net/9p/trans_fd.c - kernel/msm - Gitiles

 /*
  * linux/fs/9p/trans_fd.c
  *
  * Fd transport layer.  Includes deprecated socket layer.
  *
  *  Copyright (C) 2006 by Russ Cox <rsc@swtch.com>
  *  Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net>
  *  Copyright (C) 2004-2007 by Eric Van Hensbergen <ericvh@gmail.com>
  *  Copyright (C) 1997-2002 by Ron Minnich <rminnich@sarnoff.com>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License version 2
  *  as published by the Free Software Foundation.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to:
  *  Free Software Foundation
  *  51 Franklin Street, Fifth Floor
  *  Boston, MA  02111-1301  USA
  *
  */

 #include <linux/in.h>
 #include <linux/module.h>
 #include <linux/net.h>
 #include <linux/ipv6.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/un.h>
 #include <linux/uaccess.h>
 #include <linux/inet.h>
 #include <linux/idr.h>
 #include <linux/file.h>
 #include <linux/parser.h>
 #include <net/9p/9p.h>
 #include <net/9p/transport.h>

 #define P9_PORT 564
 #define MAX_SOCK_BUF (64*1024)


 struct p9_fd_opts {
 	int rfd;
 	int wfd;
 	u16 port;
 };

 struct p9_trans_fd {
 	struct file *rd;
 	struct file *wr;
 };

 /*
   * Option Parsing (code inspired by NFS code)
   *  - a little lazy - parse all fd-transport options
   */

 enum {
 	/* Options that take integer arguments */
 	Opt_port, Opt_rfdno, Opt_wfdno, Opt_err,
 };

 static match_table_t tokens = {
 	{Opt_port, "port=%u"},
 	{Opt_rfdno, "rfdno=%u"},
 	{Opt_wfdno, "wfdno=%u"},
 	{Opt_err, NULL},
 };

 /**
  * v9fs_parse_options - parse mount options into session structure
  * @options: options string passed from mount
  * @v9ses: existing v9fs session information
  *
  */

 static void parse_opts(char *options, struct p9_fd_opts *opts)
 {
 	char *p;
 	substring_t args[MAX_OPT_ARGS];
 	int option;
 	int ret;

 	opts->port = P9_PORT;
 	opts->rfd = ~0;
 	opts->wfd = ~0;

 	if (!options)
 		return;

 	while ((p = strsep(&options, ",")) != NULL) {
 		int token;
 		if (!*p)
 			continue;
 		token = match_token(p, tokens, args);
 		ret = match_int(&args[0], &option);
 		if (ret < 0) {
 			P9_DPRINTK(P9_DEBUG_ERROR,
 			 "integer field, but no integer?\n");
 			continue;
 		}
 		switch (token) {
 		case Opt_port:
 			opts->port = option;
 			break;
 		case Opt_rfdno:
 			opts->rfd = option;
 			break;
 		case Opt_wfdno:
 			opts->wfd = option;
 			break;
 		default:
 			continue;
 		}
 	}
 }

 static int p9_fd_open(struct p9_trans *trans, int rfd, int wfd)
 {
 	struct p9_trans_fd *ts = kmalloc(sizeof(struct p9_trans_fd),
 					   GFP_KERNEL);
 	if (!ts)
 		return -ENOMEM;

 	ts->rd = fget(rfd);
 	ts->wr = fget(wfd);
 	if (!ts->rd || !ts->wr) {
 		if (ts->rd)
 			fput(ts->rd);
 		if (ts->wr)
 			fput(ts->wr);
 		kfree(ts);
 		return -EIO;
 	}

 	trans->priv = ts;
 	trans->status = Connected;

 	return 0;
 }

 static int p9_socket_open(struct p9_trans *trans, struct socket *csocket)
 {
 	int fd, ret;

 	csocket->sk->sk_allocation = GFP_NOIO;
 	fd = sock_map_fd(csocket);
 	if (fd < 0) {
 		P9_EPRINTK(KERN_ERR, "p9_socket_open: failed to map fd\n");
 		return fd;
 	}

 	ret = p9_fd_open(trans, fd, fd);
 	if (ret < 0) {
 		P9_EPRINTK(KERN_ERR, "p9_socket_open: failed to open fd\n");
 		sockfd_put(csocket);
 		return ret;
 	}

