drivers/s390/block/dasd_fba.c

   1 /*
   2  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
   3  * Bugreports.to..: <Linux390@de.ibm.com>
   4  * Copyright IBM Corp. 1999, 2009
   5  */
   6
   7 #define KMSG_COMPONENT "dasd-fba"
   8
   9 #include <linux/stddef.h>
  10 #include <linux/kernel.h>
  11 #include <asm/debug.h>
  12
  13 #include <linux/slab.h>
  14 #include <linux/hdreg.h>        /* HDIO_GETGEO                      */
  15 #include <linux/bio.h>
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18
  19 #include <asm/idals.h>
  20 #include <asm/ebcdic.h>
  21 #include <asm/io.h>
  22 #include <asm/ccwdev.h>
  23
  24 #include "dasd_int.h"
  25 #include "dasd_fba.h"
  26
  27 #ifdef PRINTK_HEADER
  28 #undef PRINTK_HEADER
  29 #endif                          /* PRINTK_HEADER */
  30 #define PRINTK_HEADER "dasd(fba):"
  31
  32 #define FBA_DEFAULT_RETRIES 32
  33
  34 #define DASD_FBA_CCW_WRITE 0x41
  35 #define DASD_FBA_CCW_READ 0x42
  36 #define DASD_FBA_CCW_LOCATE 0x43
  37 #define DASD_FBA_CCW_DEFINE_EXTENT 0x63
  38
  39 MODULE_LICENSE("GPL");
  40
  41 static struct dasd_discipline dasd_fba_discipline;
  42
  43 struct dasd_fba_private {
  44         struct dasd_fba_characteristics rdc_data;
  45 };
  46
  47 static struct ccw_device_id dasd_fba_ids[] = {
  48         { CCW_DEVICE_DEVTYPE (0x6310, 0, 0x9336, 0), .driver_info = 0x1},
  49         { CCW_DEVICE_DEVTYPE (0x3880, 0, 0x3370, 0), .driver_info = 0x2},
  50         { /* end of list */ },
  51 };
  52
  53 MODULE_DEVICE_TABLE(ccw, dasd_fba_ids);
  54
  55 static struct ccw_driver dasd_fba_driver; /* see below */
  56 static int
  57 dasd_fba_probe(struct ccw_device *cdev)
  58 {
  59         return dasd_generic_probe(cdev, &dasd_fba_discipline);
  60 }
  61
  62 static int
  63 dasd_fba_set_online(struct ccw_device *cdev)
  64 {
  65         return dasd_generic_set_online(cdev, &dasd_fba_discipline);
  66 }
  67
  68 static struct ccw_driver dasd_fba_driver = {
  69         .driver = {
  70                 .name   = "dasd-fba",
  71                 .owner  = THIS_MODULE,
  72         },
  73         .ids         = dasd_fba_ids,
  74         .probe       = dasd_fba_probe,
  75         .remove      = dasd_generic_remove,
  76         .set_offline = dasd_generic_set_offline,
  77         .set_online  = dasd_fba_set_online,
  78         .notify      = dasd_generic_notify,
  79         .path_event  = dasd_generic_path_event,
  80         .freeze      = dasd_generic_pm_freeze,
  81         .thaw        = dasd_generic_restore_device,
  82         .restore     = dasd_generic_restore_device,
  83         .int_class   = IRQIO_DAS,
  84 };
  85
  86 static void
  87 define_extent(struct ccw1 * ccw, struct DE_fba_data *data, int rw,
  88               int blksize, int beg, int nr)
  89 {
  90         ccw->cmd_code = DASD_FBA_CCW_DEFINE_EXTENT;
  91         ccw->flags = 0;
  92         ccw->count = 16;
  93         ccw->cda = (__u32) __pa(data);
  94         memset(data, 0, sizeof (struct DE_fba_data));
  95         if (rw == WRITE)
  96                 (data->mask).perm = 0x0;
  97         else if (rw == READ)
  98                 (data->mask).perm = 0x1;
  99         else
 100                 data->mask.perm = 0x2;
 101         data->blk_size = blksize;
 102         data->ext_loc = beg;
 103         data->ext_end = nr - 1;
 104 }
 105
 106 static void
 107 locate_record(struct ccw1 * ccw, struct LO_fba_data *data, int rw,
 108               int block_nr, int block_ct)
 109 {
 110         ccw->cmd_code = DASD_FBA_CCW_LOCATE;
 111         ccw->flags = 0;
 112         ccw->count = 8;
 113         ccw->cda = (__u32) __pa(data);
 114         memset(data, 0, sizeof (struct LO_fba_data));
 115         if (rw == WRITE)
 116                 data->operation.cmd = 0x5;
 117         else if (rw == READ)
 118                 data->operation.cmd = 0x6;
 119         else
