linux-kernel - Re: [PATCH] libbpf: Fix is_pow_of

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Message-ID: <20220619171248.GC3362@bug>
Date:   Sun, 19 Jun 2022 19:12:48 +0200
From:   Pavel Machek <pavel@....cz>
To:     Ian Rogers <irogers@...gle.com>
Cc:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>, netdev@...r.kernel.org,
        bpf@...r.kernel.org, linux-kernel@...r.kernel.org,
        Yuze Chi <chiyuze@...gle.com>
Subject: Re: [PATCH] libbpf: Fix is_pow_of_2

Hi!

> From: Yuze Chi <chiyuze@...gle.com>
> 
> +++ b/tools/lib/bpf/libbpf.c
> @@ -4956,7 +4956,7 @@ static void bpf_map__destroy(struct bpf_map *map);
>  
>  static bool is_pow_of_2(size_t x)
>  {
> -	return x && (x & (x - 1));
> +	return x && !(x & (x - 1));
>  }

I'm pretty sure we have this test in macro in includes somewhere... should we use
that instead?
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html