summaryrefslogtreecommitdiffstats
path: root/sys/geom/gate/g_gate.c
blob: 22338a513caaa7b10de5806ad8d205c5cd7eb394 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
/*-
 * Copyright (c) 2004-2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
 * Copyright (c) 2009-2010 The FreeBSD Foundation
 * All rights reserved.
 *
 * Portions of this software were developed by Pawel Jakub Dawidek
 * under sponsorship from the FreeBSD Foundation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/fcntl.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/limits.h>
#include <sys/queue.h>
#include <sys/sysctl.h>
#include <sys/signalvar.h>
#include <sys/time.h>
#include <machine/atomic.h>

#include <geom/geom.h>
#include <geom/gate/g_gate.h>

FEATURE(geom_gate, "GEOM Gate module");

static MALLOC_DEFINE(M_GATE, "gg_data", "GEOM Gate Data");

SYSCTL_DECL(_kern_geom);
SYSCTL_NODE(_kern_geom, OID_AUTO, gate, CTLFLAG_RW, 0, "GEOM_GATE stuff");
static int g_gate_debug = 0;
TUNABLE_INT("kern.geom.gate.debug", &g_gate_debug);
SYSCTL_INT(_kern_geom_gate, OID_AUTO, debug, CTLFLAG_RW, &g_gate_debug, 0,
    "Debug level");
static u_int g_gate_maxunits = 256;
TUNABLE_INT("kern.geom.gate.maxunits", &g_gate_maxunits);
SYSCTL_UINT(_kern_geom_gate, OID_AUTO, maxunits, CTLFLAG_RDTUN,
    &g_gate_maxunits, 0, "Maximum number of ggate devices");

struct g_class g_gate_class = {
	.name = G_GATE_CLASS_NAME,
	.version = G_VERSION,
};

static struct cdev *status_dev;
static d_ioctl_t g_gate_ioctl;
static struct cdevsw g_gate_cdevsw = {
	.d_version =	D_VERSION,
	.d_ioctl =	g_gate_ioctl,
	.d_name =	G_GATE_CTL_NAME
};


static struct g_gate_softc **g_gate_units;
static u_int g_gate_nunits;
static struct mtx g_gate_units_lock;

static int
g_gate_destroy(struct g_gate_softc *sc, boolean_t force)
{
	struct g_provider *pp;
	struct g_geom *gp;
	struct bio *bp;

	g_topology_assert();
	mtx_assert(&g_gate_units_lock, MA_OWNED);
	pp = sc->sc_provider;
	if (!force && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
		mtx_unlock(&g_gate_units_lock);
		return (EBUSY);
	}
	mtx_unlock(&g_gate_units_lock);
	mtx_lock(&sc->sc_queue_mtx);
	if ((sc->sc_flags & G_GATE_FLAG_DESTROY) == 0)
		sc->sc_flags |= G_GATE_FLAG_DESTROY;
	wakeup(sc);
	mtx_unlock(&sc->sc_queue_mtx);
	gp = pp->geom;
	pp->flags |= G_PF_WITHER;
	g_orphan_provider(pp, ENXIO);
	callout_drain(&sc->sc_callout);
	mtx_lock(&sc->sc_queue_mtx);
	while ((bp = bioq_first(&sc->sc_inqueue)) != NULL) {
		bioq_remove(&sc->sc_inqueue, bp);
		sc->sc_queue_count--;
		G_GATE_LOGREQ(1, bp, "Request canceled.");
		g_io_deliver(bp, ENXIO);
	}
	while ((bp = bioq_first(&sc->sc_outqueue)) != NULL) {
		bioq_remove(&sc->sc_outqueue, bp);
		sc->sc_queue_count--;
		G_GATE_LOGREQ(1, bp, "Request canceled.");
		g_io_deliver(bp, ENXIO);
	}
	mtx_unlock(&sc->sc_queue_mtx);
	g_topology_unlock();
	mtx_lock(&g_gate_units_lock);
	/* One reference is ours. */
	sc->sc_ref--;
	while (sc->sc_ref > 0)
		msleep(&sc->sc_ref, &g_gate_units_lock, 0, "gg:destroy", 0);
	g_gate_units[sc->sc_unit] = NULL;
	KASSERT(g_gate_nunits > 0, ("negative g_gate_nunits?"));
	g_gate_nunits--;
	mtx_unlock(&g_gate_units_lock);
	mtx_destroy(&sc->sc_queue_mtx);
	g_topology_lock();
	G_GATE_DEBUG(1, "Device %s destroyed.", gp->name);
	gp->softc = NULL;
	g_wither_geom(gp, ENXIO);
	sc->sc_provider = NULL;
	free(sc, M_GATE);
	return (0);
}

