patch-2.1.32 linux/net/sunrpc/xprt.c

• Lines: 1368
• Date: Thu Mar 20 07:52:08 1997
• Orig file: v2.1.31/linux/net/sunrpc/xprt.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.31/linux/net/sunrpc/xprt.c linux/net/sunrpc/xprt.c
@@ -0,0 +1,1367 @@
+/*
+ *  linux/net/sunrpc/xprt.c
+ *
+ *  This is a generic RPC call interface supporting congestion avoidance,
+ *  and asynchronous calls.
+ *
+ *  The interface works like this:
+ *
+ *  -	When a process places a call, it allocates a request slot if
+ *	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.
+ *  -	When a packet arrives, the data_ready handler walks the list of
+ *	pending requests for that socket. 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
+ *	timeout values (minor timeout) or wakes up the caller with a status
+ *	of -ETIMEDOUT.
+ *  -	When the caller receives a notification from RPC that a reply arrived,
+ *	it should release the RPC slot, and process the reply.
+ *	If the call timed out, it may choose to retry the operation by
+ *	adjusting the initial timeout value, and simply calling rpc_call
+ *	again.
+ *
+ *  Support for async RPC is done through a set of RPC-specific scheduling
+ *  primitives that `transparently' work for processes as well as async
+ *  tasks that rely on callbacks.
+ *
+ *  Copyright (C) 1995, 1996, Olaf Kirch <okir@monad.swb.de>
+ */
+
+#define __KERNEL_SYSCALLS__
+
+#include <linux/version.h>
+#include <linux/types.h>
+#include <linux/malloc.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/net.h>
+#include <linux/mm.h>
+#include <linux/udp.h>
+#include <linux/unistd.h>
+#include <linux/sunrpc/clnt.h>
+#include <net/sock.h>
+
+#if LINUX_VERSION_CODE >= 0x020100
+#include <asm/uaccess.h>
+#endif
+
+#define SOCK_HAS_USER_DATA
+
+/*
+ * Local variables
+ */
+#ifndef SOCK_HAS_USER_DATA
+static struct rpc_xprt *	sock_list = NULL;
+#endif
+
+#ifdef RPC_DEBUG
+# undef  RPC_DEBUG_DATA
+# define RPCDBG_FACILITY	RPCDBG_XPRT
+#endif
+
+#ifndef MAX
+# define MAX(a, b)	((a) > (b)? (a) : (b))
+# define MIN(a, b)	((a) < (b)? (a) : (b))
+#endif
+
+/*
+ * Local functions
+ */
+static void	xprt_request_init(struct rpc_task *, struct rpc_xprt *);
+static void	xprt_transmit_status(struct rpc_task *task);
+static void	xprt_receive_status(struct rpc_task *task);
+static void	xprt_reserve_status(struct rpc_task *task);
+static void	xprt_reconn_timeout(struct rpc_task *task);
+static void	xprt_reconn_status(struct rpc_task *task);
+static struct socket *xprt_create_socket(int, struct sockaddr_in *,
+					struct rpc_timeout *);
+
+#ifdef RPC_DEBUG_DATA
+/*
+ * Print the buffer contents (first 128 bytes only--just enough for
+ * diropres return).
+ */
+static void
+xprt_pktdump(char *msg, u32 *packet, unsigned int count)
+{
+	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]);
+	}
+	dprintk("\n");
+}
+#else
+static inline void
+xprt_pktdump(char *msg, u32 *packet, unsigned int count)
+{
+	/* NOP */
+}
+#endif
+
+/*
+ * Look up RPC transport given an INET socket
+ */
+static inline struct rpc_xprt *
+xprt_from_sock(struct sock *sk)
+{
+#ifndef SOCK_HAS_USER_DATA
+	struct rpc_xprt		*xprt;
+
+	for (xprt = sock_list; xprt && sk != xprt->inet; xprt = xprt->link)
+		;
+	return xprt;
+#else
+	return (struct rpc_xprt *) sk->user_data;
+#endif
+}
+
+/*
+ * Write data to socket.
+ */
+static inline int
+xprt_sendmsg(struct rpc_xprt *xprt)
+{
+	struct socket	*sock = xprt->sock;
+	struct msghdr	msg;
+	unsigned long	oldfs;
+	int		result;
+
+	xprt_pktdump("packet data:",
+				xprt->snd_buf.io_vec->iov_base,
+				xprt->snd_buf.io_vec->iov_len);
+
+#if LINUX_VERSION_CODE >= 0x020100
+	msg.msg_flags   = MSG_DONTWAIT;
+	msg.msg_iov	= xprt->snd_buf.io_vec;
+	msg.msg_iovlen	= xprt->snd_buf.io_nr;
+	msg.msg_name	= (struct sockaddr *) &xprt->addr;
+	msg.msg_namelen = sizeof(xprt->addr);
+	msg.msg_control = NULL;
+
+	oldfs = get_fs(); set_fs(get_ds());
+	result = sock_sendmsg(sock, &msg, xprt->snd_buf.io_len);
+	set_fs(oldfs);
+#else
+	msg.msg_flags   = 0;
+	msg.msg_iov	= xprt->snd_buf.io_vec;
+	msg.msg_iovlen	= xprt->snd_buf.io_nr;
+	msg.msg_name	= (struct sockaddr *) &xprt->addr;
+	msg.msg_namelen = sizeof(xprt->addr);
+	msg.msg_control = NULL;
+
+	oldfs = get_fs(); set_fs(get_ds());
+	result = sock->ops->sendmsg(sock, &msg, xprt->snd_buf.io_len, 1, 0);
+	set_fs(oldfs);
+#endif
+
+	dprintk("RPC:      xprt_sendmsg(%d) = %d\n",
+				xprt->snd_buf.io_len, result);
+
+	if (result >= 0) {
+		xprt->snd_buf.io_len -= result;
+		return result;
+	}
+
+	switch (result) {
+	case -ECONNREFUSED:
+		/* When the server has died, an ICMP port unreachable message
+		 * prompts ECONNREFUSED.
