From: Song Liu <song@kernel.org>
To: Yu Kuai <yukuai1@huaweicloud.com>
Cc: Gui-Dong Han <2045gemini@gmail.com>,
linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org,
baijiaju1990@outlook.com, stable@vger.kernel.org,
"yukuai (C)" <yukuai3@huawei.com>
Subject: Re: [PATCH v4] md/raid5: fix atomicity violation in raid5_cache_count
Date: Tue, 27 Feb 2024 14:28:00 -0800 [thread overview]
Message-ID: <CAPhsuW5u1SHCjw-0EUEvOp9-+nyh3s67Nio=OR=P1ftRTe33gA@mail.gmail.com> (raw)
In-Reply-To: <e0c5f9d4-6b65-02f7-2a8c-0484fd1f9815@huaweicloud.com>
On Thu, Feb 1, 2024 at 11:11 PM Yu Kuai <yukuai1@huaweicloud.com> wrote:
>
> Hi,
>
> 在 2024/01/30 15:37, Song Liu 写道:
> > On Thu, Jan 11, 2024 at 11:10 PM Gui-Dong Han <2045gemini@gmail.com> wrote:
> >>
> > [...]
> >>
> >> raid5_release_stripe(sh);
> >> - conf->max_nr_stripes++;
> >> + WRITE_ONCE(conf->max_nr_stripes, conf->max_nr_stripes + 1);
> >
> > This is weird. We are reading max_nr_stripes without READ_ONCE.
>
> We don't need READ_ONCE() here because writers are protected by
> 'cache_size_mutex', there are no concurrent writers, it's safe to
> read 'max_nr_stripes' directly.
OK, that makes sense. Applied to md-6.9.
Thanks,
Song
prev parent reply other threads:[~2024-02-27 22:28 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-12 7:10 [PATCH v4] md/raid5: fix atomicity violation in raid5_cache_count Gui-Dong Han
2024-01-14 3:12 ` Yu Kuai
2024-01-30 7:37 ` Song Liu
2024-02-02 7:11 ` Yu Kuai
2024-02-27 22:28 ` Song Liu [this message]
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