shaozhengchao <shaozhengchao@xxxxxxxxxx> writes: > -----邮件原件----- > 发件人: Toke Høiland-Jørgensen [mailto:toke@xxxxxxxxxx] > 发送时间: 2022年6月2日 16:55 > 收件人: shaozhengchao <shaozhengchao@xxxxxxxxxx>; bpf@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; ast@xxxxxxxxxx; daniel@xxxxxxxxxxxxx; davem@xxxxxxxxxxxxx; kuba@xxxxxxxxxx; hawk@xxxxxxxxxx; john.fastabend@xxxxxxxxx; andrii@xxxxxxxxxx; kafai@xxxxxx; songliubraving@xxxxxx; yhs@xxxxxx; kpsingh@xxxxxxxxxx > 抄送: weiyongjun (A) <weiyongjun1@xxxxxxxxxx>; shaozhengchao <shaozhengchao@xxxxxxxxxx>; yuehaibing <yuehaibing@xxxxxxxxxx> > 主题: Re: [PATCH v5,bpf-next] samples/bpf: check detach prog exist or not in xdp_fwd > > 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 > > > Hi Toke: > Use 'return prog_fd' instead of 'return errno' first. And Which > position missed one 'return errno'? Ah, no, that's the one I was talking about; I meant "missed one" as in "missed removing one of them", not "a return errno was missing but should be there"; so just changing that one to 'return prog_fd' should and I think we should be good :) -Toke
