headers: utsname.h redux
[safe/jmp/linux-2.6] / net / sunrpc / xprt.c
index 269f217..fd46d42 100644 (file)
  *     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
- *     is run after the packet's timeout has expired.
+ *     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, if a reply is expected,
+ *     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
  *
  *  Copyright (C) 1995-1997, Olaf Kirch <okir@monad.swb.de>
  *
- *  TCP callback races fixes (C) 1998 Red Hat Software <alan@redhat.com>
- *  TCP send fixes (C) 1998 Red Hat Software <alan@redhat.com>
- *  TCP NFS related read + write fixes
- *   (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
- *
- *  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>
+ *  Transport switch API copyright (C) 2005, Chuck Lever <cel@netapp.com>
  */
 
+#include <linux/module.h>
+
 #include <linux/types.h>
-#include <linux/slab.h>
-#include <linux/capability.h>
-#include <linux/sched.h>
-#include <linux/errno.h>
-#include <linux/socket.h>
-#include <linux/in.h>
+#include <linux/interrupt.h>
+#include <linux/workqueue.h>
 #include <linux/net.h>
-#include <linux/mm.h>
-#include <linux/udp.h>
-#include <linux/tcp.h>
+
 #include <linux/sunrpc/clnt.h>
-#include <linux/file.h>
-#include <linux/workqueue.h>
-#include <linux/random.h>
+#include <linux/sunrpc/metrics.h>
 
-#include <net/sock.h>
-#include <net/checksum.h>
-#include <net/udp.h>
-#include <net/tcp.h>
+#include "sunrpc.h"
 
 /*
  * Local variables
  */
 
 #ifdef RPC_DEBUG
-# undef  RPC_DEBUG_DATA
 # define RPCDBG_FACILITY       RPCDBG_XPRT
 #endif
 
-#define XPRT_MAX_BACKOFF       (8)
-#define XPRT_IDLE_TIMEOUT      (5*60*HZ)
-#define XPRT_MAX_RESVPORT      (800)
-
 /*
  * Local functions
  */
 static void    xprt_request_init(struct rpc_task *, struct rpc_xprt *);
 static inline void     do_xprt_reserve(struct rpc_task *);
-static void    xprt_disconnect(struct rpc_xprt *);
 static void    xprt_connect_status(struct rpc_task *task);
-static struct rpc_xprt * xprt_setup(int proto, struct sockaddr_in *ap,
-                                               struct rpc_timeout *to);
-static struct socket *xprt_create_socket(struct rpc_xprt *, int, int);
-static void    xprt_bind_socket(struct rpc_xprt *, struct socket *);
 static int      __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
 
-static int     xprt_clear_backlog(struct rpc_xprt *xprt);
+static DEFINE_SPINLOCK(xprt_list_lock);
+static LIST_HEAD(xprt_list);
 
-#ifdef RPC_DEBUG_DATA
 /*
- * Print the buffer contents (first 128 bytes only--just enough for
- * diropres return).
+ * The transport code maintains an estimate on the maximum number of out-
+ * standing RPC requests, using a smoothed version of the congestion
+ * avoidance implemented in 44BSD. This is basically the Van Jacobson
+ * congestion algorithm: If a retransmit occurs, the congestion window is
+ * halved; otherwise, it is incremented by 1/cwnd when
+ *
+ *     -       a reply is received and
+ *     -       a full number of requests are outstanding and
+ *     -       the congestion window hasn't been updated recently.
  */
-static void
-xprt_pktdump(char *msg, u32 *packet, unsigned int count)
+#define RPC_CWNDSHIFT          (8U)
+#define RPC_CWNDSCALE          (1U << RPC_CWNDSHIFT)
+#define RPC_INITCWND           RPC_CWNDSCALE
+#define RPC_MAXCWND(xprt)      ((xprt)->max_reqs << RPC_CWNDSHIFT)
+
+#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
+
+/**
+ * xprt_register_transport - register a transport implementation
+ * @transport: transport to register
+ *
+ * If a transport implementation is loaded as a kernel module, it can
+ * call this interface to make itself known to the RPC client.
+ *
+ * Returns:
+ * 0:          transport successfully registered
+ * -EEXIST:    transport already registered
+ * -EINVAL:    transport module being unloaded
+ */
+int xprt_register_transport(struct xprt_class *transport)
 {
-       u8      *buf = (u8 *) packet;
-       int     j;
-
-       dprintk("RPC:      %s\n", msg);
-       for (j = 0; j < count && j < 128; j += 4) {
-               if (!(j & 31)) {
-                       if (j)
-                               dprintk("\n");
-                       dprintk("0x%04x ", j);
-               }
-               dprintk("%02x%02x%02x%02x ",
-                       buf[j], buf[j+1], buf[j+2], buf[j+3]);
+       struct xprt_class *t;
+       int result;
+
+       result = -EEXIST;
+       spin_lock(&xprt_list_lock);
+       list_for_each_entry(t, &xprt_list, list) {
+               /* don't register the same transport class twice */
+               if (t->ident == transport->ident)
+                       goto out;
        }
-       dprintk("\n");
+
+       list_add_tail(&transport->list, &xprt_list);
+       printk(KERN_INFO "RPC: Registered %s transport module.\n",
+              transport->name);
+       result = 0;
+
+out:
+       spin_unlock(&xprt_list_lock);
+       return result;
 }
-#else
-static inline void
-xprt_pktdump(char *msg, u32 *packet, unsigned int count)
+EXPORT_SYMBOL_GPL(xprt_register_transport);
+
+/**
+ * xprt_unregister_transport - unregister a transport implementation
+ * @transport: transport to unregister
+ *
+ * Returns:
+ * 0:          transport successfully unregistered
+ * -ENOENT:    transport never registered
+ */
+int xprt_unregister_transport(struct xprt_class *transport)
 {
-       /* NOP */
+       struct xprt_class *t;
+       int result;
+
+       result = 0;
+       spin_lock(&xprt_list_lock);
+       list_for_each_entry(t, &xprt_list, list) {
+               if (t == transport) {
+                       printk(KERN_INFO
+                               "RPC: Unregistered %s transport module.\n",
+                               transport->name);
+                       list_del_init(&transport->list);
+                       goto out;
+               }
+       }
+       result = -ENOENT;
+
+out:
+       spin_unlock(&xprt_list_lock);
+       return result;
 }
-#endif
+EXPORT_SYMBOL_GPL(xprt_unregister_transport);
 
-/*
- * Look up RPC transport given an INET socket
+/**
+ * xprt_load_transport - load a transport implementation
+ * @transport_name: transport to load
+ *
+ * Returns:
+ * 0:          transport successfully loaded
+ * -ENOENT:    transport module not available
  */
-static inline struct rpc_xprt *
-xprt_from_sock(struct sock *sk)
+int xprt_load_transport(const char *transport_name)
 {
-       return (struct rpc_xprt *) sk->sk_user_data;
+       struct xprt_class *t;
+       char module_name[sizeof t->name + 5];
+       int result;
+
+       result = 0;
+       spin_lock(&xprt_list_lock);
+       list_for_each_entry(t, &xprt_list, list) {
+               if (strcmp(t->name, transport_name) == 0) {
+                       spin_unlock(&xprt_list_lock);
+                       goto out;
+               }
+       }
+       spin_unlock(&xprt_list_lock);
+       strcpy(module_name, "xprt");
+       strncat(module_name, transport_name, sizeof t->name);
+       result = request_module(module_name);
+out:
+       return result;
 }
+EXPORT_SYMBOL_GPL(xprt_load_transport);
 
-/*
- * Serialize write access to sockets, in order to prevent different
- * requests from interfering with each other.
- * Also prevents TCP socket connects from colliding with writes.
+/**
+ * xprt_reserve_xprt - serialize write access to transports
+ * @task: task that is requesting access to the transport
+ *
+ * This prevents mixing the payload of separate requests, and prevents
+ * transport connects from colliding with writes.  No congestion control
+ * is provided.
  */
-static int
-__xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
+int xprt_reserve_xprt(struct rpc_task *task)
 {
        struct rpc_rqst *req = task->tk_rqstp;
+       struct rpc_xprt *xprt = req->rq_xprt;
 
-       if (test_and_set_bit(XPRT_LOCKED, &xprt->sockstate)) {
+       if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
                if (task == xprt->snd_task)
                        return 1;
                if (task == NULL)
                        return 0;
                goto out_sleep;
        }
-       if (xprt->nocong || __xprt_get_cong(xprt, task)) {
+       xprt->snd_task = task;
+       if (req) {
+               req->rq_bytes_sent = 0;
+               req->rq_ntrans++;
+       }
+       return 1;
+
+out_sleep:
+       dprintk("RPC: %5u failed to lock transport %p\n",
+                       task->tk_pid, xprt);
+       task->tk_timeout = 0;
+       task->tk_status = -EAGAIN;
+       if (req && req->rq_ntrans)
+               rpc_sleep_on(&xprt->resend, task, NULL);
+       else
+               rpc_sleep_on(&xprt->sending, task, NULL);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(xprt_reserve_xprt);
+
+static void xprt_clear_locked(struct rpc_xprt *xprt)
+{
+       xprt->snd_task = NULL;
+       if (!test_bit(XPRT_CLOSE_WAIT, &xprt->state) || xprt->shutdown) {
+               smp_mb__before_clear_bit();
+               clear_bit(XPRT_LOCKED, &xprt->state);
+               smp_mb__after_clear_bit();
+       } else
+               queue_work(rpciod_workqueue, &xprt->task_cleanup);
+}
+
+/*
+ * xprt_reserve_xprt_cong - serialize write access to transports
+ * @task: task that is requesting access to the transport
+ *
+ * Same as xprt_reserve_xprt, but Van Jacobson congestion control is
+ * integrated into the decision of whether a request is allowed to be
+ * woken up and given access to the transport.
+ */
+int xprt_reserve_xprt_cong(struct rpc_task *task)
+{
+       struct rpc_xprt *xprt = task->tk_xprt;
+       struct rpc_rqst *req = task->tk_rqstp;
+
+       if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
+               if (task == xprt->snd_task)
+                       return 1;
+               goto out_sleep;
+       }
+       if (__xprt_get_cong(xprt, task)) {
                xprt->snd_task = task;
                if (req) {
                        req->rq_bytes_sent = 0;
@@ -157,40 +262,63 @@ __xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
                }
                return 1;
        }
-       smp_mb__before_clear_bit();
-       clear_bit(XPRT_LOCKED, &xprt->sockstate);
-       smp_mb__after_clear_bit();
+       xprt_clear_locked(xprt);
 out_sleep:
-       dprintk("RPC: %4d failed to lock socket %p\n", task->tk_pid, xprt);
+       dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt);
        task->tk_timeout = 0;
        task->tk_status = -EAGAIN;
        if (req && req->rq_ntrans)
-               rpc_sleep_on(&xprt->resend, task, NULL, NULL);
+               rpc_sleep_on(&xprt->resend, task, NULL);
        else
-               rpc_sleep_on(&xprt->sending, task, NULL, NULL);
+               rpc_sleep_on(&xprt->sending, task, NULL);
        return 0;
 }
+EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong);
 