 	((struct p9_trans_fd *)trans->priv)->rd->f_flags |= O_NONBLOCK;

 	return 0;
 }

 /**
  * p9_fd_read- read from a fd
  * @v9ses: session information
  * @v: buffer to receive data into
  * @len: size of receive buffer
  *
  */
 static int p9_fd_read(struct p9_trans *trans, void *v, int len)
 {
 	int ret;
 	struct p9_trans_fd *ts = NULL;

 	if (trans && trans->status != Disconnected)
 		ts = trans->priv;

 	if (!ts)
 		return -EREMOTEIO;

 	if (!(ts->rd->f_flags & O_NONBLOCK))
 		P9_DPRINTK(P9_DEBUG_ERROR, "blocking read ...\n");

 	ret = kernel_read(ts->rd, ts->rd->f_pos, v, len);
 	if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
 		trans->status = Disconnected;
 	return ret;
 }

 /**
  * p9_fd_write - write to a socket
  * @v9ses: session information
  * @v: buffer to send data from
  * @len: size of send buffer
  *
  */
 static int p9_fd_write(struct p9_trans *trans, void *v, int len)
 {
 	int ret;
 	mm_segment_t oldfs;
 	struct p9_trans_fd *ts = NULL;

 	if (trans && trans->status != Disconnected)
 		ts = trans->priv;

 	if (!ts)
 		return -EREMOTEIO;

 	if (!(ts->wr->f_flags & O_NONBLOCK))
 		P9_DPRINTK(P9_DEBUG_ERROR, "blocking write ...\n");

 	oldfs = get_fs();
 	set_fs(get_ds());
 	/* The cast to a user pointer is valid due to the set_fs() */
 	ret = vfs_write(ts->wr, (void __user *)v, len, &ts->wr->f_pos);
 	set_fs(oldfs);

 	if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
 		trans->status = Disconnected;
 	return ret;
 }

 static unsigned int
 p9_fd_poll(struct p9_trans *trans, struct poll_table_struct *pt)
 {
 	int ret, n;
 	struct p9_trans_fd *ts = NULL;
 	mm_segment_t oldfs;

 	if (trans && trans->status == Connected)
 		ts = trans->priv;

 	if (!ts)
 		return -EREMOTEIO;

 	if (!ts->rd->f_op || !ts->rd->f_op->poll)
 		return -EIO;

 	if (!ts->wr->f_op || !ts->wr->f_op->poll)
 		return -EIO;

 	oldfs = get_fs();
 	set_fs(get_ds());

 	ret = ts->rd->f_op->poll(ts->rd, pt);
 	if (ret < 0)
 		goto end;

 	if (ts->rd != ts->wr) {
 		n = ts->wr->f_op->poll(ts->wr, pt);
 		if (n < 0) {
 			ret = n;
 			goto end;
 		}
 		ret = (ret & ~POLLOUT) | (n & ~POLLIN);
 	}

 end:
 	set_fs(oldfs);
 	return ret;
 }

 /**
  * p9_sock_close - shutdown socket
  * @trans: private socket structure
  *
  */
 static void p9_fd_close(struct p9_trans *trans)
 {
 	struct p9_trans_fd *ts;

 	if (!trans)
 		return;

 	ts = xchg(&trans->priv, NULL);

 	if (!ts)
 		return;

 	trans->status = Disconnected;
 	if (ts->rd)
 		fput(ts->rd);
 	if (ts->wr)
 		fput(ts->wr);
 	kfree(ts);
 }

 static struct p9_trans *p9_trans_create_tcp(const char *addr, char *args)
 {
 	int err;
 	struct p9_trans *trans;
 	struct socket *csocket;
 	struct sockaddr_in sin_server;
 	struct p9_fd_opts opts;

 	parse_opts(args, &opts);

 	csocket = NULL;
 	trans = kmalloc(sizeof(struct p9_trans), GFP_KERNEL);
 	if (!trans)
 		return ERR_PTR(-ENOMEM);

 	trans->write = p9_fd_write;
 	trans->read = p9_fd_read;
 	trans->close = p9_fd_close;
 	trans->poll = p9_fd_poll;

 	sin_server.sin_family = AF_INET;
 	sin_server.sin_addr.s_addr = in_aton(addr);
 	sin_server.sin_port = htons(opts.port);
 	sock_create_kern(PF_INET, SOCK_STREAM, IPPROTO_TCP, &csocket);