static int
g_gate_access(struct g_provider *pp, int dr, int dw, int de)
{
	struct g_gate_softc *sc;

	if (dr <= 0 && dw <= 0 && de <= 0)
		return (0);
	sc = pp->geom->softc;
	if (sc == NULL || (sc->sc_flags & G_GATE_FLAG_DESTROY) != 0)
		return (ENXIO);
	/* XXX: Hack to allow read-only mounts. */
#if 0
	if ((sc->sc_flags & G_GATE_FLAG_READONLY) != 0 && dw > 0)
		return (EPERM);
#endif
	if ((sc->sc_flags & G_GATE_FLAG_WRITEONLY) != 0 && dr > 0)
		return (EPERM);
	return (0);
}

static void
g_gate_start(struct bio *bp)
{
	struct g_gate_softc *sc;

	sc = bp->bio_to->geom->softc;
	if (sc == NULL || (sc->sc_flags & G_GATE_FLAG_DESTROY) != 0) {
		g_io_deliver(bp, ENXIO);
		return;
	}
	G_GATE_LOGREQ(2, bp, "Request received.");
	switch (bp->bio_cmd) {
	case BIO_READ:
		break;
	case BIO_DELETE:
	case BIO_WRITE:
	case BIO_FLUSH:
		/* XXX: Hack to allow read-only mounts. */
		if ((sc->sc_flags & G_GATE_FLAG_READONLY) != 0) {
			g_io_deliver(bp, EPERM);
			return;
		}
		break;
	case BIO_GETATTR:
	default:
		G_GATE_LOGREQ(2, bp, "Ignoring request.");
		g_io_deliver(bp, EOPNOTSUPP);
		return;
	}

	mtx_lock(&sc->sc_queue_mtx);
	if (sc->sc_queue_size > 0 && sc->sc_queue_count > sc->sc_queue_size) {
		mtx_unlock(&sc->sc_queue_mtx);
		G_GATE_LOGREQ(1, bp, "Queue full, request canceled.");
		g_io_deliver(bp, ENOMEM);
		return;
	}

	bp->bio_driver1 = (void *)sc->sc_seq;
	sc->sc_seq++;
	sc->sc_queue_count++;

	bioq_insert_tail(&sc->sc_inqueue, bp);
	wakeup(sc);

	mtx_unlock(&sc->sc_queue_mtx);
}

static struct g_gate_softc *
g_gate_hold(int unit, const char *name)
{
	struct g_gate_softc *sc = NULL;

	mtx_lock(&g_gate_units_lock);
	if (unit >= 0 && unit < g_gate_maxunits)
		sc = g_gate_units[unit];
	else if (unit == G_GATE_NAME_GIVEN) {
		KASSERT(name != NULL, ("name is NULL"));
		for (unit = 0; unit < g_gate_maxunits; unit++) {
			if (g_gate_units[unit] == NULL)
				continue;
			if (strcmp(name,
			    g_gate_units[unit]->sc_provider->name) != 0) {
				continue;
			}
			sc = g_gate_units[unit];
			break;
		}
	}
	if (sc != NULL)
		sc->sc_ref++;
	mtx_unlock(&g_gate_units_lock);
	return (sc);
}

static void
g_gate_release(struct g_gate_softc *sc)
{

	g_topology_assert_not();
	mtx_lock(&g_gate_units_lock);
	sc->sc_ref--;
	KASSERT(sc->sc_ref >= 0, ("Negative sc_ref for %s.", sc->sc_name));
	if (sc->sc_ref == 0 && (sc->sc_flags & G_GATE_FLAG_DESTROY) != 0)
		wakeup(&sc->sc_ref);
	mtx_unlock(&g_gate_units_lock);
}

