/*

   *  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
   *  and asynchronous requests.
   *
   *  -	RPC header generation and argument serialization.
   *  -	Credential refresh.
   *  -	TCP connect handling.
   *  -	Retry of operation when it is suspected the operation failed because
   *	of uid squashing on the server, or when the credentials were stale
   *	and need to be refreshed, or when a packet was damaged in transit.
   *	This may be have to be moved to the VFS layer.
   *

   *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
   *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
   */
  
  #include <asm/system.h>
  
  #include <linux/module.h>
  #include <linux/types.h>

  #include <linux/kallsyms.h>

  #include <linux/mm.h>

  #include <linux/namei.h>
  #include <linux/mount.h>

  #include <linux/slab.h>

  #include <linux/utsname.h>

  #include <linux/workqueue.h>

  #include <linux/in.h>

  #include <linux/in6.h>

  #include <linux/un.h>

  
  #include <linux/sunrpc/clnt.h>

  #include <linux/sunrpc/rpc_pipe_fs.h>

  #include <linux/sunrpc/metrics.h>

  #include <linux/sunrpc/bc_xprt.h>

  #include "sunrpc.h"

  #ifdef RPC_DEBUG
  # define RPCDBG_FACILITY	RPCDBG_CALL
  #endif

  #define dprint_status(t)					\
  	dprintk("RPC: %5u %s (status %d)
  ", t->tk_pid,		\

  			__func__, t->tk_status)

  /*
   * All RPC clients are linked into this list
   */
  static LIST_HEAD(all_clients);
  static DEFINE_SPINLOCK(rpc_client_lock);

  static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  
  
  static void	call_start(struct rpc_task *task);
  static void	call_reserve(struct rpc_task *task);
  static void	call_reserveresult(struct rpc_task *task);
  static void	call_allocate(struct rpc_task *task);

  static void	call_decode(struct rpc_task *task);
  static void	call_bind(struct rpc_task *task);

  static void	call_bind_status(struct rpc_task *task);

  static void	call_transmit(struct rpc_task *task);

  #if defined(CONFIG_SUNRPC_BACKCHANNEL)

  static void	call_bc_transmit(struct rpc_task *task);

  #endif /* CONFIG_SUNRPC_BACKCHANNEL */

  static void	call_status(struct rpc_task *task);

  static void	call_transmit_status(struct rpc_task *task);

  static void	call_refresh(struct rpc_task *task);
  static void	call_refreshresult(struct rpc_task *task);
  static void	call_timeout(struct rpc_task *task);
  static void	call_connect(struct rpc_task *task);
  static void	call_connect_status(struct rpc_task *task);

  static __be32	*rpc_encode_header(struct rpc_task *task);
  static __be32	*rpc_verify_header(struct rpc_task *task);

  static int	rpc_ping(struct rpc_clnt *clnt);

  static void rpc_register_client(struct rpc_clnt *clnt)
  {
  	spin_lock(&rpc_client_lock);
  	list_add(&clnt->cl_clients, &all_clients);
  	spin_unlock(&rpc_client_lock);
  }
  
  static void rpc_unregister_client(struct rpc_clnt *clnt)
  {
  	spin_lock(&rpc_client_lock);
  	list_del(&clnt->cl_clients);
  	spin_unlock(&rpc_client_lock);
  }

  
  static int
  rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  {

  	static uint32_t clntid;

  	struct path path, dir;

  	char name[15];
  	struct qstr q = {
  		.name = name,
  	};

  	int error;

  	clnt->cl_path.mnt = ERR_PTR(-ENOENT);
  	clnt->cl_path.dentry = ERR_PTR(-ENOENT);

  	if (dir_name == NULL)
  		return 0;

  	path.mnt = rpc_get_mount();
  	if (IS_ERR(path.mnt))
  		return PTR_ERR(path.mnt);

  	error = vfs_path_lookup(path.mnt->mnt_root, path.mnt, dir_name, 0, &dir);

  	if (error)
  		goto err;

  	for (;;) {

  		q.len = snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
  		name[sizeof(name) - 1] = '\0';
  		q.hash = full_name_hash(q.name, q.len);

  		path.dentry = rpc_create_client_dir(dir.dentry, &q, clnt);

  		if (!IS_ERR(path.dentry))
  			break;
  		error = PTR_ERR(path.dentry);

  		if (error != -EEXIST) {

  			printk(KERN_INFO "RPC: Couldn't create pipefs entry"
  					" %s/%s, error %d
  ",
  					dir_name, name, error);
  			goto err_path_put;

  		}

  	}

  	path_put(&dir);

  	clnt->cl_path = path;
  	return 0;
  err_path_put:

  	path_put(&dir);

  err:
  	rpc_put_mount();
  	return error;

  }

  static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)

  {

  	struct rpc_program	*program = args->program;

  	struct rpc_version	*version;
  	struct rpc_clnt		*clnt = NULL;

  	struct rpc_auth		*auth;

  	int err;

  	size_t len;
  
  	/* sanity check the name before trying to print it */
  	err = -EINVAL;

  	len = strlen(args->servername);

  	if (len > RPC_MAXNETNAMELEN)
  		goto out_no_rpciod;
  	len++;

  	dprintk("RPC:       creating %s client for %s (xprt %p)
  ",

  			program->name, args->servername, xprt);

  	err = rpciod_up();
  	if (err)
  		goto out_no_rpciod;

  	err = -EINVAL;
  	if (!xprt)

  		goto out_no_xprt;

  
  	if (args->version >= program->nrvers)
  		goto out_err;
  	version = program->version[args->version];
  	if (version == NULL)

  		goto out_err;
  
  	err = -ENOMEM;

  	clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);

  	if (!clnt)
  		goto out_err;

  	clnt->cl_parent = clnt;
  
  	clnt->cl_server = clnt->cl_inline_name;

  	if (len > sizeof(clnt->cl_inline_name)) {
  		char *buf = kmalloc(len, GFP_KERNEL);

  		if (buf != NULL)

  			clnt->cl_server = buf;
  		else
  			len = sizeof(clnt->cl_inline_name);
  	}

  	strlcpy(clnt->cl_server, args->servername, len);

  
  	clnt->cl_xprt     = xprt;
  	clnt->cl_procinfo = version->procs;
  	clnt->cl_maxproc  = version->nrprocs;
  	clnt->cl_protname = program->name;

  	clnt->cl_prog     = args->prognumber ? : program->number;

  	clnt->cl_vers     = version->number;

  	clnt->cl_stats    = program->stats;

  	clnt->cl_metrics  = rpc_alloc_iostats(clnt);

  	err = -ENOMEM;
  	if (clnt->cl_metrics == NULL)
  		goto out_no_stats;

  	clnt->cl_program  = program;

