[PATCH net-next v3 2/2] net/smc: support ipv4 mapped ipv6 addr client for smc-r v2

[Guangguan Wang <guangguan.wang@linux.alibaba.com>]

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>
---
 net/smc/af_smc.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 9d76e902fd77..c3f9c0457418 100644
--- a/net/smc/af_smc.c
+++ b/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;
-- 
2.24.3 (Apple Git-128)