diff --git a/cmd/zpool/zpool_main.c b/cmd/zpool/zpool_main.c
index 95d0c279a7..93d6a18981 100644
--- a/cmd/zpool/zpool_main.c
+++ b/cmd/zpool/zpool_main.c
@@ -10328,29 +10328,27 @@ zpool_do_set(int argc, char **argv)
 	argc -= 2;
 	argv += 2;
 
-	if (are_vdevs_in_pool(argc, argv, NULL, &cb.cb_vdevs)) {
-		/* Argument is a vdev */
-		cb.cb_vdevs.cb_names = argv;
-		cb.cb_vdevs.cb_names_count = 1;
-		cb.cb_type = ZFS_TYPE_VDEV;
-		argc = 0; /* No pools to process */
-	} else if (are_all_pools(1, argv)) {
-		/* The first arg is a pool name */
-		if (are_vdevs_in_pool(argc - 1, argv + 1, argv[0],
-		    &cb.cb_vdevs)) {
-			/* 2nd argument is a vdev */
-			cb.cb_vdevs.cb_names = argv + 1;
-			cb.cb_vdevs.cb_names_count = 1;
-			cb.cb_type = ZFS_TYPE_VDEV;
-			argc = 1; /* One pool to process */
-		} else if (argc > 1) {
-			(void) fprintf(stderr,
-			    gettext("too many pool names\n"));
-			usage(B_FALSE);
-		}
+	/* argv[0] is pool name */
+	if (!is_pool(argv[0])) {
+		(void) fprintf(stderr,
+		    gettext("cannot open '%s': is not a pool\n"), argv[0]);
+		return (EINVAL);
 	}
 
-	error = for_each_pool(argc, argv, B_TRUE, NULL, ZFS_TYPE_POOL,
+	/* argv[1], when supplied, is vdev name */
+	if (argc == 2) {
+		if (!are_vdevs_in_pool(1, argv + 1, argv[0], &cb.cb_vdevs)) {
+			(void) fprintf(stderr, gettext(
+			    "cannot find '%s' in '%s': device not in pool\n"),
+			    argv[1], argv[0]);
+			return (EINVAL);
+		}
+		cb.cb_vdevs.cb_names = argv + 1;
+		cb.cb_vdevs.cb_names_count = 1;
+		cb.cb_type = ZFS_TYPE_VDEV;
+	}
+
+	error = for_each_pool(1, argv, B_TRUE, NULL, ZFS_TYPE_POOL,
 	    B_FALSE, set_callback, &cb);
 
 	return (error);