Re: [PATCH 1/3] ring-buffer: make the buffer a true circular link list

[Lai Jiangshan <laijs@cn.fujitsu.com>]

Steven Rostedt wrote:
> On Thu, 11 Jun 2009, Lai Jiangshan wrote:
> 
>>> -	list_splice(&pages, head);
>>> +	/*
>>> +	 * The ring buffer page list is a circular list that does not
>>> +	 * start and end with a list head. All page list items point to
>>> +	 * other pages. Remove one of the pages, init its list head,
>>> +	 * and use list splice to move the rest of the pages to it.
>>> +	 */
>>> +	bpage = list_entry(pages.next, struct buffer_page, list);
>>> +	list_del_init(&bpage->list);
>>> +	cpu_buffer->pages = &bpage->list;
>>> +
>>> +	list_splice(&pages, cpu_buffer->pages);
>>> +
>> Is it proper?
>>
>> 	cpu_buffer->pages = pages.next;
>> 	list_del(&pages);
>>
> 
> Not sure what you are asking here?
> 


I'm not sure whether these 4 lines:
	bpage = list_entry(pages.next, struct buffer_page, list);
	list_del_init(&bpage->list);
	cpu_buffer->pages = &bpage->list;

	list_splice(&pages, cpu_buffer->pages);
equal to these 2 lines:
 	cpu_buffer->pages = pages.next;
 	list_del(&pages);

If there are equivalent, I think the second one
are simpler. It may be not a really necessarily cleanup.

What I asked is: if there are equivalent, could you use these two line:
 	cpu_buffer->pages = pages.next;
 	list_del(&pages);

Lai.