xref: /openbmc/linux/drivers/s390/cio/device_pgid.c (revision dea54fba)
1 /*
2  *  CCW device PGID and path verification I/O handling.
3  *
4  *    Copyright IBM Corp. 2002, 2009
5  *    Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
6  *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
7  *		 Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
8  */
9 
10 #include <linux/kernel.h>
11 #include <linux/string.h>
12 #include <linux/bitops.h>
13 #include <linux/types.h>
14 #include <linux/errno.h>
15 #include <linux/slab.h>
16 #include <asm/ccwdev.h>
17 #include <asm/cio.h>
18 
19 #include "cio.h"
20 #include "cio_debug.h"
21 #include "device.h"
22 #include "io_sch.h"
23 
24 #define PGID_RETRIES	256
25 #define PGID_TIMEOUT	(10 * HZ)
26 
27 static void verify_start(struct ccw_device *cdev);
28 
29 /*
30  * Process path verification data and report result.
31  */
32 static void verify_done(struct ccw_device *cdev, int rc)
33 {
34 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
35 	struct ccw_dev_id *id = &cdev->private->dev_id;
36 	int mpath = cdev->private->flags.mpath;
37 	int pgroup = cdev->private->flags.pgroup;
38 
39 	if (rc)
40 		goto out;
41 	/* Ensure consistent multipathing state at device and channel. */
42 	if (sch->config.mp != mpath) {
43 		sch->config.mp = mpath;
44 		rc = cio_commit_config(sch);
45 	}
46 out:
47 	CIO_MSG_EVENT(2, "vrfy: device 0.%x.%04x: rc=%d pgroup=%d mpath=%d "
48 			 "vpm=%02x\n", id->ssid, id->devno, rc, pgroup, mpath,
49 			 sch->vpm);
50 	ccw_device_verify_done(cdev, rc);
51 }
52 
53 /*
54  * Create channel program to perform a NOOP.
55  */
56 static void nop_build_cp(struct ccw_device *cdev)
57 {
58 	struct ccw_request *req = &cdev->private->req;
59 	struct ccw1 *cp = cdev->private->iccws;
60 
61 	cp->cmd_code	= CCW_CMD_NOOP;
62 	cp->cda		= 0;
63 	cp->count	= 0;
64 	cp->flags	= CCW_FLAG_SLI;
65 	req->cp		= cp;
66 }
67 
68 /*
69  * Perform NOOP on a single path.
70  */
71 static void nop_do(struct ccw_device *cdev)
72 {
73 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
74 	struct ccw_request *req = &cdev->private->req;
75 
76 	req->lpm = lpm_adjust(req->lpm, sch->schib.pmcw.pam & sch->opm &
77 			      ~cdev->private->path_noirq_mask);
78 	if (!req->lpm)
79 		goto out_nopath;
80 	nop_build_cp(cdev);
81 	ccw_request_start(cdev);
82 	return;
83 
84 out_nopath:
85 	verify_done(cdev, sch->vpm ? 0 : -EACCES);
86 }
87 
88 /*
89  * Adjust NOOP I/O status.
90  */
91 static enum io_status nop_filter(struct ccw_device *cdev, void *data,
92 				 struct irb *irb, enum io_status status)
93 {
94 	/* Only subchannel status might indicate a path error. */
95 	if (status == IO_STATUS_ERROR && irb->scsw.cmd.cstat == 0)
96 		return IO_DONE;
97 	return status;
98 }
99 
100 /*
101  * Process NOOP request result for a single path.
102  */
103 static void nop_callback(struct ccw_device *cdev, void *data, int rc)
104 {
105 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
106 	struct ccw_request *req = &cdev->private->req;
107 
108 	switch (rc) {
109 	case 0:
110 		sch->vpm |= req->lpm;
111 		break;
112 	case -ETIME:
113 		cdev->private->path_noirq_mask |= req->lpm;
114 		break;
115 	case -EACCES:
116 		cdev->private->path_notoper_mask |= req->lpm;
117 		break;
118 	default:
119 		goto err;
120 	}
121 	/* Continue on the next path. */
122 	req->lpm >>= 1;
123 	nop_do(cdev);
124 	return;
125 
126 err:
127 	verify_done(cdev, rc);
128 }
129 
130 /*
131  * Create channel program to perform SET PGID on a single path.
