linux-ext4 - Re: [PATCH v6 08/13] mm: call pgmap->ops->page_free for DEVICE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 16 Aug 2021 15:00:49 -0400
From:   Felix Kuehling <felix.kuehling@....com>
To:     Christoph Hellwig <hch@....de>, Alex Sierra <alex.sierra@....com>
Cc:     akpm@...ux-foundation.org, linux-mm@...ck.org,
        rcampbell@...dia.com, linux-ext4@...r.kernel.org,
        linux-xfs@...r.kernel.org, amd-gfx@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org, jgg@...dia.com,
        jglisse@...hat.com, Roger Pau Monne <roger.pau@...rix.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>
Subject: Re: [PATCH v6 08/13] mm: call pgmap->ops->page_free for
 DEVICE_GENERIC pages


Am 2021-08-15 um 11:40 a.m. schrieb Christoph Hellwig:
> On Fri, Aug 13, 2021 at 01:31:45AM -0500, Alex Sierra wrote:
>> Add MEMORY_DEVICE_GENERIC case to free_zone_device_page callback.
>> Device generic type memory case is now able to free its pages properly.
> How is this going to work for the two existing MEMORY_DEVICE_GENERIC
> that now change behavior?  And which don't have a ->page_free callback
> at all?

That's a good catch. Existing drivers shouldn't need a page_free
callback if they didn't have one before. That means we need to add a
NULL-pointer check in free_device_page.

Regards,
  Felix


>
>> Signed-off-by: Alex Sierra <alex.sierra@....com>
>> ---
>>  mm/memremap.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/memremap.c b/mm/memremap.c
>> index 5aa8163fd948..5773e15b6ac9 100644
>> --- a/mm/memremap.c
>> +++ b/mm/memremap.c
>> @@ -459,7 +459,7 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
>>  EXPORT_SYMBOL_GPL(get_dev_pagemap);
>>  
>>  #ifdef CONFIG_DEV_PAGEMAP_OPS
>> -static void free_device_private_page(struct page *page)
>> +static void free_device_page(struct page *page)
>>  {
>>  
>>  	__ClearPageWaiters(page);
>> @@ -498,7 +498,8 @@ void free_zone_device_page(struct page *page)
>>  		wake_up_var(&page->_refcount);
>>  		return;
>>  	case MEMORY_DEVICE_PRIVATE:
>> -		free_device_private_page(page);
>> +	case MEMORY_DEVICE_GENERIC:
>> +		free_device_page(page);
>>  		return;
>>  	default:
>>  		return;
>> -- 
>> 2.32.0
> ---end quoted text---
>