Merge tag 'rxrpc-rewrite-20160907-1' of...

Merge tag 'rxrpc-rewrite-20160907-1' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

David Howells says:

====================
rxrpc: Overhaul call refcounting

Here's a set of mostly small patches leading up to one big one.

The big patch at the end of the series overhauls how rxrpc_call refcounting
is handled, making it more sane so that calls bound to user IDs are _only_
released from socket operations or kernel API functions.  Further, the
patch stops calls from holding refs on their parent socket - which can
prevent the socket from being cleaned up.

The second largest patch improves the call tracking tracepoint by providing
extra information about the situation in which gets and puts occur.  This
allows distinctions to be drawn between refs held by the socket user ID
tree, refs held by the work queue (to be implemented by a future patch) and
other refs.

The other patches include a couple of cleanups and some simple alterations
to avoid NULL pointer dereferences in the big patch.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/trace/events/rxrpc.h

@@ -17,7 +17,8 @@
 #include <linux/tracepoint.h>
 
 TRACE_EVENT(rxrpc_call,
-	    TP_PROTO(struct rxrpc_call *call, int op, int usage, int nskb,
+	    TP_PROTO(struct rxrpc_call *call, enum rxrpc_call_trace op,
+		     int usage, int nskb,
 		     const void *where, const void *aux),
 
 	    TP_ARGS(call, op, usage, nskb, where, aux),
@@ -42,13 +43,7 @@ TRACE_EVENT(rxrpc_call,
 
 	    TP_printk("c=%p %s u=%d s=%d p=%pSR a=%p",
 		      __entry->call,
-		      (__entry->op == 0 ? "NWc" :
-		       __entry->op == 1 ? "NWs" :
-		       __entry->op == 2 ? "SEE" :
-		       __entry->op == 3 ? "GET" :
-		       __entry->op == 4 ? "Gsb" :
-		       __entry->op == 5 ? "PUT" :
-		       "Psb"),
+		      rxrpc_call_traces[__entry->op],
 		      __entry->usage,
 		      __entry->nskb,
 		      __entry->where,

net/rxrpc/af_rxrpc.c

@@ -294,9 +294,8 @@ EXPORT_SYMBOL(rxrpc_kernel_begin_call);
 void rxrpc_kernel_end_call(struct socket *sock, struct rxrpc_call *call)
 {
 	_enter("%d{%d}", call->debug_id, atomic_read(&call->usage));
-	rxrpc_remove_user_ID(rxrpc_sk(sock->sk), call);
-	rxrpc_purge_queue(&call->knlrecv_queue);
-	rxrpc_put_call(call);
+	rxrpc_release_call(rxrpc_sk(sock->sk), call);
+	rxrpc_put_call(call, rxrpc_call_put);
 }
 EXPORT_SYMBOL(rxrpc_kernel_end_call);
 
@@ -558,6 +557,7 @@ static int rxrpc_create(struct net *net, struct socket *sock, int protocol,
 		return -ENOMEM;
 
 	sock_init_data(sock, sk);
+	sock_set_flag(sk, SOCK_RCU_FREE);
 	sk->sk_state		= RXRPC_UNBOUND;
 	sk->sk_write_space	= rxrpc_write_space;
 	sk->sk_max_ack_backlog	= 0;

net/rxrpc/ar-internal.h

@@ -35,8 +35,6 @@ struct rxrpc_crypt {
 #define rxrpc_queue_delayed_work(WS,D)	\
 	queue_delayed_work(rxrpc_workqueue, (WS), (D))
 
-#define rxrpc_queue_call(CALL)	rxrpc_queue_work(&(CALL)->processor)
-
 struct rxrpc_connection;
 
 /*
@@ -397,7 +395,6 @@ enum rxrpc_call_event {
 	RXRPC_CALL_EV_ACCEPTED,		/* incoming call accepted by userspace app */
 	RXRPC_CALL_EV_SECURED,		/* incoming call's connection is now secure */
 	RXRPC_CALL_EV_POST_ACCEPT,	/* need to post an "accept?" message to the app */
-	RXRPC_CALL_EV_RELEASE,		/* need to release the call's resources */
 };
 
 /*
@@ -417,7 +414,6 @@ enum rxrpc_call_state {
 	RXRPC_CALL_SERVER_SEND_REPLY,	/* - server sending reply */
 	RXRPC_CALL_SERVER_AWAIT_ACK,	/* - server awaiting final ACK */
 	RXRPC_CALL_COMPLETE,		/* - call complete */
-	RXRPC_CALL_DEAD,		/* - call is dead */
 	NR__RXRPC_CALL_STATES
 };
 
