rxrpc: call->acks_hard_ack is now the same call->tx_bottom, so remove it

Now that packets are removed from the Tx queue in the rotation function
rather than being cleaned up later, call->acks_hard_ack now advances in
step with call->tx_bottom, so remove it.

Some of the places call->acks_hard_ack is used in the rxrpc tracepoints are
replaced by call->acks_first_seq instead as that's the peer's reported idea
of the hard-ACK point.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: https://patch.msgid.link/20241204074710.990092-20-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

5 files changed, 16 insertions, 18 deletions

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index bcce4862b0b7..6683043cee3f 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -759,7 +759,6 @@ struct rxrpc_call {
 	ktime_t			acks_latest_ts;	/* Timestamp of latest ACK received */
 	rxrpc_seq_t		acks_first_seq;	/* first sequence number received */
 	rxrpc_seq_t		acks_prev_seq;	/* Highest previousPacket received */
-	rxrpc_seq_t		acks_hard_ack;	/* Latest hard-ack point */
 	rxrpc_seq_t		acks_lowest_nak; /* Lowest NACK in the buffer (or ==tx_hard_ack) */
 	rxrpc_serial_t		acks_highest_serial; /* Highest serial number ACK'd */
 };
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index 90e3d9395675..2311e5c737e8 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -109,7 +109,7 @@ void rxrpc_resend(struct rxrpc_call *call, struct sk_buff *ack_skb)
 	bool unacked = false, did_send = false;
 	unsigned int qix;
 
-	_enter("{%d,%d}", call->acks_hard_ack, call->tx_top);
+	_enter("{%d,%d}", call->tx_bottom, call->tx_top);
 
 	if (call->tx_bottom == call->tx_top)
 		goto no_resend;
@@ -267,7 +267,7 @@ static void rxrpc_close_tx_phase(struct rxrpc_call *call)
 static unsigned int rxrpc_tx_window_space(struct rxrpc_call *call)
 {
 	int winsize = umin(call->tx_winsize, call->cong_cwnd + call->cong_extra);
-	int in_flight = call->tx_top - call->acks_hard_ack;
+	int in_flight = call->tx_top - call->tx_bottom;
 
 	return max(winsize - in_flight, 0);
 }
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index cfdd23042d4c..afb87a3322da 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -40,7 +40,7 @@ static void rxrpc_congestion_management(struct rxrpc_call *call,
 	bool resend = false;
 
 	summary->flight_size =
-		(call->tx_top - call->acks_hard_ack) - summary->nr_acks;
+		(call->tx_top - call->tx_bottom) - summary->nr_acks;
 
 	if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) {
 		summary->retrans_timeo = true;
@@ -175,7 +175,7 @@ send_extra_data:
 	 * state.
 	 */
 	if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ||
-	    summary->nr_acks != call->tx_top - call->acks_hard_ack) {
+	    summary->nr_acks != call->tx_top - call->tx_bottom) {
 		call->cong_extra++;
 		wake_up(&call->waitq);
 	}
@@ -218,7 +218,7 @@ static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
 	rxrpc_seq_t seq = call->tx_bottom + 1;
 	bool rot_last = false;
 
-	_enter("%x,%x,%x", call->tx_bottom, call->acks_hard_ack, to);
+	_enter("%x,%x", call->tx_bottom, to);
 
 	trace_rxrpc_tx_rotate(call, seq, to);
 	trace_rxrpc_tq(call, tq, seq, rxrpc_tq_rotate);
@@ -246,7 +246,6 @@ static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
 		tq->bufs[ix] = NULL;
 
 		WRITE_ONCE(call->tx_bottom, seq);
-		WRITE_ONCE(call->acks_hard_ack, seq);
 		trace_rxrpc_txqueue(call, (rot_last ?
 					   rxrpc_txqueue_rotate_last :
 					   rxrpc_txqueue_rotate));
@@ -278,9 +277,9 @@ static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
 		}
 	}
 
-	_debug("%x,%x,%x,%d", to, call->acks_hard_ack, call->tx_top, rot_last);
+	_debug("%x,%x,%x,%d", to, call->tx_bottom, call->tx_top, rot_last);
 
