drivers/misc/sgi-xp/xpc_channel.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (c) 2004-2008 Silicon Graphics, Inc.  All Rights Reserved.
   7  */
   8
   9 /*
  10  * Cross Partition Communication (XPC) channel support.
  11  *
  12  *      This is the part of XPC that manages the channels and
  13  *      sends/receives messages across them to/from other partitions.
  14  *
  15  */
  16
  17 #include <linux/device.h>
  18 #include "xpc.h"
  19
  20 /*
  21  * Process a connect message from a remote partition.
  22  *
  23  * Note: xpc_process_connect() is expecting to be called with the
  24  * spin_lock_irqsave held and will leave it locked upon return.
  25  */
  26 static void
  27 xpc_process_connect(struct xpc_channel *ch, unsigned long *irq_flags)
  28 {
  29         enum xp_retval ret;
  30
  31         DBUG_ON(!spin_is_locked(&ch->lock));
  32
  33         if (!(ch->flags & XPC_C_OPENREQUEST) ||
  34             !(ch->flags & XPC_C_ROPENREQUEST)) {
  35                 /* nothing more to do for now */
  36                 return;
  37         }
  38         DBUG_ON(!(ch->flags & XPC_C_CONNECTING));
  39
  40         if (!(ch->flags & XPC_C_SETUP)) {
  41                 spin_unlock_irqrestore(&ch->lock, *irq_flags);
  42                 ret = xpc_setup_msg_structures(ch);
  43                 spin_lock_irqsave(&ch->lock, *irq_flags);
  44
  45                 if (ret != xpSuccess)
  46                         XPC_DISCONNECT_CHANNEL(ch, ret, irq_flags);
  47
  48                 ch->flags |= XPC_C_SETUP;
  49
  50                 if (ch->flags & (XPC_C_CONNECTED | XPC_C_DISCONNECTING))
  51                         return;
  52
  53                 DBUG_ON(ch->local_msgqueue == NULL);
  54                 DBUG_ON(ch->remote_msgqueue == NULL);
  55         }
  56
  57         if (!(ch->flags & XPC_C_OPENREPLY)) {
  58                 ch->flags |= XPC_C_OPENREPLY;
  59                 xpc_send_chctl_openreply(ch, irq_flags);
  60         }
  61
  62         if (!(ch->flags & XPC_C_ROPENREPLY))
  63                 return;
  64
  65         ch->flags = (XPC_C_CONNECTED | XPC_C_SETUP);    /* clear all else */
  66
  67         dev_info(xpc_chan, "channel %d to partition %d connected\n",
  68                  ch->number, ch->partid);
  69
  70         spin_unlock_irqrestore(&ch->lock, *irq_flags);
  71         xpc_create_kthreads(ch, 1, 0);
  72         spin_lock_irqsave(&ch->lock, *irq_flags);
  73 }
  74
  75 /*
  76  * spin_lock_irqsave() is expected to be held on entry.
  77  */
  78 static void
  79 xpc_process_disconnect(struct xpc_channel *ch, unsigned long *irq_flags)
  80 {
  81         struct xpc_partition *part = &xpc_partitions[ch->partid];
  82         u32 channel_was_connected = (ch->flags & XPC_C_WASCONNECTED);
  83
  84         DBUG_ON(!spin_is_locked(&ch->lock));
  85
  86         if (!(ch->flags & XPC_C_DISCONNECTING))
  87                 return;
  88
  89         DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
  90
  91         /* make sure all activity has settled down first */
  92
  93         if (atomic_read(&ch->kthreads_assigned) > 0 ||
  94             atomic_read(&ch->references) > 0) {
  95                 return;
  96         }
  97         DBUG_ON((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
  98                 !(ch->flags & XPC_C_DISCONNECTINGCALLOUT_MADE));
  99
 100         if (part->act_state == XPC_P_AS_DEACTIVATING) {
 101                 /* can't proceed until the other side disengages from us */
 102                 if (xpc_partition_engaged(ch->partid))
 103                         return;
 104
 105         } else {
 106
 107                 /* as long as the other side is up do the full protocol */
 108
 109                 if (!(ch->flags & XPC_C_RCLOSEREQUEST))
 110                         return;
 111
 112                 if (!(ch->flags & XPC_C_CLOSEREPLY)) {
 113                         ch->flags |= XPC_C_CLOSEREPLY;
 114                         xpc_send_chctl_closereply(ch, irq_flags);
 115                 }
 116
 117                 if (!(ch->flags & XPC_C_RCLOSEREPLY))
 118                         return;
 119         }
 120
 121         /* wake those waiting for notify completion */
 122         if (atomic_read(&ch->n_to_notify) > 0) {
 123                 /* we do callout while holding ch->lock, callout can't block */
 124                 xpc_notify_senders_of_disconnect(ch);
 125         }
 126
 127         /* both sides are disconnected now */
 128
 129         if (ch->flags & XPC_C_DISCONNECTINGCALLOUT_MADE) {
 130                 spin_unlock_irqrestore(&ch->lock, *irq_flags);
 131                 xpc_disconnect_callout(ch, xpDisconnected);
 132                 spin_lock_irqsave(&ch->lock, *irq_flags);
 133         }
 134
 135         DBUG_ON(atomic_read(&ch->n_to_notify) != 0);
 136
 137         /* it's now safe to free the channel's message queues */
 138         xpc_teardown_msg_structures(ch);
 139
 140         ch->func = NULL;
 141         ch->key = NULL;
 142         ch->entry_size = 0;
 143         ch->local_nentries = 0;
 144         ch->remote_nentries = 0;
 145         ch->kthreads_assigned_limit = 0;
 146         ch->kthreads_idle_limit = 0;
 147
 148         /*
 149          * Mark the channel disconnected and clear all other flags, including
 150          * XPC_C_SETUP (because of call to xpc_teardown_msg_structures()) but
 151          * not including XPC_C_WDISCONNECT (if it was set).