-static inline int
-xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
+static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
 {
        int retval;
 
-       spin_lock_bh(&xprt->sock_lock);
-       retval = __xprt_lock_write(xprt, task);
-       spin_unlock_bh(&xprt->sock_lock);
+       spin_lock_bh(&xprt->transport_lock);
+       retval = xprt->ops->reserve_xprt(task);
+       spin_unlock_bh(&xprt->transport_lock);
        return retval;
 }
 
+static void __xprt_lock_write_next(struct rpc_xprt *xprt)
+{
+       struct rpc_task *task;
+       struct rpc_rqst *req;
 
-static void
-__xprt_lock_write_next(struct rpc_xprt *xprt)
+       if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
+               return;
+
+       task = rpc_wake_up_next(&xprt->resend);
+       if (!task) {
+               task = rpc_wake_up_next(&xprt->sending);
+               if (!task)
+                       goto out_unlock;
+       }
+
+       req = task->tk_rqstp;
+       xprt->snd_task = task;
+       if (req) {
+               req->rq_bytes_sent = 0;
+               req->rq_ntrans++;
+       }
+       return;
+
+out_unlock:
+       xprt_clear_locked(xprt);
+}
+
+static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt)
 {
        struct rpc_task *task;
 
-       if (test_and_set_bit(XPRT_LOCKED, &xprt->sockstate))
+       if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
                return;
-       if (!xprt->nocong && RPCXPRT_CONGESTED(xprt))
+       if (RPCXPRT_CONGESTED(xprt))
                goto out_unlock;
        task = rpc_wake_up_next(&xprt->resend);
        if (!task) {
@@ -198,7 +326,7 @@ __xprt_lock_write_next(struct rpc_xprt *xprt)
                if (!task)
                        goto out_unlock;
        }
-       if (xprt->nocong || __xprt_get_cong(xprt, task)) {
+       if (__xprt_get_cong(xprt, task)) {
                struct rpc_rqst *req = task->tk_rqstp;
                xprt->snd_task = task;
                if (req) {
@@ -208,88 +336,47 @@ __xprt_lock_write_next(struct rpc_xprt *xprt)
                return;
        }
 out_unlock:
-       smp_mb__before_clear_bit();
-       clear_bit(XPRT_LOCKED, &xprt->sockstate);
-       smp_mb__after_clear_bit();
+       xprt_clear_locked(xprt);
 }
 
-/*
- * Releases the socket for use by other requests.
+/**
+ * xprt_release_xprt - allow other requests to use a transport
+ * @xprt: transport with other tasks potentially waiting
+ * @task: task that is releasing access to the transport
+ *
+ * Note that "task" can be NULL.  No congestion control is provided.
  */
-static void
-__xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
+void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
 {
        if (xprt->snd_task == task) {
-               xprt->snd_task = NULL;
-               smp_mb__before_clear_bit();
-               clear_bit(XPRT_LOCKED, &xprt->sockstate);
-               smp_mb__after_clear_bit();
+               xprt_clear_locked(xprt);
                __xprt_lock_write_next(xprt);
        }
 }
+EXPORT_SYMBOL_GPL(xprt_release_xprt);
 
-static inline void
-xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
-{
-       spin_lock_bh(&xprt->sock_lock);
-       __xprt_release_write(xprt, task);
-       spin_unlock_bh(&xprt->sock_lock);
-}
-
-/*
- * Write data to socket.
+/**
+ * xprt_release_xprt_cong - allow other requests to use a transport
+ * @xprt: transport with other tasks potentially waiting
+ * @task: task that is releasing access to the transport
+ *
+ * Note that "task" can be NULL.  Another task is awoken to use the
+ * transport if the transport's congestion window allows it.
  */
-static inline int
-xprt_sendmsg(struct rpc_xprt *xprt, struct rpc_rqst *req)
+void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task)
 {
-       struct socket   *sock = xprt->sock;
-       struct xdr_buf  *xdr = &req->rq_snd_buf;
-       struct sockaddr *addr = NULL;
-       int addrlen = 0;
-       unsigned int    skip;
-       int             result;
-
-       if (!sock)
-               return -ENOTCONN;
-
-       xprt_pktdump("packet data:",
-                               req->rq_svec->iov_base,
-                               req->rq_svec->iov_len);
-
-       /* For UDP, we need to provide an address */
-       if (!xprt->stream) {
-               addr = (struct sockaddr *) &xprt->addr;
-               addrlen = sizeof(xprt->addr);
+       if (xprt->snd_task == task) {
+               xprt_clear_locked(xprt);
+               __xprt_lock_write_next_cong(xprt);
        }
-       /* Dont repeat bytes */
-       skip = req->rq_bytes_sent;
-
-       clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
-       result = xdr_sendpages(sock, addr, addrlen, xdr, skip, MSG_DONTWAIT);
-
-       dprintk("RPC:      xprt_sendmsg(%d) = %d\n", xdr->len - skip, result);
-
-       if (result >= 0)
-               return result;
+}
+EXPORT_SYMBOL_GPL(xprt_release_xprt_cong);
 
-       switch (result) {
-       case -ECONNREFUSED:
-               /* When the server has died, an ICMP port unreachable message
-                * prompts ECONNREFUSED.
-                */
-       case -EAGAIN:
-               break;
-       case -ECONNRESET:
-       case -ENOTCONN:
-       case -EPIPE:
-               /* connection broken */
-               if (xprt->stream)
-                       result = -ENOTCONN;
-               break;
-       default:
-               printk(KERN_NOTICE "RPC: sendmsg returned error %d\n", -result);
-       }
-       return result;
+static inline void xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+       spin_lock_bh(&xprt->transport_lock);
+       xprt->ops->release_xprt(xprt, task);
+       spin_unlock_bh(&xprt->transport_lock);
 }
 
 /*
@@ -303,7 +390,7 @@ __xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task)
 
        if (req->rq_cong)
                return 1;
-       dprintk("RPC: %4d xprt_cwnd_limited cong = %ld cwnd = %ld\n",
+       dprintk("RPC: %5u xprt_cwnd_limited cong = %lu cwnd = %lu\n",
                        task->tk_pid, xprt->cong, xprt->cwnd);
        if (RPCXPRT_CONGESTED(xprt))
                return 0;
@@ -323,42 +410,142 @@ __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
                return;
        req->rq_cong = 0;
        xprt->cong -= RPC_CWNDSCALE;
-       __xprt_lock_write_next(xprt);
+       __xprt_lock_write_next_cong(xprt);
 }
 
-/*
- * Adjust RPC congestion window
+/**
+ * xprt_release_rqst_cong - housekeeping when request is complete
+ * @task: RPC request that recently completed
+ *
+ * Useful for transports that require congestion control.
+ */
+void xprt_release_rqst_cong(struct rpc_task *task)
+{
+       __xprt_put_cong(task->tk_xprt, task->tk_rqstp);
+}
+EXPORT_SYMBOL_GPL(xprt_release_rqst_cong);
+
+/**
+ * xprt_adjust_cwnd - adjust transport congestion window
+ * @task: recently completed RPC request used to adjust window
+ * @result: result code of completed RPC request
+ *
  * We use a time-smoothed congestion estimator to avoid heavy oscillation.
  */
-static void
-xprt_adjust_cwnd(struct rpc_xprt *xprt, int result)
+void xprt_adjust_cwnd(struct rpc_task *task, int result)
 {
-       unsigned long   cwnd;
+       struct rpc_rqst *req = task->tk_rqstp;
+       struct rpc_xprt *xprt = task->tk_xprt;
+       unsigned long cwnd = xprt->cwnd;
 
-       cwnd = xprt->cwnd;
        if (result >= 0 && cwnd <= xprt->cong) {
                /* The (cwnd >> 1) term makes sure
                 * the result gets rounded properly. */
                cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd;
                if (cwnd > RPC_MAXCWND(xprt))
                        cwnd = RPC_MAXCWND(xprt);
-               __xprt_lock_write_next(xprt);
+               __xprt_lock_write_next_cong(xprt);
        } else if (result == -ETIMEDOUT) {
                cwnd >>= 1;
                if (cwnd < RPC_CWNDSCALE)
                        cwnd = RPC_CWNDSCALE;
        }
-       dprintk("RPC:      cong %ld, cwnd was %ld, now %ld\n",
+       dprintk("RPC:       cong %ld, cwnd was %ld, now %ld\n",
                        xprt->cong, xprt->cwnd, cwnd);
        xprt->cwnd = cwnd;
+       __xprt_put_cong(xprt, req);
+}
+EXPORT_SYMBOL_GPL(xprt_adjust_cwnd);
+
+/**
+ * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue
+ * @xprt: transport with waiting tasks
+ * @status: result code to plant in each task before waking it
+ *
+ */
+void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status)
+{
+       if (status < 0)
+               rpc_wake_up_status(&xprt->pending, status);
+       else
+               rpc_wake_up(&xprt->pending);
+}
+EXPORT_SYMBOL_GPL(xprt_wake_pending_tasks);
+
+/**
+ * xprt_wait_for_buffer_space - wait for transport output buffer to clear
+ * @task: task to be put to sleep
+ * @action: function pointer to be executed after wait
+ */
+void xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action)
+{
+       struct rpc_rqst *req = task->tk_rqstp;
+       struct rpc_xprt *xprt = req->rq_xprt;
+
+       task->tk_timeout = req->rq_timeout;
+       rpc_sleep_on(&xprt->pending, task, action);
+}
+EXPORT_SYMBOL_GPL(xprt_wait_for_buffer_space);
+
+/**
+ * xprt_write_space - wake the task waiting for transport output buffer space
+ * @xprt: transport with waiting tasks
+ *
+ * Can be called in a soft IRQ context, so xprt_write_space never sleeps.
+ */
+void xprt_write_space(struct rpc_xprt *xprt)
+{
+       if (unlikely(xprt->shutdown))
+               return;
+
+       spin_lock_bh(&xprt->transport_lock);
+       if (xprt->snd_task) {
+               dprintk("RPC:       write space: waking waiting task on "
+                               "xprt %p\n", xprt);
+               rpc_wake_up_queued_task(&xprt->pending, xprt->snd_task);
+       }
+       spin_unlock_bh(&xprt->transport_lock);
+}
+EXPORT_SYMBOL_GPL(xprt_write_space);
+
+/**
+ * xprt_set_retrans_timeout_def - set a request's retransmit timeout
+ * @task: task whose timeout is to be set
+ *
+ * Set a request's retransmit timeout based on the transport's
+ * default timeout parameters.  Used by transports that don't adjust
+ * the retransmit timeout based on round-trip time estimation.
+ */
+void xprt_set_retrans_timeout_def(struct rpc_task *task)
+{
+       task->tk_timeout = task->tk_rqstp->rq_timeout;
 }
+EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_def);
 
