From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The patch below fixes a 2.6 mm problem. Without this patch, zeromapped
pages are not flushed properly when they are swapped out.
What happens is that the page->index field is zero for page table pages
corresponding to the zeromapped range. This causes ptep_to_address() to
return an incorrect virtual address with the result that PTEs are never
invalidated at swap-out...
The fix below mirrors the remap_pmd_range() case.
mm/memory.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)
diff -puN mm/memory.c~zeromap_pmd_range-fix mm/memory.c
--- 25/mm/memory.c~zeromap_pmd_range-fix 2003-08-23 14:01:59.000000000 -0700
+++ 25-akpm/mm/memory.c 2003-08-23 14:01:59.000000000 -0700
@@ -810,17 +810,18 @@ static void zeromap_pte_range(pte_t * pt
static inline int zeromap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address,
unsigned long size, pgprot_t prot)
{
- unsigned long end;
+ unsigned long base, end;
+ base = address & PGDIR_MASK;
address &= ~PGDIR_MASK;
end = address + size;
if (end > PGDIR_SIZE)
end = PGDIR_SIZE;
do {
- pte_t * pte = pte_alloc_map(mm, pmd, address);
+ pte_t * pte = pte_alloc_map(mm, pmd, base + address);
if (!pte)
return -ENOMEM;
- zeromap_pte_range(pte, address, end - address, prot);
+ zeromap_pte_range(pte, base + address, end - address, prot);
pte_unmap(pte);
address = (address + PMD_SIZE) & PMD_MASK;
pmd++;
_