net/9p/trans_fd.c

   1 /*
   2  * linux/fs/9p/trans_fd.c
   3  *
   4  * Fd transport layer.  Includes deprecated socket layer.
   5  *
   6  *  Copyright (C) 2006 by Russ Cox <rsc@swtch.com>
   7  *  Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net>
   8  *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
   9  *  Copyright (C) 1997-2002 by Ron Minnich <rminnich@sarnoff.com>
  10  *
  11  *  This program is free software; you can redistribute it and/or modify
  12  *  it under the terms of the GNU General Public License version 2
  13  *  as published by the Free Software Foundation.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to:
  22  *  Free Software Foundation
  23  *  51 Franklin Street, Fifth Floor
  24  *  Boston, MA  02111-1301  USA
  25  *
  26  */
  27
  28 #include <linux/in.h>
  29 #include <linux/module.h>
  30 #include <linux/net.h>
  31 #include <linux/ipv6.h>
  32 #include <linux/kthread.h>
  33 #include <linux/errno.h>
  34 #include <linux/kernel.h>
  35 #include <linux/un.h>
  36 #include <linux/uaccess.h>
  37 #include <linux/inet.h>
  38 #include <linux/idr.h>
  39 #include <linux/file.h>
  40 #include <linux/parser.h>
  41 #include <net/9p/9p.h>
  42 #include <net/9p/client.h>
  43 #include <net/9p/transport.h>
  44
  45 #define P9_PORT 564
  46 #define MAX_SOCK_BUF (64*1024)
  47 #define ERREQFLUSH      1
  48 #define MAXPOLLWADDR    2
  49
  50 /**
  51  * struct p9_fd_opts - per-transport options
  52  * @rfd: file descriptor for reading (trans=fd)
  53  * @wfd: file descriptor for writing (trans=fd)
  54  * @port: port to connect to (trans=tcp)
  55  *
  56  */
  57
  58 struct p9_fd_opts {
  59         int rfd;
  60         int wfd;
  61         u16 port;
  62 };
  63
  64 /**
  65  * struct p9_trans_fd - transport state
  66  * @rd: reference to file to read from
  67  * @wr: reference of file to write to
  68  * @conn: connection state reference
  69  *
  70  */
  71
  72 struct p9_trans_fd {
  73         struct file *rd;
  74         struct file *wr;
  75         struct p9_conn *conn;
  76 };
  77
  78 /*
  79   * Option Parsing (code inspired by NFS code)
  80   *  - a little lazy - parse all fd-transport options
  81   */
  82
  83 enum {
  84         /* Options that take integer arguments */
  85         Opt_port, Opt_rfdno, Opt_wfdno, Opt_err,
  86 };
  87
  88 static const match_table_t tokens = {
  89         {Opt_port, "port=%u"},
  90         {Opt_rfdno, "rfdno=%u"},
  91         {Opt_wfdno, "wfdno=%u"},
  92         {Opt_err, NULL},
  93 };
  94
  95 enum {
  96         Rworksched = 1,         /* read work scheduled or running */
  97         Rpending = 2,           /* can read */
  98         Wworksched = 4,         /* write work scheduled or running */
  99         Wpending = 8,           /* can write */
 100 };
 101
 102 enum {
 103         None,
 104         Flushing,
 105         Flushed,
 106 };
 107
 108 struct p9_req;
 109 typedef void (*p9_conn_req_callback)(struct p9_req *req, void *a);
 110
 111 /**
 112  * struct p9_req - fd mux encoding of an rpc transaction
 113  * @lock: protects req_list
 114  * @tag: numeric tag for rpc transaction
 115  * @tcall: request &p9_fcall structure
 116  * @rcall: response &p9_fcall structure
 117  * @err: error state
 118  * @cb: callback for when response is received
 119  * @cba: argument to pass to callback
 120  * @flush: flag to indicate RPC has been flushed
 121  * @req_list: list link for higher level objects to chain requests
 122  * @m: connection this request was issued on
 123  * @wqueue: wait queue that client is blocked on for this rpc
 124  *
 125  */
 126
 127 struct p9_req {
 128         spinlock_t lock;
 129         int tag;
 130         struct p9_fcall *tcall;
 131         struct p9_fcall *rcall;
 132         int err;
 133         p9_conn_req_callback cb;
 134         void *cba;
 135         int flush;
 136         struct list_head req_list;
 137         struct p9_conn *m;
 138         wait_queue_head_t wqueue;
 139 };
 140
 141 struct p9_poll_wait {
 142         struct p9_conn *conn;
 143         wait_queue_t wait;
 144         wait_queue_head_t *wait_addr;
 145 };
 146
 147 /**
 148  * struct p9_conn - fd mux connection state information
 149  * @lock: protects mux_list (?)
 150  * @mux_list: list link for mux to manage multiple connections (?)
 151  * @client: reference to client instance for this connection
 152  * @tagpool: id accounting for transactions
 153  * @err: error state
 154  * @req_list: accounting for requests which have been sent
 155  * @unsent_req_list: accounting for requests that haven't been sent
 156  * @rcall: current response &p9_fcall structure
 157  * @rpos: read position in current frame
 158  * @rbuf: current read buffer
 159  * @wpos: write position for current frame
 160  * @wsize: amount of data to write for current frame
 161  * @wbuf: current write buffer
 162  * @poll_wait: array of wait_q's for various worker threads
 163  * @poll_waddr: ????
 164  * @pt: poll state
 165  * @rq: current read work
 166  * @wq: current write work
 167  * @wsched: ????
