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1/*2 * This file is subject to the terms and conditions of the GNU General Public3 * License. See the file "COPYING" in the main directory of this archive4 * for more details.5 *6 * Copyright (c) 2004-2009 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 and13 * 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 the24 * spin_lock_irqsave held and will leave it locked upon return.25 */26static void27xpc_process_connect(struct xpc_channel *ch, unsigned long *irq_flags)28{29 enum xp_retval ret;30 31 lockdep_assert_held(&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_arch_ops.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 else48 ch->flags |= XPC_C_SETUP;49 50 if (ch->flags & XPC_C_DISCONNECTING)51 return;52 }53 54 if (!(ch->flags & XPC_C_OPENREPLY)) {55 ch->flags |= XPC_C_OPENREPLY;56 xpc_arch_ops.send_chctl_openreply(ch, irq_flags);57 }58 59 if (!(ch->flags & XPC_C_ROPENREPLY))60 return;61 62 if (!(ch->flags & XPC_C_OPENCOMPLETE)) {63 ch->flags |= (XPC_C_OPENCOMPLETE | XPC_C_CONNECTED);64 xpc_arch_ops.send_chctl_opencomplete(ch, irq_flags);65 }66 67 if (!(ch->flags & XPC_C_ROPENCOMPLETE))68 return;69 70 dev_info(xpc_chan, "channel %d to partition %d connected\n",71 ch->number, ch->partid);72 73 ch->flags = (XPC_C_CONNECTED | XPC_C_SETUP); /* clear all else */74}75 76/*77 * spin_lock_irqsave() is expected to be held on entry.78 */79static void80xpc_process_disconnect(struct xpc_channel *ch, unsigned long *irq_flags)81{82 struct xpc_partition *part = &xpc_partitions[ch->partid];83 u32 channel_was_connected = (ch->flags & XPC_C_WASCONNECTED);84 85 lockdep_assert_held(&ch->lock);86 87 if (!(ch->flags & XPC_C_DISCONNECTING))88 return;89 90 DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));91 92 /* make sure all activity has settled down first */93 94 if (atomic_read(&ch->kthreads_assigned) > 0 ||95 atomic_read(&ch->references) > 0) {96 return;97 }98 DBUG_ON((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&99 !(ch->flags & XPC_C_DISCONNECTINGCALLOUT_MADE));100 101 if (part->act_state == XPC_P_AS_DEACTIVATING) {102 /* can't proceed until the other side disengages from us */103 if (xpc_arch_ops.partition_engaged(ch->partid))104 return;105 106 } else {107 108 /* as long as the other side is up do the full protocol */109 110 if (!(ch->flags & XPC_C_RCLOSEREQUEST))111 return;112 113 if (!(ch->flags & XPC_C_CLOSEREPLY)) {114 ch->flags |= XPC_C_CLOSEREPLY;115 xpc_arch_ops.send_chctl_closereply(ch, irq_flags);116 }117 118 if (!(ch->flags & XPC_C_RCLOSEREPLY))119 return;120 }121 122 /* wake those waiting for notify completion */123 if (atomic_read(&ch->n_to_notify) > 0) {124 /* we do callout while holding ch->lock, callout can't block */125 xpc_arch_ops.notify_senders_of_disconnect(ch);126 }127 128 /* both sides are disconnected now */129 130 if (ch->flags & XPC_C_DISCONNECTINGCALLOUT_MADE) {131 spin_unlock_irqrestore(&ch->lock, *irq_flags);132 xpc_disconnect_callout(ch, xpDisconnected);133 spin_lock_irqsave(&ch->lock, *irq_flags);134 }135 136 DBUG_ON(atomic_read(&ch->n_to_notify) != 0);137 138 /* it's now safe to free the channel's message queues */139 xpc_arch_ops.teardown_msg_structures(ch);140 141 ch->func = NULL;142 ch->key = NULL;143 ch->entry_size = 0;144 ch->local_nentries = 0;145 ch->remote_nentries = 0;146 ch->kthreads_assigned_limit = 0;147 ch->kthreads_idle_limit = 0;148 149 /*150 * Mark the channel disconnected and clear all other flags, including151 * XPC_C_SETUP (because of call to152 * xpc_arch_ops.teardown_msg_structures()) but