static int
g_gate_getunit(int unit, int *errorp)
{

	mtx_assert(&g_gate_units_lock, MA_OWNED);
	if (unit >= 0) {
		if (unit >= g_gate_maxunits)
			*errorp = EINVAL;
		else if (g_gate_units[unit] == NULL)
			return (unit);
		else
			*errorp = EEXIST;
	} else {
		for (unit = 0; unit < g_gate_maxunits; unit++) {
			if (g_gate_units[unit] == NULL)
				return (unit);
		}
		*errorp = ENFILE;
	}
	return (-1);
}

static void
g_gate_guard(void *arg)
{
	struct g_gate_softc *sc;
	struct bintime curtime;
	struct bio *bp, *bp2;

	sc = arg;
	binuptime(&curtime);
	g_gate_hold(sc->sc_unit, NULL);
	mtx_lock(&sc->sc_queue_mtx);
	TAILQ_FOREACH_SAFE(bp, &sc->sc_inqueue.queue, bio_queue, bp2) {
		if (curtime.sec - bp->bio_t0.sec < 5)
			continue;
		bioq_remove(&sc->sc_inqueue, bp);
		sc->sc_queue_count--;
		G_GATE_LOGREQ(1, bp, "Request timeout.");
		g_io_deliver(bp, EIO);
	}
	TAILQ_FOREACH_SAFE(bp, &sc->sc_outqueue.queue, bio_queue, bp2) {
		if (curtime.sec - bp->bio_t0.sec < 5)
			continue;
		bioq_remove(&sc->sc_outqueue, bp);
		sc->sc_queue_count--;
		G_GATE_LOGREQ(1, bp, "Request timeout.");
		g_io_deliver(bp, EIO);
	}
	mtx_unlock(&sc->sc_queue_mtx);
	if ((sc->sc_flags & G_GATE_FLAG_DESTROY) == 0) {
		callout_reset(&sc->sc_callout, sc->sc_timeout * hz,
		    g_gate_guard, sc);
	}
	g_gate_release(sc);
}

static void
g_gate_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
    struct g_consumer *cp, struct g_provider *pp)
{
	struct g_gate_softc *sc;

	sc = gp->softc;
	if (sc == NULL || pp != NULL || cp != NULL)
		return;
	g_gate_hold(sc->sc_unit, NULL);
	if ((sc->sc_flags & G_GATE_FLAG_READONLY) != 0) {
		sbuf_printf(sb, "%s<access>%s</access>\n", indent, "read-only");
	} else if ((sc->sc_flags & G_GATE_FLAG_WRITEONLY) != 0) {
		sbuf_printf(sb, "%s<access>%s</access>\n", indent,
		    "write-only");
	} else {
		sbuf_printf(sb, "%s<access>%s</access>\n", indent,
		    "read-write");
	}
	sbuf_printf(sb, "%s<timeout>%u</timeout>\n", indent, sc->sc_timeout);
	sbuf_printf(sb, "%s<info>%s</info>\n", indent, sc->sc_info);
	sbuf_printf(sb, "%s<queue_count>%u</queue_count>\n", indent,
	    sc->sc_queue_count);
	sbuf_printf(sb, "%s<queue_size>%u</queue_size>\n", indent,
	    sc->sc_queue_size);
	sbuf_printf(sb, "%s<ref>%u</ref>\n", indent, sc->sc_ref);
	sbuf_printf(sb, "%s<unit>%d</unit>\n", indent, sc->sc_unit);
	g_topology_unlock();
	g_gate_release(sc);
	g_topology_lock();
}

static int
g_gate_create(struct g_gate_ctl_create *ggio)
{
	struct g_gate_softc *sc;
	struct g_geom *gp;
	struct g_provider *pp;
	char name[NAME_MAX];
	int error = 0, unit;

	if (ggio->gctl_mediasize == 0) {
		G_GATE_DEBUG(1, "Invalid media size.");
		return (EINVAL);
	}
	if (ggio->gctl_sectorsize > 0 && !powerof2(ggio->gctl_sectorsize)) {
		G_GATE_DEBUG(1, "Invalid sector size.");
		return (EINVAL);
	}
	if ((ggio->gctl_mediasize % ggio->gctl_sectorsize) != 0) {
		G_GATE_DEBUG(1, "Invalid media size.");
		return (EINVAL);
	}
	if ((ggio->gctl_flags & G_GATE_FLAG_READONLY) != 0 &&
	    (ggio->gctl_flags & G_GATE_FLAG_WRITEONLY) != 0) {
		G_GATE_DEBUG(1, "Invalid flags.");
		return (EINVAL);
	}
	if (ggio->gctl_unit != G_GATE_UNIT_AUTO &&
	    ggio->gctl_unit != G_GATE_NAME_GIVEN &&
	    ggio->gctl_unit < 0) {
		G_GATE_DEBUG(1, "Invalid unit number.");
		return (EINVAL);
	}
	if (ggio->gctl_unit == G_GATE_NAME_GIVEN &&
	    ggio->gctl_name[0] == '\0') {
		G_GATE_DEBUG(1, "No device name.");
		return (EINVAL);
	}