@@ -442,12 +438,10 @@ struct rxrpc_call {
 	struct rcu_head		rcu;
 	struct rxrpc_connection	*conn;		/* connection carrying call */
 	struct rxrpc_peer	*peer;		/* Peer record for remote address */
-	struct rxrpc_sock	*socket;	/* socket responsible */
+	struct rxrpc_sock __rcu	*socket;	/* socket responsible */
 	struct timer_list	lifetimer;	/* lifetime remaining on call */
-	struct timer_list	deadspan;	/* reap timer for re-ACK'ing, etc  */
 	struct timer_list	ack_timer;	/* ACK generation timer */
 	struct timer_list	resend_timer;	/* Tx resend timer */
-	struct work_struct	destroyer;	/* call destroyer */
 	struct work_struct	processor;	/* packet processor and ACK generator */
 	rxrpc_notify_rx_t	notify_rx;	/* kernel service Rx notification function */
 	struct list_head	link;		/* link in master call list */
@@ -475,6 +469,7 @@ struct rxrpc_call {
 	atomic_t		skb_count;	/* Outstanding packets on this call */
 	atomic_t		sequence;	/* Tx data packet sequence counter */
 	u16			service_id;	/* service ID */
+	u8			security_ix;	/* Security type */
 	u32			call_id;	/* call ID on connection  */
 	u32			cid;		/* connection ID plus channel index */
 	int			debug_id;	/* debug ID for printks */
@@ -508,6 +503,24 @@ struct rxrpc_call {
 	unsigned long		ackr_window[RXRPC_ACKR_WINDOW_ASZ + 1];
 };
 
+enum rxrpc_call_trace {
+	rxrpc_call_new_client,
+	rxrpc_call_new_service,
+	rxrpc_call_queued,
+	rxrpc_call_queued_ref,
+	rxrpc_call_seen,
+	rxrpc_call_got,
+	rxrpc_call_got_skb,
+	rxrpc_call_got_userid,
+	rxrpc_call_put,
+	rxrpc_call_put_skb,
+	rxrpc_call_put_userid,
+	rxrpc_call_put_noqueue,
+	rxrpc_call__nr_trace
+};
+
+extern const char rxrpc_call_traces[rxrpc_call__nr_trace][4];
+
 #include <trace/events/rxrpc.h>
 
 /*
@@ -539,7 +552,6 @@ void rxrpc_process_call(struct work_struct *);
 extern const char *const rxrpc_call_states[];
 extern const char *const rxrpc_call_completions[];
 extern unsigned int rxrpc_max_call_lifetime;
-extern unsigned int rxrpc_dead_call_expiry;
 extern struct kmem_cache *rxrpc_call_jar;
 extern struct list_head rxrpc_calls;
 extern rwlock_t rxrpc_call_lock;
@@ -552,11 +564,13 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *,
 struct rxrpc_call *rxrpc_incoming_call(struct rxrpc_sock *,
 				       struct rxrpc_connection *,
 				       struct sk_buff *);
-void rxrpc_release_call(struct rxrpc_call *);
+void rxrpc_release_call(struct rxrpc_sock *, struct rxrpc_call *);
 void rxrpc_release_calls_on_socket(struct rxrpc_sock *);
+bool __rxrpc_queue_call(struct rxrpc_call *);
+bool rxrpc_queue_call(struct rxrpc_call *);
 void rxrpc_see_call(struct rxrpc_call *);
-void rxrpc_get_call(struct rxrpc_call *);
-void rxrpc_put_call(struct rxrpc_call *);
+void rxrpc_get_call(struct rxrpc_call *, enum rxrpc_call_trace);
+void rxrpc_put_call(struct rxrpc_call *, enum rxrpc_call_trace);
 void rxrpc_get_call_for_skb(struct rxrpc_call *, struct sk_buff *);
 void rxrpc_put_call_for_skb(struct rxrpc_call *, struct sk_buff *);
 void __exit rxrpc_destroy_all_calls(void);
@@ -720,7 +734,6 @@ static inline void rxrpc_put_connection(struct rxrpc_connection *conn)
 	}
 }
 
-
 static inline bool rxrpc_queue_conn(struct rxrpc_connection *conn)
 {
 	if (!rxrpc_get_connection_maybe(conn))
@@ -817,6 +830,7 @@ extern const char *rxrpc_acks(u8 reason);
 /*
  * output.c
  */
+int rxrpc_send_call_packet(struct rxrpc_call *, u8);
 int rxrpc_send_data_packet(struct rxrpc_connection *, struct sk_buff *);
 
 /*
@@ -862,7 +876,6 @@ extern const struct file_operations rxrpc_connection_seq_fops;
 /*
  * recvmsg.c
  */
-void rxrpc_remove_user_ID(struct rxrpc_sock *, struct rxrpc_call *);
 int rxrpc_recvmsg(struct socket *, struct msghdr *, size_t, int);
 
 /*
@@ -879,7 +892,7 @@ int __init rxrpc_init_security(void);
 void rxrpc_exit_security(void);
 int rxrpc_init_client_conn_security(struct rxrpc_connection *);
 int rxrpc_init_server_conn_security(struct rxrpc_connection *);
- 
+
 /*
  * sendmsg.c
  */

net/rxrpc/call_accept.c

@@ -115,7 +115,7 @@ static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
 
 	write_lock(&rx->call_lock);
 	if (!test_and_set_bit(RXRPC_CALL_INIT_ACCEPT, &call->flags)) {
-		rxrpc_get_call(call);
+		rxrpc_get_call(call, rxrpc_call_got);
 
 		spin_lock(&call->conn->state_lock);
 		if (sp->hdr.securityIndex > 0 &&
@@ -155,7 +155,7 @@ static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
 	_debug("done");
 	read_unlock_bh(&local->services_lock);
 	rxrpc_free_skb(notification);
-	rxrpc_put_call(call);
+	rxrpc_put_call(call, rxrpc_call_put);
 	_leave(" = 0");
 	return 0;
 