 120                 data->operation.cmd = 0x8;
 121         data->blk_nr = block_nr;
 122         data->blk_ct = block_ct;
 123 }
 124
 125 static int
 126 dasd_fba_check_characteristics(struct dasd_device *device)
 127 {
 128         struct dasd_block *block;
 129         struct dasd_fba_private *private;
 130         struct ccw_device *cdev = device->cdev;
 131         int rc;
 132         int readonly;
 133
 134         private = (struct dasd_fba_private *) device->private;
 135         if (!private) {
 136                 private = kzalloc(sizeof(*private), GFP_KERNEL | GFP_DMA);
 137                 if (!private) {
 138                         dev_warn(&device->cdev->dev,
 139                                  "Allocating memory for private DASD "
 140                                  "data failed\n");
 141                         return -ENOMEM;
 142                 }
 143                 device->private = (void *) private;
 144         } else {
 145                 memset(private, 0, sizeof(*private));
 146         }
 147         block = dasd_alloc_block();
 148         if (IS_ERR(block)) {
 149                 DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s", "could not allocate "
 150                                 "dasd block structure");
 151                 device->private = NULL;
 152                 kfree(private);
 153                 return PTR_ERR(block);
 154         }
 155         device->block = block;
 156         block->base = device;
 157
 158         /* Read Device Characteristics */
 159         rc = dasd_generic_read_dev_chars(device, DASD_FBA_MAGIC,
 160                                          &private->rdc_data, 32);
 161         if (rc) {
 162                 DBF_EVENT_DEVID(DBF_WARNING, cdev, "Read device "
 163                                 "characteristics returned error %d", rc);
 164                 device->block = NULL;
 165                 dasd_free_block(block);
 166                 device->private = NULL;
 167                 kfree(private);
 168                 return rc;
 169         }
 170
 171         device->default_expires = DASD_EXPIRES;
 172         device->default_retries = FBA_DEFAULT_RETRIES;
 173         device->path_data.opm = LPM_ANYPATH;
 174
 175         readonly = dasd_device_is_ro(device);
 176         if (readonly)
 177                 set_bit(DASD_FLAG_DEVICE_RO, &device->flags);
 178
 179         dev_info(&device->cdev->dev,
 180                  "New FBA DASD %04X/%02X (CU %04X/%02X) with %d MB "
 181                  "and %d B/blk%s\n",
 182                  cdev->id.dev_type,
 183                  cdev->id.dev_model,
 184                  cdev->id.cu_type,
 185                  cdev->id.cu_model,
 186                  ((private->rdc_data.blk_bdsa *
 187                    (private->rdc_data.blk_size >> 9)) >> 11),
 188                  private->rdc_data.blk_size,
 189                  readonly ? ", read-only device" : "");
 190         return 0;
 191 }
 192
 193 static int dasd_fba_do_analysis(struct dasd_block *block)
 194 {
 195         struct dasd_fba_private *private;
 196         int sb, rc;
 197
 198         private = (struct dasd_fba_private *) block->base->private;
 199         rc = dasd_check_blocksize(private->rdc_data.blk_size);
 200         if (rc) {
 201                 DBF_DEV_EVENT(DBF_WARNING, block->base, "unknown blocksize %d",
 202                             private->rdc_data.blk_size);
 203                 return rc;
 204         }
 205         block->blocks = private->rdc_data.blk_bdsa;
 206         block->bp_block = private->rdc_data.blk_size;
 207         block->s2b_shift = 0;   /* bits to shift 512 to get a block */
 208         for (sb = 512; sb < private->rdc_data.blk_size; sb = sb << 1)
 209                 block->s2b_shift++;
 210         return 0;
 211 }
 212
 213 static int dasd_fba_fill_geometry(struct dasd_block *block,
