samples/bpf: xdp_redirect_cpu_user: Do not update bpf maps in option loop

Do not update xdp_redirect_cpu maps running while option loop but
defer it after all available options have been parsed. This is a
preliminary patch to pass the program name we want to attach to the
map entries as a user option

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/95dc46286fd2c609042948e04bb7ae1f5b425538.1594734381.git.lorenzo@kernel.org

samples/bpf/xdp_redirect_cpu_user.c

@@ -681,6 +681,7 @@ int main(int argc, char **argv)
 	int add_cpu = -1;
 	int opt, err;
 	int prog_fd;
+	int *cpu, i;
 	__u32 qsize;
 
 	n_cpus = get_nprocs_conf();
@@ -716,6 +717,13 @@ int main(int argc, char **argv)
 	}
 	mark_cpus_unavailable();
 
+	cpu = malloc(n_cpus * sizeof(int));
+	if (!cpu) {
+		fprintf(stderr, "failed to allocate cpu array\n");
+		return EXIT_FAIL;
+	}
+	memset(cpu, 0, n_cpus * sizeof(int));
+
 	/* Parse commands line args */
 	while ((opt = getopt_long(argc, argv, "hSd:s:p:q:c:xzF",
 				  long_options, &longindex)) != -1) {
@@ -760,8 +768,7 @@ int main(int argc, char **argv)
 					errno, strerror(errno));
 				goto error;
 			}
-			create_cpu_entry(add_cpu, qsize, added_cpus, true);
+			cpu[added_cpus++] = add_cpu;
-			added_cpus++;
 			break;
 		case 'q':
 			qsize = atoi(optarg);
@@ -772,6 +779,7 @@ int main(int argc, char **argv)
 		case 'h':
 		error:
 		default:
+			free(cpu);
 			usage(argv, obj);
 			return EXIT_FAIL_OPTION;
 		}
@@ -784,16 +792,21 @@ int main(int argc, char **argv)
 	if (ifindex == -1) {
 		fprintf(stderr, "ERR: required option --dev missing\n");
 		usage(argv, obj);
-		return EXIT_FAIL_OPTION;
+		err = EXIT_FAIL_OPTION;
+		goto out;
 	}
 	/* Required option */
 	if (add_cpu == -1) {
 		fprintf(stderr, "ERR: required option --cpu missing\n");
 		fprintf(stderr, " Specify multiple --cpu option to add more\n");
 		usage(argv, obj);
-		return EXIT_FAIL_OPTION;
+		err = EXIT_FAIL_OPTION;
+		goto out;
 	}
 
+	for (i = 0; i < added_cpus; i++)
+		create_cpu_entry(cpu[i], qsize, i, true);
+
 	/* Remove XDP program when program is interrupted or killed */
 	signal(SIGINT, int_exit);
 	signal(SIGTERM, int_exit);
@@ -801,27 +814,32 @@ int main(int argc, char **argv)
 	prog = bpf_object__find_program_by_title(obj, prog_name);
 	if (!prog) {
 		fprintf(stderr, "bpf_object__find_program_by_title failed\n");
-		return EXIT_FAIL;
+		err = EXIT_FAIL;
+		goto out;
 	}
 
 	prog_fd = bpf_program__fd(prog);
 	if (prog_fd < 0) {
 		fprintf(stderr, "bpf_program__fd failed\n");
-		return EXIT_FAIL;
+		err = EXIT_FAIL;
+		goto out;
 	}
 
 	if (bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags) < 0) {
 		fprintf(stderr, "link set xdp fd failed\n");
-		return EXIT_FAIL_XDP;
+		err = EXIT_FAIL_XDP;
+		goto out;
 	}
 
 	err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
 	if (err) {
 		printf("can't get prog info - %s\n", strerror(errno));
-		return err;
+		goto out;
 	}
 	prog_id = info.id;
 
 	stats_poll(interval, use_separators, prog_name, stress_mode);
-	return EXIT_OK;
+out:
+	free(cpu);
+	return err;
 }