not including153 * XPC_C_WDISCONNECT (if it was set).154 */155 ch->flags = (XPC_C_DISCONNECTED | (ch->flags & XPC_C_WDISCONNECT));156 157 atomic_dec(&part->nchannels_active);158 159 if (channel_was_connected) {160 dev_info(xpc_chan, "channel %d to partition %d disconnected, "161 "reason=%d\n", ch->number, ch->partid, ch->reason);162 }163 164 if (ch->flags & XPC_C_WDISCONNECT) {165 /* we won't lose the CPU since we're holding ch->lock */166 complete(&ch->wdisconnect_wait);167 } else if (ch->delayed_chctl_flags) {168 if (part->act_state != XPC_P_AS_DEACTIVATING) {169 /* time to take action on any delayed chctl flags */170 spin_lock(&part->chctl_lock);171 part->chctl.flags[ch->number] |=172 ch->delayed_chctl_flags;173 spin_unlock(&part->chctl_lock);174 }175 ch->delayed_chctl_flags = 0;176 }177}178 179/*180 * Process a change in the channel's remote connection state.181 */182static void183xpc_process_openclose_chctl_flags(struct xpc_partition *part, int ch_number,184 u8 chctl_flags)185{186 unsigned long irq_flags;187 struct xpc_openclose_args *args =188 &part->remote_openclose_args[ch_number];189 struct xpc_channel *ch = &part->channels[ch_number];190 enum xp_retval reason;191 enum xp_retval ret;192 int create_kthread = 0;193 194 spin_lock_irqsave(&ch->lock, irq_flags);195 196again:197 198 if ((ch->flags & XPC_C_DISCONNECTED) &&199 (ch->flags & XPC_C_WDISCONNECT)) {200 /*201 * Delay processing chctl flags until thread waiting disconnect202 * has had a chance to see that the channel is disconnected.203 */204 ch->delayed_chctl_flags |= chctl_flags;205 goto out;206 }207 208 if (chctl_flags & XPC_CHCTL_CLOSEREQUEST) {209 210 dev_dbg(xpc_chan, "XPC_CHCTL_CLOSEREQUEST (reason=%d) received "211 "from partid=%d, channel=%d\n", args->reason,212 ch->partid, ch->number);213 214 /*215 * If RCLOSEREQUEST is set, we're probably waiting for216 * RCLOSEREPLY. We should find it and a ROPENREQUEST packed217 * with this RCLOSEREQUEST in the chctl_flags.218 */219 220 if (ch->flags & XPC_C_RCLOSEREQUEST) {221 DBUG_ON(!(ch->flags & XPC_C_DISCONNECTING));222 DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));223 DBUG_ON(!(ch->flags & XPC_C_CLOSEREPLY));224 DBUG_ON(ch->flags & XPC_C_RCLOSEREPLY);225 226 DBUG_ON(!(chctl_flags & XPC_CHCTL_CLOSEREPLY));227 chctl_flags &= ~XPC_CHCTL_CLOSEREPLY;228 ch->flags |= XPC_C_RCLOSEREPLY;229 230 /* both sides have finished disconnecting */231 xpc_process_disconnect(ch, &irq_flags);232 DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));233 goto again;234 }235 236 if (ch->flags & XPC_C_DISCONNECTED) {237 if (!(chctl_flags & XPC_CHCTL_OPENREQUEST)) {238 if (part->chctl.flags[ch_number] &239 XPC_CHCTL_OPENREQUEST) {240 241 DBUG_ON(ch->delayed_chctl_flags != 0);242 spin_lock(&part->chctl_lock);243 part->chctl.flags[ch_number] |=244 XPC_CHCTL_CLOSEREQUEST;245 spin_unlock(&part->chctl_lock);246 }247 goto out;248 }249 250 XPC_SET_REASON(ch, 0, 0);251 ch->flags &= ~XPC_C_DISCONNECTED;252 253 atomic_inc(&part->nchannels_active);254 ch->flags |= (XPC_C_CONNECTING | XPC_C_ROPENREQUEST);255 }256 257 chctl_flags &= ~(XPC_CHCTL_OPENREQUEST | XPC_CHCTL_OPENREPLY |258 XPC_CHCTL_OPENCOMPLETE);259 260 /*261 * The meaningful CLOSEREQUEST connection state fields are:262 * reason = reason connection is to be closed263 */264 265 ch->flags |= XPC_C_RCLOSEREQUEST;266 267 if (!