-	if (call->acks_lowest_nak == call->acks_hard_ack) {
+	if (call->acks_lowest_nak == call->tx_bottom) {
 		call->acks_lowest_nak = to;
 	} else if (after(to, call->acks_lowest_nak)) {
 		summary->new_low_nack = true;
@@ -968,7 +967,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 	if (unlikely(summary.ack_reason == RXRPC_ACK_OUT_OF_SEQUENCE) &&
 	    first_soft_ack == 1 &&
 	    prev_pkt == 0 &&
-	    call->acks_hard_ack == 0 &&
+	    call->tx_bottom == 0 &&
 	    rxrpc_is_client_call(call)) {
 		rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 					  0, -ENETRESET);
@@ -1033,13 +1032,13 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 		goto send_response;
 	}
 
-	if (before(hard_ack, call->acks_hard_ack) ||
+	if (before(hard_ack, call->tx_bottom) ||
 	    after(hard_ack, call->tx_top))
 		return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_outside_window);
 	if (nr_acks > call->tx_top - hard_ack)
 		return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_sack_overflow);
 
-	if (after(hard_ack, call->acks_hard_ack)) {
+	if (after(hard_ack, call->tx_bottom)) {
 		if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) {
 			rxrpc_end_tx_phase(call, false, rxrpc_eproto_unexpected_ack);
 			goto send_response;
diff --git a/net/rxrpc/proc.c b/net/rxrpc/proc.c
index 249e1ed9c5c9..a8325b8e33c2 100644
--- a/net/rxrpc/proc.c
+++ b/net/rxrpc/proc.c
@@ -52,7 +52,7 @@ static int rxrpc_call_seq_show(struct seq_file *seq, void *v)
 	struct rxrpc_call *call;
 	struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq));
 	enum rxrpc_call_state state;
-	rxrpc_seq_t acks_hard_ack;
+	rxrpc_seq_t tx_bottom;
 	char lbuff[50], rbuff[50];
 	long timeout = 0;
 
@@ -79,7 +79,7 @@ static int rxrpc_call_seq_show(struct seq_file *seq, void *v)
 	if (state != RXRPC_CALL_SERVER_PREALLOC)
 		timeout = ktime_ms_delta(READ_ONCE(call->expect_rx_by), ktime_get_real());
 
-	acks_hard_ack = READ_ONCE(call->acks_hard_ack);
+	tx_bottom = READ_ONCE(call->tx_bottom);
 	seq_printf(seq,
 		   "UDP   %-47.47s %-47.47s %4x %08x %08x %s %3u"
 		   " %-8.8s %08x %08x %08x %02x %08x %02x %08x %02x %06lx\n",
@@ -93,7 +93,7 @@ static int rxrpc_call_seq_show(struct seq_file *seq, void *v)
 		   rxrpc_call_states[state],
 		   call->abort_code,
 		   call->debug_id,
-		   acks_hard_ack, READ_ONCE(call->tx_top) - acks_hard_ack,
+		   tx_bottom, READ_ONCE(call->tx_top) - tx_bottom,
 		   call->ackr_window, call->ackr_wtop - call->ackr_window,
 		   call->rx_serial,
 		   call->cong_cwnd,
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index 85b35b11755d..dfbf9f4b24b6 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -140,7 +140,7 @@ static int rxrpc_wait_for_tx_window_waitall(struct rxrpc_sock *rx,
 		rtt = 2;
 
 	timeout = rtt;
-	tx_start = READ_ONCE(call->acks_hard_ack);
+	tx_start = READ_ONCE(call->tx_bottom);
 
 	for (;;) {
 		set_current_state(TASK_UNINTERRUPTIBLE);
@@ -197,8 +197,8 @@ static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
 	DECLARE_WAITQUEUE(myself, current);
 	int ret;
 
-	_enter(",{%u,%u,%u,%u}",
-	       call->tx_bottom, call->acks_hard_ack, call->tx_top, call->tx_winsize);
+	_enter(",{%u,%u,%u}",
+	       call->tx_bottom, call->tx_top, call->tx_winsize);
 
 	add_wait_queue(&call->waitq, &myself);