	sc = malloc(sizeof(*sc), M_GATE, M_WAITOK | M_ZERO);
	sc->sc_flags = (ggio->gctl_flags & G_GATE_USERFLAGS);
	strlcpy(sc->sc_info, ggio->gctl_info, sizeof(sc->sc_info));
	sc->sc_seq = 1;
	bioq_init(&sc->sc_inqueue);
	bioq_init(&sc->sc_outqueue);
	mtx_init(&sc->sc_queue_mtx, "gg:queue", NULL, MTX_DEF);
	sc->sc_queue_count = 0;
	sc->sc_queue_size = ggio->gctl_maxcount;
	if (sc->sc_queue_size > G_GATE_MAX_QUEUE_SIZE)
		sc->sc_queue_size = G_GATE_MAX_QUEUE_SIZE;
	sc->sc_timeout = ggio->gctl_timeout;
	callout_init(&sc->sc_callout, CALLOUT_MPSAFE);
	mtx_lock(&g_gate_units_lock);
	sc->sc_unit = g_gate_getunit(ggio->gctl_unit, &error);
	if (sc->sc_unit < 0) {
		mtx_unlock(&g_gate_units_lock);
		mtx_destroy(&sc->sc_queue_mtx);
		free(sc, M_GATE);
		return (error);
	}
	if (ggio->gctl_unit == G_GATE_NAME_GIVEN)
		snprintf(name, sizeof(name), "%s", ggio->gctl_name);
	else {
		snprintf(name, sizeof(name), "%s%d", G_GATE_PROVIDER_NAME,
		    sc->sc_unit);
	}
	/* Check for name collision. */
	for (unit = 0; unit < g_gate_maxunits; unit++) {
		if (g_gate_units[unit] == NULL)
			continue;
		if (strcmp(name, g_gate_units[unit]->sc_name) != 0)
			continue;
		mtx_unlock(&g_gate_units_lock);
		mtx_destroy(&sc->sc_queue_mtx);
		free(sc, M_GATE);
		return (EEXIST);
	}
	sc->sc_name = name;
	g_gate_units[sc->sc_unit] = sc;
	g_gate_nunits++;
	mtx_unlock(&g_gate_units_lock);

	ggio->gctl_unit = sc->sc_unit;

	g_topology_lock();
	gp = g_new_geomf(&g_gate_class, "%s", name);
	gp->start = g_gate_start;
	gp->access = g_gate_access;
	gp->dumpconf = g_gate_dumpconf;
	gp->softc = sc;
	pp = g_new_providerf(gp, "%s", name);
	pp->mediasize = ggio->gctl_mediasize;
	pp->sectorsize = ggio->gctl_sectorsize;
	sc->sc_provider = pp;
	g_error_provider(pp, 0);
	g_topology_unlock();
	mtx_lock(&g_gate_units_lock);
	sc->sc_name = sc->sc_provider->name;
	mtx_unlock(&g_gate_units_lock);
	G_GATE_DEBUG(1, "Device %s created.", gp->name);

	if (sc->sc_timeout > 0) {
		callout_reset(&sc->sc_callout, sc->sc_timeout * hz,
		    g_gate_guard, sc);
	}
	return (0);
}

#define	G_GATE_CHECK_VERSION(ggio)	do {				\
	if ((ggio)->gctl_version != G_GATE_VERSION) {			\
		printf("Version mismatch %d != %d.\n",			\
		    ggio->gctl_version, G_GATE_VERSION);		\
		return (EINVAL);					\
	}								\
} while (0)
static int
g_gate_ioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags, struct thread *td)
{
	struct g_gate_softc *sc;
	struct bio *bp;
	int error = 0;

