Re: [PATCH] mprotect: drop overprotective lock_pte_protection()

[Andrew Morton]

On Tue,  7 Feb 2017 17:33:47 +0300 "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> wrote:

> lock_pte_protection() uses pmd_lock() to make sure that we have stable
> PTE page table before walking pte range.
> 
> That's not necessary. We only need to make sure that PTE page table is
> established. It cannot vanish under us as long as we hold mmap_sem at
> least for read.
> 
> And we already have helper for that -- pmd_trans_unstable().

http://ozlabs.org/~akpm/mmots/broken-out/mm-mprotect-use-pmd_trans_unstable-instead-of-taking-the-pmd_lock.patch
already did this?