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

[Wolfgang Walter]

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.

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