	G_GATE_DEBUG(4, "ioctl(%s, %lx, %p, %x, %p)", devtoname(dev), cmd, addr,
	    flags, td);

	switch (cmd) {
	case G_GATE_CMD_CREATE:
	    {
		struct g_gate_ctl_create *ggio = (void *)addr;

		G_GATE_CHECK_VERSION(ggio);
		error = g_gate_create(ggio);
		/*
		 * Reset TDP_GEOM flag.
		 * There are pending events for sure, because we just created
		 * new provider and other classes want to taste it, but we
		 * cannot answer on I/O requests until we're here.
		 */
		td->td_pflags &= ~TDP_GEOM;
		return (error);
	    }
	case G_GATE_CMD_DESTROY:
	    {
		struct g_gate_ctl_destroy *ggio = (void *)addr;

		G_GATE_CHECK_VERSION(ggio);
		sc = g_gate_hold(ggio->gctl_unit, ggio->gctl_name);
		if (sc == NULL)
			return (ENXIO);
		g_topology_lock();
		mtx_lock(&g_gate_units_lock);
		error = g_gate_destroy(sc, ggio->gctl_force);
		g_topology_unlock();
		if (error != 0)
			g_gate_release(sc);
		return (error);
	    }
	case G_GATE_CMD_CANCEL:
	    {
		struct g_gate_ctl_cancel *ggio = (void *)addr;
		struct bio *tbp, *lbp;

		G_GATE_CHECK_VERSION(ggio);
		sc = g_gate_hold(ggio->gctl_unit, ggio->gctl_name);
		if (sc == NULL)
			return (ENXIO);
		lbp = NULL;
		mtx_lock(&sc->sc_queue_mtx);
		TAILQ_FOREACH_SAFE(bp, &sc->sc_outqueue.queue, bio_queue, tbp) {
			if (ggio->gctl_seq == 0 ||
			    ggio->gctl_seq == (uintptr_t)bp->bio_driver1) {
				G_GATE_LOGREQ(1, bp, "Request canceled.");
				bioq_remove(&sc->sc_outqueue, bp);
				/*
				 * Be sure to put requests back onto incoming
				 * queue in the proper order.
				 */
				if (lbp == NULL)
					bioq_insert_head(&sc->sc_inqueue, bp);
				else {
					TAILQ_INSERT_AFTER(&sc->sc_inqueue.queue,
					    lbp, bp, bio_queue);
				}
				lbp = bp;
				/*
				 * If only one request was canceled, leave now.
				 */
				if (ggio->gctl_seq != 0)
					break;
			}
		}
		if (ggio->gctl_unit == G_GATE_NAME_GIVEN)
			ggio->gctl_unit = sc->sc_unit;
		mtx_unlock(&sc->sc_queue_mtx);
		g_gate_release(sc);
		return (error);
	    }
	case G_GATE_CMD_START:
	    {
		struct g_gate_ctl_io *ggio = (void *)addr;

		G_GATE_CHECK_VERSION(ggio);
		sc = g_gate_hold(ggio->gctl_unit, NULL);
		if (sc == NULL)
			return (ENXIO);
		error = 0;
		for (;;) {
			mtx_lock(&sc->sc_queue_mtx);
			bp = bioq_first(&sc->sc_inqueue);
			if (bp != NULL)
				break;
			if ((sc->sc_flags & G_GATE_FLAG_DESTROY) != 0) {
				ggio->gctl_error = ECANCELED;
				mtx_unlock(&sc->sc_queue_mtx);
				goto start_end;
			}
			if (msleep(sc, &sc->sc_queue_mtx,
			    PPAUSE | PDROP | PCATCH, "ggwait", 0) != 0) {
				ggio->gctl_error = ECANCELED;
				goto start_end;
			}
		}
		ggio->gctl_cmd = bp->bio_cmd;
		if ((bp->bio_cmd == BIO_DELETE || bp->bio_cmd == BIO_WRITE) &&
		    bp->bio_length > ggio->gctl_length) {
			mtx_unlock(&sc->sc_queue_mtx);
			ggio->gctl_length = bp->bio_length;
			ggio->gctl_error = ENOMEM;
			goto start_end;
		}
		bioq_remove(&sc->sc_inqueue, bp);
		bioq_insert_tail(&sc->sc_outqueue, bp);
		mtx_unlock(&sc->sc_queue_mtx);

