Re: Flaw in ide_unregister()

[Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>]

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

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