Messages in this thread | | | Date | Thu, 7 Jan 2016 10:20:41 +0100 | From | Petr Tesarik <> | Subject | Re: [PATCH v2 2/2] kexec: Provide arch_kexec_protect(unprotect)_crashkres() |
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On Thu, 7 Jan 2016 13:08:21 +0800 Xunlei Pang <xlpang@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
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