[PATCH] RPC: client-side transport switch cleanup

 Clean-up: change some comments to reflect the realities of the new RPC
 transport switch mechanism.  Get rid of unused xprt_receive() prototype.

 Also, organize function prototypes in xprt.h by usage and scope.

 Test-plan:
 Compile kernel with CONFIG_NFS enabled.

 Version: Thu, 11 Aug 2005 16:07:21 -0400

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/sunrpc/xprt.h

@@ -1,5 +1,5 @@
 /*
- *  linux/include/linux/sunrpc/clnt_xprt.h
+ *  linux/include/linux/sunrpc/xprt.h
  *
  *  Declarations for the RPC transport interface.
  *
@@ -150,8 +150,8 @@ struct rpc_xprt {
 	unsigned long		cong;		/* current congestion */
 	unsigned long		cwnd;		/* congestion window */
 
-	unsigned int		rcvsize,	/* socket receive buffer size */
-				sndsize;	/* socket send buffer size */
+	unsigned int		rcvsize,	/* transport rcv buffer size */
+				sndsize;	/* transport send buffer size */
 
 	size_t			max_payload;	/* largest RPC payload size,
 						   in bytes */
@@ -184,12 +184,12 @@ struct rpc_xprt {
 	unsigned long		tcp_copied,	/* copied to request */
 				tcp_flags;
 	/*
-	 * Connection of sockets
+	 * Connection of transports
 	 */
-	struct work_struct	sock_connect;
+	struct work_struct	connect_worker;
 	unsigned short		port;
 	/*
-	 * Disconnection of idle sockets
+	 * Disconnection of idle transports
 	 */
 	struct work_struct	task_cleanup;
 	struct timer_list	timer;
@@ -219,27 +219,36 @@ struct rpc_xprt {
 
 #ifdef __KERNEL__
 
-struct rpc_xprt *	xprt_create_proto(int proto, struct sockaddr_in *addr,
-					struct rpc_timeout *toparms);
-void			xprt_disconnect(struct rpc_xprt *);
-int			xprt_destroy(struct rpc_xprt *);
-void			xprt_set_timeout(struct rpc_timeout *, unsigned int,
-					unsigned long);
-struct rpc_rqst *	xprt_lookup_rqst(struct rpc_xprt *, u32);
-void			xprt_complete_rqst(struct rpc_xprt *,
-					struct rpc_rqst *, int);
-void			xprt_reserve(struct rpc_task *);
-int			xprt_prepare_transmit(struct rpc_task *);
-void			xprt_transmit(struct rpc_task *);
-void			xprt_receive(struct rpc_task *);
-void			xprt_wake_pending_tasks(struct rpc_xprt *, int);
+/*
+ * Transport operations used by ULPs
+ */
+struct rpc_xprt *	xprt_create_proto(int proto, struct sockaddr_in *addr, struct rpc_timeout *to);
+void			xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr);
+
+/*
+ * Generic internal transport functions
+ */
+void			xprt_connect(struct rpc_task *task);
+void			xprt_reserve(struct rpc_task *task);
+int			xprt_prepare_transmit(struct rpc_task *task);
+void			xprt_transmit(struct rpc_task *task);
 int			xprt_adjust_timeout(struct rpc_rqst *req);
-void			xprt_release(struct rpc_task *);
-void			xprt_connect(struct rpc_task *);
-int			xs_setup_udp(struct rpc_xprt *,
-					struct rpc_timeout *);
-int			xs_setup_tcp(struct rpc_xprt *,
-					struct rpc_timeout *);
+void			xprt_release(struct rpc_task *task);
+int			xprt_destroy(struct rpc_xprt *xprt);
+
+/*
+ * Transport switch helper functions
+ */
+void			xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
+struct rpc_rqst *	xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid);
+void			xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied);
+void			xprt_disconnect(struct rpc_xprt *xprt);
+
+/*
+ * Socket transport setup operations
+ */
+int			xs_setup_udp(struct rpc_xprt *xprt, struct rpc_timeout *to);
+int			xs_setup_tcp(struct rpc_xprt *xprt, struct rpc_timeout *to);
 
 /*
  * Reserved bit positions in xprt->state

net/sunrpc/clnt.c

@@ -1,5 +1,5 @@
 /*
- *  linux/net/sunrpc/rpcclnt.c
+ *  linux/net/sunrpc/clnt.c
  *
  *  This file contains the high-level RPC interface.
  *  It is modeled as a finite state machine to support both synchronous

net/sunrpc/xprt.c

@@ -10,12 +10,12 @@
  *	one is available. Otherwise, it sleeps on the backlog queue
  *	(xprt_reserve).
  *  -	Next, the caller puts together the RPC message, stuffs it into
- *	the request struct, and calls xprt_call().
- *  -	xprt_call transmits the message and installs the caller on the
- *	socket's wait list. At the same time, it installs a timer that
+ *	the request struct, and calls xprt_transmit().
+ *  -	xprt_transmit sends the message and installs the caller on the
+ *	transport's wait list. At the same time, it installs a timer that
  *	is run after the packet's timeout has expired.
  *  -	When a packet arrives, the data_ready handler walks the list of
- *	pending requests for that socket. If a matching XID is found, the
+ *	pending requests for that transport. If a matching XID is found, the
  *	caller is woken up, and the timer removed.
  *  -	When no reply arrives within the timeout interval, the timer is
  *	fired by the kernel and runs xprt_timer(). It either adjusts the
@@ -32,6 +32,8 @@
  *  tasks that rely on callbacks.
  *
  *  Copyright (C) 1995-1997, Olaf Kirch <okir@monad.swb.de>
+ *
+ *  Transport switch API copyright (C) 2005, Chuck Lever <cel@netapp.com>
  */
 