 152          */
 153         ch->flags = (XPC_C_DISCONNECTED | (ch->flags & XPC_C_WDISCONNECT));
 154
 155         atomic_dec(&part->nchannels_active);
 156
 157         if (channel_was_connected) {
 158                 dev_info(xpc_chan, "channel %d to partition %d disconnected, "
 159                          "reason=%d\n", ch->number, ch->partid, ch->reason);
 160         }
 161
 162         if (ch->flags & XPC_C_WDISCONNECT) {
 163                 /* we won't lose the CPU since we're holding ch->lock */
 164                 complete(&ch->wdisconnect_wait);
 165         } else if (ch->delayed_chctl_flags) {
 166                 if (part->act_state != XPC_P_AS_DEACTIVATING) {
 167                         /* time to take action on any delayed chctl flags */
 168                         spin_lock(&part->chctl_lock);
 169                         part->chctl.flags[ch->number] |=
 170                             ch->delayed_chctl_flags;
 171                         spin_unlock(&part->chctl_lock);
 172                 }
 173                 ch->delayed_chctl_flags = 0;
 174         }
 175 }
 176
 177 /*
 178  * Process a change in the channel's remote connection state.
 179  */
 180 static void
 181 xpc_process_openclose_chctl_flags(struct xpc_partition *part, int ch_number,
 182                                   u8 chctl_flags)
 183 {
 184         unsigned long irq_flags;
 185         struct xpc_openclose_args *args =
 186             &part->remote_openclose_args[ch_number];
 187         struct xpc_channel *ch = &part->channels[ch_number];
 188         enum xp_retval reason;
 189
 190         spin_lock_irqsave(&ch->lock, irq_flags);
 191
 192 again:
 193
 194         if ((ch->flags & XPC_C_DISCONNECTED) &&
 195             (ch->flags & XPC_C_WDISCONNECT)) {
 196                 /*
 197                  * Delay processing chctl flags until thread waiting disconnect
 198                  * has had a chance to see that the channel is disconnected.
 199                  */
 200                 ch->delayed_chctl_flags |= chctl_flags;
 201                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 202                 return;
 203         }
 204
 205         if (chctl_flags & XPC_CHCTL_CLOSEREQUEST) {
 206
 207                 dev_dbg(xpc_chan, "XPC_CHCTL_CLOSEREQUEST (reason=%d) received "
 208                         "from partid=%d, channel=%d\n", args->reason,
 209                         ch->partid, ch->number);
 210
 211                 /*
 212                  * If RCLOSEREQUEST is set, we're probably waiting for
 213                  * RCLOSEREPLY. We should find it and a ROPENREQUEST packed
 214                  * with this RCLOSEREQUEST in the chctl_flags.