  	INIT_LIST_HEAD(&clnt->cl_tasks);

  	spin_lock_init(&clnt->cl_lock);

  	if (!xprt_bound(clnt->cl_xprt))

  		clnt->cl_autobind = 1;

  	clnt->cl_timeout = xprt->timeout;
  	if (args->timeout != NULL) {
  		memcpy(&clnt->cl_timeout_default, args->timeout,
  				sizeof(clnt->cl_timeout_default));
  		clnt->cl_timeout = &clnt->cl_timeout_default;
  	}

  	clnt->cl_rtt = &clnt->cl_rtt_default;

  	rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);

  	clnt->cl_principal = NULL;
  	if (args->client_name) {
  		clnt->cl_principal = kstrdup(args->client_name, GFP_KERNEL);
  		if (!clnt->cl_principal)
  			goto out_no_principal;
  	}

  	atomic_set(&clnt->cl_count, 1);

  	err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
  	if (err < 0)
  		goto out_no_path;

  	auth = rpcauth_create(args->authflavor, clnt);

  	if (IS_ERR(auth)) {

  		printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)
  ",

  				args->authflavor);

  		err = PTR_ERR(auth);

  		goto out_no_auth;
  	}
  
  	/* save the nodename */

  	clnt->cl_nodelen = strlen(init_utsname()->nodename);

  	if (clnt->cl_nodelen > UNX_MAXNODENAME)
  		clnt->cl_nodelen = UNX_MAXNODENAME;

  	memcpy(clnt->cl_nodename, init_utsname()->nodename, clnt->cl_nodelen);

  	rpc_register_client(clnt);

  	return clnt;
  
  out_no_auth:

  	if (!IS_ERR(clnt->cl_path.dentry)) {
  		rpc_remove_client_dir(clnt->cl_path.dentry);

  		rpc_put_mount();
  	}

  out_no_path:

  	kfree(clnt->cl_principal);
  out_no_principal:

  	rpc_free_iostats(clnt->cl_metrics);
  out_no_stats:

  	if (clnt->cl_server != clnt->cl_inline_name)
  		kfree(clnt->cl_server);
  	kfree(clnt);
  out_err:

  	xprt_put(xprt);

  out_no_xprt:

  	rpciod_down();
  out_no_rpciod:

  	return ERR_PTR(err);
  }

  /*
   * rpc_create - create an RPC client and transport with one call
   * @args: rpc_clnt create argument structure
   *
   * Creates and initializes an RPC transport and an RPC client.
   *
   * It can ping the server in order to determine if it is up, and to see if
   * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
   * this behavior so asynchronous tasks can also use rpc_create.
   */
  struct rpc_clnt *rpc_create(struct rpc_create_args *args)
  {
  	struct rpc_xprt *xprt;
  	struct rpc_clnt *clnt;

  	struct xprt_create xprtargs = {

  		.net = args->net,

  		.ident = args->protocol,

  		.srcaddr = args->saddress,

  		.dstaddr = args->address,
  		.addrlen = args->addrsize,

  		.bc_xprt = args->bc_xprt,

  	};

  	char servername[48];

  	/*

  	 * If the caller chooses not to specify a hostname, whip
  	 * up a string representation of the passed-in address.
  	 */
  	if (args->servername == NULL) {

  		struct sockaddr_un *sun =
  				(struct sockaddr_un *)args->address;

  		struct sockaddr_in *sin =
  				(struct sockaddr_in *)args->address;
  		struct sockaddr_in6 *sin6 =
  				(struct sockaddr_in6 *)args->address;

  		servername[0] = '\0';
  		switch (args->address->sa_family) {

  		case AF_LOCAL:
  			snprintf(servername, sizeof(servername), "%s",
  				 sun->sun_path);
  			break;

  		case AF_INET:

  			snprintf(servername, sizeof(servername), "%pI4",
  				 &sin->sin_addr.s_addr);

  			break;

  		case AF_INET6:

  			snprintf(servername, sizeof(servername), "%pI6",

  				 &sin6->sin6_addr);

  			break;

  		default:
  			/* caller wants default server name, but
  			 * address family isn't recognized. */
  			return ERR_PTR(-EINVAL);
  		}

  		args->servername = servername;
  	}

  	xprt = xprt_create_transport(&xprtargs);
  	if (IS_ERR(xprt))
  		return (struct rpc_clnt *)xprt;

  	/*

  	 * By default, kernel RPC client connects from a reserved port.
  	 * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
  	 * but it is always enabled for rpciod, which handles the connect
  	 * operation.
  	 */
  	xprt->resvport = 1;
  	if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
  		xprt->resvport = 0;

  	clnt = rpc_new_client(args, xprt);

  	if (IS_ERR(clnt))
  		return clnt;
  
  	if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {

  		int err = rpc_ping(clnt);

  		if (err != 0) {
  			rpc_shutdown_client(clnt);
  			return ERR_PTR(err);
  		}
  	}
  
  	clnt->cl_softrtry = 1;
  	if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
  		clnt->cl_softrtry = 0;

  	if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
  		clnt->cl_autobind = 1;

  	if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
  		clnt->cl_discrtry = 1;

  	if (!(args->flags & RPC_CLNT_CREATE_QUIET))
  		clnt->cl_chatty = 1;

  
  	return clnt;
  }

  EXPORT_SYMBOL_GPL(rpc_create);

  /*
   * This function clones the RPC client structure. It allows us to share the
   * same transport while varying parameters such as the authentication
   * flavour.
   */
  struct rpc_clnt *
  rpc_clone_client(struct rpc_clnt *clnt)
  {
  	struct rpc_clnt *new;

  	int err = -ENOMEM;

  	new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);

  	if (!new)
  		goto out_no_clnt;

  	new->cl_parent = clnt;
  	/* Turn off autobind on clones */
  	new->cl_autobind = 0;
  	INIT_LIST_HEAD(&new->cl_tasks);
  	spin_lock_init(&new->cl_lock);

  	rpc_init_rtt(&new->cl_rtt_default, clnt->cl_timeout->to_initval);

  	new->cl_metrics = rpc_alloc_iostats(clnt);
  	if (new->cl_metrics == NULL)
  		goto out_no_stats;

  	if (clnt->cl_principal) {
  		new->cl_principal = kstrdup(clnt->cl_principal, GFP_KERNEL);
  		if (new->cl_principal == NULL)
  			goto out_no_principal;
  	}

  	atomic_set(&new->cl_count, 1);

  	err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
  	if (err != 0)
  		goto out_no_path;

  	if (new->cl_auth)
  		atomic_inc(&new->cl_auth->au_count);

  	xprt_get(clnt->cl_xprt);

  	atomic_inc(&clnt->cl_count);

  	rpc_register_client(new);

  	rpciod_up();

  	return new;

  out_no_path:

  	kfree(new->cl_principal);
  out_no_principal:

  	rpc_free_iostats(new->cl_metrics);

  out_no_stats:
  	kfree(new);

  out_no_clnt:

  	dprintk("RPC:       %s: returned error %d
  ", __func__, err);

  	return ERR_PTR(err);

