Re: [PATCH bpf-next v3 1/4] bpftool: Set BPF_F_XDP_DEV_BOUND_ONLY flag non-destructively

When setting the XDP hints ifname, bpftool would set the
BPF_F_XDP_DEV_BOUND_ONLY without looking at the existing program flags,
overriding any other flag values. This was always a destructive action,
but after we change libbpf to carry the frags section flag in
prog_flags, this can impact bpftool loading of XDP frags programs.

Change the flag setting to be non-destructive by OR'ing it with the
existing flags.

Fixes: f46392ee3dec ("bpftool: Specify XDP Hints ifname when loading program")
Reviewed-by: Larysa Zaremba <redacted>
Signed-off-by: Toke Høiland-Jørgensen <redacted>
---
 tools/bpf/bpftool/prog.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index a9f730d407a9..8c2f9255b36d 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c

@@ -1769,7 +1769,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
                }

                if (prog_type == BPF_PROG_TYPE_XDP && xdpmeta_ifindex) {
-                       bpf_program__set_flags(pos, BPF_F_XDP_DEV_BOUND_ONLY);
+                       bpf_program__set_flags(pos, bpf_program__flags(pos) | BPF_F_XDP_DEV_BOUND_ONLY);