@@ -163,14 +163,8 @@ static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
 	_debug("invalid");
 	read_unlock_bh(&local->services_lock);
 
-	read_lock_bh(&call->state_lock);
-	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-	    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
-		rxrpc_get_call(call);
-		rxrpc_queue_call(call);
-	}
-	read_unlock_bh(&call->state_lock);
-	rxrpc_put_call(call);
+	rxrpc_release_call(rx, call);
+	rxrpc_put_call(call, rxrpc_call_put);
 	ret = -ECONNREFUSED;
 error:
 	rxrpc_free_skb(notification);
@@ -236,13 +230,11 @@ void rxrpc_accept_incoming_calls(struct rxrpc_local *local)
 	if (sk_acceptq_is_full(&rx->sk))
 		goto backlog_full;
 	sk_acceptq_added(&rx->sk);
-	sock_hold(&rx->sk);
 	read_unlock_bh(&local->services_lock);
 
 	ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
 	if (ret < 0)
 		sk_acceptq_removed(&rx->sk);
-	sock_put(&rx->sk);
 	switch (ret) {
 	case -ECONNRESET: /* old calls are ignored */
 	case -ECONNABORTED: /* aborted calls are reaborted or ignored */
@@ -333,14 +325,12 @@ struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 	case RXRPC_CALL_COMPLETE:
 		ret = call->error;
 		goto out_release;
-	case RXRPC_CALL_DEAD:
-		ret = -ETIME;
-		goto out_discard;
 	default:
 		BUG();
 	}
 
 	/* formalise the acceptance */
+	rxrpc_get_call(call, rxrpc_call_got_userid);
 	call->notify_rx = notify_rx;
 	call->user_call_ID = user_call_ID;
 	rb_link_node(&call->sock_node, parent, pp);
@@ -349,25 +339,20 @@ struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 		BUG();
 	if (test_and_set_bit(RXRPC_CALL_EV_ACCEPTED, &call->events))
 		BUG();
-	rxrpc_queue_call(call);
 
-	rxrpc_get_call(call);
 	write_unlock_bh(&call->state_lock);
 	write_unlock(&rx->call_lock);
+	rxrpc_queue_call(call);
 	_leave(" = %p{%d}", call, call->debug_id);
 	return call;
 
-	/* if the call is already dying or dead, then we leave the socket's ref
-	 * on it to be released by rxrpc_dead_call_expired() as induced by
-	 * rxrpc_release_call() */
 out_release:
-	_debug("release %p", call);
-	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-	    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
-		rxrpc_queue_call(call);
-out_discard:
 	write_unlock_bh(&call->state_lock);
-	_debug("discard %p", call);
+	write_unlock(&rx->call_lock);
+	_debug("release %p", call);
+	rxrpc_release_call(rx, call);
+	_leave(" = %d", ret);
+	return ERR_PTR(ret);
 out:
 	write_unlock(&rx->call_lock);
 	_leave(" = %d", ret);
@@ -390,8 +375,11 @@ int rxrpc_reject_call(struct rxrpc_sock *rx)
 	write_lock(&rx->call_lock);
 
 	ret = -ENODATA;
-	if (list_empty(&rx->acceptq))
-		goto out;
+	if (list_empty(&rx->acceptq)) {
+		write_unlock(&rx->call_lock);
+		_leave(" = -ENODATA");
+		return -ENODATA;
+	}
 
 	/* dequeue the first call and check it's still valid */
 	call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
@@ -407,30 +395,17 @@ int rxrpc_reject_call(struct rxrpc_sock *rx)
 		if (test_and_set_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events))
 			rxrpc_queue_call(call);
 		ret = 0;
-		goto out_release;
+		break;
 	case RXRPC_CALL_COMPLETE:
 		ret = call->error;
-		goto out_release;
-	case RXRPC_CALL_DEAD:
-		ret = -ETIME;
-		goto out_discard;
+		break;
 	default:
 		BUG();
 	}
 
-	/* if the call is already dying or dead, then we leave the socket's ref
-	 * on it to be released by rxrpc_dead_call_expired() as induced by
-	 * rxrpc_release_call() */
-out_release:
-	_debug("release %p", call);
-	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-	    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
-		rxrpc_queue_call(call);
-out_discard:
 	write_unlock_bh(&call->state_lock);
-	_debug("discard %p", call);
-out:
 	write_unlock(&rx->call_lock);
+	rxrpc_release_call(rx, call);
 	_leave(" = %d", ret);
 	return ret;
 }

net/rxrpc/call_event.c

@@ -811,8 +811,9 @@ static int rxrpc_post_message(struct rxrpc_call *call, u32 mark, u32 error,
 }
 