  }

  EXPORT_SYMBOL_GPL(rpc_clone_client);

  
  /*

   * Kill all tasks for the given client.
   * XXX: kill their descendants as well?
   */
  void rpc_killall_tasks(struct rpc_clnt *clnt)
  {
  	struct rpc_task	*rovr;
  
  
  	if (list_empty(&clnt->cl_tasks))
  		return;
  	dprintk("RPC:       killing all tasks for client %p
  ", clnt);
  	/*
  	 * Spin lock all_tasks to prevent changes...
  	 */
  	spin_lock(&clnt->cl_lock);
  	list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
  		if (!RPC_IS_ACTIVATED(rovr))
  			continue;
  		if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
  			rovr->tk_flags |= RPC_TASK_KILLED;
  			rpc_exit(rovr, -EIO);

  			if (RPC_IS_QUEUED(rovr))
  				rpc_wake_up_queued_task(rovr->tk_waitqueue,
  							rovr);

  		}
  	}
  	spin_unlock(&clnt->cl_lock);
  }
  EXPORT_SYMBOL_GPL(rpc_killall_tasks);
  
  /*

   * Properly shut down an RPC client, terminating all outstanding

   * requests.

   */

  void rpc_shutdown_client(struct rpc_clnt *clnt)

  {

  	dprintk("RPC:       shutting down %s client for %s
  ",
  			clnt->cl_protname, clnt->cl_server);

  	while (!list_empty(&clnt->cl_tasks)) {

  		rpc_killall_tasks(clnt);

  		wait_event_timeout(destroy_wait,

  			list_empty(&clnt->cl_tasks), 1*HZ);

  	}

  	rpc_release_client(clnt);

  }

  EXPORT_SYMBOL_GPL(rpc_shutdown_client);

  
  /*

   * Free an RPC client

   */

  static void

  rpc_free_client(struct rpc_clnt *clnt)

  {

  	dprintk("RPC:       destroying %s client for %s
  ",

  			clnt->cl_protname, clnt->cl_server);

  	if (!IS_ERR(clnt->cl_path.dentry)) {
  		rpc_remove_client_dir(clnt->cl_path.dentry);

  		rpc_put_mount();
  	}

  	if (clnt->cl_parent != clnt) {

  		rpc_release_client(clnt->cl_parent);

  		goto out_free;
  	}

  	if (clnt->cl_server != clnt->cl_inline_name)
  		kfree(clnt->cl_server);
  out_free:

  	rpc_unregister_client(clnt);

  	rpc_free_iostats(clnt->cl_metrics);

  	kfree(clnt->cl_principal);

  	clnt->cl_metrics = NULL;

  	xprt_put(clnt->cl_xprt);

  	rpciod_down();

  	kfree(clnt);

  }
  
  /*

   * Free an RPC client
   */
  static void

  rpc_free_auth(struct rpc_clnt *clnt)

  {

  	if (clnt->cl_auth == NULL) {

  		rpc_free_client(clnt);

  		return;
  	}
  
  	/*
  	 * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
  	 *       release remaining GSS contexts. This mechanism ensures
  	 *       that it can do so safely.
  	 */

  	atomic_inc(&clnt->cl_count);

  	rpcauth_release(clnt->cl_auth);
  	clnt->cl_auth = NULL;

  	if (atomic_dec_and_test(&clnt->cl_count))
  		rpc_free_client(clnt);

  }
  
  /*

   * Release reference to the RPC client

   */
  void
  rpc_release_client(struct rpc_clnt *clnt)
  {

  	dprintk("RPC:       rpc_release_client(%p)
  ", clnt);

  	if (list_empty(&clnt->cl_tasks))
  		wake_up(&destroy_wait);

  	if (atomic_dec_and_test(&clnt->cl_count))
  		rpc_free_auth(clnt);

  }

  /**
   * rpc_bind_new_program - bind a new RPC program to an existing client

   * @old: old rpc_client
   * @program: rpc program to set
   * @vers: rpc program version

   *
   * Clones the rpc client and sets up a new RPC program. This is mainly
   * of use for enabling different RPC programs to share the same transport.
   * The Sun NFSv2/v3 ACL protocol can do this.
   */
  struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
  				      struct rpc_program *program,

  				      u32 vers)

  {
  	struct rpc_clnt *clnt;
  	struct rpc_version *version;
  	int err;
  
  	BUG_ON(vers >= program->nrvers || !program->version[vers]);
  	version = program->version[vers];
  	clnt = rpc_clone_client(old);
  	if (IS_ERR(clnt))
  		goto out;
  	clnt->cl_procinfo = version->procs;
  	clnt->cl_maxproc  = version->nrprocs;
  	clnt->cl_protname = program->name;
  	clnt->cl_prog     = program->number;
  	clnt->cl_vers     = version->number;
  	clnt->cl_stats    = program->stats;

  	err = rpc_ping(clnt);

  	if (err != 0) {
  		rpc_shutdown_client(clnt);
  		clnt = ERR_PTR(err);
  	}

  out:

  	return clnt;
  }

  EXPORT_SYMBOL_GPL(rpc_bind_new_program);

  void rpc_task_release_client(struct rpc_task *task)
  {
  	struct rpc_clnt *clnt = task->tk_client;
  
  	if (clnt != NULL) {
  		/* Remove from client task list */
  		spin_lock(&clnt->cl_lock);
  		list_del(&task->tk_task);
  		spin_unlock(&clnt->cl_lock);
  		task->tk_client = NULL;
  
  		rpc_release_client(clnt);
  	}
  }
  
  static
  void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
  {
  	if (clnt != NULL) {
  		rpc_task_release_client(task);
  		task->tk_client = clnt;

  		atomic_inc(&clnt->cl_count);

  		if (clnt->cl_softrtry)
  			task->tk_flags |= RPC_TASK_SOFT;
  		/* Add to the client's list of all tasks */
  		spin_lock(&clnt->cl_lock);
  		list_add_tail(&task->tk_task, &clnt->cl_tasks);
  		spin_unlock(&clnt->cl_lock);
  	}
  }

  void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
  {
  	rpc_task_release_client(task);
  	rpc_task_set_client(task, clnt);
  }
  EXPORT_SYMBOL_GPL(rpc_task_reset_client);

  static void
  rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
  {
  	if (msg != NULL) {
  		task->tk_msg.rpc_proc = msg->rpc_proc;
  		task->tk_msg.rpc_argp = msg->rpc_argp;
  		task->tk_msg.rpc_resp = msg->rpc_resp;

  		if (msg->rpc_cred != NULL)
  			task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);

