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List:       ipfilter
Subject:    Re: qif linklist
From:       Biswajit Tripathy <tbiswajit () sbcglobal ! net>
Date:       2003-08-20 8:49:35
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Hi Daren

--- darrenr@reed.wattle.id.au wrote:
> > Hi,
> > 
> >  As I did not get any response to my last mail re
> > qif link list (attached below), let me try my luck
> > again by giving a little background :-)
> > 
> > Currently, on HP-UX, the PFIL module uses autopush
> > to push itself over DLPI. This pushes PFIL into
> > any process that does a large number of open() to
> > /dev/dlpi, making the qif linklist very large.
> > I have had a system panic as it takes a long time
> > to execute the "for" loop under such circumstance
> > and the "spinlock is held too long". So I'm trying
> > to find a better "for" loop that does things
> > quicker.
> 
> I think the correct solution here would be to not
> create or push the pfil module in this situation.

 You are right. I'm trying to have a modified
 "ifconfig" on HP-UX that would accept an option 
 to push PFIL in while bringing up the interface.
 But the above problem can still show up when a large
 number of interfaces are created using VLAN (is that
 correct?).


> > > 	MUTEX_ENTER(&qif_mutex);
> > > 	qif->qf_q = q;
> > > 	qif->qf_oq = OTHERQ(q);
> > > 	i = 0;
> > > 	for (qf = qif_head; qf; qf = qf->qf_next)
> > > 		if (i == qf->qf_num) {
> > > 			i++;
> > > 			qf = qif_head;
> > > 		}
> 
> An alternative might be to derive qf_num from the
> value of qif rather than searching for a value.
> 
> Something like:
> 	i = (int)((intptr_t)qif & 0xffffffff);
> 	sprintf(qif->qf_name, sizeof(qif->qf_name),
> "QIF%x", i);

 I'm sorry I don't really get this part. Are you
 suggesting that I remove the entire for loop and
 put in the above two lines? How would qif & ffffffff
 give the value of i? Am I missing something
 obvious here (it's going to be 2.00AM and I think
 I need some sleep :-)) ?

- Biswajit

> 
> Darren

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