(ch->flags & XPC_C_DISCONNECTING)) {268 reason = args->reason;269 if (reason <= xpSuccess || reason > xpUnknownReason)270 reason = xpUnknownReason;271 else if (reason == xpUnregistering)272 reason = xpOtherUnregistering;273 274 XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags);275 276 DBUG_ON(chctl_flags & XPC_CHCTL_CLOSEREPLY);277 goto out;278 }279 280 xpc_process_disconnect(ch, &irq_flags);281 }282 283 if (chctl_flags & XPC_CHCTL_CLOSEREPLY) {284 285 dev_dbg(xpc_chan, "XPC_CHCTL_CLOSEREPLY received from partid="286 "%d, channel=%d\n", ch->partid, ch->number);287 288 if (ch->flags & XPC_C_DISCONNECTED) {289 DBUG_ON(part->act_state != XPC_P_AS_DEACTIVATING);290 goto out;291 }292 293 DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));294 295 if (!(ch->flags & XPC_C_RCLOSEREQUEST)) {296 if (part->chctl.flags[ch_number] &297 XPC_CHCTL_CLOSEREQUEST) {298 299 DBUG_ON(ch->delayed_chctl_flags != 0);300 spin_lock(&part->chctl_lock);301 part->chctl.flags[ch_number] |=302 XPC_CHCTL_CLOSEREPLY;303 spin_unlock(&part->chctl_lock);304 }305 goto out;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 goto out;326 }327 328 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_WDISCONNECT)) {329 ch->delayed_chctl_flags |= XPC_CHCTL_OPENREQUEST;330 goto out;331 }332 DBUG_ON(!(ch->flags & (XPC_C_DISCONNECTED |333 XPC_C_OPENREQUEST)));334 DBUG_ON(ch->flags & (XPC_C_ROPENREQUEST | XPC_C_ROPENREPLY |335 XPC_C_OPENREPLY | XPC_C_CONNECTED));336 337 /*338 * The meaningful OPENREQUEST connection state fields are:339 * entry_size = size of channel's messages in bytes340 * local_nentries = remote partition's local_nentries341 */342 if (args->entry_size == 0 || args->local_nentries == 0) {343 /* assume OPENREQUEST was delayed by mistake */344 goto out;345 }346 347 ch->flags |= (XPC_C_ROPENREQUEST | XPC_C_CONNECTING);348 ch->remote_nentries = args->local_nentries;349 350 if (ch->flags & XPC_C_OPENREQUEST) {351 if (args->entry_size != ch->entry_size) {352 XPC_DISCONNECT_CHANNEL(ch, xpUnequalMsgSizes,353 &irq_flags);354 goto out;355 }356 } else {357 ch->entry_size = args->entry_size;358 359 XPC_SET_REASON(ch, 0, 0);360 ch->flags &= ~XPC_C_DISCONNECTED;361 362 atomic_inc(&part->nchannels_active);363 }364 365 xpc_process_connect(ch, &irq_flags);366 }367 368 if (chctl_flags & XPC_CHCTL_OPENREPLY) {369 370 dev_dbg(xpc_chan, "XPC_CHCTL_OPENREPLY (local_msgqueue_pa="371 "0x%lx, local_nentries=%d, remote_nentries=%d) "372 "received from partid=%d, channel=%d\n",373 args->local_msgqueue_pa, args->local_nentries,374 args->remote_nentries, ch->partid, ch->number);375 376 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))377 goto out;378 379 if (!(ch->flags & XPC_C_OPENREQUEST)) {380 XPC_DISCONNECT_CHANNEL(ch, xpOpenCloseError,381 &irq_flags);382 goto out;383 }384 385 DBUG_ON(!(ch->flags & XPC_C_ROPENREQUEST));386 DBUG_ON(ch->flags & XPC_C_CONNECTED);387 388 /*389 * The meaningful OPENREPLY connection state fields are:390 * local_msgqueue_pa = physical address of remote391 * partition's local_msgqueue392 * local_nentries = remote partition's local_nentries393 * remote_nentries = remote partition's remote_nentries394 */395 DBUG_ON(args->local_msgqueue_pa == 0);396 DBUG_ON(args->local_nentries == 0);397 DBUG_ON(args->remote_nentries == 0);398 399 ret = xpc_arch_ops.save_remote_msgqueue_pa(ch,400 args->local_msgqueue_pa);401 if (ret != xpSuccess) {402 XPC_DISCONNECT_CHANNEL(ch, ret, &irq_flags);403 goto out;404 }405 ch->flags |= XPC_C_ROPENREPLY;406 407 if (args->local_nentries < ch->remote_nentries) {408 dev_dbg(xpc_chan, "XPC_CHCTL_OPENREPLY: new "409 "remote_nentries=%d, old remote_nentries=%d, "410 "partid=%d, channel=%d\n",411 args->local_nentries, ch->remote_nentries,412 ch->partid, ch->number);413 414 ch->remote_nentries = args->local_nentries;415 }416 if (args->remote_nentries < ch->local_nentries) {417 dev_dbg(xpc_chan, "XPC_CHCTL_OPENREPLY: new "418 "local_nentries=%d, old local_nentries=%d, "419 "partid=%d, channel=%d\n",420 args->remote_nentries, ch->local_nentries,421 ch->partid, ch->number);422 423 ch->local_nentries = args->remote_nentries;424 }425 426 xpc_process_connect(ch, &irq_flags);427 }428 429 if (chctl_flags & XPC_CHCTL_OPENCOMPLETE) {430 431 dev_dbg(xpc_chan, "XPC_CHCTL_OPENCOMPLETE received from "432 "partid=%d, channel=%d\n", ch->partid, ch->number);433 434 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))435 goto out;436 437 if (!(ch->flags & XPC_C_OPENREQUEST) ||438 !(ch->flags & XPC_C_OPENREPLY)) {439 XPC_DISCONNECT_CHANNEL(ch, xpOpenCloseError,440 &irq_flags);441 goto out;442 }443 444 DBUG_ON(!(ch->flags & XPC_C_ROPENREQUEST));445 DBUG_ON(!(ch->flags & XPC_C_ROPENREPLY));446 DBUG_ON(!(ch->flags & XPC_C_CONNECTED));447 448 ch->flags |= XPC_C_ROPENCOMPLETE;449 450 xpc_process_connect(ch, &irq_flags);451 create_kthread = 1;452 }453 454out:455 spin_unlock_irqrestore(&ch->lock, irq_flags);456 457 if (create_kthread)458 xpc_create_kthreads(ch, 1, 0);459}460 461/*462 * Attempt to establish a channel connection to a remote partition.463 */464static enum xp_retval465xpc_connect_channel(struct xpc_channel *ch)466{467 unsigned long irq_flags;468 struct xpc_registration *registration = &xpc_registrations[ch->number];469 470 if (mutex_trylock(®istration->mutex) == 0)471 return xpRetry;472 473 if (!XPC_CHANNEL_REGISTERED(ch->number)) {474 mutex_unlock(®istration->mutex);475 return xpUnregistered;476 }477 478 spin_lock_irqsave(&ch->lock, irq_flags);479 480 DBUG_ON(ch->flags & XPC_C_CONNECTED);481 DBUG_ON(ch->flags & XPC_C_OPENREQUEST);482 483 if (ch->flags & XPC_C_DISCONNECTING) {484 spin_unlock_irqrestore(&ch->lock, irq_flags);485 mutex_unlock(®istration->mutex);486 return ch->reason;487 }488 489 /* add info from the channel connect registration to the channel */490 491 ch->kthreads_assigned_limit = registration->assigned_limit;492 ch->kthreads_idle_limit = registration->idle_limit;493 DBUG_ON(atomic_read(&ch->kthreads_assigned) != 0);494 DBUG_ON(atomic_read(&ch->kthreads_idle) != 0);495 DBUG_ON(atomic_read(&ch->kthreads_active) != 0);496 497 ch->func = registration->func;498 DBUG_ON(registration->func == NULL);499 ch->key = registration->key;500 501 ch->local_nentries = registration->nentries;502 503 if (ch->flags & XPC_C_ROPENREQUEST) {504 if (registration->entry_size != ch->entry_size) {505 /* the local and remote sides aren't the same */506 507 /*508 * Because XPC_DISCONNECT_CHANNEL() can block we're509 * forced to up the registration sema before we unlock510 * the channel lock. But that's okay here because we're511 * done with the part that required the registration512 * sema. XPC_DISCONNECT_CHANNEL() requires that the513 * channel lock be locked and will unlock and relock514 * the channel lock as needed.515 */516 mutex_unlock(®istration->mutex);517 XPC_DISCONNECT_CHANNEL(ch, xpUnequalMsgSizes,518 &irq_flags);519 spin_unlock_irqrestore(&ch->lock, irq_flags);520 return xpUnequalMsgSizes;521 }522 } else {523 ch->entry_size = registration->entry_size;524 525 XPC_SET_REASON(ch, 0, 0);526 ch->flags &= ~XPC_C_DISCONNECTED;527 528 atomic_inc(&xpc_partitions[ch->partid].nchannels_active);529 }530 531 mutex_unlock(®istration->mutex);532 533 /* initiate the connection */534 535 ch->flags |= (XPC_C_OPENREQUEST | XPC_C_CONNECTING);536 xpc_arch_ops.send_chctl_openrequest(ch, &irq_flags);537 538 xpc_process_connect(ch, &irq_flags);539 