 #include <linux/module.h>
@@ -52,8 +54,6 @@
 # define RPCDBG_FACILITY	RPCDBG_XPRT
 #endif
 
-#define XPRT_MAX_BACKOFF	(8)
-
 /*
  * Local functions
  */
@@ -65,9 +65,9 @@ static int      __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
 static int	xprt_clear_backlog(struct rpc_xprt *xprt);
 
 /*
- * Serialize write access to sockets, in order to prevent different
+ * Serialize write access to transports, in order to prevent different
  * requests from interfering with each other.
- * Also prevents TCP socket connects from colliding with writes.
+ * Also prevents transport connects from colliding with writes.
  */
 static int
 __xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
@@ -91,7 +91,7 @@ __xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
 	clear_bit(XPRT_LOCKED, &xprt->state);
 	smp_mb__after_clear_bit();
 out_sleep:
-	dprintk("RPC: %4d failed to lock socket %p\n", task->tk_pid, xprt);
+	dprintk("RPC: %4d failed to lock transport %p\n", task->tk_pid, xprt);
 	task->tk_timeout = 0;
 	task->tk_status = -EAGAIN;
 	if (req && req->rq_ntrans)
@@ -144,7 +144,7 @@ out_unlock:
 }
 
 /*
- * Releases the socket for use by other requests.
+ * Releases the transport for use by other requests.
  */
 static void
 __xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
@@ -294,8 +294,7 @@ int xprt_adjust_timeout(struct rpc_rqst *req)
 	return status;
 }
 
-static void
-xprt_socket_autoclose(void *args)
+static void xprt_autoclose(void *args)
 {
 	struct rpc_xprt *xprt = (struct rpc_xprt *)args;
 
@@ -329,7 +328,6 @@ xprt_init_autodisconnect(unsigned long data)
 	if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
 		goto out_abort;
 	spin_unlock(&xprt->transport_lock);
-	/* Let keventd close the socket */
 	if (xprt_connecting(xprt))
 		xprt_release_write(xprt, NULL);
 	else
@@ -770,7 +768,7 @@ static struct rpc_xprt *xprt_setup(int proto, struct sockaddr_in *ap, struct rpc
 
 	INIT_LIST_HEAD(&xprt->free);
 	INIT_LIST_HEAD(&xprt->recv);
-	INIT_WORK(&xprt->task_cleanup, xprt_socket_autoclose, xprt);
+	INIT_WORK(&xprt->task_cleanup, xprt_autoclose, xprt);
 	init_timer(&xprt->timer);
 	xprt->timer.function = xprt_init_autodisconnect;
 	xprt->timer.data = (unsigned long) xprt;

net/sunrpc/xprtsock.c

@@ -11,6 +11,8 @@
  * Rewrite of larges part of the code in order to stabilize TCP stuff.
  * Fix behaviour when socket buffer is full.
  *  (C) 1999 Trond Myklebust <trond.myklebust@fys.uio.no>
+ *
+ * IP socket transport implementation, (C) 2005 Chuck Lever <cel@netapp.com>
  */
 
 #include <linux/types.h>
@@ -363,7 +365,7 @@ static void xs_destroy(struct rpc_xprt *xprt)
 {
 	dprintk("RPC:      xs_destroy xprt %p\n", xprt);
 
-	cancel_delayed_work(&xprt->sock_connect);
+	cancel_delayed_work(&xprt->connect_worker);
 	flush_scheduled_work();
 
 	xprt_disconnect(xprt);
@@ -938,11 +940,11 @@ static void xs_connect(struct rpc_task *task)
 	if (!xprt_test_and_set_connecting(xprt)) {
 		if (xprt->sock != NULL) {
 			dprintk("RPC:      xs_connect delayed xprt %p\n", xprt);
-			schedule_delayed_work(&xprt->sock_connect,
+			schedule_delayed_work(&xprt->connect_worker,
 					RPC_REESTABLISH_TIMEOUT);
 		} else {
 			dprintk("RPC:      xs_connect scheduled xprt %p\n", xprt);
-			schedule_work(&xprt->sock_connect);
+			schedule_work(&xprt->connect_worker);
 			/* flush_scheduled_work can sleep... */
 			if (!RPC_IS_ASYNC(task))
 				flush_scheduled_work();
@@ -989,7 +991,7 @@ int xs_setup_udp(struct rpc_xprt *xprt, struct rpc_timeout *to)
 	/* XXX: header size can vary due to auth type, IPv6, etc. */
 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
 
-	INIT_WORK(&xprt->sock_connect, xs_connect_worker, xprt);
+	INIT_WORK(&xprt->connect_worker, xs_connect_worker, xprt);
 
 	xprt->ops = &xs_ops;
 
@@ -1028,7 +1030,7 @@ int xs_setup_tcp(struct rpc_xprt *xprt, struct rpc_timeout *to)
 	xprt->resvport = capable(CAP_NET_BIND_SERVICE) ? 1 : 0;
 	xprt->max_payload = (1U << 31) - 1;
 
-	INIT_WORK(&xprt->sock_connect, xs_connect_worker, xprt);
+	INIT_WORK(&xprt->connect_worker, xs_connect_worker, xprt);
 
 	xprt->ops = &xs_ops;