ioctl32 unknown cmds with 2.6.24-rc1

[Geert Uytterhoeven]

On Thu, 25 Oct 2007, Arnd Bergmann wrote:
> On Thursday 25 October 2007, Geert Uytterhoeven wrote:
> > If you want to look into this, the question is just why these messages are
> > printed now, while they weren't printed before. I don't think any other
> > behavior got changed.
> 
> I'm not so sure about that. The reason that the messages are printed now
> is that there is no fallback handler for these ioctl numbers any more,
> but they are instead expected to be handled by the compat_blkdev_ioctl()
> function, which is only called for block devices.
> 
> My first idea was that the ioctl numbers are used on files that are
> not block devices, in this case the warning message would be (somewhat)
> appropriate.
> 
> Whenever we get one of these messages on a real block device, that is
> supposed to mean that an ioctl that was actually valid could not be
> executed, and compat_blkdev_ioctl() returned -ENOIOCTLCMD.

In many cases these ioctls can indeed not be handled.
E.g. when using `hdparm -tT /dev/ps3da', hdparm issues an ioctl to flush the
cache. But this ioctl is not supported, not before and not after 2.6.23.
Before 2.6.23, it didn't print the message, in 2.6.23, it does.

With kind regards,
 
Geert Uytterhoeven
Software Architect

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