 214                                   struct hd_geometry *geo)
 215 {
 216         if (dasd_check_blocksize(block->bp_block) != 0)
 217                 return -EINVAL;
 218         geo->cylinders = (block->blocks << block->s2b_shift) >> 10;
 219         geo->heads = 16;
 220         geo->sectors = 128 >> block->s2b_shift;
 221         return 0;
 222 }
 223
 224 static dasd_erp_fn_t
 225 dasd_fba_erp_action(struct dasd_ccw_req * cqr)
 226 {
 227         return dasd_default_erp_action;
 228 }
 229
 230 static dasd_erp_fn_t
 231 dasd_fba_erp_postaction(struct dasd_ccw_req * cqr)
 232 {
 233         if (cqr->function == dasd_default_erp_action)
 234                 return dasd_default_erp_postaction;
 235
 236         DBF_DEV_EVENT(DBF_WARNING, cqr->startdev, "unknown ERP action %p",
 237                     cqr->function);
 238         return NULL;
 239 }
 240
 241 static void dasd_fba_check_for_device_change(struct dasd_device *device,
 242                                              struct dasd_ccw_req *cqr,
 243                                              struct irb *irb)
 244 {
 245         char mask;
 246
 247         /* first of all check for state change pending interrupt */
 248         mask = DEV_STAT_ATTENTION | DEV_STAT_DEV_END | DEV_STAT_UNIT_EXCEP;
 249         if ((irb->scsw.cmd.dstat & mask) == mask)
 250                 dasd_generic_handle_state_change(device);
 251 };
 252
 253 static struct dasd_ccw_req *dasd_fba_build_cp(struct dasd_device * memdev,
 254                                               struct dasd_block *block,
 255                                               struct request *req)
 256 {
 257         struct dasd_fba_private *private;
 258         unsigned long *idaws;
 259         struct LO_fba_data *LO_data;
 260         struct dasd_ccw_req *cqr;
 261         struct ccw1 *ccw;
 262         struct req_iterator iter;
 263         struct bio_vec bv;
 264         char *dst;
 265         int count, cidaw, cplength, datasize;
 266         sector_t recid, first_rec, last_rec;
 267         unsigned int blksize, off;
 268         unsigned char cmd;
 269
 270         private = (struct dasd_fba_private *) block->base->private;
 271         if (rq_data_dir(req) == READ) {
 272                 cmd = DASD_FBA_CCW_READ;
 273         } else if (rq_data_dir(req) == WRITE) {
 274                 cmd = DASD_FBA_CCW_WRITE;
 275         } else
 276                 return ERR_PTR(-EINVAL);
 277         blksize = block->bp_block;
 278         /* Calculate record id of first and last block. */
 279         first_rec = blk_rq_pos(req) >> block->s2b_shift;
 280         last_rec =
 281                 (blk_rq_pos(req) + blk_rq_sectors(req) - 1) >> block->s2b_shift;
 282         /* Check struct bio and count the number of blocks for the request. */
 283         count = 0;
 284         cidaw = 0;
 285         rq_for_each_segment(bv, req, iter) {
 286                 if (bv.bv_len & (blksize - 1))
 287                         /* Fba can only do full blocks. */
 288                         return ERR_PTR(-EINVAL);
 289                 count += bv.bv_len >> (block->s2b_shift + 9);
 290 #if defined(CONFIG_64BIT)
 291                 if (idal_is_needed (page_address(bv.bv_page), bv.bv_len))
 292                         cidaw += bv.bv_len / blksize;
 293 #endif
 294         }
 295         /* Paranoia. */
 296         if (count != last_rec - first_rec + 1)
 297                 return ERR_PTR(-EINVAL);
 298         /* 1x define extent + 1x locate record + number of blocks */
 299         cplength = 2 + count;
 300         /* 1x define extent + 1x locate record */
 301         datasize = sizeof(struct DE_fba_data) + sizeof(struct LO_fba_data) +
 302                 cidaw * sizeof(unsigned long);
 303         /*
 304          * Find out number of additional locate record ccws if the device
 305          * can't do data chaining.