 168  *
 169  */
 170
 171 struct p9_conn {
 172         spinlock_t lock; /* protect lock structure */
 173         struct list_head mux_list;
 174         struct p9_client *client;
 175         struct p9_idpool *tagpool;
 176         int err;
 177         struct list_head req_list;
 178         struct list_head unsent_req_list;
 179         struct p9_fcall *rcall;
 180         int rpos;
 181         char *rbuf;
 182         int wpos;
 183         int wsize;
 184         char *wbuf;
 185         struct list_head poll_pending_link;
 186         struct p9_poll_wait poll_wait[MAXPOLLWADDR];
 187         poll_table pt;
 188         struct work_struct rq;
 189         struct work_struct wq;
 190         unsigned long wsched;
 191 };
 192
 193 static DEFINE_SPINLOCK(p9_poll_lock);
 194 static LIST_HEAD(p9_poll_pending_list);
 195 static struct workqueue_struct *p9_mux_wq;
 196 static struct task_struct *p9_poll_task;
 197
 198 static u16 p9_mux_get_tag(struct p9_conn *m)
 199 {
 200         int tag;
 201
 202         tag = p9_idpool_get(m->tagpool);
 203         if (tag < 0)
 204                 return P9_NOTAG;
 205         else
 206                 return (u16) tag;
 207 }
 208
 209 static void p9_mux_put_tag(struct p9_conn *m, u16 tag)
 210 {
 211         if (tag != P9_NOTAG && p9_idpool_check(tag, m->tagpool))
 212                 p9_idpool_put(tag, m->tagpool);
 213 }
 214
 215 static void p9_mux_poll_stop(struct p9_conn *m)
 216 {
 217         unsigned long flags;
 218         int i;
 219
 220         for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
 221                 struct p9_poll_wait *pwait = &m->poll_wait[i];
 222
 223                 if (pwait->wait_addr) {
 224                         remove_wait_queue(pwait->wait_addr, &pwait->wait);
 225                         pwait->wait_addr = NULL;
 226                 }
 227         }
 228
 229         spin_lock_irqsave(&p9_poll_lock, flags);
 230         list_del_init(&m->poll_pending_link);
 231         spin_unlock_irqrestore(&p9_poll_lock, flags);
 232 }
 233
 234 /**
 235  * p9_conn_cancel - cancel all pending requests with error
 236  * @m: mux data
 237  * @err: error code
 238  *
 239  */
 240
 241 void p9_conn_cancel(struct p9_conn *m, int err)
 242 {
 243         struct p9_req *req, *rtmp;
 244         LIST_HEAD(cancel_list);
 245
 246         P9_DPRINTK(P9_DEBUG_ERROR, "mux %p err %d\n", m, err);
 247         m->err = err;
 248         spin_lock(&m->lock);
 249         list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
 250                 list_move(&req->req_list, &cancel_list);
 251         }
 252         list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) {
 253                 list_move(&req->req_list, &cancel_list);
 254         }
 255         spin_unlock(&m->lock);
 256
 257         list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
 258                 list_del(&req->req_list);
 259                 if (!req->err)
 260                         req->err = err;
 261
 262                 if (req->cb)
 263                         (*req->cb) (req, req->cba);
 264                 else
 265                         kfree(req->rcall);
 266         }
 267 }
 268
 269 static void process_request(struct p9_conn *m, struct p9_req *req)
 270 {
 271         int ecode;
 272         struct p9_str *ename;
 273
 274         if (!req->err && req->rcall->id == P9_RERROR) {
 275                 ecode = req->rcall->params.rerror.errno;
 276                 ename = &req->rcall->params.rerror.error;
 277
 278                 P9_DPRINTK(P9_DEBUG_MUX, "Rerror %.*s\n", ename->len,
 279                                                                 ename->str);
 280
 281                 if (m->client->dotu)
 282                         req->err = -ecode;
 283
 284                 if (!req->err) {
 285                         req->err = p9_errstr2errno(ename->str, ename->len);
 286
 287                         /* string match failed */
 288                         if (!req->err) {
 289                                 PRINT_FCALL_ERROR("unknown error", req->rcall);
 290                                 req->err = -ESERVERFAULT;
 291                         }
 292                 }
 293         } else if (req->tcall && req->rcall->id != req->tcall->id + 1) {
 294                 P9_DPRINTK(P9_DEBUG_ERROR,
 295                                 "fcall mismatch: expected %d, got %d\n",
 296                                 req->tcall->id + 1, req->rcall->id);
 297                 if (!req->err)
 298                         req->err = -EIO;
 299         }
 300 }
 301
 302 static unsigned int
 303 p9_fd_poll(struct p9_client *client, struct poll_table_struct *pt)
 304 {
 305         int ret, n;
 306         struct p9_trans_fd *ts = NULL;
 307
 308         if (client && client->status == Connected)
 309                 ts = client->trans;
 310
 311         if (!ts)
 312                 return -EREMOTEIO;
 313
 314         if (!ts->rd->f_op || !ts->rd->f_op->poll)
 315                 return -EIO;
 316
 317         if (!ts->wr->f_op || !ts->wr->f_op->poll)
 318                 return -EIO;
 319
 320         ret = ts->rd->f_op->poll(ts->rd, pt);
 321         if (ret < 0)
 322                 return ret;
 323
 324         if (ts->rd != ts->wr) {
 325                 n = ts->wr->f_op->poll(ts->wr, pt);
 326                 if (n < 0)
 327                         return n;
 328                 ret = (ret & ~POLLOUT) | (n & ~POLLIN);
 329         }
 330
 331         return ret;
 332 }
 333
 334 /**
 335  * p9_fd_read- read from a fd
 336  * @client: client instance
 337  * @v: buffer to receive data into
 338  * @len: size of receive buffer
 339  *
 340  */
 341
 342 static int p9_fd_read(struct p9_client *client, void *v, int len)
 343 {
 344         int ret;
 345         struct p9_trans_fd *ts = NULL;
 346
 347         if (client && client->status != Disconnected)
 348                 ts = client->trans;
 349
 350         if (!ts)
 351                 return -EREMOTEIO;
 352
 353         if (!(ts->rd->f_flags & O_NONBLOCK))
 354                 P9_DPRINTK(P9_DEBUG_ERROR, "blocking read ...\n");