+		 */
+		break;
+	case -ENOTCONN: case -EPIPE:
+		/* connection broken */
+		break;
+	default:
+		printk(KERN_NOTICE "RPC: sendmsg returned error %d\n", -result);
+		result = 0;
+	}
+	return result;
+}
+
+/*
+ * Read data from socket
+ */
+static inline int
+xprt_recvmsg(struct rpc_xprt *xprt, struct iovec *iov, int nr, int len)
+{
+	struct socket	*sock = xprt->sock;
+	struct sockaddr_in sin;
+	struct msghdr	msg;
+	unsigned long	oldfs;
+	int		result;
+
+#if LINUX_VERSION_CODE >= 0x020100
+	msg.msg_flags   = MSG_DONTWAIT;
+	msg.msg_iov	= iov;
+	msg.msg_iovlen	= nr;
+	msg.msg_name	= &sin;
+	msg.msg_namelen = sizeof(sin);
+	msg.msg_control = NULL;
+
+	oldfs = get_fs(); set_fs(get_ds());
+	result = sock_recvmsg(sock, &msg, len, MSG_DONTWAIT);
+	set_fs(oldfs);
+#else
+	int		alen = sizeof(sin);
+	msg.msg_flags   = 0;
+	msg.msg_iov	= iov;
+	msg.msg_iovlen	= nr;
+	msg.msg_name	= &sin;
+	msg.msg_namelen = sizeof(sin);
+	msg.msg_control = NULL;
+
+	oldfs = get_fs(); set_fs(get_ds());
+	result = sock->ops->recvmsg(sock, &msg, len, 1, 0, &alen);
+	set_fs(oldfs);
+#endif
+
+	if (!result && len)
+		result = -EAGAIN;
+
+	dprintk("RPC:      xprt_recvmsg(iov %p, len %d) = %d\n",
+						iov, len, result);
+	return result;
+}
+
+
+/*
+ * Adjust RPC congestion window
+ * We use a time-smoothed congestion estimator to avoid heavy oscillation.
+ */
+static void
+xprt_adjust_cwnd(struct rpc_xprt *xprt, int result)
+{
+	unsigned long	cwnd = xprt->cwnd;
+
+	if (xprt->nocong)
+		return;
+	if (result >= 0) {
+		if (xprt->cong < cwnd || jiffies < xprt->congtime)
+			return;
+		/* The (cwnd >> 1) term makes sure
+		 * the result gets rounded properly. */
+		cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd;
+		if (cwnd > RPC_MAXCWND)
+			cwnd = RPC_MAXCWND;
+		else
+			pprintk("RPC: %lu %ld cwnd\n", jiffies, cwnd);
+		xprt->congtime = jiffies + ((cwnd * HZ) << 2) / RPC_CWNDSCALE;
+		dprintk("RPC:      cong %08lx, cwnd was %08lx, now %08lx, "
+			"time %ld ms\n", xprt->cong, xprt->cwnd, cwnd,
+			(xprt->congtime-jiffies)*1000/HZ);
+	} else if (result == -ETIMEDOUT) {
+		if ((cwnd >>= 1) < RPC_CWNDSCALE)
+			cwnd = RPC_CWNDSCALE;
+		xprt->congtime = jiffies + ((cwnd * HZ) << 3) / RPC_CWNDSCALE;
+		dprintk("RPC:      cong %08lx, cwnd was %08lx, now %08lx, "
+			"time %ld ms\n", xprt->cong, xprt->cwnd, cwnd,
+			(xprt->congtime-jiffies)*1000/HZ);
+		pprintk("RPC: %lu %ld cwnd\n", jiffies, cwnd);
+	}
+
+	xprt->cwnd = cwnd;
+}
+
+/*
+ * Adjust timeout values etc for next retransmit
+ */
+int
+xprt_adjust_timeout(struct rpc_timeout *to)
+{
+	if (to->to_exponential)
+		to->to_current <<= 1;
+	else
+		to->to_current += to->to_increment;
+	if (to->to_maxval && to->to_current >= to->to_maxval) {
+		to->to_current = to->to_maxval;
+		to->to_retries = 0;
+	}
+	if (!to->to_current) {
+		printk(KERN_WARNING "xprt_adjust_timeout: to_current = 0!\n");
+		to->to_current = 5 * HZ;
+	}
+	pprintk("RPC: %lu %s\n", jiffies,
+			to->to_retries? "retrans" : "timeout");
+	return (to->to_retries)--;
+}
+
+/*
+ * Close down a transport socket
+ */
+static void
+xprt_close(struct rpc_xprt *xprt)
+{
+	struct sock	*sk = xprt->inet;
+
+#ifdef SOCK_HAS_USER_DATA
+	sk->user_data    = NULL;
+#endif
+	sk->data_ready   = xprt->old_data_ready;
+	sk->state_change = xprt->old_state_change;
+	sk->write_space  = xprt->old_write_space;
+
+	if (xprt->file)
+		close_fp(xprt->file);
+	else
+		sock_release(xprt->sock);
+}
+
+/*
+ * Mark a transport as disconnected
+ */
+static void
+xprt_disconnect(struct rpc_xprt *xprt)
+{
+	dprintk("RPC:      disconnected transport %p\n", xprt);
+	rpc_wake_up_status(&xprt->pending, -ENOTCONN);
+	rpc_wake_up_status(&xprt->sending, -ENOTCONN);
+	xprt->connected = 0;
+}
+
+/*
+ * Reconnect a broken TCP connection.