 	if (!csocket) {
 		P9_EPRINTK(KERN_ERR, "p9_trans_tcp: problem creating socket\n");
 		err = -EIO;
 		goto error;
 	}

 	err = csocket->ops->connect(csocket,
 				    (struct sockaddr *)&sin_server,
 				    sizeof(struct sockaddr_in), 0);
 	if (err < 0) {
 		P9_EPRINTK(KERN_ERR,
 			"p9_trans_tcp: problem connecting socket to %s\n",
 			addr);
 		goto error;
 	}

 	err = p9_socket_open(trans, csocket);
 	if (err < 0)
 		goto error;

 	return trans;

 error:
 	if (csocket)
 		sock_release(csocket);

 	kfree(trans);
 	return ERR_PTR(err);
 }

 static struct p9_trans *p9_trans_create_unix(const char *addr, char *args)
 {
 	int err;
 	struct socket *csocket;
 	struct sockaddr_un sun_server;
 	struct p9_trans *trans;

 	csocket = NULL;
 	trans = kmalloc(sizeof(struct p9_trans), GFP_KERNEL);
 	if (!trans)
 		return ERR_PTR(-ENOMEM);

 	trans->write = p9_fd_write;
 	trans->read = p9_fd_read;
 	trans->close = p9_fd_close;
 	trans->poll = p9_fd_poll;

 	if (strlen(addr) > UNIX_PATH_MAX) {
 		P9_EPRINTK(KERN_ERR, "p9_trans_unix: address too long: %s\n",
 			addr);
 		err = -ENAMETOOLONG;
 		goto error;
 	}

 	sun_server.sun_family = PF_UNIX;
 	strcpy(sun_server.sun_path, addr);
 	sock_create_kern(PF_UNIX, SOCK_STREAM, 0, &csocket);
 	err = csocket->ops->connect(csocket, (struct sockaddr *)&sun_server,
 			sizeof(struct sockaddr_un) - 1, 0);
 	if (err < 0) {
 		P9_EPRINTK(KERN_ERR,
 			"p9_trans_unix: problem connecting socket: %s: %d\n",
 			addr, err);
 		goto error;
 	}

 	err = p9_socket_open(trans, csocket);
 	if (err < 0)
 		goto error;

 	return trans;

 error:
 	if (csocket)
 		sock_release(csocket);

 	kfree(trans);
 	return ERR_PTR(err);
 }

 static struct p9_trans *p9_trans_create_fd(const char *name, char *args)
 {
 	int err;
 	struct p9_trans *trans;
 	struct p9_fd_opts opts;

 	parse_opts(args, &opts);

 	if (opts.rfd == ~0 || opts.wfd == ~0) {
 		printk(KERN_ERR "v9fs: Insufficient options for proto=fd\n");
 		return ERR_PTR(-ENOPROTOOPT);
 	}

 	trans = kmalloc(sizeof(struct p9_trans), GFP_KERNEL);
 	if (!trans)
 		return ERR_PTR(-ENOMEM);

 	trans->write = p9_fd_write;
 	trans->read = p9_fd_read;
 	trans->close = p9_fd_close;
 	trans->poll = p9_fd_poll;

 	err = p9_fd_open(trans, opts.rfd, opts.wfd);
 	if (err < 0)
 		goto error;

 	return trans;

 error:
 	kfree(trans);
 	return ERR_PTR(err);
 }

 static struct p9_trans_module p9_tcp_trans = {
 	.name = "tcp",
 	.maxsize = MAX_SOCK_BUF,
 	.def = 1,
 	.create = p9_trans_create_tcp,
 };

 static struct p9_trans_module p9_unix_trans = {
 	.name = "unix",
 	.maxsize = MAX_SOCK_BUF,
 	.def = 0,
 	.create = p9_trans_create_unix,
 };

 static struct p9_trans_module p9_fd_trans = {
 	.name = "fd",
 	.maxsize = MAX_SOCK_BUF,
 	.def = 0,
 	.create = p9_trans_create_fd,
 };

 static int __init p9_trans_fd_init(void)
 {
 	v9fs_register_trans(&p9_tcp_trans);
 	v9fs_register_trans(&p9_unix_trans);
 	v9fs_register_trans(&p9_fd_trans);

 	return 1;
 }

 static void __exit p9_trans_fd_exit(void) {
 	printk(KERN_ERR "Removal of 9p transports not implemented\n");
 	BUG();
 }

 module_init(p9_trans_fd_init);
 module_exit(p9_trans_fd_exit);

