xref: /openbmc/linux/drivers/s390/cio/device_pgid.c (revision 2359ccdd)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  CCW device PGID and path verification I/O handling.
4  *
5  *    Copyright IBM Corp. 2002, 2009
6  *    Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
7  *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
8  *		 Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
9  */
10 
11 #include <linux/kernel.h>
12 #include <linux/string.h>
13 #include <linux/bitops.h>
14 #include <linux/types.h>
15 #include <linux/errno.h>
16 #include <linux/slab.h>
17 #include <asm/ccwdev.h>
18 #include <asm/cio.h>
19 
20 #include "cio.h"
21 #include "cio_debug.h"
22 #include "device.h"
23 #include "io_sch.h"
24 
25 #define PGID_RETRIES	256
26 #define PGID_TIMEOUT	(10 * HZ)
27 
28 static void verify_start(struct ccw_device *cdev);
29 
30 /*
31  * Process path verification data and report result.
32  */
33 static void verify_done(struct ccw_device *cdev, int rc)
34 {
35 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
36 	struct ccw_dev_id *id = &cdev->private->dev_id;
37 	int mpath = cdev->private->flags.mpath;
38 	int pgroup = cdev->private->flags.pgroup;
39 
40 	if (rc)
41 		goto out;
42 	/* Ensure consistent multipathing state at device and channel. */
43 	if (sch->config.mp != mpath) {
44 		sch->config.mp = mpath;
45 		rc = cio_commit_config(sch);
46 	}
47 out:
48 	CIO_MSG_EVENT(2, "vrfy: device 0.%x.%04x: rc=%d pgroup=%d mpath=%d "
49 			 "vpm=%02x\n", id->ssid, id->devno, rc, pgroup, mpath,
50 			 sch->vpm);
51 	ccw_device_verify_done(cdev, rc);
52 }
53 
54 /*
55  * Create channel program to perform a NOOP.
56  */
57 static void nop_build_cp(struct ccw_device *cdev)
58 {
59 	struct ccw_request *req = &cdev->private->req;
60 	struct ccw1 *cp = cdev->private->iccws;
61 
62 	cp->cmd_code	= CCW_CMD_NOOP;
63 	cp->cda		= 0;
64 	cp->count	= 0;
65 	cp->flags	= CCW_FLAG_SLI;
66 	req->cp		= cp;
67 }
68 
69 /*
70  * Perform NOOP on a single path.
71  */
72 static void nop_do(struct ccw_device *cdev)
73 {
74 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
75 	struct ccw_request *req = &cdev->private->req;
76 
77 	req->lpm = lpm_adjust(req->lpm, sch->schib.pmcw.pam & sch->opm &
78 			      ~cdev->private->path_noirq_mask);
79 	if (!req->lpm)
80 		goto out_nopath;
81 	nop_build_cp(cdev);
82 	ccw_request_start(cdev);
83 	return;
84 
85 out_nopath:
86 	verify_done(cdev, sch->vpm ? 0 : -EACCES);
87 }
88 
89 /*
90  * Adjust NOOP I/O status.
91  */
92 static enum io_status nop_filter(struct ccw_device *cdev, void *data,
93 				 struct irb *irb, enum io_status status)
94 {
95 	/* Only subchannel status might indicate a path error. */
96 	if (status == IO_STATUS_ERROR && irb->scsw.cmd.cstat == 0)
97 		return IO_DONE;
98 	return status;
99 }
100 
101 /*
102  * Process NOOP request result for a single path.
103  */
104 static void nop_callback(struct ccw_device *cdev, void *data, int rc)
105 {
106 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
107 	struct ccw_request *req = &cdev->private->req;
108 
109 	switch (rc) {
110 	case 0:
111 		sch->vpm |= req->lpm;
112 		break;
113 	case -ETIME:
114 		cdev->private->path_noirq_mask |= req->lpm;
115 		break;
116 	case -EACCES:
117 		cdev->private->path_notoper_mask |= req->lpm;
118 		break;
119 	default:
120 		goto err;
121 	}
122 	/* Continue on the next path. */
123 	req->lpm >>= 1;
124 	nop_do(cdev);
125 	return;
126 
127 err:
128 	verify_done(cdev, rc);
129 }
130 
131 /*
132  * Create channel program to perform SET PGID on a single path.
