s390/mm,vmem: fix vmem_add_mem()/vmem_remove_range()

vmem_add_mem() should only then insert a large page if pmd_none() is true
for the specific entry. We might have a leftover from a previous mapping.
In addition make vmem_remove_range()'s page table walk code more complete
and fix a couple of potential endless loops (which can never happen :).

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index d402b19f1df2..387c7c60b5b8 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -109,8 +109,8 @@ static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
                 pm_dir = pmd_offset(pu_dir, address);
 
 #if defined(CONFIG_64BIT) && !defined(CONFIG_DEBUG_PAGEALLOC)
-                if (MACHINE_HAS_EDAT1 && address && !(address & ~PMD_MASK) &&
-                    (address + PMD_SIZE <= end)) {
+                if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address &&
+                    !(address & ~PMD_MASK) && (address + PMD_SIZE <= end)) {
                         pte_val(pte) |= _SEGMENT_ENTRY_LARGE;
                         pmd_val(*pm_dir) = pte_val(pte);
                         address += PMD_SIZE;
@@ -151,12 +151,20 @@ static void vmem_remove_range(unsigned long start, unsigned long size)
         pte_val(pte) = _PAGE_TYPE_EMPTY;
         while (address < end) {
                 pg_dir = pgd_offset_k(address);
+                if (pgd_none(*pg_dir)) {
+                        address += PGDIR_SIZE;
+                        continue;
+                }
                 pu_dir = pud_offset(pg_dir, address);
-                if (pud_none(*pu_dir))
+                if (pud_none(*pu_dir)) {
+                        address += PUD_SIZE;
                         continue;
+                }
                 pm_dir = pmd_offset(pu_dir, address);
-                if (pmd_none(*pm_dir))
+                if (pmd_none(*pm_dir)) {
+                        address += PMD_SIZE;
                         continue;
+                }
                 if (pmd_large(*pm_dir)) {
                         pmd_clear(pm_dir);
                         address += PMD_SIZE;