While doing some compat_ioctl conversions I noticed a few issues in
compat_sys_ioctl:

- It is not completely compatible to old ->ioctl because the traditional
  common ioctls are not checked before it.  I added a check for those.  The
  main advantage is that the handler now works the same as a traditional
  handler even when it returns -EINVAL

- The private socket ioctl check should only apply for sockets.

- There was a security hook missing.  Drawback is that it uses the same
  hook now, and the LSM module cannot distingush between 32bit and 64bit
  clients.  But it'll have to live with that for now.
Signed-off-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>