Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / drivers / misc / sgi-xp / xpc_channel.c
blob128d5615c8040ce2c1225487cfc53f0d4d7fed97
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.
6 * Copyright (c) 2004-2009 Silicon Graphics, Inc. All Rights Reserved.
7 */
9 /*
10 * Cross Partition Communication (XPC) channel support.
12 * This is the part of XPC that manages the channels and
13 * sends/receives messages across them to/from other partitions.
17 #include <linux/device.h>
18 #include "xpc.h"
21 * Process a connect message from a remote partition.
23 * Note: xpc_process_connect() is expecting to be called with the
24 * spin_lock_irqsave held and will leave it locked upon return.
26 static void
27 xpc_process_connect(struct xpc_channel *ch, unsigned long *irq_flags)
29 enum xp_retval ret;
31 DBUG_ON(!spin_is_locked(&ch->lock));
33 if (!(ch->flags & XPC_C_OPENREQUEST) ||
34 !(ch->flags & XPC_C_ROPENREQUEST)) {
35 /* nothing more to do for now */
36 return;
38 DBUG_ON(!(ch->flags & XPC_C_CONNECTING));
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);
45 if (ret != xpSuccess)
46 XPC_DISCONNECT_CHANNEL(ch, ret, irq_flags);
47 else
48 ch->flags |= XPC_C_SETUP;
50 if (ch->flags & XPC_C_DISCONNECTING)
51 return;
54 if (!(ch->flags & XPC_C_OPENREPLY)) {
55 ch->flags |= XPC_C_OPENREPLY;
56 xpc_arch_ops.send_chctl_openreply(ch, irq_flags);
59 if (!(ch->flags & XPC_C_ROPENREPLY))
60 return;
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);
67 if (!(ch->flags & XPC_C_ROPENCOMPLETE))
68 return;
70 dev_info(xpc_chan, "channel %d to partition %d connected\n",
71 ch->number, ch->partid);
73 ch->flags = (XPC_C_CONNECTED | XPC_C_SETUP); /* clear all else */
77 * spin_lock_irqsave() is expected to be held on entry.
79 static void
80 xpc_process_disconnect(struct xpc_channel *ch, unsigned long *irq_flags)
82 struct xpc_partition *part = &xpc_partitions[ch->partid];
83 u32 channel_was_connected = (ch->flags & XPC_C_WASCONNECTED);
85 DBUG_ON(!spin_is_locked(&ch->lock));
87 if (!(ch->flags & XPC_C_DISCONNECTING))
88 return;
90 DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
92 /* make sure all activity has settled down first */
94 if (atomic_read(&ch->kthreads_assigned) > 0 ||
95 atomic_read(&ch->references) > 0) {
96 return;
98 DBUG_ON((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
99 !(ch->flags & XPC_C_DISCONNECTINGCALLOUT_MADE));
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;
106 } else {
108 /* as long as the other side is up do the full protocol */
110 if (!(ch->flags & XPC_C_RCLOSEREQUEST))
111 return;
113 if (!(ch->flags & XPC_C_CLOSEREPLY)) {
114 ch->flags |= XPC_C_CLOSEREPLY;
115 xpc_arch_ops.send_chctl_closereply(ch, irq_flags);
118 if (!(ch->flags & XPC_C_RCLOSEREPLY))
119 return;
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);
128 /* both sides are disconnected now */
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);
136 DBUG_ON(atomic_read(&ch->n_to_notify) != 0);
138 /* it's now safe to free the channel's message queues */
139 xpc_arch_ops.teardown_msg_structures(ch);
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;
150 * Mark the channel disconnected and clear all other flags, including
151 * XPC_C_SETUP (because of call to
152 * xpc_arch_ops.teardown_msg_structures()) but not including
153 * XPC_C_WDISCONNECT (if it was set).
