Date: Thu, 3 Dec 2009 12:24:58 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Rodolfo Giometti <giometti@enneenne.com>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
       David Woodhouse <dwmw2@infradead.org>, Dave Jones <davej@redhat.com>,
       Sam Ravnborg <sam@ravnborg.org>, Greg KH <greg@kroah.com>,
       Randy Dunlap <randy.dunlap@oracle.com>,
       Kay Sievers <kay.sievers@vrfy.org>, "H. Peter Anvin" <hpa@zytor.com>,
       Ingo Molnar <mingo@elte.hu>, Michael Kerrisk <mtk.manpages@gmail.com>,
       Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH 06/11] pps: serial clients support.
Message-ID: <20091203122458.16bb57d2@lxorguk.ukuu.org.uk>
In-Reply-To: <20091203120523.GE12943@gundam.enneenne.com>
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> > void n_tty_init_ops(struct tty_ldisc_ops *ops)
> > {
> > 	*ops = tty_ldisc_N_TTY;
> > 	ops->owner = NULL:
> > 	ops->refcount = ops->flags = 0;
> > }
> > EXPORT_SYMBOL_GPL(n_tty_inherit_ops);
> 
> The problem is that I have to do some operations into ldisc's open and
> close methods (see linux/drivers/pps/clients/pps-ldisc.c).
> 
> By using your solution I inherit such methods but I cannot modify
> their behaviour in a manner suitable for register/deregister PPS
> support at runtime.

You can

	n_tty_init_ops(&my_ops);
	my_ops.num = whatever;
	old_open = my_ops.open;
	my_ops.open = pps_ntty_open;

etc

While not as pretty in C as C++ it works fine.
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