 215                  */
 216
 217                 if (ch->flags & XPC_C_RCLOSEREQUEST) {
 218                         DBUG_ON(!(ch->flags & XPC_C_DISCONNECTING));
 219                         DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
 220                         DBUG_ON(!(ch->flags & XPC_C_CLOSEREPLY));
 221                         DBUG_ON(ch->flags & XPC_C_RCLOSEREPLY);
 222
 223                         DBUG_ON(!(chctl_flags & XPC_CHCTL_CLOSEREPLY));
 224                         chctl_flags &= ~XPC_CHCTL_CLOSEREPLY;
 225                         ch->flags |= XPC_C_RCLOSEREPLY;
 226
 227                         /* both sides have finished disconnecting */
 228                         xpc_process_disconnect(ch, &irq_flags);
 229                         DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
 230                         goto again;
 231                 }
 232
 233                 if (ch->flags & XPC_C_DISCONNECTED) {
 234                         if (!(chctl_flags & XPC_CHCTL_OPENREQUEST)) {
 235                                 if (part->chctl.flags[ch_number] &
 236                                     XPC_CHCTL_OPENREQUEST) {
 237
 238                                         DBUG_ON(ch->delayed_chctl_flags != 0);
 239                                         spin_lock(&part->chctl_lock);
 240                                         part->chctl.flags[ch_number] |=
 241                                             XPC_CHCTL_CLOSEREQUEST;
 242                                         spin_unlock(&part->chctl_lock);
 243                                 }
 244                                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 245                                 return;
 246                         }
 247
 248                         XPC_SET_REASON(ch, 0, 0);
 249                         ch->flags &= ~XPC_C_DISCONNECTED;
 250
 251                         atomic_inc(&part->nchannels_active);
 252                         ch->flags |= (XPC_C_CONNECTING | XPC_C_ROPENREQUEST);
 253                 }
 254
 255                 chctl_flags &= ~(XPC_CHCTL_OPENREQUEST | XPC_CHCTL_OPENREPLY);
 256
 257                 /*
 258                  * The meaningful CLOSEREQUEST connection state fields are:
 259                  *      reason = reason connection is to be closed
 260                  */
 261
 262                 ch->flags |= XPC_C_RCLOSEREQUEST;
 263
 264                 if (!(ch->flags & XPC_C_DISCONNECTING)) {
 265                         reason = args->reason;
 266                         if (reason <= xpSuccess || reason > xpUnknownReason)
 267                                 reason = xpUnknownReason;
 268                         else if (reason == xpUnregistering)
 269                                 reason = xpOtherUnregistering;
 270
 271                         XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags);
 272
 273                         DBUG_ON(chctl_flags & XPC_CHCTL_CLOSEREPLY);
 274                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 275                         return;
 276                 }
 277
 278                 xpc_process_disconnect(ch, &irq_flags);
 279         }
 280
 281         if (chctl_flags & XPC_CHCTL_CLOSEREPLY) {
 282
 283                 dev_dbg(xpc_chan, "XPC_CHCTL_CLOSEREPLY received from partid="
 284                         "%d, channel=%d\n", ch->partid, ch->number);
 285
 286                 if (ch->flags & XPC_C_DISCONNECTED) {
 287                         DBUG_ON(part->act_state != XPC_P_AS_DEACTIVATING);
 288                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 289                         return;
 290                 }
 291
 292                 DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
 293
 294                 if (!(ch->flags & XPC_C_RCLOSEREQUEST)) {
 295                         if (part->chctl.flags[ch_number] &
 296                             XPC_CHCTL_CLOSEREQUEST) {
 297
 298                                 DBUG_ON(ch->delayed_chctl_flags != 0);
 299                                 spin_lock(&part->chctl_lock);
 300                                 part->chctl.flags[ch_number] |=
 301                                     XPC_CHCTL_CLOSEREPLY;
 302                                 spin_unlock(&part->chctl_lock);
 303                         }
 304                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 305                         return;
 306                 }
 307
 308                 ch->flags |= XPC_C_RCLOSEREPLY;
 309
 310                 if (ch->flags & XPC_C_CLOSEREPLY) {
 311                         /* both sides have finished disconnecting */
 312                         xpc_process_disconnect(ch, &irq_flags);
 313                 }
 314         }
 315
 316         if (chctl_flags & XPC_CHCTL_OPENREQUEST) {
 317
 318                 dev_dbg(xpc_chan, "XPC_CHCTL_OPENREQUEST (entry_size=%d, "
 319                         "local_nentries=%d) received from partid=%d, "
 320                         "channel=%d\n", args->entry_size, args->local_nentries,
 321                         ch->partid, ch->number);
 322
 323                 if (part->act_state == XPC_P_AS_DEACTIVATING ||
 324                     (ch->flags & XPC_C_ROPENREQUEST)) {
 325                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 326                         return;
 327                 }
 328
 329                 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_WDISCONNECT)) {
 330                         ch->delayed_chctl_flags |= XPC_CHCTL_OPENREQUEST;
 331                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 332                         return;
 333                 }
 334                 DBUG_ON(!(ch->flags & (XPC_C_DISCONNECTED |
 335                                        XPC_C_OPENREQUEST)));
 336                 DBUG_ON(ch->flags & (XPC_C_ROPENREQUEST | XPC_C_ROPENREPLY |
 337                                      XPC_C_OPENREPLY | XPC_C_CONNECTED));
 338
 339                 /*
 340                  * The meaningful OPENREQUEST connection state fields are:
 341                  *      entry_size = size of channel's messages in bytes
 342                  *      local_nentries = remote partition's local_nentries
 343                  */
 344                 if (args->entry_size == 0 || args->local_nentries == 0) {
 345                         /* assume OPENREQUEST was delayed by mistake */
 346                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 347                         return;
