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SubjectRe: return value of ptep_get_and_clear
Kumar Gala wrote:
> ptep_get_and_clear has a signature that looks something like:
>
> static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned
> long addr,
> pte_t *ptep)
>
> It appears that its suppose to return the pte_t pointed to by ptep
> before its modified. Why do we bother doing this? The caller seems
> perfectly able to dereference ptep and hold on to it. Am I missing
> something here?
>
> If not, I'll work up a set of patches to change ptep_get_and_clear and
> its callers for post 2.6.12 release.
>
> - kumar

Because it is an atomic operation. If you dereference it before
ptep_get_and_clear() it could change in between.

--
Brian Gerst
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