+ */
+void
+xprt_reconnect(struct rpc_task *task)
+{
+	struct rpc_xprt	*xprt = task->tk_xprt;
+	struct socket	*sock;
+	struct sock	*inet;
+	int		status;
+
+	dprintk("RPC: %4d xprt_reconnect %p connected %d\n",
+				task->tk_pid, xprt, xprt->connected);
+	task->tk_status = 0;
+
+	if (xprt->connecting) {
+		task->tk_timeout = xprt->timeout.to_maxval;
+		rpc_sleep_on(&xprt->reconn, task, NULL, NULL);
+		return;
+	}
+	xprt->connecting = 1;
+
+	/* Create an unconnected socket */
+	if (!(sock = xprt_create_socket(xprt->prot, NULL, &xprt->timeout)))
+		goto defer;
+
+#if LINUX_VERSION_CODE >= 0x020100
+	inet = sock->sk;
+#else
+	inet = (struct sock *) sock->data;
+#endif
+	inet->data_ready   = xprt->inet->data_ready;
+	inet->state_change = xprt->inet->state_change;
+	inet->write_space  = xprt->inet->write_space;
+#ifdef SOCK_HAS_USER_DATA
+	inet->user_data    = xprt;
+#endif
+
+	dprintk("RPC: %4d closing old socket\n", task->tk_pid);
+	xprt_disconnect(xprt);
+	xprt_close(xprt);
+
+	/* Reset to new socket and default congestion */
+	xprt->sock = sock;
+	xprt->inet = inet;
+	xprt->cwnd = RPC_INITCWND;
+
+	/* Now connect it asynchronously. */
+	dprintk("RPC: %4d connecting new socket\n", task->tk_pid);
+	status = sock->ops->connect(sock, (struct sockaddr *) &xprt->addr,
+				sizeof(xprt->addr), O_NONBLOCK);
+	if (status < 0) {
+		if (status != -EINPROGRESS && status != -EALREADY) {
+			printk("RPC: TCP connect error %d!\n", -status);
+			goto defer;
+		}
+
+		dprintk("RPC: %4d connect status %d connected %d\n",
+				task->tk_pid, status, xprt->connected);
+		task->tk_timeout = 60 * HZ;
+
+		disable_bh(NET_BH);
+		if (!xprt->connected) {
+			rpc_sleep_on(&xprt->reconn, task,
+				xprt_reconn_status, xprt_reconn_timeout);
+			enable_bh(NET_BH);
+			return;
+		}
+		enable_bh(NET_BH);
+	}
+
+	xprt->connecting = 0;
+	rpc_wake_up(&xprt->reconn);
+	return;
+
+defer:
+	task->tk_timeout = 30 * HZ;
+	rpc_sleep_on(&xprt->reconn, task, NULL, NULL);
+	xprt->connecting = 0;
+}
+
+/*
+ * Reconnect status
+ */
+static void
+xprt_reconn_status(struct rpc_task *task)
+{
+	struct rpc_xprt	*xprt = task->tk_xprt;
+
+	dprintk("RPC: %4d xprt_reconn_status %d\n",
+				task->tk_pid, task->tk_status);
+	if (!xprt->connected && task->tk_status != -ETIMEDOUT) {
+		task->tk_timeout = 30 * HZ;
+		rpc_sleep_on(&xprt->reconn, task, NULL, xprt_reconn_timeout);
+	}
+}
+
+/*
+ * Reconnect timeout. We just mark the transport as not being in the
+ * process of reconnecting, and leave the rest to the upper layers.
+ */
+static void
+xprt_reconn_timeout(struct rpc_task *task)
+{
+	dprintk("RPC: %4d xprt_reconn_timeout %d\n",
+				task->tk_pid, task->tk_status);
+	task->tk_status = -ENOTCONN;
+	task->tk_xprt->connecting = 0;
+	task->tk_timeout = 0;
+	rpc_wake_up_task(task);
+}
+
+/*
+ * Look up the RPC request corresponding to a reply.
+ */
+static inline struct rpc_rqst *
+xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid)
+{
+	struct rpc_task	*head, *task;
+	struct rpc_rqst	*req;
+	int		safe = 0;
+
+	if ((head = xprt->pending.task) != NULL) {
+		task = head;
+		do {
+			if ((req = task->tk_rqstp) && req->rq_xid == xid)
+				return req;
+			task = task->tk_next;
+			if (++safe > 100) {
+				printk("xprt_lookup_rqst: loop in Q!\n");
+				return NULL;
+			}
+		} while (task != head);
+	}
+	dprintk("RPC:      unknown XID %08x in reply.\n", xid);
+	return NULL;
+}
+
+/*
+ * Complete reply received.
+ * The TCP code relies on us to remove the request from xprt->pending.
+ */
+static inline void
+xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied)
+{
+	struct rpc_task	*task = req->rq_task;
+
+	req->rq_rlen   = copied;
+	req->rq_gotit  = 1;
+
+	/* Adjust congestion window */
+	xprt_adjust_cwnd(xprt, copied);
+
+#ifdef RPC_PROFILE
+	/* Profile only reads for now */
+	if (copied > 1024) {
+		static unsigned long	nextstat = 0;
+		static unsigned long	pkt_rtt = 0, pkt_len = 0, pkt_cnt = 0;
+
+		pkt_cnt++;
+		pkt_len += req->rq_slen + copied;
+		pkt_rtt += jiffies - req->rq_xtime;
+		if (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
+
+	/* ... and wake up the process. */
+	dprintk("RPC: %4d has input (%d bytes)\n", task->tk_pid, copied);
+	task->tk_status = copied;
+
+	rpc_wake_up_task(task);
+	return;
+}
+
+/*
+ * Input handler for RPC replies. Called from a bottom half and hence
+ * atomic.
