From: Zvi Effron <zeffron@riotgames.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: Ian Rogers <irogers@google.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org, Yuze Chi <chiyuze@google.com>
Subject: Re: [PATCH] libbpf: Fix is_pow_of_2
Date: Tue, 21 Jun 2022 18:03:27 -0500 [thread overview]
Message-ID: <CAC1LvL0rZcEHe_ZHDcB38XD49FmdURg4+yKHP0O=J7=4Xx8M3Q@mail.gmail.com> (raw)
In-Reply-To: <20220619171248.GC3362@bug>
On Sun, Jun 19, 2022 at 12:13 PM Pavel Machek <pavel@ucw.cz> wrote:
>
> Hi!
>
> > From: Yuze Chi <chiyuze@google.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?
I went looking for a macro that provided this check and could not find one. I
did find the inlined static function is_power_of_2 in log2.h, though, that we
could use.
> Pavel
> --
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2022-06-21 23:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-03 4:17 [PATCH] libbpf: Fix is_pow_of_2 Ian Rogers
2022-06-03 4:31 ` Zvi Effron
2022-06-03 5:33 ` Andrii Nakryiko
2022-06-03 5:35 ` Andrii Nakryiko
2022-06-19 17:12 ` Pavel Machek
2022-06-21 23:03 ` Zvi Effron [this message]
2022-06-22 0:20 ` Tiezhu Yang
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