[PATCH net-next 06/23] rxrpc: Fix loss of final ack on shutdown

From: David Howells
Date: Thu Oct 01 2020 - 10:57:40 EST


Fix the loss of transmission of a call's final ack when a socket gets shut
down. This means that the server will retransmit the last data packet or
send a ping ack and then get an ICMP indicating the port got closed. The
server will then view this as a failure.

Fixes: 3136ef49a14c ("rxrpc: Delay terminal ACK transmission on a client call")
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

net/rxrpc/ar-internal.h | 1 +
net/rxrpc/conn_client.c | 3 +++
net/rxrpc/conn_event.c | 6 +++---
3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 19f714386654..0b4233fdd740 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -834,6 +834,7 @@ void rxrpc_clean_up_local_conns(struct rxrpc_local *);
* conn_event.c
*/
void rxrpc_process_connection(struct work_struct *);
+void rxrpc_process_delayed_final_acks(struct rxrpc_connection *, bool);

/*
* conn_object.c
diff --git a/net/rxrpc/conn_client.c b/net/rxrpc/conn_client.c
index 5d9adfd4c84f..7e574c75be8e 100644
--- a/net/rxrpc/conn_client.c
+++ b/net/rxrpc/conn_client.c
@@ -906,6 +906,9 @@ static void rxrpc_unbundle_conn(struct rxrpc_connection *conn)

_enter("C=%x", conn->debug_id);

+ if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
+ rxrpc_process_delayed_final_acks(conn, true);
+
spin_lock(&bundle->channel_lock);
bindex = conn->bundle_shift / RXRPC_MAXCALLS;
if (bundle->conns[bindex] == conn) {
diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index bba5d7906df6..c1b64e1dfc4e 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -397,7 +397,7 @@ static void rxrpc_secure_connection(struct rxrpc_connection *conn)
/*
* Process delayed final ACKs that we haven't subsumed into a subsequent call.
*/
-static void rxrpc_process_delayed_final_acks(struct rxrpc_connection *conn)
+void rxrpc_process_delayed_final_acks(struct rxrpc_connection *conn, bool force)
{
unsigned long j = jiffies, next_j;
unsigned int channel;
@@ -416,7 +416,7 @@ static void rxrpc_process_delayed_final_acks(struct rxrpc_connection *conn)
smp_rmb(); /* vs rxrpc_disconnect_client_call */
ack_at = READ_ONCE(chan->final_ack_at);

- if (time_before(j, ack_at)) {
+ if (time_before(j, ack_at) && !force) {
if (time_before(ack_at, next_j)) {
next_j = ack_at;
set = true;
@@ -450,7 +450,7 @@ static void rxrpc_do_process_connection(struct rxrpc_connection *conn)

/* Process delayed ACKs whose time has come. */
if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
- rxrpc_process_delayed_final_acks(conn);
+ rxrpc_process_delayed_final_acks(conn, false);

/* go through the conn-level event packets, releasing the ref on this
* connection that each one has when we've finished with it */