+ */
+static inline 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;
+	struct iovec	iov[MAX_IOVEC];
+	unsigned long	oldfs;
+	int		err, repsize, copied;
+
+	dprintk("RPC:      udp_data_ready...\n");
+	if (!(xprt = xprt_from_sock(sk)))
+		return;
+	dprintk("RPC:      udp_data_ready client %p\n", xprt);
+
+	if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
+		return;
+	repsize = skb->len - 8;	/* don't account for UDP header */
+
+	if (repsize < 4) {
+		printk("RPC: impossible RPC reply size %d!\n", repsize);
+		goto dropit;
+	}
+
+	/* Look up the request corresponding to the given XID */
+	if (!(rovr = xprt_lookup_rqst(xprt, *(u32 *) (skb->h.raw + 8))))
+		goto dropit;
+	task = rovr->rq_task;
+
+	dprintk("RPC: %4d received reply\n", task->tk_pid);
+	xprt_pktdump("packet data:", (u32 *) (skb->h.raw+8), repsize);
+
+	if ((copied = rovr->rq_rlen) > repsize)
+		copied = repsize;
+
+	/* Okay, we have it. Copy datagram... */
+	memcpy(iov, rovr->rq_rvec, rovr->rq_rnr * sizeof(iov[0]));
+	oldfs = get_fs(); set_fs(get_ds());
+	skb_copy_datagram_iovec(skb, 8, iov, copied);
+	set_fs(oldfs);
+
+	xprt_complete_rqst(xprt, rovr, copied);
+
+dropit:
+	skb_free_datagram(sk, skb);
+	return;
+}
+
+/*
+ * TCP record receive routine
+ * This is not the most efficient code since we call recvfrom twice--
+ * first receiving the record marker and XID, then the data.
+ * 
+ * The optimal solution would be a RPC support in the TCP layer, which
+ * would gather all data up to the next record marker and then pass us
+ * the list of all TCP segments ready to be copied.
+ */
+static inline int
+tcp_input_record(struct rpc_xprt *xprt)
+{
+	struct rpc_rqst	*req;
+	struct iovec	*iov;
+	struct iovec	riov;
+	u32		offset;
+	int		result, maxcpy, reclen, avail, want;
+
+	dprintk("RPC:      tcp_input_record\n");
+	offset = xprt->tcp_offset;
+	result = -EAGAIN;
+	if (offset < 4 || (!xprt->tcp_more && offset < 8)) {
+		want = (xprt->tcp_more? 4 : 8) - offset;
+		dprintk("RPC:      reading header (%d bytes)\n", want);
+		riov.iov_base = xprt->tcp_recm.data + offset;
+		riov.iov_len  = want;
+		result = xprt_recvmsg(xprt, &riov, 1, want);
+		if (result < 0)
+			goto done;
+		offset += result;
+		if (result < want) {
+			result = -EAGAIN;
+			goto done;
+		}
+
+		/* Get the record length and mask out the more_fragments bit */
+		reclen = ntohl(xprt->tcp_reclen);
+		dprintk("RPC:      reclen %08x\n", reclen);
+		xprt->tcp_more = (reclen & 0x80000000)? 0 : 1;
+		if (!(reclen &= 0x7fffffff)) {
+			printk(KERN_NOTICE "RPC:      empty TCP record.\n");
+			return -ENOTCONN;	/* break connection */
+		}
+		xprt->tcp_total += reclen;
+		xprt->tcp_reclen = reclen;
+
+		dprintk("RPC:      got xid %08x reclen %d morefrags %d\n",
+			xprt->tcp_xid, xprt->tcp_reclen, xprt->tcp_more);
+		if (!xprt->tcp_copied
+		 && (req = xprt_lookup_rqst(xprt, xprt->tcp_xid))) {
+			iov = xprt->tcp_iovec;
+			memcpy(iov, req->rq_rvec, req->rq_rnr * sizeof(iov[0]));
+#if 0
+*(u32 *)iov->iov_base = req->rq_xid;
+#endif
+			iov->iov_base += 4;
+			iov->iov_len  -= 4;
+			xprt->tcp_copied = 4;
+			xprt->tcp_rqstp  = req;
+		}
+	} else {
+		reclen = xprt->tcp_reclen;
+	}
+
+	avail = reclen - (offset - 4);
+	if ((req = xprt->tcp_rqstp) && req->rq_xid == xprt->tcp_xid
+	 && req->rq_task->tk_rpcwait == &xprt->pending) {
+		want = MIN(req->rq_rlen - xprt->tcp_copied, avail);
+
+		dprintk("RPC: %4d TCP receiving %d bytes\n",
+					req->rq_task->tk_pid, want);
+		result = xprt_recvmsg(xprt, xprt->tcp_iovec, req->rq_rnr, want);
+		if (result < 0)
+			goto done;
+		xprt->tcp_copied += result;
+		offset += result;
+		avail  -= result;
+		if (result < want) {
+			result = -EAGAIN;
+			goto done;
+		}
+
+		maxcpy = MIN(req->rq_rlen, xprt->tcp_total);
+		if (xprt->tcp_copied == maxcpy && !xprt->tcp_more) {
+			dprintk("RPC: %4d received reply complete\n",
+					req->rq_task->tk_pid);
+			xprt_complete_rqst(xprt, req, xprt->tcp_total);
+			xprt->tcp_copied = 0;
+			xprt->tcp_rqstp  = NULL;
+		}
+		/* Request must be re-encoded before retransmit */
+		req->rq_damaged = 1;
+	}
+
+	/* Skip over any trailing bytes on short reads */
+	while (avail) {
+		static u8	dummy[64];
+
+		want = MIN(avail, sizeof(dummy));
+		riov.iov_base = dummy;
+		riov.iov_len  = want;
+		dprintk("RPC:      TCP skipping %d bytes\n", want);
+		result = xprt_recvmsg(xprt, &riov, 1, want);
+		if (result < 0)
+			goto done;
+		offset += result;
+		avail  -= result;
+		if (result < want) {
+			result = -EAGAIN;
+			goto done;
+		}
+	}
+	if (!xprt->tcp_more)
+		xprt->tcp_total = 0;
+	offset = 0;
+
+done:
+	dprintk("RPC:      tcp_input_record done (off %d total %d copied %d)\n",
+			offset, xprt->tcp_total, xprt->tcp_copied);
+	xprt->tcp_offset = offset;
+	return result;
+}
+
+/*
+ * data_ready callback for TCP.
