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[S390] dasd: tunable missing interrupt handler
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1 /*
2  * File...........: linux/drivers/s390/block/dasd_diag.c
3  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
4  * Based on.......: linux/drivers/s390/block/mdisk.c
5  * ...............: by Hartmunt Penner <hpenner@de.ibm.com>
6  * Bugreports.to..: <Linux390@de.ibm.com>
7  * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999,2000
8  *
9  */
10
11 #define KMSG_COMPONENT "dasd"
12
13 #include <linux/stddef.h>
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
16 #include <linux/hdreg.h>
17 #include <linux/bio.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/jiffies.h>
21
22 #include <asm/dasd.h>
23 #include <asm/debug.h>
24 #include <asm/ebcdic.h>
25 #include <asm/io.h>
26 #include <asm/s390_ext.h>
27 #include <asm/vtoc.h>
28 #include <asm/diag.h>
29
30 #include "dasd_int.h"
31 #include "dasd_diag.h"
32
33 #define PRINTK_HEADER "dasd(diag):"
34
35 MODULE_LICENSE("GPL");
36
37 /* The maximum number of blocks per request (max_blocks) is dependent on the
38  * amount of storage that is available in the static I/O buffer for each
39  * device. Currently each device gets 2 pages. We want to fit two requests
40  * into the available memory so that we can immediately start the next if one
41  * finishes. */
42 #define DIAG_MAX_BLOCKS (((2 * PAGE_SIZE - sizeof(struct dasd_ccw_req) - \
43                            sizeof(struct dasd_diag_req)) / \
44                            sizeof(struct dasd_diag_bio)) / 2)
45 #define DIAG_MAX_RETRIES        32
46 #define DIAG_TIMEOUT            50
47
48 static struct dasd_discipline dasd_diag_discipline;
49
50 struct dasd_diag_private {
51         struct dasd_diag_characteristics rdc_data;
52         struct dasd_diag_rw_io iob;
53         struct dasd_diag_init_io iib;
54         blocknum_t pt_block;
55         struct ccw_dev_id dev_id;
56 };
57
58 struct dasd_diag_req {
59         unsigned int block_count;
60         struct dasd_diag_bio bio[0];
61 };
62
63 static const u8 DASD_DIAG_CMS1[] = { 0xc3, 0xd4, 0xe2, 0xf1 };/* EBCDIC CMS1 */
64
65 /* Perform DIAG250 call with block I/O parameter list iob (input and output)
66  * and function code cmd.
67  * In case of an exception return 3. Otherwise return result of bitwise OR of
68  * resulting condition code and DIAG return code. */
69 static inline int dia250(void *iob, int cmd)
70 {
71         register unsigned long reg2 asm ("2") = (unsigned long) iob;
72         typedef union {
73                 struct dasd_diag_init_io init_io;
74                 struct dasd_diag_rw_io rw_io;
75         } addr_type;
76         int rc;
77
78         rc = 3;
79         asm volatile(
80                 "       diag    2,%2,0x250\n"
81                 "0:     ipm     %0\n"
82                 "       srl     %0,28\n"
83                 "       or      %0,3\n"
84                 "1:\n"
85                 EX_TABLE(0b,1b)
86                 : "+d" (rc), "=m" (*(addr_type *) iob)
87                 : "d" (cmd), "d" (reg2), "m" (*(addr_type *) iob)
88                 : "3", "cc");
89         return rc;
90 }
91
92 /* Initialize block I/O to DIAG device using the specified blocksize and
93  * block offset. On success, return zero and set end_block to contain the
94  * number of blocks on the device minus the specified offset. Return non-zero
95  * otherwise. */
96 static inline int
97 mdsk_init_io(struct dasd_device *device, unsigned int blocksize,
98              blocknum_t offset, blocknum_t *end_block)
99 {
100         struct dasd_diag_private *private;
101         struct dasd_diag_init_io *iib;
102         int rc;
103
104         private = (struct dasd_diag_private *) device->private;
105         iib = &private->iib;
106         memset(iib, 0, sizeof (struct dasd_diag_init_io));
107
108         iib->dev_nr = private->dev_id.devno;
109         iib->block_size = blocksize;
110         iib->offset = offset;
111         iib->flaga = DASD_DIAG_FLAGA_DEFAULT;
112
