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 <linux/slab.h>
  42 #include <net/9p/9p.h>
  43 #include <net/9p/client.h>
  44 #include <net/9p/transport.h>
  45
  46 #include <linux/syscalls.h> /* killme */
  47
  48 #define P9_PORT 564
  49 #define MAX_SOCK_BUF (64*1024)
  50 #define MAXPOLLWADDR    2
  51
  52 /**
  53  * struct p9_fd_opts - per-transport options
  54  * @rfd: file descriptor for reading (trans=fd)
  55  * @wfd: file descriptor for writing (trans=fd)
  56  * @port: port to connect to (trans=tcp)
  57  *
  58  */
  59
  60 struct p9_fd_opts {
  61         int rfd;
  62         int wfd;
  63         u16 port;
  64 };
  65
  66 /**
  67  * struct p9_trans_fd - transport state
  68  * @rd: reference to file to read from
  69  * @wr: reference of file to write to
  70  * @conn: connection state reference
  71  *
  72  */
  73
  74 struct p9_trans_fd {
  75         struct file *rd;
  76         struct file *wr;
  77         struct p9_conn *conn;
  78 };
  79
  80 /*
  81   * Option Parsing (code inspired by NFS code)
  82   *  - a little lazy - parse all fd-transport options
  83   */
  84
  85 enum {
  86         /* Options that take integer arguments */
  87         Opt_port, Opt_rfdno, Opt_wfdno, Opt_err,
  88 };
  89
  90 static const match_table_t tokens = {
  91         {Opt_port, "port=%u"},
  92         {Opt_rfdno, "rfdno=%u"},
  93         {Opt_wfdno, "wfdno=%u"},
  94         {Opt_err, NULL},
  95 };
  96
  97 enum {
  98         Rworksched = 1,         /* read work scheduled or running */
  99         Rpending = 2,           /* can read */
 100         Wworksched = 4,         /* write work scheduled or running */
 101         Wpending = 8,           /* can write */
 102 };
 103
 104 struct p9_poll_wait {
 105         struct p9_conn *conn;
 106         wait_queue_t wait;
 107         wait_queue_head_t *wait_addr;
 108 };
 109
 110 /**
 111  * struct p9_conn - fd mux connection state information
 112  * @mux_list: list link for mux to manage multiple connections (?)
 113  * @client: reference to client instance for this connection
 114  * @err: error state
 115  * @req_list: accounting for requests which have been sent
 116  * @unsent_req_list: accounting for requests that haven't been sent
 117  * @req: current request being processed (if any)
 118  * @tmp_buf: temporary buffer to read in header
 119  * @rsize: amount to read for current frame
 120  * @rpos: read position in current frame
 121  * @rbuf: current read buffer
 122  * @wpos: write position for current frame
 123  * @wsize: amount of data to write for current frame
 124  * @wbuf: current write buffer
 125  * @poll_pending_link: pending links to be polled per conn
 126  * @poll_wait: array of wait_q's for various worker threads
 127  * @pt: poll state
 128  * @rq: current read work
 129  * @wq: current write work
 130  * @wsched: ????
 131  *
 132  */
 133
 134 struct p9_conn {
 135         struct list_head mux_list;
 136         struct p9_client *client;
 137         int err;
 138         struct list_head req_list;
 139         struct list_head unsent_req_list;
 140         struct p9_req_t *req;
 141         char tmp_buf[7];
 142         int rsize;
 143         int rpos;
 144         char *rbuf;
 145         int wpos;
 146         int wsize;
 147         char *wbuf;
 148         struct list_head poll_pending_link;
 149         struct p9_poll_wait poll_wait[MAXPOLLWADDR];
 150         poll_table pt;
 151         struct work_struct rq;
 152         struct work_struct wq;
 153         unsigned long wsched;
 154 };
 155
 156 static DEFINE_SPINLOCK(p9_poll_lock);
 157 static LIST_HEAD(p9_poll_pending_list);
 158 static struct workqueue_struct *p9_mux_wq;
 159 static struct task_struct *p9_poll_task;
 160
 161 static void p9_mux_poll_stop(struct p9_conn *m)
 162 {
 163         unsigned long flags;
 164         int i;
 165
 166         for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
 167                 struct p9_poll_wait *pwait = &m->poll_wait[i];
 168
 169                 if (pwait->wait_addr) {
 170                         remove_wait_queue(pwait->wait_addr, &pwait->wait);
 171                         pwait->wait_addr = NULL;
 172                 }
 173         }
 174
 175         spin_lock_irqsave(&p9_poll_lock, flags);
 176         list_del_init(&m->poll_pending_link);
 177         spin_unlock_irqrestore(&p9_poll_lock, flags);
 178 }
 179
 180 /**
 181  * p9_conn_cancel - cancel all pending requests with error
 182  * @m: mux data
 183  * @err: error code
 184  *
 185  */
 186
 187 static void p9_conn_cancel(struct p9_conn *m, int err)
