linux-kernel - Re: [PATCH 3/7] mm,madvise: call soft_offline_page() without MF_COUNT

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Date:   Mon, 07 Dec 2020 08:24:54 +0100
From:   Oscar Salvador <osalvador@...e.de>
To:     HORIGUCHI NAOYA(堀口　直也) <naoya.horiguchi@....com>
Cc:     Vlastimil Babka <vbabka@...e.cz>, akpm@...ux-foundation.org,
        n-horiguchi@...jp.nec.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        Dan Williams <dan.j.williams@...el.com>
Subject: Re: [PATCH 3/7] mm,madvise: call soft_offline_page() without
 MF_COUNT_INCREASED

On 2020-12-07 03:34, HORIGUCHI NAOYA wrote:
>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
>> index 869ece2a1de2..ba861169c9ae 100644
>> --- a/mm/memory-failure.c
>> +++ b/mm/memory-failure.c
>> @@ -1269,6 +1269,12 @@ static int memory_failure_dev_pagemap(unsigned 
>> long pfn, int flags,
>>  	if (!cookie)
>>  		goto out;
>> 
>> +	if (flags & MF_COUNT_INCREASED)
>> +		/*
>> +		 * Drop the extra refcount in case we come from madvise().
>> +		 */
>> +		put_page(page);
>> +
> 
> Should this if-block come before dax_lock_page() block?

Yeah, it should go first thing since as you noticed we kept the refcount 
if we fail.
Saturday brain... I will fix it.

Thanks Naoya

-- 
Oscar Salvador
SUSE L3