netfilter: xtables: change targets to return error code

Part of the transition of done by this semantic patch:
// <smpl>
@ rule1 @
struct xt_target ops;
identifier check;
@@
 ops.checkentry = check;

@@
identifier rule1.check;
@@
 check(...) { <...
-return true;
+return 0;
 ...> }

@@
identifier rule1.check;
@@
 check(...) { <...
-return false;
+return -EINVAL;
 ...> }
// </smpl>

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

net/ipv6/netfilter/ip6t_LOG.c

@@ -457,13 +457,13 @@ static int log_tg6_check(const struct xt_tgchk_param *par)
 
 	if (loginfo->level >= 8) {
 		pr_debug("level %u >= 8\n", loginfo->level);
-		return false;
+		return -EINVAL;
 	}
 	if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
 		pr_debug("prefix not null-terminated\n");
-		return false;
+		return -EINVAL;
 	}
-	return true;
+	return 0;
 }
 
 static struct xt_target log_tg6_reg __read_mostly = {

net/ipv6/netfilter/ip6t_REJECT.c

@@ -220,16 +220,16 @@ static int reject_tg6_check(const struct xt_tgchk_param *par)
 
 	if (rejinfo->with == IP6T_ICMP6_ECHOREPLY) {
 		pr_info("ECHOREPLY is not supported.\n");
-		return false;
+		return -EINVAL;
 	} else if (rejinfo->with == IP6T_TCP_RESET) {
 		/* Must specify that it's a TCP packet */
 		if (e->ipv6.proto != IPPROTO_TCP ||
 		    (e->ipv6.invflags & XT_INV_PROTO)) {
 			pr_info("TCP_RESET illegal for non-tcp\n");
-			return false;
+			return -EINVAL;
 		}
 	}
-	return true;
+	return 0;
 }
 
 static struct xt_target reject_tg6_reg __read_mostly = {