 355
 356         ret = kernel_read(ts->rd, ts->rd->f_pos, v, len);
 357         if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
 358                 client->status = Disconnected;
 359         return ret;
 360 }
 361
 362 /**
 363  * p9_read_work - called when there is some data to be read from a transport
 364  * @work: container of work to be done
 365  *
 366  */
 367
 368 static void p9_read_work(struct work_struct *work)
 369 {
 370         int n, err;
 371         struct p9_conn *m;
 372         struct p9_req *req, *rptr, *rreq;
 373         struct p9_fcall *rcall;
 374         char *rbuf;
 375
 376         m = container_of(work, struct p9_conn, rq);
 377
 378         if (m->err < 0)
 379                 return;
 380
 381         rcall = NULL;
 382         P9_DPRINTK(P9_DEBUG_MUX, "start mux %p pos %d\n", m, m->rpos);
 383
 384         if (!m->rcall) {
 385                 m->rcall =
 386                     kmalloc(sizeof(struct p9_fcall) + m->client->msize,
 387                                                                 GFP_KERNEL);
 388                 if (!m->rcall) {
 389                         err = -ENOMEM;
 390                         goto error;
 391                 }
 392
 393                 m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
 394                 m->rpos = 0;
 395         }
 396
 397         clear_bit(Rpending, &m->wsched);
 398         err = p9_fd_read(m->client, m->rbuf + m->rpos,
 399                                                 m->client->msize - m->rpos);
 400         P9_DPRINTK(P9_DEBUG_MUX, "mux %p got %d bytes\n", m, err);
 401         if (err == -EAGAIN) {
 402                 clear_bit(Rworksched, &m->wsched);
 403                 return;
 404         }
 405
 406         if (err <= 0)
 407                 goto error;
 408
 409         m->rpos += err;
 410         while (m->rpos > 4) {
 411                 n = le32_to_cpu(*(__le32 *) m->rbuf);
 412                 if (n >= m->client->msize) {
 413                         P9_DPRINTK(P9_DEBUG_ERROR,
 414                                 "requested packet size too big: %d\n", n);
 415                         err = -EIO;
 416                         goto error;
 417                 }
 418
 419                 if (m->rpos < n)
 420                         break;
 421
 422                 err =
 423                     p9_deserialize_fcall(m->rbuf, n, m->rcall, m->client->dotu);
 424                 if (err < 0)
 425                         goto error;
 426
 427 #ifdef CONFIG_NET_9P_DEBUG
 428                 if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
 429                         char buf[150];
 430
 431                         p9_printfcall(buf, sizeof(buf), m->rcall,
 432                                 m->client->dotu);
 433                         printk(KERN_NOTICE ">>> %p %s\n", m, buf);
 434                 }
 435 #endif
 436
 437                 rcall = m->rcall;
 438                 rbuf = m->rbuf;
 439                 if (m->rpos > n) {
 440                         m->rcall = kmalloc(sizeof(struct p9_fcall) +
 441                                                 m->client->msize, GFP_KERNEL);
 442                         if (!m->rcall) {
 443                                 err = -ENOMEM;
 444                                 goto error;
 445                         }
 446
 447                         m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
 448                         memmove(m->rbuf, rbuf + n, m->rpos - n);
 449                         m->rpos -= n;
 450                 } else {
 451                         m->rcall = NULL;
 452                         m->rbuf = NULL;
 453                         m->rpos = 0;
 454                 }
 455
 456                 P9_DPRINTK(P9_DEBUG_MUX, "mux %p fcall id %d tag %d\n", m,
 457                                                         rcall->id, rcall->tag);
 458
 459                 req = NULL;
 460                 spin_lock(&m->lock);
 461                 list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
 462                         if (rreq->tag == rcall->tag) {
 463                                 req = rreq;
 464                                 if (req->flush != Flushing)
 465                                         list_del(&req->req_list);
 466                                 break;
 467                         }
 468                 }
 469                 spin_unlock(&m->lock);
 470
 471                 if (req) {
 472                         req->rcall = rcall;
 473                         process_request(m, req);
 474
 475                         if (req->flush != Flushing) {
 476                                 if (req->cb)
 477                                         (*req->cb) (req, req->cba);
 478                                 else
 479                                         kfree(req->rcall);
 480                         }
 481                 } else {
 482                         if (err >= 0 && rcall->id != P9_RFLUSH)
 483                                 P9_DPRINTK(P9_DEBUG_ERROR,
 484                                   "unexpected response mux %p id %d tag %d\n",
 485                                   m, rcall->id, rcall->tag);
 486                         kfree(rcall);
 487                 }
 488         }
 489
 490         if (!list_empty(&m->req_list)) {
 491                 if (test_and_clear_bit(Rpending, &m->wsched))
 492                         n = POLLIN;
 493                 else
 494                         n = p9_fd_poll(m->client, NULL);
 495
 496                 if (n & POLLIN) {
 497                         P9_DPRINTK(P9_DEBUG_MUX, "schedule read work %p\n", m);
 498                         queue_work(p9_mux_wq, &m->rq);
 499                 } else
 500                         clear_bit(Rworksched, &m->wsched);
 501         } else
 502                 clear_bit(Rworksched, &m->wsched);
 503
 504         return;
 505
 506 error:
 507         p9_conn_cancel(m, err);
 508         clear_bit(Rworksched, &m->wsched);
 509 }
 510
 511 /**
 512  * p9_fd_write - write to a socket
