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From: Arnd Bergmann <arnd@arndb.de>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: gregkh <gregkh@linuxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCHES] tty ioctls cleanups, compat and not only
Date: Thu, 13 Sep 2018 22:56:48 +0200	[thread overview]
Message-ID: <CAK8P3a3LD58jnwP38OpnEWHMzAAfrqtfjHamWVU5PwaKoWyKjg@mail.gmail.com> (raw)
In-Reply-To: <20180913203145.GU19965@ZenIV.linux.org.uk>

On Thu, Sep 13, 2018 at 10:31 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> On Thu, Sep 13, 2018 at 01:19:42PM +0200, Arnd Bergmann wrote:
> > On Thu, Sep 13, 2018 at 4:31 AM Al Viro <viro@zeniv.linux.org.uk> wrote:
> > * TIOCSERGWILD/TIOCSERSWILD are obsolete and never do
> >    anything useful, but the return code is inconsistent: ENOTTY
> >    in compat mode vs 0 in uart_ioctl, plus a printk for amiserial.
> >    If we want to keep it around rather than deleting it completely,
> >    it should be marked as compatible.
>
> Yes.  Not sure if we want to - the only user is setserial(8), with
>        -W     Do wild interrupt initialization and exit.  This  option  is  no
>               longer relevant in Linux kernels after version 2.1.
>
> What's more, rc.serial does *not* use it since 2.15 and even in 2.14 it wouldn't
> have failed the boot - just whine (truthfully) "Cannot scan for wild interrupts"
> on stderr and continue with the rest of the script.  The same goes at least as
> far back as setserial-2.02.  That's what MCC had; if you want to check something
> earlier, you'll probably have to ask tytso, but I very much doubt that anything
> of that vintage will work with the current kernels *or* that anyone cared to
> abort the script in question on setserial -W /dev/cua0 failing to start with.
>
> So I'd seriously suggest removing those altogether.  I mean, sure, we can carry
> explicit "obsolete, quietly return 0 on those" indefinitely, but that really feels
> over the top.  Time to bury the body, unless somebody objects...

Sounds good to me.

> > * PPPIOCGCHAN/PPPIOCGUNIT are implemented by multiple
> >    ldisc variants, marking them as compatible would save us from
> >    implementing a comp_ioctl method for each one separately.
> >    These are also used on some things that are not ttys though,
> >    so we can't remove them from fs/compat_ioctl.c yet.
>
> Worse - there's ipwireless, which implements it in tty_operations ->ioctl().

Yes, I saw that too, but couldn't figure out exactly what ipwireless
does. I suppose it is some serial port driver that comes with a
hardcoded ppp implementation instead of a switchable ldisc?

> > * SIOCGIFNAME, SIOCGIFENCAP, SIOCSIFENCAP,
> >   SIOCSIFHWADDR, SIOCSKEEPALIVE, SIOCGKEEPALIVE,
> >   SIOCSOUTFILL,  and SIOCGOUTFILL  are in the tty_ioctl
> >   functions for multiple protocol handlers, comparable to
> >   the PPP ones.
>
> Very definitely shared with sockets, and I prefer to handle the tty-side cases
> in ldisc ->compat_ioctl().

Fair enough.

        Arnd

  reply	other threads:[~2018-09-13 20:57 UTC|newest]