  	}
  }

  /*
   * Default callback for async RPC calls
   */
  static void

  rpc_default_callback(struct rpc_task *task, void *data)

  {
  }

  static const struct rpc_call_ops rpc_default_ops = {
  	.rpc_call_done = rpc_default_callback,
  };

  /**
   * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
   * @task_setup_data: pointer to task initialisation data
   */
  struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)

  {

  	struct rpc_task *task;

  	task = rpc_new_task(task_setup_data);

  	if (IS_ERR(task))

  		goto out;

  	rpc_task_set_client(task, task_setup_data->rpc_client);
  	rpc_task_set_rpc_message(task, task_setup_data->rpc_message);

  	if (task->tk_action == NULL)
  		rpc_call_start(task);

  	atomic_inc(&task->tk_count);
  	rpc_execute(task);

  out:

  	return task;

  }

  EXPORT_SYMBOL_GPL(rpc_run_task);

  
  /**
   * rpc_call_sync - Perform a synchronous RPC call
   * @clnt: pointer to RPC client
   * @msg: RPC call parameters
   * @flags: RPC call flags

   */

  int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)

  {
  	struct rpc_task	*task;

  	struct rpc_task_setup task_setup_data = {
  		.rpc_client = clnt,
  		.rpc_message = msg,
  		.callback_ops = &rpc_default_ops,
  		.flags = flags,
  	};

  	int status;

  	BUG_ON(flags & RPC_TASK_ASYNC);

  	task = rpc_run_task(&task_setup_data);

  	if (IS_ERR(task))
  		return PTR_ERR(task);

  	status = task->tk_status;

  	rpc_put_task(task);

  	return status;
  }

  EXPORT_SYMBOL_GPL(rpc_call_sync);

  /**
   * rpc_call_async - Perform an asynchronous RPC call
   * @clnt: pointer to RPC client
   * @msg: RPC call parameters
   * @flags: RPC call flags

   * @tk_ops: RPC call ops

   * @data: user call data

   */
  int

  rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,

  	       const struct rpc_call_ops *tk_ops, void *data)

  {
  	struct rpc_task	*task;

  	struct rpc_task_setup task_setup_data = {
  		.rpc_client = clnt,
  		.rpc_message = msg,
  		.callback_ops = tk_ops,
  		.callback_data = data,
  		.flags = flags|RPC_TASK_ASYNC,
  	};

  	task = rpc_run_task(&task_setup_data);

  	if (IS_ERR(task))
  		return PTR_ERR(task);
  	rpc_put_task(task);
  	return 0;

  }

  EXPORT_SYMBOL_GPL(rpc_call_async);

  #if defined(CONFIG_SUNRPC_BACKCHANNEL)

  /**
   * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
   * rpc_execute against it

   * @req: RPC request
   * @tk_ops: RPC call ops

   */
  struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,

  				const struct rpc_call_ops *tk_ops)

  {
  	struct rpc_task *task;
  	struct xdr_buf *xbufp = &req->rq_snd_buf;
  	struct rpc_task_setup task_setup_data = {
  		.callback_ops = tk_ops,
  	};
  
  	dprintk("RPC: rpc_run_bc_task req= %p
  ", req);
  	/*
  	 * Create an rpc_task to send the data
  	 */
  	task = rpc_new_task(&task_setup_data);

  	if (IS_ERR(task)) {

  		xprt_free_bc_request(req);
  		goto out;
  	}
  	task->tk_rqstp = req;
  
  	/*
  	 * Set up the xdr_buf length.
  	 * This also indicates that the buffer is XDR encoded already.
  	 */
  	xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
  			xbufp->tail[0].iov_len;
  
  	task->tk_action = call_bc_transmit;
  	atomic_inc(&task->tk_count);
  	BUG_ON(atomic_read(&task->tk_count) != 2);
  	rpc_execute(task);
  
  out:
  	dprintk("RPC: rpc_run_bc_task: task= %p
  ", task);
  	return task;
  }

  #endif /* CONFIG_SUNRPC_BACKCHANNEL */

  void

  rpc_call_start(struct rpc_task *task)
  {
  	task->tk_action = call_start;
  }
  EXPORT_SYMBOL_GPL(rpc_call_start);

  /**
   * rpc_peeraddr - extract remote peer address from clnt's xprt
   * @clnt: RPC client structure
   * @buf: target buffer

   * @bufsize: length of target buffer

   *
   * Returns the number of bytes that are actually in the stored address.
   */
  size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
  {
  	size_t bytes;
  	struct rpc_xprt *xprt = clnt->cl_xprt;
  
  	bytes = sizeof(xprt->addr);
  	if (bytes > bufsize)
  		bytes = bufsize;
  	memcpy(buf, &clnt->cl_xprt->addr, bytes);

  	return xprt->addrlen;

  }

  EXPORT_SYMBOL_GPL(rpc_peeraddr);

  /**
   * rpc_peeraddr2str - return remote peer address in printable format
   * @clnt: RPC client structure
   * @format: address format
   *
   */

  const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
  			     enum rpc_display_format_t format)

  {
  	struct rpc_xprt *xprt = clnt->cl_xprt;

  
  	if (xprt->address_strings[format] != NULL)
  		return xprt->address_strings[format];
  	else
  		return "unprintable";

  }

  EXPORT_SYMBOL_GPL(rpc_peeraddr2str);

  void
  rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
  {
  	struct rpc_xprt *xprt = clnt->cl_xprt;

  	if (xprt->ops->set_buffer_size)
  		xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);

  }

  EXPORT_SYMBOL_GPL(rpc_setbufsize);

  
  /*
   * Return size of largest payload RPC client can support, in bytes
   *
   * For stream transports, this is one RPC record fragment (see RFC
   * 1831), as we don't support multi-record requests yet.  For datagram
   * transports, this is the size of an IP packet minus the IP, UDP, and
   * RPC header sizes.
   */
  size_t rpc_max_payload(struct rpc_clnt *clnt)
  {
  	return clnt->cl_xprt->max_payload;
  }

  EXPORT_SYMBOL_GPL(rpc_max_payload);

  /**
   * rpc_force_rebind - force transport to check that remote port is unchanged
   * @clnt: client to rebind
   *
   */
  void rpc_force_rebind(struct rpc_clnt *clnt)
  {
  	if (clnt->cl_autobind)

  		xprt_clear_bound(clnt->cl_xprt);

  }

  EXPORT_SYMBOL_GPL(rpc_force_rebind);