 188 {
 189         struct p9_req_t *req, *rtmp;
 190         unsigned long flags;
 191         LIST_HEAD(cancel_list);
 192
 193         P9_DPRINTK(P9_DEBUG_ERROR, "mux %p err %d\n", m, err);
 194
 195         spin_lock_irqsave(&m->client->lock, flags);
 196
 197         if (m->err) {
 198                 spin_unlock_irqrestore(&m->client->lock, flags);
 199                 return;
 200         }
 201
 202         m->err = err;
 203
 204         list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
 205                 req->status = REQ_STATUS_ERROR;
 206                 if (!req->t_err)
 207                         req->t_err = err;
 208                 list_move(&req->req_list, &cancel_list);
 209         }
 210         list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) {
 211                 req->status = REQ_STATUS_ERROR;
 212                 if (!req->t_err)
 213                         req->t_err = err;
 214                 list_move(&req->req_list, &cancel_list);
 215         }
 216         spin_unlock_irqrestore(&m->client->lock, flags);
 217
 218         list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
 219                 P9_DPRINTK(P9_DEBUG_ERROR, "call back req %p\n", req);
 220                 list_del(&req->req_list);
 221                 p9_client_cb(m->client, req);
 222         }
 223 }
 224
 225 static int
 226 p9_fd_poll(struct p9_client *client, struct poll_table_struct *pt)
 227 {
 228         int ret, n;
 229         struct p9_trans_fd *ts = NULL;
 230
 231         if (client && client->status == Connected)
 232                 ts = client->trans;
 233
 234         if (!ts)
 235                 return -EREMOTEIO;
 236
 237         if (!ts->rd->f_op || !ts->rd->f_op->poll)
 238                 return -EIO;
 239
 240         if (!ts->wr->f_op || !ts->wr->f_op->poll)
 241                 return -EIO;
 242
 243         ret = ts->rd->f_op->poll(ts->rd, pt);
 244         if (ret < 0)
 245                 return ret;
 246
 247         if (ts->rd != ts->wr) {
 248                 n = ts->wr->f_op->poll(ts->wr, pt);
 249                 if (n < 0)
 250                         return n;
 251                 ret = (ret & ~POLLOUT) | (n & ~POLLIN);
 252         }
 253
 254         return ret;
 255 }
 256
 257 /**
 258  * p9_fd_read- read from a fd
 259  * @client: client instance
 260  * @v: buffer to receive data into
 261  * @len: size of receive buffer
 262  *
 263  */
 264
 265 static int p9_fd_read(struct p9_client *client, void *v, int len)
 266 {
 267         int ret;
 268         struct p9_trans_fd *ts = NULL;
 269
 270         if (client && client->status != Disconnected)
 271                 ts = client->trans;
 272
 273         if (!ts)
 274                 return -EREMOTEIO;
 275
 276         if (!(ts->rd->f_flags & O_NONBLOCK))
 277                 P9_DPRINTK(P9_DEBUG_ERROR, "blocking read ...\n");
 278
 279         ret = kernel_read(ts->rd, ts->rd->f_pos, v, len);
 280         if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
 281                 client->status = Disconnected;
 282         return ret;
 283 }
 284
 285 /**
 286  * p9_read_work - called when there is some data to be read from a transport
 287  * @work: container of work to be done
 288  *
 289  */
 290
 291 static void p9_read_work(struct work_struct *work)
 292 {
 293         int n, err;
 294         struct p9_conn *m;
 295
 296         m = container_of(work, struct p9_conn, rq);
 297
 298         if (m->err < 0)
 299                 return;
 300
 301         P9_DPRINTK(P9_DEBUG_TRANS, "start mux %p pos %d\n", m, m->rpos);
 302
 303         if (!m->rbuf) {
 304                 m->rbuf = m->tmp_buf;
 305                 m->rpos = 0;
 306                 m->rsize = 7; /* start by reading header */
 307         }
 308
 309         clear_bit(Rpending, &m->wsched);
 310         P9_DPRINTK(P9_DEBUG_TRANS, "read mux %p pos %d size: %d = %d\n", m,
 311                                         m->rpos, m->rsize, m->rsize-m->rpos);
 312         err = p9_fd_read(m->client, m->rbuf + m->rpos,
 313                                                 m->rsize - m->rpos);
 314         P9_DPRINTK(P9_DEBUG_TRANS, "mux %p got %d bytes\n", m, err);
 315         if (err == -EAGAIN) {
 316                 clear_bit(Rworksched, &m->wsched);
 317                 return;
 318         }
 319
 320         if (err <= 0)
 321                 goto error;
 322
 323         m->rpos += err;
 324
 325         if ((!m->req) && (m->rpos == m->rsize)) { /* header read in */
 326                 u16 tag;