 348                 }
 349
 350                 ch->flags |= (XPC_C_ROPENREQUEST | XPC_C_CONNECTING);
 351                 ch->remote_nentries = args->local_nentries;
 352
 353                 if (ch->flags & XPC_C_OPENREQUEST) {
 354                         if (args->entry_size != ch->entry_size) {
 355                                 XPC_DISCONNECT_CHANNEL(ch, xpUnequalMsgSizes,
 356                                                        &irq_flags);
 357                                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 358                                 return;
 359                         }
 360                 } else {
 361                         ch->entry_size = args->entry_size;
 362
 363                         XPC_SET_REASON(ch, 0, 0);
 364                         ch->flags &= ~XPC_C_DISCONNECTED;
 365
 366                         atomic_inc(&part->nchannels_active);
 367                 }
 368
 369                 xpc_process_connect(ch, &irq_flags);
 370         }
 371
 372         if (chctl_flags & XPC_CHCTL_OPENREPLY) {
 373
 374                 dev_dbg(xpc_chan, "XPC_CHCTL_OPENREPLY (local_msgqueue_pa="
 375                         "0x%lx, local_nentries=%d, remote_nentries=%d) "
 376                         "received from partid=%d, channel=%d\n",
 377                         args->local_msgqueue_pa, args->local_nentries,
 378                         args->remote_nentries, ch->partid, ch->number);
 379
 380                 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED)) {
 381                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 382                         return;
 383                 }
 384                 if (!(ch->flags & XPC_C_OPENREQUEST)) {
 385                         XPC_DISCONNECT_CHANNEL(ch, xpOpenCloseError,
 386                                                &irq_flags);
 387                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 388                         return;
 389                 }
 390
 391                 DBUG_ON(!(ch->flags & XPC_C_ROPENREQUEST));
 392                 DBUG_ON(ch->flags & XPC_C_CONNECTED);
 393
 394                 /*
 395                  * The meaningful OPENREPLY connection state fields are:
 396                  *      local_msgqueue_pa = physical address of remote
 397                  *                          partition's local_msgqueue
 398                  *      local_nentries = remote partition's local_nentries
 399                  *      remote_nentries = remote partition's remote_nentries
 400                  */
 401                 DBUG_ON(args->local_msgqueue_pa == 0);
 402                 DBUG_ON(args->local_nentries == 0);
 403                 DBUG_ON(args->remote_nentries == 0);
 404
 405                 ch->flags |= XPC_C_ROPENREPLY;
 406                 xpc_save_remote_msgqueue_pa(ch, args->local_msgqueue_pa);
 407
 408                 if (args->local_nentries < ch->remote_nentries) {
 409                         dev_dbg(xpc_chan, "XPC_CHCTL_OPENREPLY: new "
 410                                 "remote_nentries=%d, old remote_nentries=%d, "
 411                                 "partid=%d, channel=%d\n",
 412                                 args->local_nentries, ch->remote_nentries,
 413                                 ch->partid, ch->number);
 414
 415                         ch->remote_nentries = args->local_nentries;
 416                 }
 417                 if (args->remote_nentries < ch->local_nentries) {
 418                         dev_dbg(xpc_chan, "XPC_CHCTL_OPENREPLY: new "
 419                                 "local_nentries=%d, old local_nentries=%d, "
 420                                 "partid=%d, channel=%d\n",
 421                                 args->remote_nentries, ch->local_nentries,
 422                                 ch->partid, ch->number);
 423
 424                         ch->local_nentries = args->remote_nentries;
 425                 }
 426
 427                 xpc_process_connect(ch, &irq_flags);
 428         }
 429
 430         spin_unlock_irqrestore(&ch->lock, irq_flags);
 431 }
 432
 433 /*
 434  * Attempt to establish a channel connection to a remote partition.
 435  */
 436 static enum xp_retval
 437 xpc_connect_channel(struct xpc_channel *ch)
 438 {
 439         unsigned long irq_flags;
 440         struct xpc_registration *registration = &xpc_registrations[ch->number];
 441
 442         if (mutex_trylock(&registration->mutex) == 0)
 443                 return xpRetry;
 444
 445         if (!XPC_CHANNEL_REGISTERED(ch->number)) {
 446                 mutex_unlock(&registration->mutex);
 447                 return xpUnregistered;
 448         }
 449
 450         spin_lock_irqsave(&ch->lock, irq_flags);
 451
 452         DBUG_ON(ch->flags & XPC_C_CONNECTED);
 453         DBUG_ON(ch->flags & XPC_C_OPENREQUEST);
 454
 455         if (ch->flags & XPC_C_DISCONNECTING) {
 456                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 457                 mutex_unlock(&registration->mutex);
 458                 return ch->reason;
 459         }
 460
 461         /* add info from the channel connect registration to the channel */
 462
 463         ch->kthreads_assigned_limit = registration->assigned_limit;
 464         ch->kthreads_idle_limit = registration->idle_limit;
 465         DBUG_ON(atomic_read(&ch->kthreads_assigned) != 0);
 466         DBUG_ON(atomic_read(&ch->kthreads_idle) != 0);
 467         DBUG_ON(atomic_read(&ch->kthreads_active) != 0);
 468
 469         ch->func = registration->func;
 470         DBUG_ON(registration->func == NULL);
 471         ch->key = registration->key;
 472
 473         ch->local_nentries = registration->nentries;
 474
 475         if (ch->flags & XPC_C_ROPENREQUEST) {
 476                 if (registration->entry_size != ch->entry_size) {
 477                         /* the local and remote sides aren't the same */
 478
 479                         /*
 480                          * Because XPC_DISCONNECT_CHANNEL() can block we're
 481                          * forced to up the registration sema before we unlock
 482                          * the channel lock. But that's okay here because we're
 483                          * done with the part that required the registration
 484                          * sema. XPC_DISCONNECT_CHANNEL() requires that the
 485                          * channel lock be locked and will unlock and relock
 486                          * the channel lock as needed.
