Messages in this thread | | | From | Andy Shevchenko <> | Date | Thu, 26 Jul 2018 17:00:39 +0300 | Subject | Re: [PATCH] linux/bitmap.h: fix BITMAP_LAST_WORD_MASK |
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On Thu, Jul 26, 2018 at 1:08 PM, Wei Wang <wei.w.wang@intel.com> wrote: > On 07/26/2018 04:48 PM, Andy Shevchenko wrote: >> >> On Thu, Jul 26, 2018 at 11:07 AM, Wei Wang <wei.w.wang@intel.com> wrote: >>> >>> The existing BITMAP_LAST_WORD_MASK macro returns 0xffffffff if nbits is >>> 0. This patch changes the macro to return 0 when there is no bit needs to >>> be masked. >>> >> Can you provide a practical example of what's going wrong before this >> patch applied? >> > > The reason of making this patch is that I saw some other software which > ports this function and has possibilities to fall into bugs with usages > which pass 0 to the macro.
No problems in the kernel, right?
> So I wonder if it would be necessary to make such > changes in case we would get a similar bug. Or adding something to explain > that "0" is not applicable to this macro as a reminder to people who would > use it.
Comment can be added, yes.
-- With Best Regards, Andy Shevchenko
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