If the page is already mapped resp. already unmapped, bail out.
Signed-off-by: NChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: NNicholas Miehlbradt <nicholas@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220926075726.2846-3-nicholas@linux.ibm.com