xref: /openbmc/linux/drivers/s390/cio/device_pgid.c (revision 6c33a6f4)
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->dma_area->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->dma_area->iccws;
138 	int i = pathmask_to_pos(req->lpm);
139 	struct pgid *pgid = &cdev->private->dma_area->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->dma_area->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->dma_area->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->dma_area->pgid[i], pgid,
372 		       sizeof(struct pgid));
373 }
374 
375 /*
376  * Process SENSE PGID data and report result.
377  */
378 static void snid_done(struct ccw_device *cdev, int rc)
379 {
380 	struct ccw_dev_id *id = &cdev->private->dev_id;
381 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
382 	struct pgid *pgid;
383 	int mismatch = 0;
384 	u8 reserved = 0;
385 	u8 reset = 0;
386 	u8 donepm;
387 
388 	if (rc)
389 		goto out;
390 	pgid_analyze(cdev, &pgid, &mismatch, &reserved, &reset);
391 	if (reserved == cdev->private->pgid_valid_mask)
392 		rc = -EUSERS;
393 	else if (mismatch)
394 		rc = -EOPNOTSUPP;
395 	else {
396 		donepm = pgid_to_donepm(cdev);
397 		sch->vpm = donepm & sch->opm;
398 		cdev->private->pgid_reset_mask |= reset;
399 		cdev->private->pgid_todo_mask &=
400 			~(donepm | cdev->private->path_noirq_mask);
401 		pgid_fill(cdev, pgid);
402 	}
403 out:
404 	CIO_MSG_EVENT(2, "snid: device 0.%x.%04x: rc=%d pvm=%02x vpm=%02x "
405 		      "todo=%02x mism=%d rsvd=%02x reset=%02x\n", id->ssid,
406 		      id->devno, rc, cdev->private->pgid_valid_mask, sch->vpm,
407 		      cdev->private->pgid_todo_mask, mismatch, reserved, reset);
408 	switch (rc) {
409 	case 0:
410 		if (cdev->private->flags.pgid_unknown) {
411 			pgid_wipeout_start(cdev);
412 			return;
413 		}
414 		/* Anything left to do? */
415 		if (cdev->private->pgid_todo_mask == 0) {
416 			verify_done(cdev, sch->vpm == 0 ? -EACCES : 0);
417 			return;
418 		}
419 		/* Perform path-grouping. */
420 		spid_start(cdev);
421 		break;
422 	case -EOPNOTSUPP:
423 		/* Path-grouping not supported. */
424 		cdev->private->flags.pgroup = 0;
425 		cdev->private->flags.mpath = 0;
426 		verify_start(cdev);
427 		break;
428 	default:
429 		verify_done(cdev, rc);
430 	}
431 }
432 
433 /*
434  * Create channel program to perform a SENSE PGID on a single path.
435  */
436 static void snid_build_cp(struct ccw_device *cdev)
437 {
438 	struct ccw_request *req = &cdev->private->req;
439 	struct ccw1 *cp = cdev->private->dma_area->iccws;
440 	int i = pathmask_to_pos(req->lpm);
441 
442 	/* Channel program setup. */
443 	cp->cmd_code	= CCW_CMD_SENSE_PGID;
444 	cp->cda		= (u32) (addr_t) &cdev->private->dma_area->pgid[i];
445 	cp->count	= sizeof(struct pgid);
446 	cp->flags	= CCW_FLAG_SLI;
447 	req->cp		= cp;
448 }
449 
450 /*
451  * Perform SENSE PGID on a single path.
452  */
453 static void snid_do(struct ccw_device *cdev)
454 {
455 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
456 	struct ccw_request *req = &cdev->private->req;
457 	int ret;
458 
459 	req->lpm = lpm_adjust(req->lpm, sch->schib.pmcw.pam &
460 			      ~cdev->private->path_noirq_mask);
461 	if (!req->lpm)
462 		goto out_nopath;
463 	snid_build_cp(cdev);
464 	ccw_request_start(cdev);
465 	return;
466 
467 out_nopath:
468 	if (cdev->private->pgid_valid_mask)
469 		ret = 0;
470 	else if (cdev->private->path_noirq_mask)
471 		ret = -ETIME;
472 	else
473 		ret = -EACCES;
474 	snid_done(cdev, ret);
475 }
476 
477 /*
478  * Process SENSE PGID request result for single path.