132  */
133 static void spid_build_cp(struct ccw_device *cdev, u8 fn)
134 {
135 	struct ccw_request *req = &cdev->private->req;
136 	struct ccw1 *cp = cdev->private->iccws;
137 	int i = pathmask_to_pos(req->lpm);
138 	struct pgid *pgid = &cdev->private->pgid[i];
139 
140 	pgid->inf.fc	= fn;
141 	cp->cmd_code	= CCW_CMD_SET_PGID;
142 	cp->cda		= (u32) (addr_t) pgid;
143 	cp->count	= sizeof(*pgid);
144 	cp->flags	= CCW_FLAG_SLI;
145 	req->cp		= cp;
146 }
147 
148 static void pgid_wipeout_callback(struct ccw_device *cdev, void *data, int rc)
149 {
150 	if (rc) {
151 		/* We don't know the path groups' state. Abort. */
152 		verify_done(cdev, rc);
153 		return;
154 	}
155 	/*
156 	 * Path groups have been reset. Restart path verification but
157 	 * leave paths in path_noirq_mask out.
158 	 */
159 	cdev->private->flags.pgid_unknown = 0;
160 	verify_start(cdev);
161 }
162 
163 /*
164  * Reset pathgroups and restart path verification, leave unusable paths out.
165  */
166 static void pgid_wipeout_start(struct ccw_device *cdev)
167 {
168 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
169 	struct ccw_dev_id *id = &cdev->private->dev_id;
170 	struct ccw_request *req = &cdev->private->req;
171 	u8 fn;
172 
173 	CIO_MSG_EVENT(2, "wipe: device 0.%x.%04x: pvm=%02x nim=%02x\n",
174 		      id->ssid, id->devno, cdev->private->pgid_valid_mask,
175 		      cdev->private->path_noirq_mask);
176 
177 	/* Initialize request data. */
178 	memset(req, 0, sizeof(*req));
179 	req->timeout	= PGID_TIMEOUT;
180 	req->maxretries	= PGID_RETRIES;
181 	req->lpm	= sch->schib.pmcw.pam;
182 	req->callback	= pgid_wipeout_callback;
183 	fn = SPID_FUNC_DISBAND;
184 	if (cdev->private->flags.mpath)
185 		fn |= SPID_FUNC_MULTI_PATH;
186 	spid_build_cp(cdev, fn);
187 	ccw_request_start(cdev);
188 }
189 
190 /*
191  * Perform establish/resign SET PGID on a single path.
192  */
193 static void spid_do(struct ccw_device *cdev)
194 {
195 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
196 	struct ccw_request *req = &cdev->private->req;
197 	u8 fn;
198 
199 	/* Use next available path that is not already in correct state. */
200 	req->lpm = lpm_adjust(req->lpm, cdev->private->pgid_todo_mask);
201 	if (!req->lpm)
202 		goto out_nopath;
203 	/* Channel program setup. */
204 	if (req->lpm & sch->opm)
205 		fn = SPID_FUNC_ESTABLISH;
206 	else
207 		fn = SPID_FUNC_RESIGN;
208 	if (cdev->private->flags.mpath)
209 		fn |= SPID_FUNC_MULTI_PATH;
210 	spid_build_cp(cdev, fn);
211 	ccw_request_start(cdev);
212 	return;
213 
214 out_nopath:
215 	if (cdev->private->flags.pgid_unknown) {
216 		/* At least one SPID could be partially done. */
217 		pgid_wipeout_start(cdev);
218 		return;
219 	}
220 	verify_done(cdev, sch->vpm ? 0 : -EACCES);
221 }
222 
223 /*
224  * Process SET PGID request result for a single path.
