linux-kernel - Re: [PATCH][next] bpf: replace redundant |= operation with assignmen

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Message-ID: <CAEf4Bzbd2qDmUmVYtX56oz7Cj4+H88LyemSVd3YxCmcPYLg5-Q@mail.gmail.com>
Date: Fri, 1 Nov 2024 12:30:56 -0700
From: Andrii Nakryiko <andrii.nakryiko@...il.com>
To: Colin Ian King <colin.i.king@...il.com>
Cc: Alexei Starovoitov <ast@...nel.org>, Daniel Borkmann <daniel@...earbox.net>, 
	Andrii Nakryiko <andrii@...nel.org>, Martin KaFai Lau <martin.lau@...ux.dev>, 
	Eduard Zingerman <eddyz87@...il.com>, Song Liu <song@...nel.org>, 
	Yonghong Song <yonghong.song@...ux.dev>, John Fastabend <john.fastabend@...il.com>, 
	KP Singh <kpsingh@...nel.org>, Stanislav Fomichev <sdf@...ichev.me>, Hao Luo <haoluo@...gle.com>, 
	Jiri Olsa <jolsa@...nel.org>, bpf@...r.kernel.org, kernel-janitors@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH][next] bpf: replace redundant |= operation with assignmen

On Thu, Oct 31, 2024 at 6:07 AM Colin Ian King <colin.i.king@...il.com> wrote:
>
> The operation msk |= ~0ULL contains a redundant bit-wise or operation
> since all the bits are going to be set to 1, so replace this with
> an assignment since this is more optimal and probably clearer too.
>
> Signed-off-by: Colin Ian King <colin.i.king@...il.com>
> ---
>  kernel/bpf/inode.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
> index 9aaf5124648b..fea07e12601f 100644
> --- a/kernel/bpf/inode.c
> +++ b/kernel/bpf/inode.c
> @@ -914,7 +914,7 @@ static int bpf_parse_param(struct fs_context *fc, struct fs_parameter *param)
>                 str = param->string;
>                 while ((p = strsep(&str, ":"))) {
>                         if (strcmp(p, "any") == 0) {
> -                               msk |= ~0ULL;
> +                               msk = ~0ULL;

This was done for consistency with the other branch. Is there anything
wrong with this code? Doesn't seem so, so I'd like to keep it as is.

pw-bot: cr

>                         } else if (find_btf_enum_const(info.btf, enum_t, enum_pfx, p, &val)) {
>                                 msk |= 1ULL << val;
>                         } else {
> --
> 2.39.5
>