479  */
480 static void snid_callback(struct ccw_device *cdev, void *data, int rc)
481 {
482 	struct ccw_request *req = &cdev->private->req;
483 
484 	switch (rc) {
485 	case 0:
486 		cdev->private->pgid_valid_mask |= req->lpm;
487 		break;
488 	case -ETIME:
489 		cdev->private->flags.pgid_unknown = 1;
490 		cdev->private->path_noirq_mask |= req->lpm;
491 		break;
492 	case -EACCES:
493 		cdev->private->path_notoper_mask |= req->lpm;
494 		break;
495 	default:
496 		goto err;
497 	}
498 	/* Continue on the next path. */
499 	req->lpm >>= 1;
500 	snid_do(cdev);
501 	return;
502 
503 err:
504 	snid_done(cdev, rc);
505 }
506 
507 /*
508  * Perform path verification.
509  */
510 static void verify_start(struct ccw_device *cdev)
511 {
512 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
513 	struct ccw_request *req = &cdev->private->req;
514 	struct ccw_dev_id *devid = &cdev->private->dev_id;
515 
516 	sch->vpm = 0;
517 	sch->lpm = sch->schib.pmcw.pam;
518 
519 	/* Initialize PGID data. */
520 	memset(cdev->private->dma_area->pgid, 0,
521 	       sizeof(cdev->private->dma_area->pgid));
522 	cdev->private->pgid_valid_mask = 0;
523 	cdev->private->pgid_todo_mask = sch->schib.pmcw.pam;
524 	cdev->private->path_notoper_mask = 0;
525 
526 	/* Initialize request data. */
527 	memset(req, 0, sizeof(*req));
528 	req->timeout	= PGID_TIMEOUT;
529 	req->maxretries	= PGID_RETRIES;
530 	req->lpm	= 0x80;
531 	req->singlepath	= 1;
532 	if (cdev->private->flags.pgroup) {
533 		CIO_TRACE_EVENT(4, "snid");
534 		CIO_HEX_EVENT(4, devid, sizeof(*devid));
535 		req->callback	= snid_callback;
536 		snid_do(cdev);
537 	} else {
538 		CIO_TRACE_EVENT(4, "nop");
539 		CIO_HEX_EVENT(4, devid, sizeof(*devid));
540 		req->filter	= nop_filter;
541 		req->callback	= nop_callback;
542 		nop_do(cdev);
543 	}
544 }
545 
546 /**
547  * ccw_device_verify_start - perform path verification
548  * @cdev: ccw device
549  *
550  * Perform an I/O on each available channel path to @cdev to determine which
551  * paths are operational. The resulting path mask is stored in sch->vpm.
552  * If device options specify pathgrouping, establish a pathgroup for the
553  * operational paths. When finished, call ccw_device_verify_done with a
554  * return code specifying the result.
555  */
556 void ccw_device_verify_start(struct ccw_device *cdev)
557 {
558 	CIO_TRACE_EVENT(4, "vrfy");
559 	CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
560 	/*
561 	 * Initialize pathgroup and multipath state with target values.
562 	 * They may change in the course of path verification.
563 	 */
564 	cdev->private->flags.pgroup = cdev->private->options.pgroup;
565 	cdev->private->flags.mpath = cdev->private->options.mpath;
566 	cdev->private->flags.doverify = 0;
567 	cdev->private->path_noirq_mask = 0;
568 	verify_start(cdev);
569 }
570 
571 /*
572  * Process disband SET PGID request result.
573  */
574 static void disband_callback(struct ccw_device *cdev, void *data, int rc)
575 {
576 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
577 	struct ccw_dev_id *id = &cdev->private->dev_id;
578 
579 	if (rc)
580 		goto out;
581 	/* Ensure consistent multipathing state at device and channel. */
582 	cdev->private->flags.mpath = 0;
583 	if (sch->config.mp) {
584 		sch->config.mp = 0;
585 		rc = cio_commit_config(sch);
586 	}
587 out:
588 	CIO_MSG_EVENT(0, "disb: device 0.%x.%04x: rc=%d\n", id->ssid, id->devno,
589 		      rc);
590 	ccw_device_disband_done(cdev, rc);
591 }
592 
593 /**
594  * ccw_device_disband_start - disband pathgroup
595  * @cdev: ccw device
596  *
597  * Execute a SET PGID channel program on @cdev to disband a previously
598  * established pathgroup. When finished, call ccw_device_disband_done with
599  * a return code specifying the result.