 /*
- * Reset the major timeout value
+ * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout
+ * @task: task whose timeout is to be set
+ *
+ * Set a request's retransmit timeout using the RTT estimator.
  */
+void xprt_set_retrans_timeout_rtt(struct rpc_task *task)
+{
+       int timer = task->tk_msg.rpc_proc->p_timer;
+       struct rpc_clnt *clnt = task->tk_client;
+       struct rpc_rtt *rtt = clnt->cl_rtt;
+       struct rpc_rqst *req = task->tk_rqstp;
+       unsigned long max_timeout = clnt->cl_timeout->to_maxval;
+
+       task->tk_timeout = rpc_calc_rto(rtt, timer);
+       task->tk_timeout <<= rpc_ntimeo(rtt, timer) + req->rq_retries;
+       if (task->tk_timeout > max_timeout || task->tk_timeout == 0)
+               task->tk_timeout = max_timeout;
+}
+EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_rtt);
+
 static void xprt_reset_majortimeo(struct rpc_rqst *req)
 {
-       struct rpc_timeout *to = &req->rq_xprt->timeout;
+       const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout;
 
        req->rq_majortimeo = req->rq_timeout;
        if (to->to_exponential)
@@ -370,13 +557,15 @@ static void xprt_reset_majortimeo(struct rpc_rqst *req)
        req->rq_majortimeo += jiffies;
 }
 
-/*
- * Adjust timeout values etc for next retransmit
+/**
+ * xprt_adjust_timeout - adjust timeout values for next retransmit
+ * @req: RPC request containing parameters to use for the adjustment
+ *
  */
 int xprt_adjust_timeout(struct rpc_rqst *req)
 {
        struct rpc_xprt *xprt = req->rq_xprt;
-       struct rpc_timeout *to = &xprt->timeout;
+       const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout;
        int status = 0;
 
        if (time_before(jiffies, req->rq_majortimeo)) {
@@ -387,16 +576,14 @@ int xprt_adjust_timeout(struct rpc_rqst *req)
                if (to->to_maxval && req->rq_timeout >= to->to_maxval)
                        req->rq_timeout = to->to_maxval;
                req->rq_retries++;
-               pprintk("RPC: %lu retrans\n", jiffies);
        } else {
                req->rq_timeout = to->to_initval;
                req->rq_retries = 0;
                xprt_reset_majortimeo(req);
                /* Reset the RTT counters == "slow start" */
-               spin_lock_bh(&xprt->sock_lock);
+               spin_lock_bh(&xprt->transport_lock);
                rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval);
-               spin_unlock_bh(&xprt->sock_lock);
-               pprintk("RPC: %lu timeout\n", jiffies);
+               spin_unlock_bh(&xprt->transport_lock);
                status = -ETIMEDOUT;
        }
 
@@ -407,840 +594,305 @@ int xprt_adjust_timeout(struct rpc_rqst *req)
        return status;
 }
 
-/*
- * Close down a transport socket
- */
-static void
-xprt_close(struct rpc_xprt *xprt)
+static void xprt_autoclose(struct work_struct *work)
 {
-       struct socket   *sock = xprt->sock;
-       struct sock     *sk = xprt->inet;
-
-       if (!sk)
-               return;
-
-       write_lock_bh(&sk->sk_callback_lock);
-       xprt->inet = NULL;
-       xprt->sock = NULL;
-
-       sk->sk_user_data    = NULL;
-       sk->sk_data_ready   = xprt->old_data_ready;
-       sk->sk_state_change = xprt->old_state_change;
-       sk->sk_write_space  = xprt->old_write_space;
-       write_unlock_bh(&sk->sk_callback_lock);
-
-       sk->sk_no_check  = 0;
+       struct rpc_xprt *xprt =
+               container_of(work, struct rpc_xprt, task_cleanup);
 
-       sock_release(sock);
+       xprt->ops->close(xprt);
+       clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
+       xprt_release_write(xprt, NULL);
 }
 
-static void
-xprt_socket_autoclose(void *args)
+/**
+ * xprt_disconnect_done - mark a transport as disconnected
+ * @xprt: transport to flag for disconnect
+ *
+ */
+void xprt_disconnect_done(struct rpc_xprt *xprt)
 {
-       struct rpc_xprt *xprt = (struct rpc_xprt *)args;
-
-       xprt_disconnect(xprt);
-       xprt_close(xprt);
-       xprt_release_write(xprt, NULL);
+       dprintk("RPC:       disconnected transport %p\n", xprt);
+       spin_lock_bh(&xprt->transport_lock);
+       xprt_clear_connected(xprt);
+       xprt_wake_pending_tasks(xprt, -EAGAIN);
+       spin_unlock_bh(&xprt->transport_lock);
 }
+EXPORT_SYMBOL_GPL(xprt_disconnect_done);
 
-/*
- * Mark a transport as disconnected
+/**
+ * xprt_force_disconnect - force a transport to disconnect
+ * @xprt: transport to disconnect
+ *
  */
-static void
-xprt_disconnect(struct rpc_xprt *xprt)
+void xprt_force_disconnect(struct rpc_xprt *xprt)
 {
-       dprintk("RPC:      disconnected transport %p\n", xprt);
-       spin_lock_bh(&xprt->sock_lock);
-       xprt_clear_connected(xprt);
-       rpc_wake_up_status(&xprt->pending, -ENOTCONN);
-       spin_unlock_bh(&xprt->sock_lock);
+       /* Don't race with the test_bit() in xprt_clear_locked() */
+       spin_lock_bh(&xprt->transport_lock);
+       set_bit(XPRT_CLOSE_WAIT, &xprt->state);
+       /* Try to schedule an autoclose RPC call */
+       if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0)
+               queue_work(rpciod_workqueue, &xprt->task_cleanup);
+       xprt_wake_pending_tasks(xprt, -EAGAIN);
+       spin_unlock_bh(&xprt->transport_lock);
 }
 
-/*
- * Used to allow disconnection when we've been idle
+/**
+ * xprt_conditional_disconnect - force a transport to disconnect
+ * @xprt: transport to disconnect
+ * @cookie: 'connection cookie'
+ *
+ * This attempts to break the connection if and only if 'cookie' matches
+ * the current transport 'connection cookie'. It ensures that we don't
+ * try to break the connection more than once when we need to retransmit
+ * a batch of RPC requests.
+ *
  */
+void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie)
+{
+       /* Don't race with the test_bit() in xprt_clear_locked() */
+       spin_lock_bh(&xprt->transport_lock);
+       if (cookie != xprt->connect_cookie)
+               goto out;
+       if (test_bit(XPRT_CLOSING, &xprt->state) || !xprt_connected(xprt))
+               goto out;
+       set_bit(XPRT_CLOSE_WAIT, &xprt->state);
+       /* Try to schedule an autoclose RPC call */
+       if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0)
+               queue_work(rpciod_workqueue, &xprt->task_cleanup);
+       xprt_wake_pending_tasks(xprt, -EAGAIN);
+out:
+       spin_unlock_bh(&xprt->transport_lock);
+}
+
 static void
 xprt_init_autodisconnect(unsigned long data)
 {
        struct rpc_xprt *xprt = (struct rpc_xprt *)data;
 
-       spin_lock(&xprt->sock_lock);
+       spin_lock(&xprt->transport_lock);
        if (!list_empty(&xprt->recv) || xprt->shutdown)
                goto out_abort;
-       if (test_and_set_bit(XPRT_LOCKED, &xprt->sockstate))
+       if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
                goto out_abort;
-       spin_unlock(&xprt->sock_lock);
-       /* Let keventd close the socket */
-       if (test_bit(XPRT_CONNECTING, &xprt->sockstate) != 0)
-               xprt_release_write(xprt, NULL);
-       else
-               schedule_work(&xprt->task_cleanup);
+       spin_unlock(&xprt->transport_lock);
+       set_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
+       queue_work(rpciod_workqueue, &xprt->task_cleanup);
        return;
 out_abort:
-       spin_unlock(&xprt->sock_lock);
-}
-
-static void xprt_socket_connect(void *args)
-{
-       struct rpc_xprt *xprt = (struct rpc_xprt *)args;
-       struct socket *sock = xprt->sock;
-       int status = -EIO;
-
-       if (xprt->shutdown || xprt->addr.sin_port == 0)
-               goto out;
-
-       /*
-        * Start by resetting any existing state
-        */
-       xprt_close(xprt);
-       sock = xprt_create_socket(xprt, xprt->prot, xprt->resvport);
-       if (sock == NULL) {
-               /* couldn't create socket or bind to reserved port;
-                * this is likely a permanent error, so cause an abort */
-               goto out;
-       }
-       xprt_bind_socket(xprt, sock);
-       xprt_sock_setbufsize(xprt);
-
-       status = 0;
-       if (!xprt->stream)
-               goto out;
-
-       /*
-        * Tell the socket layer to start connecting...
-        */
-       status = sock->ops->connect(sock, (struct sockaddr *) &xprt->addr,
-                       sizeof(xprt->addr), O_NONBLOCK);
-       dprintk("RPC: %p  connect status %d connected %d sock state %d\n",
-                       xprt, -status, xprt_connected(xprt), sock->sk->sk_state);
-       if (status < 0) {
-               switch (status) {
-                       case -EINPROGRESS:
-                       case -EALREADY:
-                               goto out_clear;
-               }
-       }
-out:
-       if (status < 0)
-               rpc_wake_up_status(&xprt->pending, status);
-       else
-               rpc_wake_up(&xprt->pending);
-out_clear:
-       smp_mb__before_clear_bit();
-       clear_bit(XPRT_CONNECTING, &xprt->sockstate);
-       smp_mb__after_clear_bit();
+       spin_unlock(&xprt->transport_lock);
 }
 