 327                 P9_DPRINTK(P9_DEBUG_TRANS, "got new header\n");
 328
 329                 n = le32_to_cpu(*(__le32 *) m->rbuf); /* read packet size */
 330                 if (n >= m->client->msize) {
 331                         P9_DPRINTK(P9_DEBUG_ERROR,
 332                                 "requested packet size too big: %d\n", n);
 333                         err = -EIO;
 334                         goto error;
 335                 }
 336
 337                 tag = le16_to_cpu(*(__le16 *) (m->rbuf+5)); /* read tag */
 338                 P9_DPRINTK(P9_DEBUG_TRANS,
 339                         "mux %p pkt: size: %d bytes tag: %d\n", m, n, tag);
 340
 341                 m->req = p9_tag_lookup(m->client, tag);
 342                 if (!m->req || (m->req->status != REQ_STATUS_SENT &&
 343                                         m->req->status != REQ_STATUS_FLSH)) {
 344                         P9_DPRINTK(P9_DEBUG_ERROR, "Unexpected packet tag %d\n",
 345                                                                  tag);
 346                         err = -EIO;
 347                         goto error;
 348                 }
 349
 350                 if (m->req->rc == NULL) {
 351                         m->req->rc = kmalloc(sizeof(struct p9_fcall) +
 352                                                 m->client->msize, GFP_KERNEL);
 353                         if (!m->req->rc) {
 354                                 m->req = NULL;
 355                                 err = -ENOMEM;
 356                                 goto error;
 357                         }
 358                 }
 359                 m->rbuf = (char *)m->req->rc + sizeof(struct p9_fcall);
 360                 memcpy(m->rbuf, m->tmp_buf, m->rsize);
 361                 m->rsize = n;
 362         }
 363
 364         /* not an else because some packets (like clunk) have no payload */
 365         if ((m->req) && (m->rpos == m->rsize)) { /* packet is read in */
 366                 P9_DPRINTK(P9_DEBUG_TRANS, "got new packet\n");
 367                 spin_lock(&m->client->lock);
 368                 if (m->req->status != REQ_STATUS_ERROR)
 369                         m->req->status = REQ_STATUS_RCVD;
 370                 list_del(&m->req->req_list);
 371                 spin_unlock(&m->client->lock);
 372                 p9_client_cb(m->client, m->req);
 373                 m->rbuf = NULL;
 374                 m->rpos = 0;
 375                 m->rsize = 0;
 376                 m->req = NULL;
 377         }
 378
 379         if (!list_empty(&m->req_list)) {
 380                 if (test_and_clear_bit(Rpending, &m->wsched))
 381                         n = POLLIN;
 382                 else
 383                         n = p9_fd_poll(m->client, NULL);
 384
 385                 if (n & POLLIN) {
 386                         P9_DPRINTK(P9_DEBUG_TRANS, "sched read work %p\n", m);
 387                         queue_work(p9_mux_wq, &m->rq);
 388                 } else
 389                         clear_bit(Rworksched, &m->wsched);
 390         } else
 391                 clear_bit(Rworksched, &m->wsched);
 392
 393         return;
 394 error:
 395         p9_conn_cancel(m, err);
 396         clear_bit(Rworksched, &m->wsched);
 397 }
 398
 399 /**
 400  * p9_fd_write - write to a socket
 401  * @client: client instance
 402  * @v: buffer to send data from
 403  * @len: size of send buffer
 404  *
 405  */
 406
 407 static int p9_fd_write(struct p9_client *client, void *v, int len)
 408 {
 409         int ret;
 410         mm_segment_t oldfs;
 411         struct p9_trans_fd *ts = NULL;
 412
 413         if (client && client->status != Disconnected)
 414                 ts = client->trans;
 415
 416         if (!ts)
 417                 return -EREMOTEIO;
 418
 419         if (!(ts->wr->f_flags & O_NONBLOCK))
 420                 P9_DPRINTK(P9_DEBUG_ERROR, "blocking write ...\n");
 421
 422         oldfs = get_fs();
 423         set_fs(get_ds());
 424         /* The cast to a user pointer is valid due to the set_fs() */
 425         ret = vfs_write(ts->wr, (__force void __user *)v, len, &ts->wr->f_pos);
 426         set_fs(oldfs);
 427
 428         if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
 429                 client->status = Disconnected;
 430         return ret;
 431 }
 432
 433 /**
 434  * p9_write_work - called when a transport can send some data
 435  * @work: container for work to be done
 436  *
 437  */
 438
 439 static void p9_write_work(struct work_struct *work)
 440 {
 441         int n, err;
 442         struct p9_conn *m;
 443         struct p9_req_t *req;
 444
