lkml.org 
[lkml]   [2006]   [Dec]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] mm: fix page_mkclean_one (was: 2.6.19 file content corruption on ext3)
On 20/12/06, Peter Zijlstra <a.p.zijlstra@chello.nl> 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 <a.p.zijlstra@chello.nl>
> ---
> 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 <jesper.juhl@gmail.com>
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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-12-20 12:41    [W:0.944 / U:0.052 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site