Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
  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
/*
 *  CCW device PGID and path verification I/O handling.
 *
 *    Copyright IBM Corp. 2002, 2009
 *    Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
 *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
 *		 Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
 */

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/bitops.h>
#include <asm/ccwdev.h>
#include <asm/cio.h>

#include "cio.h"
#include "cio_debug.h"
#include "device.h"
#include "io_sch.h"

#define PGID_RETRIES	256
#define PGID_TIMEOUT	(10 * HZ)

static void verify_start(struct ccw_device *cdev);

/*
 * Process path verification data and report result.
 */
static void verify_done(struct ccw_device *cdev, int rc)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw_dev_id *id = &cdev->private->dev_id;
	int mpath = cdev->private->flags.mpath;
	int pgroup = cdev->private->flags.pgroup;

	if (rc)
		goto out;
	/* Ensure consistent multipathing state at device and channel. */
	if (sch->config.mp != mpath) {
		sch->config.mp = mpath;
		rc = cio_commit_config(sch);
	}
out:
	CIO_MSG_EVENT(2, "vrfy: device 0.%x.%04x: rc=%d pgroup=%d mpath=%d "
			 "vpm=%02x\n", id->ssid, id->devno, rc, pgroup, mpath,
			 sch->vpm);
	ccw_device_verify_done(cdev, rc);
}

/*
 * Create channel program to perform a NOOP.
 */
static void nop_build_cp(struct ccw_device *cdev)
{
	struct ccw_request *req = &cdev->private->req;
	struct ccw1 *cp = cdev->private->iccws;

	cp->cmd_code	= CCW_CMD_NOOP;
	cp->cda		= 0;
	cp->count	= 0;
	cp->flags	= CCW_FLAG_SLI;
	req->cp		= cp;
}

/*
 * Perform NOOP on a single path.
 */
static void nop_do(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw_request *req = &cdev->private->req;

	req->lpm = lpm_adjust(req->lpm, sch->schib.pmcw.pam & sch->opm &
			      ~cdev->private->path_noirq_mask);
	if (!req->lpm)
		goto out_nopath;
	nop_build_cp(cdev);
	ccw_request_start(cdev);
	return;

out_nopath:
	verify_done(cdev, sch->vpm ? 0 : -EACCES);
}

/*
 * Adjust NOOP I/O status.
 */
static enum io_status nop_filter(struct ccw_device *cdev, void *data,
				 struct irb *irb, enum io_status status)
{
	/* Only subchannel status might indicate a path error. */
	if (status == IO_STATUS_ERROR && irb->scsw.cmd.cstat == 0)
		return IO_DONE;
	return status;
}

/*
 * Process NOOP request result for a single path.
 */
static void nop_callback(struct ccw_device *cdev, void *data, int rc)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw_request *req = &cdev->private->req;

	switch (rc) {
	case 0:
		sch->vpm |= req->lpm;
		break;
	case -ETIME:
		cdev->private->path_noirq_mask |= req->lpm;
		break;
	case -EACCES:
		cdev->private->path_notoper_mask |= req->lpm;
		break;
	default:
		goto err;
	}
	/* Continue on the next path. */
	req->lpm >>= 1;
	nop_do(cdev);
	return;

err:
	verify_done(cdev, rc);
}

/*
 * Create channel program to perform SET PGID on a single path.
 */
static void spid_build_cp(struct ccw_device *cdev, u8 fn)
{
	struct ccw_request *req = &cdev->private->req;
	struct ccw1 *cp = cdev->private->iccws;
	int i = 8 - ffs(req->lpm);
	struct pgid *pgid = &cdev->private->pgid[i];

	pgid->inf.fc	= fn;
	cp->cmd_code	= CCW_CMD_SET_PGID;
	cp->cda		= (u32) (addr_t) pgid;
	cp->count	= sizeof(*pgid);
	cp->flags	= CCW_FLAG_SLI;
	req->cp		= cp;
}

static void pgid_wipeout_callback(struct ccw_device *cdev, void *data, int rc)
{
	if (rc) {
		/* We don't know the path groups' state. Abort. */
		verify_done(cdev, rc);
		return;
	}
	/*
	 * Path groups have been reset. Restart path verification but
	 * leave paths in path_noirq_mask out.
	 */
	cdev->private->flags.pgid_unknown = 0;
	verify_start(cdev);
}