+ */
+static void
+tcp_data_ready(struct sock *sk, int len)
+{
+	struct rpc_xprt	*xprt;
+	int		result, safe_retry = 0;
+
+	dprintk("RPC:      tcp_data_ready...\n");
+	if (!(xprt = xprt_from_sock(sk)))
+		return;
+	dprintk("RPC:      tcp_data_ready client %p\n", xprt);
+	dprintk("RPC:      state %x conn %d dead %d zapped %d\n",
+				sk->state, xprt->connected,
+				sk->dead, sk->zapped);
+
+	do {
+		if (safe_retry++ > 20)
+			return;
+		result = tcp_input_record(xprt);
+	} while (result >= 0);
+
+	switch (result) {
+	case -EAGAIN:
+		return;
+	case -ENOTCONN:
+	case -EPIPE:
+		xprt_disconnect(xprt);
+		return;
+	default:
+		printk("RPC: unexpected error %d from tcp_input_record\n",
+			result);
+	}
+}
+
+static void
+tcp_state_change(struct sock *sk)
+{
+	struct rpc_xprt	*xprt;
+
+	if (!(xprt = xprt_from_sock(sk)))
+		return;
+	dprintk("RPC:      tcp_state_change client %p...\n", xprt);
+	dprintk("RPC:      state %x conn %d dead %d zapped %d\n",
+				sk->state, xprt->connected,
+				sk->dead, sk->zapped);
+
+	if (sk->state == TCP_ESTABLISHED && !xprt->connected) {
+		xprt->connected = 1;
+		xprt->connecting = 0;
+		rpc_wake_up(&xprt->reconn);
+	} else if (sk->zapped) {
+		rpc_wake_up_status(&xprt->pending, -ENOTCONN);
+		rpc_wake_up_status(&xprt->sending, -ENOTCONN);
+		rpc_wake_up_status(&xprt->reconn,  -ENOTCONN);
+	}
+}
+
+static void
+tcp_write_space(struct sock *sk)
+{
+	struct rpc_xprt	*xprt;
+
+	if (!(xprt = xprt_from_sock(sk)))
+		return;
+	xprt->write_space = 1;
+	if (xprt->snd_task && !RPC_IS_RUNNING(xprt->snd_task))
+		rpc_wake_up_task(xprt->snd_task);
+}
+
+/*
+ * RPC receive timeout handler.
+ */
+static void
+xprt_timer(struct rpc_task *task)
+{
+	if (task->tk_rqstp)
+		xprt_adjust_cwnd(task->tk_xprt, -ETIMEDOUT);
+
+	dprintk("RPC: %4d xprt_timer (%s request)\n", task->tk_pid,
+			task->tk_rqstp? "pending" : "backlogged");
+
+	task->tk_status  = -ETIMEDOUT;
+	task->tk_timeout = 0;
+	rpc_wake_up_task(task);
+}
+
+/*
+ * (Partly) transmit the RPC packet
+ * Note that task->tk_status is either 0 or negative on return.
+ * Only when the reply is received will the status be set to a
+ * positive value.
+ */
+static inline int
+xprt_transmit_some(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+	struct rpc_rqst	*req = task->tk_rqstp;
+	int		result;
+
+	task->tk_status = 0;
+	if ((result = xprt_sendmsg(xprt)) >= 0) {
+		if (!xprt->snd_buf.io_len || !xprt->stream) {
+			rpc_wake_up_next(&xprt->sending);
+			return req->rq_slen;
+		}
+		result = -EAGAIN;
+	} else if (xprt->stream) {
+		if (result == -ENOTCONN || result == -EPIPE) {
+			xprt_disconnect(xprt);
+			result = -ENOTCONN;
+		}
+	}
+	return task->tk_status = result;
+}
+
+/*
+ * Place the actual RPC call.
+ * We have to copy the iovec because sendmsg fiddles with its contents.
