Merge tag 'rxrpc-rewrite-20160929' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

David Howells says:

====================
rxrpc: Fixes and adjustments

This set of patches contains some fixes and adjustments:

 (1) Connections for exclusive calls are being reused because the check to
     work out whether to set RXRPC_CONN_DONT_REUSE is checking where the
     parameters will be copied to (but haven't yet).

 (2) Make Tx loss-injection go through the normal return, so the state gets
     set correctly for what the code thinks it has done.

     Note lost Tx packets in the tx_data trace rather than the skb
     tracepoint.

 (3) Activate channels according to the current state from within the
     channel_lock to avoid someone changing it on us.

 (4) Reduce the local endpoint's services list to a single pointer as we
     don't allow service AF_RXRPC sockets to share UDP ports with other
     AF_RXRPC sockets, so there can't be more than one element in the list.

 (5) Request more ACKs in slow-start mode to help monitor the state driving
     the window configuration.

 (6) Display the serial number of the packet being ACK'd rather than the
     ACK packet's own serial number in the congestion trace as this can be
     related to other entries in the trace.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

13 files changed, 68 insertions, 64 deletions

diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index ada12d00118c..8ba8d76e856a 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -258,15 +258,16 @@ TRACE_EVENT(rxrpc_rx_ack,
 
 TRACE_EVENT(rxrpc_tx_data,
 	    TP_PROTO(struct rxrpc_call *call, rxrpc_seq_t seq,
-		     rxrpc_serial_t serial, u8 flags, bool lose),
+		     rxrpc_serial_t serial, u8 flags, bool retrans, bool lose),
 
-	    TP_ARGS(call, seq, serial, flags, lose),
+	    TP_ARGS(call, seq, serial, flags, retrans, lose),
 
 	    TP_STRUCT__entry(
 		    __field(struct rxrpc_call *,	call		)
 		    __field(rxrpc_seq_t,		seq		)
 		    __field(rxrpc_serial_t,		serial		)
 		    __field(u8,				flags		)
+		    __field(bool,			retrans		)
 		    __field(bool,			lose		)
 			     ),
 
@@ -275,6 +276,7 @@ TRACE_EVENT(rxrpc_tx_data,
 		    __entry->seq = seq;
 		    __entry->serial = serial;
 		    __entry->flags = flags;
+		    __entry->retrans = retrans;
 		    __entry->lose = lose;
 			   ),
 
diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index 8dbf7bed2cc4..44c9c2b0b190 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -136,7 +136,8 @@ static int rxrpc_bind(struct socket *sock, struct sockaddr *saddr, int len)
 	struct sockaddr_rxrpc *srx = (struct sockaddr_rxrpc *)saddr;
 	struct sock *sk = sock->sk;
 	struct rxrpc_local *local;
-	struct rxrpc_sock *rx = rxrpc_sk(sk), *prx;
+	struct rxrpc_sock *rx = rxrpc_sk(sk);
+	u16 service_id = srx->srx_service;
 	int ret;
 
 	_enter("%p,%p,%d", rx, saddr, len);
@@ -160,15 +161,12 @@ static int rxrpc_bind(struct socket *sock, struct sockaddr *saddr, int len)
 		goto error_unlock;
 	}
 
-	if (rx->srx.srx_service) {
+	if (service_id) {
 		write_lock(&local->services_lock);
-		hlist_for_each_entry(prx, &local->services, listen_link) {
-			if (prx->srx.srx_service == rx->srx.srx_service)
-				goto service_in_use;
-		}
-
+		if (rcu_access_pointer(local->service))
+			goto service_in_use;
 		rx->local = local;
-		hlist_add_head_rcu(&rx->listen_link, &local->services);
+		rcu_assign_pointer(local->service, rx);
 		write_unlock(&local->services_lock);
 
 		rx->sk.sk_state = RXRPC_SERVER_BOUND;
@@ -599,7 +597,6 @@ static int rxrpc_create(struct net *net, struct socket *sock, int protocol,
 	rx->family = protocol;
 	rx->calls = RB_ROOT;
 
-	INIT_HLIST_NODE(&rx->listen_link);
 	spin_lock_init(&rx->incoming_lock);
 	INIT_LIST_HEAD(&rx->sock_calls);
 	INIT_LIST_HEAD(&rx->to_be_accepted);
@@ -681,11 +678,9 @@ static int rxrpc_release_sock(struct sock *sk)
 	sk->sk_state = RXRPC_CLOSE;
 	spin_unlock_bh(&sk->sk_receive_queue.lock);
 