/*
 * Reset pathgroups and restart path verification, leave unusable paths out.
 */
static void pgid_wipeout_start(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw_dev_id *id = &cdev->private->dev_id;
	struct ccw_request *req = &cdev->private->req;
	u8 fn;

	CIO_MSG_EVENT(2, "wipe: device 0.%x.%04x: pvm=%02x nim=%02x\n",
		      id->ssid, id->devno, cdev->private->pgid_valid_mask,
		      cdev->private->path_noirq_mask);

	/* Initialize request data. */
	memset(req, 0, sizeof(*req));
	req->timeout	= PGID_TIMEOUT;
	req->maxretries	= PGID_RETRIES;
	req->lpm	= sch->schib.pmcw.pam;
	req->callback	= pgid_wipeout_callback;
	fn = SPID_FUNC_DISBAND;
	if (cdev->private->flags.mpath)
		fn |= SPID_FUNC_MULTI_PATH;
	spid_build_cp(cdev, fn);
	ccw_request_start(cdev);
}

/*
 * Perform establish/resign SET PGID on a single path.
 */
static void spid_do(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw_request *req = &cdev->private->req;
	u8 fn;

	/* Use next available path that is not already in correct state. */
	req->lpm = lpm_adjust(req->lpm, cdev->private->pgid_todo_mask);
	if (!req->lpm)
		goto out_nopath;
	/* Channel program setup. */
	if (req->lpm & sch->opm)
		fn = SPID_FUNC_ESTABLISH;
	else
		fn = SPID_FUNC_RESIGN;
	if (cdev->private->flags.mpath)
		fn |= SPID_FUNC_MULTI_PATH;
	spid_build_cp(cdev, fn);
	ccw_request_start(cdev);
	return;

out_nopath:
	if (cdev->private->flags.pgid_unknown) {
		/* At least one SPID could be partially done. */
		pgid_wipeout_start(cdev);
		return;
	}
	verify_done(cdev, sch->vpm ? 0 : -EACCES);
}

/*
 * Process SET PGID request result for a single path.
 */
static void spid_callback(struct ccw_device *cdev, void *data, int rc)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw_request *req = &cdev->private->req;

	switch (rc) {
	case 0:
		sch->vpm |= req->lpm & sch->opm;
		break;
	case -ETIME:
		cdev->private->flags.pgid_unknown = 1;
		cdev->private->path_noirq_mask |= req->lpm;
		break;
	case -EACCES:
		cdev->private->path_notoper_mask |= req->lpm;
		break;
	case -EOPNOTSUPP:
		if (cdev->private->flags.mpath) {
			/* Try without multipathing. */
			cdev->private->flags.mpath = 0;
			goto out_restart;
		}
		/* Try without pathgrouping. */
		cdev->private->flags.pgroup = 0;
		goto out_restart;
	default:
		goto err;
	}
	req->lpm >>= 1;
	spid_do(cdev);
	return;

out_restart:
	verify_start(cdev);
	return;
err:
	verify_done(cdev, rc);
}

static void spid_start(struct ccw_device *cdev)
{
	struct ccw_request *req = &cdev->private->req;

	/* Initialize request data. */
	memset(req, 0, sizeof(*req));
	req->timeout	= PGID_TIMEOUT;
	req->maxretries	= PGID_RETRIES;
	req->lpm	= 0x80;
	req->singlepath	= 1;
	req->callback	= spid_callback;
	spid_do(cdev);
}

static int pgid_is_reset(struct pgid *p)
{
	char *c;

	for (c = (char *)p + 1; c < (char *)(p + 1); c++) {
		if (*c != 0)
			return 0;
	}
	return 1;
}

static int pgid_cmp(struct pgid *p1, struct pgid *p2)
{
	return memcmp((char *) p1 + 1, (char *) p2 + 1,
		      sizeof(struct pgid) - 1);
}

