From: Russell King <rmk+lkml@arm.linux.org.uk>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
Pekka J Enberg <penberg@cs.Helsinki.FI>,
Ulrich Drepper <drepper@gmail.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
akpm@osdl.org, viro@zeniv.linux.org.uk, tytso@mit.edu,
tigran@veritas.com
Subject: Re: O_CAREFUL flag to disable open() side effects
Date: Thu, 27 Jul 2006 18:43:07 +0100 [thread overview]
Message-ID: <20060727174307.GC5178@flint.arm.linux.org.uk> (raw)
In-Reply-To: <44C8F8E3.1070306@zytor.com>
On Thu, Jul 27, 2006 at 10:33:23AM -0700, H. Peter Anvin wrote:
> Dumb thought: would it make sense to add an O_CAREFUL flag to open(), to
> disable side effects? It seems that a number of devices have this issue
> and one have to jump through weird hoops to configure them. Obviously,
> a file descriptor obtained with O_CAREFUL may not be fully functional,
> at the device driver's option.
>
> For a conventional file, directory, or block device O_CAREFUL is a
> no-op.
What about door locking on block devices? That might be an undesirable
side effect in some circumstances, so you might not want it to be a no-op
on blockdevs.
> For ttys it would typically behave similar to O_NONBLOCK
> followed immediately by a fcntl to clear the nonblock flag.
What about, eg, raising DTR and RTS ? You'd want to avoid raising
those if you're not actually going to be using the port.
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 Serial core
next prev parent reply other threads:[~2006-07-27 17:43 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-27 14:25 [RFC/PATCH] revoke/frevoke system calls V2 Pekka J Enberg
2006-07-27 15:07 ` Alan Cox
2006-07-27 15:33 ` Pekka Enberg
2006-07-27 16:09 ` Alan Cox
2006-07-27 16:01 ` Pekka J Enberg
2006-07-27 16:30 ` Alan Cox
2006-07-27 17:07 ` Pekka J Enberg
2006-07-27 18:27 ` Pekka Enberg
2006-07-27 16:41 ` Ulrich Drepper
2006-07-27 17:05 ` Pekka J Enberg
2006-07-27 17:13 ` Ulrich Drepper
2006-07-27 17:33 ` H. Peter Anvin
2006-07-27 17:44 ` Ulrich Drepper
2006-07-27 18:00 ` H. Peter Anvin
2006-07-27 17:33 ` Alan Cox
2006-07-27 17:33 ` O_CAREFUL flag to disable open() side effects H. Peter Anvin
2006-07-27 17:43 ` Russell King [this message]
2006-07-27 17:50 ` Ulrich Drepper
2006-07-27 18:05 ` Alan Cox
2006-07-27 18:03 ` H. Peter Anvin
2006-08-05 21:05 ` [RFC/PATCH] revoke/frevoke system calls V2 Pavel Machek
2006-07-27 18:06 ` Petr Baudis
2006-07-27 18:10 ` Pekka Enberg
2006-07-27 19:30 ` Horst H. von Brand
2006-07-28 3:40 ` Pekka J Enberg
2006-07-27 18:34 ` Alan Cox
2006-08-05 12:29 ` Pavel Machek
2006-08-07 5:42 ` Pekka J Enberg
2006-08-07 8:17 ` Edgar Toernig
2006-08-07 9:51 ` Pekka Enberg
2006-08-07 20:41 ` Edgar Toernig
2006-08-07 22:24 ` Chase Venters
2006-08-08 12:15 ` Alan Cox
2006-08-09 8:41 ` Edgar Toernig
2006-08-09 10:39 ` Alan Cox
2006-08-09 18:00 ` Edgar Toernig
2006-08-09 18:36 ` Alan Cox
2006-08-09 19:13 ` Pekka Enberg
2006-08-09 20:08 ` Edgar Toernig
2006-08-09 21:29 ` Edgar Toernig
2006-08-11 7:52 ` Helge Hafting
2006-08-08 12:29 ` Alan Cox
2006-08-08 12:31 ` Pekka Enberg
2006-08-08 12:57 ` Pavel Machek
2006-08-08 14:14 ` Alan Cox
2006-08-08 13:57 ` Pavel Machek
2006-08-09 8:41 ` Edgar Toernig
2006-08-09 10:42 ` Alan Cox
2006-08-09 18:00 ` Edgar Toernig
2006-08-09 18:35 ` Alan Cox
2006-08-09 19:14 ` Pekka Enberg
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