133  */
134 static void spid_build_cp(struct ccw_device *cdev, u8 fn)
135 {
136 	struct ccw_request *req = &cdev->private->req;
137 	struct ccw1 *cp = cdev->private->iccws;
138 	int i = pathmask_to_pos(req->lpm);
139 	struct pgid *pgid = &cdev->private->pgid[i];
140 
141 	pgid->inf.fc	= fn;
142 	cp->cmd_code	= CCW_CMD_SET_PGID;
143 	cp->cda		= (u32) (addr_t) pgid;
144 	cp->count	= sizeof(*pgid);
145 	cp->flags	= CCW_FLAG_SLI;
146 	req->cp		= cp;
147 }
148 
149 static void pgid_wipeout_callback(struct ccw_device *cdev, void *data, int rc)
150 {
151 	if (rc) {
152 		/* We don't know the path groups' state. Abort. */
153 		verify_done(cdev, rc);
154 		return;
155 	}
156 	/*
157 	 * Path groups have been reset. Restart path verification but
158 	 * leave paths in path_noirq_mask out.
159 	 */
160 	cdev->private->flags.pgid_unknown = 0;
161 	verify_start(cdev);
162 }
163 
164 /*
165  * Reset pathgroups and restart path verification, leave unusable paths out.
166  */
167 static void pgid_wipeout_start(struct ccw_device *cdev)
168 {
169 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
170 	struct ccw_dev_id *id = &cdev->private->dev_id;
171 	struct ccw_request *req = &cdev->private->req;
172 	u8 fn;
173 
174 	CIO_MSG_EVENT(2, "wipe: device 0.%x.%04x: pvm=%02x nim=%02x\n",
175 		      id->ssid, id->devno, cdev->private->pgid_valid_mask,
176 		      cdev->private->path_noirq_mask);
177 
178 	/* Initialize request data. */
179 	memset(req, 0, sizeof(*req));
180 	req->timeout	= PGID_TIMEOUT;
181 	req->maxretries	= PGID_RETRIES;
182 	req->lpm	= sch->schib.pmcw.pam;
183 	req->callback	= pgid_wipeout_callback;
184 	fn = SPID_FUNC_DISBAND;
185 	if (cdev->private->flags.mpath)
186 		fn |= SPID_FUNC_MULTI_PATH;
187 	spid_build_cp(cdev, fn);
188 	ccw_request_start(cdev);
189 }
190 
191 /*
192  * Perform establish/resign SET PGID on a single path.
193  */
194 static void spid_do(struct ccw_device *cdev)
195 {
196 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
197 	struct ccw_request *req = &cdev->private->req;
198 	u8 fn;
199 
200 	/* Use next available path that is not already in correct state. */
201 	req->lpm = lpm_adjust(req->lpm, cdev->private->pgid_todo_mask);
202 	if (!req->lpm)
203 		goto out_nopath;
204 	/* Channel program setup. */
205 	if (req->lpm & sch->opm)
206 		fn = SPID_FUNC_ESTABLISH;
207 	else
208 		fn = SPID_FUNC_RESIGN;
209 	if (cdev->private->flags.mpath)
210 		fn |= SPID_FUNC_MULTI_PATH;
211 	spid_build_cp(cdev, fn);
212 	ccw_request_start(cdev);
213 	return;
214 
215 out_nopath:
216 	if (cdev->private->flags.pgid_unknown) {
217 		/* At least one SPID could be partially done. */
218 		pgid_wipeout_start(cdev);
219 		return;
220 	}
221 	verify_done(cdev, sch->vpm ? 0 : -EACCES);
222 }
223 
224 /*
225  * Process SET PGID request result for a single path.