+ */
+void
+xprt_transmit(struct rpc_task *task)
+{
+	struct rpc_timeout *timeo;
+	struct rpc_rqst	*req = task->tk_rqstp;
+	struct rpc_xprt	*xprt = req->rq_xprt;
+
+	dprintk("RPC: %4d xprt_transmit(%x)\n", task->tk_pid, 
+				*(u32 *)(req->rq_svec[0].iov_base));
+
+	if (xprt->shutdown) {
+		task->tk_status = -EIO;
+		return;
+	}
+
+	/* If we're not already in the process of transmitting our call,
+	 * set up everything as needed. */
+	if (xprt->snd_task != task) {
+		/* Write the record marker */
+		if (xprt->stream) {
+			u32	marker;
+
+			if (!xprt->connected) {
+				task->tk_status = -ENOTCONN;
+				return;
+			}
+			marker = htonl(0x80000000|(req->rq_slen-4));
+			*((u32 *) req->rq_svec[0].iov_base) = marker;
+		}
+
+		/* Reset timeout parameters */
+		timeo = &req->rq_timeout;
+		if (timeo->to_retries < 0) {
+			dprintk("RPC: %4d xprt_transmit reset timeo\n",
+						task->tk_pid);
+			timeo->to_retries = xprt->timeout.to_retries;
+			timeo->to_current = timeo->to_initval;
+		}
+
+#ifdef RPC_PROFILE
+		req->rq_xtime = jiffies;
+#endif
+		req->rq_gotit = 0;
+
+		if (xprt->snd_task) {
+			dprintk("RPC: %4d TCP write queue full (task %d)\n",
+					task->tk_pid, xprt->snd_task->tk_pid);
+			rpc_sleep_on(&xprt->sending, task,
+					xprt_transmit_status, NULL);
+			return;
+		}
+		xprt->snd_buf  = req->rq_snd_buf;
+		xprt->snd_task = task;
+	}
+
+	/* For fast networks/servers we have to put the request on
+	 * the pending list now:
+	 */
+	disable_bh(NET_BH);
+	rpc_add_wait_queue(&xprt->pending, task);
+	task->tk_callback = NULL;
+	enable_bh(NET_BH);
+
+	/* Continue transmitting the packet/record. We must be careful
+	 * to cope with writespace callbacks arriving _after_ we have
+	 * called xprt_sendmsg().
+	 */
+	while (1) {
+		xprt->write_space = 0;
+		if (xprt_transmit_some(xprt, task) != -EAGAIN) {
+			dprintk("RPC: %4d xmit complete\n", task->tk_pid);
+			xprt->snd_task = NULL;
+			return;
+		}
+
+		dprintk("RPC: %4d xmit incomplete (%d left of %d)\n",
+				task->tk_pid, xprt->snd_buf.io_len,
+				req->rq_slen);
+		task->tk_status = 0;
+		disable_bh(NET_BH);
+		if (!xprt->write_space) {
+			/* Remove from pending */
+			rpc_remove_wait_queue(task);
+			rpc_sleep_on(&xprt->sending, task,
+					xprt_transmit_status, NULL);
+			enable_bh(NET_BH);
+			return;
+		}
+		enable_bh(NET_BH);
+	}
+}
+
+/*
+ * This callback is invoked when the sending task is forced to sleep
+ * because the TCP write buffers are full
+ */
+static void
+xprt_transmit_status(struct rpc_task *task)
+{
+	struct rpc_xprt	*xprt = task->tk_client->cl_xprt;
+
+	dprintk("RPC: %4d transmit_status %d\n", task->tk_pid, task->tk_status);
+	if (xprt->snd_task == task) {
+		if (task->tk_status < 0)
+			xprt->snd_task = NULL;
+		xprt_disconnect(xprt);
+	}
+}
+
+/*
+ * Wait for the reply to our call.
+ * When the callback is invoked, the congestion window should have
+ * been updated already.
+ */
+void
+xprt_receive(struct rpc_task *task)
+{
+	struct rpc_rqst	*req = task->tk_rqstp;
+	struct rpc_xprt	*xprt = req->rq_xprt;
+
+	dprintk("RPC: %4d xprt_receive\n", task->tk_pid);
+	if (xprt->connected == 0) {
+		task->tk_status = -ENOTCONN;
+		return;
+	}
+
+	/*
+	 * Wait until rq_gotit goes non-null, or timeout elapsed.
+	 */
+	task->tk_timeout = req->rq_timeout.to_current;
+
+	disable_bh(NET_BH);
+	if (!req->rq_gotit) {
+		rpc_sleep_on(&xprt->pending, task,
+				xprt_receive_status, xprt_timer);
+	}
+	enable_bh(NET_BH);
+
+	dprintk("RPC: %4d xprt_receive returns %d\n",
+				task->tk_pid, task->tk_status);
+}
+
+static void
+xprt_receive_status(struct rpc_task *task)
+{
+	struct rpc_xprt	*xprt = task->tk_xprt;
+
+	if (xprt->stream && xprt->tcp_rqstp == task->tk_rqstp)
+		xprt->tcp_rqstp = NULL;
+}
+
+/*
+ * Reserve an RPC call slot.