		ggio->gctl_seq = (uintptr_t)bp->bio_driver1;
		ggio->gctl_offset = bp->bio_offset;
		ggio->gctl_length = bp->bio_length;

		switch (bp->bio_cmd) {
		case BIO_READ:
		case BIO_DELETE:
		case BIO_FLUSH:
			break;
		case BIO_WRITE:
			error = copyout(bp->bio_data, ggio->gctl_data,
			    bp->bio_length);
			if (error != 0) {
				mtx_lock(&sc->sc_queue_mtx);
				bioq_remove(&sc->sc_outqueue, bp);
				bioq_insert_head(&sc->sc_inqueue, bp);
				mtx_unlock(&sc->sc_queue_mtx);
				goto start_end;
			}
			break;
		}
start_end:
		g_gate_release(sc);
		return (error);
	    }
	case G_GATE_CMD_DONE:
	    {
		struct g_gate_ctl_io *ggio = (void *)addr;

		G_GATE_CHECK_VERSION(ggio);
		sc = g_gate_hold(ggio->gctl_unit, NULL);
		if (sc == NULL)
			return (ENOENT);
		error = 0;
		mtx_lock(&sc->sc_queue_mtx);
		TAILQ_FOREACH(bp, &sc->sc_outqueue.queue, bio_queue) {
			if (ggio->gctl_seq == (uintptr_t)bp->bio_driver1)
				break;
		}
		if (bp != NULL) {
			bioq_remove(&sc->sc_outqueue, bp);
			sc->sc_queue_count--;
		}
		mtx_unlock(&sc->sc_queue_mtx);
		if (bp == NULL) {
			/*
			 * Request was probably canceled.
			 */
			goto done_end;
		}
		if (ggio->gctl_error == EAGAIN) {
			bp->bio_error = 0;
			G_GATE_LOGREQ(1, bp, "Request desisted.");
			mtx_lock(&sc->sc_queue_mtx);
			sc->sc_queue_count++;
			bioq_insert_head(&sc->sc_inqueue, bp);
			wakeup(sc);
			mtx_unlock(&sc->sc_queue_mtx);
		} else {
			bp->bio_error = ggio->gctl_error;
			if (bp->bio_error == 0) {
				bp->bio_completed = bp->bio_length;
				switch (bp->bio_cmd) {
				case BIO_READ:
					error = copyin(ggio->gctl_data,
					    bp->bio_data, bp->bio_length);
					if (error != 0)
						bp->bio_error = error;
					break;
				case BIO_DELETE:
				case BIO_WRITE:
				case BIO_FLUSH:
					break;
				}
			}
			G_GATE_LOGREQ(2, bp, "Request done.");
			g_io_deliver(bp, bp->bio_error);
		}
done_end:
		g_gate_release(sc);
		return (error);
	    }
	}
	return (ENOIOCTL);
}

static void
g_gate_device(void)
{

	status_dev = make_dev(&g_gate_cdevsw, 0x0, UID_ROOT, GID_WHEEL, 0600,
	    G_GATE_CTL_NAME);
}

static int
g_gate_modevent(module_t mod, int type, void *data)
{
	int error = 0;

	switch (type) {
	case MOD_LOAD:
		mtx_init(&g_gate_units_lock, "gg_units_lock", NULL, MTX_DEF);
		g_gate_units = malloc(g_gate_maxunits * sizeof(g_gate_units[0]),
		    M_GATE, M_WAITOK | M_ZERO);
		g_gate_nunits = 0;
		g_gate_device();
		break;
	case MOD_UNLOAD:
		mtx_lock(&g_gate_units_lock);
		if (g_gate_nunits > 0) {
			mtx_unlock(&g_gate_units_lock);
			error = EBUSY;
			break;
		}
		mtx_unlock(&g_gate_units_lock);
		mtx_destroy(&g_gate_units_lock);
		if (status_dev != 0)
			destroy_dev(status_dev);
		free(g_gate_units, M_GATE);
		break;
	default:
		return (EOPNOTSUPP);
		break;
	}

	return (error);
}
static moduledata_t g_gate_module = {
	G_GATE_MOD_NAME,
	g_gate_modevent,
	NULL
};
DECLARE_MODULE(geom_gate, g_gate_module, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
DECLARE_GEOM_CLASS(g_gate_class, g_gate);
OpenPOWER on IntegriCloud