 /*
- * handle background processing of incoming call packets and ACK / abort
- * generation
+ * Handle background processing of incoming call packets and ACK / abort
+ * generation.  A ref on the call is donated to us by whoever queued the work
+ * item.
  */
 void rxrpc_process_call(struct work_struct *work)
 {
@@ -827,6 +828,7 @@ void rxrpc_process_call(struct work_struct *work)
 	unsigned long bits;
 	__be32 data, pad;
 	size_t len;
+	bool requeue = false;
 	int loop, nbit, ioc, ret, mtu;
 	u32 serial, abort_code = RX_PROTOCOL_ERROR;
 	u8 *acks = NULL;
@@ -838,6 +840,11 @@ void rxrpc_process_call(struct work_struct *work)
 	       call->debug_id, rxrpc_call_states[call->state], call->events,
 	       (jiffies - call->creation_jif) / (HZ / 10));
 
+	if (call->state >= RXRPC_CALL_COMPLETE) {
+		rxrpc_put_call(call, rxrpc_call_put);
+		return;
+	}
+
 	if (!call->conn)
 		goto skip_msg_init;
 
@@ -1088,16 +1095,21 @@ void rxrpc_process_call(struct work_struct *work)
 		spin_lock_bh(&call->lock);
 
 		if (call->state == RXRPC_CALL_SERVER_SECURING) {
+			struct rxrpc_sock *rx;
 			_debug("securing");
-			write_lock(&call->socket->call_lock);
-			if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-			    !test_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
-				_debug("not released");
-				call->state = RXRPC_CALL_SERVER_ACCEPTING;
-				list_move_tail(&call->accept_link,
-					       &call->socket->acceptq);
+			rcu_read_lock();
+			rx = rcu_dereference(call->socket);
+			if (rx) {
+				write_lock(&rx->call_lock);
+				if (!test_bit(RXRPC_CALL_RELEASED, &call->flags)) {
+					_debug("not released");
+					call->state = RXRPC_CALL_SERVER_ACCEPTING;
+					list_move_tail(&call->accept_link,
+						       &rx->acceptq);
+				}
+				write_unlock(&rx->call_lock);
 			}
-			write_unlock(&call->socket->call_lock);
+			rcu_read_unlock();
 			read_lock(&call->state_lock);
 			if (call->state < RXRPC_CALL_COMPLETE)
 				set_bit(RXRPC_CALL_EV_POST_ACCEPT, &call->events);
@@ -1139,11 +1151,6 @@ void rxrpc_process_call(struct work_struct *work)
 		goto maybe_reschedule;
 	}
 
-	if (test_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
-		rxrpc_release_call(call);
-		clear_bit(RXRPC_CALL_EV_RELEASE, &call->events);
-	}
-
 	/* other events may have been raised since we started checking */
 	goto maybe_reschedule;
 
@@ -1209,10 +1216,8 @@ void rxrpc_process_call(struct work_struct *work)
 			     &msg, iov, ioc, len);
 	if (ret < 0) {
 		_debug("sendmsg failed: %d", ret);
-		read_lock_bh(&call->state_lock);
-		if (call->state < RXRPC_CALL_DEAD)
-			rxrpc_queue_call(call);
-		read_unlock_bh(&call->state_lock);
+		if (call->state < RXRPC_CALL_COMPLETE)
+			requeue = true;
 		goto error;
 	}
 
@@ -1245,41 +1250,22 @@ void rxrpc_process_call(struct work_struct *work)
 
 kill_ACKs:
 	del_timer_sync(&call->ack_timer);
-	if (test_and_clear_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events))
-		rxrpc_put_call(call);
 	clear_bit(RXRPC_CALL_EV_ACK, &call->events);
 
 maybe_reschedule:
 	if (call->events || !skb_queue_empty(&call->rx_queue)) {
-		read_lock_bh(&call->state_lock);
-		if (call->state < RXRPC_CALL_DEAD)
-			rxrpc_queue_call(call);
-		read_unlock_bh(&call->state_lock);
-	}
-
-	/* don't leave aborted connections on the accept queue */
-	if (call->state >= RXRPC_CALL_COMPLETE &&
-	    !list_empty(&call->accept_link)) {
-		_debug("X unlinking once-pending call %p { e=%lx f=%lx c=%x }",
-		       call, call->events, call->flags, call->conn->proto.cid);
-
-		read_lock_bh(&call->state_lock);
-		if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-		    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
-			rxrpc_queue_call(call);
-		read_unlock_bh(&call->state_lock);
+		if (call->state < RXRPC_CALL_COMPLETE)
+			requeue = true;
 	}
 
 error:
 	kfree(acks);
 
-	/* because we don't want two CPUs both processing the work item for one
-	 * call at the same time, we use a flag to note when it's busy; however
-	 * this means there's a race between clearing the flag and setting the
-	 * work pending bit and the work item being processed again */
-	if (call->events && !work_pending(&call->processor)) {
+	if ((requeue || call->events) && !work_pending(&call->processor)) {
 		_debug("jumpstart %x", call->conn->proto.cid);
-		rxrpc_queue_call(call);
+		__rxrpc_queue_call(call);
+	} else {
+		rxrpc_put_call(call, rxrpc_call_put);
 	}
 
