Merge tag 'rxrpc-next-20171018' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

David Howells says:

====================
rxrpc: Add bits for kernel services

Here are some patches that add a few things for kernel services to use:

 (1) Allow service upgrade to be requested and allow the resultant actual
     service ID to be obtained.

 (2) Allow the RTT time of a call to be obtained.

 (3) Allow a kernel service to find out if a call is still alive on a
     server between transmitting a request and getting the reply.

 (4) Allow data transmission to ignore signals if transmission progress is
     being made in reasonable time.  This is also usable by userspace by
     passing MSG_WAITALL to sendmsg()[*].

[*] I'm not sure this is the right interface for this or whether a sockopt
    should be used instead.
====================

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

Documentation/networking/rxrpc.txt

@@ -280,6 +280,18 @@ Interaction with the user of the RxRPC socket:
      nominated by a socket option.
 
 
+Notes on sendmsg:
+
+ (*) MSG_WAITALL can be set to tell sendmsg to ignore signals if the peer is
+     making progress at accepting packets within a reasonable time such that we
+     manage to queue up all the data for transmission.  This requires the
+     client to accept at least one packet per 2*RTT time period.
+
+     If this isn't set, sendmsg() will return immediately, either returning
+     EINTR/ERESTARTSYS if nothing was consumed or returning the amount of data
+     consumed.
+
+
 Notes on recvmsg:
 
  (*) If there's a sequence of data messages belonging to a particular call on
@@ -782,7 +794,9 @@ The kernel interface functions are as follows:
 				struct key *key,
 				unsigned long user_call_ID,
 				s64 tx_total_len,
-				gfp_t gfp);
+				gfp_t gfp,
+				rxrpc_notify_rx_t notify_rx,
+				bool upgrade);
 
      This allocates the infrastructure to make a new RxRPC call and assigns
      call and connection numbers.  The call will be made on the UDP port that
@@ -803,6 +817,13 @@ The kernel interface functions are as follows:
      allows the kernel to encrypt directly to the packet buffers, thereby
      saving a copy.  The value may not be less than -1.
 
+     notify_rx is a pointer to a function to be called when events such as
+     incoming data packets or remote aborts happen.
+
+     upgrade should be set to true if a client operation should request that
+     the server upgrade the service to a better one.  The resultant service ID
+     is returned by rxrpc_kernel_recv_data().
+
      If this function is successful, an opaque reference to the RxRPC call is
      returned.  The caller now holds a reference on this and it must be
      properly ended.
@@ -850,7 +871,8 @@ The kernel interface functions are as follows:
 				   size_t size,
 				   size_t *_offset,
 				   bool want_more,
-				   u32 *_abort)
+				   u32 *_abort,
+				   u16 *_service)
 
       This is used to receive data from either the reply part of a client call
       or the request part of a service call.  buf and size specify how much
@@ -873,6 +895,9 @@ The kernel interface functions are as follows:
       If a remote ABORT is detected, the abort code received will be stored in
       *_abort and ECONNABORTED will be returned.
 
+      The service ID that the call ended up with is returned into *_service.
+      This can be used to see if a call got a service upgrade.
+
  (*) Abort a call.
 
 	void rxrpc_kernel_abort_call(struct socket *sock,
@@ -1020,6 +1045,30 @@ The kernel interface functions are as follows:
 
      It returns 0 if the call was requeued and an error otherwise.
 
+ (*) Get call RTT.
+
+	u64 rxrpc_kernel_get_rtt(struct socket *sock, struct rxrpc_call *call);
+
+     Get the RTT time to the peer in use by a call.  The value returned is in
+     nanoseconds.
+
+ (*) Check call still alive.
+
+	u32 rxrpc_kernel_check_life(struct socket *sock,
+				    struct rxrpc_call *call);
+
+     This returns a number that is updated when ACKs are received from the peer
+     (notably including PING RESPONSE ACKs which we can elicit by sending PING
+     ACKs to see if the call still exists on the server).  The caller should
+     compare the numbers of two calls to see if the call is still alive after
+     waiting for a suitable interval.
+
+     This allows the caller to work out if the server is still contactable and
+     if the call is still alive on the server whilst waiting for the server to
+     process a client operation.
+
+     This function may transmit a PING ACK.
+
 