-	ASSERTCMP(rx->listen_link.next, !=, LIST_POISON1);
-
-	if (!hlist_unhashed(&rx->listen_link)) {
+	if (rx->local && rx->local->service == rx) {
 		write_lock(&rx->local->services_lock);
-		hlist_del_rcu(&rx->listen_link);
+		rx->local->service = NULL;
 		write_unlock(&rx->local->services_lock);
 	}
 
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index ca96e547cb9a..539db54697f9 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -93,7 +93,6 @@ struct rxrpc_sock {
 	rxrpc_notify_new_call_t	notify_new_call; /* Func to notify of new call */
 	rxrpc_discard_new_call_t discard_new_call; /* Func to discard a new call */
 	struct rxrpc_local	*local;		/* local endpoint */
-	struct hlist_node	listen_link;	/* link in the local endpoint's listen list */
 	struct rxrpc_backlog	*backlog;	/* Preallocation for services */
 	spinlock_t		incoming_lock;	/* Incoming call vs service shutdown lock */
 	struct list_head	sock_calls;	/* List of calls owned by this socket */
@@ -216,7 +215,7 @@ struct rxrpc_local {
 	struct list_head	link;
 	struct socket		*socket;	/* my UDP socket */
 	struct work_struct	processor;
-	struct hlist_head	services;	/* services listening on this endpoint */
+	struct rxrpc_sock __rcu	*service;	/* Service(s) listening on this endpoint */
 	struct rw_semaphore	defrag_sem;	/* control re-enablement of IP DF bit */
 	struct sk_buff_head	reject_queue;	/* packets awaiting rejection */
 	struct sk_buff_head	event_queue;	/* endpoint event packets awaiting processing */
@@ -603,7 +602,6 @@ enum rxrpc_skb_trace {
 	rxrpc_skb_tx_cleaned,
 	rxrpc_skb_tx_freed,
 	rxrpc_skb_tx_got,
-	rxrpc_skb_tx_lost,
 	rxrpc_skb_tx_new,
 	rxrpc_skb_tx_rotated,
 	rxrpc_skb_tx_seen,
@@ -1073,7 +1071,7 @@ extern const s8 rxrpc_ack_priority[];
  * output.c
  */
 int rxrpc_send_call_packet(struct rxrpc_call *, u8);
-int rxrpc_send_data_packet(struct rxrpc_call *, struct sk_buff *);
+int rxrpc_send_data_packet(struct rxrpc_call *, struct sk_buff *, bool);
 void rxrpc_reject_packets(struct rxrpc_local *);
 
 /*
diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c
index a8d39d7cf42c..3cac231d8405 100644
--- a/net/rxrpc/call_accept.c
+++ b/net/rxrpc/call_accept.c
@@ -331,14 +331,14 @@ struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local,
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 	struct rxrpc_sock *rx;
 	struct rxrpc_call *call;
+	u16 service_id = sp->hdr.serviceId;
 
 	_enter("");
 
 	/* Get the socket providing the service */
-	hlist_for_each_entry_rcu_bh(rx, &local->services, listen_link) {
-		if (rx->srx.srx_service == sp->hdr.serviceId)
-			goto found_service;
-	}
+	rx = rcu_dereference(local->service);
+	if (service_id == rx->srx.srx_service)
+		goto found_service;
 
 	trace_rxrpc_abort("INV", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
 			  RX_INVALID_OPERATION, EOPNOTSUPP);
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index 0e8478012212..1f6c7633b964 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -256,7 +256,7 @@ static void rxrpc_resend(struct rxrpc_call *call)
 		rxrpc_get_skb(skb, rxrpc_skb_tx_got);
 		spin_unlock_bh(&call->lock);
 
-		if (rxrpc_send_data_packet(call, skb) < 0) {
+		if (rxrpc_send_data_packet(call, skb, true) < 0) {
 			rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
 			return;
 		}
diff --git a/net/rxrpc/conn_client.c b/net/rxrpc/conn_client.c
index c76a125df891..60ef9605167e 100644
--- a/net/rxrpc/conn_client.c
+++ b/net/rxrpc/conn_client.c
@@ -200,7 +200,7 @@ rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, gfp_t gfp)
 	}
 
 	atomic_set(&conn->usage, 1);
-	if (conn->params.exclusive)
+	if (cp->exclusive)
 		__set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
 
 	conn->params		= *cp;
@@ -576,28 +576,42 @@ static void rxrpc_activate_one_channel(struct rxrpc_connection *conn,
 }
 