113         rc = dia250(iib, INIT_BIO);
114
115         if ((rc & 3) == 0 && end_block)
116                 *end_block = iib->end_block;
117
118         return rc;
119 }
120
121 /* Remove block I/O environment for device. Return zero on success, non-zero
122  * otherwise. */
123 static inline int
124 mdsk_term_io(struct dasd_device * device)
125 {
126         struct dasd_diag_private *private;
127         struct dasd_diag_init_io *iib;
128         int rc;
129
130         private = (struct dasd_diag_private *) device->private;
131         iib = &private->iib;
132         memset(iib, 0, sizeof (struct dasd_diag_init_io));
133         iib->dev_nr = private->dev_id.devno;
134         rc = dia250(iib, TERM_BIO);
135         return rc;
136 }
137
138 /* Error recovery for failed DIAG requests - try to reestablish the DIAG
139  * environment. */
140 static void
141 dasd_diag_erp(struct dasd_device *device)
142 {
143         int rc;
144
145         mdsk_term_io(device);
146         rc = mdsk_init_io(device, device->block->bp_block, 0, NULL);
147         if (rc == 4) {
148                 if (!(test_and_set_bit(DASD_FLAG_DEVICE_RO, &device->flags)))
149                         pr_warning("%s: The access mode of a DIAG device "
150                                    "changed to read-only\n",
151                                    dev_name(&device->cdev->dev));
152                 rc = 0;
153         }
154         if (rc)
155                 pr_warning("%s: DIAG ERP failed with "
156                             "rc=%d\n", dev_name(&device->cdev->dev), rc);
157 }
158
159 /* Start a given request at the device. Return zero on success, non-zero
160  * otherwise. */
161 static int
162 dasd_start_diag(struct dasd_ccw_req * cqr)
163 {
164         struct dasd_device *device;
165         struct dasd_diag_private *private;
166         struct dasd_diag_req *dreq;
167         int rc;
168
169         device = cqr->startdev;
170         if (cqr->retries < 0) {
171                 DBF_DEV_EVENT(DBF_ERR, device, "DIAG start_IO: request %p "
172                             "- no retry left)", cqr);
173                 cqr->status = DASD_CQR_ERROR;
174                 return -EIO;
175         }
176         private = (struct dasd_diag_private *) device->private;
177         dreq = (struct dasd_diag_req *) cqr->data;
178
179         private->iob.dev_nr = private->dev_id.devno;
180         private->iob.key = 0;
181         private->iob.flags = DASD_DIAG_RWFLAG_ASYNC;
182         private->iob.block_count = dreq->block_count;
183         private->iob.interrupt_params = (addr_t) cqr;
184         private->iob.bio_list = dreq->bio;
185         private->iob.flaga = DASD_DIAG_FLAGA_DEFAULT;
186
187         cqr->startclk = get_clock();
188         cqr->starttime = jiffies;
189         cqr->retries--;
190
191         rc = dia250(&private->iob, RW_BIO);
192         switch (rc) {
193         case 0: /* Synchronous I/O finished successfully */
194                 cqr->stopclk = get_clock();
195                 cqr->status = DASD_CQR_SUCCESS;
196                 /* Indicate to calling function that only a dasd_schedule_bh()
197                    and no timer is needed */
198                 rc = -EACCES;
199                 break;
200         case 8: /* Asynchronous I/O was started */
201                 cqr->status = DASD_CQR_IN_IO;
202                 rc = 0;
203                 break;
204         default: /* Error condition */
205                 cqr->status = DASD_CQR_QUEUED;
206                 DBF_DEV_EVENT(DBF_WARNING, device, "dia250 returned rc=%d", rc);
207                 dasd_diag_erp(device);
208                 rc = -EIO;
209                 break;
210         }
211         cqr->intrc = rc;
212         return rc;
213 }
214
215 /* Terminate given request at the device. */
216 static int
217 dasd_diag_term_IO(struct dasd_ccw_req * cqr)
218 {
219         struct dasd_device *device;
220
221         device = cqr->startdev;
222         mdsk_term_io(device);
223         mdsk_init_io(device, device->block->bp_block, 0, NULL);
