Re: [PATCH 1/5] s390x/mm: cleanup gmap_pte_op_walk()

[Cornelia Huck <cohuck@redhat.com>]

On Wed, 20 Dec 2017 16:52:56 +0100
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> From: David Hildenbrand <david@redhat.com>
> 
> gmap_mprotect_notify() refuses shadow gmaps. Turns out that
> a) gmap_protect_range()
> b) gmap_read_table()
> c) gmap_pte_op_walk()
> 
> Are never called for gmap shadows. And never should be. This dates back
> to gmap shadow prototypes where we allowed to call mprotect_notify() on
> the gmap shadow (to get notified about the prefix pages getting removed).
> This is avoided by always getting notified about any change on the gmap
> shadow.
> 
> The only real function for walking page tables on shadow gmaps is
> gmap_table_walk().
> 
> So, essentially, these functions should never get called and
> gmap_pte_op_walk() can be cleaned up. Add some checks to callers of
> gmap_pte_op_walk().
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> Message-Id: <20171110151805.7541-1-david@redhat.com>
> Reviewed-by: Janosch Frank <frankja@linux.vnet.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  arch/s390/mm/gmap.c | 23 ++++++++---------------
>  1 file changed, 8 insertions(+), 15 deletions(-)

Acked-by: Cornelia Huck <cohuck@redhat.com>