Messages in this thread | | | Date | Thu, 15 Oct 2009 16:50:34 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [patch 6/7] um: Convert mmapper to unlocked_ioctl |
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On Thu, 15 Oct 2009, Arnd Bergmann wrote:
> On Thursday 15 October 2009, Thomas Gleixner wrote: > > The ioctl is empty and needs no serialization. We might remove it > > completely but that would change the return value from -ENOIOCTLCMD to > > -ENOTTY. > > > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > > Cc: Jeff Dike <jdike@addtoit.com> > > This one is tricky if you want to get it right according to the > book. ENOIOCTLCMD is never a valid return code for user space, > but sys_ioctl passes it down anyway. > > However, returning -ENOIOCTLCMD from an *unlocked_ioctl* function > automatically gets turned into -EINVAL. It does this to allow > the same functions to be used for unlocked_ioctl and compat_ioctl. > In effect, this patch is functionally identical to removing the > ioctl function, which I think is what should be done here.
Yeah, we get either -ENOTTY or -EINVAL which always changes the user space return value. So yes, removing it at least saves some line of code :)
Thanks,
tglx
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