-/*
- * Attempt to connect a TCP socket.
+/**
+ * xprt_connect - schedule a transport connect operation
+ * @task: RPC task that is requesting the connect
  *
  */
 void xprt_connect(struct rpc_task *task)
 {
        struct rpc_xprt *xprt = task->tk_xprt;
 
-       dprintk("RPC: %4d xprt_connect xprt %p %s connected\n", task->tk_pid,
+       dprintk("RPC: %5u xprt_connect xprt %p %s connected\n", task->tk_pid,
                        xprt, (xprt_connected(xprt) ? "is" : "is not"));
 
-       if (xprt->shutdown) {
-               task->tk_status = -EIO;
-               return;
-       }
-       if (!xprt->addr.sin_port) {
-               task->tk_status = -EIO;
+       if (!xprt_bound(xprt)) {
+               task->tk_status = -EAGAIN;
                return;
        }
        if (!xprt_lock_write(xprt, task))
                return;
        if (xprt_connected(xprt))
-               goto out_write;
-
-       if (task->tk_rqstp)
-               task->tk_rqstp->rq_bytes_sent = 0;
-
-       task->tk_timeout = RPC_CONNECT_TIMEOUT;
-       rpc_sleep_on(&xprt->pending, task, xprt_connect_status, NULL);
-       if (!test_and_set_bit(XPRT_CONNECTING, &xprt->sockstate)) {
-               /* Note: if we are here due to a dropped connection
-                *       we delay reconnecting by RPC_REESTABLISH_TIMEOUT/HZ
-                *       seconds
-                */
-               if (xprt->sock != NULL)
-                       schedule_delayed_work(&xprt->sock_connect,
-                                       RPC_REESTABLISH_TIMEOUT);
-               else {
-                       schedule_work(&xprt->sock_connect);
-                       if (!RPC_IS_ASYNC(task))
-                               flush_scheduled_work();
-               }
+               xprt_release_write(xprt, task);
+       else {
+               if (task->tk_rqstp)
+                       task->tk_rqstp->rq_bytes_sent = 0;
+
+               task->tk_timeout = xprt->connect_timeout;
+               rpc_sleep_on(&xprt->pending, task, xprt_connect_status);
+               xprt->stat.connect_start = jiffies;
+               xprt->ops->connect(task);
        }
        return;
- out_write:
-       xprt_release_write(xprt, task);
 }
 
-/*
- * We arrive here when awoken from waiting on connection establishment.
- */
-static void
-xprt_connect_status(struct rpc_task *task)
+static void xprt_connect_status(struct rpc_task *task)
 {
        struct rpc_xprt *xprt = task->tk_xprt;
 
-       if (task->tk_status >= 0) {
-               dprintk("RPC: %4d xprt_connect_status: connection established\n",
+       if (task->tk_status == 0) {
+               xprt->stat.connect_count++;
+               xprt->stat.connect_time += (long)jiffies - xprt->stat.connect_start;
+               dprintk("RPC: %5u xprt_connect_status: connection established\n",
                                task->tk_pid);
                return;
        }
 
-       /* if soft mounted, just cause this RPC to fail */
-       if (RPC_IS_SOFT(task))
-               task->tk_status = -EIO;
-
        switch (task->tk_status) {
-       case -ECONNREFUSED:
-       case -ECONNRESET:
-       case -ENOTCONN:
-               return;
+       case -EAGAIN:
+               dprintk("RPC: %5u xprt_connect_status: retrying\n", task->tk_pid);
+               break;
        case -ETIMEDOUT:
-               dprintk("RPC: %4d xprt_connect_status: timed out\n",
-                               task->tk_pid);
+               dprintk("RPC: %5u xprt_connect_status: connect attempt timed "
+                               "out\n", task->tk_pid);
                break;
        default:
-               printk(KERN_ERR "RPC: error %d connecting to server %s\n",
-                               -task->tk_status, task->tk_client->cl_server);
+               dprintk("RPC: %5u xprt_connect_status: error %d connecting to "
+                               "server %s\n", task->tk_pid, -task->tk_status,
+                               task->tk_client->cl_server);
+               xprt_release_write(xprt, task);
+               task->tk_status = -EIO;
        }
-       xprt_release_write(xprt, task);
 }
 
-/*
- * Look up the RPC request corresponding to a reply, and then lock it.
+/**
+ * xprt_lookup_rqst - find an RPC request corresponding to an XID
+ * @xprt: transport on which the original request was transmitted
+ * @xid: RPC XID of incoming reply
+ *
  */
-static inline struct rpc_rqst *
-xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid)
+struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid)
 {
        struct list_head *pos;
-       struct rpc_rqst *req = NULL;
 
        list_for_each(pos, &xprt->recv) {
                struct rpc_rqst *entry = list_entry(pos, struct rpc_rqst, rq_list);
-               if (entry->rq_xid == xid) {
-                       req = entry;
-                       break;
-               }
+               if (entry->rq_xid == xid)
+                       return entry;
        }
-       return req;
+
+       dprintk("RPC:       xprt_lookup_rqst did not find xid %08x\n",
+                       ntohl(xid));
+       xprt->stat.bad_xids++;
+       return NULL;
 }
+EXPORT_SYMBOL_GPL(xprt_lookup_rqst);
 
-/*
- * Complete reply received.
- * The TCP code relies on us to remove the request from xprt->pending.
+/**
+ * xprt_update_rtt - update an RPC client's RTT state after receiving a reply
+ * @task: RPC request that recently completed
+ *
  */
-static void
-xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied)
+void xprt_update_rtt(struct rpc_task *task)
 {
-       struct rpc_task *task = req->rq_task;
-       struct rpc_clnt *clnt = task->tk_client;
-
-       /* Adjust congestion window */
-       if (!xprt->nocong) {
-               unsigned timer = task->tk_msg.rpc_proc->p_timer;
-               xprt_adjust_cwnd(xprt, copied);
-               __xprt_put_cong(xprt, req);
-               if (timer) {
-                       if (req->rq_ntrans == 1)
-                               rpc_update_rtt(clnt->cl_rtt, timer,
-                                               (long)jiffies - req->rq_xtime);
-                       rpc_set_timeo(clnt->cl_rtt, timer, req->rq_ntrans - 1);
-               }
+       struct rpc_rqst *req = task->tk_rqstp;
+       struct rpc_rtt *rtt = task->tk_client->cl_rtt;
+       unsigned timer = task->tk_msg.rpc_proc->p_timer;
+
+       if (timer) {
+               if (req->rq_ntrans == 1)
+                       rpc_update_rtt(rtt, timer,
+                                       (long)jiffies - req->rq_xtime);
+               rpc_set_timeo(rtt, timer, req->rq_ntrans - 1);
        }
+}
+EXPORT_SYMBOL_GPL(xprt_update_rtt);
 
-#ifdef RPC_PROFILE
-       /* Profile only reads for now */
-       if (copied > 1024) {
-               static unsigned long    nextstat;
-               static unsigned long    pkt_rtt, pkt_len, pkt_cnt;
-
-               pkt_cnt++;
-               pkt_len += req->rq_slen + copied;
-               pkt_rtt += jiffies - req->rq_xtime;
-               if (time_before(nextstat, jiffies)) {
-                       printk("RPC: %lu %ld cwnd\n", jiffies, xprt->cwnd);
-                       printk("RPC: %ld %ld %ld %ld stat\n",
-                                       jiffies, pkt_cnt, pkt_len, pkt_rtt);
-                       pkt_rtt = pkt_len = pkt_cnt = 0;
-                       nextstat = jiffies + 5 * HZ;
-               }
-       }
-#endif
+/**
+ * xprt_complete_rqst - called when reply processing is complete
+ * @task: RPC request that recently completed
+ * @copied: actual number of bytes received from the transport
+ *
+ * Caller holds transport lock.
+ */
+void xprt_complete_rqst(struct rpc_task *task, int copied)
+{
+       struct rpc_rqst *req = task->tk_rqstp;
+       struct rpc_xprt *xprt = req->rq_xprt;
 
-       dprintk("RPC: %4d has input (%d bytes)\n", task->tk_pid, copied);
-       list_del_init(&req->rq_list);
-       req->rq_received = req->rq_private_buf.len = copied;
+       dprintk("RPC: %5u xid %08x complete (%d bytes received)\n",
+                       task->tk_pid, ntohl(req->rq_xid), copied);
 
-       /* ... and wake up the process. */
-       rpc_wake_up_task(task);
-       return;
+       xprt->stat.recvs++;
+       task->tk_rtt = (long)jiffies - req->rq_xtime;
+
+       list_del_init(&req->rq_list);
+       req->rq_private_buf.len = copied;
+       /* Ensure all writes are done before we update */
+       /* req->rq_reply_bytes_recvd */
+       smp_wmb();
+       req->rq_reply_bytes_recvd = copied;
+       rpc_wake_up_queued_task(&xprt->pending, task);
 }
+EXPORT_SYMBOL_GPL(xprt_complete_rqst);
 
