bpf: offload: make bpf_offload_dev_match() reject host+host case

Daniel suggests it would be more logical for bpf_offload_dev_match()
to return false is either the program or the map are not offloaded,
rather than treating the both not offloaded case as a "matching
CPU/host device".

This makes no functional difference today, since verifier only calls
bpf_offload_dev_match() when one of the objects is offloaded.
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

kernel/bpf/offload.c

@@ -395,10 +395,8 @@ bool bpf_offload_dev_match(struct bpf_prog *prog, struct bpf_map *map)
 	struct bpf_prog_offload *offload;
 	bool ret;
 
-	if (!!bpf_prog_is_dev_bound(prog->aux) != !!bpf_map_is_dev_bound(map))
+	if (!bpf_prog_is_dev_bound(prog->aux) || !bpf_map_is_dev_bound(map))
 		return false;
-	if (!bpf_prog_is_dev_bound(prog->aux))
-		return true;
 
 	down_read(&bpf_devs_lock);
 	offload = prog->aux->offload;