linux-kernel - Re: [PATCH 17/41] mm/mmap: move VMA locking before anon_vma_lock

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Date:   Thu, 19 Jan 2023 10:31:10 +0100
From:   Michal Hocko <mhocko@...e.com>
To:     Suren Baghdasaryan <surenb@...gle.com>
Cc:     akpm@...ux-foundation.org, michel@...pinasse.org,
        jglisse@...gle.com, vbabka@...e.cz, hannes@...xchg.org,
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Subject: Re: [PATCH 17/41] mm/mmap: move VMA locking before
 anon_vma_lock_write call

On Wed 18-01-23 13:48:13, Suren Baghdasaryan wrote:
> On Wed, Jan 18, 2023 at 1:33 PM Michal Hocko <mhocko@...e.com> wrote:
[...]
> > So it will become:
> > Move VMA flag modification (which now implies VMA locking) before
> > vma_adjust_trans_huge() to ensure the modifications are done after VMA
> > has been locked. Because vma_adjust_trans_huge() modifies the VMA and such
> > modifications should be done under VMA write-lock protection.
> >
> > which is effectivelly saying
> > vma_adjust_trans_huge() modifies the VMA and such modifications should
> > be done under VMA write-lock protection so move VMA flag modifications
> > before so all of them are covered by the same write protection.
> >
> > right?
> 
> Yes, and the wording in the latter version is simpler to understand
> IMO, so I would like to adopt it. Do you agree?

of course.
-- 
Michal Hocko
SUSE Labs