 /*
+ * Assign channels and callNumbers to waiting calls with channel_lock
+ * held by caller.
+ */
+static void rxrpc_activate_channels_locked(struct rxrpc_connection *conn)
+{
+	u8 avail, mask;
+
+	switch (conn->cache_state) {
+	case RXRPC_CONN_CLIENT_ACTIVE:
+		mask = RXRPC_ACTIVE_CHANS_MASK;
+		break;
+	default:
+		return;
+	}
+
+	while (!list_empty(&conn->waiting_calls) &&
+	       (avail = ~conn->active_chans,
+		avail &= mask,
+		avail != 0))
+		rxrpc_activate_one_channel(conn, __ffs(avail));
+}
+
+/*
  * Assign channels and callNumbers to waiting calls.
  */
 static void rxrpc_activate_channels(struct rxrpc_connection *conn)
 {
-	unsigned char mask;
-
 	_enter("%d", conn->debug_id);
 
 	trace_rxrpc_client(conn, -1, rxrpc_client_activate_chans);
 
-	if (conn->cache_state != RXRPC_CONN_CLIENT_ACTIVE ||
-	    conn->active_chans == RXRPC_ACTIVE_CHANS_MASK)
+	if (conn->active_chans == RXRPC_ACTIVE_CHANS_MASK)
 		return;
 
 	spin_lock(&conn->channel_lock);
-
-	while (!list_empty(&conn->waiting_calls) &&
-	       (mask = ~conn->active_chans,
-		mask &= RXRPC_ACTIVE_CHANS_MASK,
-		mask != 0))
-		rxrpc_activate_one_channel(conn, __ffs(mask));
-
+	rxrpc_activate_channels_locked(conn);
 	spin_unlock(&conn->channel_lock);
 	_leave("");
 }
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 094720dd1eaf..1461d30583c9 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -41,10 +41,10 @@ static void rxrpc_proto_abort(const char *why,
  */
 static void rxrpc_congestion_management(struct rxrpc_call *call,
 					struct sk_buff *skb,
-					struct rxrpc_ack_summary *summary)
+					struct rxrpc_ack_summary *summary,
+					rxrpc_serial_t acked_serial)
 {
 	enum rxrpc_congest_change change = rxrpc_cong_no_change;
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 	unsigned int cumulative_acks = call->cong_cumul_acks;
 	unsigned int cwnd = call->cong_cwnd;
 	bool resend = false;
@@ -172,7 +172,7 @@ out_no_clear_ca:
 		cwnd = RXRPC_RXTX_BUFF_SIZE - 1;
 	call->cong_cwnd = cwnd;
 	call->cong_cumul_acks = cumulative_acks;
-	trace_rxrpc_congest(call, summary, sp->hdr.serial, change);
+	trace_rxrpc_congest(call, summary, acked_serial, change);
 	if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 		rxrpc_queue_call(call);
 	return;
@@ -848,7 +848,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 				  false, true,
 				  rxrpc_propose_ack_ping_for_lost_reply);
 
-	return rxrpc_congestion_management(call, skb, &summary);
+	return rxrpc_congestion_management(call, skb, &summary, acked_serial);
 }
 
 /*
diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c
index e3fad80b0795..ff4864d550b8 100644
--- a/net/rxrpc/local_object.c
+++ b/net/rxrpc/local_object.c
@@ -86,7 +86,6 @@ static struct rxrpc_local *rxrpc_alloc_local(const struct sockaddr_rxrpc *srx)
 		atomic_set(&local->usage, 1);
 		INIT_LIST_HEAD(&local->link);
 		INIT_WORK(&local->processor, rxrpc_local_processor);
-		INIT_HLIST_HEAD(&local->services);
 		init_rwsem(&local->defrag_sem);
 		skb_queue_head_init(&local->reject_queue);
 		skb_queue_head_init(&local->event_queue);
@@ -292,7 +291,7 @@ static void rxrpc_local_destroyer(struct rxrpc_local *local)
 	mutex_unlock(&rxrpc_local_mutex);
 
 	ASSERT(RB_EMPTY_ROOT(&local->client_conns));
-	ASSERT(hlist_empty(&local->services));
+	ASSERT(!local->service);
 
