fix page_mkclean_one()

it had several issues:
 - it failed to flush the cache
 - it failed to flush the tlb
 - it failed to do s390 (s390 guys, please verify this is now correct)

Also, clear in a loop to ensure SMP safeness as suggested by Arjan.

Signed-off-by: Peter Zijlstra <[EMAIL PROTECTED]>
---
 mm/rmap.c |   29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

Index: linux-2.6/mm/rmap.c
===================================================================
--- linux-2.6.orig/mm/rmap.c
+++ linux-2.6/mm/rmap.c
@@ -432,7 +432,7 @@ static int page_mkclean_one(struct page 
 {
        struct mm_struct *mm = vma->vm_mm;
        unsigned long address;
-       pte_t *pte, entry;
+       pte_t *ptep;
        spinlock_t *ptl;
        int ret = 0;
 
@@ -440,22 +440,23 @@ static int page_mkclean_one(struct page 
        if (address == -EFAULT)
                goto out;
 
-       pte = page_check_address(page, mm, address, &ptl);
-       if (!pte)
+       ptep = page_check_address(page, mm, address, &ptl);
+       if (!ptep)
                goto out;
 
-       if (!pte_dirty(*pte) && !pte_write(*pte))
-               goto unlock;
-
-       entry = ptep_get_and_clear(mm, address, pte);
-       entry = pte_mkclean(entry);
-       entry = pte_wrprotect(entry);
-       ptep_establish(vma, address, pte, entry);
-       lazy_mmu_prot_update(entry);
-       ret = 1;
+       while (pte_dirty(*ptep) || pte_write(*ptep)) {
+               pte_t entry = ptep_get_and_clear(mm, address, ptep);
+               flush_cache_page(vma, address, pte_pfn(entry));
+               flush_tlb_page(vma, address);
+               (void)page_test_and_clear_dirty(page); /* do the s390 thing */
+               entry = pte_wrprotect(entry);
+               entry = pte_mkclean(entry);
+               set_pte_at(vma, address, ptep, entry);
+               lazy_mmu_prot_update(entry);
+               ret = 1;
+       }
 
-unlock:
-       pte_unmap_unlock(pte, ptl);
+       pte_unmap_unlock(ptep, ptl);
 out:
        return ret;
 }


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