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References: <20220510154750.212913-1-yury.norov@gmail.com> <20220510154750.212913-8-yury.norov@gmail.com>
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From:   Anup Patel <anup@brainfault.org>
Date:   Tue, 10 May 2022 22:01:30 +0530
Message-ID: <CAAhSdy0=g1pp+VgV2=1-3t_u32nX6xx=zmMuVQBd-zyFtQ983A@mail.gmail.com>
Subject: Re: [PATCH 07/22] risc-v: replace bitmap_weight with bitmap_empty in riscv_fill_hwcap()
To:     Yury Norov <yury.norov@gmail.com>
Cc:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        David Laight <David.Laight@aculab.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Joe Perches <joe@perches.com>,
        Julia Lawall <Julia.Lawall@inria.fr>,
        =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= <mirq-linux@rere.qmqm.pl>,
        Nicholas Piggin <npiggin@gmail.com>,
        Nicolas Palix <nicolas.palix@imag.fr>,
        Peter Zijlstra <peterz@infradead.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Matti Vaittinen <Matti.Vaittinen@fi.rohmeurope.com>,
        "linux-kernel@vger.kernel.org List" <linux-kernel@vger.kernel.org>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Atish Patra <atishp@atishpatra.org>,
        Jisheng Zhang <jszhang@kernel.org>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Tsukasa OI <research_trasio@irq.a4lg.com>,
        linux-riscv <linux-riscv@lists.infradead.org>
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On Tue, May 10, 2022 at 9:18 PM Yury Norov <yury.norov@gmail.com> wrote:
>
> bitmap_empty() is better than bitmap_weight() because it may return
> earlier, and improves on readability.
>
> CC: Albert Ou <aou@eecs.berkeley.edu>
> CC: Anup Patel <anup@brainfault.org>
> CC: Atish Patra <atishp@atishpatra.org>
> CC: Jisheng Zhang <jszhang@kernel.org>
> CC: Palmer Dabbelt <palmer@dabbelt.com>
> CC: Paul Walmsley <paul.walmsley@sifive.com>
> CC: Tsukasa OI <research_trasio@irq.a4lg.com>
> CC: linux-riscv@lists.infradead.org
> CC: linux-kernel@vger.kernel.org
> Signed-off-by: Yury Norov <yury.norov@gmail.com>

Looks good to me.

Reviewed-by: Anup Patel <anup@brainfault.org>

Regards,
Anup

> ---
>  arch/riscv/kernel/cpufeature.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 1b2d42d7f589..f0298d756f66 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -206,11 +206,10 @@ void __init riscv_fill_hwcap(void)
>                 else
>                         elf_hwcap = this_hwcap;
>
> -               if (bitmap_weight(riscv_isa, RISCV_ISA_EXT_MAX))
> -                       bitmap_and(riscv_isa, riscv_isa, this_isa, RISCV_ISA_EXT_MAX);
> -               else
> +               if (bitmap_empty(riscv_isa, RISCV_ISA_EXT_MAX))
>                         bitmap_copy(riscv_isa, this_isa, RISCV_ISA_EXT_MAX);
> -
> +               else
> +                       bitmap_and(riscv_isa, riscv_isa, this_isa, RISCV_ISA_EXT_MAX);
>         }
>
>         /* We don't support systems with F but without D, so mask those out
> --
> 2.32.0
>