 	_leave("");

net/rxrpc/conn_client.c

@@ -348,6 +348,7 @@ static int rxrpc_get_client_conn(struct rxrpc_call *call,
 
 	if (cp->exclusive) {
 		call->conn = candidate;
+		call->security_ix = candidate->security_ix;
 		_leave(" = 0 [exclusive %d]", candidate->debug_id);
 		return 0;
 	}
@@ -395,6 +396,7 @@ static int rxrpc_get_client_conn(struct rxrpc_call *call,
 candidate_published:
 	set_bit(RXRPC_CONN_IN_CLIENT_CONNS, &candidate->flags);
 	call->conn = candidate;
+	call->security_ix = candidate->security_ix;
 	spin_unlock(&local->client_conns_lock);
 	_leave(" = 0 [new %d]", candidate->debug_id);
 	return 0;
@@ -412,6 +414,7 @@ static int rxrpc_get_client_conn(struct rxrpc_call *call,
 
 	spin_lock(&conn->channel_lock);
 	call->conn = conn;
+	call->security_ix = conn->security_ix;
 	list_add(&call->chan_wait_link, &conn->waiting_calls);
 	spin_unlock(&conn->channel_lock);
 	_leave(" = 0 [extant %d]", conn->debug_id);

net/rxrpc/input.c

@@ -39,7 +39,7 @@ int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
 			bool force, bool terminal)
 {
 	struct rxrpc_skb_priv *sp;
-	struct rxrpc_sock *rx = call->socket;
+	struct rxrpc_sock *rx;
 	struct sock *sk;
 	int ret;
 
@@ -59,7 +59,15 @@ int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
 		return 0;
 	}
 
+	/* The socket may go away under us */
+	ret = 0;
+	rcu_read_lock();
+	rx = rcu_dereference(call->socket);
+	if (!rx)
+		goto out;
 	sk = &rx->sk;
+	if (sock_flag(sk, SOCK_DEAD))
+		goto out;
 
 	if (!force) {
 		/* cast skb->rcvbuf to unsigned...  It's pointless, but
@@ -78,7 +86,7 @@ int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
 	spin_lock_bh(&sk->sk_receive_queue.lock);
 	if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags) &&
 	    !test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-	    call->socket->sk.sk_state != RXRPC_CLOSE) {
+	    sk->sk_state != RXRPC_CLOSE) {
 		skb->destructor = rxrpc_packet_destructor;
 		skb->dev = NULL;
 		skb->sk = sk;
@@ -104,8 +112,7 @@ int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
 			__skb_queue_tail(&sk->sk_receive_queue, skb);
 			spin_unlock_bh(&sk->sk_receive_queue.lock);
 
-			if (!sock_flag(sk, SOCK_DEAD))
-				sk->sk_data_ready(sk);
+			sk->sk_data_ready(sk);
 		}
 		skb = NULL;
 	} else {
@@ -115,6 +122,7 @@ int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
 
 out:
 	rxrpc_free_skb(skb);
+	rcu_read_unlock();
 
 	_leave(" = %d", ret);
 	return ret;
@@ -198,7 +206,7 @@ static int rxrpc_fast_process_data(struct rxrpc_call *call,
 
 	/* if the packet need security things doing to it, then it goes down
 	 * the slow path */
-	if (call->conn->security_ix)
+	if (call->security_ix)
 		goto enqueue_packet;
 
 	sp->call = call;
@@ -266,7 +274,7 @@ static int rxrpc_fast_process_data(struct rxrpc_call *call,
 	skb_queue_tail(&call->rx_queue, skb);
 	atomic_inc(&call->ackr_not_idle);
 	read_lock(&call->state_lock);
-	if (call->state < RXRPC_CALL_DEAD)
+	if (call->state < RXRPC_CALL_COMPLETE)
 		rxrpc_queue_call(call);
 	read_unlock(&call->state_lock);
 	_leave(" = 0 [queued]");
@@ -357,7 +365,7 @@ void rxrpc_fast_process_packet(struct rxrpc_call *call, struct sk_buff *skb)
 	case RXRPC_PACKET_TYPE_BUSY:
 		_proto("Rx BUSY %%%u", sp->hdr.serial);
 
-		if (rxrpc_conn_is_service(call->conn))
+		if (rxrpc_is_service_call(call))
 			goto protocol_error;
 
 		write_lock_bh(&call->state_lock);
@@ -408,7 +416,7 @@ void rxrpc_fast_process_packet(struct rxrpc_call *call, struct sk_buff *skb)
 	case RXRPC_PACKET_TYPE_ACK:
 		/* ACK processing is done in process context */
 		read_lock_bh(&call->state_lock);
-		if (call->state < RXRPC_CALL_DEAD) {
+		if (call->state < RXRPC_CALL_COMPLETE) {
 			skb_queue_tail(&call->rx_queue, skb);
 			rxrpc_queue_call(call);
 			skb = NULL;
@@ -497,7 +505,8 @@ static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
  * post an incoming packet to the appropriate call/socket to deal with
  * - must get rid of the sk_buff, either by freeing it or by queuing it
  */
-static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
+static void rxrpc_post_packet_to_call(struct rxrpc_connection *conn,
+				      struct rxrpc_call *call,
 				      struct sk_buff *skb)
 {
 	struct rxrpc_skb_priv *sp;
@@ -510,9 +519,6 @@ static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
 
