[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>
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index f69ff3c..5d56c2b 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -303,15 +303,15 @@
/* 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 @@
flush |= gmap_unlink_segment(gmap, table);
*table = _SEGMENT_ENTRY_INV;
}
+out:
up_read(&gmap->mm->mmap_sem);
if (flush)
gmap_flush_tlb(gmap);