net/smc: handle sockopt TCP_DEFER_ACCEPT

If sockopt TCP_DEFER_ACCEPT is set, the accept is delayed till
data is available.

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

4 files changed, 31 insertions, 2 deletions

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 9d8b381281e3..20aa4175b9f8 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1044,6 +1044,7 @@ static int smc_accept(struct socket *sock, struct socket *new_sock,
 
         if (lsmc->sk.sk_state != SMC_LISTEN) {
                 rc = -EINVAL;
+                release_sock(sk);
                 goto out;
         }
 
@@ -1071,9 +1072,29 @@ static int smc_accept(struct socket *sock, struct socket *new_sock,
 
         if (!rc)
                 rc = sock_error(nsk);
+        release_sock(sk);
+        if (rc)
+                goto out;
+
+        if (lsmc->sockopt_defer_accept && !(flags & O_NONBLOCK)) {
+                /* wait till data arrives on the socket */
+                timeo = msecs_to_jiffies(lsmc->sockopt_defer_accept *
+                                                                MSEC_PER_SEC);
+                if (smc_sk(nsk)->use_fallback) {
+                        struct sock *clcsk = smc_sk(nsk)->clcsock->sk;
+
+                        lock_sock(clcsk);
+                        if (skb_queue_empty(&clcsk->sk_receive_queue))
+                                sk_wait_data(clcsk, &timeo, NULL);
+                        release_sock(clcsk);
+                } else if (!atomic_read(&smc_sk(nsk)->conn.bytes_to_rcv)) {
+                        lock_sock(nsk);
+                        smc_rx_wait_data(smc_sk(nsk), &timeo);
+                        release_sock(nsk);
+                }
+        }
 
 out:
-        release_sock(sk);
         sock_put(sk); /* sock_hold above */
         return rc;
 }
@@ -1340,6 +1361,9 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
                                                  0);
                 }
                 break;
+        case TCP_DEFER_ACCEPT:
+                smc->sockopt_defer_accept = val;
+                break;
         default:
                 break;
         }
diff --git a/net/smc/smc.h b/net/smc/smc.h
index e4829a2f46ba..2405e889b93d 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -180,6 +180,10 @@ struct smc_sock {				/* smc sock container */
         struct list_head        accept_q;       /* sockets to be accepted */
         spinlock_t              accept_q_lock;  /* protects accept_q */
         bool                    use_fallback;   /* fallback to tcp */
+        int                     sockopt_defer_accept;
+                                                /* sockopt TCP_DEFER_ACCEPT
+                                                 * value
+                                                 */
         u8                      wait_close_tx_prepared : 1;
                                                 /* shutdown wr or close
                                                  * started, waiting for unsent
diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
index eff4e0d0bb31..af851d8df1f8 100644
--- a/net/smc/smc_rx.c
+++ b/net/smc/smc_rx.c
@@ -51,7 +51,7 @@ static void smc_rx_data_ready(struct sock *sk)
  * 1 if at least 1 byte available in rcvbuf or if socket error/shutdown.
  * 0 otherwise (nothing in rcvbuf nor timeout, e.g. interrupted).
  */
-static int smc_rx_wait_data(struct smc_sock *smc, long *timeo)
+int smc_rx_wait_data(struct smc_sock *smc, long *timeo)
 {
         DEFINE_WAIT_FUNC(wait, woken_wake_function);
         struct smc_connection *conn = &smc->conn;
diff --git a/net/smc/smc_rx.h b/net/smc/smc_rx.h
index 3a32b59bf06c..0b75a6b470e6 100644
--- a/net/smc/smc_rx.h
+++ b/net/smc/smc_rx.h
@@ -20,5 +20,6 @@
 void smc_rx_init(struct smc_sock *smc);
 int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, size_t len,
                    int flags);
+int smc_rx_wait_data(struct smc_sock *smc, long *timeo);
 
 #endif /* SMC_RX_H */