 21:55 schrieb J. Bruce Fields:
> On Wed, Sep 12, 2007 at 09:40:57PM +0200, Wolfgang Walter wrote:
> > On Wednesday 12 September 2007, J. Bruce Fields wrote:
> > > On Wed, Sep 12, 2007 at 04:14:06PM +0200, Neil Brown wrote:
> > > > So it is in 2.6.21 and later and should probably go to .stable for
> > > > .21 and .22.
> > > >
> > > > Bruce: for you :-)
> > >
> > > OK, thanks! But, (as is alas often the case) I'm still confused:
> > > > if (!test_and_set_bit(SK_OLD, &svsk->sk_flags))
> > > > continue;
> > > > - if (atomic_read(&svsk->sk_inuse) || test_bit(SK_BUSY,
> > > > &svsk->sk_flags)) + if (atomic_read(&svsk->sk_inuse) > 1
> > > > + || test_bit(SK_BUSY, &svsk->sk_flags))
> > > > continue;
> > > > atomic_inc(&svsk->sk_inuse);
> > > > list_move(le, &to_be_aged);
> > >
> > > What is it that ensures svsk->sk_inuse isn't incremented or SK_BUSY set
> > > after that test? Not all the code that does either of those is under
> > > the same serv->sv_lock lock that this code is.
> >
> > This should not matter - SK_CLOSED may be set at any time.
> >
> > svc_age_temp_sockets only detaches the socket, sets SK_CLOSED and then
> > enqueues it. If SK_BUSY is set its already enqueued and svc_sock_enqueue
> > ensures that it is not enqueued twice.
>
> Oh, got it. And the list manipulation is safe thanks to sv_lock. Neat,
> thanks. Can you verify that this solves your problem?

Patch works fine here.

Regards,
--
Wolfgang Walter
Studentenwerk München
Anstalt des öffentlichen Rechts
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