-static size_t
-skb_read_bits(skb_reader_t *desc, void *to, size_t len)
+static void xprt_timer(struct rpc_task *task)
 {
-       if (len > desc->count)
-               len = desc->count;
-       if (skb_copy_bits(desc->skb, desc->offset, to, len))
-               return 0;
-       desc->count -= len;
-       desc->offset += len;
-       return len;
-}
-
-static size_t
-skb_read_and_csum_bits(skb_reader_t *desc, void *to, size_t len)
-{
-       unsigned int csum2, pos;
-
-       if (len > desc->count)
-               len = desc->count;
-       pos = desc->offset;
-       csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
-       desc->csum = csum_block_add(desc->csum, csum2, pos);
-       desc->count -= len;
-       desc->offset += len;
-       return len;
-}
-
-/*
- * We have set things up such that we perform the checksum of the UDP
- * packet in parallel with the copies into the RPC client iovec.  -DaveM
- */
-int
-csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
-{
-       skb_reader_t desc;
-
-       desc.skb = skb;
-       desc.offset = sizeof(struct udphdr);
-       desc.count = skb->len - desc.offset;
-
-       if (skb->ip_summed == CHECKSUM_UNNECESSARY)
-               goto no_checksum;
-
-       desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
-       if (xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_and_csum_bits) < 0)
-               return -1;
-       if (desc.offset != skb->len) {
-               unsigned int csum2;
-               csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
-               desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
-       }
-       if (desc.count)
-               return -1;
-       if ((unsigned short)csum_fold(desc.csum))
-               return -1;
-       return 0;
-no_checksum:
-       if (xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_bits) < 0)
-               return -1;
-       if (desc.count)
-               return -1;
-       return 0;
-}
-
-/*
- * Input handler for RPC replies. Called from a bottom half and hence
- * atomic.
- */
-static void
-udp_data_ready(struct sock *sk, int len)
-{
-       struct rpc_task *task;
-       struct rpc_xprt *xprt;
-       struct rpc_rqst *rovr;
-       struct sk_buff  *skb;
-       int err, repsize, copied;
-       u32 _xid, *xp;
-
-       read_lock(&sk->sk_callback_lock);
-       dprintk("RPC:      udp_data_ready...\n");
-       if (!(xprt = xprt_from_sock(sk))) {
-               printk("RPC:      udp_data_ready request not found!\n");
-               goto out;
-       }
-
-       dprintk("RPC:      udp_data_ready client %p\n", xprt);
-
-       if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
-               goto out;
-
-       if (xprt->shutdown)
-               goto dropit;
-
-       repsize = skb->len - sizeof(struct udphdr);
-       if (repsize < 4) {
-               printk("RPC: impossible RPC reply size %d!\n", repsize);
-               goto dropit;
-       }
-
-       /* Copy the XID from the skb... */
-       xp = skb_header_pointer(skb, sizeof(struct udphdr),
-                               sizeof(_xid), &_xid);
-       if (xp == NULL)
-               goto dropit;
-
-       /* Look up and lock the request corresponding to the given XID */
-       spin_lock(&xprt->sock_lock);
-       rovr = xprt_lookup_rqst(xprt, *xp);
-       if (!rovr)
-               goto out_unlock;
-       task = rovr->rq_task;
-
-       dprintk("RPC: %4d received reply\n", task->tk_pid);
-
-       if ((copied = rovr->rq_private_buf.buflen) > repsize)
-               copied = repsize;
-
-       /* Suck it into the iovec, verify checksum if not done by hw. */
-       if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb))
-               goto out_unlock;
-
-       /* Something worked... */
-       dst_confirm(skb->dst);
-
-       xprt_complete_rqst(xprt, rovr, copied);
-
- out_unlock:
-       spin_unlock(&xprt->sock_lock);
- dropit:
-       skb_free_datagram(sk, skb);
- out:
-       read_unlock(&sk->sk_callback_lock);
-}
-
-/*
- * Copy from an skb into memory and shrink the skb.
- */
-static inline size_t
-tcp_copy_data(skb_reader_t *desc, void *p, size_t len)
-{
-       if (len > desc->count)
-               len = desc->count;
-       if (skb_copy_bits(desc->skb, desc->offset, p, len)) {
-               dprintk("RPC:      failed to copy %zu bytes from skb. %zu bytes remain\n",
-                               len, desc->count);
-               return 0;
-       }
-       desc->offset += len;
-       desc->count -= len;
-       dprintk("RPC:      copied %zu bytes from skb. %zu bytes remain\n",
-                       len, desc->count);
-       return len;
-}
-
-/*
- * TCP read fragment marker
- */
-static inline void
-tcp_read_fraghdr(struct rpc_xprt *xprt, skb_reader_t *desc)
-{
-       size_t len, used;
-       char *p;
-
-       p = ((char *) &xprt->tcp_recm) + xprt->tcp_offset;
-       len = sizeof(xprt->tcp_recm) - xprt->tcp_offset;
-       used = tcp_copy_data(desc, p, len);
-       xprt->tcp_offset += used;
-       if (used != len)
-               return;
-       xprt->tcp_reclen = ntohl(xprt->tcp_recm);
-       if (xprt->tcp_reclen & 0x80000000)
-               xprt->tcp_flags |= XPRT_LAST_FRAG;
-       else
-               xprt->tcp_flags &= ~XPRT_LAST_FRAG;
-       xprt->tcp_reclen &= 0x7fffffff;
-       xprt->tcp_flags &= ~XPRT_COPY_RECM;
-       xprt->tcp_offset = 0;
-       /* Sanity check of the record length */
-       if (xprt->tcp_reclen < 4) {
-               printk(KERN_ERR "RPC: Invalid TCP record fragment length\n");
-               xprt_disconnect(xprt);
-       }
-       dprintk("RPC:      reading TCP record fragment of length %d\n",
-                       xprt->tcp_reclen);
-}
-
-static void
-tcp_check_recm(struct rpc_xprt *xprt)
-{
-       dprintk("RPC:      xprt = %p, tcp_copied = %lu, tcp_offset = %u, tcp_reclen = %u, tcp_flags = %lx\n",
-                       xprt, xprt->tcp_copied, xprt->tcp_offset, xprt->tcp_reclen, xprt->tcp_flags);
-       if (xprt->tcp_offset == xprt->tcp_reclen) {
-               xprt->tcp_flags |= XPRT_COPY_RECM;
-               xprt->tcp_offset = 0;
-               if (xprt->tcp_flags & XPRT_LAST_FRAG) {
-                       xprt->tcp_flags &= ~XPRT_COPY_DATA;
-                       xprt->tcp_flags |= XPRT_COPY_XID;
-                       xprt->tcp_copied = 0;
-               }
-       }
-}
-
-/*
- * TCP read xid
- */
-static inline void
-tcp_read_xid(struct rpc_xprt *xprt, skb_reader_t *desc)
-{
-       size_t len, used;
-       char *p;
-
-       len = sizeof(xprt->tcp_xid) - xprt->tcp_offset;
-       dprintk("RPC:      reading XID (%Zu bytes)\n", len);
-       p = ((char *) &xprt->tcp_xid) + xprt->tcp_offset;
-       used = tcp_copy_data(desc, p, len);
-       xprt->tcp_offset += used;
-       if (used != len)
-               return;
-       xprt->tcp_flags &= ~XPRT_COPY_XID;
-       xprt->tcp_flags |= XPRT_COPY_DATA;
-       xprt->tcp_copied = 4;
-       dprintk("RPC:      reading reply for XID %08x\n",
-                                               ntohl(xprt->tcp_xid));
-       tcp_check_recm(xprt);
-}
+       struct rpc_rqst *req = task->tk_rqstp;
+       struct rpc_xprt *xprt = req->rq_xprt;
 
-/*
- * TCP read and complete request
- */
-static inline void
-tcp_read_request(struct rpc_xprt *xprt, skb_reader_t *desc)
-{
-       struct rpc_rqst *req;
-       struct xdr_buf *rcvbuf;
-       size_t len;
-       ssize_t r;
-
-       /* Find and lock the request corresponding to this xid */
-       spin_lock(&xprt->sock_lock);
-       req = xprt_lookup_rqst(xprt, xprt->tcp_xid);
-       if (!req) {
-               xprt->tcp_flags &= ~XPRT_COPY_DATA;
-               dprintk("RPC:      XID %08x request not found!\n",
-                               ntohl(xprt->tcp_xid));
-               spin_unlock(&xprt->sock_lock);
+       if (task->tk_status != -ETIMEDOUT)
                return;
-       }
+       dprintk("RPC: %5u xprt_timer\n", task->tk_pid);
 
-       rcvbuf = &req->rq_private_buf;
-       len = desc->count;
-       if (len > xprt->tcp_reclen - xprt->tcp_offset) {
-               skb_reader_t my_desc;
-
-               len = xprt->tcp_reclen - xprt->tcp_offset;
-               memcpy(&my_desc, desc, sizeof(my_desc));
-               my_desc.count = len;
-               r = xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
-                                         &my_desc, tcp_copy_data);
-               desc->count -= r;
-               desc->offset += r;
+       spin_lock_bh(&xprt->transport_lock);
+       if (!req->rq_reply_bytes_recvd) {
+               if (xprt->ops->timer)
+                       xprt->ops->timer(task);
        } else
-               r = xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
-                                         desc, tcp_copy_data);
-
-       if (r > 0) {
-               xprt->tcp_copied += r;
-               xprt->tcp_offset += r;
-       }
-       if (r != len) {
-               /* Error when copying to the receive buffer,
-                * usually because we weren't able to allocate
-                * additional buffer pages. All we can do now
-                * is turn off XPRT_COPY_DATA, so the request
-                * will not receive any additional updates,
-                * and time out.
-                * Any remaining data from this record will
-                * be discarded.
-                */
-               xprt->tcp_flags &= ~XPRT_COPY_DATA;
-               dprintk("RPC:      XID %08x truncated request\n",
-                               ntohl(xprt->tcp_xid));
-               dprintk("RPC:      xprt = %p, tcp_copied = %lu, tcp_offset = %u, tcp_reclen = %u\n",
-                               xprt, xprt->tcp_copied, xprt->tcp_offset, xprt->tcp_reclen);
-               goto out;
-       }
-
-       dprintk("RPC:      XID %08x read %Zd bytes\n",
-                       ntohl(xprt->tcp_xid), r);
-       dprintk("RPC:      xprt = %p, tcp_copied = %lu, tcp_offset = %u, tcp_reclen = %u\n",
-                       xprt, xprt->tcp_copied, xprt->tcp_offset, xprt->tcp_reclen);
-
-       if (xprt->tcp_copied == req->rq_private_buf.buflen)
-               xprt->tcp_flags &= ~XPRT_COPY_DATA;
-       else if (xprt->tcp_offset == xprt->tcp_reclen) {
-               if (xprt->tcp_flags & XPRT_LAST_FRAG)
-                       xprt->tcp_flags &= ~XPRT_COPY_DATA;
-       }
-
-out:
-       if (!(xprt->tcp_flags & XPRT_COPY_DATA)) {
-               dprintk("RPC: %4d received reply complete\n",
-                               req->rq_task->tk_pid);
-               xprt_complete_rqst(xprt, req, xprt->tcp_copied);
-       }
-       spin_unlock(&xprt->sock_lock);
-       tcp_check_recm(xprt);
-}
-
-/*
- * TCP discard extra bytes from a short read
- */
-static inline void
-tcp_read_discard(struct rpc_xprt *xprt, skb_reader_t *desc)
-{
-       size_t len;
-
-       len = xprt->tcp_reclen - xprt->tcp_offset;
-       if (len > desc->count)
-               len = desc->count;
-       desc->count -= len;
-       desc->offset += len;
-       xprt->tcp_offset += len;
-       dprintk("RPC:      discarded %Zu bytes\n", len);
-       tcp_check_recm(xprt);
-}
-
-/*
- * TCP record receive routine
- * We first have to grab the record marker, then the XID, then the data.
- */
-static int
-tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
-               unsigned int offset, size_t len)
-{
-       struct rpc_xprt *xprt = rd_desc->arg.data;
-       skb_reader_t desc = {
-               .skb    = skb,
-               .offset = offset,
-               .count  = len,
-               .csum   = 0
-               };
-
-       dprintk("RPC:      tcp_data_recv\n");
-       do {
-               /* Read in a new fragment marker if necessary */
-               /* Can we ever really expect to get completely empty fragments? */
-               if (xprt->tcp_flags & XPRT_COPY_RECM) {
-                       tcp_read_fraghdr(xprt, &desc);
-                       continue;
-               }
-               /* Read in the xid if necessary */
-               if (xprt->tcp_flags & XPRT_COPY_XID) {
-                       tcp_read_xid(xprt, &desc);
-                       continue;
-               }
-               /* Read in the request data */
-               if (xprt->tcp_flags & XPRT_COPY_DATA) {
-                       tcp_read_request(xprt, &desc);
-                       continue;
-               }
-               /* Skip over any trailing bytes on short reads */
-               tcp_read_discard(xprt, &desc);
-       } while (desc.count);
-       dprintk("RPC:      tcp_data_recv done\n");
-       return len - desc.count;
+               task->tk_status = 0;
+       spin_unlock_bh(&xprt->transport_lock);
 }
 