+ */
+int
+xprt_reserve(struct rpc_task *task)
+{
+	struct rpc_xprt	*xprt = task->tk_xprt;
+
+	/* We already have an initialized request. */
+	if (task->tk_rqstp)
+		return 0;
+
+	dprintk("RPC: %4d xprt_reserve cong = %ld cwnd = %ld\n",
+				task->tk_pid, xprt->cong, xprt->cwnd);
+	if ((!RPCXPRT_CONGESTED(xprt) && xprt->free)) {
+		xprt_reserve_status(task);
+		task->tk_timeout = 0;
+	} else if (!task->tk_timeout) {
+		task->tk_status = -ENOBUFS;
+	} else {
+		dprintk("RPC:      xprt_reserve waiting on backlog\n");
+		rpc_sleep_on(&xprt->backlog, task, xprt_reserve_status, NULL);
+	}
+	dprintk("RPC: %4d xprt_reserve returns %d\n",
+				task->tk_pid, task->tk_status);
+	return task->tk_status;
+}
+
+/*
+ * Reservation callback
+ */
+static void
+xprt_reserve_status(struct rpc_task *task)
+{
+	struct rpc_xprt	*xprt = task->tk_xprt;
+	struct rpc_rqst	*req;
+
+	if (xprt->shutdown) {
+		task->tk_status = -EIO;
+	} else if (task->tk_status < 0) {
+		/* NOP */
+	} else if (task->tk_rqstp) {
+		/* We've already been given a request slot: NOP */
+	} else if (!RPCXPRT_CONGESTED(xprt)) {
+		/* OK: There's room for us. Grab a free slot and bump
+		 * congestion value */
+		if (!(req = xprt->free)) {
+			/* printk("RPC: inconsistent free list!\n"); */
+			rpc_debug = ~0;
+			dprintk("RPC: %4d inconsistent free list "
+					"(cong %ld cwnd %ld)\n",
+					task->tk_pid, xprt->cong, xprt->cwnd);
+			goto bummer;
+		}
+		if (req->rq_xid) {
+			printk("RPC: used rqst slot %p on free list!\n", req);
+			goto bummer;
+		}
+		xprt->free     = req->rq_next;
+		xprt->cong    += RPC_CWNDSCALE;
+		task->tk_rqstp = req;
+		req->rq_next   = NULL;
+		xprt_request_init(task, xprt);
+	} else {
+		task->tk_status = -EAGAIN;
+	}
+
+	if (xprt->free && !RPCXPRT_CONGESTED(xprt))
+		rpc_wake_up_next(&xprt->backlog);
+
+	return;
+
+bummer:
+	task->tk_status = -EIO;
+	xprt->free = NULL;
+	return;
+}
+
+/*
+ * Initialize RPC request
+ */
+static void
+xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
+{
+	struct rpc_rqst	*req = task->tk_rqstp;
+	static u32	xid = 0;
+
+	if (!xid)
+		xid = jiffies;
+
+	dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid, req, xid);
+	task->tk_status = 0;
+	req->rq_gotit	= 0;
+	req->rq_timeout = xprt->timeout;
+	req->rq_task	= task;
+	req->rq_xprt    = xprt;
+	req->rq_xid     = xid++;
+}
+
+/*
+ * Release an RPC call slot
+ */
+void
+xprt_release(struct rpc_task *task)
+{
+	struct rpc_xprt	*xprt = task->tk_xprt;
+	struct rpc_rqst	*req;
+
+	if (!(req = task->tk_rqstp))
+		return;
+	memset(req, 0, sizeof(*req));	/* mark unused */
+
+	dprintk("RPC: %4d release request %p\n", task->tk_pid, req);
+
+	/* remove slot from queue of pending */
+	disable_bh(NET_BH);
+	if (task->tk_rpcwait) {
+		printk("RPC: task of released request still queued!\n");
+#ifdef RPC_DEBUG
+		printk("RPC: (task is on %s)\n", rpc_qname(task->tk_rpcwait));
+#endif
+		rpc_del_timer(task);
+		rpc_remove_wait_queue(task);
+	}
+	enable_bh(NET_BH);
+
+	/* Decrease congestion value. If congestion threshold is not yet
+	 * reached, pass on the request slot.
+	 * This looks kind of kludgy, but it guarantees backlogged requests
+	 * are served in order.
+	 */
+	xprt->cong -= RPC_CWNDSCALE;
+	if (!RPCXPRT_CONGESTED(xprt)) {
+		struct rpc_task	*next = rpc_wake_up_next(&xprt->backlog);
+
+		if (next && next->tk_rqstp == 0) {
+			xprt->cong += RPC_CWNDSCALE;
+			next->tk_rqstp = req;
+			xprt_request_init(next, xprt);
+			return;
+		}
+	}
+
+	req->rq_next = xprt->free;
+	xprt->free   = req;
+}
+
+/*
+ * Set default timeout parameters
+ */
+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, 15 * HZ);
+}
+
+/*
+ * Set constant timeout
+ */
+void
+xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr)
+{
+	to->to_current   = 
+	to->to_initval   = 
+	to->to_increment = incr;
+	to->to_maxval    = incr * retr;
+	to->to_resrvval  = incr * retr;
+	to->to_retries   = retr;
+	to->to_exponential = 0;
+}
+
+/*
+ * Initialize an RPC client
+ */
+static struct rpc_xprt *
+xprt_setup(struct socket *sock, int proto,
+			struct sockaddr_in *ap, struct rpc_timeout *to)
+{
+	struct rpc_xprt	*xprt;
+	struct rpc_rqst	*req;
+	struct sock	*inet;
+	int		i;
+
+	dprintk("RPC:      setting up %s transport...\n",
+				proto == IPPROTO_UDP? "UDP" : "TCP");
+
+#if LINUX_VERSION_CODE >= 0x020100
+	inet = sock->sk;
+#else
+	inet = (struct sock *) sock->data;
+#endif
+
+	if ((xprt = kmalloc(sizeof(struct rpc_xprt), GFP_KERNEL)) == NULL)
+		return NULL;
+	memset(xprt, 0, sizeof(*xprt)); /* Nnnngh! */
+
+	xprt->file = NULL;
+	xprt->sock = sock;
+	xprt->inet = inet;
+	xprt->addr = *ap;
+	xprt->prot = proto;
+	xprt->stream = (proto == IPPROTO_TCP)? 1 : 0;
+	xprt->cwnd = RPC_INITCWND;
+#ifdef SOCK_HAS_USER_DATA
+	inet->user_data = xprt;
+#else
+	xprt->link = sock_list;
+	sock_list = xprt;
+#endif
+	xprt->old_data_ready = inet->data_ready;
+	xprt->old_state_change = inet->state_change;
+	xprt->old_write_space = inet->write_space;
+	if (proto == IPPROTO_UDP) {
+		inet->data_ready = udp_data_ready;
+	} else {
+		inet->data_ready = tcp_data_ready;
+		inet->state_change = tcp_state_change;
+		inet->write_space = tcp_write_space;
+		xprt->nocong = 1;
+	}
+	xprt->connected = 1;
+
+	/* Set timeout parameters */
+	if (to) {
+		xprt->timeout = *to;
+		xprt->timeout.to_current = to->to_initval;
+		xprt->timeout.to_resrvval = to->to_maxval << 1;
+	} else {
+		xprt_default_timeout(&xprt->timeout, xprt->prot);
+	}
+
+	xprt->pending = RPC_INIT_WAITQ("xprt_pending");
+	xprt->sending = RPC_INIT_WAITQ("xprt_sending");
+	xprt->backlog = RPC_INIT_WAITQ("xprt_backlog");
+	xprt->reconn  = RPC_INIT_WAITQ("xprt_reconn");
+
+	/* initialize free list */
+	for (i = 0, req = xprt->slot; i < RPC_MAXREQS-1; i++, req++)
+		req->rq_next = req + 1;
+	req->rq_next = NULL;
+	xprt->free = xprt->slot;
+
+	dprintk("RPC:      created transport %p\n", xprt);
+	return xprt;
+}
+
+/*
+ * Create and initialize an RPC client given an open file.