 445         m = container_of(work, struct p9_conn, wq);
 446
 447         if (m->err < 0) {
 448                 clear_bit(Wworksched, &m->wsched);
 449                 return;
 450         }
 451
 452         if (!m->wsize) {
 453                 if (list_empty(&m->unsent_req_list)) {
 454                         clear_bit(Wworksched, &m->wsched);
 455                         return;
 456                 }
 457
 458                 spin_lock(&m->client->lock);
 459                 req = list_entry(m->unsent_req_list.next, struct p9_req_t,
 460                                req_list);
 461                 req->status = REQ_STATUS_SENT;
 462                 P9_DPRINTK(P9_DEBUG_TRANS, "move req %p\n", req);
 463                 list_move_tail(&req->req_list, &m->req_list);
 464
 465                 m->wbuf = req->tc->sdata;
 466                 m->wsize = req->tc->size;
 467                 m->wpos = 0;
 468                 spin_unlock(&m->client->lock);
 469         }
 470
 471         P9_DPRINTK(P9_DEBUG_TRANS, "mux %p pos %d size %d\n", m, m->wpos,
 472                                                                 m->wsize);
 473         clear_bit(Wpending, &m->wsched);
 474         err = p9_fd_write(m->client, m->wbuf + m->wpos, m->wsize - m->wpos);
 475         P9_DPRINTK(P9_DEBUG_TRANS, "mux %p sent %d bytes\n", m, err);
 476         if (err == -EAGAIN) {
 477                 clear_bit(Wworksched, &m->wsched);
 478                 return;
 479         }
 480
 481         if (err < 0)
 482                 goto error;
 483         else if (err == 0) {
 484                 err = -EREMOTEIO;
 485                 goto error;
 486         }
 487
 488         m->wpos += err;
 489         if (m->wpos == m->wsize)
 490                 m->wpos = m->wsize = 0;
 491
 492         if (m->wsize == 0 && !list_empty(&m->unsent_req_list)) {
 493                 if (test_and_clear_bit(Wpending, &m->wsched))
 494                         n = POLLOUT;
 495                 else
 496                         n = p9_fd_poll(m->client, NULL);
 497
 498                 if (n & POLLOUT) {
 499                         P9_DPRINTK(P9_DEBUG_TRANS, "sched write work %p\n", m);
 500                         queue_work(p9_mux_wq, &m->wq);
 501                 } else
 502                         clear_bit(Wworksched, &m->wsched);
 503         } else
 504                 clear_bit(Wworksched, &m->wsched);
 505
 506         return;
 507
 508 error:
 509         p9_conn_cancel(m, err);
 510         clear_bit(Wworksched, &m->wsched);
 511 }
 512
 513 static int p9_pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
 514 {
 515         struct p9_poll_wait *pwait =
 516                 container_of(wait, struct p9_poll_wait, wait);
 517         struct p9_conn *m = pwait->conn;
 518         unsigned long flags;
 519         DECLARE_WAITQUEUE(dummy_wait, p9_poll_task);
 520
 521         spin_lock_irqsave(&p9_poll_lock, flags);
 522         if (list_empty(&m->poll_pending_link))
 523                 list_add_tail(&m->poll_pending_link, &p9_poll_pending_list);
 524         spin_unlock_irqrestore(&p9_poll_lock, flags);
 525
 526         /* perform the default wake up operation */
 527         return default_wake_function(&dummy_wait, mode, sync, key);
 528 }
 529
 530 /**
 531  * p9_pollwait - add poll task to the wait queue
 532  * @filp: file pointer being polled
 533  * @wait_address: wait_q to block on
 534  * @p: poll state
 535  *
 536  * called by files poll operation to add v9fs-poll task to files wait queue
 537  */
 538
 539 static void
 540 p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p)
 541 {
 542         struct p9_conn *m = container_of(p, struct p9_conn, pt);
 543         struct p9_poll_wait *pwait = NULL;
 544         int i;
 545
 546         for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
 547                 if (m->poll_wait[i].wait_addr == NULL) {
 548                         pwait = &m->poll_wait[i];
 549                         break;
 550                 }
 551         }
 552
 553         if (!pwait) {
 554                 P9_DPRINTK(P9_DEBUG_ERROR, "not enough wait_address slots\n");
 555                 return;
 556         }
 557
 558         pwait->conn = m;
 559         pwait->wait_addr = wait_address;
 560         init_waitqueue_func_entry(&pwait->wait, p9_pollwake);
 561         add_wait_queue(wait_address, &pwait->wait);
 562 }
 563
 564 /**
 565  * p9_conn_create - allocate and initialize the per-session mux data
 566  * @client: client instance
 567  *
 568  * Note: Creates the polling task if this is the first session.