155 ch->flags = (XPC_C_DISCONNECTED | (ch->flags & XPC_C_WDISCONNECT));
157 atomic_dec(&part->nchannels_active);
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);
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);
175 ch->delayed_chctl_flags = 0;
180 * Process a change in the channel's remote connection state.
182 static void
183 xpc_process_openclose_chctl_flags(struct xpc_partition *part, int ch_number,
184 u8 chctl_flags)
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;
194 spin_lock_irqsave(&ch->lock, irq_flags);
196 again:
198 if ((ch->flags & XPC_C_DISCONNECTED) &&
199 (ch->flags & XPC_C_WDISCONNECT)) {
201 * Delay processing chctl flags until thread waiting disconnect
202 * has had a chance to see that the channel is disconnected.
204 ch->delayed_chctl_flags |= chctl_flags;
205 goto out;
208 if (chctl_flags & XPC_CHCTL_CLOSEREQUEST) {
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);
215 * If RCLOSEREQUEST is set, we're probably waiting for
216 * RCLOSEREPLY. We should find it and a ROPENREQUEST packed
217 * with this RCLOSEREQUEST in the chctl_flags.
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);
226 DBUG_ON(!(chctl_flags & XPC_CHCTL_CLOSEREPLY));
227 chctl_flags &= ~XPC_CHCTL_CLOSEREPLY;
228 ch->flags |= XPC_C_RCLOSEREPLY;
230 /* both sides have finished disconnecting */
231 xpc_process_disconnect(ch, &irq_flags);
232 DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
233 goto again;
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) {
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);
247 goto out;
250 XPC_SET_REASON(ch, 0, 0);
251 ch->flags &= ~XPC_C_DISCONNECTED;
253 atomic_inc(&part->nchannels_active);
254 ch->flags |= (XPC_C_CONNECTING | XPC_C_ROPENREQUEST);
257 chctl_flags &= ~(XPC_CHCTL_OPENREQUEST | XPC_CHCTL_OPENREPLY |
258 XPC_CHCTL_OPENCOMPLETE);
261 * The meaningful CLOSEREQUEST connection state fields are:
262 * reason = reason connection is to be closed
265 ch->flags |= XPC_C_RCLOSEREQUEST;
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;
274 XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags);
276 DBUG_ON(chctl_flags & XPC_CHCTL_CLOSEREPLY);
277 goto out;
280 xpc_process_disconnect(ch, &irq_flags);
283 if (chctl_flags & XPC_CHCTL_CLOSEREPLY) {
285 dev_dbg(xpc_chan, "XPC_CHCTL_CLOSEREPLY received from partid="
286 "%d, channel=%d\n", ch->partid, ch->number);
288 if (ch->flags & XPC_C_DISCONNECTED) {
289 DBUG_ON(part->act_state != XPC_P_AS_DEACTIVATING);
290 goto out;
293 DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
295 if (!(ch->flags & XPC_C_RCLOSEREQUEST)) {
296 if (part->chctl.flags[ch_number] &
297 XPC_CHCTL_CLOSEREQUEST) {
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);
305 goto out;
308 ch->flags |= XPC_C_RCLOSEREPLY;
310 if (ch->flags & XPC_C_CLOSEREPLY) {
311 /* both sides have finished disconnecting */
312 xpc_process_disconnect(ch, &irq_flags);
316 if (chctl_flags & XPC_CHCTL_OPENREQUEST) {
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);
323 if (part->act_state == XPC_P_AS_DEACTIVATING ||
324 (ch->flags & XPC_C_ROPENREQUEST)) {
325 goto out;
328 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_WDISCONNECT)) {
329 ch->delayed_chctl_flags |= XPC_CHCTL_OPENREQUEST;
330 goto out;
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));
338 * The meaningful OPENREQUEST connection state fields are:
339 * entry_size = size of channel's messages in bytes
340 * local_nentries = remote partition's local_nentries
342 if (args->entry_size == 0 || args->local_nentries == 0) {
343 /* assume OPENREQUEST was delayed by mistake */