224         cqr->status = DASD_CQR_CLEAR_PENDING;
225         cqr->stopclk = get_clock();
226         dasd_schedule_device_bh(device);
227         return 0;
228 }
229
230 /* Handle external interruption. */
231 static void
232 dasd_ext_handler(__u16 code)
233 {
234         struct dasd_ccw_req *cqr, *next;
235         struct dasd_device *device;
236         unsigned long long expires;
237         unsigned long flags;
238         u8 int_code, status;
239         addr_t ip;
240         int rc;
241
242         int_code = *((u8 *) DASD_DIAG_LC_INT_CODE);
243         status = *((u8 *) DASD_DIAG_LC_INT_STATUS);
244         switch (int_code) {
245         case DASD_DIAG_CODE_31BIT:
246                 ip = (addr_t) *((u32 *) DASD_DIAG_LC_INT_PARM_31BIT);
247                 break;
248         case DASD_DIAG_CODE_64BIT:
249                 ip = (addr_t) *((u64 *) DASD_DIAG_LC_INT_PARM_64BIT);
250                 break;
251         default:
252                 return;
253         }
254         if (!ip) {              /* no intparm: unsolicited interrupt */
255                 DBF_EVENT(DBF_NOTICE, "%s", "caught unsolicited "
256                               "interrupt");
257                 return;
258         }
259         cqr = (struct dasd_ccw_req *) ip;
260         device = (struct dasd_device *) cqr->startdev;
261         if (strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
262                 DBF_DEV_EVENT(DBF_WARNING, device,
263                             " magic number of dasd_ccw_req 0x%08X doesn't"
264                             " match discipline 0x%08X",
265                             cqr->magic, *(int *) (&device->discipline->name));
266                 return;
267         }
268
269         /* get irq lock to modify request queue */
270         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
271
272         /* Check for a pending clear operation */
273         if (cqr->status == DASD_CQR_CLEAR_PENDING) {
274                 cqr->status = DASD_CQR_CLEARED;
275                 dasd_device_clear_timer(device);
276                 dasd_schedule_device_bh(device);
277                 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
278                 return;
279         }
280
281         cqr->stopclk = get_clock();
282
283         expires = 0;
284         if (status == 0) {
285                 cqr->status = DASD_CQR_SUCCESS;
286                 /* Start first request on queue if possible -> fast_io. */
287                 if (!list_empty(&device->ccw_queue)) {
288                         next = list_entry(device->ccw_queue.next,
289                                           struct dasd_ccw_req, devlist);
290                         if (next->status == DASD_CQR_QUEUED) {
291                                 rc = dasd_start_diag(next);
292                                 if (rc == 0)
293                                         expires = next->expires;
294                         }
295                 }
296         } else {
297                 cqr->status = DASD_CQR_QUEUED;
298                 DBF_DEV_EVENT(DBF_DEBUG, device, "interrupt status for "
299                             "request %p was %d (%d retries left)", cqr, status,
300                             cqr->retries);
301                 dasd_diag_erp(device);
302         }
303
304         if (expires != 0)
305                 dasd_device_set_timer(device, expires);
306         else
307                 dasd_device_clear_timer(device);
308         dasd_schedule_device_bh(device);
309
310         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
311 }
312
313 /* Check whether device can be controlled by DIAG discipline. Return zero on
314  * success, non-zero otherwise. */
315 static int
316 dasd_diag_check_device(struct dasd_device *device)
317 {
318         struct dasd_block *block;
319         struct dasd_diag_private *private;
320         struct dasd_diag_characteristics *rdc_data;
321         struct dasd_diag_bio bio;
322         struct vtoc_cms_label *label;
323         blocknum_t end_block;
324         unsigned int sb, bsize;
