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Subject: Re: [PATCH 2/5] swap: fix do_swap_page() race with swapoff
To:     "Huang, Ying" <ying.huang@intel.com>,
        Miaohe Lin <linmiaohe@huawei.com>
Cc:     akpm@linux-foundation.org, hannes@cmpxchg.org, mhocko@suse.com,
        iamjoonsoo.kim@lge.com, vbabka@suse.cz, alex.shi@linux.alibaba.com,
        willy@infradead.org, minchan@kernel.org, richard.weiyang@gmail.com,
        hughd@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org
References: <20210408130820.48233-1-linmiaohe@huawei.com>
 <20210408130820.48233-3-linmiaohe@huawei.com>
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From:   Tim Chen <tim.c.chen@linux.intel.com>
Message-ID: <c9bb0a8a-72ca-d9b4-4c31-d4d8cfde0b4c@linux.intel.com>
Date:   Tue, 13 Apr 2021 12:24:15 -0700
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On 4/12/21 6:27 PM, Huang, Ying wrote:

> 
> This isn't the commit that introduces the race.  You can use `git blame`
> find out the correct commit.  For this it's commit 0bcac06f27d7 "mm,
> swap: skip swapcache for swapin of synchronous device".
> 
> And I suggest to merge 1/5 and 2/5 to make it easy to get the full
> picture.

I'll suggest make fix to do_swap_page race with get/put_swap_device
as a first patch. Then the per_cpu_ref stuff in patch 1 and patch 2 can
be combined together.

Tim