344 goto out;
347 ch->flags |= (XPC_C_ROPENREQUEST | XPC_C_CONNECTING);
348 ch->remote_nentries = args->local_nentries;
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;
356 } else {
357 ch->entry_size = args->entry_size;
359 XPC_SET_REASON(ch, 0, 0);
360 ch->flags &= ~XPC_C_DISCONNECTED;
362 atomic_inc(&part->nchannels_active);
365 xpc_process_connect(ch, &irq_flags);
368 if (chctl_flags & XPC_CHCTL_OPENREPLY) {
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);
376 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))
377 goto out;
379 if (!(ch->flags & XPC_C_OPENREQUEST)) {
380 XPC_DISCONNECT_CHANNEL(ch, xpOpenCloseError,
381 &irq_flags);
382 goto out;
385 DBUG_ON(!(ch->flags & XPC_C_ROPENREQUEST));
386 DBUG_ON(ch->flags & XPC_C_CONNECTED);
389 * The meaningful OPENREPLY connection state fields are:
390 * local_msgqueue_pa = physical address of remote
391 * partition's local_msgqueue
392 * local_nentries = remote partition's local_nentries
393 * remote_nentries = remote partition's remote_nentries
395 DBUG_ON(args->local_msgqueue_pa == 0);
396 DBUG_ON(args->local_nentries == 0);
397 DBUG_ON(args->remote_nentries == 0);
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;
405 ch->flags |= XPC_C_ROPENREPLY;
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);
414 ch->remote_nentries = args->local_nentries;
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);
423 ch->local_nentries = args->remote_nentries;
426 xpc_process_connect(ch, &irq_flags);
429 if (chctl_flags & XPC_CHCTL_OPENCOMPLETE) {
431 dev_dbg(xpc_chan, "XPC_CHCTL_OPENCOMPLETE received from "
432 "partid=%d, channel=%d\n", ch->partid, ch->number);
434 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))
435 goto out;
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;
444 DBUG_ON(!(ch->flags & XPC_C_ROPENREQUEST));
445 DBUG_ON(!(ch->flags & XPC_C_ROPENREPLY));
446 DBUG_ON(!(ch->flags & XPC_C_CONNECTED));
448 ch->flags |= XPC_C_ROPENCOMPLETE;
450 xpc_process_connect(ch, &irq_flags);
451 create_kthread = 1;
454 out:
455 spin_unlock_irqrestore(&ch->lock, irq_flags);
457 if (create_kthread)
458 xpc_create_kthreads(ch, 1, 0);
462 * Attempt to establish a channel connection to a remote partition.
464 static enum xp_retval
465 xpc_connect_channel(struct xpc_channel *ch)
467 unsigned long irq_flags;
468 struct xpc_registration *registration = &xpc_registrations[ch->number];
470 if (mutex_trylock(&registration->mutex) == 0)
471 return xpRetry;
473 if (!XPC_CHANNEL_REGISTERED(ch->number)) {
474 mutex_unlock(&registration->mutex);
475 return xpUnregistered;
478 spin_lock_irqsave(&ch->lock, irq_flags);
480 DBUG_ON(ch->flags & XPC_C_CONNECTED);
481 DBUG_ON(ch->flags & XPC_C_OPENREQUEST);
483 if (ch->flags & XPC_C_DISCONNECTING) {
484 spin_unlock_irqrestore(&ch->lock, irq_flags);
485 mutex_unlock(&registration->mutex);
486 return ch->reason;
489 /* add info from the channel connect registration to the channel */
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);
497 ch->func = registration->func;
498 DBUG_ON(registration->func == NULL);
499 ch->key = registration->key;
501 ch->local_nentries = registration->nentries;
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 */
508 * Because XPC_DISCONNECT_CHANNEL() can block we're
509 * forced to up the registration sema before we unlock
510 * the channel lock. But that's okay here because we're
511 * done with the part that required the registration
512 * sema. XPC_DISCONNECT_CHANNEL() requires that the
513 * channel lock be locked and will unlock and relock
514 * the channel lock as needed.