 	read_lock(&call->state_lock);
 	switch (call->state) {
-	case RXRPC_CALL_DEAD:
-		goto dead_call;
-
 	case RXRPC_CALL_COMPLETE:
 		switch (call->completion) {
 		case RXRPC_CALL_LOCALLY_ABORTED:
@@ -524,7 +530,7 @@ static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
 		default:
 			goto dead_call;
 		case RXRPC_CALL_SUCCEEDED:
-			if (rxrpc_conn_is_service(call->conn))
+			if (rxrpc_is_service_call(call))
 				goto dead_call;
 			goto resend_final_ack;
 		}
@@ -537,7 +543,6 @@ static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
 	}
 
 	read_unlock(&call->state_lock);
-	rxrpc_get_call(call);
 
 	if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 	    sp->hdr.flags & RXRPC_JUMBO_PACKET)
@@ -545,12 +550,10 @@ static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
 	else
 		rxrpc_fast_process_packet(call, skb);
 
-	rxrpc_put_call(call);
 	goto done;
 
 resend_final_ack:
 	_debug("final ack again");
-	rxrpc_get_call(call);
 	set_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events);
 	rxrpc_queue_call(call);
 	goto free_unlock;
@@ -558,7 +561,7 @@ static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
 dead_call:
 	if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 		skb->priority = RX_CALL_DEAD;
-		rxrpc_reject_packet(call->conn->params.local, skb);
+		rxrpc_reject_packet(conn->params.local, skb);
 		goto unlock;
 	}
 free_unlock:
@@ -754,7 +757,7 @@ void rxrpc_data_ready(struct sock *sk)
 			goto cant_route_call;
 
 		rxrpc_see_call(call);
-		rxrpc_post_packet_to_call(call, skb);
+		rxrpc_post_packet_to_call(conn, call, skb);
 		goto out_unlock;
 	}
 

net/rxrpc/output.c

@@ -19,6 +19,151 @@
 #include <net/af_rxrpc.h>
 #include "ar-internal.h"
 
+struct rxrpc_pkt_buffer {
+	struct rxrpc_wire_header whdr;
+	union {
+		struct {
+			struct rxrpc_ackpacket ack;
+			u8 acks[255];
+			u8 pad[3];
+		};
+		__be32 abort_code;
+	};
+	struct rxrpc_ackinfo ackinfo;
+};
+
+/*
+ * Fill out an ACK packet.
+ */
+static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
+				 struct rxrpc_pkt_buffer *pkt)
+{
+	u32 mtu, jmax;
+	u8 *ackp = pkt->acks;
+
+	pkt->ack.bufferSpace	= htons(8);
+	pkt->ack.maxSkew	= htons(0);
+	pkt->ack.firstPacket	= htonl(call->rx_data_eaten + 1);
+	pkt->ack.previousPacket	= htonl(call->ackr_prev_seq);
+	pkt->ack.serial		= htonl(call->ackr_serial);
+	pkt->ack.reason		= RXRPC_ACK_IDLE;
+	pkt->ack.nAcks		= 0;
+
+	mtu = call->peer->if_mtu;
+	mtu -= call->peer->hdrsize;
+	jmax = rxrpc_rx_jumbo_max;
+	pkt->ackinfo.rxMTU	= htonl(rxrpc_rx_mtu);
+	pkt->ackinfo.maxMTU	= htonl(mtu);
+	pkt->ackinfo.rwind	= htonl(rxrpc_rx_window_size);
+	pkt->ackinfo.jumbo_max	= htonl(jmax);
+
+	*ackp++ = 0;
+	*ackp++ = 0;
+	*ackp++ = 0;
+	return 3;
+}
+
+/*
+ * Send a final ACK or ABORT call packet.
+ */
+int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type)
+{
+	struct rxrpc_connection *conn = NULL;
+	struct rxrpc_pkt_buffer *pkt;
+	struct msghdr msg;
+	struct kvec iov[2];
+	rxrpc_serial_t serial;
+	size_t len, n;
+	int ioc, ret;
+	u32 abort_code;
+
+	_enter("%u,%s", call->debug_id, rxrpc_pkts[type]);
+
+	spin_lock_bh(&call->lock);
+	if (call->conn)
+		conn = rxrpc_get_connection_maybe(call->conn);
+	spin_unlock_bh(&call->lock);
+	if (!conn)
+		return -ECONNRESET;
+
+	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+	if (!pkt) {
+		rxrpc_put_connection(conn);
+		return -ENOMEM;
+	}
+
+	serial = atomic_inc_return(&conn->serial);
+
+	msg.msg_name	= &call->peer->srx.transport;
+	msg.msg_namelen	= call->peer->srx.transport_len;
+	msg.msg_control	= NULL;
+	msg.msg_controllen = 0;
+	msg.msg_flags	= 0;
+
+	pkt->whdr.epoch		= htonl(conn->proto.epoch);
+	pkt->whdr.cid		= htonl(call->cid);
+	pkt->whdr.callNumber	= htonl(call->call_id);
+	pkt->whdr.seq		= 0;
+	pkt->whdr.serial	= htonl(serial);
+	pkt->whdr.type		= type;
+	pkt->whdr.flags		= conn->out_clientflag;
+	pkt->whdr.userStatus	= 0;
+	pkt->whdr.securityIndex	= call->security_ix;
+	pkt->whdr._rsvd		= 0;
+	pkt->whdr.serviceId	= htons(call->service_id);
+
+	iov[0].iov_base	= pkt;
+	iov[0].iov_len	= sizeof(pkt->whdr);
+	len = sizeof(pkt->whdr);
+
+	switch (type) {
+	case RXRPC_PACKET_TYPE_ACK:
+		spin_lock_bh(&call->lock);
+		n = rxrpc_fill_out_ack(call, pkt);
+		call->ackr_reason = 0;
+
+		spin_unlock_bh(&call->lock);
+
+		_proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
+		       serial,
+		       ntohs(pkt->ack.maxSkew),
+		       ntohl(pkt->ack.firstPacket),
+		       ntohl(pkt->ack.previousPacket),
+		       ntohl(pkt->ack.serial),
+		       rxrpc_acks(pkt->ack.reason),
+		       pkt->ack.nAcks);
+
+		iov[0].iov_len += sizeof(pkt->ack) + n;
+		iov[1].iov_base = &pkt->ackinfo;
+		iov[1].iov_len	= sizeof(pkt->ackinfo);
+		len += sizeof(pkt->ack) + n + sizeof(pkt->ackinfo);
+		ioc = 2;
+		break;
+
+	case RXRPC_PACKET_TYPE_ABORT:
+		abort_code = call->abort_code;
+		pkt->abort_code = htonl(abort_code);
+		_proto("Tx ABORT %%%u { %d }", serial, abort_code);
+		iov[0].iov_len += sizeof(pkt->abort_code);
+		len += sizeof(pkt->abort_code);
+		ioc = 1;
+		break;
+
+	default:
+		BUG();
+		ret = -ENOANO;
+		goto out;
+	}
+
+	ret = kernel_sendmsg(conn->params.local->socket,
+			     &msg, iov, ioc, len);
+
+out:
+	rxrpc_put_connection(conn);
+	kfree(pkt);
+	return ret;
+}
+
 /*
  * send a packet through the transport endpoint
  */

