diff options
| author | David Hildenbrand <dahi@linux.vnet.ibm.com> | 2016-05-27 18:57:33 +0200 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2016-06-20 09:55:16 +0200 |
| commit | 5b6c963bcef5c3a857e3f8ba84aa9380069fc95f (patch) | |
| tree | ea98bc0e529c3e1b7c305e1710f9ae24d1657752 /arch/s390/mm | |
| parent | 4a49443924731823da2e9b3ae9311b74a34e7ed8 (diff) | |
s390/mm: allow to check if a gmap shadow is valid
It will be very helpful to have a mechanism to check without any locks
if a given gmap shadow is still valid and matches the given properties.
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390/mm')
| -rw-r--r-- | arch/s390/mm/gmap.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 4a1434bc2f0e..d00e4abb559e 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -1408,6 +1408,26 @@ static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce, } /** + * gmap_shadow_valid - check if a shadow guest address space matches the + * given properties and is still valid + * @sg: pointer to the shadow guest address space structure + * @asce: ASCE for which the shadow table is requested + * @edat_level: edat level to be used for the shadow translation + * + * Returns 1 if the gmap shadow is still valid and matches the given + * properties, the caller can continue using it. Returns 0 otherwise, the + * caller has to request a new shadow gmap in this case. + * + */ +int gmap_shadow_valid(struct gmap *sg, unsigned long asce, int edat_level) +{ + if (sg->removed) + return 0; + return sg->orig_asce == asce && sg->edat_level == edat_level; +} +EXPORT_SYMBOL_GPL(gmap_shadow_valid); + +/** * gmap_shadow - create/find a shadow guest address space * @parent: pointer to the parent gmap * @asce: ASCE for which the shadow table is created |