 306          */
 307         if (private->rdc_data.mode.bits.data_chain == 0) {
 308                 cplength += count - 1;
 309                 datasize += (count - 1)*sizeof(struct LO_fba_data);
 310         }
 311         /* Allocate the ccw request. */
 312         cqr = dasd_smalloc_request(DASD_FBA_MAGIC, cplength, datasize, memdev);
 313         if (IS_ERR(cqr))
 314                 return cqr;
 315         ccw = cqr->cpaddr;
 316         /* First ccw is define extent. */
 317         define_extent(ccw++, cqr->data, rq_data_dir(req),
 318                       block->bp_block, blk_rq_pos(req), blk_rq_sectors(req));
 319         /* Build locate_record + read/write ccws. */
 320         idaws = (unsigned long *) (cqr->data + sizeof(struct DE_fba_data));
 321         LO_data = (struct LO_fba_data *) (idaws + cidaw);
 322         /* Locate record for all blocks for smart devices. */
 323         if (private->rdc_data.mode.bits.data_chain != 0) {
 324                 ccw[-1].flags |= CCW_FLAG_CC;
 325                 locate_record(ccw++, LO_data++, rq_data_dir(req), 0, count);
 326         }
 327         recid = first_rec;
 328         rq_for_each_segment(bv, req, iter) {
 329                 dst = page_address(bv.bv_page) + bv.bv_offset;
 330                 if (dasd_page_cache) {
 331                         char *copy = kmem_cache_alloc(dasd_page_cache,
 332                                                       GFP_DMA | __GFP_NOWARN);
 333                         if (copy && rq_data_dir(req) == WRITE)
 334                                 memcpy(copy + bv.bv_offset, dst, bv.bv_len);
 335                         if (copy)
 336                                 dst = copy + bv.bv_offset;
 337                 }
 338                 for (off = 0; off < bv.bv_len; off += blksize) {
 339                         /* Locate record for stupid devices. */
 340                         if (private->rdc_data.mode.bits.data_chain == 0) {
 341                                 ccw[-1].flags |= CCW_FLAG_CC;
 342                                 locate_record(ccw, LO_data++,
 343                                               rq_data_dir(req),
 344                                               recid - first_rec, 1);
 345                                 ccw->flags = CCW_FLAG_CC;
 346                                 ccw++;
 347                         } else {
 348                                 if (recid > first_rec)
 349                                         ccw[-1].flags |= CCW_FLAG_DC;
 350                                 else
 351                                         ccw[-1].flags |= CCW_FLAG_CC;
 352                         }
 353                         ccw->cmd_code = cmd;
 354                         ccw->count = block->bp_block;
 355                         if (idal_is_needed(dst, blksize)) {
 356                                 ccw->cda = (__u32)(addr_t) idaws;
 357                                 ccw->flags = CCW_FLAG_IDA;
 358                                 idaws = idal_create_words(idaws, dst, blksize);
 359                         } else {
 360                                 ccw->cda = (__u32)(addr_t) dst;
 361                                 ccw->flags = 0;
 362                         }
 363                         ccw++;
 364                         dst += blksize;
 365                         recid++;
 366                 }
 367         }
 368         if (blk_noretry_request(req) ||
 369             block->base->features & DASD_FEATURE_FAILFAST)
 370                 set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags);
 371         cqr->startdev = memdev;
 372         cqr->memdev = memdev;
 373         cqr->block = block;
 374         cqr->expires = memdev->default_expires * HZ;    /* default 5 minutes */