net/rxrpc/proc.c

@@ -29,6 +29,7 @@ static const char *const rxrpc_conn_states[RXRPC_CONN__NR_STATES] = {
  */
 static void *rxrpc_call_seq_start(struct seq_file *seq, loff_t *_pos)
 {
+	rcu_read_lock();
 	read_lock(&rxrpc_call_lock);
 	return seq_list_start_head(&rxrpc_calls, *_pos);
 }
@@ -41,6 +42,7 @@ static void *rxrpc_call_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 static void rxrpc_call_seq_stop(struct seq_file *seq, void *v)
 {
 	read_unlock(&rxrpc_call_lock);
+	rcu_read_unlock();
 }
 
 static int rxrpc_call_seq_show(struct seq_file *seq, void *v)
@@ -61,7 +63,7 @@ static int rxrpc_call_seq_show(struct seq_file *seq, void *v)
 
 	call = list_entry(v, struct rxrpc_call, link);
 
-	rx = READ_ONCE(call->socket);
+	rx = rcu_dereference(call->socket);
 	if (rx) {
 		local = READ_ONCE(rx->local);
 		if (local)

net/rxrpc/recvmsg.c

@@ -18,28 +18,6 @@
 #include <net/af_rxrpc.h>
 #include "ar-internal.h"
 
-/*
- * removal a call's user ID from the socket tree to make the user ID available
- * again and so that it won't be seen again in association with that call
- */
-void rxrpc_remove_user_ID(struct rxrpc_sock *rx, struct rxrpc_call *call)
-{
-	_debug("RELEASE CALL %d", call->debug_id);
-
-	if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
-		write_lock_bh(&rx->call_lock);
-		rb_erase(&call->sock_node, &call->socket->calls);
-		clear_bit(RXRPC_CALL_HAS_USERID, &call->flags);
-		write_unlock_bh(&rx->call_lock);
-	}
-
-	read_lock_bh(&call->state_lock);
-	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-	    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
-		rxrpc_queue_call(call);
-	read_unlock_bh(&call->state_lock);
-}
-
 /*
  * receive a message from an RxRPC socket
  * - we need to be careful about two or more threads calling recvmsg
@@ -79,7 +57,8 @@ int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 			if (rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
 				release_sock(&rx->sk);
 				if (continue_call)
-					rxrpc_put_call(continue_call);
+					rxrpc_put_call(continue_call,
+						       rxrpc_call_put);
 				return -ENODATA;
 			}
 		}
@@ -137,13 +116,13 @@ int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 			if (call != continue_call ||
 			    skb->mark != RXRPC_SKB_MARK_DATA) {
 				release_sock(&rx->sk);
-				rxrpc_put_call(continue_call);
+				rxrpc_put_call(continue_call, rxrpc_call_put);
 				_leave(" = %d [noncont]", copied);
 				return copied;
 			}
 		}
 
