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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Jason Wessel <jason.wessel@windriver.com>
Cc: kgdb-bugreport@lists.sourceforge.net,
	linux-kernel@vger.kernel.org,
	Jason Wessel <jason.wessel@windriver.com>
Subject: Re: [PATCH 5/7] kgdboc, tty: use tty open to start low level drivers
Date: Tue, 21 Oct 2008 23:47:28 +0100	[thread overview]
Message-ID: <20081021234728.6853beee@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <1224616493-23237-6-git-send-email-jason.wessel@windriver.com>

On Tue, 21 Oct 2008 14:14:51 -0500
Jason Wessel <jason.wessel@windriver.com> wrote:

> This patch adds two new hooks to the tty layer in tty_io.c to allow

Gak

> A few minor changes were needed in tty_io.c to deal with the fact that
> the inode and fpath.dentry were NULL with the generic flip structure.

Gak and more gak

> +		tty = tty_driver_lookup_tty(driver, NULL, tty_line);
> +		if (!tty) {
> +			tty = tty_init_dev(driver, tty_line, 0);
> +			inc_tty = 0;
> +		}
> +		(*filp)->private_data = tty;
> +		ret = tty->ops->open(tty, *filp);

Digging deep into tty innards (some of which btw are going to change)

> +		unlock_kernel();
> +	} else {
> +		tty = tty_driver_lookup_tty(driver, NULL, tty_line);
> +		if (!tty) {
> +			tty = tty_init_dev(driver, tty_line, 0);
> +			inc_tty = 0;
> +		}
> +		(*filp)->private_data = tty;
> +		ret = tty->ops->open(tty, *filp);

and with the error paths wrong


This is to put it bluntly just horrible.

Really kgdb, console and other boot processes need an abstraction for tty
device ports at the device (not ldisc) level and until that work is done
there is no acceptable way to sort this out. Merging gunk like this will
simply make the existing mess worse and provide more crap that will make
it harder to fix properly.

All this stuff needs revisiting when every tty device side object in the
kernel contains a struct tty_port, until then it's a nasty (perhaps
neccessary for the moment) hack that belongs out of tree.

Alan

  parent reply	other threads:[~2008-10-21 22:47 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-21 19:14 kgdb 2.6.28 merge plans Jason Wessel
2008-10-21 19:14 ` [PATCH 1/7] kgdb: Add the ability to schedule a breakpoint via a tasklet Jason Wessel
2008-10-21 19:14   ` [PATCH 2/7] tty: Fix sparse static warning for tty_driver_lookup_tty Jason Wessel
2008-10-21 19:14     ` [PATCH 3/7] kgdboc, tty: Add the rx polling call back capability Jason Wessel
2008-10-21 19:14       ` [PATCH 4/7] kgdboc, 8250: Add the rx polling hook to 8250 driver Jason Wessel
2008-10-21 19:14         ` [PATCH 5/7] kgdboc, tty: use tty open to start low level drivers Jason Wessel
2008-10-21 19:14           ` [PATCH 6/7] kgdb: kgdboc console poll hooks for serial_txx9 uart Jason Wessel
2008-10-21 19:14             ` [PATCH 7/7] kgdb: Make mem access function weak in kgdb.c andkgdb.h Jason Wessel
2008-10-21 21:49           ` [PATCH 5/7] kgdboc, tty: use tty open to start low level drivers Jason Wessel
2008-10-21 22:47           ` Alan Cox [this message]
2008-10-22  1:54             ` Jason Wessel
2008-10-21 22:49 ` kgdb 2.6.28 merge plans Alan Cox
2008-10-22  2:09   ` Jason Wessel
2008-10-22  8:34     ` Alan Cox
2008-10-22 10:07       ` Jason Wessel
2008-10-22 12:25         ` Alan Cox

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