rxrpc: Fix loss of PING RESPONSE ACK production due to PING ACKs

Separate the output of PING ACKs from the output of other sorts of ACK so
that if we receive a PING ACK and schedule transmission of a PING RESPONSE
ACK, the response doesn't get cancelled by a PING ACK we happen to be
scheduling transmission of at the same time.

If a PING RESPONSE gets lost, the other side might just sit there waiting
for it and refuse to proceed otherwise.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index ef849a12a0f0..b56676be07c7 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -398,6 +398,7 @@ enum rxrpc_call_flag {
 	RXRPC_CALL_EXPOSED,		/* The call was exposed to the world */
 	RXRPC_CALL_RX_LAST,		/* Received the last packet (at rxtx_top) */
 	RXRPC_CALL_TX_LAST,		/* Last packet in Tx buffer (at rxtx_top) */
+	RXRPC_CALL_SEND_PING,		/* A ping will need to be sent */
 	RXRPC_CALL_PINGING,		/* Ping in process */
 	RXRPC_CALL_RETRANS_TIMEOUT,	/* Retransmission due to timeout occurred */
 };
@@ -410,6 +411,7 @@ enum rxrpc_call_event {
 	RXRPC_CALL_EV_ABORT,		/* need to generate abort */
 	RXRPC_CALL_EV_TIMER,		/* Timer expired */
 	RXRPC_CALL_EV_RESEND,		/* Tx resend required */
+	RXRPC_CALL_EV_PING,		/* Ping send required */
 };
 
 /*
@@ -466,6 +468,7 @@ struct rxrpc_call {
 	struct rxrpc_sock __rcu	*socket;	/* socket responsible */
 	ktime_t			ack_at;		/* When deferred ACK needs to happen */
 	ktime_t			resend_at;	/* When next resend needs to happen */
+	ktime_t			ping_at;	/* When next to send a ping */
 	ktime_t			expire_at;	/* When the call times out */
 	struct timer_list	timer;		/* Combined event timer */
 	struct work_struct	processor;	/* Event processor */
@@ -558,8 +561,10 @@ struct rxrpc_call {
 	rxrpc_seq_t		ackr_prev_seq;	/* previous sequence number received */
 	rxrpc_seq_t		ackr_consumed;	/* Highest packet shown consumed */
 	rxrpc_seq_t		ackr_seen;	/* Highest packet shown seen */
-	rxrpc_serial_t		ackr_ping;	/* Last ping sent */
-	ktime_t			ackr_ping_time;	/* Time last ping sent */
+
+	/* ping management */
+	rxrpc_serial_t		ping_serial;	/* Last ping sent */
+	ktime_t			ping_time;	/* Time last ping sent */
 
 	/* transmission-phase ACK management */
 	ktime_t			acks_latest_ts;	/* Timestamp of latest ACK received */
@@ -730,6 +735,7 @@ enum rxrpc_timer_trace {
 	rxrpc_timer_init_for_reply,
 	rxrpc_timer_expired,
 	rxrpc_timer_set_for_ack,
+	rxrpc_timer_set_for_ping,
 	rxrpc_timer_set_for_resend,
 	rxrpc_timer_set_for_send,
 	rxrpc_timer__nr_trace
@@ -1068,7 +1074,7 @@ extern const s8 rxrpc_ack_priority[];
 /*
  * output.c
  */
-int rxrpc_send_ack_packet(struct rxrpc_call *);
+int rxrpc_send_ack_packet(struct rxrpc_call *, bool);
 int rxrpc_send_abort_packet(struct rxrpc_call *);
 int rxrpc_send_data_packet(struct rxrpc_call *, struct sk_buff *, bool);
 void rxrpc_reject_packets(struct rxrpc_local *);