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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Richard Purdie <rpurdie@rpsys.net>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Flaw in ide_unregister()
Date: Sun, 02 Jan 2005 14:36:49 +0000	[thread overview]
Message-ID: <1104674725.14712.50.camel@localhost.localdomain> (raw)
In-Reply-To: <007e01c4ef30$f23ba3c0$0f01a8c0@max>

On Gwe, 2004-12-31 at 12:04, Richard Purdie wrote:
> I've been having some problems with calls to ide_unregister() (in ide.c).
> 
> This function is declared void which should mean it always succeeds and yet 
> it can fail *silently* under the following condition:

Actually in 2.4.x and 2.6.x (except 2.6.9-ac and 2.6.10-ac) its
essentially unusable and full of races and should always be avoided.

> 3. Add a return value. What does ide-cs.c do with it though? The hardware is 
> gone. (doesn't help)

In 2.6.9-ac and 2.6.10-ac the ide_unregister_hwif calls return an error
if the drive is in use. At this point the ide-cs code still throws it
away. The -ac code IDE also adds "removed_hwif_iops" so the bits are
there for the correct result which is something like

	if(ide_unregister_hwif(hwif) < 0 {
		printk("Whine whine...");
		removed_hwif_ops(hwif);
		while(ide_unregister_hwif(hwif) < 0)
			msleep(1000);
	}

I've just not had time yet to propogate this into the drivers and into
the new PCI helper for hotplugging IDE controllers.

Alan


  reply	other threads:[~2005-01-02 15:41 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-12-31 12:04 Flaw in ide_unregister() Richard Purdie
2005-01-02 14:36 ` Alan Cox [this message]
2005-01-09 22:37   ` Richard Purdie
2005-01-10 11:09     ` Alan Cox
2005-01-10 12:39       ` Richard Purdie
2005-01-10 19:23         ` Alan Cox
2005-01-10 21:17           ` Richard Purdie

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