 =======================
 CONFIGURABLE PARAMETERS

fs/afs/internal.h

@@ -100,6 +100,7 @@ struct afs_call {
 	bool			send_pages;	/* T if data from mapping should be sent */
 	bool			need_attention;	/* T if RxRPC poked us */
 	bool			async;		/* T if asynchronous */
+	bool			upgrade;	/* T to request service upgrade */
 	u16			service_id;	/* RxRPC service ID to call */
 	__be16			port;		/* target UDP port */
 	u32			operation_ID;	/* operation ID for an incoming call */

fs/afs/rxrpc.c

@@ -387,7 +387,8 @@ int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 					 tx_total_len, gfp,
 					 (async ?
 					  afs_wake_up_async_call :
-					  afs_wake_up_call_waiter));
+					  afs_wake_up_call_waiter),
+					 call->upgrade);
 	call->key = NULL;
 	if (IS_ERR(rxcall)) {
 		ret = PTR_ERR(rxcall);
@@ -406,7 +407,7 @@ int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 		      call->request_size);
 	msg.msg_control		= NULL;
 	msg.msg_controllen	= 0;
-	msg.msg_flags		= (call->send_pages ? MSG_MORE : 0);
+	msg.msg_flags		= MSG_WAITALL | (call->send_pages ? MSG_MORE : 0);
 
 	/* We have to change the state *before* sending the last packet as
 	 * rxrpc might give us the reply before it returns from sending the
@@ -443,7 +444,7 @@ error_do_abort:
 		abort_code = 0;
 		offset = 0;
 		rxrpc_kernel_recv_data(afs_socket, rxcall, NULL, 0, &offset,
-				       false, &abort_code);
+				       false, &abort_code, &call->service_id);
 		ret = call->type->abort_to_error(abort_code);
 	}
 error_kill_call:
@@ -471,7 +472,8 @@ static void afs_deliver_to_call(struct afs_call *call)
 			size_t offset = 0;
 			ret = rxrpc_kernel_recv_data(afs_socket, call->rxcall,
 						     NULL, 0, &offset, false,
-						     &call->abort_code);
+						     &call->abort_code,
+						     &call->service_id);
 			trace_afs_recv_data(call, 0, offset, false, ret);
 
 			if (ret == -EINPROGRESS || ret == -EAGAIN)
@@ -536,15 +538,26 @@ call_complete:
  */
 static int afs_wait_for_call_to_complete(struct afs_call *call)
 {
+	signed long rtt2, timeout;
 	int ret;
+	u64 rtt;
+	u32 life, last_life;
 
 	DECLARE_WAITQUEUE(myself, current);
 
 	_enter("");
 
+	rtt = rxrpc_kernel_get_rtt(afs_socket, call->rxcall);
+	rtt2 = nsecs_to_jiffies64(rtt) * 2;
+	if (rtt2 < 2)
+		rtt2 = 2;
+
+	timeout = rtt2;
+	last_life = rxrpc_kernel_check_life(afs_socket, call->rxcall);
+
 	add_wait_queue(&call->waitq, &myself);
 	for (;;) {
-		set_current_state(TASK_INTERRUPTIBLE);
+		set_current_state(TASK_UNINTERRUPTIBLE);
 
 		/* deliver any messages that are in the queue */
 		if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
@@ -554,10 +567,20 @@ static int afs_wait_for_call_to_complete(struct afs_call *call)
 			continue;
 		}
 
-		if (call->state == AFS_CALL_COMPLETE ||
+		if (call->state == AFS_CALL_COMPLETE)
-		    signal_pending(current))
 			break;
-		schedule();
+
+		life = rxrpc_kernel_check_life(afs_socket, call->rxcall);
+		if (timeout == 0 &&
+		    life == last_life && signal_pending(current))
+				break;
+
+		if (life != last_life) {
+			timeout = rtt2;
+			last_life = life;
+		}
+
+		timeout = schedule_timeout(timeout);
 	}
 
 	remove_wait_queue(&call->waitq, &myself);
@@ -851,7 +874,8 @@ int afs_extract_data(struct afs_call *call, void *buf, size_t count,
 
 	ret = rxrpc_kernel_recv_data(afs_socket, call->rxcall,
 				     buf, count, &call->offset,
-				     want_more, &call->abort_code);
+				     want_more, &call->abort_code,
+				     &call->service_id);
 	trace_afs_recv_data(call, count, call->offset, want_more, ret);
 	if (ret == 0 || ret == -EAGAIN)
 		return ret;