226  */
227 static void spid_callback(struct ccw_device *cdev, void *data, int rc)
228 {
229 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
230 	struct ccw_request *req = &cdev->private->req;
231 
232 	switch (rc) {
233 	case 0:
234 		sch->vpm |= req->lpm & sch->opm;
235 		break;
236 	case -ETIME:
237 		cdev->private->flags.pgid_unknown = 1;
238 		cdev->private->path_noirq_mask |= req->lpm;
239 		break;
240 	case -EACCES:
241 		cdev->private->path_notoper_mask |= req->lpm;
242 		break;
243 	case -EOPNOTSUPP:
244 		if (cdev->private->flags.mpath) {
245 			/* Try without multipathing. */
246 			cdev->private->flags.mpath = 0;
247 			goto out_restart;
248 		}
249 		/* Try without pathgrouping. */
250 		cdev->private->flags.pgroup = 0;
251 		goto out_restart;
252 	default:
253 		goto err;
254 	}
255 	req->lpm >>= 1;
256 	spid_do(cdev);
257 	return;
258 
259 out_restart:
260 	verify_start(cdev);
261 	return;
262 err:
263 	verify_done(cdev, rc);
264 }
265 
266 static void spid_start(struct ccw_device *cdev)
267 {
268 	struct ccw_request *req = &cdev->private->req;
269 
270 	/* Initialize request data. */
271 	memset(req, 0, sizeof(*req));
272 	req->timeout	= PGID_TIMEOUT;
273 	req->maxretries	= PGID_RETRIES;
274 	req->lpm	= 0x80;
275 	req->singlepath	= 1;
276 	req->callback	= spid_callback;
277 	spid_do(cdev);
278 }
279 
280 static int pgid_is_reset(struct pgid *p)
281 {
282 	char *c;
283 
284 	for (c = (char *)p + 1; c < (char *)(p + 1); c++) {
285 		if (*c != 0)
286 			return 0;
287 	}
288 	return 1;
289 }
290 
291 static int pgid_cmp(struct pgid *p1, struct pgid *p2)
292 {
293 	return memcmp((char *) p1 + 1, (char *) p2 + 1,
294 		      sizeof(struct pgid) - 1);
295 }
296 
297 /*
298  * Determine pathgroup state from PGID data.
299  */
300 static void pgid_analyze(struct ccw_device *cdev, struct pgid **p,
301 			 int *mismatch, u8 *reserved, u8 *reset)
302 {
303 	struct pgid *pgid = &cdev->private->pgid[0];
304 	struct pgid *first = NULL;
305 	int lpm;
306 	int i;
307 
308 	*mismatch = 0;
309 	*reserved = 0;
310 	*reset = 0;
311 	for (i = 0, lpm = 0x80; i < 8; i++, pgid++, lpm >>= 1) {
312 		if ((cdev->private->pgid_valid_mask & lpm) == 0)
313 			continue;
314 		if (pgid->inf.ps.state2 == SNID_STATE2_RESVD_ELSE)
315 			*reserved |= lpm;
316 		if (pgid_is_reset(pgid)) {
317 			*reset |= lpm;
318 			continue;
319 		}
320 		if (!first) {
321 			first = pgid;
322 			continue;
323 		}
324 		if (pgid_cmp(pgid, first) != 0)
325 			*mismatch = 1;
326 	}
327 	if (!first)
328 		first = &channel_subsystems[0]->global_pgid;
329 	*p = first;
330 }
331 
332 static u8 pgid_to_donepm(struct ccw_device *cdev)
333 {
334 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
335 	struct pgid *pgid;
336 	int i;
337 	int lpm;
338 	u8 donepm = 0;
339 
340 	/* Set bits for paths which are already in the target state. */
341 	for (i = 0; i < 8; i++) {
342 		lpm = 0x80 >> i;
343 		if ((cdev->private->pgid_valid_mask & lpm) == 0)
344 			continue;
345 		pgid = &cdev->private->pgid[i];
346 		if (sch->opm & lpm) {
347 			if (pgid->inf.ps.state1 != SNID_STATE1_GROUPED)
348 				continue;
349 		} else {
350 			if (pgid->inf.ps.state1 != SNID_STATE1_UNGROUPED)
351 				continue;
352 		}
353 		if (cdev->private->flags.mpath) {
354 			if (pgid->inf.ps.state3 != SNID_STATE3_MULTI_PATH)
355 				continue;
356 		} else {
357 			if (pgid->inf.ps.state3 != SNID_STATE3_SINGLE_PATH)
358 				continue;
359 		}
360 		donepm |= lpm;
361 	}
362 
363 	return donepm;
364 }
365 
366 static void pgid_fill(struct ccw_device *cdev, struct pgid *pgid)
367 {
368 	int i;
369 
370 	for (i = 0; i < 8; i++)
371 		memcpy(&cdev->private->pgid[i], pgid, sizeof(struct pgid));
372 }
373 
374 /*
375  * Process SENSE PGID data and report result.
