linux-kernel - Re: [PATCH] bitops: simplify get_count_order

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Date:   Mon, 25 May 2020 18:32:16 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Wei Yang <richard.weiyang@...il.com>,
        Jesse Brandeburg <jesse.brandeburg@...el.com>
Cc:     akpm@...ux-foundation.org, christian.brauner@...ntu.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] bitops: simplify get_count_order_long()

On Mon, May 25, 2020 at 02:43:12PM +0000, Wei Yang wrote:
> On Mon, May 25, 2020 at 12:14:58PM +0300, Andy Shevchenko wrote:
> >On Sun, May 24, 2020 at 12:35:51PM +0000, Wei Yang wrote:
> >> These two cases could be unified into one.
> >
> >Care to provide a test case which supports your change?
> >
> 
> Hmm.. where should I put the test? tools/testing/selftests/ ?

I guess into test_bitops.c [1]? I though it eventually should make kernel, but I don't see it.

Andrew, can you apply that or do you need Jesse to resend?

[1]: https://lore.kernel.org/lkml/20200310221747.2848474-2-jesse.brandeburg@intel.com/

> 
> >> Signed-off-by: Wei Yang <richard.weiyang@...il.com>
> >> ---
> >>  include/linux/bitops.h | 5 +----
> >>  1 file changed, 1 insertion(+), 4 deletions(-)
> >> 
> >> diff --git a/include/linux/bitops.h b/include/linux/bitops.h
> >> index 9acf654f0b19..5b5609e81a84 100644
> >> --- a/include/linux/bitops.h
> >> +++ b/include/linux/bitops.h
> >> @@ -206,10 +206,7 @@ static inline int get_count_order_long(unsigned long l)
> >>  {
> >>  	if (l == 0UL)
> >>  		return -1;
> >> -	else if (l & (l - 1UL))
> >> -		return (int)fls_long(l);
> >> -	else
> >> -		return (int)fls_long(l) - 1;
> >> +	return (int)fls_long(--l);
> >>  }
> >
> >-- 
> >With Best Regards,
> >Andy Shevchenko
> >
> 
> -- 
> Wei Yang
> Help you, Help me

-- 
With Best Regards,
Andy Shevchenko