225  */
226 static void spid_callback(struct ccw_device *cdev, void *data, int rc)
227 {
228 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
229 	struct ccw_request *req = &cdev->private->req;
230 
231 	switch (rc) {
232 	case 0:
233 		sch->vpm |= req->lpm & sch->opm;
234 		break;
235 	case -ETIME:
236 		cdev->private->flags.pgid_unknown = 1;
237 		cdev->private->path_noirq_mask |= req->lpm;
238 		break;
239 	case -EACCES:
240 		cdev->private->path_notoper_mask |= req->lpm;
241 		break;
242 	case -EOPNOTSUPP:
243 		if (cdev->private->flags.mpath) {
244 			/* Try without multipathing. */
245 			cdev->private->flags.mpath = 0;
246 			goto out_restart;
247 		}
248 		/* Try without pathgrouping. */
249 		cdev->private->flags.pgroup = 0;
250 		goto out_restart;
251 	default:
252 		goto err;
253 	}
254 	req->lpm >>= 1;
255 	spid_do(cdev);
256 	return;
257 
258 out_restart:
259 	verify_start(cdev);
260 	return;
261 err:
262 	verify_done(cdev, rc);
263 }
264 
265 static void spid_start(struct ccw_device *cdev)
266 {
267 	struct ccw_request *req = &cdev->private->req;
268 
269 	/* Initialize request data. */
270 	memset(req, 0, sizeof(*req));
271 	req->timeout	= PGID_TIMEOUT;
272 	req->maxretries	= PGID_RETRIES;
273 	req->lpm	= 0x80;
274 	req->singlepath	= 1;
275 	req->callback	= spid_callback;
276 	spid_do(cdev);
277 }
278 
279 static int pgid_is_reset(struct pgid *p)
280 {
281 	char *c;
282 
283 	for (c = (char *)p + 1; c < (char *)(p + 1); c++) {
284 		if (*c != 0)
285 			return 0;
286 	}
287 	return 1;
288 }
289 
290 static int pgid_cmp(struct pgid *p1, struct pgid *p2)
291 {
292 	return memcmp((char *) p1 + 1, (char *) p2 + 1,
293 		      sizeof(struct pgid) - 1);
294 }
295 
296 /*
297  * Determine pathgroup state from PGID data.
298  */
299 static void pgid_analyze(struct ccw_device *cdev, struct pgid **p,
300 			 int *mismatch, u8 *reserved, u8 *reset)
301 {
302 	struct pgid *pgid = &cdev->private->pgid[0];
303 	struct pgid *first = NULL;
304 	int lpm;
305 	int i;
306 
307 	*mismatch = 0;
308 	*reserved = 0;
309 	*reset = 0;
310 	for (i = 0, lpm = 0x80; i < 8; i++, pgid++, lpm >>= 1) {
311 		if ((cdev->private->pgid_valid_mask & lpm) == 0)
312 			continue;
313 		if (pgid->inf.ps.state2 == SNID_STATE2_RESVD_ELSE)
314 			*reserved |= lpm;
315 		if (pgid_is_reset(pgid)) {
316 			*reset |= lpm;
317 			continue;
318 		}
319 		if (!first) {
320 			first = pgid;
321 			continue;
322 		}
323 		if (pgid_cmp(pgid, first) != 0)
324 			*mismatch = 1;
325 	}
326 	if (!first)
327 		first = &channel_subsystems[0]->global_pgid;
328 	*p = first;
329 }
330 
331 static u8 pgid_to_donepm(struct ccw_device *cdev)
332 {
333 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
334 	struct pgid *pgid;
335 	int i;
336 	int lpm;
337 	u8 donepm = 0;
338 
339 	/* Set bits for paths which are already in the target state. */
340 	for (i = 0; i < 8; i++) {
341 		lpm = 0x80 >> i;
342 		if ((cdev->private->pgid_valid_mask & lpm) == 0)
343 			continue;
344 		pgid = &cdev->private->pgid[i];
345 		if (sch->opm & lpm) {
346 			if (pgid->inf.ps.state1 != SNID_STATE1_GROUPED)
347 				continue;
348 		} else {
349 			if (pgid->inf.ps.state1 != SNID_STATE1_UNGROUPED)
350 				continue;
351 		}
352 		if (cdev->private->flags.mpath) {
353 			if (pgid->inf.ps.state3 != SNID_STATE3_MULTI_PATH)
354 				continue;
355 		} else {
356 			if (pgid->inf.ps.state3 != SNID_STATE3_SINGLE_PATH)
357 				continue;
358 		}
359 		donepm |= lpm;
360 	}
361 
362 	return donepm;
363 }
364 
365 static void pgid_fill(struct ccw_device *cdev, struct pgid *pgid)
366 {
367 	int i;
368 
369 	for (i = 0; i < 8; i++)
370 		memcpy(&cdev->private->pgid[i], pgid, sizeof(struct pgid));
371 }
372 
373 /*
374  * Process SENSE PGID data and report result.