 513  * @client: client instance
 514  * @v: buffer to send data from
 515  * @len: size of send buffer
 516  *
 517  */
 518
 519 static int p9_fd_write(struct p9_client *client, void *v, int len)
 520 {
 521         int ret;
 522         mm_segment_t oldfs;
 523         struct p9_trans_fd *ts = NULL;
 524
 525         if (client && client->status != Disconnected)
 526                 ts = client->trans;
 527
 528         if (!ts)
 529                 return -EREMOTEIO;
 530
 531         if (!(ts->wr->f_flags & O_NONBLOCK))
 532                 P9_DPRINTK(P9_DEBUG_ERROR, "blocking write ...\n");
 533
 534         oldfs = get_fs();
 535         set_fs(get_ds());
 536         /* The cast to a user pointer is valid due to the set_fs() */
 537         ret = vfs_write(ts->wr, (void __user *)v, len, &ts->wr->f_pos);
 538         set_fs(oldfs);
 539
 540         if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
 541                 client->status = Disconnected;
 542         return ret;
 543 }
 544
 545 /**
 546  * p9_write_work - called when a transport can send some data
 547  * @work: container for work to be done
 548  *
 549  */
 550
 551 static void p9_write_work(struct work_struct *work)
 552 {
 553         int n, err;
 554         struct p9_conn *m;
 555         struct p9_req *req;
 556
 557         m = container_of(work, struct p9_conn, wq);
 558
 559         if (m->err < 0) {
 560                 clear_bit(Wworksched, &m->wsched);
 561                 return;
 562         }
 563
 564         if (!m->wsize) {
 565                 if (list_empty(&m->unsent_req_list)) {
 566                         clear_bit(Wworksched, &m->wsched);
 567                         return;
 568                 }
 569
 570                 spin_lock(&m->lock);
 571 again:
 572                 req = list_entry(m->unsent_req_list.next, struct p9_req,
 573                                req_list);
 574                 list_move_tail(&req->req_list, &m->req_list);
 575                 if (req->err == ERREQFLUSH)
 576                         goto again;
 577
 578                 m->wbuf = req->tcall->sdata;
 579                 m->wsize = req->tcall->size;
 580                 m->wpos = 0;
 581                 spin_unlock(&m->lock);
 582         }
 583
 584         P9_DPRINTK(P9_DEBUG_MUX, "mux %p pos %d size %d\n", m, m->wpos,
 585                                                                 m->wsize);
 586         clear_bit(Wpending, &m->wsched);
 587         err = p9_fd_write(m->client, m->wbuf + m->wpos, m->wsize - m->wpos);
 588         P9_DPRINTK(P9_DEBUG_MUX, "mux %p sent %d bytes\n", m, err);
 589         if (err == -EAGAIN) {
 590                 clear_bit(Wworksched, &m->wsched);
 591                 return;
 592         }
 593
 594         if (err < 0)
 595                 goto error;
 596         else if (err == 0) {
 597                 err = -EREMOTEIO;
 598                 goto error;
 599         }
 600
 601         m->wpos += err;
 602         if (m->wpos == m->wsize)
 603                 m->wpos = m->wsize = 0;
 604
 605         if (m->wsize == 0 && !list_empty(&m->unsent_req_list)) {
 606                 if (test_and_clear_bit(Wpending, &m->wsched))
 607                         n = POLLOUT;
 608                 else
 609                         n = p9_fd_poll(m->client, NULL);
 610
 611                 if (n & POLLOUT) {
 612                         P9_DPRINTK(P9_DEBUG_MUX, "schedule write work %p\n", m);
 613                         queue_work(p9_mux_wq, &m->wq);
 614                 } else
 615                         clear_bit(Wworksched, &m->wsched);
 616         } else
 617                 clear_bit(Wworksched, &m->wsched);
 618
 619         return;
 620
 621 error:
 622         p9_conn_cancel(m, err);
 623         clear_bit(Wworksched, &m->wsched);
 624 }
 625
 626 static int p9_pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
 627 {
 628         struct p9_poll_wait *pwait =
 629                 container_of(wait, struct p9_poll_wait, wait);
 630         struct p9_conn *m = pwait->conn;
 631         unsigned long flags;
 632         DECLARE_WAITQUEUE(dummy_wait, p9_poll_task);
 633
 634         spin_lock_irqsave(&p9_poll_lock, flags);
 635         if (list_empty(&m->poll_pending_link))
 636                 list_add_tail(&m->poll_pending_link, &p9_poll_pending_list);
 637         spin_unlock_irqrestore(&p9_poll_lock, flags);
 638
 639         /* perform the default wake up operation */
 640         return default_wake_function(&dummy_wait, mode, sync, key);
 641 }
 642
 643 /**
 644  * p9_pollwait - add poll task to the wait queue
 645  * @filp: file pointer being polled
 646  * @wait_address: wait_q to block on
 647  * @p: poll state
 648  *
 649  * called by files poll operation to add v9fs-poll task to files wait queue
 650  */
 651
 652 static void
 653 p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p)
 654 {
 655         struct p9_conn *m = container_of(p, struct p9_conn, pt);
 656         struct p9_poll_wait *pwait = NULL;
 657         int i;
 658
 659         for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
 660                 if (m->poll_wait[i].wait_addr == NULL) {
 661                         pwait = &m->poll_wait[i];
 662                         break;
 663                 }
 664         }
 665
 666         if (!pwait) {
 667                 P9_DPRINTK(P9_DEBUG_ERROR, "not enough wait_address slots\n");
 668                 return;
 669         }
 670
 671         if (!wait_address) {
 672                 P9_DPRINTK(P9_DEBUG_ERROR, "no wait_address\n");
 673                 pwait->wait_addr = ERR_PTR(-EIO);
 674                 return;
 675         }
 676
 677         pwait->conn = m;
 678         pwait->wait_addr = wait_address;
 679         init_waitqueue_func_entry(&pwait->wait, p9_pollwake);
 680         add_wait_queue(wait_address, &pwait->wait);
 681 }
 682
 683 /**
 684  * p9_conn_create - allocate and initialize the per-session mux data
 685  * @client: client instance
 686  *
 687  * Note: Creates the polling task if this is the first session.