516 mutex_unlock(&registration->mutex);
517 XPC_DISCONNECT_CHANNEL(ch, xpUnequalMsgSizes,
518 &irq_flags);
519 spin_unlock_irqrestore(&ch->lock, irq_flags);
520 return xpUnequalMsgSizes;
522 } else {
523 ch->entry_size = registration->entry_size;
525 XPC_SET_REASON(ch, 0, 0);
526 ch->flags &= ~XPC_C_DISCONNECTED;
528 atomic_inc(&xpc_partitions[ch->partid].nchannels_active);
531 mutex_unlock(&registration->mutex);
533 /* initiate the connection */
535 ch->flags |= (XPC_C_OPENREQUEST | XPC_C_CONNECTING);
536 xpc_arch_ops.send_chctl_openrequest(ch, &irq_flags);
538 xpc_process_connect(ch, &irq_flags);
540 spin_unlock_irqrestore(&ch->lock, irq_flags);
542 return xpSuccess;
545 void
546 xpc_process_sent_chctl_flags(struct xpc_partition *part)
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;
554 chctl.all_flags = xpc_arch_ops.get_chctl_all_flags(part);
557 * Initiate channel connections for registered channels.
559 * For each connected channel that has pending messages activate idle
560 * kthreads and/or create new kthreads as needed.
563 for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
564 ch = &part->channels[ch_number];
567 * Process any open or close related chctl flags, and then deal
568 * with connecting or disconnecting the channel as required.
571 if (chctl.flags[ch_number] & XPC_OPENCLOSE_CHCTL_FLAGS) {
572 xpc_process_openclose_chctl_flags(part, ch_number,
573 chctl.flags[ch_number]);
576 ch_flags = ch->flags; /* need an atomic snapshot of flags */
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;
585 if (part->act_state == XPC_P_AS_DEACTIVATING)
586 continue;
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);
593 continue;
597 * Process any message related chctl flags, this may involve
598 * the activation of kthreads to deliver any pending messages
599 * sent from the other partition.
602 if (chctl.flags[ch_number] & XPC_MSG_CHCTL_FLAGS)
603 xpc_arch_ops.process_msg_chctl_flags(part, ch_number);
608 * XPC's heartbeat code calls this function to inform XPC that a partition is
609 * going down. XPC responds by tearing down the XPartition Communication
610 * infrastructure used for the just downed partition.
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 function
614 * at the same time.
616 void
617 xpc_partition_going_down(struct xpc_partition *part, enum xp_retval reason)
619 unsigned long irq_flags;
620 int ch_number;
621 struct xpc_channel *ch;
623 dev_dbg(xpc_chan, "deactivating partition %d, reason=%d\n",
624 XPC_PARTID(part), reason);
626 if (!xpc_part_ref(part)) {
627 /* infrastructure for this partition isn't currently set up */
628 return;
631 /* disconnect channels associated with the partition going down */
633 for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
634 ch = &part->channels[ch_number];
636 xpc_msgqueue_ref(ch);
637 spin_lock_irqsave(&ch->lock, irq_flags);
639 XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags);
641 spin_unlock_irqrestore(&ch->lock, irq_flags);
642 xpc_msgqueue_deref(ch);
645 xpc_wakeup_channel_mgr(part);
647 xpc_part_deref(part);
651 * Called by XP at the time of channel connection registration to cause
652 * XPC to establish connections to all currently active partitions.
654 void
655 xpc_initiate_connect(int ch_number)
657 short partid;
658 struct xpc_partition *part;
659 struct xpc_channel *ch;
661 DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
663 for (partid = 0; partid < xp_max_npartitions; partid++) {
664 part = &xpc_partitions[partid];
666 if (xpc_part_ref(part)) {
667 ch = &part->channels[ch_number];
670 * Initiate the establishment of a connection on the
671 * newly registered channel to the remote partition.