/*
 * Determine pathgroup state from PGID data.
 */
static void pgid_analyze(struct ccw_device *cdev, struct pgid **p,
			 int *mismatch, u8 *reserved, u8 *reset)
{
	struct pgid *pgid = &cdev->private->pgid[0];
	struct pgid *first = NULL;
	int lpm;
	int i;

	*mismatch = 0;
	*reserved = 0;
	*reset = 0;
	for (i = 0, lpm = 0x80; i < 8; i++, pgid++, lpm >>= 1) {
		if ((cdev->private->pgid_valid_mask & lpm) == 0)
			continue;
		if (pgid->inf.ps.state2 == SNID_STATE2_RESVD_ELSE)
			*reserved |= lpm;
		if (pgid_is_reset(pgid)) {
			*reset |= lpm;
			continue;
		}
		if (!first) {
			first = pgid;
			continue;
		}
		if (pgid_cmp(pgid, first) != 0)
			*mismatch = 1;
	}
	if (!first)
		first = &channel_subsystems[0]->global_pgid;
	*p = first;
}

static u8 pgid_to_donepm(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct pgid *pgid;
	int i;
	int lpm;
	u8 donepm = 0;

	/* Set bits for paths which are already in the target state. */
	for (i = 0; i < 8; i++) {
		lpm = 0x80 >> i;
		if ((cdev->private->pgid_valid_mask & lpm) == 0)
			continue;
		pgid = &cdev->private->pgid[i];
		if (sch->opm & lpm) {
			if (pgid->inf.ps.state1 != SNID_STATE1_GROUPED)
				continue;
		} else {
			if (pgid->inf.ps.state1 != SNID_STATE1_UNGROUPED)
				continue;
		}
		if (cdev->private->flags.mpath) {
			if (pgid->inf.ps.state3 != SNID_STATE3_MULTI_PATH)
				continue;
		} else {
			if (pgid->inf.ps.state3 != SNID_STATE3_SINGLE_PATH)
				continue;
		}
		donepm |= lpm;
	}

	return donepm;
}

static void pgid_fill(struct ccw_device *cdev, struct pgid *pgid)
{
	int i;

	for (i = 0; i < 8; i++)
		memcpy(&cdev->private->pgid[i], pgid, sizeof(struct pgid));
}

/*
 * Process SENSE PGID data and report result.
 */
static void snid_done(struct ccw_device *cdev, int rc)
{
	struct ccw_dev_id *id = &cdev->private->dev_id;
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct pgid *pgid;
	int mismatch = 0;
	u8 reserved = 0;
	u8 reset = 0;
	u8 donepm;

	if (rc)
		goto out;
	pgid_analyze(cdev, &pgid, &mismatch, &reserved, &reset);
	if (reserved == cdev->private->pgid_valid_mask)
		rc = -EUSERS;
	else if (mismatch)
		rc = -EOPNOTSUPP;
	else {
		donepm = pgid_to_donepm(cdev);
		sch->vpm = donepm & sch->opm;
		cdev->private->pgid_reset_mask |= reset;
		cdev->private->pgid_todo_mask &=
			~(donepm | cdev->private->path_noirq_mask);
		pgid_fill(cdev, pgid);
	}
out:
	CIO_MSG_EVENT(2, "snid: device 0.%x.%04x: rc=%d pvm=%02x vpm=%02x "
		      "todo=%02x mism=%d rsvd=%02x reset=%02x\n", id->ssid,
		      id->devno, rc, cdev->private->pgid_valid_mask, sch->vpm,
		      cdev->private->pgid_todo_mask, mismatch, reserved, reset);
	switch (rc) {
	case 0:
		if (cdev->private->flags.pgid_unknown) {
			pgid_wipeout_start(cdev);
			return;
		}
		/* Anything left to do? */
		if (cdev->private->pgid_todo_mask == 0) {
			verify_done(cdev, sch->vpm == 0 ? -EACCES : 0);
			return;
		}
		/* Perform path-grouping. */
		spid_start(cdev);
		break;
	case -EOPNOTSUPP:
		/* Path-grouping not supported. */
		cdev->private->flags.pgroup = 0;
		cdev->private->flags.mpath = 0;
		verify_start(cdev);
		break;
	default:
		verify_done(cdev, rc);
	}
}

