On Tue, 7 Feb 2017 17:33:47 +0300 "Kirill A. Shutemov" <[email protected]> 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?
