Messages in this thread Patch in this message | | | Date | Mon, 14 Nov 2011 13:17:11 -0800 (PST) | From | Andrei Warkentin <> | Subject | Re: [PATCH] include/log2.h: Fix rounddown_pow_of_two(1) |
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----- Original Message ----- > From: "Jesper Juhl" <jj@chaosbits.net> > To: "Andrei Warkentin" <andreiw@vmware.com> > Cc: linux-kernel@vger.kernel.org > Sent: Tuesday, November 8, 2011 2:57:27 PM > Subject: Re: [PATCH] include/log2.h: Fix rounddown_pow_of_two(1) > > On Tue, 8 Nov 2011, Andrei Warkentin wrote: > > > 1 is a power of two, therefore rounddown_pow_of_two(1) should > > return 1. It does > > in case the argument is a variable but in case it's a constant it > > behaves > > wrong and returns 0. Probably nobody ever did it so this was never > > noticed, > > however net/drivers/vmxnet3 with latest GCC does and breaks on > > unicpu systems. > > > > Signed-off-by: Andrei Warkentin <andreiw@vmware.com> > > --- > > include/linux/log2.h | 2 +- > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > diff --git a/include/linux/log2.h b/include/linux/log2.h > > index 25b8086..ccda848 100644 > > --- a/include/linux/log2.h > > +++ b/include/linux/log2.h > > @@ -185,7 +185,7 @@ unsigned long __rounddown_pow_of_two(unsigned > > long n) > > #define rounddown_pow_of_two(n) \ > > ( \ > > __builtin_constant_p(n) ? ( \ > > - (n == 1) ? 0 : \ > > + (n == 1) ? 1 : \ > > (1UL << ilog2(n))) : \ > > __rounddown_pow_of_two(n) \ > > ) > > > > For what it's worth; looks good to me.
Is that an Acked-by or a Reviewed-by?
Thanks, A
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