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Date: Mon, 14 Nov 2011 17:49:16 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Ilya Zykov <ilya@ilyx.ru>
Cc: Alan Cox <alan@linux.intel.com>, Greg Kroah-Hartman <gregkh@suse.de>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] TTY: tty flip buffer with synchronous line disciplines.
Message-ID: <20111114174916.648c2952@lxorguk.ukuu.org.uk>
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On Mon, 14 Nov 2011 21:41:36 +0400
Ilya Zykov <ilya@ilyx.ru> wrote:

> For use flip buffer with synchronous line disciplines(n_hdlc, ppp_synctty).

If you are doing synchronous protocols then they shouldn't be going via
the tty loopback in the first place. Why can't you use tuntap and the
like for synchronous protocols ? Stuffing them through the tty layer is a
bad hack anyway and not one we should encourage further.

> +	if ((b = tty->buf.tail) != NULL  && !tty->pty_sync)
>  		left = b->size - b->used;

What stops tty->pty_sync changing under the line discipline btw ?

Alan