 569  */
 570
 571 static struct p9_conn *p9_conn_create(struct p9_client *client)
 572 {
 573         int n;
 574         struct p9_conn *m;
 575
 576         P9_DPRINTK(P9_DEBUG_TRANS, "client %p msize %d\n", client,
 577                                                                 client->msize);
 578         m = kzalloc(sizeof(struct p9_conn), GFP_KERNEL);
 579         if (!m)
 580                 return ERR_PTR(-ENOMEM);
 581
 582         INIT_LIST_HEAD(&m->mux_list);
 583         m->client = client;
 584
 585         INIT_LIST_HEAD(&m->req_list);
 586         INIT_LIST_HEAD(&m->unsent_req_list);
 587         INIT_WORK(&m->rq, p9_read_work);
 588         INIT_WORK(&m->wq, p9_write_work);
 589         INIT_LIST_HEAD(&m->poll_pending_link);
 590         init_poll_funcptr(&m->pt, p9_pollwait);
 591
 592         n = p9_fd_poll(client, &m->pt);
 593         if (n & POLLIN) {
 594                 P9_DPRINTK(P9_DEBUG_TRANS, "mux %p can read\n", m);
 595                 set_bit(Rpending, &m->wsched);
 596         }
 597
 598         if (n & POLLOUT) {
 599                 P9_DPRINTK(P9_DEBUG_TRANS, "mux %p can write\n", m);
 600                 set_bit(Wpending, &m->wsched);
 601         }
 602
 603         return m;
 604 }
 605
 606 /**
 607  * p9_poll_mux - polls a mux and schedules read or write works if necessary
 608  * @m: connection to poll
 609  *
 610  */
 611
 612 static void p9_poll_mux(struct p9_conn *m)
 613 {
 614         int n;
 615
 616         if (m->err < 0)
 617                 return;
 618
 619         n = p9_fd_poll(m->client, NULL);
 620         if (n < 0 || n & (POLLERR | POLLHUP | POLLNVAL)) {
 621                 P9_DPRINTK(P9_DEBUG_TRANS, "error mux %p err %d\n", m, n);
 622                 if (n >= 0)
 623                         n = -ECONNRESET;
 624                 p9_conn_cancel(m, n);
 625         }
 626
 627         if (n & POLLIN) {
 628                 set_bit(Rpending, &m->wsched);
 629                 P9_DPRINTK(P9_DEBUG_TRANS, "mux %p can read\n", m);
 630                 if (!test_and_set_bit(Rworksched, &m->wsched)) {
 631                         P9_DPRINTK(P9_DEBUG_TRANS, "sched read work %p\n", m);
 632                         queue_work(p9_mux_wq, &m->rq);
 633                 }
 634         }
 635
 636         if (n & POLLOUT) {
 637                 set_bit(Wpending, &m->wsched);
 638                 P9_DPRINTK(P9_DEBUG_TRANS, "mux %p can write\n", m);
 639                 if ((m->wsize || !list_empty(&m->unsent_req_list)) &&
 640                     !test_and_set_bit(Wworksched, &m->wsched)) {
 641                         P9_DPRINTK(P9_DEBUG_TRANS, "sched write work %p\n", m);
 642                         queue_work(p9_mux_wq, &m->wq);
 643                 }
 644         }
 645 }
 646
 647 /**
 648  * p9_fd_request - send 9P request
 649  * The function can sleep until the request is scheduled for sending.
 650  * The function can be interrupted. Return from the function is not
 651  * a guarantee that the request is sent successfully.
