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Subject: Re: [PATCH v1] mm, hwpoison: remove obsolete comment
To:     Naoya Horiguchi <naoya.horiguchi@linux.dev>, linux-mm@kvack.org
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Tony Luck <tony.luck@intel.com>,
        Naoya Horiguchi <naoya.horiguchi@nec.com>,
        linux-kernel@vger.kernel.org
References: <20220125025601.3054511-1-naoya.horiguchi@linux.dev>
From:   Anshuman Khandual <anshuman.khandual@arm.com>
Message-ID: <a2b71789-5072-9b40-1839-a662d9f64064@arm.com>
Date:   Tue, 25 Jan 2022 11:14:09 +0530
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On 1/25/22 8:26 AM, Naoya Horiguchi wrote:
> From: Naoya Horiguchi <naoya.horiguchi@nec.com>
> 
> With the introduction of mf_mutex, most of memory error handling
> process is mutually exclusive, so the in-line comment about
> subtlety about double-checking PageHWPoison is no more correct.
> So remove it.
> 
> Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
> Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
> ---
>  mm/memory-failure.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 4c9bd1d37301..a6a1e02759e7 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -2146,12 +2146,6 @@ static int __soft_offline_page(struct page *page)
>  		.gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
>  	};
>  
> -	/*
> -	 * Check PageHWPoison again inside page lock because PageHWPoison
> -	 * is set by memory_failure() outside page lock. Note that
> -	 * memory_failure() also double-checks PageHWPoison inside page lock,
> -	 * so there's no race between soft_offline_page() and memory_failure().
> -	 */
>  	lock_page(page);
>  	if (!PageHuge(page))
>  		wait_on_page_writeback(page);
> 

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>