375  */
376 static void snid_done(struct ccw_device *cdev, int rc)
377 {
378 	struct ccw_dev_id *id = &cdev->private->dev_id;
379 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
380 	struct pgid *pgid;
381 	int mismatch = 0;
382 	u8 reserved = 0;
383 	u8 reset = 0;
384 	u8 donepm;
385 
386 	if (rc)
387 		goto out;
388 	pgid_analyze(cdev, &pgid, &mismatch, &reserved, &reset);
389 	if (reserved == cdev->private->pgid_valid_mask)
390 		rc = -EUSERS;
391 	else if (mismatch)
392 		rc = -EOPNOTSUPP;
393 	else {
394 		donepm = pgid_to_donepm(cdev);
395 		sch->vpm = donepm & sch->opm;
396 		cdev->private->pgid_reset_mask |= reset;
397 		cdev->private->pgid_todo_mask &=
398 			~(donepm | cdev->private->path_noirq_mask);
399 		pgid_fill(cdev, pgid);
400 	}
401 out:
402 	CIO_MSG_EVENT(2, "snid: device 0.%x.%04x: rc=%d pvm=%02x vpm=%02x "
403 		      "todo=%02x mism=%d rsvd=%02x reset=%02x\n", id->ssid,
404 		      id->devno, rc, cdev->private->pgid_valid_mask, sch->vpm,
405 		      cdev->private->pgid_todo_mask, mismatch, reserved, reset);
406 	switch (rc) {
407 	case 0:
408 		if (cdev->private->flags.pgid_unknown) {
409 			pgid_wipeout_start(cdev);
410 			return;
411 		}
412 		/* Anything left to do? */
413 		if (cdev->private->pgid_todo_mask == 0) {
414 			verify_done(cdev, sch->vpm == 0 ? -EACCES : 0);
415 			return;
416 		}
417 		/* Perform path-grouping. */
418 		spid_start(cdev);
419 		break;
420 	case -EOPNOTSUPP:
421 		/* Path-grouping not supported. */
422 		cdev->private->flags.pgroup = 0;
423 		cdev->private->flags.mpath = 0;
424 		verify_start(cdev);
425 		break;
426 	default:
427 		verify_done(cdev, rc);
428 	}
429 }
430 
431 /*
432  * Create channel program to perform a SENSE PGID on a single path.
433  */
434 static void snid_build_cp(struct ccw_device *cdev)
435 {
436 	struct ccw_request *req = &cdev->private->req;
437 	struct ccw1 *cp = cdev->private->iccws;
438 	int i = pathmask_to_pos(req->lpm);
439 
440 	/* Channel program setup. */
441 	cp->cmd_code	= CCW_CMD_SENSE_PGID;
442 	cp->cda		= (u32) (addr_t) &cdev->private->pgid[i];
443 	cp->count	= sizeof(struct pgid);
444 	cp->flags	= CCW_FLAG_SLI;
445 	req->cp		= cp;
446 }
447 
448 /*
449  * Perform SENSE PGID on a single path.
450  */
451 static void snid_do(struct ccw_device *cdev)
452 {
453 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
454 	struct ccw_request *req = &cdev->private->req;
455 	int ret;
456 
457 	req->lpm = lpm_adjust(req->lpm, sch->schib.pmcw.pam &
458 			      ~cdev->private->path_noirq_mask);
459 	if (!req->lpm)
460 		goto out_nopath;
461 	snid_build_cp(cdev);
462 	ccw_request_start(cdev);
463 	return;
464 
465 out_nopath:
466 	if (cdev->private->pgid_valid_mask)
467 		ret = 0;
468 	else if (cdev->private->path_noirq_mask)
469 		ret = -ETIME;
470 	else
471 		ret = -EACCES;
472 	snid_done(cdev, ret);
473 }
474 
475 /*
476  * Process SENSE PGID request result for single path.
477  */
478 static void snid_callback(struct ccw_device *cdev, void *data, int rc)
479 {
480 	struct ccw_request *req = &cdev->private->req;
481 
482 	switch (rc) {
483 	case 0:
484 		cdev->private->pgid_valid_mask |= req->lpm;
485 		break;
486 	case -ETIME:
487 		cdev->private->flags.pgid_unknown = 1;
488 		cdev->private->path_noirq_mask |= req->lpm;
489 		break;
490 	case -EACCES:
491 		cdev->private->path_notoper_mask |= req->lpm;
492 		break;
493 	default:
494 		goto err;
495 	}
496 	/* Continue on the next path. */
497 	req->lpm >>= 1;
498 	snid_do(cdev);
499 	return;
500 
501 err:
502 	snid_done(cdev, rc);
503 }
504 
505 /*
506  * Perform path verification.