 652  *
 653  * @client: client instance
 654  * @req: request to be sent
 655  *
 656  */
 657
 658 static int p9_fd_request(struct p9_client *client, struct p9_req_t *req)
 659 {
 660         int n;
 661         struct p9_trans_fd *ts = client->trans;
 662         struct p9_conn *m = ts->conn;
 663
 664         P9_DPRINTK(P9_DEBUG_TRANS, "mux %p task %p tcall %p id %d\n", m,
 665                                                 current, req->tc, req->tc->id);
 666         if (m->err < 0)
 667                 return m->err;
 668
 669         spin_lock(&client->lock);
 670         req->status = REQ_STATUS_UNSENT;
 671         list_add_tail(&req->req_list, &m->unsent_req_list);
 672         spin_unlock(&client->lock);
 673
 674         if (test_and_clear_bit(Wpending, &m->wsched))
 675                 n = POLLOUT;
 676         else
 677                 n = p9_fd_poll(m->client, NULL);
 678
 679         if (n & POLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
 680                 queue_work(p9_mux_wq, &m->wq);
 681
 682         return 0;
 683 }
 684
 685 static int p9_fd_cancel(struct p9_client *client, struct p9_req_t *req)
 686 {
 687         int ret = 1;
 688
 689         P9_DPRINTK(P9_DEBUG_TRANS, "client %p req %p\n", client, req);
 690
 691         spin_lock(&client->lock);
 692
 693         if (req->status == REQ_STATUS_UNSENT) {
 694                 list_del(&req->req_list);
 695                 req->status = REQ_STATUS_FLSHD;
 696                 ret = 0;
 697         } else if (req->status == REQ_STATUS_SENT)
 698                 req->status = REQ_STATUS_FLSH;
 699
 700         spin_unlock(&client->lock);
 701
 702         return ret;
 703 }
 704
 705 /**
 706  * parse_opts - parse mount options into p9_fd_opts structure
 707  * @params: options string passed from mount
 708  * @opts: fd transport-specific structure to parse options into
 709  *
 710  * Returns 0 upon success, -ERRNO upon failure
 711  */
 712
 713 static int parse_opts(char *params, struct p9_fd_opts *opts)
 714 {
 715         char *p;
 716         substring_t args[MAX_OPT_ARGS];
 717         int option;
 718         char *options, *tmp_options;
 719         int ret;
 720
 721         opts->port = P9_PORT;
 722         opts->rfd = ~0;
 723         opts->wfd = ~0;
 724
 725         if (!params)
 726                 return 0;
 727
 728         tmp_options = kstrdup(params, GFP_KERNEL);
 729         if (!tmp_options) {
 730                 P9_DPRINTK(P9_DEBUG_ERROR,
 731                                 "failed to allocate copy of option string\n");
 732                 return -ENOMEM;
 733         }
 734         options = tmp_options;
 735
 736         while ((p = strsep(&options, ",")) != NULL) {
 737                 int token;
 738                 int r;
 739                 if (!*p)
 740                         continue;
 741                 token = match_token(p, tokens, args);
 742                 if (token != Opt_err) {
 743                         r = match_int(&args[0], &option);
 744                         if (r < 0) {
 745                                 P9_DPRINTK(P9_DEBUG_ERROR,
 746                                 "integer field, but no integer?\n");
 747                                 ret = r;
 748                                 continue;
 749                         }
 750                 }
 751                 switch (token) {
 752                 case Opt_port:
 753                         opts->port = option;
 754                         break;
 755                 case Opt_rfdno:
 756                         opts->rfd = option;
 757                         break;
 758                 case Opt_wfdno:
 759                         opts->wfd = option;
 760                         break;
 761                 default:
 762                         continue;
 763                 }
 764         }
 765
 766         kfree(tmp_options);
 767         return 0;
 768 }
 769
 770 static int p9_fd_open(struct p9_client *client, int rfd, int wfd)
 771 {
 772         struct p9_trans_fd *ts = kmalloc(sizeof(struct p9_trans_fd),
 773                                            GFP_KERNEL);
 774         if (!ts)
 775                 return -ENOMEM;
 776
 777         ts->rd = fget(rfd);
 778         ts->wr = fget(wfd);
 779         if (!ts->rd || !ts->wr) {
 780                 if (ts->rd)
 781                         fput(ts->rd);
 782                 if (ts->wr)
 783                         fput(ts->wr);
 784                 kfree(ts);
 785                 return -EIO;
 786         }
 787
 788         client->trans = ts;
 789         client->status = Connected;
 790
 791         return 0;
 792 }
 793
 794 static int p9_socket_open(struct p9_client *client, struct socket *csocket)
 795 {
 796         struct p9_trans_fd *p;
 797         int ret, fd;
 798
 799         p = kmalloc(sizeof(struct p9_trans_fd), GFP_KERNEL);
 800         if (!p)
 801                 return -ENOMEM;
 802
 803         csocket->sk->sk_allocation = GFP_NOIO;
 804         fd = sock_map_fd(csocket, 0);
 805         if (fd < 0) {
 806                 P9_EPRINTK(KERN_ERR, "p9_socket_open: failed to map fd\n");
 807                 sock_release(csocket);
 808                 kfree(p);
 809                 return fd;
 810         }
 811
 812         get_file(csocket->file);
 813         get_file(csocket->file);
 814         p->wr = p->rd = csocket->file;
 815         client->trans = p;
 816         client->status = Connected;
 817
 818         sys_close(fd);  /* still racy */
 819
 820         p->rd->f_flags |= O_NONBLOCK;
 821
 822         p->conn = p9_conn_create(client);
 823         if (IS_ERR(p->conn)) {
 824                 ret = PTR_ERR(p->conn);
 825                 p->conn = NULL;
 826                 kfree(p);
 827                 sockfd_put(csocket);
 828                 sockfd_put(csocket);
 829                 return ret;
 830         }
 831         return 0;
 832 }
 833
 834 /**
 835  * p9_mux_destroy - cancels all pending requests and frees mux resources
 836  * @m: mux to destroy
 837  *
 838  */
 839
 840 static void p9_conn_destroy(struct p9_conn *m)
 841 {
 842         P9_DPRINTK(P9_DEBUG_TRANS, "mux %p prev %p next %p\n", m,
 843                 m->mux_list.prev, m->mux_list.next);
 844
 845         p9_mux_poll_stop(m);
 846         cancel_work_sync(&m->rq);
 847         cancel_work_sync(&m->wq);
 848
 849         p9_conn_cancel(m, -ECONNRESET);
 850
 851         m->client = NULL;
 852         kfree(m);
 853 }
 854
 855 /**
 856  * p9_fd_close - shutdown file descriptor transport
 857  * @client: client instance
 858  *
 859  */
 860
 861 static void p9_fd_close(struct p9_client *client)
 862 {
 863         struct p9_trans_fd *ts;
 864
 865         if (!client)
 866                 return;
 867
 868         ts = client->trans;
 869         if (!ts)
 870                 return;
 871
 872         client->status = Disconnected;
 873
 874         p9_conn_destroy(ts->conn);
 875
 876         if (ts->rd)
 877                 fput(ts->rd);
 878         if (ts->wr)
 879                 fput(ts->wr);
 880
 881         kfree(ts);
 882 }
 883
 884 /*
 885  * stolen from NFS - maybe should be made a generic function?
