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Message-ID: <7418fe470510190455x3bb746cax365092504e77ba3c@mail.gmail.com>
Date: Wed, 19 Oct 2005 13:55:35 +0200
From: Rabih ElMasri <rabih.elmasri@infineon.com>
To: lkml <linux-kernel@vger.kernel.org>
Subject: tty line discipline
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hi,

I am trying to assign a new line discipline to ttyS0 from within the
kernel-space. During the initialization of my module I do the
following:

fp=filp_open(dev,O_RDWR | O_NOCTTY,0);
tty=fp->private_data;  //the tty_struct

then I initialize the fields of the new line discipline (ldisc). and
assign it to the tty_struct:

tty->ldisc=ldisc;

It works fine the first time I insert the module, but gets problems
with tty->count if I insert it again.

I tried to call the tty_ioctl function of tty_io.c (with flag
TIOCSETD) using the corresponding field in the file structure
(fp->f_op->ioctl(..)), but it seems to expect a call from user-space,
and returns -EFAULT due to the get_user macro.

I would really appreciate it if someone can tell me how to deal with
this problem.

Regards,
Rabih