-static void tcp_data_ready(struct sock *sk, int bytes)
+static inline int xprt_has_timer(struct rpc_xprt *xprt)
 {
-       struct rpc_xprt *xprt;
-       read_descriptor_t rd_desc;
-
-       read_lock(&sk->sk_callback_lock);
-       dprintk("RPC:      tcp_data_ready...\n");
-       if (!(xprt = xprt_from_sock(sk))) {
-               printk("RPC:      tcp_data_ready socket info not found!\n");
-               goto out;
-       }
-       if (xprt->shutdown)
-               goto out;
-
-       /* We use rd_desc to pass struct xprt to tcp_data_recv */
-       rd_desc.arg.data = xprt;
-       rd_desc.count = 65536;
-       tcp_read_sock(sk, &rd_desc, tcp_data_recv);
-out:
-       read_unlock(&sk->sk_callback_lock);
-}
-
-static void
-tcp_state_change(struct sock *sk)
-{
-       struct rpc_xprt *xprt;
-
-       read_lock(&sk->sk_callback_lock);
-       if (!(xprt = xprt_from_sock(sk)))
-               goto out;
-       dprintk("RPC:      tcp_state_change client %p...\n", xprt);
-       dprintk("RPC:      state %x conn %d dead %d zapped %d\n",
-                               sk->sk_state, xprt_connected(xprt),
-                               sock_flag(sk, SOCK_DEAD),
-                               sock_flag(sk, SOCK_ZAPPED));
-
-       switch (sk->sk_state) {
-       case TCP_ESTABLISHED:
-               spin_lock_bh(&xprt->sock_lock);
-               if (!xprt_test_and_set_connected(xprt)) {
-                       /* Reset TCP record info */
-                       xprt->tcp_offset = 0;
-                       xprt->tcp_reclen = 0;
-                       xprt->tcp_copied = 0;
-                       xprt->tcp_flags = XPRT_COPY_RECM | XPRT_COPY_XID;
-                       rpc_wake_up(&xprt->pending);
-               }
-               spin_unlock_bh(&xprt->sock_lock);
-               break;
-       case TCP_SYN_SENT:
-       case TCP_SYN_RECV:
-               break;
-       default:
-               xprt_disconnect(xprt);
-               break;
-       }
- out:
-       read_unlock(&sk->sk_callback_lock);
-}
-
-/*
- * Called when more output buffer space is available for this socket.
- * We try not to wake our writers until they can make "significant"
- * progress, otherwise we'll waste resources thrashing sock_sendmsg
- * with a bunch of small requests.
- */
-static void
-xprt_write_space(struct sock *sk)
-{
-       struct rpc_xprt *xprt;
-       struct socket   *sock;
-
-       read_lock(&sk->sk_callback_lock);
-       if (!(xprt = xprt_from_sock(sk)) || !(sock = sk->sk_socket))
-               goto out;
-       if (xprt->shutdown)
-               goto out;
-
-       /* Wait until we have enough socket memory */
-       if (xprt->stream) {
-               /* from net/core/stream.c:sk_stream_write_space */
-               if (sk_stream_wspace(sk) < sk_stream_min_wspace(sk))
-                       goto out;
-       } else {
-               /* from net/core/sock.c:sock_def_write_space */
-               if (!sock_writeable(sk))
-                       goto out;
-       }
-
-       if (!test_and_clear_bit(SOCK_NOSPACE, &sock->flags))
-               goto out;
-
-       spin_lock_bh(&xprt->sock_lock);
-       if (xprt->snd_task)
-               rpc_wake_up_task(xprt->snd_task);
-       spin_unlock_bh(&xprt->sock_lock);
-out:
-       read_unlock(&sk->sk_callback_lock);
-}
-
-/*
- * RPC receive timeout handler.
- */
-static void
-xprt_timer(struct rpc_task *task)
-{
-       struct rpc_rqst *req = task->tk_rqstp;
-       struct rpc_xprt *xprt = req->rq_xprt;
-
-       spin_lock(&xprt->sock_lock);
-       if (req->rq_received)
-               goto out;
-
-       xprt_adjust_cwnd(req->rq_xprt, -ETIMEDOUT);
-       __xprt_put_cong(xprt, req);
-
-       dprintk("RPC: %4d xprt_timer (%s request)\n",
-               task->tk_pid, req ? "pending" : "backlogged");
-
-       task->tk_status  = -ETIMEDOUT;
-out:
-       task->tk_timeout = 0;
-       rpc_wake_up_task(task);
-       spin_unlock(&xprt->sock_lock);
+       return xprt->idle_timeout != 0;
 }
 
-/*
- * Place the actual RPC call.
- * We have to copy the iovec because sendmsg fiddles with its contents.
+/**
+ * xprt_prepare_transmit - reserve the transport before sending a request
+ * @task: RPC task about to send a request
+ *
  */
-int
-xprt_prepare_transmit(struct rpc_task *task)
+int xprt_prepare_transmit(struct rpc_task *task)
 {
        struct rpc_rqst *req = task->tk_rqstp;
        struct rpc_xprt *xprt = req->rq_xprt;
        int err = 0;
 
-       dprintk("RPC: %4d xprt_prepare_transmit\n", task->tk_pid);
+       dprintk("RPC: %5u xprt_prepare_transmit\n", task->tk_pid);
 
-       if (xprt->shutdown)
-               return -EIO;
-
-       spin_lock_bh(&xprt->sock_lock);
-       if (req->rq_received && !req->rq_bytes_sent) {
-               err = req->rq_received;
+       spin_lock_bh(&xprt->transport_lock);
+       if (req->rq_reply_bytes_recvd && !req->rq_bytes_sent) {
+               err = req->rq_reply_bytes_recvd;
                goto out_unlock;
        }
-       if (!__xprt_lock_write(xprt, task)) {
+       if (!xprt->ops->reserve_xprt(task))
                err = -EAGAIN;
-               goto out_unlock;
-       }
-
-       if (!xprt_connected(xprt)) {
-               err = -ENOTCONN;
-               goto out_unlock;
-       }
 out_unlock:
-       spin_unlock_bh(&xprt->sock_lock);
+       spin_unlock_bh(&xprt->transport_lock);
        return err;
 }
 
-void
-xprt_transmit(struct rpc_task *task)
+void xprt_end_transmit(struct rpc_task *task)
+{
+       xprt_release_write(task->tk_rqstp->rq_xprt, task);
+}
+
+/**
+ * xprt_transmit - send an RPC request on a transport
+ * @task: controlling RPC task
+ *
+ * We have to copy the iovec because sendmsg fiddles with its contents.
+ */
+void xprt_transmit(struct rpc_task *task)
 {
-       struct rpc_clnt *clnt = task->tk_client;
        struct rpc_rqst *req = task->tk_rqstp;
        struct rpc_xprt *xprt = req->rq_xprt;
-       int status, retry = 0;
-
-
-       dprintk("RPC: %4d xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
-
-       /* set up everything as needed. */
-       /* Write the record marker */
-       if (xprt->stream) {
-               u32     *marker = req->rq_svec[0].iov_base;
+       int status;
 
-               *marker = htonl(0x80000000|(req->rq_slen-sizeof(*marker)));
-       }
+       dprintk("RPC: %5u xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
 
-       smp_rmb();
-       if (!req->rq_received) {
-               if (list_empty(&req->rq_list)) {
-                       spin_lock_bh(&xprt->sock_lock);
+       if (!req->rq_reply_bytes_recvd) {
+               if (list_empty(&req->rq_list) && rpc_reply_expected(task)) {
+                       /*
+                        * Add to the list only if we're expecting a reply
+                        */
+                       spin_lock_bh(&xprt->transport_lock);
                        /* Update the softirq receive buffer */
                        memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
                                        sizeof(req->rq_private_buf));
                        /* Add request to the receive list */
                        list_add_tail(&req->rq_list, &xprt->recv);
-                       spin_unlock_bh(&xprt->sock_lock);
+                       spin_unlock_bh(&xprt->transport_lock);
                        xprt_reset_majortimeo(req);
                        /* Turn off autodisconnect */
                        del_singleshot_timer_sync(&xprt->timer);
@@ -1248,103 +900,37 @@ xprt_transmit(struct rpc_task *task)
        } else if (!req->rq_bytes_sent)
                return;
 
-       /* Continue transmitting the packet/record. We must be careful
-        * to cope with writespace callbacks arriving _after_ we have
-        * called xprt_sendmsg().
-        */
-       while (1) {
-               req->rq_xtime = jiffies;
-               status = xprt_sendmsg(xprt, req);
-
-               if (status < 0)
-                       break;
-
-               if (xprt->stream) {
-                       req->rq_bytes_sent += status;
-
-                       /* If we've sent the entire packet, immediately
-                        * reset the count of bytes sent. */
-                       if (req->rq_bytes_sent >= req->rq_slen) {
-                               req->rq_bytes_sent = 0;
-                               goto out_receive;
-                       }
-               } else {
-                       if (status >= req->rq_slen)
-                               goto out_receive;
-                       status = -EAGAIN;
-                       break;
-               }
+       req->rq_connect_cookie = xprt->connect_cookie;
+       req->rq_xtime = jiffies;
+       status = xprt->ops->send_request(task);
+       if (status != 0) {
+               task->tk_status = status;
+               return;
+       }
 
-               dprintk("RPC: %4d xmit incomplete (%d left of %d)\n",
-                               task->tk_pid, req->rq_slen - req->rq_bytes_sent,
-                               req->rq_slen);
+       dprintk("RPC: %5u xmit complete\n", task->tk_pid);
+       spin_lock_bh(&xprt->transport_lock);
 