 688  */
 689
 690 static struct p9_conn *p9_conn_create(struct p9_client *client)
 691 {
 692         int i, n;
 693         struct p9_conn *m;
 694
 695         P9_DPRINTK(P9_DEBUG_MUX, "client %p msize %d\n", client, client->msize);
 696         m = kzalloc(sizeof(struct p9_conn), GFP_KERNEL);
 697         if (!m)
 698                 return ERR_PTR(-ENOMEM);
 699
 700         spin_lock_init(&m->lock);
 701         INIT_LIST_HEAD(&m->mux_list);
 702         m->client = client;
 703         m->tagpool = p9_idpool_create();
 704         if (IS_ERR(m->tagpool)) {
 705                 kfree(m);
 706                 return ERR_PTR(-ENOMEM);
 707         }
 708
 709         INIT_LIST_HEAD(&m->req_list);
 710         INIT_LIST_HEAD(&m->unsent_req_list);
 711         INIT_WORK(&m->rq, p9_read_work);
 712         INIT_WORK(&m->wq, p9_write_work);
 713         INIT_LIST_HEAD(&m->poll_pending_link);
 714         init_poll_funcptr(&m->pt, p9_pollwait);
 715
 716         n = p9_fd_poll(client, &m->pt);
 717         if (n & POLLIN) {
 718                 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can read\n", m);
 719                 set_bit(Rpending, &m->wsched);
 720         }
 721
 722         if (n & POLLOUT) {
 723                 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can write\n", m);
 724                 set_bit(Wpending, &m->wsched);
 725         }
 726
 727         for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
 728                 if (IS_ERR(m->poll_wait[i].wait_addr)) {
 729                         p9_mux_poll_stop(m);
 730                         kfree(m);
 731                         /* return the error code */
 732                         return (void *)m->poll_wait[i].wait_addr;
 733                 }
 734         }
 735
 736         return m;
 737 }
 738
 739 /**
 740  * p9_poll_mux - polls a mux and schedules read or write works if necessary
 741  * @m: connection to poll
 742  *
 743  */
 744
 745 static void p9_poll_mux(struct p9_conn *m)
 746 {
 747         int n;
 748
 749         if (m->err < 0)
 750                 return;
 751
 752         n = p9_fd_poll(m->client, NULL);
 753         if (n < 0 || n & (POLLERR | POLLHUP | POLLNVAL)) {
 754                 P9_DPRINTK(P9_DEBUG_MUX, "error mux %p err %d\n", m, n);
 755                 if (n >= 0)
 756                         n = -ECONNRESET;
 757                 p9_conn_cancel(m, n);
 758         }
 759
 760         if (n & POLLIN) {
 761                 set_bit(Rpending, &m->wsched);
 762                 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can read\n", m);
 763                 if (!test_and_set_bit(Rworksched, &m->wsched)) {
 764                         P9_DPRINTK(P9_DEBUG_MUX, "schedule read work %p\n", m);
 765                         queue_work(p9_mux_wq, &m->rq);
 766                 }
 767         }
 768
 769         if (n & POLLOUT) {
 770                 set_bit(Wpending, &m->wsched);
 771                 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can write\n", m);
 772                 if ((m->wsize || !list_empty(&m->unsent_req_list))
 773                     && !test_and_set_bit(Wworksched, &m->wsched)) {
 774                         P9_DPRINTK(P9_DEBUG_MUX, "schedule write work %p\n", m);
 775                         queue_work(p9_mux_wq, &m->wq);
 776                 }
 777         }
 778 }
 779
 780 /**
 781  * p9_send_request - send 9P request
 782  * The function can sleep until the request is scheduled for sending.
 783  * The function can be interrupted. Return from the function is not
 784  * a guarantee that the request is sent successfully. Can return errors
 785  * that can be retrieved by PTR_ERR macros.
 786  *
 787  * @m: mux data
 788  * @tc: request to be sent
 789  * @cb: callback function to call when response is received
 790  * @cba: parameter to pass to the callback function
 791  *
 792  */
 793
 794 static struct p9_req *p9_send_request(struct p9_conn *m,
 795                                           struct p9_fcall *tc,
 796                                           p9_conn_req_callback cb, void *cba)
 797 {
 798         int n;
 799         struct p9_req *req;
 800
 801         P9_DPRINTK(P9_DEBUG_MUX, "mux %p task %p tcall %p id %d\n", m, current,
 802                 tc, tc->id);
 803         if (m->err < 0)
 804                 return ERR_PTR(m->err);
 805
 806         req = kmalloc(sizeof(struct p9_req), GFP_KERNEL);
 807         if (!req)
 808                 return ERR_PTR(-ENOMEM);
 809
 810         if (tc->id == P9_TVERSION)
 811                 n = P9_NOTAG;
 812         else
 813                 n = p9_mux_get_tag(m);
 814
 815         if (n < 0) {
 816                 kfree(req);
 817                 return ERR_PTR(-ENOMEM);
 818         }
 819
 820         p9_set_tag(tc, n);
 821
 822 #ifdef CONFIG_NET_9P_DEBUG
 823         if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
 824                 char buf[150];
 825
 826                 p9_printfcall(buf, sizeof(buf), tc, m->client->dotu);
 827                 printk(KERN_NOTICE "<<< %p %s\n", m, buf);
 828         }
 829 #endif
 830
 831         spin_lock_init(&req->lock);
 832         req->m = m;
 833         init_waitqueue_head(&req->wqueue);
 834         req->tag = n;
 835         req->tcall = tc;
 836         req->rcall = NULL;
 837         req->err = 0;
 838         req->cb = cb;
 839         req->cba = cba;
 840         req->flush = None;
 841
 842         spin_lock(&m->lock);
 843         list_add_tail(&req->req_list, &m->unsent_req_list);
 844         spin_unlock(&m->lock);
 845
 846         if (test_and_clear_bit(Wpending, &m->wsched))
 847                 n = POLLOUT;
 848         else
 849                 n = p9_fd_poll(m->client, NULL);
 850
 851         if (n & POLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
 852                 queue_work(p9_mux_wq, &m->wq);
 853
 854         return req;
 855 }
 856
 857 static void p9_mux_free_request(struct p9_conn *m, struct p9_req *req)
 858 {
 859         p9_mux_put_tag(m, req->tag);
 860         kfree(req);
 861 }
 862
 863 static void p9_mux_flush_cb(struct p9_req *freq, void *a)
 864 {
 865         int tag;
 866         struct p9_conn *m;
 867         struct p9_req *req, *rreq, *rptr;
 868
 869         m = a;
 870         P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m,
