net/smc: handle sockopts forcing fallback

Several TCP sockopts do not work for SMC. One example are the
TCP_FASTOPEN sockopts, since SMC-connection setup is based on the TCP
three-way-handshake.
If the SMC socket is still in state SMC_INIT, such sockopts trigger
fallback to TCP. Otherwise an error is returned.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 4470501..d274be7 100644 (file)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -391,6 +391,9 @@ static int smc_connect_rdma(struct smc_sock *smc)
 
        sock_hold(&smc->sk); /* sock put in passive closing */
 
+       if (smc->use_fallback)
+               goto out_connected;
+
        if (!tcp_sk(smc->clcsock->sk)->syn_smc) {
                /* peer has not signalled SMC-capability */
                smc->use_fallback = true;
@@ -790,6 +793,9 @@ static void smc_listen_work(struct work_struct *work)
        int rc = 0;
        u8 ibport;
 
+       if (new_smc->use_fallback)
+               goto out_connected;
+
        /* check if peer is smc capable */
        if (!tcp_sk(newclcsock->sk)->syn_smc) {
                new_smc->use_fallback = true;
@@ -968,7 +974,7 @@ static void smc_tcp_listen_work(struct work_struct *work)
                        continue;
 
                new_smc->listen_smc = lsmc;
-               new_smc->use_fallback = false; /* assume rdma capability first*/
+               new_smc->use_fallback = lsmc->use_fallback;
                sock_hold(lsk); /* sock_put in smc_listen_work */
                INIT_WORK(&new_smc->smc_listen_work, smc_listen_work);
                smc_copy_sock_settings_to_smc(new_smc);
@@ -1004,7 +1010,8 @@ static int smc_listen(struct socket *sock, int backlog)
         * them to the clc socket -- copy smc socket options to clc socket
         */
        smc_copy_sock_settings_to_clc(smc);
-       tcp_sk(smc->clcsock->sk)->syn_smc = 1;
+       if (!smc->use_fallback)
+               tcp_sk(smc->clcsock->sk)->syn_smc = 1;
 
        rc = kernel_listen(smc->clcsock, backlog);
        if (rc)
@@ -1097,6 +1104,16 @@ static int smc_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
            (sk->sk_state != SMC_APPCLOSEWAIT1) &&
            (sk->sk_state != SMC_INIT))
                goto out;
+
+       if (msg->msg_flags & MSG_FASTOPEN) {
+               if (sk->sk_state == SMC_INIT) {
+                       smc->use_fallback = true;
+               } else {
+                       rc = -EINVAL;
+                       goto out;
+               }
+       }
+
        if (smc->use_fallback)
                rc = smc->clcsock->ops->sendmsg(smc->clcsock, msg, len);
        else
@@ -1274,14 +1291,43 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
 {
        struct sock *sk = sock->sk;
        struct smc_sock *smc;
+       int rc;
 
        smc = smc_sk(sk);
 
        /* generic setsockopts reaching us here always apply to the
         * CLC socket
         */
-       return smc->clcsock->ops->setsockopt(smc->clcsock, level, optname,
-                                            optval, optlen);
+       rc = smc->clcsock->ops->setsockopt(smc->clcsock, level, optname,
+                                          optval, optlen);
+       if (smc->clcsock->sk->sk_err) {
+               sk->sk_err = smc->clcsock->sk->sk_err;
+               sk->sk_error_report(sk);
+       }
+       if (rc)
+               return rc;
+
+       lock_sock(sk);
+       switch (optname) {
+       case TCP_ULP:
+       case TCP_FASTOPEN:
+       case TCP_FASTOPEN_CONNECT:
+       case TCP_FASTOPEN_KEY:
+       case TCP_FASTOPEN_NO_COOKIE:
+               /* option not supported by SMC */
+               if (sk->sk_state == SMC_INIT) {
+                       smc->use_fallback = true;
+               } else {
+                       if (!smc->use_fallback)
+                               rc = -EINVAL;
+               }
+               break;
+       default:
+               break;
+       }
+       release_sock(sk);
+
+       return rc;
 }
 
 static int smc_getsockopt(struct socket *sock, int level, int optname,