include/net/af_rxrpc.h

@@ -49,17 +49,19 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *,
 					   unsigned long,
 					   s64,
 					   gfp_t,
-					   rxrpc_notify_rx_t);
+					   rxrpc_notify_rx_t,
+					   bool);
 int rxrpc_kernel_send_data(struct socket *, struct rxrpc_call *,
 			   struct msghdr *, size_t,
 			   rxrpc_notify_end_tx_t);
 int rxrpc_kernel_recv_data(struct socket *, struct rxrpc_call *,
-			   void *, size_t, size_t *, bool, u32 *);
+			   void *, size_t, size_t *, bool, u32 *, u16 *);
 bool rxrpc_kernel_abort_call(struct socket *, struct rxrpc_call *,
 			     u32, int, const char *);
 void rxrpc_kernel_end_call(struct socket *, struct rxrpc_call *);
 void rxrpc_kernel_get_peer(struct socket *, struct rxrpc_call *,
 			   struct sockaddr_rxrpc *);
+u64 rxrpc_kernel_get_rtt(struct socket *, struct rxrpc_call *);
 int rxrpc_kernel_charge_accept(struct socket *, rxrpc_notify_rx_t,
 			       rxrpc_user_attach_call_t, unsigned long, gfp_t);
 void rxrpc_kernel_set_tx_length(struct socket *, struct rxrpc_call *, s64);
@@ -67,5 +69,6 @@ int rxrpc_kernel_retry_call(struct socket *, struct rxrpc_call *,
 			    struct sockaddr_rxrpc *, struct key *);
 int rxrpc_kernel_check_call(struct socket *, struct rxrpc_call *,
 			    enum rxrpc_call_completion *, u32 *);
+u32 rxrpc_kernel_check_life(struct socket *, struct rxrpc_call *);
 
 #endif /* _NET_RXRPC_H */

net/rxrpc/af_rxrpc.c

@@ -265,6 +265,7 @@ static int rxrpc_listen(struct socket *sock, int backlog)
  * @tx_total_len: Total length of data to transmit during the call (or -1)
  * @gfp: The allocation constraints
  * @notify_rx: Where to send notifications instead of socket queue
+ * @upgrade: Request service upgrade for call
  *
  * Allow a kernel service to begin a call on the nominated socket.  This just
  * sets up all the internal tracking structures and allocates connection and
@@ -279,7 +280,8 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *sock,
 					   unsigned long user_call_ID,
 					   s64 tx_total_len,
 					   gfp_t gfp,
-					   rxrpc_notify_rx_t notify_rx)
+					   rxrpc_notify_rx_t notify_rx,
+					   bool upgrade)
 {
 	struct rxrpc_conn_parameters cp;
 	struct rxrpc_call *call;
@@ -304,6 +306,7 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *sock,
 	cp.key			= key;
 	cp.security_level	= 0;
 	cp.exclusive		= false;
+	cp.upgrade		= upgrade;
 	cp.service_id		= srx->srx_service;
 	call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, tx_total_len,
 				     gfp);
@@ -336,6 +339,25 @@ void rxrpc_kernel_end_call(struct socket *sock, struct rxrpc_call *call)
 }
 EXPORT_SYMBOL(rxrpc_kernel_end_call);
 
+/**
+ * rxrpc_kernel_check_life - Check to see whether a call is still alive
+ * @sock: The socket the call is on
+ * @call: The call to check
+ *
+ * Allow a kernel service to find out whether a call is still alive - ie. we're
+ * getting ACKs from the server.  Returns a number representing the life state
+ * which can be compared to that returned by a previous call.
+ *
+ * If this is a client call, ping ACKs will be sent to the server to find out
+ * whether it's still responsive and whether the call is still alive on the
+ * server.
+ */
+u32 rxrpc_kernel_check_life(struct socket *sock, struct rxrpc_call *call)
+{
+	return call->acks_latest;
+}
+EXPORT_SYMBOL(rxrpc_kernel_check_life);
+
 /**
  * rxrpc_kernel_check_call - Check a call's state
  * @sock: The socket the call is on

net/rxrpc/peer_object.c

@@ -411,3 +411,16 @@ void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
 	*_srx = call->peer->srx;
 }
 EXPORT_SYMBOL(rxrpc_kernel_get_peer);
+
+/**
+ * rxrpc_kernel_get_rtt - Get a call's peer RTT
+ * @sock: The socket on which the call is in progress.
+ * @call: The call to query
+ *
+ * Get the call's peer RTT.
+ */
+u64 rxrpc_kernel_get_rtt(struct socket *sock, struct rxrpc_call *call)
+{
+	return call->peer->rtt;
+}
+EXPORT_SYMBOL(rxrpc_kernel_get_rtt);

net/rxrpc/recvmsg.c

@@ -607,6 +607,7 @@ wait_error:
  * @_offset: The running offset into the buffer.
  * @want_more: True if more data is expected to be read
  * @_abort: Where the abort code is stored if -ECONNABORTED is returned
+ * @_service: Where to store the actual service ID (may be upgraded)
  *
  * Allow a kernel service to receive data and pick up information about the
  * state of a call.  Returns 0 if got what was asked for and there's more
@@ -624,7 +625,7 @@ wait_error:
  */
 int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
 			   void *buf, size_t size, size_t *_offset,
-			   bool want_more, u32 *_abort)
+			   bool want_more, u32 *_abort, u16 *_service)
 {
 	struct iov_iter iter;
 	struct kvec iov;
@@ -680,6 +681,8 @@ int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
 read_phase_complete:
 	ret = 1;
 out:
+	if (_service)
+		*_service = call->service_id;
 	mutex_unlock(&call->user_mutex);
 	_leave(" = %d [%zu,%d]", ret, *_offset, *_abort);
 	return ret;

net/rxrpc/sendmsg.c

@@ -37,13 +37,87 @@ struct rxrpc_send_params {
 	bool			upgrade;	/* If the connection is upgradeable */
 };
 