 487                          */
 488                         mutex_unlock(&registration->mutex);
 489                         XPC_DISCONNECT_CHANNEL(ch, xpUnequalMsgSizes,
 490                                                &irq_flags);
 491                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 492                         return xpUnequalMsgSizes;
 493                 }
 494         } else {
 495                 ch->entry_size = registration->entry_size;
 496
 497                 XPC_SET_REASON(ch, 0, 0);
 498                 ch->flags &= ~XPC_C_DISCONNECTED;
 499
 500                 atomic_inc(&xpc_partitions[ch->partid].nchannels_active);
 501         }
 502
 503         mutex_unlock(&registration->mutex);
 504
 505         /* initiate the connection */
 506
 507         ch->flags |= (XPC_C_OPENREQUEST | XPC_C_CONNECTING);
 508         xpc_send_chctl_openrequest(ch, &irq_flags);
 509
 510         xpc_process_connect(ch, &irq_flags);
 511
 512         spin_unlock_irqrestore(&ch->lock, irq_flags);
 513
 514         return xpSuccess;
 515 }
 516
 517 void
 518 xpc_process_sent_chctl_flags(struct xpc_partition *part)
 519 {
 520         unsigned long irq_flags;
 521         union xpc_channel_ctl_flags chctl;
 522         struct xpc_channel *ch;
 523         int ch_number;
 524         u32 ch_flags;
 525
 526         chctl.all_flags = xpc_get_chctl_all_flags(part);
 527
 528         /*
 529          * Initiate channel connections for registered channels.
 530          *
 531          * For each connected channel that has pending messages activate idle
 532          * kthreads and/or create new kthreads as needed.
 533          */
 534
 535         for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
 536                 ch = &part->channels[ch_number];
 537
 538                 /*
 539                  * Process any open or close related chctl flags, and then deal
 540                  * with connecting or disconnecting the channel as required.
 541                  */
 542
 543                 if (chctl.flags[ch_number] & XPC_OPENCLOSE_CHCTL_FLAGS) {
 544                         xpc_process_openclose_chctl_flags(part, ch_number,
 545                                                         chctl.flags[ch_number]);
 546                 }
 547
 548                 ch_flags = ch->flags;   /* need an atomic snapshot of flags */
 549
 550                 if (ch_flags & XPC_C_DISCONNECTING) {
 551                         spin_lock_irqsave(&ch->lock, irq_flags);
 552                         xpc_process_disconnect(ch, &irq_flags);
 553                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 554                         continue;
 555                 }
 556
 557                 if (part->act_state == XPC_P_AS_DEACTIVATING)
 558                         continue;
 559
 560                 if (!(ch_flags & XPC_C_CONNECTED)) {
 561                         if (!(ch_flags & XPC_C_OPENREQUEST)) {
 562                                 DBUG_ON(ch_flags & XPC_C_SETUP);
 563                                 (void)xpc_connect_channel(ch);
 564                         } else {
 565                                 spin_lock_irqsave(&ch->lock, irq_flags);
 566                                 xpc_process_connect(ch, &irq_flags);
 567                                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 568                         }
 569                         continue;
 570                 }
 571
 572                 /*
 573                  * Process any message related chctl flags, this may involve
 574                  * the activation of kthreads to deliver any pending messages
 575                  * sent from the other partition.
 576                  */
 577
 578                 if (chctl.flags[ch_number] & XPC_MSG_CHCTL_FLAGS)
 579                         xpc_process_msg_chctl_flags(part, ch_number);
 580         }
 581 }
 582
 583 /*
 584  * XPC's heartbeat code calls this function to inform XPC that a partition is
 585  * going down.  XPC responds by tearing down the XPartition Communication
 586  * infrastructure used for the just downed partition.
 587  *
 588  * XPC's heartbeat code will never call this function and xpc_partition_up()
 589  * at the same time. Nor will it ever make multiple calls to either function
 590  * at the same time.