/*
 * Create channel program to perform a SENSE PGID on a single path.
 */
static void snid_build_cp(struct ccw_device *cdev)
{
	struct ccw_request *req = &cdev->private->req;
	struct ccw1 *cp = cdev->private->iccws;
	int i = 8 - ffs(req->lpm);

	/* Channel program setup. */
	cp->cmd_code	= CCW_CMD_SENSE_PGID;
	cp->cda		= (u32) (addr_t) &cdev->private->pgid[i];
	cp->count	= sizeof(struct pgid);
	cp->flags	= CCW_FLAG_SLI;
	req->cp		= cp;
}

/*
 * Perform SENSE PGID on a single path.
 */
static void snid_do(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw_request *req = &cdev->private->req;
	int ret;

	req->lpm = lpm_adjust(req->lpm, sch->schib.pmcw.pam &
			      ~cdev->private->path_noirq_mask);
	if (!req->lpm)
		goto out_nopath;
	snid_build_cp(cdev);
	ccw_request_start(cdev);
	return;

out_nopath:
	if (cdev->private->pgid_valid_mask)
		ret = 0;
	else if (cdev->private->path_noirq_mask)
		ret = -ETIME;
	else
		ret = -EACCES;
	snid_done(cdev, ret);
}

/*
 * Process SENSE PGID request result for single path.
 */
static void snid_callback(struct ccw_device *cdev, void *data, int rc)
{
	struct ccw_request *req = &cdev->private->req;

	switch (rc) {
	case 0:
		cdev->private->pgid_valid_mask |= req->lpm;
		break;
	case -ETIME:
		cdev->private->flags.pgid_unknown = 1;
		cdev->private->path_noirq_mask |= req->lpm;
		break;
	case -EACCES:
		cdev->private->path_notoper_mask |= req->lpm;
		break;
	default:
		goto err;
	}
	/* Continue on the next path. */
	req->lpm >>= 1;
	snid_do(cdev);
	return;

err:
	snid_done(cdev, rc);
}

/*
 * Perform path verification.
 */
static void verify_start(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw_request *req = &cdev->private->req;
	struct ccw_dev_id *devid = &cdev->private->dev_id;

	sch->vpm = 0;
	sch->lpm = sch->schib.pmcw.pam;

	/* Initialize PGID data. */
	memset(cdev->private->pgid, 0, sizeof(cdev->private->pgid));
	cdev->private->pgid_valid_mask = 0;
	cdev->private->pgid_todo_mask = sch->schib.pmcw.pam;
	cdev->private->path_notoper_mask = 0;

	/* Initialize request data. */
	memset(req, 0, sizeof(*req));
	req->timeout	= PGID_TIMEOUT;
	req->maxretries	= PGID_RETRIES;
	req->lpm	= 0x80;
	req->singlepath	= 1;
	if (cdev->private->flags.pgroup) {
		CIO_TRACE_EVENT(4, "snid");
		CIO_HEX_EVENT(4, devid, sizeof(*devid));
		req->callback	= snid_callback;
		snid_do(cdev);
	} else {
		CIO_TRACE_EVENT(4, "nop");
		CIO_HEX_EVENT(4, devid, sizeof(*devid));
		req->filter	= nop_filter;
		req->callback	= nop_callback;
		nop_do(cdev);
	}
}

