On 20/12/06, Peter Zijlstra <[email protected]> wrote:
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;
+ }
Having the assignment of "ret = 1;" inside the loop seems a little
pointless. Perhaps gcc can optimize it, but still, that assignment
really only needs to happen once outside the loop.
-unlock:
- pte_unmap_unlock(pte, ptl);
+ pte_unmap_unlock(ptep, ptl);
out:
return ret;
}
--
Jesper Juhl <[email protected]>
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please http://www.expita.com/nomime.html
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