 871                 freq->tcall, freq->rcall, freq->err,
 872                 freq->tcall->params.tflush.oldtag);
 873
 874         spin_lock(&m->lock);
 875         tag = freq->tcall->params.tflush.oldtag;
 876         req = NULL;
 877         list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
 878                 if (rreq->tag == tag) {
 879                         req = rreq;
 880                         list_del(&req->req_list);
 881                         break;
 882                 }
 883         }
 884         spin_unlock(&m->lock);
 885
 886         if (req) {
 887                 spin_lock(&req->lock);
 888                 req->flush = Flushed;
 889                 spin_unlock(&req->lock);
 890
 891                 if (req->cb)
 892                         (*req->cb) (req, req->cba);
 893                 else
 894                         kfree(req->rcall);
 895         }
 896
 897         kfree(freq->tcall);
 898         kfree(freq->rcall);
 899         p9_mux_free_request(m, freq);
 900 }
 901
 902 static int
 903 p9_mux_flush_request(struct p9_conn *m, struct p9_req *req)
 904 {
 905         struct p9_fcall *fc;
 906         struct p9_req *rreq, *rptr;
 907
 908         P9_DPRINTK(P9_DEBUG_MUX, "mux %p req %p tag %d\n", m, req, req->tag);
 909
 910         /* if a response was received for a request, do nothing */
 911         spin_lock(&req->lock);
 912         if (req->rcall || req->err) {
 913                 spin_unlock(&req->lock);
 914                 P9_DPRINTK(P9_DEBUG_MUX,
 915                         "mux %p req %p response already received\n", m, req);
 916                 return 0;
 917         }
 918
 919         req->flush = Flushing;
 920         spin_unlock(&req->lock);
 921
 922         spin_lock(&m->lock);
 923         /* if the request is not sent yet, just remove it from the list */
 924         list_for_each_entry_safe(rreq, rptr, &m->unsent_req_list, req_list) {
 925                 if (rreq->tag == req->tag) {
 926                         P9_DPRINTK(P9_DEBUG_MUX,
 927                            "mux %p req %p request is not sent yet\n", m, req);
 928                         list_del(&rreq->req_list);
 929                         req->flush = Flushed;
 930                         spin_unlock(&m->lock);
 931                         if (req->cb)
 932                                 (*req->cb) (req, req->cba);
 933                         return 0;
 934                 }
 935         }
 936         spin_unlock(&m->lock);
 937
 938         clear_thread_flag(TIF_SIGPENDING);
 939         fc = p9_create_tflush(req->tag);
 940         p9_send_request(m, fc, p9_mux_flush_cb, m);
 941         return 1;
 942 }
 943
 944 static void p9_conn_rpc_cb(struct p9_req *req, void *a)
 945 {
 946         P9_DPRINTK(P9_DEBUG_MUX, "req %p arg %p\n", req, a);
 947
 948         if (req->flush != None && !req->err)
 949                 req->err = -ERESTARTSYS;
 950
 951         wake_up(&req->wqueue);
 952 }
 953
 954 /**
 955  * p9_fd_rpc- sends 9P request and waits until a response is available.
 956  *      The function can be interrupted.
 957  * @client: client instance
 958  * @tc: request to be sent
 959  * @rc: pointer where a pointer to the response is stored
 960  *
 961  */
 962
 963 int
 964 p9_fd_rpc(struct p9_client *client, struct p9_fcall *tc, struct p9_fcall **rc)
 965 {
 966         struct p9_trans_fd *p = client->trans;
 967         struct p9_conn *m = p->conn;
 968         int err, sigpending;
 969         unsigned long flags;
 970         struct p9_req *req;
 971
 972         if (rc)
 973                 *rc = NULL;
 974
 975         sigpending = 0;
 976         if (signal_pending(current)) {
 977                 sigpending = 1;
 978                 clear_thread_flag(TIF_SIGPENDING);
 979         }
 980
 981         req = p9_send_request(m, tc, p9_conn_rpc_cb, NULL);
 982         if (IS_ERR(req)) {
 983                 err = PTR_ERR(req);
 984                 P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);
 985                 return err;
 986         }
 987
 988         err = wait_event_interruptible(req->wqueue, req->rcall != NULL ||
 989                                                                 req->err < 0);
 990         if (req->err < 0)
 991                 err = req->err;
 992
 993         if (err == -ERESTARTSYS && client->status == Connected
 994                                                         && m->err == 0) {
 995                 if (p9_mux_flush_request(m, req)) {
 996                         /* wait until we get response of the flush message */
 997                         do {
 998                                 clear_thread_flag(TIF_SIGPENDING);
 999                                 err = wait_event_interruptible(req->wqueue,
1000                                         req->rcall || req->err);
1001                         } while (!req->rcall && !req->err &&
1002                                         err == -ERESTARTSYS &&
1003                                         client->status == Connected && !m->err);
1004
1005                         err = -ERESTARTSYS;
1006                 }
1007                 sigpending = 1;
1008         }
1009
1010         if (sigpending) {
1011                 spin_lock_irqsave(&current->sighand->siglock, flags);
1012                 recalc_sigpending();
1013                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
1014         }
1015
1016         if (rc)
1017                 *rc = req->rcall;
1018         else
1019                 kfree(req->rcall);
1020
1021         p9_mux_free_request(m, req);
1022         if (err > 0)
1023                 err = -EIO;
1024
1025         return err;
1026 }
1027
1028 /**
1029  * parse_options - parse mount options into session structure
1030  * @options: options string passed from mount
1031  * @opts: transport-specific structure to parse options into
1032  *
1033  * Returns 0 upon success, -ERRNO upon failure
1034  */
1035
1036 static int parse_opts(char *params, struct p9_fd_opts *opts)
1037 {
1038         char *p;
1039         substring_t args[MAX_OPT_ARGS];
1040         int option;
1041         char *options;
1042         int ret;
1043
1044         opts->port = P9_PORT;
1045         opts->rfd = ~0;
1046         opts->wfd = ~0;
1047
1048         if (!params)
1049                 return 0;
