Since the shift count settable there is used for shifting values
of type "unsigned long", its value must not match or exceed
BITS_PER_LONG (otherwise the shift operations are undefined).

Similarly, the value must not be negative (but -1 must be
permitted, as that's the value used to distinguish the case of
the fine grained flushing being disabled).
Signed-off-by: NJan Beulich <jbeulich@suse.com>
Cc: Alex Shi <alex.shi@intel.com>
Link: http://lkml.kernel.org/r/5049B65C020000780009990C@nat28.tlf.novell.comSigned-off-by: NIngo Molnar <mingo@kernel.org>