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>

diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index d402b19f1df2a301024949bcb32764212bd3ac62..387c7c60b5b8d65a50bec087a54288a1cc913519 100644 (file)
--- 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;