Re: [PATCH] ring-buffer: remove obsolete comment for free_buffer_page()

From: Vlastimil Babka
Date: Thu Mar 16 2023 - 04:29:42 EST


On 3/15/23 16:53, Mukesh Ojha wrote:
>
>
> On 3/15/2023 9:21 PM, Mukesh Ojha wrote:
>>
>>
>> On 3/15/2023 7:54 PM, Vlastimil Babka wrote:
>>> The comment refers to mm/slob.o which is being removed. It comes from
>
> nit: mm/slob.c

Thanks, Steven can you fix that up while picking the patch, or need v2?

> -- Mukesh
>
>>
>>
>>> commit ed56829cb319 ("ring_buffer: reset buffer page when freeing") and
>>> according to Steven the borrowed code was a page mapcount and mapping
>>> reset, which was later removed by commit e4c2ce82ca27 ("ring_buffer:
>>> allocate buffer page pointer"). Thus the comment is not accurate anyway,
>>> remove it.
>>>
>>> Reported-by: Mike Rapoport <mike.rapoport@xxxxxxxxx>
>>> Suggested-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
>>> Fixes: e4c2ce82ca27 ("ring_buffer: allocate buffer page pointer")
>>> Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
>>> ---
>>>   kernel/trace/ring_buffer.c | 4 ----
>>>   1 file changed, 4 deletions(-)
>>>
>>> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
>>> index af50d931b020..c6f47b6cfd5f 100644
>>> --- a/kernel/trace/ring_buffer.c
>>> +++ b/kernel/trace/ring_buffer.c
>>> @@ -354,10 +354,6 @@ static void rb_init_page(struct buffer_data_page
>>> *bpage)
>>>       local_set(&bpage->commit, 0);
>>>   }
>>> -/*
>>> - * Also stolen from mm/slob.c. Thanks to Mathieu Desnoyers for pointing
>>> - * this issue out.
>>> - */
>>
>> Thanks for the clean up.
>>
>> Reviewed-by: Mukesh Ojha <quic_mojha@xxxxxxxxxxx>

Thanks.

>>
>> -- Mukesh
>>
>>>   static void free_buffer_page(struct buffer_page *bpage)
>>>   {
>>>       free_page((unsigned long)bpage->page);