673 xpc_wakeup_channel_mgr(part);
674 xpc_part_deref(part);
679 void
680 xpc_connected_callout(struct xpc_channel *ch)
682 /* let the registerer know that a connection has been established */
684 if (ch->func != NULL) {
685 dev_dbg(xpc_chan, "ch->func() called, reason=xpConnected, "
686 "partid=%d, channel=%d\n", ch->partid, ch->number);
688 ch->func(xpConnected, ch->partid, ch->number,
689 (void *)(u64)ch->local_nentries, ch->key);
691 dev_dbg(xpc_chan, "ch->func() returned, reason=xpConnected, "
692 "partid=%d, channel=%d\n", ch->partid, ch->number);
697 * Called by XP at the time of channel connection unregistration to cause
698 * XPC to teardown all current connections for the specified channel.
700 * Before returning xpc_initiate_disconnect() will wait until all connections
701 * on the specified channel have been closed/torndown. So the caller can be
702 * assured that they will not be receiving any more callouts from XPC to the
703 * function they registered via xpc_connect().
705 * Arguments:
707 * ch_number - channel # to unregister.
709 void
710 xpc_initiate_disconnect(int ch_number)
712 unsigned long irq_flags;
713 short partid;
714 struct xpc_partition *part;
715 struct xpc_channel *ch;
717 DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
719 /* initiate the channel disconnect for every active partition */
720 for (partid = 0; partid < xp_max_npartitions; partid++) {
721 part = &xpc_partitions[partid];
723 if (xpc_part_ref(part)) {
724 ch = &part->channels[ch_number];
725 xpc_msgqueue_ref(ch);
727 spin_lock_irqsave(&ch->lock, irq_flags);
729 if (!(ch->flags & XPC_C_DISCONNECTED)) {
730 ch->flags |= XPC_C_WDISCONNECT;
732 XPC_DISCONNECT_CHANNEL(ch, xpUnregistering,
733 &irq_flags);
736 spin_unlock_irqrestore(&ch->lock, irq_flags);
738 xpc_msgqueue_deref(ch);
739 xpc_part_deref(part);
743 xpc_disconnect_wait(ch_number);
747 * To disconnect a channel, and reflect it back to all who may be waiting.
749 * An OPEN is not allowed until XPC_C_DISCONNECTING is cleared by
750 * xpc_process_disconnect(), and if set, XPC_C_WDISCONNECT is cleared by
751 * xpc_disconnect_wait().
753 * THE CHANNEL IS TO BE LOCKED BY THE CALLER AND WILL REMAIN LOCKED UPON RETURN.
755 void
756 xpc_disconnect_channel(const int line, struct xpc_channel *ch,
757 enum xp_retval reason, unsigned long *irq_flags)
759 u32 channel_was_connected = (ch->flags & XPC_C_CONNECTED);
761 DBUG_ON(!spin_is_locked(&ch->lock));
763 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))
764 return;
766 DBUG_ON(!(ch->flags & (XPC_C_CONNECTING | XPC_C_CONNECTED)));
768 dev_dbg(xpc_chan, "reason=%d, line=%d, partid=%d, channel=%d\n",
769 reason, line, ch->partid, ch->number);
771 XPC_SET_REASON(ch, reason, line);
773 ch->flags |= (XPC_C_CLOSEREQUEST | XPC_C_DISCONNECTING);
774 /* some of these may not have been set */
775 ch->flags &= ~(XPC_C_OPENREQUEST | XPC_C_OPENREPLY |
776 XPC_C_ROPENREQUEST | XPC_C_ROPENREPLY |
777 XPC_C_CONNECTING | XPC_C_CONNECTED);
779 xpc_arch_ops.send_chctl_closerequest(ch, irq_flags);
781 if (channel_was_connected)
782 ch->flags |= XPC_C_WASCONNECTED;
784 spin_unlock_irqrestore(&ch->lock, *irq_flags);
786 /* wake all idle kthreads so they can exit */
787 if (atomic_read(&ch->kthreads_idle) > 0) {
788 wake_up_all(&ch->idle_wq);
790 } else if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
791 !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
792 /* start a kthread that will do the xpDisconnecting callout */
793 xpc_create_kthreads(ch, 1, 1);
796 /* wake those waiting to allocate an entry from the local msg queue */
797 if (atomic_read(&ch->n_on_msg_allocate_wq) > 0)
798 wake_up(&ch->msg_allocate_wq);
800 spin_lock_irqsave(&ch->lock, *irq_flags);
803 void
804 xpc_disconnect_callout(struct xpc_channel *ch, enum xp_retval reason)
807 * Let the channel's registerer know that the channel is being
808 * disconnected. We don't want to do this if the registerer was never
809 * informed of a connection being made.