1050
1051         options = kstrdup(params, GFP_KERNEL);
1052         if (!options) {
1053                 P9_DPRINTK(P9_DEBUG_ERROR,
1054                                 "failed to allocate copy of option string\n");
1055                 return -ENOMEM;
1056         }
1057
1058         while ((p = strsep(&options, ",")) != NULL) {
1059                 int token;
1060                 int r;
1061                 if (!*p)
1062                         continue;
1063                 token = match_token(p, tokens, args);
1064                 r = match_int(&args[0], &option);
1065                 if (r < 0) {
1066                         P9_DPRINTK(P9_DEBUG_ERROR,
1067                          "integer field, but no integer?\n");
1068                         ret = r;
1069                         continue;
1070                 }
1071                 switch (token) {
1072                 case Opt_port:
1073                         opts->port = option;
1074                         break;
1075                 case Opt_rfdno:
1076                         opts->rfd = option;
1077                         break;
1078                 case Opt_wfdno:
1079                         opts->wfd = option;
1080                         break;
1081                 default:
1082                         continue;
1083                 }
1084         }
1085         kfree(options);
1086         return 0;
1087 }
1088
1089 static int p9_fd_open(struct p9_client *client, int rfd, int wfd)
1090 {
1091         struct p9_trans_fd *ts = kmalloc(sizeof(struct p9_trans_fd),
1092                                            GFP_KERNEL);
1093         if (!ts)
1094                 return -ENOMEM;
1095
1096         ts->rd = fget(rfd);
1097         ts->wr = fget(wfd);
1098         if (!ts->rd || !ts->wr) {
1099                 if (ts->rd)
1100                         fput(ts->rd);
1101                 if (ts->wr)
1102                         fput(ts->wr);
1103                 kfree(ts);
1104                 return -EIO;
1105         }
1106
1107         client->trans = ts;
1108         client->status = Connected;
1109
1110         return 0;
1111 }
1112
1113 static int p9_socket_open(struct p9_client *client, struct socket *csocket)
1114 {
1115         int fd, ret;
1116
1117         csocket->sk->sk_allocation = GFP_NOIO;
1118         fd = sock_map_fd(csocket, 0);
1119         if (fd < 0) {
1120                 P9_EPRINTK(KERN_ERR, "p9_socket_open: failed to map fd\n");
1121                 return fd;
1122         }
1123
1124         ret = p9_fd_open(client, fd, fd);
1125         if (ret < 0) {
1126                 P9_EPRINTK(KERN_ERR, "p9_socket_open: failed to open fd\n");
1127                 sockfd_put(csocket);
1128                 return ret;
1129         }
1130
1131         ((struct p9_trans_fd *)client->trans)->rd->f_flags |= O_NONBLOCK;
1132
1133         return 0;
1134 }
1135
1136 /**
1137  * p9_mux_destroy - cancels all pending requests and frees mux resources
1138  * @m: mux to destroy
1139  *
1140  */
1141
1142 static void p9_conn_destroy(struct p9_conn *m)
1143 {
1144         P9_DPRINTK(P9_DEBUG_MUX, "mux %p prev %p next %p\n", m,
1145                 m->mux_list.prev, m->mux_list.next);
1146
1147         p9_mux_poll_stop(m);
1148         cancel_work_sync(&m->rq);
1149         cancel_work_sync(&m->wq);
1150
1151         p9_conn_cancel(m, -ECONNRESET);
1152
1153         m->client = NULL;
1154         p9_idpool_destroy(m->tagpool);
1155         kfree(m);
1156 }
1157
1158 /**
1159  * p9_fd_close - shutdown file descriptor transport
1160  * @client: client instance
1161  *
1162  */
1163
1164 static void p9_fd_close(struct p9_client *client)
1165 {
1166         struct p9_trans_fd *ts;
1167
1168         if (!client)
1169                 return;
1170
1171         ts = client->trans;
1172         if (!ts)
1173                 return;
1174
1175         client->status = Disconnected;
1176
1177         p9_conn_destroy(ts->conn);
1178
1179         if (ts->rd)
1180                 fput(ts->rd);
1181         if (ts->wr)
1182                 fput(ts->wr);
1183
1184         kfree(ts);
1185 }
1186
1187 /*
1188  * stolen from NFS - maybe should be made a generic function?
1189  */
1190 static inline int valid_ipaddr4(const char *buf)
1191 {
1192         int rc, count, in[4];
1193
1194         rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
1195         if (rc != 4)
1196                 return -EINVAL;
1197         for (count = 0; count < 4; count++) {
1198                 if (in[count] > 255)
1199                         return -EINVAL;
1200         }
1201         return 0;
1202 }
1203
1204 static int
1205 p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args)
1206 {
1207         int err;
1208         struct socket *csocket;
1209         struct sockaddr_in sin_server;
1210         struct p9_fd_opts opts;
1211         struct p9_trans_fd *p = NULL; /* this gets allocated in p9_fd_open */
1212
1213         err = parse_opts(args, &opts);
1214         if (err < 0)
1215                 return err;
1216
1217         if (valid_ipaddr4(addr) < 0)
1218                 return -EINVAL;
1219
1220         csocket = NULL;
1221
1222         sin_server.sin_family = AF_INET;
1223         sin_server.sin_addr.s_addr = in_aton(addr);
1224         sin_server.sin_port = htons(opts.port);
1225         sock_create_kern(PF_INET, SOCK_STREAM, IPPROTO_TCP, &csocket);
1226
1227         if (!csocket) {
1228                 P9_EPRINTK(KERN_ERR, "p9_trans_tcp: problem creating socket\n");
1229                 err = -EIO;
1230                 goto error;
1231         }
1232
1233         err = csocket->ops->connect(csocket,
1234                                     (struct sockaddr *)&sin_server,
1235                                     sizeof(struct sockaddr_in), 0);
1236         if (err < 0) {
1237                 P9_EPRINTK(KERN_ERR,
1238                         "p9_trans_tcp: problem connecting socket to %s\n",
1239                         addr);
1240                 goto error;
1241         }
1242
1243         err = p9_socket_open(client, csocket);
1244         if (err < 0)
1245                 goto error;
1246
1247         p = (struct p9_trans_fd *) client->trans;
1248         p->conn = p9_conn_create(client);
1249         if (IS_ERR(p->conn)) {
1250                 err = PTR_ERR(p->conn);
1251                 p->conn = NULL;
