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    SubjectRe: [patch 6/7] um: Convert mmapper to unlocked_ioctl
    On Thu, 15 Oct 2009 15:00:34 +0200
    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 <>
    > > Cc: Jeff Dike <>
    > 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.

    That is wrong.

    SuS requires an unknown ioctl code returns -ENOTTY. If the code is
    currently remapping it to EINVAL then it wants fixing.

     \ /
      Last update: 2009-10-15 17:41    [W:0.020 / U:97.116 seconds]
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