507  */
508 static void verify_start(struct ccw_device *cdev)
509 {
510 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
511 	struct ccw_request *req = &cdev->private->req;
512 	struct ccw_dev_id *devid = &cdev->private->dev_id;
513 
514 	sch->vpm = 0;
515 	sch->lpm = sch->schib.pmcw.pam;
516 
517 	/* Initialize PGID data. */
518 	memset(cdev->private->pgid, 0, sizeof(cdev->private->pgid));
519 	cdev->private->pgid_valid_mask = 0;
520 	cdev->private->pgid_todo_mask = sch->schib.pmcw.pam;
521 	cdev->private->path_notoper_mask = 0;
522 
523 	/* Initialize request data. */
524 	memset(req, 0, sizeof(*req));
525 	req->timeout	= PGID_TIMEOUT;
526 	req->maxretries	= PGID_RETRIES;
527 	req->lpm	= 0x80;
528 	req->singlepath	= 1;
529 	if (cdev->private->flags.pgroup) {
530 		CIO_TRACE_EVENT(4, "snid");
531 		CIO_HEX_EVENT(4, devid, sizeof(*devid));
532 		req->callback	= snid_callback;
533 		snid_do(cdev);
534 	} else {
535 		CIO_TRACE_EVENT(4, "nop");
536 		CIO_HEX_EVENT(4, devid, sizeof(*devid));
537 		req->filter	= nop_filter;
538 		req->callback	= nop_callback;
539 		nop_do(cdev);
540 	}
541 }
542 
543 /**
544  * ccw_device_verify_start - perform path verification
545  * @cdev: ccw device
546  *
547  * Perform an I/O on each available channel path to @cdev to determine which
548  * paths are operational. The resulting path mask is stored in sch->vpm.
549  * If device options specify pathgrouping, establish a pathgroup for the
550  * operational paths. When finished, call ccw_device_verify_done with a
551  * return code specifying the result.
552  */
553 void ccw_device_verify_start(struct ccw_device *cdev)
554 {
555 	CIO_TRACE_EVENT(4, "vrfy");
556 	CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
557 	/*
558 	 * Initialize pathgroup and multipath state with target values.
559 	 * They may change in the course of path verification.
560 	 */
561 	cdev->private->flags.pgroup = cdev->private->options.pgroup;
562 	cdev->private->flags.mpath = cdev->private->options.mpath;
563 	cdev->private->flags.doverify = 0;
564 	cdev->private->path_noirq_mask = 0;
565 	verify_start(cdev);
566 }
567 
568 /*
569  * Process disband SET PGID request result.
570  */
571 static void disband_callback(struct ccw_device *cdev, void *data, int rc)
572 {
573 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
574 	struct ccw_dev_id *id = &cdev->private->dev_id;
575 
576 	if (rc)
577 		goto out;
578 	/* Ensure consistent multipathing state at device and channel. */
579 	cdev->private->flags.mpath = 0;
580 	if (sch->config.mp) {
581 		sch->config.mp = 0;
582 		rc = cio_commit_config(sch);
583 	}
584 out:
585 	CIO_MSG_EVENT(0, "disb: device 0.%x.%04x: rc=%d\n", id->ssid, id->devno,
586 		      rc);
587 	ccw_device_disband_done(cdev, rc);
588 }
589 
590 /**
591  * ccw_device_disband_start - disband pathgroup
592  * @cdev: ccw device
593  *
594  * Execute a SET PGID channel program on @cdev to disband a previously
595  * established pathgroup. When finished, call ccw_device_disband_done with
596  * a return code specifying the result.
