Re: [PATCH 3/3] mm,generic: only flush the local TLB in ptep_set_access_flags

[Rik van Riel]

On 10/26/2012 02:48 PM, Linus Torvalds wrote:
> On Fri, Oct 26, 2012 at 11:46 AM, Rik van Riel <riel@xxxxxxxxxx> wrote:
> > The function ptep_set_access_flags is only ever used to upgrade
> > access permissions to a page.
>
> NOTE: It's *not* "access permissions". It's "access flags".
>
> Big difference. This is not about permissions at all.

It looks like do_wp_page also sets the write bit in the pte
"entry" before passing it to ptep_set_access_flags, making
that the place where the write bit is set in the pte.

Is this a bug in do_wp_page?

Am I reading things wrong?

reuse:
                flush_cache_page(vma, address, pte_pfn(orig_pte));
                entry = pte_mkyoung(orig_pte);
                entry = maybe_mkwrite(pte_mkdirty(entry), vma);
                if (ptep_set_access_flags(vma, address, page_table, 
entry,1))
                        update_mmu_cache(vma, address, page_table);

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