 375         cqr->retries = memdev->default_retries;
 376         cqr->buildclk = get_tod_clock();
 377         cqr->status = DASD_CQR_FILLED;
 378         return cqr;
 379 }
 380
 381 static int
 382 dasd_fba_free_cp(struct dasd_ccw_req *cqr, struct request *req)
 383 {
 384         struct dasd_fba_private *private;
 385         struct ccw1 *ccw;
 386         struct req_iterator iter;
 387         struct bio_vec bv;
 388         char *dst, *cda;
 389         unsigned int blksize, off;
 390         int status;
 391
 392         if (!dasd_page_cache)
 393                 goto out;
 394         private = (struct dasd_fba_private *) cqr->block->base->private;
 395         blksize = cqr->block->bp_block;
 396         ccw = cqr->cpaddr;
 397         /* Skip over define extent & locate record. */
 398         ccw++;
 399         if (private->rdc_data.mode.bits.data_chain != 0)
 400                 ccw++;
 401         rq_for_each_segment(bv, req, iter) {
 402                 dst = page_address(bv.bv_page) + bv.bv_offset;
 403                 for (off = 0; off < bv.bv_len; off += blksize) {
 404                         /* Skip locate record. */
 405                         if (private->rdc_data.mode.bits.data_chain == 0)
 406                                 ccw++;
 407                         if (dst) {
 408                                 if (ccw->flags & CCW_FLAG_IDA)
 409                                         cda = *((char **)((addr_t) ccw->cda));
 410                                 else
 411                                         cda = (char *)((addr_t) ccw->cda);
 412                                 if (dst != cda) {
 413                                         if (rq_data_dir(req) == READ)
 414                                                 memcpy(dst, cda, bv.bv_len);
 415                                         kmem_cache_free(dasd_page_cache,
 416                                             (void *)((addr_t)cda & PAGE_MASK));
 417                                 }
 418                                 dst = NULL;
 419                         }
 420                         ccw++;
 421                 }
 422         }
 423 out:
 424         status = cqr->status == DASD_CQR_DONE;
 425         dasd_sfree_request(cqr, cqr->memdev);
 426         return status;
 427 }
 428
 429 static void dasd_fba_handle_terminated_request(struct dasd_ccw_req *cqr)
 430 {
 431         if (cqr->retries < 0)
 432                 cqr->status = DASD_CQR_FAILED;
 433         else
 434                 cqr->status = DASD_CQR_FILLED;
 435 };
 436
 437 static int
 438 dasd_fba_fill_info(struct dasd_device * device,
 439                    struct dasd_information2_t * info)
 440 {
 441         info->label_block = 1;
 442         info->FBA_layout = 1;
 443         info->format = DASD_FORMAT_LDL;
 444         info->characteristics_size = sizeof(struct dasd_fba_characteristics);
 445         memcpy(info->characteristics,
 446                &((struct dasd_fba_private *) device->private)->rdc_data,
 447                sizeof (struct dasd_fba_characteristics));
 448         info->confdata_size = 0;
 449         return 0;
 450 }
 451
 452 static void
 453 dasd_fba_dump_sense_dbf(struct dasd_device *device, struct irb *irb,
 454                         char *reason)
 455 {
 456         u64 *sense;
 457
 458         sense = (u64 *) dasd_get_sense(irb);
 459         if (sense) {
 460                 DBF_DEV_EVENT(DBF_EMERG, device,
 461                               "%s: %s %02x%02x%02x %016llx %016llx %016llx "
 462                               "%016llx", reason,
 463                               scsw_is_tm(&irb->scsw) ? "t" : "c",
 464                               scsw_cc(&irb->scsw), scsw_cstat(&irb->scsw),
 465                               scsw_dstat(&irb->scsw), sense[0], sense[1],
