[PATCH net-next 11/32] rxrpc: De-atomic call->ackr_window and call->ackr_nr_unacked

[David Howells]

call->ackr_window doesn't need to be atomic as ACK generation and ACK
transmission are now done in the same thread, so drop the atomic64 handling
and split it into two separate members.

Similarly, call->ackr_nr_unacked doesn't need to be atomic now either.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
cc: linux-afs@xxxxxxxxxxxxxxxxxxx
---

 include/trace/events/rxrpc.h |   10 ++++++----
 net/rxrpc/ar-internal.h      |    5 +++--
 net/rxrpc/call_event.c       |    2 +-
 net/rxrpc/call_object.c      |    3 ++-
 net/rxrpc/input.c            |   14 +++++++-------
 net/rxrpc/output.c           |   13 +++++--------
 net/rxrpc/proc.c             |    4 +---
 net/rxrpc/recvmsg.c          |    4 ++--
 8 files changed, 27 insertions(+), 28 deletions(-)

diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index c47954aea7be..0b69a10bde38 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -1044,7 +1044,8 @@ TRACE_EVENT(rxrpc_receive,
 		    __field(enum rxrpc_receive_trace,	why		)
 		    __field(rxrpc_serial_t,		serial		)
 		    __field(rxrpc_seq_t,		seq		)
-		    __field(u64,			window		)
+		    __field(rxrpc_seq_t,		window		)
+		    __field(rxrpc_seq_t,		wtop		)
 			     ),
 
 	    TP_fast_assign(
@@ -1052,7 +1053,8 @@ TRACE_EVENT(rxrpc_receive,
 		    __entry->why = why;
 		    __entry->serial = serial;
 		    __entry->seq = seq;
-		    __entry->window = atomic64_read(&call->ackr_window);
+		    __entry->window = call->ackr_window;
+		    __entry->wtop = call->ackr_wtop;
 			   ),
 
 	    TP_printk("c=%08x %s r=%08x q=%08x w=%08x-%08x",
@@ -1060,8 +1062,8 @@ TRACE_EVENT(rxrpc_receive,
 		      __print_symbolic(__entry->why, rxrpc_receive_traces),
 		      __entry->serial,
 		      __entry->seq,
-		      lower_32_bits(__entry->window),
-		      upper_32_bits(__entry->window))
+		      __entry->window,
+		      __entry->wtop)
 	    );
 
 TRACE_EVENT(rxrpc_recvmsg,
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index ddba8048b7cb..fbfee05f0558 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -682,8 +682,9 @@ struct rxrpc_call {
 	/* Receive-phase ACK management (ACKs we send). */
 	u8			ackr_reason;	/* reason to ACK */
 	rxrpc_serial_t		ackr_serial;	/* serial of packet being ACK'd */
-	atomic64_t		ackr_window;	/* Base (in LSW) and top (in MSW) of SACK window */
-	atomic_t		ackr_nr_unacked; /* Number of unacked packets */
+	rxrpc_seq_t		ackr_window;	/* Base of SACK window */
+	rxrpc_seq_t		ackr_wtop;	/* Base of SACK window */
+	unsigned int		ackr_nr_unacked; /* Number of unacked packets */
 	atomic_t		ackr_nr_consumed; /* Number of packets needing hard ACK */
 	struct {
 #define RXRPC_SACK_SIZE 256
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index 768bc8a63038..60bec6feba4a 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -460,7 +460,7 @@ void rxrpc_input_call_event(struct rxrpc_call *call, struct sk_buff *skb)
 		rxrpc_send_ACK(call, RXRPC_ACK_IDLE, 0,
 			       rxrpc_propose_ack_rx_idle);
 
-	if (atomic_read(&call->ackr_nr_unacked) > 2) {
+	if (call->ackr_nr_unacked > 2) {
 		if (call->peer->rtt_count < 3)
 			rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
 				       rxrpc_propose_ack_ping_for_rtt);
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index a9c77be9107a..f31ba1c7d103 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -168,7 +168,8 @@ struct rxrpc_call *rxrpc_alloc_call(struct rxrpc_sock *rx, gfp_t gfp,
 	call->tx_total_len = -1;
 	call->next_rx_timo = 20 * HZ;
 	call->next_req_timo = 1 * HZ;
-	atomic64_set(&call->ackr_window, 0x100000001ULL);
+	call->ackr_window = 1;
+	call->ackr_wtop = 1;
 
 	memset(&call->sock_node, 0xed, sizeof(call->sock_node));
 
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index a72fd2f78fc0..c7a9c5c931de 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -321,7 +321,8 @@ static bool rxrpc_receiving_reply(struct rxrpc_call *call)
 static void rxrpc_input_update_ack_window(struct rxrpc_call *call,
 					  rxrpc_seq_t window, rxrpc_seq_t wtop)
 {
-	atomic64_set_release(&call->ackr_window, ((u64)wtop) << 32 | window);
+	call->ackr_window = window;
+	call->ackr_wtop = wtop;
 }
 