+/*
+ * Wait for space to appear in the Tx queue or a signal to occur.
+ */
+static int rxrpc_wait_for_tx_window_intr(struct rxrpc_sock *rx,
+					 struct rxrpc_call *call,
+					 long *timeo)
+{
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (call->tx_top - call->tx_hard_ack <
+		    min_t(unsigned int, call->tx_winsize,
+			  call->cong_cwnd + call->cong_extra))
+			return 0;
+
+		if (call->state >= RXRPC_CALL_COMPLETE)
+			return call->error;
+
+		if (signal_pending(current))
+			return sock_intr_errno(*timeo);
+
+		trace_rxrpc_transmit(call, rxrpc_transmit_wait);
+		mutex_unlock(&call->user_mutex);
+		*timeo = schedule_timeout(*timeo);
+		if (mutex_lock_interruptible(&call->user_mutex) < 0)
+			return sock_intr_errno(*timeo);
+	}
+}
+
+/*
+ * Wait for space to appear in the Tx queue uninterruptibly, but with
+ * a timeout of 2*RTT if no progress was made and a signal occurred.
+ */
+static int rxrpc_wait_for_tx_window_nonintr(struct rxrpc_sock *rx,
+					    struct rxrpc_call *call)
+{
+	rxrpc_seq_t tx_start, tx_win;
+	signed long rtt2, timeout;
+	u64 rtt;
+
+	rtt = READ_ONCE(call->peer->rtt);
+	rtt2 = nsecs_to_jiffies64(rtt) * 2;
+	if (rtt2 < 1)
+		rtt2 = 1;
+
+	timeout = rtt2;
+	tx_start = READ_ONCE(call->tx_hard_ack);
+
+	for (;;) {
+		set_current_state(TASK_UNINTERRUPTIBLE);
+
+		tx_win = READ_ONCE(call->tx_hard_ack);
+		if (call->tx_top - tx_win <
+		    min_t(unsigned int, call->tx_winsize,
+			  call->cong_cwnd + call->cong_extra))
+			return 0;
+
+		if (call->state >= RXRPC_CALL_COMPLETE)
+			return call->error;
+
+		if (timeout == 0 &&
+		    tx_win == tx_start && signal_pending(current))
+			return -EINTR;
+
+		if (tx_win != tx_start) {
+			timeout = rtt2;
+			tx_start = tx_win;
+		}
+
+		trace_rxrpc_transmit(call, rxrpc_transmit_wait);
+		timeout = schedule_timeout(timeout);
+	}
+}
+
 /*
  * wait for space to appear in the transmit/ACK window
  * - caller holds the socket locked
  */
 static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
 				    struct rxrpc_call *call,
-				    long *timeo)
+				    long *timeo,
+				    bool waitall)
 {
 	DECLARE_WAITQUEUE(myself, current);
 	int ret;
@@ -53,30 +127,10 @@ static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
 
 	add_wait_queue(&call->waitq, &myself);
 
-	for (;;) {
+	if (waitall)
-		set_current_state(TASK_INTERRUPTIBLE);
+		ret = rxrpc_wait_for_tx_window_nonintr(rx, call);
-		ret = 0;
+	else
-		if (call->tx_top - call->tx_hard_ack <
+		ret = rxrpc_wait_for_tx_window_intr(rx, call, timeo);
-		    min_t(unsigned int, call->tx_winsize,
-			  call->cong_cwnd + call->cong_extra))
-			break;
-		if (call->state >= RXRPC_CALL_COMPLETE) {
-			ret = call->error;
-			break;
-		}
-		if (signal_pending(current)) {
-			ret = sock_intr_errno(*timeo);
-			break;
-		}
-
-		trace_rxrpc_transmit(call, rxrpc_transmit_wait);
-		mutex_unlock(&call->user_mutex);
-		*timeo = schedule_timeout(*timeo);
-		if (mutex_lock_interruptible(&call->user_mutex) < 0) {
-			ret = sock_intr_errno(*timeo);
-			break;
-		}
-	}
 
 	remove_wait_queue(&call->waitq, &myself);
 	set_current_state(TASK_RUNNING);
@@ -254,7 +308,8 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 				if (msg->msg_flags & MSG_DONTWAIT)
 					goto maybe_error;
 				ret = rxrpc_wait_for_tx_window(rx, call,
-							       &timeo);
+							       &timeo,
+							       msg->msg_flags & MSG_WAITALL);
 				if (ret < 0)
 					goto maybe_error;
 			}