597  */
598 void ccw_device_disband_start(struct ccw_device *cdev)
599 {
600 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
601 	struct ccw_request *req = &cdev->private->req;
602 	u8 fn;
603 
604 	CIO_TRACE_EVENT(4, "disb");
605 	CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
606 	/* Request setup. */
607 	memset(req, 0, sizeof(*req));
608 	req->timeout	= PGID_TIMEOUT;
609 	req->maxretries	= PGID_RETRIES;
610 	req->lpm	= sch->schib.pmcw.pam & sch->opm;
611 	req->singlepath	= 1;
612 	req->callback	= disband_callback;
613 	fn = SPID_FUNC_DISBAND;
614 	if (cdev->private->flags.mpath)
615 		fn |= SPID_FUNC_MULTI_PATH;
616 	spid_build_cp(cdev, fn);
617 	ccw_request_start(cdev);
618 }
619 
620 struct stlck_data {
621 	struct completion done;
622 	int rc;
623 };
624 
625 static void stlck_build_cp(struct ccw_device *cdev, void *buf1, void *buf2)
626 {
627 	struct ccw_request *req = &cdev->private->req;
628 	struct ccw1 *cp = cdev->private->iccws;
629 
630 	cp[0].cmd_code = CCW_CMD_STLCK;
631 	cp[0].cda = (u32) (addr_t) buf1;
632 	cp[0].count = 32;
633 	cp[0].flags = CCW_FLAG_CC;
634 	cp[1].cmd_code = CCW_CMD_RELEASE;
635 	cp[1].cda = (u32) (addr_t) buf2;
636 	cp[1].count = 32;
637 	cp[1].flags = 0;
638 	req->cp = cp;
639 }
640 
641 static void stlck_callback(struct ccw_device *cdev, void *data, int rc)
642 {
643 	struct stlck_data *sdata = data;
644 
645 	sdata->rc = rc;
646 	complete(&sdata->done);
647 }
648 
649 /**
650  * ccw_device_stlck_start - perform unconditional release
651  * @cdev: ccw device
652  * @data: data pointer to be passed to ccw_device_stlck_done
653  * @buf1: data pointer used in channel program
654  * @buf2: data pointer used in channel program
655  *
656  * Execute a channel program on @cdev to release an existing PGID reservation.
657  */
658 static void ccw_device_stlck_start(struct ccw_device *cdev, void *data,
659 				   void *buf1, void *buf2)
660 {
661 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
662 	struct ccw_request *req = &cdev->private->req;
663 
664 	CIO_TRACE_EVENT(4, "stlck");
665 	CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
666 	/* Request setup. */
667 	memset(req, 0, sizeof(*req));
668 	req->timeout	= PGID_TIMEOUT;
669 	req->maxretries	= PGID_RETRIES;
670 	req->lpm	= sch->schib.pmcw.pam & sch->opm;
671 	req->data	= data;
672 	req->callback	= stlck_callback;
673 	stlck_build_cp(cdev, buf1, buf2);
674 	ccw_request_start(cdev);
675 }
676 
677 /*
678  * Perform unconditional reserve + release.
679  */
680 int ccw_device_stlck(struct ccw_device *cdev)
681 {
682 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
683 	struct stlck_data data;
684 	u8 *buffer;
685 	int rc;
686 
687 	/* Check if steal lock operation is valid for this device. */
688 	if (cdev->drv) {
689 		if (!cdev->private->options.force)
690 			return -EINVAL;
691 	}
692 	buffer = kzalloc(64, GFP_DMA | GFP_KERNEL);
693 	if (!buffer)
694 		return -ENOMEM;
695 	init_completion(&data.done);
696 	data.rc = -EIO;
697 	spin_lock_irq(sch->lock);
698 	rc = cio_enable_subchannel(sch, (u32) (addr_t) sch);
699 	if (rc)
700 		goto out_unlock;
701 	/* Perform operation. */
702 	cdev->private->state = DEV_STATE_STEAL_LOCK;
703 	ccw_device_stlck_start(cdev, &data, &buffer[0], &buffer[32]);
704 	spin_unlock_irq(sch->lock);
705 	/* Wait for operation to finish. */
706 	if (wait_for_completion_interruptible(&data.done)) {
707 		/* Got a signal. */
708 		spin_lock_irq(sch->lock);
709 		ccw_request_cancel(cdev);
710 		spin_unlock_irq(sch->lock);
711 		wait_for_completion(&data.done);
712 	}
713 	rc = data.rc;
714 	/* Check results. */
715 	spin_lock_irq(sch->lock);
716 	cio_disable_subchannel(sch);
717 	cdev->private->state = DEV_STATE_BOXED;
718 out_unlock:
719 	spin_unlock_irq(sch->lock);
720 	kfree(buffer);
721 
722 	return rc;
723 }
724