Zhengchao Shao <shaozhengchao@xxxxxxxxxx> writes:
> Before detach the prog, we should check detach prog exist or not.
>
> Signed-off-by: Zhengchao Shao <shaozhengchao@xxxxxxxxxx>
You missed one 'return errno', see below:
> ---
> samples/bpf/xdp_fwd_user.c | 55 +++++++++++++++++++++++++++++++++-----
> 1 file changed, 49 insertions(+), 6 deletions(-)
>
> diff --git a/samples/bpf/xdp_fwd_user.c b/samples/bpf/xdp_fwd_user.c
> index 1828487bae9a..d321e6aa9364 100644
> --- a/samples/bpf/xdp_fwd_user.c
> +++ b/samples/bpf/xdp_fwd_user.c
> @@ -47,17 +47,60 @@ static int do_attach(int idx, int prog_fd, int map_fd, const char *name)
> return err;
> }
>
> -static int do_detach(int idx, const char *name)
> +static int do_detach(int ifindex, const char *ifname, const char *app_name)
> {
> - int err;
> + LIBBPF_OPTS(bpf_xdp_attach_opts, opts);
> + struct bpf_prog_info prog_info = {};
> + char prog_name[BPF_OBJ_NAME_LEN];
> + __u32 info_len, curr_prog_id;
> + int prog_fd;
> + int err = 1;
> +
> + if (bpf_xdp_query_id(ifindex, xdp_flags, &curr_prog_id)) {
> + printf("ERROR: bpf_xdp_query_id failed (%s)\n",
> + strerror(errno));
> + return err;
> + }
>
> - err = bpf_xdp_detach(idx, xdp_flags, NULL);
> - if (err < 0)
> - printf("ERROR: failed to detach program from %s\n", name);
> + if (!curr_prog_id) {
> + printf("ERROR: flags(0x%x) xdp prog is not attached to %s\n",
> + xdp_flags, ifname);
> + return err;
> + }
>
> + info_len = sizeof(prog_info);
> + prog_fd = bpf_prog_get_fd_by_id(curr_prog_id);
> + if (prog_fd < 0) {
> + printf("ERROR: bpf_prog_get_fd_by_id failed (%s)\n",
> + strerror(errno));
> + return errno;
This should just be 'return prog_fd' to propagate the error...
-Toke