 	if (socket) {
 		local->socket = NULL;
diff --git a/net/rxrpc/misc.c b/net/rxrpc/misc.c
index aedb8978226d..47dddacdbb91 100644
--- a/net/rxrpc/misc.c
+++ b/net/rxrpc/misc.c
@@ -108,7 +108,6 @@ const char rxrpc_skb_traces[rxrpc_skb__nr_trace][7] = {
 	[rxrpc_skb_tx_cleaned]		= "Tx CLN",
 	[rxrpc_skb_tx_freed]		= "Tx FRE",
 	[rxrpc_skb_tx_got]		= "Tx GOT",
-	[rxrpc_skb_tx_lost]		= "Tx *L*",
 	[rxrpc_skb_tx_new]		= "Tx NEW",
 	[rxrpc_skb_tx_rotated]		= "Tx ROT",
 	[rxrpc_skb_tx_seen]		= "Tx SEE",
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index cf43a715685e..0d47db886f6e 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -238,7 +238,8 @@ out:
 /*
  * send a packet through the transport endpoint
  */
-int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb)
+int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
+			   bool retrans)
 {
 	struct rxrpc_connection *conn = call->conn;
 	struct rxrpc_wire_header whdr;
@@ -247,6 +248,7 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb)
 	struct kvec iov[2];
 	rxrpc_serial_t serial;
 	size_t len;
+	bool lost = false;
 	int ret, opt;
 
 	_enter(",{%d}", skb->len);
@@ -281,7 +283,8 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb)
 	/* If our RTT cache needs working on, request an ACK.  Also request
 	 * ACKs if a DATA packet appears to have been lost.
 	 */
-	if (call->cong_mode == RXRPC_CALL_FAST_RETRANSMIT ||
+	if (retrans ||
+	    call->cong_mode == RXRPC_CALL_SLOW_START ||
 	    (call->peer->rtt_usage < 3 && sp->hdr.seq & 1) ||
 	    ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
 			 ktime_get_real()))
@@ -290,11 +293,9 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb)
 	if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
 		static int lose;
 		if ((lose++ & 7) == 7) {
-			trace_rxrpc_tx_data(call, sp->hdr.seq, serial,
-					    whdr.flags, true);
-			rxrpc_lose_skb(skb, rxrpc_skb_tx_lost);
-			_leave(" = 0 [lose]");
-			return 0;
+			ret = 0;
+			lost = true;
+			goto done;
 		}
 	}
 
@@ -319,7 +320,8 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb)
 		goto send_fragmentable;
 
 done:
-	trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags, false);
+	trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags,
+			    retrans, lost);
 	if (ret >= 0) {
 		ktime_t now = ktime_get_real();
 		skb->tstamp = now;
diff --git a/net/rxrpc/security.c b/net/rxrpc/security.c
index 82d8134e9287..7d921e56e715 100644
--- a/net/rxrpc/security.c
+++ b/net/rxrpc/security.c
@@ -131,10 +131,10 @@ int rxrpc_init_server_conn_security(struct rxrpc_connection *conn)
 
 	/* find the service */
 	read_lock(&local->services_lock);
-	hlist_for_each_entry(rx, &local->services, listen_link) {
-		if (rx->srx.srx_service == conn->params.service_id)
-			goto found_service;
-	}
+	rx = rcu_dereference_protected(local->service,
+				       lockdep_is_held(&local->services_lock));
+	if (rx && rx->srx.srx_service == conn->params.service_id)
+		goto found_service;
 
 	/* the service appears to have died */
 	read_unlock(&local->services_lock);
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index 1f8040d82395..d8dfdce874d8 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -144,7 +144,7 @@ static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
 	if (seq == 1 && rxrpc_is_client_call(call))
 		rxrpc_expose_client_call(call);
 
-	ret = rxrpc_send_data_packet(call, skb);
+	ret = rxrpc_send_data_packet(call, skb, false);
 	if (ret < 0) {
 		_debug("need instant resend %d", ret);
 		rxrpc_instant_resend(call, ix);
diff --git a/net/rxrpc/skbuff.c b/net/rxrpc/skbuff.c
index 5154cbf7e540..67b02c45271b 100644
--- a/net/rxrpc/skbuff.c
+++ b/net/rxrpc/skbuff.c
@@ -77,14 +77,9 @@ void rxrpc_lose_skb(struct sk_buff *skb, enum rxrpc_skb_trace op)
 	if (skb) {
 		int n;
 		CHECK_SLAB_OKAY(&skb->users);
-		if (op == rxrpc_skb_tx_lost) {
-			n = atomic_read(select_skb_count(op));
-			trace_rxrpc_skb(skb, op, atomic_read(&skb->users), n, here);
-		} else {
-			n = atomic_dec_return(select_skb_count(op));
-			trace_rxrpc_skb(skb, op, atomic_read(&skb->users), n, here);
-			kfree_skb(skb);
-		}
+		n = atomic_dec_return(select_skb_count(op));
+		trace_rxrpc_skb(skb, op, atomic_read(&skb->users), n, here);
+		kfree_skb(skb);
 	}
 }