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) 2004-2009 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 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
xpc_process_connect(struct xpc_channel * ch,unsigned long * irq_flags)27 xpc_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 else
48 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 */
79 static void
xpc_process_disconnect(struct xpc_channel * ch,unsigned long * irq_flags)80 xpc_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, 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).
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 */
182 static void
xpc_process_openclose_chctl_flags(struct xpc_partition * part,int ch_number,u8 chctl_flags)183 xpc_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
196 again:
197
198 if ((ch->flags & XPC_C_DISCONNECTED) &&
199 (ch->flags & XPC_C_WDISCONNECT)) {
200 /*
201 * Delay processing chctl flags until thread waiting disconnect
202 * 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 for
216 * RCLOSEREPLY. We should find it and a ROPENREQUEST packed
217 * 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 closed
263 */
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 bytes
340 * local_nentries = remote partition's local_nentries
341 */
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 remote
391 * partition's local_msgqueue
392 * local_nentries = remote partition's local_nentries
393 * remote_nentries = remote partition's remote_nentries
394 */
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
454 out:
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 */
464 static enum xp_retval
xpc_connect_channel(struct xpc_channel * ch)465 xpc_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'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.
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
545 void
xpc_process_sent_chctl_flags(struct xpc_partition * part)546 xpc_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 idle
560 * 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 deal
568 * 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 involve
598 * the activation of kthreads to deliver any pending messages
599 * 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 is
609 * going down. XPC responds by tearing down the XPartition Communication
610 * 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 function
614 * at the same time.
615 */
616 void
xpc_partition_going_down(struct xpc_partition * part,enum xp_retval reason)617 xpc_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 cause
652 * XPC to establish connections to all currently active partitions.
653 */
654 void
xpc_initiate_connect(int ch_number)655 xpc_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 the
668 * newly registered channel to the remote partition.
669 */
670 xpc_wakeup_channel_mgr(part);
671 xpc_part_deref(part);
672 }
673 }
674 }
675
676 void
xpc_connected_callout(struct xpc_channel * ch)677 xpc_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 cause
695 * XPC to teardown all current connections for the specified channel.
696 *
697 * Before returning xpc_initiate_disconnect() will wait until all connections
698 * on the specified channel have been closed/torndown. So the caller can be
699 * assured that they will not be receiving any more callouts from XPC to the
700 * function they registered via xpc_connect().
701 *
702 * Arguments:
703 *
704 * ch_number - channel # to unregister.
705 */
706 void
xpc_initiate_disconnect(int ch_number)707 xpc_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 by
747 * xpc_process_disconnect(), and if set, XPC_C_WDISCONNECT is cleared by
748 * xpc_disconnect_wait().
749 *
750 * THE CHANNEL IS TO BE LOCKED BY THE CALLER AND WILL REMAIN LOCKED UPON RETURN.
751 */
752 void
xpc_disconnect_channel(const int line,struct xpc_channel * ch,enum xp_retval reason,unsigned long * irq_flags)753 xpc_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
800 void
xpc_disconnect_callout(struct xpc_channel * ch,enum xp_retval reason)801 xpc_disconnect_callout(struct xpc_channel *ch, enum xp_retval reason)
802 {
803 /*
804 * Let the channel's registerer know that the channel is being
805 * disconnected. We don't want to do this if the registerer was never
806 * 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 */
824 enum xp_retval
xpc_allocate_msg_wait(struct xpc_channel * ch)825 xpc_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 channel
855 * connected to the specified partition.
856 *
857 * NOTE that this routine can sleep waiting for a message entry to become
858 * 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, nor
861 * 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 */
871 enum xp_retval
xpc_initiate_send(short partid,int ch_number,u32 flags,void * payload,u16 payload_size)872 xpc_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 channel
896 * connected to the specified partition.
897 *
898 * NOTE that this routine can sleep waiting for a message entry to become
899 * 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 function
904 * passed as an argument to xpc_initiate_send_notify() will be called. This
905 * allows the sender to free up or re-use any buffers referenced by the
906 * message, but does NOT mean the message has been processed at the remote
907 * 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 message
919 * receipt. THIS FUNCTION MUST BE NON-BLOCKING.
920 * key - user-defined key to be passed to the function when it's called.
921 */
922 enum xp_retval
xpc_initiate_send_notify(short partid,int ch_number,u32 flags,void * payload,u16 payload_size,xpc_notify_func func,void * key)923 xpc_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 */
948 void
xpc_deliver_payload(struct xpc_channel * ch)949 xpc_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 being
958 * freed before the user is finished with it, which the user
959 * 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() to
987 * ensure that the partition infrastructure is in place. It relies on the
988 * 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 via
995 * xpc_initiate_send() or xpc_initiate_send_notify().
996 */
997 void
xpc_initiate_received(short partid,int ch_number,void * payload)998 xpc_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