1 files changed, 32 insertions, 6 deletions

diff --git a/samples/bpf/xdp_adjust_tail_user.c b/samples/bpf/xdp_adjust_tail_user.c
index 3042ce37dae8..07e1b9269e49 100644
--- a/samples/bpf/xdp_adjust_tail_user.c
+++ b/samples/bpf/xdp_adjust_tail_user.c
@@ -24,12 +24,25 @@
 #define STATS_INTERVAL_S 2U
 
 static int ifindex = -1;
-static __u32 xdp_flags;
+static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
+static __u32 prog_id;
 
 static void int_exit(int sig)
 {
-	if (ifindex > -1)
-		bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
+	__u32 curr_prog_id = 0;
+
+	if (ifindex > -1) {
+		if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) {
+			printf("bpf_get_link_xdp_id failed\n");
+			exit(1);
+		}
+		if (prog_id == curr_prog_id)
+			bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
+		else if (!curr_prog_id)
+			printf("couldn't find a prog id on a given iface\n");
+		else
+			printf("program on interface changed, not removing\n");
+	}
 	exit(0);
 }
 
@@ -60,6 +73,7 @@ static void usage(const char *cmd)
 	printf("    -T <stop-after-X-seconds> Default: 0 (forever)\n");
 	printf("    -S use skb-mode\n");
 	printf("    -N enforce native mode\n");
+	printf("    -F force loading prog\n");
 	printf("    -h Display this help\n");
 }
 
@@ -70,12 +84,15 @@ int main(int argc, char **argv)
 		.prog_type	= BPF_PROG_TYPE_XDP,
 	};
 	unsigned char opt_flags[256] = {};
+	const char *optstr = "i:T:SNFh";
+	struct bpf_prog_info info = {};
+	__u32 info_len = sizeof(info);
 	unsigned int kill_after_s = 0;
-	const char *optstr = "i:T:SNh";
 	int i, prog_fd, map_fd, opt;
 	struct bpf_object *obj;
 	struct bpf_map *map;
 	char filename[256];
+	int err;
 
 	for (i = 0; i < strlen(optstr); i++)
 		if (optstr[i] != 'h' && 'a' <= optstr[i] && optstr[i] <= 'z')
@@ -96,6 +113,9 @@ int main(int argc, char **argv)
 		case 'N':
 			xdp_flags |= XDP_FLAGS_DRV_MODE;
 			break;
+		case 'F':
+			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
+			break;
 		default:
 			usage(argv[0]);
 			return 1;
@@ -142,9 +162,15 @@ int main(int argc, char **argv)
 		return 1;
 	}
 
-	poll_stats(map_fd, kill_after_s);
+	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 1;
+	}
+	prog_id = info.id;
 
-	bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
+	poll_stats(map_fd, kill_after_s);
+	int_exit(0);
 
 	return 0;
 }