 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 MODULE_LICENSE("GPL");
	/*
	* linux/fs/9p/trans_fd.c
	*
	* Fd transport layer. Includes deprecated socket layer.
	*
	* Copyright (C) 2006 by Russ Cox <rsc@swtch.com>
	* Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net>
	* Copyright (C) 2004-2007 by Eric Van Hensbergen <ericvh@gmail.com>
	* Copyright (C) 1997-2002 by Ron Minnich <rminnich@sarnoff.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2
	* as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to:
	* Free Software Foundation
	* 51 Franklin Street, Fifth Floor
	* Boston, MA 02111-1301 USA
	*
	*/

	#include <linux/in.h>
	#include <linux/module.h>
	#include <linux/net.h>
	#include <linux/ipv6.h>
	#include <linux/errno.h>
	#include <linux/kernel.h>
	#include <linux/un.h>
	#include <linux/uaccess.h>
	#include <linux/inet.h>
	#include <linux/idr.h>
	#include <linux/file.h>
	#include <linux/parser.h>
	#include <net/9p/9p.h>
	#include <net/9p/transport.h>

	#define P9_PORT 564
	#define MAX_SOCK_BUF (64*1024)


	struct p9_fd_opts {
	int rfd;
	int wfd;
	u16 port;
	};

	struct p9_trans_fd {
	struct file *rd;
	struct file *wr;
	};

	/*
	* Option Parsing (code inspired by NFS code)
	* - a little lazy - parse all fd-transport options
	*/

	enum {
	/* Options that take integer arguments */
	Opt_port, Opt_rfdno, Opt_wfdno, Opt_err,
	};

	static match_table_t tokens = {
	{Opt_port, "port=%u"},
	{Opt_rfdno, "rfdno=%u"},
	{Opt_wfdno, "wfdno=%u"},
	{Opt_err, NULL},
	};

	/**
	* v9fs_parse_options - parse mount options into session structure
	* @options: options string passed from mount
	* @v9ses: existing v9fs session information
	*
	*/

	static void parse_opts(char options, struct p9_fd_opts opts)
	{
	char *p;
	substring_t args[MAX_OPT_ARGS];
	int option;
	int ret;

	opts->port = P9_PORT;
	opts->rfd = ~0;
	opts->wfd = ~0;

	if (!options)
	return;

	while ((p = strsep(&options, ",")) != NULL) {
	int token;
	if (!*p)
	continue;
	token = match_token(p, tokens, args);
	ret = match_int(&args[0], &option);
	if (ret < 0) {
	P9_DPRINTK(P9_DEBUG_ERROR,
	"integer field, but no integer?\n");
	continue;
	}
	switch (token) {
	case Opt_port:
	opts->port = option;
	break;
	case Opt_rfdno:
	opts->rfd = option;
	break;
	case Opt_wfdno:
	opts->wfd = option;
	break;
	default:
	continue;
	}
	}
	}

	static int p9_fd_open(struct p9_trans *trans, int rfd, int wfd)
	{
	struct p9_trans_fd *ts = kmalloc(sizeof(struct p9_trans_fd),
	GFP_KERNEL);
	if (!ts)
	return -ENOMEM;

	ts->rd = fget(rfd);
	ts->wr = fget(wfd);
	if (!ts->rd \|\| !ts->wr) {
	if (ts->rd)
	fput(ts->rd);
	if (ts->wr)
	fput(ts->wr);
	kfree(ts);
	return -EIO;
	}

	trans->priv = ts;
	trans->status = Connected;

	return 0;
	}

	static int p9_socket_open(struct p9_trans trans, struct socket csocket)
	{
	int fd, ret;

	csocket->sk->sk_allocation = GFP_NOIO;
	fd = sock_map_fd(csocket);
	if (fd < 0) {
	P9_EPRINTK(KERN_ERR, "p9_socket_open: failed to map fd\n");
	return fd;
	}

	ret = p9_fd_open(trans, fd, fd);
	if (ret < 0) {
	P9_EPRINTK(KERN_ERR, "p9_socket_open: failed to open fd\n");
	sockfd_put(csocket);
	return ret;
	}