  /*

   * Restart an (async) RPC call from the call_prepare state.
   * Usually called from within the exit handler.
   */

  int

  rpc_restart_call_prepare(struct rpc_task *task)
  {
  	if (RPC_ASSASSINATED(task))

  		return 0;

  	task->tk_action = call_start;
  	if (task->tk_ops->rpc_call_prepare != NULL)
  		task->tk_action = rpc_prepare_task;

  	return 1;

  }
  EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
  
  /*

   * Restart an (async) RPC call. Usually called from within the
   * exit handler.
   */

  int

  rpc_restart_call(struct rpc_task *task)
  {
  	if (RPC_ASSASSINATED(task))

  		return 0;

  	task->tk_action = call_start;

  	return 1;

  }

  EXPORT_SYMBOL_GPL(rpc_restart_call);

  #ifdef RPC_DEBUG
  static const char *rpc_proc_name(const struct rpc_task *task)
  {
  	const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
  
  	if (proc) {
  		if (proc->p_name)
  			return proc->p_name;
  		else
  			return "NULL";
  	} else
  		return "no proc";
  }
  #endif

  /*
   * 0.  Initial state
   *
   *     Other FSM states can be visited zero or more times, but
   *     this state is visited exactly once for each RPC.
   */
  static void
  call_start(struct rpc_task *task)
  {
  	struct rpc_clnt	*clnt = task->tk_client;

  	dprintk("RPC: %5u call_start %s%d proc %s (%s)
  ", task->tk_pid,

  			clnt->cl_protname, clnt->cl_vers,

  			rpc_proc_name(task),

  			(RPC_IS_ASYNC(task) ? "async" : "sync"));

  
  	/* Increment call count */
  	task->tk_msg.rpc_proc->p_count++;
  	clnt->cl_stats->rpccnt++;
  	task->tk_action = call_reserve;
  }
  
  /*
   * 1.	Reserve an RPC call slot
   */
  static void
  call_reserve(struct rpc_task *task)
  {

  	dprint_status(task);

  	task->tk_status  = 0;
  	task->tk_action  = call_reserveresult;
  	xprt_reserve(task);
  }
  
  /*
   * 1b.	Grok the result of xprt_reserve()
   */
  static void
  call_reserveresult(struct rpc_task *task)
  {
  	int status = task->tk_status;

  	dprint_status(task);

  
  	/*
  	 * After a call to xprt_reserve(), we must have either
  	 * a request slot or else an error status.
  	 */
  	task->tk_status = 0;
  	if (status >= 0) {
  		if (task->tk_rqstp) {

  			task->tk_action = call_refresh;

  			return;
  		}
  
  		printk(KERN_ERR "%s: status=%d, but no request slot, exiting
  ",

  				__func__, status);

  		rpc_exit(task, -EIO);
  		return;
  	}
  
  	/*
  	 * Even though there was an error, we may have acquired
  	 * a request slot somehow.  Make sure not to leak it.
  	 */
  	if (task->tk_rqstp) {
  		printk(KERN_ERR "%s: status=%d, request allocated anyway
  ",

  				__func__, status);

  		xprt_release(task);
  	}
  
  	switch (status) {
  	case -EAGAIN:	/* woken up; retry */
  		task->tk_action = call_reserve;
  		return;
  	case -EIO:	/* probably a shutdown */
  		break;
  	default:
  		printk(KERN_ERR "%s: unrecognized error %d, exiting
  ",

  				__func__, status);

  		break;
  	}
  	rpc_exit(task, status);
  }
  
  /*

   * 2.	Bind and/or refresh the credentials
   */
  static void
  call_refresh(struct rpc_task *task)
  {
  	dprint_status(task);
  
  	task->tk_action = call_refreshresult;
  	task->tk_status = 0;
  	task->tk_client->cl_stats->rpcauthrefresh++;
  	rpcauth_refreshcred(task);
  }
  
  /*
   * 2a.	Process the results of a credential refresh
   */
  static void
  call_refreshresult(struct rpc_task *task)
  {
  	int status = task->tk_status;
  
  	dprint_status(task);
  
  	task->tk_status = 0;

  	task->tk_action = call_refresh;

  	switch (status) {

  	case 0:
  		if (rpcauth_uptodatecred(task))
  			task->tk_action = call_allocate;

  		return;
  	case -ETIMEDOUT:
  		rpc_delay(task, 3*HZ);

  	case -EAGAIN:
  		status = -EACCES;
  		if (!task->tk_cred_retry)
  			break;
  		task->tk_cred_retry--;
  		dprintk("RPC: %5u %s: retry refresh creds
  ",
  				task->tk_pid, __func__);
  		return;

  	}

  	dprintk("RPC: %5u %s: refresh creds failed with error %d
  ",
  				task->tk_pid, __func__, status);
  	rpc_exit(task, status);

  }
  
  /*
   * 2b.	Allocate the buffer. For details, see sched.c:rpc_malloc.

   *	(Note: buffer memory is freed in xprt_release).

   */
  static void
  call_allocate(struct rpc_task *task)
  {

  	unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;

  	struct rpc_rqst *req = task->tk_rqstp;
  	struct rpc_xprt *xprt = task->tk_xprt;

  	struct rpc_procinfo *proc = task->tk_msg.rpc_proc;

  	dprint_status(task);

  	task->tk_status = 0;

  	task->tk_action = call_bind;

  	if (req->rq_buffer)

  		return;

  	if (proc->p_proc != 0) {
  		BUG_ON(proc->p_arglen == 0);
  		if (proc->p_decode != NULL)
  			BUG_ON(proc->p_replen == 0);
  	}

  	/*
  	 * Calculate the size (in quads) of the RPC call
  	 * and reply headers, and convert both values
  	 * to byte sizes.
  	 */
  	req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
  	req->rq_callsize <<= 2;
  	req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
  	req->rq_rcvsize <<= 2;

  	req->rq_buffer = xprt->ops->buf_alloc(task,
  					req->rq_callsize + req->rq_rcvsize);

  	if (req->rq_buffer != NULL)

  		return;

  
  	dprintk("RPC: %5u rpc_buffer allocation failed
  ", task->tk_pid);

  	if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {

  		task->tk_action = call_allocate;

  		rpc_delay(task, HZ>>4);
  		return;
  	}
  
  	rpc_exit(task, -ERESTARTSYS);
  }

  static inline int
  rpc_task_need_encode(struct rpc_task *task)
  {
  	return task->tk_rqstp->rq_snd_buf.len == 0;
  }
  
  static inline void
  rpc_task_force_reencode(struct rpc_task *task)
  {
  	task->tk_rqstp->rq_snd_buf.len = 0;

  	task->tk_rqstp->rq_bytes_sent = 0;

  }

  static inline void
  rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
  {
  	buf->head[0].iov_base = start;
  	buf->head[0].iov_len = len;
  	buf->tail[0].iov_len = 0;
  	buf->page_len = 0;

  	buf->flags = 0;

  	buf->len = 0;
  	buf->buflen = len;
  }

  /*
   * 3.	Encode arguments of an RPC call
   */
  static void

  rpc_xdr_encode(struct rpc_task *task)