 886  */
 887 static inline int valid_ipaddr4(const char *buf)
 888 {
 889         int rc, count, in[4];
 890
 891         rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
 892         if (rc != 4)
 893                 return -EINVAL;
 894         for (count = 0; count < 4; count++) {
 895                 if (in[count] > 255)
 896                         return -EINVAL;
 897         }
 898         return 0;
 899 }
 900
 901 static int
 902 p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args)
 903 {
 904         int err;
 905         struct socket *csocket;
 906         struct sockaddr_in sin_server;
 907         struct p9_fd_opts opts;
 908
 909         err = parse_opts(args, &opts);
 910         if (err < 0)
 911                 return err;
 912
 913         if (valid_ipaddr4(addr) < 0)
 914                 return -EINVAL;
 915
 916         csocket = NULL;
 917
 918         sin_server.sin_family = AF_INET;
 919         sin_server.sin_addr.s_addr = in_aton(addr);
 920         sin_server.sin_port = htons(opts.port);
 921         err = sock_create_kern(PF_INET, SOCK_STREAM, IPPROTO_TCP, &csocket);
 922
 923         if (err) {
 924                 P9_EPRINTK(KERN_ERR, "p9_trans_tcp: problem creating socket\n");
 925                 return err;
 926         }
 927
 928         err = csocket->ops->connect(csocket,
 929                                     (struct sockaddr *)&sin_server,
 930                                     sizeof(struct sockaddr_in), 0);
 931         if (err < 0) {
 932                 P9_EPRINTK(KERN_ERR,
 933                         "p9_trans_tcp: problem connecting socket to %s\n",
 934                         addr);
 935                 sock_release(csocket);
 936                 return err;
 937         }
 938
 939         return p9_socket_open(client, csocket);
 940 }
 941
 942 static int
 943 p9_fd_create_unix(struct p9_client *client, const char *addr, char *args)
 944 {
 945         int err;
 946         struct socket *csocket;
 947         struct sockaddr_un sun_server;
 948
 949         csocket = NULL;
 950
 951         if (strlen(addr) >= UNIX_PATH_MAX) {
 952                 P9_EPRINTK(KERN_ERR, "p9_trans_unix: address too long: %s\n",
 953                         addr);
 954                 return -ENAMETOOLONG;
 955         }
 956
 957         sun_server.sun_family = PF_UNIX;
 958         strcpy(sun_server.sun_path, addr);
 959         err = sock_create_kern(PF_UNIX, SOCK_STREAM, 0, &csocket);
 960         if (err < 0) {
 961                 P9_EPRINTK(KERN_ERR, "p9_trans_unix: problem creating socket\n");
 962                 return err;
 963         }
 964         err = csocket->ops->connect(csocket, (struct sockaddr *)&sun_server,
 965                         sizeof(struct sockaddr_un) - 1, 0);
 966         if (err < 0) {
 967                 P9_EPRINTK(KERN_ERR,
 968                         "p9_trans_unix: problem connecting socket: %s: %d\n",
 969                         addr, err);
 970                 sock_release(csocket);
 971                 return err;
 972         }
 973
 974         return p9_socket_open(client, csocket);
 975 }
 976
 977 static int
 978 p9_fd_create(struct p9_client *client, const char *addr, char *args)
 979 {
 980         int err;
 981         struct p9_fd_opts opts;
 982         struct p9_trans_fd *p;
 983
 984         parse_opts(args, &opts);
 985
 986         if (opts.rfd == ~0 || opts.wfd == ~0) {
 987                 printk(KERN_ERR "v9fs: Insufficient options for proto=fd\n");
 988                 return -ENOPROTOOPT;
 989         }
 990
 991         err = p9_fd_open(client, opts.rfd, opts.wfd);
 992         if (err < 0)
 993                 return err;
 994
 995         p = (struct p9_trans_fd *) client->trans;
 996         p->conn = p9_conn_create(client);
 997         if (IS_ERR(p->conn)) {
