Re: [Xen-devel] [PATCH] xen: simplify balloon_first_page() with list_first_entry_or_null()

[Jeff Liu <jeff.liu@xxxxxxxxxx>]

On 11/13, 2013 20:09 PM, David Vrabel wrote:
> On 13/11/13 11:44, Jeff Liu wrote:
>> From: Jie Liu <jeff.liu@xxxxxxxxxx>
>>
>> Simplify the code logic of balloon_first_page() by replacing
>> the combination of list_empty() and list_first_entry() with
>> list_first_entry_or_null().  As a net win, we can change this
>> routine to inline as now it's one line.
>>
>> Signed-off-by: Jie Liu <jeff.liu@xxxxxxxxxx>
>>
>> ---
>>  drivers/xen/balloon.c |    7 +++----
>>  1 file changed, 3 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
>> index b232908..0e4ca20 100644
>> --- a/drivers/xen/balloon.c
>> +++ b/drivers/xen/balloon.c
>> @@ -157,11 +157,10 @@ static struct page *balloon_retrieve(bool 
>> prefer_highmem)
>>      return page;
>>  }
>>  
>> -static struct page *balloon_first_page(void)
>> +static inline struct page *balloon_first_page(void)
>>  {
>> -    if (list_empty(&ballooned_pages))
>> -            return NULL;
>> -    return list_entry(ballooned_pages.next, struct page, lru);
>> +    return list_first_entry_or_null(&ballooned_pages,
>> +                                    struct page, lru);
>>  }
> 
> There's only one user of balloon_first_page(), can you remove
> balloon_first_page() and just use list_first_entry_or_null()?
Sure, will post the revised version a little while.

Thanks,
-Jeff

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