  {

  	struct rpc_rqst	*req = task->tk_rqstp;

  	kxdreproc_t	encode;

  	__be32		*p;

  	dprint_status(task);

  	rpc_xdr_buf_init(&req->rq_snd_buf,
  			 req->rq_buffer,
  			 req->rq_callsize);
  	rpc_xdr_buf_init(&req->rq_rcv_buf,
  			 (char *)req->rq_buffer + req->rq_callsize,
  			 req->rq_rcvsize);

  	p = rpc_encode_header(task);
  	if (p == NULL) {
  		printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO
  ");

  		rpc_exit(task, -EIO);
  		return;
  	}

  
  	encode = task->tk_msg.rpc_proc->p_encode;

  	if (encode == NULL)
  		return;
  
  	task->tk_status = rpcauth_wrap_req(task, encode, req, p,
  			task->tk_msg.rpc_argp);

  }
  
  /*
   * 4.	Get the server port number if not yet set
   */
  static void
  call_bind(struct rpc_task *task)
  {

  	struct rpc_xprt *xprt = task->tk_xprt;

  	dprint_status(task);

  	task->tk_action = call_connect;

  	if (!xprt_bound(xprt)) {

  		task->tk_action = call_bind_status;

  		task->tk_timeout = xprt->bind_timeout;

  		xprt->ops->rpcbind(task);

  	}
  }
  
  /*

   * 4a.	Sort out bind result
   */
  static void
  call_bind_status(struct rpc_task *task)
  {

  	int status = -EIO;

  
  	if (task->tk_status >= 0) {

  		dprint_status(task);

  		task->tk_status = 0;
  		task->tk_action = call_connect;
  		return;
  	}
  
  	switch (task->tk_status) {

  	case -ENOMEM:
  		dprintk("RPC: %5u rpcbind out of memory
  ", task->tk_pid);
  		rpc_delay(task, HZ >> 2);

  		goto retry_timeout;

  	case -EACCES:

  		dprintk("RPC: %5u remote rpcbind: RPC program/version "
  				"unavailable
  ", task->tk_pid);

  		/* fail immediately if this is an RPC ping */
  		if (task->tk_msg.rpc_proc->p_proc == 0) {
  			status = -EOPNOTSUPP;
  			break;
  		}

  		if (task->tk_rebind_retry == 0)
  			break;
  		task->tk_rebind_retry--;

  		rpc_delay(task, 3*HZ);

  		goto retry_timeout;

  	case -ETIMEDOUT:

  		dprintk("RPC: %5u rpcbind request timed out
  ",

  				task->tk_pid);

  		goto retry_timeout;

  	case -EPFNOSUPPORT:

  		/* server doesn't support any rpcbind version we know of */

  		dprintk("RPC: %5u unrecognized remote rpcbind service
  ",

  				task->tk_pid);
  		break;
  	case -EPROTONOSUPPORT:

  		dprintk("RPC: %5u remote rpcbind version unavailable, retrying
  ",

  				task->tk_pid);

  		task->tk_status = 0;
  		task->tk_action = call_bind;
  		return;

  	case -ECONNREFUSED:		/* connection problems */
  	case -ECONNRESET:
  	case -ENOTCONN:
  	case -EHOSTDOWN:
  	case -EHOSTUNREACH:
  	case -ENETUNREACH:
  	case -EPIPE:
  		dprintk("RPC: %5u remote rpcbind unreachable: %d
  ",
  				task->tk_pid, task->tk_status);
  		if (!RPC_IS_SOFTCONN(task)) {
  			rpc_delay(task, 5*HZ);
  			goto retry_timeout;
  		}
  		status = task->tk_status;
  		break;

  	default:

  		dprintk("RPC: %5u unrecognized rpcbind error (%d)
  ",

  				task->tk_pid, -task->tk_status);

  	}
  
  	rpc_exit(task, status);
  	return;

  retry_timeout:
  	task->tk_action = call_timeout;

  }
  
  /*
   * 4b.	Connect to the RPC server

   */
  static void
  call_connect(struct rpc_task *task)
  {

  	struct rpc_xprt *xprt = task->tk_xprt;

  	dprintk("RPC: %5u call_connect xprt %p %s connected
  ",

  			task->tk_pid, xprt,
  			(xprt_connected(xprt) ? "is" : "is not"));

  	task->tk_action = call_transmit;
  	if (!xprt_connected(xprt)) {
  		task->tk_action = call_connect_status;
  		if (task->tk_status < 0)
  			return;
  		xprt_connect(task);

  	}

  }
  
  /*

   * 4c.	Sort out connect result

   */
  static void
  call_connect_status(struct rpc_task *task)
  {
  	struct rpc_clnt *clnt = task->tk_client;
  	int status = task->tk_status;

  	dprint_status(task);

  	task->tk_status = 0;

  	if (status >= 0 || status == -EAGAIN) {

  		clnt->cl_stats->netreconn++;
  		task->tk_action = call_transmit;
  		return;
  	}

  	switch (status) {

  		/* if soft mounted, test if we've timed out */
  	case -ETIMEDOUT:
  		task->tk_action = call_timeout;

  		break;
  	default:
  		rpc_exit(task, -EIO);

  	}
  }
  
  /*
   * 5.	Transmit the RPC request, and wait for reply
   */
  static void
  call_transmit(struct rpc_task *task)
  {

  	dprint_status(task);

  
  	task->tk_action = call_status;
  	if (task->tk_status < 0)
  		return;
  	task->tk_status = xprt_prepare_transmit(task);
  	if (task->tk_status != 0)
  		return;

  	task->tk_action = call_transmit_status;

  	/* Encode here so that rpcsec_gss can use correct sequence number. */

  	if (rpc_task_need_encode(task)) {

  		BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);

  		rpc_xdr_encode(task);

  		/* Did the encode result in an error condition? */

  		if (task->tk_status != 0) {
  			/* Was the error nonfatal? */
  			if (task->tk_status == -EAGAIN)
  				rpc_delay(task, HZ >> 4);
  			else
  				rpc_exit(task, task->tk_status);

  			return;

  		}

  	}

  	xprt_transmit(task);
  	if (task->tk_status < 0)
  		return;

  	/*
  	 * On success, ensure that we call xprt_end_transmit() before sleeping
  	 * in order to allow access to the socket to other RPC requests.
  	 */
  	call_transmit_status(task);

  	if (rpc_reply_expected(task))

  		return;
  	task->tk_action = rpc_exit_task;

  	rpc_wake_up_queued_task(&task->tk_xprt->pending, task);