/**
 * ccw_device_verify_start - perform path verification
 * @cdev: ccw device
 *
 * Perform an I/O on each available channel path to @cdev to determine which
 * paths are operational. The resulting path mask is stored in sch->vpm.
 * If device options specify pathgrouping, establish a pathgroup for the
 * operational paths. When finished, call ccw_device_verify_done with a
 * return code specifying the result.
 */
void ccw_device_verify_start(struct ccw_device *cdev)
{
	CIO_TRACE_EVENT(4, "vrfy");
	CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
	/*
	 * Initialize pathgroup and multipath state with target values.
	 * They may change in the course of path verification.
	 */
	cdev->private->flags.pgroup = cdev->private->options.pgroup;
	cdev->private->flags.mpath = cdev->private->options.mpath;
	cdev->private->flags.doverify = 0;
	cdev->private->path_noirq_mask = 0;
	verify_start(cdev);
}

/*
 * Process disband SET PGID request result.
 */
static void disband_callback(struct ccw_device *cdev, void *data, int rc)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw_dev_id *id = &cdev->private->dev_id;

	if (rc)
		goto out;
	/* Ensure consistent multipathing state at device and channel. */
	cdev->private->flags.mpath = 0;
	if (sch->config.mp) {
		sch->config.mp = 0;
		rc = cio_commit_config(sch);
	}
out:
	CIO_MSG_EVENT(0, "disb: device 0.%x.%04x: rc=%d\n", id->ssid, id->devno,
		      rc);
	ccw_device_disband_done(cdev, rc);
}

/**
 * ccw_device_disband_start - disband pathgroup
 * @cdev: ccw device
 *
 * Execute a SET PGID channel program on @cdev to disband a previously
 * established pathgroup. When finished, call ccw_device_disband_done with
 * a return code specifying the result.
 */
void ccw_device_disband_start(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw_request *req = &cdev->private->req;
	u8 fn;

	CIO_TRACE_EVENT(4, "disb");
	CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
	/* Request setup. */
	memset(req, 0, sizeof(*req));
	req->timeout	= PGID_TIMEOUT;
	req->maxretries	= PGID_RETRIES;
	req->lpm	= sch->schib.pmcw.pam & sch->opm;
	req->singlepath	= 1;
	req->callback	= disband_callback;
	fn = SPID_FUNC_DISBAND;
	if (cdev->private->flags.mpath)
		fn |= SPID_FUNC_MULTI_PATH;
	spid_build_cp(cdev, fn);
	ccw_request_start(cdev);
}

static void stlck_build_cp(struct ccw_device *cdev, void *buf1, void *buf2)
{
	struct ccw_request *req = &cdev->private->req;
	struct ccw1 *cp = cdev->private->iccws;

	cp[0].cmd_code = CCW_CMD_STLCK;
	cp[0].cda = (u32) (addr_t) buf1;
	cp[0].count = 32;
	cp[0].flags = CCW_FLAG_CC;
	cp[1].cmd_code = CCW_CMD_RELEASE;
	cp[1].cda = (u32) (addr_t) buf2;
	cp[1].count = 32;
	cp[1].flags = 0;
	req->cp = cp;
}

static void stlck_callback(struct ccw_device *cdev, void *data, int rc)
{
	ccw_device_stlck_done(cdev, data, rc);
}

/**
 * ccw_device_stlck_start - perform unconditional release
 * @cdev: ccw device
 * @data: data pointer to be passed to ccw_device_stlck_done
 * @buf1: data pointer used in channel program
 * @buf2: data pointer used in channel program
 *
 * Execute a channel program on @cdev to release an existing PGID reservation.
 * When finished, call ccw_device_stlck_done with a return code specifying the
 * result.
 */
void ccw_device_stlck_start(struct ccw_device *cdev, void *data, void *buf1,
			    void *buf2)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw_request *req = &cdev->private->req;

	CIO_TRACE_EVENT(4, "stlck");
	CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
	/* Request setup. */
	memset(req, 0, sizeof(*req));
	req->timeout	= PGID_TIMEOUT;
	req->maxretries	= PGID_RETRIES;
	req->lpm	= sch->schib.pmcw.pam & sch->opm;
	req->data	= data;
	req->callback	= stlck_callback;
	stlck_build_cp(cdev, buf1, buf2);
	ccw_request_start(cdev);
}