 466                               sense[2], sense[3]);
 467         } else {
 468                 DBF_DEV_EVENT(DBF_EMERG, device, "%s",
 469                               "SORRY - NO VALID SENSE AVAILABLE\n");
 470         }
 471 }
 472
 473
 474 static void
 475 dasd_fba_dump_sense(struct dasd_device *device, struct dasd_ccw_req * req,
 476                     struct irb *irb)
 477 {
 478         char *page;
 479         struct ccw1 *act, *end, *last;
 480         int len, sl, sct, count;
 481
 482         page = (char *) get_zeroed_page(GFP_ATOMIC);
 483         if (page == NULL) {
 484                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 485                             "No memory to dump sense data");
 486                 return;
 487         }
 488         len = sprintf(page, PRINTK_HEADER
 489                       " I/O status report for device %s:\n",
 490                       dev_name(&device->cdev->dev));
 491         len += sprintf(page + len, PRINTK_HEADER
 492                        " in req: %p CS: 0x%02X DS: 0x%02X\n", req,
 493                        irb->scsw.cmd.cstat, irb->scsw.cmd.dstat);
 494         len += sprintf(page + len, PRINTK_HEADER
 495                        " device %s: Failing CCW: %p\n",
 496                        dev_name(&device->cdev->dev),
 497                        (void *) (addr_t) irb->scsw.cmd.cpa);
 498         if (irb->esw.esw0.erw.cons) {
 499                 for (sl = 0; sl < 4; sl++) {
 500                         len += sprintf(page + len, PRINTK_HEADER
 501                                        " Sense(hex) %2d-%2d:",
 502                                        (8 * sl), ((8 * sl) + 7));
 503
 504                         for (sct = 0; sct < 8; sct++) {
 505                                 len += sprintf(page + len, " %02x",
 506                                                irb->ecw[8 * sl + sct]);
 507                         }
 508                         len += sprintf(page + len, "\n");
 509                 }
 510         } else {
 511                 len += sprintf(page + len, PRINTK_HEADER
 512                                " SORRY - NO VALID SENSE AVAILABLE\n");
 513         }
 514         printk(KERN_ERR "%s", page);
 515
 516         /* dump the Channel Program */
 517         /* print first CCWs (maximum 8) */
 518         act = req->cpaddr;
 519         for (last = act; last->flags & (CCW_FLAG_CC | CCW_FLAG_DC); last++);
 520         end = min(act + 8, last);
 521         len = sprintf(page, PRINTK_HEADER " Related CP in req: %p\n", req);
 522         while (act <= end) {
 523                 len += sprintf(page + len, PRINTK_HEADER
 524                                " CCW %p: %08X %08X DAT:",
 525                                act, ((int *) act)[0], ((int *) act)[1]);
 526                 for (count = 0; count < 32 && count < act->count;
 527                      count += sizeof(int))
 528                         len += sprintf(page + len, " %08X",
 529                                        ((int *) (addr_t) act->cda)
 530                                        [(count>>2)]);
 531                 len += sprintf(page + len, "\n");
 532                 act++;
 533         }
 534         printk(KERN_ERR "%s", page);
 535
 536
 537         /* print failing CCW area */
 538         len = 0;
 539         if (act <  ((struct ccw1 *)(addr_t) irb->scsw.cmd.cpa) - 2) {
 540                 act = ((struct ccw1 *)(addr_t) irb->scsw.cmd.cpa) - 2;
 541                 len += sprintf(page + len, PRINTK_HEADER "......\n");
 542         }
 543         end = min((struct ccw1 *)(addr_t) irb->scsw.cmd.cpa + 2, last);
 544         while (act <= end) {
 545                 len += sprintf(page + len, PRINTK_HEADER
 546                                " CCW %p: %08X %08X DAT:",