 591  */
 592 void
 593 xpc_partition_going_down(struct xpc_partition *part, enum xp_retval reason)
 594 {
 595         unsigned long irq_flags;
 596         int ch_number;
 597         struct xpc_channel *ch;
 598
 599         dev_dbg(xpc_chan, "deactivating partition %d, reason=%d\n",
 600                 XPC_PARTID(part), reason);
 601
 602         if (!xpc_part_ref(part)) {
 603                 /* infrastructure for this partition isn't currently set up */
 604                 return;
 605         }
 606
 607         /* disconnect channels associated with the partition going down */
 608
 609         for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
 610                 ch = &part->channels[ch_number];
 611
 612                 xpc_msgqueue_ref(ch);
 613                 spin_lock_irqsave(&ch->lock, irq_flags);
 614
 615                 XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags);
 616
 617                 spin_unlock_irqrestore(&ch->lock, irq_flags);
 618                 xpc_msgqueue_deref(ch);
 619         }
 620
 621         xpc_wakeup_channel_mgr(part);
 622
 623         xpc_part_deref(part);
 624 }
 625
 626 /*
 627  * Called by XP at the time of channel connection registration to cause
 628  * XPC to establish connections to all currently active partitions.
 629  */
 630 void
 631 xpc_initiate_connect(int ch_number)
 632 {
 633         short partid;
 634         struct xpc_partition *part;
 635         struct xpc_channel *ch;
 636
 637         DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
 638
 639         for (partid = 0; partid < xp_max_npartitions; partid++) {
 640                 part = &xpc_partitions[partid];
 641
 642                 if (xpc_part_ref(part)) {
 643                         ch = &part->channels[ch_number];
 644
 645                         /*
 646                          * Initiate the establishment of a connection on the
 647                          * newly registered channel to the remote partition.
 648                          */
 649                         xpc_wakeup_channel_mgr(part);
 650                         xpc_part_deref(part);
 651                 }
 652         }
 653 }
 654
 655 void
 656 xpc_connected_callout(struct xpc_channel *ch)
 657 {
 658         /* let the registerer know that a connection has been established */
 659
 660         if (ch->func != NULL) {
 661                 dev_dbg(xpc_chan, "ch->func() called, reason=xpConnected, "
 662                         "partid=%d, channel=%d\n", ch->partid, ch->number);
 663
 664                 ch->func(xpConnected, ch->partid, ch->number,
 665                          (void *)(u64)ch->local_nentries, ch->key);
 666
 667                 dev_dbg(xpc_chan, "ch->func() returned, reason=xpConnected, "
 668                         "partid=%d, channel=%d\n", ch->partid, ch->number);
 669         }
 670 }
 671
 672 /*
 673  * Called by XP at the time of channel connection unregistration to cause
 674  * XPC to teardown all current connections for the specified channel.
 675  *
 676  * Before returning xpc_initiate_disconnect() will wait until all connections
 677  * on the specified channel have been closed/torndown. So the caller can be
 678  * assured that they will not be receiving any more callouts from XPC to the
 679  * function they registered via xpc_connect().
 680  *
 681  * Arguments:
 682  *
 683  *      ch_number - channel # to unregister.
 684  */
 685 void
 686 xpc_initiate_disconnect(int ch_number)
 687 {
 688         unsigned long irq_flags;
 689         short partid;
 690         struct xpc_partition *part;
 691         struct xpc_channel *ch;
 692
 693         DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
 694
 695         /* initiate the channel disconnect for every active partition */
 696         for (partid = 0; partid < xp_max_npartitions; partid++) {
 697                 part = &xpc_partitions[partid];
 698
 699                 if (xpc_part_ref(part)) {
 700                         ch = &part->channels[ch_number];
 701                         xpc_msgqueue_ref(ch);
 702
 703                         spin_lock_irqsave(&ch->lock, irq_flags);
 704
 705                         if (!(ch->flags & XPC_C_DISCONNECTED)) {
 706                                 ch->flags |= XPC_C_WDISCONNECT;
 707
 708                                 XPC_DISCONNECT_CHANNEL(ch, xpUnregistering,
 709                                                        &irq_flags);
 710                         }
 711
 712                         spin_unlock_irqrestore(&ch->lock, irq_flags);
 713
 714                         xpc_msgqueue_deref(ch);
 715                         xpc_part_deref(part);
 716                 }
 717         }
 718
 719         xpc_disconnect_wait(ch_number);
 720 }
 721
 722 /*
 723  * To disconnect a channel, and reflect it back to all who may be waiting.
 724  *
 725  * An OPEN is not allowed until XPC_C_DISCONNECTING is cleared by
 726  * xpc_process_disconnect(), and if set, XPC_C_WDISCONNECT is cleared by
 727  * xpc_disconnect_wait().
 728  *
 729  * THE CHANNEL IS TO BE LOCKED BY THE CALLER AND WILL REMAIN LOCKED UPON RETURN.
