On Wed, Sep 12, 2018 at 05:08:52PM +0200, Arnd Bergmann wrote:

The .ioctl and .compat_ioctl file operations have the same prototype so they can both point to the same function, which works great almost all the time when all the commands are compatible.

One exception is the s390 architecture, where a compat pointer is only 31 bit wide, and converting it into a 64-bit pointer requires calling compat_ptr(). Most drivers here will ever run in s390, but since we now have a generic helper for it, it's easy enough to use it consistently.

I double-checked all these drivers to ensure that all ioctl arguments are used as pointers or are ignored, but are not interpreted as integer values.

Signed-off-by: Arnd Bergmann arnd@arndb.de

Acked-by: Greg Kroah-Hartman gregkh@linuxfoundation.org