It may be useful for kmap_atomic_pfn() and iomap_atomic_prot_pfn()
to check invalid kmap usage as well as kmap_atomic.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
LKML-Reference: <20090311143449.GB22244@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>