 730  */
 731 void
 732 xpc_disconnect_channel(const int line, struct xpc_channel *ch,
 733                        enum xp_retval reason, unsigned long *irq_flags)
 734 {
 735         u32 channel_was_connected = (ch->flags & XPC_C_CONNECTED);
 736
 737         DBUG_ON(!spin_is_locked(&ch->lock));
 738
 739         if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))
 740                 return;
 741
 742         DBUG_ON(!(ch->flags & (XPC_C_CONNECTING | XPC_C_CONNECTED)));
 743
 744         dev_dbg(xpc_chan, "reason=%d, line=%d, partid=%d, channel=%d\n",
 745                 reason, line, ch->partid, ch->number);
 746
 747         XPC_SET_REASON(ch, reason, line);
 748
 749         ch->flags |= (XPC_C_CLOSEREQUEST | XPC_C_DISCONNECTING);
 750         /* some of these may not have been set */
 751         ch->flags &= ~(XPC_C_OPENREQUEST | XPC_C_OPENREPLY |
 752                        XPC_C_ROPENREQUEST | XPC_C_ROPENREPLY |
 753                        XPC_C_CONNECTING | XPC_C_CONNECTED);
 754
 755         xpc_send_chctl_closerequest(ch, irq_flags);
 756
 757         if (channel_was_connected)
 758                 ch->flags |= XPC_C_WASCONNECTED;
 759
 760         spin_unlock_irqrestore(&ch->lock, *irq_flags);
 761
 762         /* wake all idle kthreads so they can exit */
 763         if (atomic_read(&ch->kthreads_idle) > 0) {
 764                 wake_up_all(&ch->idle_wq);
 765
 766         } else if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
 767                    !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
 768                 /* start a kthread that will do the xpDisconnecting callout */
 769                 xpc_create_kthreads(ch, 1, 1);
 770         }
 771
 772         /* wake those waiting to allocate an entry from the local msg queue */
 773         if (atomic_read(&ch->n_on_msg_allocate_wq) > 0)
 774                 wake_up(&ch->msg_allocate_wq);
 775
 776         spin_lock_irqsave(&ch->lock, *irq_flags);
 777 }
 778
 779 void
 780 xpc_disconnect_callout(struct xpc_channel *ch, enum xp_retval reason)
 781 {
 782         /*
 783          * Let the channel's registerer know that the channel is being
 784          * disconnected. We don't want to do this if the registerer was never
 785          * informed of a connection being made.
 786          */
 787
 788         if (ch->func != NULL) {
 789                 dev_dbg(xpc_chan, "ch->func() called, reason=%d, partid=%d, "
 790                         "channel=%d\n", reason, ch->partid, ch->number);
 791
 792                 ch->func(reason, ch->partid, ch->number, NULL, ch->key);
 793
 794                 dev_dbg(xpc_chan, "ch->func() returned, reason=%d, partid=%d, "
 795                         "channel=%d\n", reason, ch->partid, ch->number);
 796         }
 797 }
 798
 799 /*
 800  * Wait for a message entry to become available for the specified channel,
 801  * but don't wait any longer than 1 jiffy.
 802  */
 803 enum xp_retval
 804 xpc_allocate_msg_wait(struct xpc_channel *ch)
 805 {
 806         enum xp_retval ret;
 807
 808         if (ch->flags & XPC_C_DISCONNECTING) {
 809                 DBUG_ON(ch->reason == xpInterrupted);
 810                 return ch->reason;
 811         }
 812
 813         atomic_inc(&ch->n_on_msg_allocate_wq);
 814         ret = interruptible_sleep_on_timeout(&ch->msg_allocate_wq, 1);
 815         atomic_dec(&ch->n_on_msg_allocate_wq);
 816
 817         if (ch->flags & XPC_C_DISCONNECTING) {
 818                 ret = ch->reason;
 819                 DBUG_ON(ch->reason == xpInterrupted);
 820         } else if (ret == 0) {
 821                 ret = xpTimeout;
 822         } else {
 823                 ret = xpInterrupted;
 824         }
 825
 826         return ret;
 827 }
 828
 829 /*
 830  * Send a message that contains the user's payload on the specified channel
 831  * connected to the specified partition.
 832  *
 833  * NOTE that this routine can sleep waiting for a message entry to become
 834  * available. To not sleep, pass in the XPC_NOWAIT flag.
 835  *
 836  * Once sent, this routine will not wait for the message to be received, nor
 837  * will notification be given when it does happen.
 838  *
 839  * Arguments:
 840  *
 841  *      partid - ID of partition to which the channel is connected.
 842  *      ch_number - channel # to send message on.
 843  *      flags - see xp.h for valid flags.
 844  *      payload - pointer to the payload which is to be sent.
 845  *      payload_size - size of the payload in bytes.
 846  */
 847 enum xp_retval
 848 xpc_initiate_send(short partid, int ch_number, u32 flags, void *payload,
 849                   u16 payload_size)
 850 {
 851         struct xpc_partition *part = &xpc_partitions[partid];
 852         enum xp_retval ret = xpUnknownReason;
 853
 854         dev_dbg(xpc_chan, "payload=0x%p, partid=%d, channel=%d\n", payload,
 855                 partid, ch_number);
 856
 857         DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
 858         DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
 859         DBUG_ON(payload == NULL);
 860
 861         if (xpc_part_ref(part)) {
 862                 ret = xpc_send_payload(&part->channels[ch_number], flags,
 863                                        payload, payload_size, 0, NULL, NULL);
 864                 xpc_part_deref(part);
 865         }
 866
 867         return ret;
 868 }
 869
 870 /*
 871  * Send a message that contains the user's payload on the specified channel
 872  * connected to the specified partition.