  }
  
  /*
   * 5a.	Handle cleanup after a transmission
   */
  static void
  call_transmit_status(struct rpc_task *task)
  {
  	task->tk_action = call_status;

  
  	/*
  	 * Common case: success.  Force the compiler to put this
  	 * test first.
  	 */
  	if (task->tk_status == 0) {
  		xprt_end_transmit(task);
  		rpc_task_force_reencode(task);
  		return;
  	}

  	switch (task->tk_status) {
  	case -EAGAIN:
  		break;
  	default:

  		dprint_status(task);

  		xprt_end_transmit(task);

  		rpc_task_force_reencode(task);
  		break;

  		/*
  		 * Special cases: if we've been waiting on the
  		 * socket's write_space() callback, or if the
  		 * socket just returned a connection error,
  		 * then hold onto the transport lock.
  		 */
  	case -ECONNREFUSED:

  	case -EHOSTDOWN:
  	case -EHOSTUNREACH:
  	case -ENETUNREACH:

  		if (RPC_IS_SOFTCONN(task)) {
  			xprt_end_transmit(task);
  			rpc_exit(task, task->tk_status);
  			break;
  		}
  	case -ECONNRESET:
  	case -ENOTCONN:

  	case -EPIPE:

  		rpc_task_force_reencode(task);
  	}

  }

  #if defined(CONFIG_SUNRPC_BACKCHANNEL)

  /*
   * 5b.	Send the backchannel RPC reply.  On error, drop the reply.  In
   * addition, disconnect on connectivity errors.
   */
  static void
  call_bc_transmit(struct rpc_task *task)
  {
  	struct rpc_rqst *req = task->tk_rqstp;
  
  	BUG_ON(task->tk_status != 0);
  	task->tk_status = xprt_prepare_transmit(task);
  	if (task->tk_status == -EAGAIN) {
  		/*
  		 * Could not reserve the transport. Try again after the
  		 * transport is released.
  		 */
  		task->tk_status = 0;
  		task->tk_action = call_bc_transmit;
  		return;
  	}
  
  	task->tk_action = rpc_exit_task;
  	if (task->tk_status < 0) {
  		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
  			"error: %d
  ", task->tk_status);
  		return;
  	}
  
  	xprt_transmit(task);
  	xprt_end_transmit(task);
  	dprint_status(task);
  	switch (task->tk_status) {
  	case 0:
  		/* Success */
  		break;
  	case -EHOSTDOWN:
  	case -EHOSTUNREACH:
  	case -ENETUNREACH:
  	case -ETIMEDOUT:
  		/*
  		 * Problem reaching the server.  Disconnect and let the
  		 * forechannel reestablish the connection.  The server will
  		 * have to retransmit the backchannel request and we'll
  		 * reprocess it.  Since these ops are idempotent, there's no
  		 * need to cache our reply at this time.
  		 */
  		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
  			"error: %d
  ", task->tk_status);
  		xprt_conditional_disconnect(task->tk_xprt,
  			req->rq_connect_cookie);
  		break;
  	default:
  		/*
  		 * We were unable to reply and will have to drop the
  		 * request.  The server should reconnect and retransmit.
  		 */
  		BUG_ON(task->tk_status == -EAGAIN);
  		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
  			"error: %d
  ", task->tk_status);
  		break;
  	}
  	rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
  }

  #endif /* CONFIG_SUNRPC_BACKCHANNEL */

  /*
   * 6.	Sort out the RPC call status
   */
  static void
  call_status(struct rpc_task *task)
  {
  	struct rpc_clnt	*clnt = task->tk_client;
  	struct rpc_rqst	*req = task->tk_rqstp;
  	int		status;

  	if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
  		task->tk_status = req->rq_reply_bytes_recvd;

  	dprint_status(task);

  
  	status = task->tk_status;
  	if (status >= 0) {
  		task->tk_action = call_decode;
  		return;
  	}
  
  	task->tk_status = 0;
  	switch(status) {

  	case -EHOSTDOWN:
  	case -EHOSTUNREACH:
  	case -ENETUNREACH:
  		/*
  		 * Delay any retries for 3 seconds, then handle as if it
  		 * were a timeout.
  		 */
  		rpc_delay(task, 3*HZ);

  	case -ETIMEDOUT:
  		task->tk_action = call_timeout;

  		if (task->tk_client->cl_discrtry)

  			xprt_conditional_disconnect(task->tk_xprt,
  					req->rq_connect_cookie);

  		break;

  	case -ECONNRESET:

  	case -ECONNREFUSED:

  		rpc_force_rebind(clnt);

  		rpc_delay(task, 3*HZ);
  	case -EPIPE:
  	case -ENOTCONN:

  		task->tk_action = call_bind;
  		break;
  	case -EAGAIN:
  		task->tk_action = call_transmit;
  		break;
  	case -EIO:
  		/* shutdown or soft timeout */
  		rpc_exit(task, status);
  		break;
  	default:

  		if (clnt->cl_chatty)
  			printk("%s: RPC call returned error %d
  ",

  			       clnt->cl_protname, -status);
  		rpc_exit(task, status);

  	}
  }
  
  /*

   * 6a.	Handle RPC timeout

   * 	We do not release the request slot, so we keep using the
   *	same XID for all retransmits.
   */
  static void
  call_timeout(struct rpc_task *task)
  {
  	struct rpc_clnt	*clnt = task->tk_client;
  
  	if (xprt_adjust_timeout(task->tk_rqstp) == 0) {

  		dprintk("RPC: %5u call_timeout (minor)
  ", task->tk_pid);

  		goto retry;
  	}

  	dprintk("RPC: %5u call_timeout (major)
  ", task->tk_pid);

  	task->tk_timeouts++;

  	if (RPC_IS_SOFTCONN(task)) {
  		rpc_exit(task, -ETIMEDOUT);
  		return;
  	}

  	if (RPC_IS_SOFT(task)) {

  		if (clnt->cl_chatty)
  			printk(KERN_NOTICE "%s: server %s not responding, timed out
  ",

  				clnt->cl_protname, clnt->cl_server);

  		if (task->tk_flags & RPC_TASK_TIMEOUT)
  			rpc_exit(task, -ETIMEDOUT);
  		else
  			rpc_exit(task, -EIO);

  		return;
  	}

  	if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {

  		task->tk_flags |= RPC_CALL_MAJORSEEN;

  		if (clnt->cl_chatty)
  			printk(KERN_NOTICE "%s: server %s not responding, still trying
  ",

  			clnt->cl_protname, clnt->cl_server);
  	}

  	rpc_force_rebind(clnt);

  	/*
  	 * Did our request time out due to an RPCSEC_GSS out-of-sequence
  	 * event? RFC2203 requires the server to drop all such requests.
  	 */
  	rpcauth_invalcred(task);

  
  retry:
  	clnt->cl_stats->rpcretrans++;
  	task->tk_action = call_bind;
  	task->tk_status = 0;
  }
  
  /*
   * 7.	Decode the RPC reply
   */
  static void
  call_decode(struct rpc_task *task)
  {
  	struct rpc_clnt	*clnt = task->tk_client;
  	struct rpc_rqst	*req = task->tk_rqstp;

  	kxdrdproc_t	decode = task->tk_msg.rpc_proc->p_decode;

  	__be32		*p;

  	dprint_status(task);

  	if (task->tk_flags & RPC_CALL_MAJORSEEN) {

  		if (clnt->cl_chatty)
  			printk(KERN_NOTICE "%s: server %s OK
  ",
  				clnt->cl_protname, clnt->cl_server);

  		task->tk_flags &= ~RPC_CALL_MAJORSEEN;
  	}

  	/*
  	 * Ensure that we see all writes made by xprt_complete_rqst()

  	 * before it changed req->rq_reply_bytes_recvd.

