Messages in this thread | | | Date | Wed, 20 Dec 2006 12:39:09 +0100 | From | "Jesper Juhl" <> | Subject | Re: [PATCH] mm: fix page_mkclean_one (was: 2.6.19 file content corruption on ext3) |
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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/
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