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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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