 873  *
 874  * NOTE that this routine can sleep waiting for a message entry to become
 875  * available. To not sleep, pass in the XPC_NOWAIT flag.
 876  *
 877  * This routine will not wait for the message to be sent or received.
 878  *
 879  * Once the remote end of the channel has received the message, the function
 880  * passed as an argument to xpc_initiate_send_notify() will be called. This
 881  * allows the sender to free up or re-use any buffers referenced by the
 882  * message, but does NOT mean the message has been processed at the remote
 883  * end by a receiver.
 884  *
 885  * If this routine returns an error, the caller's function will NOT be called.
 886  *
 887  * Arguments:
 888  *
 889  *      partid - ID of partition to which the channel is connected.
 890  *      ch_number - channel # to send message on.
 891  *      flags - see xp.h for valid flags.
 892  *      payload - pointer to the payload which is to be sent.
 893  *      payload_size - size of the payload in bytes.
 894  *      func - function to call with asynchronous notification of message
 895  *                receipt. THIS FUNCTION MUST BE NON-BLOCKING.
 896  *      key - user-defined key to be passed to the function when it's called.
 897  */
 898 enum xp_retval
 899 xpc_initiate_send_notify(short partid, int ch_number, u32 flags, void *payload,
 900                          u16 payload_size, xpc_notify_func func, void *key)
 901 {
 902         struct xpc_partition *part = &xpc_partitions[partid];
 903         enum xp_retval ret = xpUnknownReason;
 904
 905         dev_dbg(xpc_chan, "payload=0x%p, partid=%d, channel=%d\n", payload,
 906                 partid, ch_number);
 907
 908         DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
 909         DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
 910         DBUG_ON(payload == NULL);
 911         DBUG_ON(func == NULL);
 912
 913         if (xpc_part_ref(part)) {
 914                 ret = xpc_send_payload(&part->channels[ch_number], flags,
 915                                        payload, payload_size, XPC_N_CALL, func,
 916                                        key);
 917                 xpc_part_deref(part);
 918         }
 919         return ret;
 920 }
 921
 922 /*
 923  * Deliver a message's payload to its intended recipient.
 924  */
 925 void
 926 xpc_deliver_payload(struct xpc_channel *ch)
 927 {
 928         void *payload;
 929
 930         payload = xpc_get_deliverable_payload(ch);
 931         if (payload != NULL) {
 932
 933                 /*
 934                  * This ref is taken to protect the payload itself from being
 935                  * freed before the user is finished with it, which the user
 936                  * indicates by calling xpc_initiate_received().
 937                  */
 938                 xpc_msgqueue_ref(ch);
 939
 940                 atomic_inc(&ch->kthreads_active);
 941
 942                 if (ch->func != NULL) {
 943                         dev_dbg(xpc_chan, "ch->func() called, payload=0x%p "
 944                                 "partid=%d channel=%d\n", payload, ch->partid,
 945                                 ch->number);
 946
 947                         /* deliver the message to its intended recipient */
 948                         ch->func(xpMsgReceived, ch->partid, ch->number, payload,
 949                                  ch->key);
 950
 951                         dev_dbg(xpc_chan, "ch->func() returned, payload=0x%p "
 952                                 "partid=%d channel=%d\n", payload, ch->partid,
 953                                 ch->number);
 954                 }
 955
 956                 atomic_dec(&ch->kthreads_active);
 957         }
 958 }
 959
 960 /*
 961  * Acknowledge receipt of a delivered message's payload.
 962  *
 963  * This function, although called by users, does not call xpc_part_ref() to
 964  * ensure that the partition infrastructure is in place. It relies on the
 965  * fact that we called xpc_msgqueue_ref() in xpc_deliver_payload().
 966  *
 967  * Arguments:
 968  *
 969  *      partid - ID of partition to which the channel is connected.
 970  *      ch_number - channel # message received on.
 971  *      payload - pointer to the payload area allocated via
 972  *                      xpc_initiate_send() or xpc_initiate_send_notify().
 973  */
 974 void
 975 xpc_initiate_received(short partid, int ch_number, void *payload)
 976 {
 977         struct xpc_partition *part = &xpc_partitions[partid];
 978         struct xpc_channel *ch;
 979
 980         DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
 981         DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
 982
 983         ch = &part->channels[ch_number];
 984         xpc_received_payload(ch, payload);
 985
 986         /* the call to xpc_msgqueue_ref() was done by xpc_deliver_payload()  */
 987         xpc_msgqueue_deref(ch);
 988 }