 547                                act, ((int *) act)[0], ((int *) act)[1]);
 548                 for (count = 0; count < 32 && count < act->count;
 549                      count += sizeof(int))
 550                         len += sprintf(page + len, " %08X",
 551                                        ((int *) (addr_t) act->cda)
 552                                        [(count>>2)]);
 553                 len += sprintf(page + len, "\n");
 554                 act++;
 555         }
 556
 557         /* print last CCWs */
 558         if (act <  last - 2) {
 559                 act = last - 2;
 560                 len += sprintf(page + len, PRINTK_HEADER "......\n");
 561         }
 562         while (act <= last) {
 563                 len += sprintf(page + len, PRINTK_HEADER
 564                                " CCW %p: %08X %08X DAT:",
 565                                act, ((int *) act)[0], ((int *) act)[1]);
 566                 for (count = 0; count < 32 && count < act->count;
 567                      count += sizeof(int))
 568                         len += sprintf(page + len, " %08X",
 569                                        ((int *) (addr_t) act->cda)
 570                                        [(count>>2)]);
 571                 len += sprintf(page + len, "\n");
 572                 act++;
 573         }
 574         if (len > 0)
 575                 printk(KERN_ERR "%s", page);
 576         free_page((unsigned long) page);
 577 }
 578
 579 /*
 580  * max_blocks is dependent on the amount of storage that is available
 581  * in the static io buffer for each device. Currently each device has
 582  * 8192 bytes (=2 pages). For 64 bit one dasd_mchunkt_t structure has
 583  * 24 bytes, the struct dasd_ccw_req has 136 bytes and each block can use
 584  * up to 16 bytes (8 for the ccw and 8 for the idal pointer). In
 585  * addition we have one define extent ccw + 16 bytes of data and a
 586  * locate record ccw for each block (stupid devices!) + 16 bytes of data.
 587  * That makes:
 588  * (8192 - 24 - 136 - 8 - 16) / 40 = 200.2 blocks at maximum.
 589  * We want to fit two into the available memory so that we can immediately
 590  * start the next request if one finishes off. That makes 100.1 blocks
 591  * for one request. Give a little safety and the result is 96.
 592  */
 593 static struct dasd_discipline dasd_fba_discipline = {
 594         .owner = THIS_MODULE,
 595         .name = "FBA ",
 596         .ebcname = "FBA ",
 597         .max_blocks = 96,
 598         .check_device = dasd_fba_check_characteristics,
 599         .do_analysis = dasd_fba_do_analysis,
 600         .verify_path = dasd_generic_verify_path,
 601         .fill_geometry = dasd_fba_fill_geometry,
 602         .start_IO = dasd_start_IO,
 603         .term_IO = dasd_term_IO,
 604         .handle_terminated_request = dasd_fba_handle_terminated_request,
 605         .erp_action = dasd_fba_erp_action,
 606         .erp_postaction = dasd_fba_erp_postaction,
 607         .check_for_device_change = dasd_fba_check_for_device_change,
 608         .build_cp = dasd_fba_build_cp,
 609         .free_cp = dasd_fba_free_cp,
 610         .dump_sense = dasd_fba_dump_sense,
 611         .dump_sense_dbf = dasd_fba_dump_sense_dbf,
 612         .fill_info = dasd_fba_fill_info,
 613 };
 614
 615 static int __init
 616 dasd_fba_init(void)
 617 {
 618         int ret;
 619
 620         ASCEBC(dasd_fba_discipline.ebcname, 4);
 621         ret = ccw_driver_register(&dasd_fba_driver);
 622         if (!ret)
 623                 wait_for_device_probe();
 624
 625         return ret;
 626 }
 627
 628 static void __exit
 629 dasd_fba_cleanup(void)
 630 {
 631         ccw_driver_unregister(&dasd_fba_driver);
 632 }
 633
 634 module_init(dasd_fba_init);
 635 module_exit(dasd_fba_cleanup);