-		rxrpc_get_call(call);
+		rxrpc_get_call(call, rxrpc_call_got);
 
 		/* copy the peer address and timestamp */
 		if (!continue_call) {
@@ -233,7 +212,7 @@ int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 		if (!continue_call)
 			continue_call = sp->call;
 		else
-			rxrpc_put_call(call);
+			rxrpc_put_call(call, rxrpc_call_put);
 		call = NULL;
 
 		if (flags & MSG_PEEK) {
@@ -255,9 +234,9 @@ int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 out:
 	release_sock(&rx->sk);
 	if (call)
-		rxrpc_put_call(call);
+		rxrpc_put_call(call, rxrpc_call_put);
 	if (continue_call)
-		rxrpc_put_call(continue_call);
+		rxrpc_put_call(continue_call, rxrpc_call_put);
 	_leave(" = %d [data]", copied);
 	return copied;
 
@@ -337,22 +316,22 @@ int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 		if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
 			BUG();
 		rxrpc_free_skb(skb);
-		rxrpc_remove_user_ID(rx, call);
+		rxrpc_release_call(rx, call);
 	}
 
 	release_sock(&rx->sk);
-	rxrpc_put_call(call);
+	rxrpc_put_call(call, rxrpc_call_put);
 	if (continue_call)
-		rxrpc_put_call(continue_call);
+		rxrpc_put_call(continue_call, rxrpc_call_put);
 	_leave(" = %d", ret);
 	return ret;
 
 copy_error:
 	_debug("copy error");
 	release_sock(&rx->sk);
-	rxrpc_put_call(call);
+	rxrpc_put_call(call, rxrpc_call_put);
 	if (continue_call)
-		rxrpc_put_call(continue_call);
+		rxrpc_put_call(continue_call, rxrpc_call_put);
 	_leave(" = %d", ret);
 	return ret;
 
@@ -361,7 +340,7 @@ int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 wait_error:
 	finish_wait(sk_sleep(&rx->sk), &wait);
 	if (continue_call)
-		rxrpc_put_call(continue_call);
+		rxrpc_put_call(continue_call, rxrpc_call_put);
 	if (copied)
 		copied = ret;
 	_leave(" = %d [waitfail %d]", copied, ret);

net/rxrpc/sendmsg.c

@@ -322,7 +322,7 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 			sp->hdr.serial	= atomic_inc_return(&conn->serial);
 			sp->hdr.type	= RXRPC_PACKET_TYPE_DATA;
 			sp->hdr.userStatus = 0;
-			sp->hdr.securityIndex = conn->security_ix;
+			sp->hdr.securityIndex = call->security_ix;
 			sp->hdr._rsvd	= 0;
 			sp->hdr.serviceId = call->service_id;
 
@@ -534,7 +534,7 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 		call = rxrpc_accept_call(rx, user_call_ID, NULL);
 		if (IS_ERR(call))
 			return PTR_ERR(call);
-		rxrpc_put_call(call);
+		rxrpc_put_call(call, rxrpc_call_put);
 		return 0;
 	}
 
@@ -573,7 +573,7 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 		ret = rxrpc_send_data(rx, call, msg, len);
 	}
 
-	rxrpc_put_call(call);
+	rxrpc_put_call(call, rxrpc_call_put);
 	_leave(" = %d", ret);
 	return ret;
 }

net/rxrpc/skbuff.c

@@ -33,9 +33,6 @@ static void rxrpc_request_final_ACK(struct rxrpc_call *call)
 		call->state = RXRPC_CALL_CLIENT_FINAL_ACK;
 		_debug("request final ACK");
 
-		/* get an extra ref on the call for the final-ACK generator to
-		 * release */
-		rxrpc_get_call(call);
 		set_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events);
 		if (try_to_del_timer_sync(&call->ack_timer) >= 0)
 			rxrpc_queue_call(call);
@@ -148,19 +145,6 @@ void rxrpc_packet_destructor(struct sk_buff *skb)
 	_leave("");
 }
 
-/**
- * rxrpc_kernel_free_skb - Free an RxRPC socket buffer
- * @skb: The socket buffer to be freed
- *
- * Let RxRPC free its own socket buffer, permitting it to maintain debug
- * accounting.
- */
-void rxrpc_kernel_free_skb(struct sk_buff *skb)
-{
-	rxrpc_free_skb(skb);
-}
-EXPORT_SYMBOL(rxrpc_kernel_free_skb);
-
 /*
  * Note the existence of a new-to-us socket buffer (allocated or dequeued).
  */

net/rxrpc/sysctl.c

@@ -88,14 +88,6 @@ static struct ctl_table rxrpc_sysctl_table[] = {
 		.proc_handler	= proc_dointvec_jiffies,
 		.extra1		= (void *)&one,
 	},
-	{
-		.procname	= "dead_call_expiry",
-		.data		= &rxrpc_dead_call_expiry,
-		.maxlen		= sizeof(unsigned int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_jiffies,
-		.extra1		= (void *)&one,
-	},
 
 	/* Non-time values */
 	{