[PATCH] makedumpfile: clean up draft patch

[Baoquan He]

> > +static void update_cycle(unsigned long long max, struct cycle *cycle)
> > +{
> > +	cycle->start_pfn= cycle->end_pfn + 1;
> > +	cycle->end_pfn=  cycle->start_pfn + info->pfn_cyclic;
> > +
> > +	if (cycle->end_pfn > max)
> > +		cycle->end_pfn = max;
> > +}
> 
> According to this function, you must treat a range of a cycle
> as below:
> 
>    |<----------------- a cycle ------------------->|
> ---+-----------+-----------+-----------+-----------+----
>    |   pfn:N   |  pfn:N+1  |  pfn:N+2  |  pfn:N+3  | ...
> ---+-----------+-----------+-----------+-----------+----
>          A                                   A
>          |                                   |
>      start_pfn                            end_pfn
> 
> However, the existing code treat it as:
> 
>    |<------------ a cycle ------------>|
> ---+-----------+-----------+-----------+-----------+----
>    |   pfn:N   |  pfn:N+1  |  pfn:N+2  |  pfn:N+3  | ...
> ---+-----------+-----------+-----------+-----------+----
>          A                                   A
>          |                                   |
>      start_pfn                            end_pfn
> 
> This can be implied from the current iterator like below:
> 
>      for (pfn = start_pfn; pfn < end_pfn; pfn++) {
>                            ^^^^^^^^^^^^^^
> In short, the existing code will not work correctly.

Yeah, you are quite right. This need be corrected. Will change in formal
patch.

> 
> You may feel this design is strange.
> This came from the fact that the end of the region's *address*
> is the head of pfn:N+1 while it can also be said the tail of pfn:N.
> (And this came from the initial version.)
> 
> BTW, info->cyclic_start_pfn and info->cyclic_end_pfn are no longer
> used, we can get rid of those from makedumpfile.h.

Ok, will change.



> 
>