netdev - Re: [PATCH bpf-next] libbpf: remove zc variable as it is not used

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Message-ID: <f3a8ea34-bd70-8ab8-9739-bb086643fa44@fb.com>
Date:   Fri, 16 Aug 2019 15:37:00 +0000
From:   Yonghong Song <yhs@...com>
To:     Magnus Karlsson <magnus.karlsson@...el.com>,
        "bjorn.topel@...el.com" <bjorn.topel@...el.com>,
        "ast@...nel.org" <ast@...nel.org>,
        "daniel@...earbox.net" <daniel@...earbox.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC:     "bpf@...r.kernel.org" <bpf@...r.kernel.org>
Subject: Re: [PATCH bpf-next] libbpf: remove zc variable as it is not used



On 8/16/19 3:26 AM, Magnus Karlsson wrote:
> The zc is not used in the xsk part of libbpf, so let us remove it. Not
> good to have dead code lying around.
> 
> Signed-off-by: Magnus Karlsson <magnus.karlsson@...el.com>
> Reported-by: Yonghong Song <yhs@...com> > ---
>   tools/lib/bpf/xsk.c | 3 ---
>   1 file changed, 3 deletions(-)
> 
> diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
> index 680e630..9687da9 100644
> --- a/tools/lib/bpf/xsk.c
> +++ b/tools/lib/bpf/xsk.c
> @@ -65,7 +65,6 @@ struct xsk_socket {
>   	int xsks_map_fd;
>   	__u32 queue_id;
>   	char ifname[IFNAMSIZ];
> -	bool zc;
>   };
>   
>   struct xsk_nl_info {
> @@ -608,8 +607,6 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname,
>   		goto out_mmap_tx;
>   	}
>   
> -	xsk->zc = opts.flags & XDP_OPTIONS_ZEROCOPY;

Since opts.flags usage is removed. Do you think it makes sense to
remove
         optlen = sizeof(opts);
         err = getsockopt(xsk->fd, SOL_XDP, XDP_OPTIONS, &opts, &optlen);
         if (err) {
                 err = -errno;
                 goto out_mmap_tx;
         }
as well since nobody then uses opts?

> -
>   	if (!(xsk->config.libbpf_flags & XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD)) {
>   		err = xsk_setup_xdp_prog(xsk);
>   		if (err)
>