net/smc: support ipv4 mapped ipv6 addr client for smc-r v2

AF_INET6 is not supported for smc-r v2 client before, even if the
ipv6 addr is ipv4 mapped. Thus, when using AF_INET6, smc-r connection
will fallback to tcp, especially for java applications running smc-r.
This patch support ipv4 mapped ipv6 addr client for smc-r v2. Clients
using real global ipv6 addr is still not supported yet.

Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>
Reviewed-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Reviewed-by: D. Wythe <alibuda@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 9e6c69d18581ce6c31d3d357ed2cb29bde6e13a7..19ebff1c2579ff3bbeb92b82af3c7dd81dfbdab0 100644 (file)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1117,7 +1117,10 @@ 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;