	((struct p9_trans_fd *)trans->priv)->rd->f_flags \|= O_NONBLOCK;

	return 0;
	}

	/**
	* p9_fd_read- read from a fd
	* @v9ses: session information
	* @v: buffer to receive data into
	* @len: size of receive buffer
	*
	*/
	static int p9_fd_read(struct p9_trans trans, void v, int len)
	{
	int ret;
	struct p9_trans_fd *ts = NULL;

	if (trans && trans->status != Disconnected)
	ts = trans->priv;

	if (!ts)
	return -EREMOTEIO;

	if (!(ts->rd->f_flags & O_NONBLOCK))
	P9_DPRINTK(P9_DEBUG_ERROR, "blocking read ...\n");

	ret = kernel_read(ts->rd, ts->rd->f_pos, v, len);
	if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
	trans->status = Disconnected;
	return ret;
	}

	/**
	* p9_fd_write - write to a socket
	* @v9ses: session information
	* @v: buffer to send data from
	* @len: size of send buffer
	*
	*/
	static int p9_fd_write(struct p9_trans trans, void v, int len)
	{
	int ret;
	mm_segment_t oldfs;
	struct p9_trans_fd *ts = NULL;

	if (trans && trans->status != Disconnected)
	ts = trans->priv;

	if (!ts)
	return -EREMOTEIO;

	if (!(ts->wr->f_flags & O_NONBLOCK))
	P9_DPRINTK(P9_DEBUG_ERROR, "blocking write ...\n");

	oldfs = get_fs();
	set_fs(get_ds());
	/* The cast to a user pointer is valid due to the set_fs() */
	ret = vfs_write(ts->wr, (void __user *)v, len, &ts->wr->f_pos);
	set_fs(oldfs);

	if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
	trans->status = Disconnected;
	return ret;
	}

	static unsigned int
	p9_fd_poll(struct p9_trans trans, struct poll_table_struct pt)
	{
	int ret, n;
	struct p9_trans_fd *ts = NULL;
	mm_segment_t oldfs;

	if (trans && trans->status == Connected)
	ts = trans->priv;

	if (!ts)
	return -EREMOTEIO;

	if (!ts->rd->f_op \|\| !ts->rd->f_op->poll)
	return -EIO;

	if (!ts->wr->f_op \|\| !ts->wr->f_op->poll)
	return -EIO;

	oldfs = get_fs();
	set_fs(get_ds());

	ret = ts->rd->f_op->poll(ts->rd, pt);
	if (ret < 0)
	goto end;

	if (ts->rd != ts->wr) {
	n = ts->wr->f_op->poll(ts->wr, pt);
	if (n < 0) {
	ret = n;
	goto end;
	}
	ret = (ret & ~POLLOUT) \| (n & ~POLLIN);
	}

	end:
	set_fs(oldfs);
	return ret;
	}

	/**
	* p9_sock_close - shutdown socket
	* @trans: private socket structure
	*
	*/
	static void p9_fd_close(struct p9_trans *trans)
	{
	struct p9_trans_fd *ts;

	if (!trans)
	return;

	ts = xchg(&trans->priv, NULL);

	if (!ts)
	return;

	trans->status = Disconnected;
	if (ts->rd)
	fput(ts->rd);
	if (ts->wr)
	fput(ts->wr);
	kfree(ts);
	}

	static struct p9_trans p9_trans_create_tcp(const char addr, char *args)
	{
	int err;
	struct p9_trans *trans;
	struct socket *csocket;
	struct sockaddr_in sin_server;
	struct p9_fd_opts opts;

	parse_opts(args, &opts);

	csocket = NULL;
	trans = kmalloc(sizeof(struct p9_trans), GFP_KERNEL);
	if (!trans)
	return ERR_PTR(-ENOMEM);

	trans->write = p9_fd_write;
	trans->read = p9_fd_read;
	trans->close = p9_fd_close;
	trans->poll = p9_fd_poll;

	sin_server.sin_family = AF_INET;
	sin_server.sin_addr.s_addr = in_aton(addr);
	sin_server.sin_port = htons(opts.port);
	sock_create_kern(PF_INET, SOCK_STREAM, IPPROTO_TCP, &csocket);

