netfilter: conntrack: clean up returns in nf_conntrack_log_invalid_sysctl()

JIRA: https://issues.redhat.com/browse/RHEL-115582
Upstream Status: commit f54186d

commit f54186d
Author: Dan Carpenter <dan.carpenter@linaro.org>
Date:   Mon Aug 4 13:35:15 2025 +0300

    netfilter: conntrack: clean up returns in nf_conntrack_log_invalid_sysctl()

    Smatch complains that these look like error paths with missing error
    codes, especially the one where we return if nf_log_is_registered() is
    true:

        net/netfilter/nf_conntrack_standalone.c:575 nf_conntrack_log_invalid_sysctl()
        warn: missing error code? 'ret'

    In fact, all these return zero deliberately.  Change them to return a
    literal instead which helps readability as well as silencing the warning.

    Fixes: e89a680 ("netfilter: load nf_log_syslog on enabling nf_conntrack_log_invalid")
    Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
    Acked-by: Lance Yang <lance.yang@linux.dev>
    Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Signed-off-by: Florian Westphal <fwestpha@redhat.com>

Author: fw-strlen

net/netfilter/nf_conntrack_standalone.c

@@ -574,16 +574,16 @@ nf_conntrack_log_invalid_sysctl(const struct ctl_table *table, int write,
 		return ret;
 
 	if (*(u8 *)table->data == 0)
-		return ret;
+		return 0;
 
 	/* Load nf_log_syslog only if no logger is currently registered */
 	for (i = 0; i < NFPROTO_NUMPROTO; i++) {
 		if (nf_log_is_registered(i))
-			return ret;
+			return 0;
 	}
 	request_module("%s", "nf_log_syslog");
 
-	return ret;
+	return 0;
 }
 
 static struct ctl_table_header *nf_ct_netfilter_header;