376  */
377 static void snid_done(struct ccw_device *cdev, int rc)
378 {
379 	struct ccw_dev_id *id = &cdev->private->dev_id;
380 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
381 	struct pgid *pgid;
382 	int mismatch = 0;
383 	u8 reserved = 0;
384 	u8 reset = 0;
385 	u8 donepm;
386 
387 	if (rc)
388 		goto out;
389 	pgid_analyze(cdev, &pgid, &mismatch, &reserved, &reset);
390 	if (reserved == cdev->private->pgid_valid_mask)
391 		rc = -EUSERS;
392 	else if (mismatch)
393 		rc = -EOPNOTSUPP;
394 	else {
395 		donepm = pgid_to_donepm(cdev);
396 		sch->vpm = donepm & sch->opm;
397 		cdev->private->pgid_reset_mask |= reset;
398 		cdev->private->pgid_todo_mask &=
399 			~(donepm | cdev->private->path_noirq_mask);
400 		pgid_fill(cdev, pgid);
401 	}
402 out:
403 	CIO_MSG_EVENT(2, "snid: device 0.%x.%04x: rc=%d pvm=%02x vpm=%02x "
404 		      "todo=%02x mism=%d rsvd=%02x reset=%02x\n", id->ssid,
405 		      id->devno, rc, cdev->private->pgid_valid_mask, sch->vpm,
406 		      cdev->private->pgid_todo_mask, mismatch, reserved, reset);
407 	switch (rc) {
408 	case 0:
409 		if (cdev->private->flags.pgid_unknown) {
410 			pgid_wipeout_start(cdev);
411 			return;
412 		}
413 		/* Anything left to do? */
414 		if (cdev->private->pgid_todo_mask == 0) {
415 			verify_done(cdev, sch->vpm == 0 ? -EACCES : 0);
416 			return;
417 		}
418 		/* Perform path-grouping. */
419 		spid_start(cdev);
420 		break;
421 	case -EOPNOTSUPP:
422 		/* Path-grouping not supported. */
423 		cdev->private->flags.pgroup = 0;
424 		cdev->private->flags.mpath = 0;
425 		verify_start(cdev);
426 		break;
427 	default:
428 		verify_done(cdev, rc);
429 	}
430 }
431 
432 /*
433  * Create channel program to perform a SENSE PGID on a single path.
434  */
435 static void snid_build_cp(struct ccw_device *cdev)
436 {
437 	struct ccw_request *req = &cdev->private->req;
438 	struct ccw1 *cp = cdev->private->iccws;
439 	int i = pathmask_to_pos(req->lpm);
440 
441 	/* Channel program setup. */
442 	cp->cmd_code	= CCW_CMD_SENSE_PGID;
443 	cp->cda		= (u32) (addr_t) &cdev->private->pgid[i];
444 	cp->count	= sizeof(struct pgid);
445 	cp->flags	= CCW_FLAG_SLI;
446 	req->cp		= cp;
447 }
448 
449 /*
450  * Perform SENSE PGID on a single path.
451  */
452 static void snid_do(struct ccw_device *cdev)
453 {
454 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
455 	struct ccw_request *req = &cdev->private->req;
456 	int ret;
457 
458 	req->lpm = lpm_adjust(req->lpm, sch->schib.pmcw.pam &
459 			      ~cdev->private->path_noirq_mask);
460 	if (!req->lpm)
461 		goto out_nopath;
462 	snid_build_cp(cdev);
463 	ccw_request_start(cdev);
464 	return;
465 
466 out_nopath:
467 	if (cdev->private->pgid_valid_mask)
468 		ret = 0;
469 	else if (cdev->private->path_noirq_mask)
470 		ret = -ETIME;
471 	else
472 		ret = -EACCES;
473 	snid_done(cdev, ret);
474 }
475 
476 /*
477  * Process SENSE PGID request result for single path.
478  */
479 static void snid_callback(struct ccw_device *cdev, void *data, int rc)
480 {
481 	struct ccw_request *req = &cdev->private->req;
482 
483 	switch (rc) {
484 	case 0:
485 		cdev->private->pgid_valid_mask |= req->lpm;
486 		break;
487 	case -ETIME:
488 		cdev->private->flags.pgid_unknown = 1;
489 		cdev->private->path_noirq_mask |= req->lpm;
490 		break;
491 	case -EACCES:
492 		cdev->private->path_notoper_mask |= req->lpm;
493 		break;
494 	default:
495 		goto err;
496 	}
497 	/* Continue on the next path. */
498 	req->lpm >>= 1;
499 	snid_do(cdev);
500 	return;
501 
502 err:
503 	snid_done(cdev, rc);
504 }
505 
506 /*
507  * Perform path verification.
