[PATCH V2 net 1/1] net/smc: simplify wait when closing listen socket

[Ursula Braun]

Closing of a listen socket wakes up kernel_accept() of
smc_tcp_listen_worker(), and then has to wait till smc_tcp_listen_worker()
gives up the internal clcsock. The wait logic introduced with
commit 127f49705823 ("net/smc: release clcsock from tcp_listen_worker")
might wait longer than necessary. This patch implements the idea to
implement the wait just with flush_work(), and gets rid of the extra
smc_close_wait_listen_clcsock() function.

Fixes: 127f49705823 ("net/smc: release clcsock from tcp_listen_worker")
Reported-by: Hans Wippel <hwip...@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubr...@linux.vnet.ibm.com>
---
 net/smc/af_smc.c    |  4 ----
 net/smc/smc_close.c | 25 +++----------------------
 2 files changed, 3 insertions(+), 26 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 8cc97834d4f6..1e0d780855c3 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -978,10 +978,6 @@ static void smc_tcp_listen_work(struct work_struct *work)
                lsmc->clcsock = NULL;
        }
        release_sock(lsk);
-       /* no more listening, wake up smc_close_wait_listen_clcsock and
-        * accept
-        */
-       lsk->sk_state_change(lsk);
        sock_put(&lsmc->sk); /* sock_hold in smc_listen */
 }
 
diff --git a/net/smc/smc_close.c b/net/smc/smc_close.c
index e339c0186dcf..fa41d9881741 100644
--- a/net/smc/smc_close.c
+++ b/net/smc/smc_close.c
@@ -30,27 +30,6 @@ static void smc_close_cleanup_listen(struct sock *parent)
                smc_close_non_accepted(sk);
 }
 
-static void smc_close_wait_listen_clcsock(struct smc_sock *smc)
-{
-       DEFINE_WAIT_FUNC(wait, woken_wake_function);
-       struct sock *sk = &smc->sk;
-       signed long timeout;
-
-       timeout = SMC_CLOSE_WAIT_LISTEN_CLCSOCK_TIME;
-       add_wait_queue(sk_sleep(sk), &wait);
-       do {
-               release_sock(sk);
-               if (smc->clcsock)
-                       timeout = wait_woken(&wait, TASK_UNINTERRUPTIBLE,
-                                            timeout);
-               sched_annotate_sleep();
-               lock_sock(sk);
-               if (!smc->clcsock)
-                       break;
-       } while (timeout);
-       remove_wait_queue(sk_sleep(sk), &wait);
-}
-
 /* wait for sndbuf data being transmitted */
 static void smc_close_stream_wait(struct smc_sock *smc, long timeout)
 {
@@ -204,9 +183,11 @@ int smc_close_active(struct smc_sock *smc)
                        rc = kernel_sock_shutdown(smc->clcsock, SHUT_RDWR);
                        /* wake up kernel_accept of smc_tcp_listen_worker */
                        smc->clcsock->sk->sk_data_ready(smc->clcsock->sk);
-                       smc_close_wait_listen_clcsock(smc);
                }
                smc_close_cleanup_listen(sk);
+               release_sock(sk);
+               flush_work(&smc->tcp_listen_work);
+               lock_sock(sk);
                break;
        case SMC_ACTIVE:
                smc_close_stream_wait(smc, timeout);
-- 
2.13.5