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-13  2:31 [PATCHES] tty ioctls cleanups, compat and not only Al Viro
2018-09-13  2:40 ` [PATCH 01/50] presence of RS485 ioctls has been unconditional since 2014 Al Viro
2018-09-13  2:40   ` [PATCH 02/50] move compat handling of tty ioctls to tty_compat_ioctl() Al Viro
2018-09-14 15:15     ` Arnd Bergmann
2018-09-14 18:16       ` gregkh
2018-09-14 19:38         ` Arnd Bergmann
2018-09-15 18:51           ` gregkh
2018-09-13  2:40   ` [PATCH 03/50] tty_ioctl(): drop FIONBIO handling Al Viro
2018-09-13  2:40   ` [PATCH 04/50] mos7720: bury dead TIOCM... in ->ioctl() Al Viro
2018-09-14 13:31     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 05/50] tty_ioctl(): start taking TIOC[SG]SERIAL into separate methods Al Viro
2018-09-14 13:22     ` Johan Hovold
2018-09-14 15:18       ` Al Viro
2018-09-14 16:23         ` Johan Hovold
2018-09-13  2:40   ` [PATCH 06/50] simserial: switch to ->[sg]et_serial() Al Viro
2018-09-13  2:40   ` [PATCH 07/50] fwserial: " Al Viro
2018-09-13  2:40   ` [PATCH 08/50] greybus/uart: " Al Viro
2018-09-14 13:31     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 09/50] amiserial: " Al Viro
2018-09-13 10:33     ` Greg Kroah-Hartman
2018-10-11 17:58     ` Geert Uytterhoeven
2018-10-13  5:36       ` Al Viro
2018-09-13  2:40   ` [PATCH 10/50] cyclades: " Al Viro
2018-09-13  2:40   ` [PATCH 11/50] ipwireless: " Al Viro
2018-09-14 12:00     ` David Sterba
2018-09-13  2:40   ` [PATCH 12/50] isicom: " Al Viro
2018-09-13  2:40   ` [PATCH 13/50] moxa: " Al Viro
2018-09-13  2:40   ` [PATCH 14/50] mxser: " Al Viro
2018-09-13  2:40   ` [PATCH 15/50] serial_core: " Al Viro
2018-09-13  2:40   ` [PATCH 16/50] rfcomm: get rid of mentioning TIOC[SG]SERIAL Al Viro
2018-09-13  2:40   ` [PATCH 17/50] usb-serial: begin switching to ->[sg]et_serial() Al Viro
2018-09-14 13:39     ` Johan Hovold
2018-09-14 15:23       ` Al Viro
2018-09-14 15:26         ` Johan Hovold
2018-09-13  2:40   ` [PATCH 18/50] cdc-acm: switch " Al Viro
2018-09-13  2:40   ` [PATCH 19/50] ark3116: switch to ->get_serial() Al Viro
2018-09-14 13:41     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 20/50] f81232: " Al Viro
2018-09-14 13:42     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 21/50] f81534: " Al Viro
2018-09-14 13:43     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 22/50] fdti_sio: switch to ->[sg]et_serial() Al Viro
2018-09-14 13:47     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 23/50] io_edgeport: switch to ->get_serial() Al Viro
2018-09-14 13:58     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 24/50] io_ti: " Al Viro
2018-09-14 13:59     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 25/50] mos7720: " Al Viro
2018-09-14 14:02     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 26/50] mos7840: " Al Viro
2018-09-14 14:07     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 27/50] opticon: " Al Viro
2018-09-14 14:08     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 28/50] pl2303: " Al Viro
2018-09-14 14:08     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 29/50] quatech2: " Al Viro
2018-09-14 14:09     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 30/50] ssu100: " Al Viro
2018-09-14 14:10     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 31/50] ti_usb_3410_5052: switch to ->[sg]et_serial() Al Viro
2018-09-14 14:12     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 32/50] whiteheat: switch to ->get_serial() Al Viro
2018-09-14 14:15     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 33/50] usb_wwan: switch to ->[sg]et_serial() Al Viro
2018-09-14 14:18     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 34/50] complete ->[sg]et_serial() switchover Al Viro
2018-09-14 14:20     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 35/50] synclink: reduce pointless checks in ->ioctl() Al Viro
2018-09-13  2:40   ` [PATCH 36/50] take compat TIOC[SG]SERIAL treatment into tty_compat_ioctl() Al Viro
2018-09-13  2:40   ` [PATCH 37/50] kill capinc_tty_ioctl() Al Viro
2018-09-13  2:40   ` [PATCH 38/50] isdn_tty: TCSBRK{,P} won't reach ->ioctl() Al Viro
2018-09-13  2:40   ` [PATCH 39/50] dgnc: TIOCM... " Al Viro
2018-09-13  2:40   ` [PATCH 40/50] kill the rest of tty COMPAT_IOCTL() entries Al Viro
2018-09-13 10:55     ` Arnd Bergmann
2018-09-13  2:40   ` [PATCH 41/50] dgnc: break-related ioctls won't reach ->ioctl() Al Viro
2018-09-13 11:59     ` Greg Kroah-Hartman
2018-09-13  2:40   ` [PATCH 42/50] remove fallback to drivers for TIOCGICOUNT Al Viro
2018-09-14 14:23     ` Johan Hovold
2018-09-13  2:40   ` [PATCH 43/50] dgnc: leave TIOC[GS]SOFTCAR to ldisc Al Viro
2018-09-13  2:40   ` [PATCH 44/50] dgnc: don't bother with (empty) stub for TCXONC Al Viro
2018-09-13  2:40   ` [PATCH 45/50] gigaset: don't try to printk userland buffer contents Al Viro
2018-09-13  2:40   ` [PATCH 46/50] vt_compat_ioctl(): clean up, use compat_ptr() properly Al Viro
2018-09-13 10:10     ` Arnd Bergmann
2018-09-13  2:40   ` [PATCH 47/50] gigaset: add ->compat_ioctl() Al Viro
2018-09-13  2:40   ` [PATCH 48/50] compat_ioctl - kill keyboard ioctl handling Al Viro
2018-09-13  2:40   ` [PATCH 49/50] pty: fix compat ioctls Al Viro
2018-09-13  2:40   ` [PATCH 50/50] synclink_gt(): fix compat_ioctl() Al Viro
2018-09-13 11:19 ` [PATCHES] tty ioctls cleanups, compat and not only Arnd Bergmann
2018-09-13 20:31   ` Al Viro
2018-09-13 20:56     ` Arnd Bergmann [this message]
2018-09-14  2:27       ` Al Viro
2018-09-14  8:21         ` Arnd Bergmann
2018-09-14 15:10           ` Al Viro
2018-09-14 15:33             ` Arnd Bergmann
2018-09-13 11:59 ` Greg Kroah-Hartman

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