Merge: [s390] net/smc: AF_INET6 is not supported for smc-r v2 client

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-10/-/merge_requests/404

JIRA: https://issues.redhat.com/browse/RHEL-79809

commits;
```
c12b270
```

Signed-off-by: Mete Durlu <mdurlu@redhat.com>

Approved-by: Steve Best <sbest@redhat.com>
Approved-by: Tony Camuso <tcamuso@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Julio Faracco <jfaracco@redhat.com>

Author: jcfaracco

net/smc/af_smc.c

@@ -1116,7 +1116,10 @@ static int smc_find_proposal_devices(struct smc_sock *smc,
 	ini->check_smcrv2 = true;
 	ini->smcrv2.saddr = smc->clcsock->sk->sk_rcv_saddr;
 	if (!(ini->smcr_version & SMC_V2) ||
-	    smc->clcsock->sk->sk_family != AF_INET ||
+#if IS_ENABLED(CONFIG_IPV6)
+	    (smc->clcsock->sk->sk_family == AF_INET6 &&
+	     !ipv6_addr_v4mapped(&smc->clcsock->sk->sk_v6_rcv_saddr)) ||
+#endif
 	    !smc_clc_ueid_count() ||
 	    smc_find_rdma_device(smc, ini))
 		ini->smcr_version &= ~SMC_V2;