540 spin_unlock_irqrestore(&ch->lock, irq_flags);541 542 return xpSuccess;543}544 545void546xpc_process_sent_chctl_flags(struct xpc_partition *part)547{548 unsigned long irq_flags;549 union xpc_channel_ctl_flags chctl;550 struct xpc_channel *ch;551 int ch_number;552 u32 ch_flags;553 554 chctl.all_flags = xpc_arch_ops.get_chctl_all_flags(part);555 556 /*557 * Initiate channel connections for registered channels.558 *559 * For each connected channel that has pending messages activate idle560 * kthreads and/or create new kthreads as needed.561 */562 563 for (ch_number = 0; ch_number < part->nchannels; ch_number++) {564 ch = &part->channels[ch_number];565 566 /*567 * Process any open or close related chctl flags, and then deal568 * with connecting or disconnecting the channel as required.569 */570 571 if (chctl.flags[ch_number] & XPC_OPENCLOSE_CHCTL_FLAGS) {572 xpc_process_openclose_chctl_flags(part, ch_number,573 chctl.flags[ch_number]);574 }575 576 ch_flags = ch->flags; /* need an atomic snapshot of flags */577 578 if (ch_flags & XPC_C_DISCONNECTING) {579 spin_lock_irqsave(&ch->lock, irq_flags);580 xpc_process_disconnect(ch, &irq_flags);581 spin_unlock_irqrestore(&ch->lock, irq_flags);582 continue;583 }584 585 if (part->act_state == XPC_P_AS_DEACTIVATING)586 continue;587 588 if (!(ch_flags & XPC_C_CONNECTED)) {589 if (!(ch_flags & XPC_C_OPENREQUEST)) {590 DBUG_ON(ch_flags & XPC_C_SETUP);591 (void)xpc_connect_channel(ch);592 }593 continue;594 }595 596 /*597 * Process any message related chctl flags, this may involve598 * the activation of kthreads to deliver any pending messages599 * sent from the other partition.600 */601 602 if (chctl.flags[ch_number] & XPC_MSG_CHCTL_FLAGS)603 xpc_arch_ops.process_msg_chctl_flags(part, ch_number);604 }605}606 607/*608 * XPC's heartbeat code calls this function to inform XPC that a partition is609 * going down. XPC responds by tearing down the XPartition Communication610 * infrastructure used for the just downed partition.611 *612 * XPC's heartbeat code will never call this function and xpc_partition_up()613 * at the same time. Nor will it ever make multiple calls to either function614 * at the same time.615 */616void617xpc_partition_going_down(struct xpc_partition *part, enum xp_retval reason)618{619 unsigned long irq_flags;620 int ch_number;621 struct xpc_channel *ch;622 623 dev_dbg(xpc_chan, "deactivating partition %d, reason=%d\n",624 XPC_PARTID(part), reason);625 626 if (!xpc_part_ref(part)) {627 /* infrastructure for this partition isn't currently set up */628 return;629 }630 631 /* disconnect channels associated with the partition going down */632 633 for (ch_number = 0; ch_number < part->nchannels; ch_number++) {634 ch = &part->channels[ch_number];635 636 xpc_msgqueue_ref(ch);637 spin_lock_irqsave(&ch->lock, irq_flags);638 639 XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags);640 641 spin_unlock_irqrestore(&ch->lock, irq_flags);642 xpc_msgqueue_deref(ch);643 }644 645 xpc_wakeup_channel_mgr(part);646 647 xpc_part_deref(part);648}649 650/*651 * Called by XP at the time of channel connection registration to cause652 * XPC to establish connections to all currently active partitions.653 */654void655xpc_initiate_connect(int ch_number)656{657 short partid;658 struct xpc_partition *part;659 660 DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);661 662 for (partid = 0; partid < xp_max_npartitions; partid++) {663 part = &xpc_partitions[partid];664 665 if (xpc_part_ref(part)) {666 /*667 * Initiate the establishment of a connection on the668 * newly