812 if (ch->func != NULL) {
813 dev_dbg(xpc_chan, "ch->func() called, reason=%d, partid=%d, "
814 "channel=%d\n", reason, ch->partid, ch->number);
816 ch->func(reason, ch->partid, ch->number, NULL, ch->key);
818 dev_dbg(xpc_chan, "ch->func() returned, reason=%d, partid=%d, "
819 "channel=%d\n", reason, ch->partid, ch->number);
824 * Wait for a message entry to become available for the specified channel,
825 * but don't wait any longer than 1 jiffy.
827 enum xp_retval
828 xpc_allocate_msg_wait(struct xpc_channel *ch)
830 enum xp_retval ret;
831 DEFINE_WAIT(wait);
833 if (ch->flags & XPC_C_DISCONNECTING) {
834 DBUG_ON(ch->reason == xpInterrupted);
835 return ch->reason;
838 atomic_inc(&ch->n_on_msg_allocate_wq);
839 prepare_to_wait(&ch->msg_allocate_wq, &wait, TASK_INTERRUPTIBLE);
840 ret = schedule_timeout(1);
841 finish_wait(&ch->msg_allocate_wq, &wait);
842 atomic_dec(&ch->n_on_msg_allocate_wq);
844 if (ch->flags & XPC_C_DISCONNECTING) {
845 ret = ch->reason;
846 DBUG_ON(ch->reason == xpInterrupted);
847 } else if (ret == 0) {
848 ret = xpTimeout;
849 } else {
850 ret = xpInterrupted;
853 return ret;
857 * Send a message that contains the user's payload on the specified channel
858 * connected to the specified partition.
860 * NOTE that this routine can sleep waiting for a message entry to become
861 * available. To not sleep, pass in the XPC_NOWAIT flag.
863 * Once sent, this routine will not wait for the message to be received, nor
864 * will notification be given when it does happen.
866 * Arguments:
868 * partid - ID of partition to which the channel is connected.
869 * ch_number - channel # to send message on.
870 * flags - see xp.h for valid flags.
871 * payload - pointer to the payload which is to be sent.
872 * payload_size - size of the payload in bytes.
874 enum xp_retval
875 xpc_initiate_send(short partid, int ch_number, u32 flags, void *payload,
876 u16 payload_size)
878 struct xpc_partition *part = &xpc_partitions[partid];
879 enum xp_retval ret = xpUnknownReason;
881 dev_dbg(xpc_chan, "payload=0x%p, partid=%d, channel=%d\n", payload,
882 partid, ch_number);
884 DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
885 DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
886 DBUG_ON(payload == NULL);
888 if (xpc_part_ref(part)) {
889 ret = xpc_arch_ops.send_payload(&part->channels[ch_number],
890 flags, payload, payload_size, 0, NULL, NULL);
891 xpc_part_deref(part);
894 return ret;
898 * Send a message that contains the user's payload on the specified channel
899 * connected to the specified partition.