 998                 err = PTR_ERR(p->conn);
 999                 p->conn = NULL;
1000                 fput(p->rd);
1001                 fput(p->wr);
1002                 return err;
1003         }
1004
1005         return 0;
1006 }
1007
1008 static struct p9_trans_module p9_tcp_trans = {
1009         .name = "tcp",
1010         .maxsize = MAX_SOCK_BUF,
1011         .def = 1,
1012         .create = p9_fd_create_tcp,
1013         .close = p9_fd_close,
1014         .request = p9_fd_request,
1015         .cancel = p9_fd_cancel,
1016         .owner = THIS_MODULE,
1017 };
1018
1019 static struct p9_trans_module p9_unix_trans = {
1020         .name = "unix",
1021         .maxsize = MAX_SOCK_BUF,
1022         .def = 0,
1023         .create = p9_fd_create_unix,
1024         .close = p9_fd_close,
1025         .request = p9_fd_request,
1026         .cancel = p9_fd_cancel,
1027         .owner = THIS_MODULE,
1028 };
1029
1030 static struct p9_trans_module p9_fd_trans = {
1031         .name = "fd",
1032         .maxsize = MAX_SOCK_BUF,
1033         .def = 0,
1034         .create = p9_fd_create,
1035         .close = p9_fd_close,
1036         .request = p9_fd_request,
1037         .cancel = p9_fd_cancel,
1038         .owner = THIS_MODULE,
1039 };
1040
1041 /**
1042  * p9_poll_proc - poll worker thread
1043  * @a: thread state and arguments
1044  *
1045  * polls all v9fs transports for new events and queues the appropriate
1046  * work to the work queue
1047  *
1048  */
1049
1050 static int p9_poll_proc(void *a)
1051 {
1052         unsigned long flags;
1053
1054         P9_DPRINTK(P9_DEBUG_TRANS, "start %p\n", current);
1055  repeat:
1056         spin_lock_irqsave(&p9_poll_lock, flags);
1057         while (!list_empty(&p9_poll_pending_list)) {
1058                 struct p9_conn *conn = list_first_entry(&p9_poll_pending_list,
1059                                                         struct p9_conn,
1060                                                         poll_pending_link);
1061                 list_del_init(&conn->poll_pending_link);
1062                 spin_unlock_irqrestore(&p9_poll_lock, flags);
1063
1064                 p9_poll_mux(conn);
1065
1066                 spin_lock_irqsave(&p9_poll_lock, flags);
1067         }
1068         spin_unlock_irqrestore(&p9_poll_lock, flags);
1069
1070         set_current_state(TASK_INTERRUPTIBLE);
1071         if (list_empty(&p9_poll_pending_list)) {
1072                 P9_DPRINTK(P9_DEBUG_TRANS, "sleeping...\n");
1073                 schedule();
1074         }
1075         __set_current_state(TASK_RUNNING);
1076
1077         if (!kthread_should_stop())
1078                 goto repeat;
1079
1080         P9_DPRINTK(P9_DEBUG_TRANS, "finish\n");
1081         return 0;
1082 }
1083
1084 int p9_trans_fd_init(void)
1085 {
1086         p9_mux_wq = create_workqueue("v9fs");
1087         if (!p9_mux_wq) {
1088                 printk(KERN_WARNING "v9fs: mux: creating workqueue failed\n");
1089                 return -ENOMEM;
1090         }
1091
1092         p9_poll_task = kthread_run(p9_poll_proc, NULL, "v9fs-poll");
1093         if (IS_ERR(p9_poll_task)) {
1094                 destroy_workqueue(p9_mux_wq);
1095                 printk(KERN_WARNING "v9fs: mux: creating poll task failed\n");
1096                 return PTR_ERR(p9_poll_task);
1097         }
1098
1099         v9fs_register_trans(&p9_tcp_trans);
1100         v9fs_register_trans(&p9_unix_trans);
1101         v9fs_register_trans(&p9_fd_trans);
1102
1103         return 0;
1104 }
1105
1106 void p9_trans_fd_exit(void)
1107 {
1108         kthread_stop(p9_poll_task);
1109         v9fs_unregister_trans(&p9_tcp_trans);
1110         v9fs_unregister_trans(&p9_unix_trans);
1111         v9fs_unregister_trans(&p9_fd_trans);
1112
1113         destroy_workqueue(p9_mux_wq);
1114 }