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    SubjectRe: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction abstraction
    Jeremy Fitzhardinge wrote:
    > Benjamin Herrenschmidt wrote:
    >
    >> On Mon, 2008-06-16 at 04:30 -0700, Jeremy Fitzhardinge wrote:
    >>
    >>
    >>> The only current user of this interface is mprotect
    >>>
    >>>
    >> Do you plan to use it with fork ultimately ?
    >>
    >>
    >
    > Good point, I'd overlooked that. I guess that means using it in
    > ptep_set_wrprotect().
    Along the lines of:

    --- a/include/asm-x86/pgtable.h Wed Jun 18 13:54:49 2008 -0700
    +++ b/include/asm-x86/pgtable.h Wed Jun 18 17:03:39 2008 -0700
    @@ -491,7 +491,11 @@
    static inline void ptep_set_wrprotect(struct mm_struct *mm,
    unsigned long addr, pte_t *ptep)
    {
    - clear_bit(_PAGE_BIT_RW, (unsigned long *)&ptep->pte);
    + pte_t pte = ptep_modify_prot_start(mm, addr, ptep);
    +
    + pte = pte_wrprotect(pte);
    +
    + ptep_modify_prot_commit(mm, addr, ptep, pte);
    pte_update(mm, addr, ptep);
    }

    J



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