508  */
509 static void verify_start(struct ccw_device *cdev)
510 {
511 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
512 	struct ccw_request *req = &cdev->private->req;
513 	struct ccw_dev_id *devid = &cdev->private->dev_id;
514 
515 	sch->vpm = 0;
516 	sch->lpm = sch->schib.pmcw.pam;
517 
518 	/* Initialize PGID data. */
519 	memset(cdev->private->pgid, 0, sizeof(cdev->private->pgid));
520 	cdev->private->pgid_valid_mask = 0;
521 	cdev->private->pgid_todo_mask = sch->schib.pmcw.pam;
522 	cdev->private->path_notoper_mask = 0;
523 
524 	/* Initialize request data. */
525 	memset(req, 0, sizeof(*req));
526 	req->timeout	= PGID_TIMEOUT;
527 	req->maxretries	= PGID_RETRIES;
528 	req->lpm	= 0x80;
529 	req->singlepath	= 1;
530 	if (cdev->private->flags.pgroup) {
531 		CIO_TRACE_EVENT(4, "snid");
532 		CIO_HEX_EVENT(4, devid, sizeof(*devid));
533 		req->callback	= snid_callback;
534 		snid_do(cdev);
535 	} else {
536 		CIO_TRACE_EVENT(4, "nop");
537 		CIO_HEX_EVENT(4, devid, sizeof(*devid));
538 		req->filter	= nop_filter;
539 		req->callback	= nop_callback;
540 		nop_do(cdev);
541 	}
542 }
543 
544 /**
545  * ccw_device_verify_start - perform path verification
546  * @cdev: ccw device
547  *
548  * Perform an I/O on each available channel path to @cdev to determine which
549  * paths are operational. The resulting path mask is stored in sch->vpm.
550  * If device options specify pathgrouping, establish a pathgroup for the
551  * operational paths. When finished, call ccw_device_verify_done with a
552  * return code specifying the result.
553  */
554 void ccw_device_verify_start(struct ccw_device *cdev)
555 {
556 	CIO_TRACE_EVENT(4, "vrfy");
557 	CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
558 	/*
559 	 * Initialize pathgroup and multipath state with target values.
560 	 * They may change in the course of path verification.
561 	 */
562 	cdev->private->flags.pgroup = cdev->private->options.pgroup;
563 	cdev->private->flags.mpath = cdev->private->options.mpath;
564 	cdev->private->flags.doverify = 0;
565 	cdev->private->path_noirq_mask = 0;
566 	verify_start(cdev);
567 }
568 
569 /*
570  * Process disband SET PGID request result.
571  */
572 static void disband_callback(struct ccw_device *cdev, void *data, int rc)
573 {
574 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
575 	struct ccw_dev_id *id = &cdev->private->dev_id;
576 
577 	if (rc)
578 		goto out;
579 	/* Ensure consistent multipathing state at device and channel. */
580 	cdev->private->flags.mpath = 0;
581 	if (sch->config.mp) {
582 		sch->config.mp = 0;
583 		rc = cio_commit_config(sch);
584 	}
585 out:
586 	CIO_MSG_EVENT(0, "disb: device 0.%x.%04x: rc=%d\n", id->ssid, id->devno,
587 		      rc);
588 	ccw_device_disband_done(cdev, rc);
589 }
590 
591 /**
592  * ccw_device_disband_start - disband pathgroup
593  * @cdev: ccw device
594  *
595  * Execute a SET PGID channel program on @cdev to disband a previously
596  * established pathgroup. When finished, call ccw_device_disband_done with
597  * a return code specifying the result.
