[PATCH net-next 07/10] net/smc: guarantee ConnClosed send after shutdown SHUT_WR

Ursula Braun
2017-04-10T12:58:02Z

State SMC_CLOSED should be reached only, if ConnClosed has been sent to
the peer. If ConnClosed is received from the peer, a socket with
shutdown SHUT_WR done, switches errorneously to state SMC_CLOSED, which
means the peer socket is dangling. The local SMC socket is supposed to
switch to state APPFINCLOSEWAIT to make sure smc_close_final() is called
during socket close.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
---
net/smc/smc_close.c | 36 +++++++++++++++++++++++++-----------
1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/net/smc/smc_close.c b/net/smc/smc_close.c
index 388503b..9070720b 100644
--- a/net/smc/smc_close.c
+++ b/net/smc/smc_close.c
@@ -164,6 +164,12 @@ void smc_close_active_abort(struct smc_sock *smc)
smc->sk.sk_state_change(&smc->sk);
}

+static inline bool smc_close_sent_any_close(struct smc_connection *conn)
+{
+ return conn->local_tx_ctrl.conn_state_flags.peer_conn_abort ||
+ conn->local_tx_ctrl.conn_state_flags.peer_conn_closed;
+}
+
int smc_close_active(struct smc_sock *smc)
{
struct smc_cdc_conn_state_flags *txflags =
@@ -217,7 +223,7 @@ int smc_close_active(struct smc_sock *smc)
case SMC_APPFINCLOSEWAIT:
/* socket already shutdown wr or both (active close) */
if (txflags->peer_done_writing &&
- !txflags->peer_conn_closed) {
+ !smc_close_sent_any_close(conn)) {
/* just shutdown wr done, send close request */
rc = smc_close_final(conn);
}
@@ -247,6 +253,13 @@ int smc_close_active(struct smc_sock *smc)
break;
case SMC_PEERCLOSEWAIT1:
case SMC_PEERCLOSEWAIT2:
+ if (txflags->peer_done_writing &&
+ !smc_close_sent_any_close(conn)) {
+ /* just shutdown wr done, send close request */
+ rc = smc_close_final(conn);
+ }
+ /* peer sending PeerConnectionClosed will cause transition */
+ break;
case SMC_PEERFINCLOSEWAIT:
/* peer sending PeerConnectionClosed will cause transition */
break;
@@ -284,7 +297,7 @@ static void smc_close_passive_abort_received(struct smc_sock *smc)
case SMC_PEERCLOSEWAIT1:
case SMC_PEERCLOSEWAIT2:
if (txflags->peer_done_writing &&
- !txflags->peer_conn_closed) {
+ !smc_close_sent_any_close(&smc->conn)) {
/* just shutdown, but not yet closed locally */
smc_close_abort(&smc->conn);
sk->sk_state = SMC_PROCESSABORT;
@@ -335,7 +348,7 @@ static void smc_close_passive_work(struct work_struct *work)
case SMC_INIT:
if (atomic_read(&smc->conn.bytes_to_rcv) ||
(rxflags->peer_done_writing &&
- !rxflags->peer_conn_closed))
+ !smc_cdc_rxed_any_close(conn)))
sk->sk_state = SMC_APPCLOSEWAIT1;
else
sk->sk_state = SMC_CLOSED;
@@ -352,7 +365,7 @@ static void smc_close_passive_work(struct work_struct *work)
if (!smc_cdc_rxed_any_close(&smc->conn))
break;
if (sock_flag(sk, SOCK_DEAD) &&
- (sk->sk_shutdown == SHUTDOWN_MASK)) {
+ smc_close_sent_any_close(conn)) {
/* smc_release has already been called locally */
sk->sk_state = SMC_CLOSED;
} else {
@@ -371,16 +384,17 @@ static void smc_close_passive_work(struct work_struct *work)
}

wakeup:
- if (old_state != sk->sk_state)
- sk->sk_state_change(sk);
sk->sk_data_ready(sk); /* wakeup blocked rcvbuf consumers */
sk->sk_write_space(sk); /* wakeup blocked sndbuf producers */

- if ((sk->sk_state == SMC_CLOSED) &&
- (sock_flag(sk, SOCK_DEAD) || !sk->sk_socket)) {
- smc_conn_free(&smc->conn);
- schedule_delayed_work(&smc->sock_put_work,
- SMC_CLOSE_SOCK_PUT_DELAY);
+ if (old_state != sk->sk_state) {
+ sk->sk_state_change(sk);
+ if ((sk->sk_state == SMC_CLOSED) &&
+ (sock_flag(sk, SOCK_DEAD) || !sk->sk_socket)) {
+ smc_conn_free(&smc->conn);
+ schedule_delayed_work(&smc->sock_put_work,
+ SMC_CLOSE_SOCK_PUT_DELAY);
+ }
}
release_sock(&smc->sk);
}
--
2.10.2