-               status = -EAGAIN;
-               if (retry++ > 50)
-                       break;
-       }
+       xprt->ops->set_retrans_timeout(task);
 
-       /* Note: at this point, task->tk_sleeping has not yet been set,
-        *       hence there is no danger of the waking up task being put on
-        *       schedq, and being picked up by a parallel run of rpciod().
-        */
-       task->tk_status = status;
+       xprt->stat.sends++;
+       xprt->stat.req_u += xprt->stat.sends - xprt->stat.recvs;
+       xprt->stat.bklog_u += xprt->backlog.qlen;
 
-       switch (status) {
-       case -EAGAIN:
-               if (test_bit(SOCK_ASYNC_NOSPACE, &xprt->sock->flags)) {
-                       /* Protect against races with xprt_write_space */
-                       spin_lock_bh(&xprt->sock_lock);
-                       /* Don't race with disconnect */
-                       if (!xprt_connected(xprt))
-                               task->tk_status = -ENOTCONN;
-                       else if (test_bit(SOCK_NOSPACE, &xprt->sock->flags)) {
-                               task->tk_timeout = req->rq_timeout;
-                               rpc_sleep_on(&xprt->pending, task, NULL, NULL);
-                       }
-                       spin_unlock_bh(&xprt->sock_lock);
-                       return;
-               }
-               /* Keep holding the socket if it is blocked */
-               rpc_delay(task, HZ>>4);
-               return;
-       case -ECONNREFUSED:
-               task->tk_timeout = RPC_REESTABLISH_TIMEOUT;
-               rpc_sleep_on(&xprt->sending, task, NULL, NULL);
-       case -ENOTCONN:
-               return;
-       default:
-               if (xprt->stream)
-                       xprt_disconnect(xprt);
-       }
-       xprt_release_write(xprt, task);
-       return;
- out_receive:
-       dprintk("RPC: %4d xmit complete\n", task->tk_pid);
-       /* Set the task's receive timeout value */
-       spin_lock_bh(&xprt->sock_lock);
-       if (!xprt->nocong) {
-               int timer = task->tk_msg.rpc_proc->p_timer;
-               task->tk_timeout = rpc_calc_rto(clnt->cl_rtt, timer);
-               task->tk_timeout <<= rpc_ntimeo(clnt->cl_rtt, timer) + req->rq_retries;
-               if (task->tk_timeout > xprt->timeout.to_maxval || task->tk_timeout == 0)
-                       task->tk_timeout = xprt->timeout.to_maxval;
-       } else
-               task->tk_timeout = req->rq_timeout;
        /* Don't race with disconnect */
        if (!xprt_connected(xprt))
                task->tk_status = -ENOTCONN;
-       else if (!req->rq_received)
-               rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer);
-       __xprt_release_write(xprt, task);
-       spin_unlock_bh(&xprt->sock_lock);
+       else if (!req->rq_reply_bytes_recvd && rpc_reply_expected(task)) {
+               /*
+                * Sleep on the pending queue since
+                * we're expecting a reply.
+                */
+               rpc_sleep_on(&xprt->pending, task, xprt_timer);
+       }
+       spin_unlock_bh(&xprt->transport_lock);
 }
 
-/*
- * Reserve an RPC call slot.
- */
-static inline void
-do_xprt_reserve(struct rpc_task *task)
+static inline void do_xprt_reserve(struct rpc_task *task)
 {
        struct rpc_xprt *xprt = task->tk_xprt;
 
@@ -1358,364 +944,216 @@ do_xprt_reserve(struct rpc_task *task)
                xprt_request_init(task, xprt);
                return;
        }
-       dprintk("RPC:      waiting for request slot\n");
+       dprintk("RPC:       waiting for request slot\n");
        task->tk_status = -EAGAIN;
        task->tk_timeout = 0;
-       rpc_sleep_on(&xprt->backlog, task, NULL, NULL);
+       rpc_sleep_on(&xprt->backlog, task, NULL);
 }
 
-void
-xprt_reserve(struct rpc_task *task)
+/**
+ * xprt_reserve - allocate an RPC request slot
+ * @task: RPC task requesting a slot allocation
+ *
+ * If no more slots are available, place the task on the transport's
+ * backlog queue.
+ */
+void xprt_reserve(struct rpc_task *task)
 {
        struct rpc_xprt *xprt = task->tk_xprt;
 
        task->tk_status = -EIO;
-       if (!xprt->shutdown) {
-               spin_lock(&xprt->xprt_lock);
-               do_xprt_reserve(task);
-               spin_unlock(&xprt->xprt_lock);
-       }
+       spin_lock(&xprt->reserve_lock);
+       do_xprt_reserve(task);
+       spin_unlock(&xprt->reserve_lock);
 }
 
-/*
- * Allocate a 'unique' XID
- */
-static inline u32 xprt_alloc_xid(struct rpc_xprt *xprt)
+static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt)
 {
        return xprt->xid++;
 }
 
 static inline void xprt_init_xid(struct rpc_xprt *xprt)
 {
-       get_random_bytes(&xprt->xid, sizeof(xprt->xid));
+       xprt->xid = net_random();
 }
 
-/*
- * Initialize RPC request
- */
-static void
-xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
+static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
 {
        struct rpc_rqst *req = task->tk_rqstp;
 
-       req->rq_timeout = xprt->timeout.to_initval;
+       req->rq_timeout = task->tk_client->cl_timeout->to_initval;
        req->rq_task    = task;
        req->rq_xprt    = xprt;
+       req->rq_buffer  = NULL;
        req->rq_xid     = xprt_alloc_xid(xprt);
-       dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid,
+       req->rq_release_snd_buf = NULL;
+       xprt_reset_majortimeo(req);
+       dprintk("RPC: %5u reserved req %p xid %08x\n", task->tk_pid,
                        req, ntohl(req->rq_xid));
 }
 
-/*
- * Release an RPC call slot
+/**
+ * xprt_release - release an RPC request slot
+ * @task: task which is finished with the slot
+ *
  */
-void
-xprt_release(struct rpc_task *task)
+void xprt_release(struct rpc_task *task)
 {
-       struct rpc_xprt *xprt = task->tk_xprt;
+       struct rpc_xprt *xprt;
        struct rpc_rqst *req;
+       int is_bc_request;
 
        if (!(req = task->tk_rqstp))
                return;
-       spin_lock_bh(&xprt->sock_lock);
-       __xprt_release_write(xprt, task);
-       __xprt_put_cong(xprt, req);
+
+       /* Preallocated backchannel request? */
+       is_bc_request = bc_prealloc(req);
+
+       xprt = req->rq_xprt;
+       rpc_count_iostats(task);
+       spin_lock_bh(&xprt->transport_lock);
+       xprt->ops->release_xprt(xprt, task);
+       if (xprt->ops->release_request)
+               xprt->ops->release_request(task);
        if (!list_empty(&req->rq_list))
                list_del(&req->rq_list);
        xprt->last_used = jiffies;
-       if (list_empty(&xprt->recv) && !xprt->shutdown)
-               mod_timer(&xprt->timer, xprt->last_used + XPRT_IDLE_TIMEOUT);
-       spin_unlock_bh(&xprt->sock_lock);
+       if (list_empty(&xprt->recv) && xprt_has_timer(xprt))
+               mod_timer(&xprt->timer,
+                               xprt->last_used + xprt->idle_timeout);
+       spin_unlock_bh(&xprt->transport_lock);
+       if (!bc_prealloc(req))
+               xprt->ops->buf_free(req->rq_buffer);
        task->tk_rqstp = NULL;
-       memset(req, 0, sizeof(*req));   /* mark unused */
+       if (req->rq_release_snd_buf)
+               req->rq_release_snd_buf(req);
 
-       dprintk("RPC: %4d release request %p\n", task->tk_pid, req);
+       /*
+        * Early exit if this is a backchannel preallocated request.
+        * There is no need to have it added to the RPC slot list.
+        */
+       if (is_bc_request)
+               return;
 
-       spin_lock(&xprt->xprt_lock);
-       list_add(&req->rq_list, &xprt->free);
-       xprt_clear_backlog(xprt);
-       spin_unlock(&xprt->xprt_lock);
-}
+       memset(req, 0, sizeof(*req));   /* mark unused */
 
-/*
- * Set default timeout parameters
- */
-static void
-xprt_default_timeout(struct rpc_timeout *to, int proto)
-{
-       if (proto == IPPROTO_UDP)
-               xprt_set_timeout(to, 5,  5 * HZ);
-       else
-               xprt_set_timeout(to, 5, 60 * HZ);
-}
+       dprintk("RPC: %5u release request %p\n", task->tk_pid, req);
 
-/*
- * Set constant timeout
- */
-void
-xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr)
-{
-       to->to_initval   = 
-       to->to_increment = incr;
-       to->to_maxval    = incr * retr;
-       to->to_retries   = retr;
-       to->to_exponential = 0;
+       spin_lock(&xprt->reserve_lock);
+       list_add(&req->rq_list, &xprt->free);
+       rpc_wake_up_next(&xprt->backlog);
+       spin_unlock(&xprt->reserve_lock);
 }
 
-unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
-unsigned int xprt_tcp_slot_table_entries = RPC_DEF_SLOT_TABLE;
-
-/*
- * Initialize an RPC client
+/**
+ * xprt_create_transport - create an RPC transport
+ * @args: rpc transport creation arguments
+ *
  */
-static struct rpc_xprt *
-xprt_setup(int proto, struct sockaddr_in *ap, struct rpc_timeout *to)
+struct rpc_xprt *xprt_create_transport(struct xprt_create *args)
 {
        struct rpc_xprt *xprt;
-       unsigned int entries;
-       size_t slot_table_size;
        struct rpc_rqst *req;
+       struct xprt_class *t;
 
