linux-kernel - [PATCH net-next 2/2] rxrpc: Fix loss of final ack on shutdown

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Message-ID: <160276676546.955243.15747495003059936378.stgit@warthog.procyon.org.uk>
Date:   Thu, 15 Oct 2020 13:59:25 +0100
From:   David Howells <dhowells@...hat.com>
To:     netdev@...r.kernel.org
Cc:     dhowells@...hat.com, linux-afs@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH net-next 2/2] rxrpc: Fix loss of final ack on shutdown

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@...hat.com>
---

 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 c9287b6551df..dce48162f6c2 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -831,6 +831,7 @@ 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 6b7c6f4a82e3..aff184145ffa 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 */