600  */
601 void ccw_device_disband_start(struct ccw_device *cdev)
602 {
603 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
604 	struct ccw_request *req = &cdev->private->req;
605 	u8 fn;
606 
607 	CIO_TRACE_EVENT(4, "disb");
608 	CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
609 	/* Request setup. */
610 	memset(req, 0, sizeof(*req));
611 	req->timeout	= PGID_TIMEOUT;
612 	req->maxretries	= PGID_RETRIES;
613 	req->lpm	= sch->schib.pmcw.pam & sch->opm;
614 	req->singlepath	= 1;
615 	req->callback	= disband_callback;
616 	fn = SPID_FUNC_DISBAND;
617 	if (cdev->private->flags.mpath)
618 		fn |= SPID_FUNC_MULTI_PATH;
619 	spid_build_cp(cdev, fn);
620 	ccw_request_start(cdev);
621 }
622 
623 struct stlck_data {
624 	struct completion done;
625 	int rc;
626 };
627 
628 static void stlck_build_cp(struct ccw_device *cdev, void *buf1, void *buf2)
629 {
630 	struct ccw_request *req = &cdev->private->req;
631 	struct ccw1 *cp = cdev->private->dma_area->iccws;
632 
633 	cp[0].cmd_code = CCW_CMD_STLCK;
634 	cp[0].cda = (u32) (addr_t) buf1;
635 	cp[0].count = 32;
636 	cp[0].flags = CCW_FLAG_CC;
637 	cp[1].cmd_code = CCW_CMD_RELEASE;
638 	cp[1].cda = (u32) (addr_t) buf2;
639 	cp[1].count = 32;
640 	cp[1].flags = 0;
641 	req->cp = cp;
642 }
643 
644 static void stlck_callback(struct ccw_device *cdev, void *data, int rc)
645 {
646 	struct stlck_data *sdata = data;
647 
648 	sdata->rc = rc;
649 	complete(&sdata->done);
650 }
651 
652 /**
653  * ccw_device_stlck_start - perform unconditional release
654  * @cdev: ccw device
655  * @data: data pointer to be passed to ccw_device_stlck_done
656  * @buf1: data pointer used in channel program
657  * @buf2: data pointer used in channel program
658  *
659  * Execute a channel program on @cdev to release an existing PGID reservation.
660  */
661 static void ccw_device_stlck_start(struct ccw_device *cdev, void *data,
662 				   void *buf1, void *buf2)
663 {
664 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
665 	struct ccw_request *req = &cdev->private->req;
666 
667 	CIO_TRACE_EVENT(4, "stlck");
668 	CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
669 	/* Request setup. */
670 	memset(req, 0, sizeof(*req));
671 	req->timeout	= PGID_TIMEOUT;
672 	req->maxretries	= PGID_RETRIES;
673 	req->lpm	= sch->schib.pmcw.pam & sch->opm;
674 	req->data	= data;
675 	req->callback	= stlck_callback;
676 	stlck_build_cp(cdev, buf1, buf2);
677 	ccw_request_start(cdev);
678 }
679 
680 /*
681  * Perform unconditional reserve + release.
682  */
683 int ccw_device_stlck(struct ccw_device *cdev)
684 {
685 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
686 	struct stlck_data data;
687 	u8 *buffer;
688 	int rc;
689 
690 	/* Check if steal lock operation is valid for this device. */
691 	if (cdev->drv) {
692 		if (!cdev->private->options.force)
693 			return -EINVAL;
694 	}
695 	buffer = kzalloc(64, GFP_DMA | GFP_KERNEL);
696 	if (!buffer)
697 		return -ENOMEM;
698 	init_completion(&data.done);
699 	data.rc = -EIO;
700 	spin_lock_irq(sch->lock);
701 	rc = cio_enable_subchannel(sch, (u32) (addr_t) sch);
702 	if (rc)
703 		goto out_unlock;
704 	/* Perform operation. */
705 	cdev->private->state = DEV_STATE_STEAL_LOCK;
706 	ccw_device_stlck_start(cdev, &data, &buffer[0], &buffer[32]);
707 	spin_unlock_irq(sch->lock);
708 	/* Wait for operation to finish. */
709 	if (wait_for_completion_interruptible(&data.done)) {
710 		/* Got a signal. */
711 		spin_lock_irq(sch->lock);
712 		ccw_request_cancel(cdev);
713 		spin_unlock_irq(sch->lock);
714 		wait_for_completion(&data.done);
715 	}
716 	rc = data.rc;
717 	/* Check results. */
718 	spin_lock_irq(sch->lock);
719 	cio_disable_subchannel(sch);
720 	cdev->private->state = DEV_STATE_BOXED;
721 out_unlock:
722 	spin_unlock_irq(sch->lock);
723 	kfree(buffer);
724 
725 	return rc;
726 }
727