  	 */
  	smp_rmb();

  	req->rq_rcv_buf.len = req->rq_private_buf.len;
  
  	/* Check that the softirq receive buffer is valid */
  	WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
  				sizeof(req->rq_rcv_buf)) != 0);

  	if (req->rq_rcv_buf.len < 12) {
  		if (!RPC_IS_SOFT(task)) {
  			task->tk_action = call_bind;
  			clnt->cl_stats->rpcretrans++;
  			goto out_retry;
  		}
  		dprintk("RPC:       %s: too small RPC reply size (%d bytes)
  ",
  				clnt->cl_protname, task->tk_status);
  		task->tk_action = call_timeout;
  		goto out_retry;
  	}

  	p = rpc_verify_header(task);

  	if (IS_ERR(p)) {
  		if (p == ERR_PTR(-EAGAIN))
  			goto out_retry;
  		return;

  	}

  	task->tk_action = rpc_exit_task;

  	if (decode) {

  		task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
  						      task->tk_msg.rpc_resp);

  	}

  	dprintk("RPC: %5u call_decode result %d
  ", task->tk_pid,
  			task->tk_status);

  	return;
  out_retry:

  	task->tk_status = 0;

  	/* Note: rpc_verify_header() may have freed the RPC slot */

  	if (task->tk_rqstp == req) {

  		req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;

  		if (task->tk_client->cl_discrtry)

  			xprt_conditional_disconnect(task->tk_xprt,
  					req->rq_connect_cookie);

  	}

  }

  static __be32 *

  rpc_encode_header(struct rpc_task *task)

  {
  	struct rpc_clnt *clnt = task->tk_client;

  	struct rpc_rqst	*req = task->tk_rqstp;

  	__be32		*p = req->rq_svec[0].iov_base;

  
  	/* FIXME: check buffer size? */

  
  	p = xprt_skip_transport_header(task->tk_xprt, p);

  	*p++ = req->rq_xid;		/* XID */
  	*p++ = htonl(RPC_CALL);		/* CALL */
  	*p++ = htonl(RPC_VERSION);	/* RPC version */
  	*p++ = htonl(clnt->cl_prog);	/* program number */
  	*p++ = htonl(clnt->cl_vers);	/* program version */
  	*p++ = htonl(task->tk_msg.rpc_proc->p_proc);	/* procedure */

  	p = rpcauth_marshcred(task, p);
  	req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
  	return p;

  }

  static __be32 *

  rpc_verify_header(struct rpc_task *task)

  {
  	struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
  	int len = task->tk_rqstp->rq_rcv_buf.len >> 2;

  	__be32	*p = iov->iov_base;
  	u32 n;

  	int error = -EACCES;

  	if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
  		/* RFC-1014 says that the representation of XDR data must be a
  		 * multiple of four bytes
  		 * - if it isn't pointer subtraction in the NFS client may give
  		 *   undefined results
  		 */

  		dprintk("RPC: %5u %s: XDR representation not a multiple of"

  		       " 4 bytes: 0x%x
  ", task->tk_pid, __func__,

  		       task->tk_rqstp->rq_rcv_buf.len);

  		goto out_eio;
  	}

  	if ((len -= 3) < 0)
  		goto out_overflow;

  	p += 1; /* skip XID */

  	if ((n = ntohl(*p++)) != RPC_REPLY) {

  		dprintk("RPC: %5u %s: not an RPC reply: %x
  ",

  			task->tk_pid, __func__, n);

  		goto out_garbage;

  	}

  	if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
  		if (--len < 0)
  			goto out_overflow;
  		switch ((n = ntohl(*p++))) {

  		case RPC_AUTH_ERROR:
  			break;
  		case RPC_MISMATCH:
  			dprintk("RPC: %5u %s: RPC call version mismatch!
  ",
  				task->tk_pid, __func__);
  			error = -EPROTONOSUPPORT;
  			goto out_err;
  		default:
  			dprintk("RPC: %5u %s: RPC call rejected, "
  				"unknown error: %x
  ",
  				task->tk_pid, __func__, n);
  			goto out_eio;

  		}
  		if (--len < 0)
  			goto out_overflow;
  		switch ((n = ntohl(*p++))) {
  		case RPC_AUTH_REJECTEDCRED:
  		case RPC_AUTH_REJECTEDVERF:
  		case RPCSEC_GSS_CREDPROBLEM:
  		case RPCSEC_GSS_CTXPROBLEM:
  			if (!task->tk_cred_retry)
  				break;
  			task->tk_cred_retry--;

  			dprintk("RPC: %5u %s: retry stale creds
  ",

  					task->tk_pid, __func__);

  			rpcauth_invalcred(task);

  			/* Ensure we obtain a new XID! */
  			xprt_release(task);

  			task->tk_action = call_reserve;

  			goto out_retry;

  		case RPC_AUTH_BADCRED:
  		case RPC_AUTH_BADVERF:
  			/* possibly garbled cred/verf? */
  			if (!task->tk_garb_retry)
  				break;
  			task->tk_garb_retry--;

  			dprintk("RPC: %5u %s: retry garbled creds
  ",

  					task->tk_pid, __func__);

  			task->tk_action = call_bind;

  			goto out_retry;

  		case RPC_AUTH_TOOWEAK:

  			printk(KERN_NOTICE "RPC: server %s requires stronger "

  			       "authentication.
  ", task->tk_client->cl_server);

  			break;
  		default:

  			dprintk("RPC: %5u %s: unknown auth error: %x
  ",

  					task->tk_pid, __func__, n);

  			error = -EIO;
  		}

  		dprintk("RPC: %5u %s: call rejected %d
  ",

  				task->tk_pid, __func__, n);

  		goto out_err;
  	}
  	if (!(p = rpcauth_checkverf(task, p))) {