1252                 goto error;
1253         }
1254
1255         return 0;
1256
1257 error:
1258         if (csocket)
1259                 sock_release(csocket);
1260
1261         kfree(p);
1262
1263         return err;
1264 }
1265
1266 static int
1267 p9_fd_create_unix(struct p9_client *client, const char *addr, char *args)
1268 {
1269         int err;
1270         struct socket *csocket;
1271         struct sockaddr_un sun_server;
1272         struct p9_trans_fd *p = NULL; /* this gets allocated in p9_fd_open */
1273
1274         csocket = NULL;
1275
1276         if (strlen(addr) > UNIX_PATH_MAX) {
1277                 P9_EPRINTK(KERN_ERR, "p9_trans_unix: address too long: %s\n",
1278                         addr);
1279                 err = -ENAMETOOLONG;
1280                 goto error;
1281         }
1282
1283         sun_server.sun_family = PF_UNIX;
1284         strcpy(sun_server.sun_path, addr);
1285         sock_create_kern(PF_UNIX, SOCK_STREAM, 0, &csocket);
1286         err = csocket->ops->connect(csocket, (struct sockaddr *)&sun_server,
1287                         sizeof(struct sockaddr_un) - 1, 0);
1288         if (err < 0) {
1289                 P9_EPRINTK(KERN_ERR,
1290                         "p9_trans_unix: problem connecting socket: %s: %d\n",
1291                         addr, err);
1292                 goto error;
1293         }
1294
1295         err = p9_socket_open(client, csocket);
1296         if (err < 0)
1297                 goto error;
1298
1299         p = (struct p9_trans_fd *) client->trans;
1300         p->conn = p9_conn_create(client);
1301         if (IS_ERR(p->conn)) {
1302                 err = PTR_ERR(p->conn);
1303                 p->conn = NULL;
1304                 goto error;
1305         }
1306
1307         return 0;
1308
1309 error:
1310         if (csocket)
1311                 sock_release(csocket);
1312
1313         kfree(p);
1314         return err;
1315 }
1316
1317 static int
1318 p9_fd_create(struct p9_client *client, const char *addr, char *args)
1319 {
1320         int err;
1321         struct p9_fd_opts opts;
1322         struct p9_trans_fd *p = NULL; /* this get allocated in p9_fd_open */
1323
1324         parse_opts(args, &opts);
1325
1326         if (opts.rfd == ~0 || opts.wfd == ~0) {
1327                 printk(KERN_ERR "v9fs: Insufficient options for proto=fd\n");
1328                 return -ENOPROTOOPT;
1329         }
1330
1331         err = p9_fd_open(client, opts.rfd, opts.wfd);
1332         if (err < 0)
1333                 goto error;
1334
1335         p = (struct p9_trans_fd *) client->trans;
1336         p->conn = p9_conn_create(client);
1337         if (IS_ERR(p->conn)) {
1338                 err = PTR_ERR(p->conn);
1339                 p->conn = NULL;
1340                 goto error;
1341         }
1342
1343         return 0;
1344
1345 error:
1346         kfree(p);
1347         return err;
1348 }
1349
1350 static struct p9_trans_module p9_tcp_trans = {
1351         .name = "tcp",
1352         .maxsize = MAX_SOCK_BUF,
1353         .def = 1,
1354         .create = p9_fd_create_tcp,
1355         .close = p9_fd_close,
1356         .rpc = p9_fd_rpc,
1357         .owner = THIS_MODULE,
1358 };
1359
1360 static struct p9_trans_module p9_unix_trans = {
1361         .name = "unix",
1362         .maxsize = MAX_SOCK_BUF,
1363         .def = 0,
1364         .create = p9_fd_create_unix,
1365         .close = p9_fd_close,
1366         .rpc = p9_fd_rpc,
1367         .owner = THIS_MODULE,
1368 };
1369
1370 static struct p9_trans_module p9_fd_trans = {
1371         .name = "fd",
1372         .maxsize = MAX_SOCK_BUF,
1373         .def = 0,
1374         .create = p9_fd_create,
1375         .close = p9_fd_close,
1376         .rpc = p9_fd_rpc,
1377         .owner = THIS_MODULE,
1378 };
1379
1380 /**
1381  * p9_poll_proc - poll worker thread
1382  * @a: thread state and arguments
1383  *
1384  * polls all v9fs transports for new events and queues the appropriate
1385  * work to the work queue
1386  *
1387  */
1388
1389 static int p9_poll_proc(void *a)
1390 {
1391         unsigned long flags;
1392
1393         P9_DPRINTK(P9_DEBUG_MUX, "start %p\n", current);
1394  repeat:
1395         spin_lock_irqsave(&p9_poll_lock, flags);
1396         while (!list_empty(&p9_poll_pending_list)) {
1397                 struct p9_conn *conn = list_first_entry(&p9_poll_pending_list,
1398                                                         struct p9_conn,
1399                                                         poll_pending_link);
1400                 list_del_init(&conn->poll_pending_link);
1401                 spin_unlock_irqrestore(&p9_poll_lock, flags);
1402
1403                 p9_poll_mux(conn);
1404
1405                 spin_lock_irqsave(&p9_poll_lock, flags);
1406         }
1407         spin_unlock_irqrestore(&p9_poll_lock, flags);
1408
1409         set_current_state(TASK_INTERRUPTIBLE);
1410         if (list_empty(&p9_poll_pending_list)) {
1411                 P9_DPRINTK(P9_DEBUG_MUX, "sleeping...\n");
1412                 schedule();
1413         }
1414         __set_current_state(TASK_RUNNING);
1415
1416         if (!kthread_should_stop())
1417                 goto repeat;
1418
1419         P9_DPRINTK(P9_DEBUG_MUX, "finish\n");
1420         return 0;
1421 }
1422
1423 int p9_trans_fd_init(void)
1424 {
1425         p9_mux_wq = create_workqueue("v9fs");
1426         if (!p9_mux_wq) {
1427                 printk(KERN_WARNING "v9fs: mux: creating workqueue failed\n");
1428                 return -ENOMEM;
1429         }
1430
1431         p9_poll_task = kthread_run(p9_poll_proc, NULL, "v9fs-poll");
1432         if (IS_ERR(p9_poll_task)) {
1433                 destroy_workqueue(p9_mux_wq);
1434                 printk(KERN_WARNING "v9fs: mux: creating poll task failed\n");
1435                 return PTR_ERR(p9_poll_task);
1436         }
1437
1438         v9fs_register_trans(&p9_tcp_trans);
1439         v9fs_register_trans(&p9_unix_trans);
1440         v9fs_register_trans(&p9_fd_trans);
1441
1442         return 0;
1443 }
1444
1445 void p9_trans_fd_exit(void)
1446 {
1447         kthread_stop(p9_poll_task);
1448         v9fs_unregister_trans(&p9_tcp_trans);
1449         v9fs_unregister_trans(&p9_unix_trans);
1450         v9fs_unregister_trans(&p9_fd_trans);
1451
1452         destroy_workqueue(p9_mux_wq);
1453 }