[S390] gmap: always up mmap_sem properly

If gmap_unmap_segment figures that the segment was not mapped in the
first place, it need to up mmap_sem on exit.

Cc: <stable@kernel.org>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index f69ff3c1349..5d56c2b95b1 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -303,15 +303,15 @@ int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
                 /* Walk the guest addr space page table */
                 table = gmap->table + (((to + off) >> 53) & 0x7ff);
                 if (*table & _REGION_ENTRY_INV)
-                        return 0;
+                        goto out;
                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
                 table = table + (((to + off) >> 42) & 0x7ff);
                 if (*table & _REGION_ENTRY_INV)
-                        return 0;
+                        goto out;
                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
                 table = table + (((to + off) >> 31) & 0x7ff);
                 if (*table & _REGION_ENTRY_INV)
-                        return 0;
+                        goto out;
                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
                 table = table + (((to + off) >> 20) & 0x7ff);
 
@@ -319,6 +319,7 @@ int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
                 flush |= gmap_unlink_segment(gmap, table);
                 *table = _SEGMENT_ENTRY_INV;
         }
+out:
         up_read(&gmap->mm->mmap_sem);
         if (flush)
                 gmap_flush_tlb(gmap);