-       dprintk("RPC:      setting up %s transport...\n",
-                               proto == IPPROTO_UDP? "UDP" : "TCP");
-
-       entries = (proto == IPPROTO_TCP)?
-               xprt_tcp_slot_table_entries : xprt_udp_slot_table_entries;
-
-       if ((xprt = kmalloc(sizeof(struct rpc_xprt), GFP_KERNEL)) == NULL)
-               return ERR_PTR(-ENOMEM);
-       memset(xprt, 0, sizeof(*xprt)); /* Nnnngh! */
-       xprt->max_reqs = entries;
-       slot_table_size = entries * sizeof(xprt->slot[0]);
-       xprt->slot = kmalloc(slot_table_size, GFP_KERNEL);
-       if (xprt->slot == NULL) {
-               kfree(xprt);
-               return ERR_PTR(-ENOMEM);
+       spin_lock(&xprt_list_lock);
+       list_for_each_entry(t, &xprt_list, list) {
+               if (t->ident == args->ident) {
+                       spin_unlock(&xprt_list_lock);
+                       goto found;
+               }
        }
-       memset(xprt->slot, 0, slot_table_size);
-
-       xprt->addr = *ap;
-       xprt->prot = proto;
-       xprt->stream = (proto == IPPROTO_TCP)? 1 : 0;
-       if (xprt->stream) {
-               xprt->cwnd = RPC_MAXCWND(xprt);
-               xprt->nocong = 1;
-               xprt->max_payload = (1U << 31) - 1;
-       } else {
-               xprt->cwnd = RPC_INITCWND;
-               xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
+       spin_unlock(&xprt_list_lock);
+       printk(KERN_ERR "RPC: transport (%d) not supported\n", args->ident);
+       return ERR_PTR(-EIO);
+
+found:
+       xprt = t->setup(args);
+       if (IS_ERR(xprt)) {
+               dprintk("RPC:       xprt_create_transport: failed, %ld\n",
+                               -PTR_ERR(xprt));
+               return xprt;
        }
-       spin_lock_init(&xprt->sock_lock);
-       spin_lock_init(&xprt->xprt_lock);
-       init_waitqueue_head(&xprt->cong_wait);
+
+       kref_init(&xprt->kref);
+       spin_lock_init(&xprt->transport_lock);
+       spin_lock_init(&xprt->reserve_lock);
 
        INIT_LIST_HEAD(&xprt->free);
        INIT_LIST_HEAD(&xprt->recv);
-       INIT_WORK(&xprt->sock_connect, xprt_socket_connect, xprt);
-       INIT_WORK(&xprt->task_cleanup, xprt_socket_autoclose, xprt);
-       init_timer(&xprt->timer);
-       xprt->timer.function = xprt_init_autodisconnect;
-       xprt->timer.data = (unsigned long) xprt;
+#if defined(CONFIG_NFS_V4_1)
+       spin_lock_init(&xprt->bc_pa_lock);
+       INIT_LIST_HEAD(&xprt->bc_pa_list);
+#endif /* CONFIG_NFS_V4_1 */
+
+       INIT_WORK(&xprt->task_cleanup, xprt_autoclose);
+       if (xprt_has_timer(xprt))
+               setup_timer(&xprt->timer, xprt_init_autodisconnect,
+                           (unsigned long)xprt);
+       else
+               init_timer(&xprt->timer);
        xprt->last_used = jiffies;
-       xprt->port = XPRT_MAX_RESVPORT;
-
-       /* Set timeout parameters */
-       if (to) {
-               xprt->timeout = *to;
-       } else
-               xprt_default_timeout(&xprt->timeout, xprt->prot);
+       xprt->cwnd = RPC_INITCWND;
+       xprt->bind_index = 0;
 
+       rpc_init_wait_queue(&xprt->binding, "xprt_binding");
        rpc_init_wait_queue(&xprt->pending, "xprt_pending");
        rpc_init_wait_queue(&xprt->sending, "xprt_sending");
        rpc_init_wait_queue(&xprt->resend, "xprt_resend");
        rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog");
 
        /* initialize free list */
-       for (req = &xprt->slot[entries-1]; req >= &xprt->slot[0]; req--)
+       for (req = &xprt->slot[xprt->max_reqs-1]; req >= &xprt->slot[0]; req--)
                list_add(&req->rq_list, &xprt->free);
 
        xprt_init_xid(xprt);
 
-       /* Check whether we want to use a reserved port */
-       xprt->resvport = capable(CAP_NET_BIND_SERVICE) ? 1 : 0;
-
-       dprintk("RPC:      created transport %p with %u slots\n", xprt,
+       dprintk("RPC:       created transport %p with %u slots\n", xprt,
                        xprt->max_reqs);
-       
        return xprt;
 }
 
-/*
- * Bind to a reserved port
- */
-static inline int xprt_bindresvport(struct rpc_xprt *xprt, struct socket *sock)
-{
-       struct sockaddr_in myaddr = {
-               .sin_family = AF_INET,
-       };
-       int             err, port;
-
-       /* Were we already bound to a given port? Try to reuse it */
-       port = xprt->port;
-       do {
-               myaddr.sin_port = htons(port);
-               err = sock->ops->bind(sock, (struct sockaddr *) &myaddr,
-                                               sizeof(myaddr));
-               if (err == 0) {
-                       xprt->port = port;
-                       return 0;
-               }
-               if (--port == 0)
-                       port = XPRT_MAX_RESVPORT;
-       } while (err == -EADDRINUSE && port != xprt->port);
-
-       printk("RPC: Can't bind to reserved port (%d).\n", -err);
-       return err;
-}
-
-static void
-xprt_bind_socket(struct rpc_xprt *xprt, struct socket *sock)
-{
-       struct sock     *sk = sock->sk;
-
-       if (xprt->inet)
-               return;
-
-       write_lock_bh(&sk->sk_callback_lock);
-       sk->sk_user_data = xprt;
-       xprt->old_data_ready = sk->sk_data_ready;
-       xprt->old_state_change = sk->sk_state_change;
-       xprt->old_write_space = sk->sk_write_space;
-       if (xprt->prot == IPPROTO_UDP) {
-               sk->sk_data_ready = udp_data_ready;
-               sk->sk_no_check = UDP_CSUM_NORCV;
-               xprt_set_connected(xprt);
-       } else {
-               tcp_sk(sk)->nonagle = 1;        /* disable Nagle's algorithm */
-               sk->sk_data_ready = tcp_data_ready;
-               sk->sk_state_change = tcp_state_change;
-               xprt_clear_connected(xprt);
-       }
-       sk->sk_write_space = xprt_write_space;
-
-       /* Reset to new socket */
-       xprt->sock = sock;
-       xprt->inet = sk;
-       write_unlock_bh(&sk->sk_callback_lock);
-
-       return;
-}
-
-/*
- * Set socket buffer length
- */
-void
-xprt_sock_setbufsize(struct rpc_xprt *xprt)
-{
-       struct sock *sk = xprt->inet;
-
-       if (xprt->stream)
-               return;
-       if (xprt->rcvsize) {
-               sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
-               sk->sk_rcvbuf = xprt->rcvsize * xprt->max_reqs *  2;
-       }
-       if (xprt->sndsize) {
-               sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
-               sk->sk_sndbuf = xprt->sndsize * xprt->max_reqs * 2;
-               sk->sk_write_space(sk);
-       }
-}
-
-/*
- * Datastream sockets are created here, but xprt_connect will create
- * and connect stream sockets.
- */
-static struct socket * xprt_create_socket(struct rpc_xprt *xprt, int proto, int resvport)
-{
-       struct socket   *sock;
-       int             type, err;
-
-       dprintk("RPC:      xprt_create_socket(%s %d)\n",
-                          (proto == IPPROTO_UDP)? "udp" : "tcp", proto);
-
-       type = (proto == IPPROTO_UDP)? SOCK_DGRAM : SOCK_STREAM;
-
-       if ((err = sock_create_kern(PF_INET, type, proto, &sock)) < 0) {
-               printk("RPC: can't create socket (%d).\n", -err);
-               return NULL;
-       }
-
-       /* If the caller has the capability, bind to a reserved port */
-       if (resvport && xprt_bindresvport(xprt, sock) < 0) {
-               printk("RPC: can't bind to reserved port.\n");
-               goto failed;
-       }
-
-       return sock;
-
-failed:
-       sock_release(sock);
-       return NULL;
-}
-
-/*
- * Create an RPC client transport given the protocol and peer address.
+/**
+ * xprt_destroy - destroy an RPC transport, killing off all requests.
+ * @kref: kref for the transport to destroy
+ *
  */
-struct rpc_xprt *
-xprt_create_proto(int proto, struct sockaddr_in *sap, struct rpc_timeout *to)
+static void xprt_destroy(struct kref *kref)
 {
-       struct rpc_xprt *xprt;
+       struct rpc_xprt *xprt = container_of(kref, struct rpc_xprt, kref);
 
-       xprt = xprt_setup(proto, sap, to);
-       if (IS_ERR(xprt))
-               dprintk("RPC:      xprt_create_proto failed\n");
-       else
-               dprintk("RPC:      xprt_create_proto created xprt %p\n", xprt);
-       return xprt;
-}
-
-/*
- * Prepare for transport shutdown.
- */
-static void
-xprt_shutdown(struct rpc_xprt *xprt)
-{
+       dprintk("RPC:       destroying transport %p\n", xprt);
        xprt->shutdown = 1;
-       rpc_wake_up(&xprt->sending);
-       rpc_wake_up(&xprt->resend);
-       rpc_wake_up(&xprt->pending);
-       rpc_wake_up(&xprt->backlog);
-       wake_up(&xprt->cong_wait);
        del_timer_sync(&xprt->timer);
 
-       /* synchronously wait for connect worker to finish */
-       cancel_delayed_work(&xprt->sock_connect);
-       flush_scheduled_work();
+       rpc_destroy_wait_queue(&xprt->binding);
+       rpc_destroy_wait_queue(&xprt->pending);
+       rpc_destroy_wait_queue(&xprt->sending);
+       rpc_destroy_wait_queue(&xprt->resend);
+       rpc_destroy_wait_queue(&xprt->backlog);
+       /*
+        * Tear down transport state and free the rpc_xprt
+        */
+       xprt->ops->destroy(xprt);
 }
 
-/*
- * Clear the xprt backlog queue
+/**
+ * xprt_put - release a reference to an RPC transport.
+ * @xprt: pointer to the transport
+ *
  */
-static int
-xprt_clear_backlog(struct rpc_xprt *xprt) {
-       rpc_wake_up_next(&xprt->backlog);
-       wake_up(&xprt->cong_wait);
-       return 1;
+void xprt_put(struct rpc_xprt *xprt)
+{
+       kref_put(&xprt->kref, xprt_destroy);
 }
 
-/*
- * Destroy an RPC transport, killing off all requests.
+/**
+ * xprt_get - return a reference to an RPC transport.
+ * @xprt: pointer to the transport
+ *
  */
-int
-xprt_destroy(struct rpc_xprt *xprt)
+struct rpc_xprt *xprt_get(struct rpc_xprt *xprt)
 {
-       dprintk("RPC:      destroying transport %p\n", xprt);
-       xprt_shutdown(xprt);
-       xprt_disconnect(xprt);
-       xprt_close(xprt);
-       kfree(xprt->slot);
-       kfree(xprt);
-
-       return 0;
+       kref_get(&xprt->kref);
+       return xprt;
 }