On Thu, 7 Jan 2016 13:08:21 +0800
Xunlei Pang <xlpang at redhat.com> wrote:
> On 01/07/2016 at 10:36 AM, Minfei Huang wrote:
> > On 01/07/16 at 10:14am, Xunlei Pang wrote:
> >>>> +static int
> >>>> +kexec_mark_range(unsigned long start, unsigned long end, bool protect)
> >>>> +{
> >>>> + struct page *page;
> >>>> + unsigned int nr_pages;
> >>>> +
> >>>> + /* For physical range: [start, end] */
> >>>> + if (!start || !end || start > end)
> >>>> + return 0;
> >>> Hi, Xunlei.
> >>>
> >>> if (start > end)
> >>> return 0;
> >> If both start and end are zero, we want to return directly, so the two
> >> more check doesn't hurt.
> > How about if the start is equal to 0, and end is larger than 0? It is
> > better to make code more robust, although it never happen in currect
> > kexec code.
>
> Hmm, this will be better:
>
> if (!end || start > end)
> return 0;
>
> it handles the common case not using crash_low_res(start and end are 0).
Hm, if both start and end are 0, then what about using this condition:
if (start >= end)
return 0;
I think it's good enough, because if start is equal to end, then
there's nothing to protect anyway.
Regards,
Petr Tesarik