+ * This is obsolete now.
+ */
+#if 0
+struct rpc_xprt *
+xprt_create(struct file *file, struct sockaddr_in *ap, struct rpc_timeout *to)
+{
+	struct rpc_xprt	*xprt;
+	struct socket	*sock;
+	int		proto;
+
+	if (!file) {
+		printk("RPC: file == NULL in xprt_create!\n");
+		return NULL;
+	}
+
+	sock = &file->f_inode->u.socket_i;
+	if (sock->ops->family != AF_INET) {
+		printk(KERN_WARNING "RPC: only INET sockets supported\n");
+		return NULL;
+	}
+
+	proto = (sock->type == SOCK_DGRAM)? IPPROTO_UDP : IPPROTO_TCP;
+	if ((xprt = xprt_setup(sock, proto, ap, to)) != NULL) {
+		xprt->file = file;
+		file->f_count++;
+	}
+
+	return xprt;
+}
+#endif
+
+/*
+ * Bind to a reserved port
+ */
+static inline int
+xprt_bindresvport(struct socket *sock)
+{
+	struct sockaddr_in myaddr;
+	int		err, port;
+
+	memset(&myaddr, 0, sizeof(myaddr));
+	myaddr.sin_family = AF_INET;
+	port = 800;
+	do {
+		myaddr.sin_port = htons(port);
+		err = sock->ops->bind(sock, (struct sockaddr *) &myaddr,
+						sizeof(myaddr));
+	} while (err == -EADDRINUSE && --port > 0);
+
+	if (err < 0)
+		printk("RPC: Can't bind to reserved port (%d).\n", -err);
+
+	return err;
+}
+
+/*
+ * Create a client socket given the protocol and peer address.
+ */
+static struct socket *
+xprt_create_socket(int proto, struct sockaddr_in *sap, struct rpc_timeout *to)
+{
+	struct socket	*sock;
+	int		type, err;
+
+	dprintk("RPC:      xprt_create_socket(%08lx, %s %d)\n",
+			   sap? ntohl(sap->sin_addr.s_addr) : 0,
+			   (proto == IPPROTO_UDP)? "udp" : "tcp", proto);
+
+	type = (proto == IPPROTO_UDP)? SOCK_DGRAM : SOCK_STREAM;
+	if ((err = sock_create(AF_INET, type, proto, &sock)) < 0) {
+		printk("RPC: can't create socket (%d).\n", -err);
+		goto failed;
+	}
+
+	/* If the caller has root privs, bind to a reserved port */
+	if (!current->fsuid && xprt_bindresvport(sock) < 0)
+		goto failed;
+
+	if (type == SOCK_STREAM && sap) {
+		err = sock->ops->connect(sock, (struct sockaddr *) sap,
+						sizeof(*sap), 0);
+		if (err < 0) {
+			printk("RPC: TCP connect failed (%d).\n", -err);
+			goto failed;
+		}
+	}
+
+	return sock;
+
+failed:
+	sock_release(sock);
+	return NULL;
+}
+
+/*
+ * Create an RPC client transport given the protocol and peer address.
+ */
+struct rpc_xprt *
+xprt_create_proto(int proto, struct sockaddr_in *sap, struct rpc_timeout *to)
+{
+	struct socket	*sock;
+	struct rpc_xprt	*xprt;
+
+	dprintk("RPC:      xprt_create_proto called\n");
+
+	if (!(sock = xprt_create_socket(proto, sap, to)))
+		return NULL;
+
+	if (!(xprt = xprt_setup(sock, proto, sap, to)))
+		sock_release(sock);
+
+	return xprt;
+}
+
+/*
+ * Prepare for transport shutdown.
+ */
+void
+xprt_shutdown(struct rpc_xprt *xprt)
+{
+	xprt->shutdown = 1;
+	rpc_wake_up(&xprt->sending);
+	rpc_wake_up(&xprt->pending);
+	rpc_wake_up(&xprt->backlog);
+	rpc_wake_up(&xprt->reconn);
+}
+
+/*
+ * Destroy an RPC transport, killing off all requests.
+ */
+int
+xprt_destroy(struct rpc_xprt *xprt)
+{
+#ifndef SOCK_HAS_USER_DATA
+	struct rpc_xprt	**q;
+
+	for (q = &sock_list; *q && *q != xprt; q = &((*q)->link))
+		;
+	if (!*q) {
+		printk(KERN_WARNING "xprt_destroy: unknown socket!\n");
+		return -EIO;	/* why is there no EBUGGYSOFTWARE */
+	}
+	*q = xprt->link;
+#endif
+
+	dprintk("RPC:      destroying transport %p\n", xprt);
+	xprt_close(xprt);
+	kfree(xprt);
+
+	return 0;
+}