598  */
599 void ccw_device_disband_start(struct ccw_device *cdev)
600 {
601 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
602 	struct ccw_request *req = &cdev->private->req;
603 	u8 fn;
604 
605 	CIO_TRACE_EVENT(4, "disb");
606 	CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
607 	/* Request setup. */
608 	memset(req, 0, sizeof(*req));
609 	req->timeout	= PGID_TIMEOUT;
610 	req->maxretries	= PGID_RETRIES;
611 	req->lpm	= sch->schib.pmcw.pam & sch->opm;
612 	req->singlepath	= 1;
613 	req->callback	= disband_callback;
614 	fn = SPID_FUNC_DISBAND;
615 	if (cdev->private->flags.mpath)
616 		fn |= SPID_FUNC_MULTI_PATH;
617 	spid_build_cp(cdev, fn);
618 	ccw_request_start(cdev);
619 }
620 
621 struct stlck_data {
622 	struct completion done;
623 	int rc;
624 };
625 
626 static void stlck_build_cp(struct ccw_device *cdev, void *buf1, void *buf2)
627 {
628 	struct ccw_request *req = &cdev->private->req;
629 	struct ccw1 *cp = cdev->private->iccws;
630 
631 	cp[0].cmd_code = CCW_CMD_STLCK;
632 	cp[0].cda = (u32) (addr_t) buf1;
633 	cp[0].count = 32;
634 	cp[0].flags = CCW_FLAG_CC;
635 	cp[1].cmd_code = CCW_CMD_RELEASE;
636 	cp[1].cda = (u32) (addr_t) buf2;
637 	cp[1].count = 32;
638 	cp[1].flags = 0;
639 	req->cp = cp;
640 }
641 
642 static void stlck_callback(struct ccw_device *cdev, void *data, int rc)
643 {
644 	struct stlck_data *sdata = data;
645 
646 	sdata->rc = rc;
647 	complete(&sdata->done);
648 }
649 
650 /**
651  * ccw_device_stlck_start - perform unconditional release
652  * @cdev: ccw device
653  * @data: data pointer to be passed to ccw_device_stlck_done
654  * @buf1: data pointer used in channel program
655  * @buf2: data pointer used in channel program
656  *
657  * Execute a channel program on @cdev to release an existing PGID reservation.
658  */
659 static void ccw_device_stlck_start(struct ccw_device *cdev, void *data,
660 				   void *buf1, void *buf2)
661 {
662 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
663 	struct ccw_request *req = &cdev->private->req;
664 
665 	CIO_TRACE_EVENT(4, "stlck");
666 	CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
667 	/* Request setup. */
668 	memset(req, 0, sizeof(*req));
669 	req->timeout	= PGID_TIMEOUT;
670 	req->maxretries	= PGID_RETRIES;
671 	req->lpm	= sch->schib.pmcw.pam & sch->opm;
672 	req->data	= data;
673 	req->callback	= stlck_callback;
674 	stlck_build_cp(cdev, buf1, buf2);
675 	ccw_request_start(cdev);
676 }
677 
678 /*
679  * Perform unconditional reserve + release.
680  */
681 int ccw_device_stlck(struct ccw_device *cdev)
682 {
683 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
684 	struct stlck_data data;
685 	u8 *buffer;
686 	int rc;
687 
688 	/* Check if steal lock operation is valid for this device. */
689 	if (cdev->drv) {
690 		if (!cdev->private->options.force)
691 			return -EINVAL;
692 	}
693 	buffer = kzalloc(64, GFP_DMA | GFP_KERNEL);
694 	if (!buffer)
695 		return -ENOMEM;
696 	init_completion(&data.done);
697 	data.rc = -EIO;
698 	spin_lock_irq(sch->lock);
699 	rc = cio_enable_subchannel(sch, (u32) (addr_t) sch);
700 	if (rc)
701 		goto out_unlock;
702 	/* Perform operation. */
703 	cdev->private->state = DEV_STATE_STEAL_LOCK;
704 	ccw_device_stlck_start(cdev, &data, &buffer[0], &buffer[32]);
705 	spin_unlock_irq(sch->lock);
706 	/* Wait for operation to finish. */
707 	if (wait_for_completion_interruptible(&data.done)) {
708 		/* Got a signal. */
709 		spin_lock_irq(sch->lock);
710 		ccw_request_cancel(cdev);
711 		spin_unlock_irq(sch->lock);
712 		wait_for_completion(&data.done);
713 	}
714 	rc = data.rc;
715 	/* Check results. */
716 	spin_lock_irq(sch->lock);
717 	cio_disable_subchannel(sch);
718 	cdev->private->state = DEV_STATE_BOXED;
719 out_unlock:
720 	spin_unlock_irq(sch->lock);
721 	kfree(buffer);
722 
723 	return rc;
724 }
725