registered channel to the remote partition.669 */670 xpc_wakeup_channel_mgr(part);671 xpc_part_deref(part);672 }673 }674}675 676void677xpc_connected_callout(struct xpc_channel *ch)678{679 /* let the registerer know that a connection has been established */680 681 if (ch->func != NULL) {682 dev_dbg(xpc_chan, "ch->func() called, reason=xpConnected, "683 "partid=%d, channel=%d\n", ch->partid, ch->number);684 685 ch->func(xpConnected, ch->partid, ch->number,686 (void *)(u64)ch->local_nentries, ch->key);687 688 dev_dbg(xpc_chan, "ch->func() returned, reason=xpConnected, "689 "partid=%d, channel=%d\n", ch->partid, ch->number);690 }691}692 693/*694 * Called by XP at the time of channel connection unregistration to cause695 * XPC to teardown all current connections for the specified channel.696 *697 * Before returning xpc_initiate_disconnect() will wait until all connections698 * on the specified channel have been closed/torndown. So the caller can be699 * assured that they will not be receiving any more callouts from XPC to the700 * function they registered via xpc_connect().701 *702 * Arguments:703 *704 * ch_number - channel # to unregister.705 */706void707xpc_initiate_disconnect(int ch_number)708{709 unsigned long irq_flags;710 short partid;711 struct xpc_partition *part;712 struct xpc_channel *ch;713 714 DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);715 716 /* initiate the channel disconnect for every active partition */717 for (partid = 0; partid < xp_max_npartitions; partid++) {718 part = &xpc_partitions[partid];719 720 if (xpc_part_ref(part)) {721 ch = &part->channels[ch_number];722 xpc_msgqueue_ref(ch);723 724 spin_lock_irqsave(&ch->lock, irq_flags);725 726 if (!(ch->flags & XPC_C_DISCONNECTED)) {727 ch->flags |= XPC_C_WDISCONNECT;728 729 XPC_DISCONNECT_CHANNEL(ch, xpUnregistering,730 &irq_flags);731 }732 733 spin_unlock_irqrestore(&ch->lock, irq_flags);734 735 xpc_msgqueue_deref(ch);736 xpc_part_deref(part);737 }738 }739 740 xpc_disconnect_wait(ch_number);741}742 743/*744 * To disconnect a channel, and reflect it back to all who may be waiting.745 *746 * An OPEN is not allowed until XPC_C_DISCONNECTING is cleared by747 * xpc_process_disconnect(), and if set, XPC_C_WDISCONNECT is cleared by748 * xpc_disconnect_wait().749 *750 * THE CHANNEL IS TO BE LOCKED BY THE CALLER AND WILL REMAIN LOCKED UPON RETURN.751 */752void753xpc_disconnect_channel(const int line, struct xpc_channel *ch,754 enum xp_retval reason, unsigned long *irq_flags)755{756 u32 channel_was_connected = (ch->flags & XPC_C_CONNECTED);757 758 lockdep_assert_held(&ch->lock);759 760 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))761 return;762 763 DBUG_ON(!(ch->flags & (XPC_C_CONNECTING | XPC_C_CONNECTED)));764 765 dev_dbg(xpc_chan, "reason=%d, line=%d, partid=%d, channel=%d\n",766 reason, line, ch->partid, ch->number);767 768 XPC_SET_REASON(ch, reason, line);769 770 ch->flags |= (XPC_C_CLOSEREQUEST | XPC_C_DISCONNECTING);771 /* some of these may not have been set */772 ch->flags &= ~(XPC_C_OPENREQUEST | XPC_C_OPENREPLY |773 XPC_C_ROPENREQUEST | XPC_C_ROPENREPLY |774 XPC_C_CONNECTING | XPC_C_CONNECTED);775 776 xpc_arch_ops.send_chctl_closerequest(ch, irq_flags);777 778 if (channel_was_connected)779 ch->flags |= XPC_C_WASCONNECTED;780 781 spin_unlock_irqrestore(&ch->lock, *irq_flags);782 783 /* wake all idle kthreads so they can exit */784 if (atomic_read(&ch->kthreads_idle) > 0) {785 wake_up_all(&ch->idle_wq);786 787 } else if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&788 !