drivers/s390/cio/device_pgid.c

   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 }