 /*
@@ -349,9 +350,8 @@ static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb,
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 	struct sk_buff *oos;
 	rxrpc_serial_t serial = sp->hdr.serial;
-	u64 win = atomic64_read(&call->ackr_window);
-	rxrpc_seq_t window = lower_32_bits(win);
-	rxrpc_seq_t wtop = upper_32_bits(win);
+	rxrpc_seq_t window = call->ackr_window;
+	rxrpc_seq_t wtop = call->ackr_wtop;
 	rxrpc_seq_t wlimit = window + call->rx_winsize - 1;
 	rxrpc_seq_t seq = sp->hdr.seq;
 	bool last = sp->hdr.flags & RXRPC_LAST_PACKET;
@@ -404,7 +404,7 @@ static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb,
 		else if (!skb_queue_empty(&call->rx_oos_queue))
 			ack_reason = RXRPC_ACK_DELAY;
 		else
-			atomic_inc_return(&call->ackr_nr_unacked);
+			call->ackr_nr_unacked++;
 
 		window++;
 		if (after(window, wtop))
@@ -553,8 +553,8 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
 	rxrpc_serial_t serial = sp->hdr.serial;
 	rxrpc_seq_t seq0 = sp->hdr.seq;
 
-	_enter("{%llx,%x},{%u,%x}",
-	       atomic64_read(&call->ackr_window), call->rx_highest_seq,
+	_enter("{%x,%x,%x},{%u,%x}",
+	       call->ackr_window, call->ackr_wtop, call->rx_highest_seq,
 	       skb->len, seq0);
 
 	state = READ_ONCE(call->state);
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 2a44958b1bc7..3e132d9371ee 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -86,20 +86,18 @@ static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
 	unsigned int qsize;
 	rxrpc_seq_t window, wtop, wrap_point, ix, first;
 	int rsize;
-	u64 wtmp;
 	u32 mtu, jmax;
 	u8 *ackp = txb->acks;
 	u8 sack_buffer[sizeof(call->ackr_sack_table)] __aligned(8);
 
-	atomic_set(&call->ackr_nr_unacked, 0);
+	call->ackr_nr_unacked = 0;
 	atomic_set(&call->ackr_nr_consumed, 0);
 	rxrpc_inc_stat(call->rxnet, stat_tx_ack_fill);
 
 	/* Barrier against rxrpc_input_data(). */
 retry:
-	wtmp   = atomic64_read_acquire(&call->ackr_window);
-	window = lower_32_bits(wtmp);
-	wtop   = upper_32_bits(wtmp);
+	window = call->ackr_window;
+	wtop   = call->ackr_wtop;
 	txb->ack.firstPacket = htonl(window);
 	txb->ack.nAcks = 0;
 
@@ -111,9 +109,8 @@ static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
 		 */
 		memcpy(sack_buffer, call->ackr_sack_table, sizeof(sack_buffer));
 		wrap_point = window + RXRPC_SACK_SIZE - 1;
-		wtmp   = atomic64_read_acquire(&call->ackr_window);
-		window = lower_32_bits(wtmp);
-		wtop   = upper_32_bits(wtmp);
+		window = call->ackr_window;
+		wtop   = call->ackr_wtop;
 		if (after(wtop, wrap_point)) {
 			cond_resched();
 			goto retry;
diff --git a/net/rxrpc/proc.c b/net/rxrpc/proc.c
index 3a59591ec061..38ea7df3fc42 100644
--- a/net/rxrpc/proc.c
+++ b/net/rxrpc/proc.c
@@ -54,7 +54,6 @@ static int rxrpc_call_seq_show(struct seq_file *seq, void *v)
 	unsigned long timeout = 0;
 	rxrpc_seq_t acks_hard_ack;
 	char lbuff[50], rbuff[50];
-	u64 wtmp;
 
 	if (v == &rxnet->calls) {
 		seq_puts(seq,
@@ -81,7 +80,6 @@ static int rxrpc_call_seq_show(struct seq_file *seq, void *v)
 	}
 
 	acks_hard_ack = READ_ONCE(call->acks_hard_ack);
-	wtmp   = atomic64_read_acquire(&call->ackr_window);
 	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",
@@ -96,7 +94,7 @@ static int rxrpc_call_seq_show(struct seq_file *seq, void *v)
 		   call->abort_code,
 		   call->debug_id,
 		   acks_hard_ack, READ_ONCE(call->tx_top) - acks_hard_ack,
-		   lower_32_bits(wtmp), upper_32_bits(wtmp) - lower_32_bits(wtmp),
+		   call->ackr_window, call->ackr_wtop - call->ackr_window,
 		   call->rx_serial,
 		   call->cong_cwnd,
 		   timeout);
diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c
index 88298ab8a9d7..56a31aebea38 100644
--- a/net/rxrpc/recvmsg.c
+++ b/net/rxrpc/recvmsg.c
@@ -177,7 +177,7 @@ static int rxrpc_recvmsg_term(struct rxrpc_call *call, struct msghdr *msg)
 	}
 
 	trace_rxrpc_recvdata(call, rxrpc_recvmsg_terminal,
-			     lower_32_bits(atomic64_read(&call->ackr_window)) - 1,
+			     call->ackr_window - 1,
 			     call->rx_pkt_offset, call->rx_pkt_len, ret);
 	return ret;
 }
@@ -293,7 +293,7 @@ static int rxrpc_recvmsg_data(struct socket *sock, struct rxrpc_call *call,
 	rx_pkt_len = call->rx_pkt_len;
 
 	if (call->state >= RXRPC_CALL_SERVER_ACK_REQUEST) {
-		seq = lower_32_bits(atomic64_read(&call->ackr_window)) - 1;
+		seq = call->ackr_window - 1;
 		ret = 1;
 		goto done;
 	}