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {789 /* start a kthread that will do the xpDisconnecting callout */790 xpc_create_kthreads(ch, 1, 1);791 }792 793 /* wake those waiting to allocate an entry from the local msg queue */794 if (atomic_read(&ch->n_on_msg_allocate_wq) > 0)795 wake_up(&ch->msg_allocate_wq);796 797 spin_lock_irqsave(&ch->lock, *irq_flags);798}799 800void801xpc_disconnect_callout(struct xpc_channel *ch, enum xp_retval reason)802{803 /*804 * Let the channel's registerer know that the channel is being805 * disconnected. We don't want to do this if the registerer was never806 * informed of a connection being made.807 */808 809 if (ch->func != NULL) {810 dev_dbg(xpc_chan, "ch->func() called, reason=%d, partid=%d, "811 "channel=%d\n", reason, ch->partid, ch->number);812 813 ch->func(reason, ch->partid, ch->number, NULL, ch->key);814 815 dev_dbg(xpc_chan, "ch->func() returned, reason=%d, partid=%d, "816 "channel=%d\n", reason, ch->partid, ch->number);817 }818}819 820/*821 * Wait for a message entry to become available for the specified channel,822 * but don't wait any longer than 1 jiffy.823 */824enum xp_retval825xpc_allocate_msg_wait(struct xpc_channel *ch)826{827 enum xp_retval ret;828 DEFINE_WAIT(wait);829 830 if (ch->flags & XPC_C_DISCONNECTING) {831 DBUG_ON(ch->reason == xpInterrupted);832 return ch->reason;833 }834 835 atomic_inc(&ch->n_on_msg_allocate_wq);836 prepare_to_wait(&ch->msg_allocate_wq, &wait, TASK_INTERRUPTIBLE);837 ret = schedule_timeout(1);838 finish_wait(&ch->msg_allocate_wq, &wait);839 atomic_dec(&ch->n_on_msg_allocate_wq);840 841 if (ch->flags & XPC_C_DISCONNECTING) {842 ret = ch->reason;843 DBUG_ON(ch->reason == xpInterrupted);844 } else if (ret == 0) {845 ret = xpTimeout;846 } else {847 ret = xpInterrupted;848 }849 850 return ret;851}852 853/*854 * Send a message that contains the user's payload on the specified channel855 * connected to the specified partition.856 *857 * NOTE that this routine can sleep waiting for a message entry to become858 * available. To not sleep, pass in the XPC_NOWAIT flag.859 *860 * Once sent, this routine will not wait for the message to be received, nor861 * will notification be given when it does happen.862 *863 * Arguments:864 *865 * partid - ID of partition to which the channel is connected.866 * ch_number - channel # to send message on.867 * flags - see xp.h for valid flags.868 * payload - pointer to the payload which is to be sent.869 * payload_size - size of the payload in bytes.870 */871enum xp_retval872xpc_initiate_send(short partid, int ch_number, u32 flags, void *payload,873 u16 payload_size)874{875 struct xpc_partition *part = &xpc_partitions[partid];876 enum xp_retval ret = xpUnknownReason;877 878 dev_dbg(xpc_chan, "payload=0x%p, partid=%d, channel=%d\n", payload,879 partid, ch_number);880 881 DBUG_ON(partid < 0 || partid >= xp_max_npartitions);882 DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);883 DBUG_ON(payload == NULL);884 885 if (xpc_part_ref(part)) {886 ret = xpc_arch_ops.send_payload(&part->channels[ch_number],887 flags, payload, payload_size, 0, NULL, NULL);888 xpc_part_deref(part);889 }890 891 return ret;892}893 894/*895 * Send a message that contains the user's payload on the specified channel896 * connected to the specified partition.897 *898 * NOTE that this routine can sleep waiting for a message entry to become899 * available. To not sleep, pass in the XPC_NOWAIT flag.900 *901 * This routine will not wait for the message to be sent or received.902 *903 * Once the remote end of the channel has received the message, the function904 * passed as an argument to xpc_initiate_send_notify() will be called. This905 * allows the sender to free up or re-use any buffers referenced by the906 * message, but does NOT mean the message has been processed at the remote907 * end by a receiver.908 *909 * If this routine returns an error, the caller's function will NOT be called.910 *911 * Arguments:912 *913 * partid - ID of partition to which the channel is connected.914 * ch_number - channel # to send message on.915 * flags - see xp.h for valid flags.916 * payload - pointer to the payload which is to be sent.917 * payload_size - size of the payload in bytes.918 * func - function to call with asynchronous notification of message919 * receipt. THIS FUNCTION MUST BE NON-BLOCKING.920 * key - user-defined key to be passed to the function when it's called.921 */922enum xp_retval923xpc_initiate_send_notify(short partid, int ch_number, u32 flags, void *payload,924 u16 payload_size, xpc_notify_func func, void *key)925{926 struct xpc_partition *part = &xpc_partitions[partid];927 enum xp_retval ret = xpUnknownReason;928 929 dev_dbg(xpc_chan, "payload=0x%p, partid=%d, channel=%d\n", payload,930 partid, ch_number);931 932 DBUG_ON(partid < 0 || partid >= xp_max_npartitions);933 DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);934 DBUG_ON(payload == NULL);935 DBUG_ON(func == NULL);936 937 if (xpc_part_ref(part)) {938 ret = xpc_arch_ops.send_payload(&part->channels[ch_number],939 flags, payload, payload_size, XPC_N_CALL, func, key);940 xpc_part_deref(part);941 }942 return ret;943}944 945/*946 * Deliver a message's payload to its intended recipient.947 */948void949xpc_deliver_payload(struct xpc_channel *ch)950{951 void *payload;952 953 payload = xpc_arch_ops.get_deliverable_payload(ch);954 if (payload != NULL) {955 956 /*957 * This ref is taken to protect the payload itself from being958 * freed before the user is finished with it, which the user959 * indicates by calling xpc_initiate_received().960 */961 xpc_msgqueue_ref(ch);962 963 atomic_inc(&ch->kthreads_active);964 965 if (ch->func != NULL) {966 dev_dbg(xpc_chan, "ch->func() called, payload=0x%p "967 "partid=%d channel=%d\n", payload, ch->partid,968 ch->number);969 970 /* deliver the message to its intended recipient */971 ch->func(xpMsgReceived, ch->partid, ch->number, payload,972 ch->key);973 974 dev_dbg(xpc_chan, "ch->func() returned, payload=0x%p "975 "partid=%d channel=%d\n", payload, ch->partid,976 ch->number);977 }978 979 atomic_dec(&ch->kthreads_active);980 }981}982 983/*984 * Acknowledge receipt of a delivered message's payload.985 *986 * This function, although called by users, does not call xpc_part_ref() to987 * ensure that the partition infrastructure is in place. It relies on the988 * fact that we called xpc_msgqueue_ref() in xpc_deliver_payload().989 *990 * Arguments:991 *992 * partid - ID of partition to which the channel is connected.993 * ch_number - channel # message received on.994 * payload - pointer to the payload area allocated via995 * xpc_initiate_send() or xpc_initiate_send_notify().996 */997void998xpc_initiate_received(short partid, int ch_number, void *payload)999{1000 struct xpc_partition *part = &xpc_partitions[partid];1001 struct xpc_channel *ch;1002 1003 DBUG_ON(partid < 0 || partid >= xp_max_npartitions);1004 DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);1005 1006 ch = &part->channels[ch_number];1007 xpc_arch_ops.received_payload(ch, payload);1008 1009 /* the call to xpc_msgqueue_ref() was done by xpc_deliver_payload() */1010 xpc_msgqueue_deref(ch);1011}1012