901 * NOTE that this routine can sleep waiting for a message entry to become
902 * available. To not sleep, pass in the XPC_NOWAIT flag.
904 * This routine will not wait for the message to be sent or received.
906 * Once the remote end of the channel has received the message, the function
907 * passed as an argument to xpc_initiate_send_notify() will be called. This
908 * allows the sender to free up or re-use any buffers referenced by the
909 * message, but does NOT mean the message has been processed at the remote
910 * end by a receiver.
912 * If this routine returns an error, the caller's function will NOT be called.
914 * Arguments:
916 * partid - ID of partition to which the channel is connected.
917 * ch_number - channel # to send message on.
918 * flags - see xp.h for valid flags.
919 * payload - pointer to the payload which is to be sent.
920 * payload_size - size of the payload in bytes.
921 * func - function to call with asynchronous notification of message
922 * receipt. THIS FUNCTION MUST BE NON-BLOCKING.
923 * key - user-defined key to be passed to the function when it's called.
925 enum xp_retval
926 xpc_initiate_send_notify(short partid, int ch_number, u32 flags, void *payload,
927 u16 payload_size, xpc_notify_func func, void *key)
929 struct xpc_partition *part = &xpc_partitions[partid];
930 enum xp_retval ret = xpUnknownReason;
932 dev_dbg(xpc_chan, "payload=0x%p, partid=%d, channel=%d\n", payload,
933 partid, ch_number);
935 DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
936 DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
937 DBUG_ON(payload == NULL);
938 DBUG_ON(func == NULL);
940 if (xpc_part_ref(part)) {
941 ret = xpc_arch_ops.send_payload(&part->channels[ch_number],
942 flags, payload, payload_size, XPC_N_CALL, func, key);
943 xpc_part_deref(part);
945 return ret;
949 * Deliver a message's payload to its intended recipient.
951 void
952 xpc_deliver_payload(struct xpc_channel *ch)
954 void *payload;
956 payload = xpc_arch_ops.get_deliverable_payload(ch);
957 if (payload != NULL) {
960 * This ref is taken to protect the payload itself from being
961 * freed before the user is finished with it, which the user
962 * indicates by calling xpc_initiate_received().
964 xpc_msgqueue_ref(ch);
966 atomic_inc(&ch->kthreads_active);
968 if (ch->func != NULL) {
969 dev_dbg(xpc_chan, "ch->func() called, payload=0x%p "
970 "partid=%d channel=%d\n", payload, ch->partid,
971 ch->number);
973 /* deliver the message to its intended recipient */
974 ch->func(xpMsgReceived, ch->partid, ch->number, payload,
975 ch->key);
977 dev_dbg(xpc_chan, "ch->func() returned, payload=0x%p "
978 "partid=%d channel=%d\n", payload, ch->partid,
979 ch->number);
982 atomic_dec(&ch->kthreads_active);
987 * Acknowledge receipt of a delivered message's payload.
989 * This function, although called by users, does not call xpc_part_ref() to
990 * ensure that the partition infrastructure is in place. It relies on the
991 * fact that we called xpc_msgqueue_ref() in xpc_deliver_payload().
993 * Arguments:
995 * partid - ID of partition to which the channel is connected.
996 * ch_number - channel # message received on.
997 * payload - pointer to the payload area allocated via
998 * xpc_initiate_send() or xpc_initiate_send_notify().
1000 void
1001 xpc_initiate_received(short partid, int ch_number, void *payload)
1003 struct xpc_partition *part = &xpc_partitions[partid];
1004 struct xpc_channel *ch;
1006 DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
1007 DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
1009 ch = &part->channels[ch_number];
1010 xpc_arch_ops.received_payload(ch, payload);
1012 /* the call to xpc_msgqueue_ref() was done by xpc_deliver_payload() */
1013 xpc_msgqueue_deref(ch);