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Date:   Thu, 18 Apr 2019 17:09:51 +0300
From:   Cyrill Gorcunov <gorcunov@gmail.com>
To:     Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>
Cc:     mhocko@kernel.org, akpm@linux-foundation.org,
        arunks@codeaurora.org, brgl@bgdev.pl, geert+renesas@glider.be,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        mguzik@redhat.com, rppt@linux.ibm.com, vbabka@suse.cz,
        Laurent Dufour <ldufour@linux.ibm.com>
Subject: Re: [PATCH] prctl_set_mm: downgrade mmap_sem to read lock
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On Thu, Apr 18, 2019 at 03:50:39PM +0200, Michal Koutn? wrote:
> I learnt, it's, alas, too late to drop the non PRCTL_SET_MM_MAP calls
> [1], so at least downgrade the write acquisition of mmap_sem as in the
> patch below (that should be stacked on the previous one or squashed).
> 
> Cyrill, you mentioned lock changes in [1] but the link seems empty. Is
> it supposed to be [2]? That could be an alternative to this patch after
> some refreshments and clarifications.

Yes, seems so. From a glance the patch shold be ok. Michal will review
it more carefully today. Thanks!