	if (!csocket) {
	P9_EPRINTK(KERN_ERR, "p9_trans_tcp: problem creating socket\n");
	err = -EIO;
	goto error;
	}

	err = csocket->ops->connect(csocket,
	(struct sockaddr *)&sin_server,
	sizeof(struct sockaddr_in), 0);
	if (err < 0) {
	P9_EPRINTK(KERN_ERR,
	"p9_trans_tcp: problem connecting socket to %s\n",
	addr);
	goto error;
	}

	err = p9_socket_open(trans, csocket);
	if (err < 0)
	goto error;

	return trans;

	error:
	if (csocket)
	sock_release(csocket);

	kfree(trans);
	return ERR_PTR(err);
	}

	static struct p9_trans p9_trans_create_unix(const char addr, char *args)
	{
	int err;
	struct socket *csocket;
	struct sockaddr_un sun_server;
	struct p9_trans *trans;

	csocket = NULL;
	trans = kmalloc(sizeof(struct p9_trans), GFP_KERNEL);
	if (!trans)
	return ERR_PTR(-ENOMEM);

	trans->write = p9_fd_write;
	trans->read = p9_fd_read;
	trans->close = p9_fd_close;
	trans->poll = p9_fd_poll;

	if (strlen(addr) > UNIX_PATH_MAX) {
	P9_EPRINTK(KERN_ERR, "p9_trans_unix: address too long: %s\n",
	addr);
	err = -ENAMETOOLONG;
	goto error;
	}

	sun_server.sun_family = PF_UNIX;
	strcpy(sun_server.sun_path, addr);
	sock_create_kern(PF_UNIX, SOCK_STREAM, 0, &csocket);
	err = csocket->ops->connect(csocket, (struct sockaddr *)&sun_server,
	sizeof(struct sockaddr_un) - 1, 0);
	if (err < 0) {
	P9_EPRINTK(KERN_ERR,
	"p9_trans_unix: problem connecting socket: %s: %d\n",
	addr, err);
	goto error;
	}

	err = p9_socket_open(trans, csocket);
	if (err < 0)
	goto error;

	return trans;

	error:
	if (csocket)
	sock_release(csocket);

	kfree(trans);
	return ERR_PTR(err);
	}

	static struct p9_trans p9_trans_create_fd(const char name, char *args)
	{
	int err;
	struct p9_trans *trans;
	struct p9_fd_opts opts;

	parse_opts(args, &opts);

	if (opts.rfd == ~0 \|\| opts.wfd == ~0) {
	printk(KERN_ERR "v9fs: Insufficient options for proto=fd\n");
	return ERR_PTR(-ENOPROTOOPT);
	}

	trans = kmalloc(sizeof(struct p9_trans), GFP_KERNEL);
	if (!trans)
	return ERR_PTR(-ENOMEM);

	trans->write = p9_fd_write;
	trans->read = p9_fd_read;
	trans->close = p9_fd_close;
	trans->poll = p9_fd_poll;

	err = p9_fd_open(trans, opts.rfd, opts.wfd);
	if (err < 0)
	goto error;

	return trans;

	error:
	kfree(trans);
	return ERR_PTR(err);
	}

	static struct p9_trans_module p9_tcp_trans = {
	.name = "tcp",
	.maxsize = MAX_SOCK_BUF,
	.def = 1,
	.create = p9_trans_create_tcp,
	};

	static struct p9_trans_module p9_unix_trans = {
	.name = "unix",
	.maxsize = MAX_SOCK_BUF,
	.def = 0,
	.create = p9_trans_create_unix,
	};

	static struct p9_trans_module p9_fd_trans = {
	.name = "fd",
	.maxsize = MAX_SOCK_BUF,
	.def = 0,
	.create = p9_trans_create_fd,
	};

	static int __init p9_trans_fd_init(void)
	{
	v9fs_register_trans(&p9_tcp_trans);
	v9fs_register_trans(&p9_unix_trans);
	v9fs_register_trans(&p9_fd_trans);

	return 1;
	}

	static void __exit p9_trans_fd_exit(void) {
	printk(KERN_ERR "Removal of 9p transports not implemented\n");
	BUG();
	}

	module_init(p9_trans_fd_init);
	module_exit(p9_trans_fd_exit);

	MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
	MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
	MODULE_LICENSE("GPL");