[PATCH v6 08/13] mm: call pgmap->ops->page_free for DEVICE_GENERIC pages

[Felix Kuehling]

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 at amd.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---
>