Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 19 Jan 2023 10:31:10 +0100
From:   Michal Hocko <mhocko@suse.com>
To:     Suren Baghdasaryan <surenb@google.com>
Cc:     akpm@linux-foundation.org, michel@lespinasse.org,
        jglisse@google.com, vbabka@suse.cz, hannes@cmpxchg.org,
        mgorman@techsingularity.net, dave@stgolabs.net,
        willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org,
        ldufour@linux.ibm.com, laurent.dufour@fr.ibm.com,
        paulmck@kernel.org, luto@kernel.org, songliubraving@fb.com,
        peterx@redhat.com, david@redhat.com, dhowells@redhat.com,
        hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev,
        punit.agrawal@bytedance.com, lstoakes@gmail.com,
        peterjung1337@gmail.com, rientjes@google.com,
        axelrasmussen@google.com, joelaf@google.com, minchan@google.com,
        jannh@google.com, shakeelb@google.com, tatashin@google.com,
        edumazet@google.com, gthelen@google.com, gurua@google.com,
        arjunroy@google.com, soheil@google.com, hughlynch@google.com,
        leewalsh@google.com, posk@google.com, linux-mm@kvack.org,
        linux-arm-kernel@lists.infradead.org,
        linuxppc-dev@lists.ozlabs.org, x86@kernel.org,
        linux-kernel@vger.kernel.org, kernel-team@android.com
Subject: Re: [PATCH 17/41] mm/mmap: move VMA locking before
 anon_vma_lock_write call
Message-ID: <Y8kN3stHeEyAoB+D@dhcp22.suse.cz>
References: <20230109205336.3665937-1-surenb@google.com>
 <20230109205336.3665937-18-surenb@google.com>
 <Y8a734ufLZjPHgtT@dhcp22.suse.cz>
 <CAJuCfpGoYaF2-z7FCiN4X8gEGD6nAwnQC+=n3tUHuMWZa7zx8Q@mail.gmail.com>
 <Y8e6lm76fIoT0603@dhcp22.suse.cz>
 <CAJuCfpHtV5xEo97X62uR=LXjK6wQMJXhhV2OxXexTfyudGOptw@mail.gmail.com>
 <Y8hls4MH353ZnlQu@dhcp22.suse.cz>
 <CAJuCfpF3j5Sx+D5p5QPCHP4jcWZUiYm=FfUNYhc6QyHZQvDgpw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAJuCfpF3j5Sx+D5p5QPCHP4jcWZUiYm=FfUNYhc6QyHZQvDgpw@mail.gmail.com>
Precedence: bulk

On Wed 18-01-23 13:48:13, Suren Baghdasaryan wrote:
> On Wed, Jan 18, 2023 at 1:33 PM Michal Hocko <mhocko@suse.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