325         int rc;
326
327         private = (struct dasd_diag_private *) device->private;
328         if (private == NULL) {
329                 private = kzalloc(sizeof(struct dasd_diag_private),GFP_KERNEL);
330                 if (private == NULL) {
331                         DBF_DEV_EVENT(DBF_WARNING, device, "%s",
332                                 "Allocating memory for private DASD data "
333                                       "failed\n");
334                         return -ENOMEM;
335                 }
336                 ccw_device_get_id(device->cdev, &private->dev_id);
337                 device->private = (void *) private;
338         }
339         block = dasd_alloc_block();
340         if (IS_ERR(block)) {
341                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
342                             "could not allocate dasd block structure");
343                 device->private = NULL;
344                 kfree(private);
345                 return PTR_ERR(block);
346         }
347         device->block = block;
348         block->base = device;
349
350         /* Read Device Characteristics */
351         rdc_data = (void *) &(private->rdc_data);
352         rdc_data->dev_nr = private->dev_id.devno;
353         rdc_data->rdc_len = sizeof (struct dasd_diag_characteristics);
354
355         rc = diag210((struct diag210 *) rdc_data);
356         if (rc) {
357                 DBF_DEV_EVENT(DBF_WARNING, device, "failed to retrieve device "
358                             "information (rc=%d)", rc);
359                 rc = -EOPNOTSUPP;
360                 goto out;
361         }
362
363         device->default_expires = DIAG_TIMEOUT;
364
365         /* Figure out position of label block */
366         switch (private->rdc_data.vdev_class) {
367         case DEV_CLASS_FBA:
368                 private->pt_block = 1;
369                 break;
370         case DEV_CLASS_ECKD:
371                 private->pt_block = 2;
372                 break;
373         default:
374                 pr_warning("%s: Device type %d is not supported "
375                            "in DIAG mode\n", dev_name(&device->cdev->dev),
376                            private->rdc_data.vdev_class);
377                 rc = -EOPNOTSUPP;
378                 goto out;
379         }
380
381         DBF_DEV_EVENT(DBF_INFO, device,
382                       "%04X: %04X on real %04X/%02X",
383                       rdc_data->dev_nr,
384                       rdc_data->vdev_type,
385                       rdc_data->rdev_type, rdc_data->rdev_model);
386
387         /* terminate all outstanding operations */
388         mdsk_term_io(device);
389
390         /* figure out blocksize of device */
391         label = (struct vtoc_cms_label *) get_zeroed_page(GFP_KERNEL);
392         if (label == NULL)  {
393                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
394                             "No memory to allocate initialization request");
395                 rc = -ENOMEM;
396                 goto out;
397         }
398         rc = 0;
399         end_block = 0;
400         /* try all sizes - needed for ECKD devices */
401         for (bsize = 512; bsize <= PAGE_SIZE; bsize <<= 1) {
402                 mdsk_init_io(device, bsize, 0, &end_block);
403                 memset(&bio, 0, sizeof (struct dasd_diag_bio));
404                 bio.type = MDSK_READ_REQ;
405                 bio.block_number = private->pt_block + 1;
406                 bio.buffer = label;
407                 memset(&private->iob, 0, sizeof (struct dasd_diag_rw_io));
408                 private->iob.dev_nr = rdc_data->dev_nr;
409                 private->iob.key = 0;
410                 private->iob.flags = 0; /* do synchronous io */
411                 private->iob.block_count = 1;
412                 private->iob.interrupt_params = 0;
413                 private->iob.bio_list = &bio;
414                 private->iob.flaga = DASD_DIAG_FLAGA_DEFAULT;
415                 rc = dia250(&private->iob, RW_BIO);
416                 if (rc == 3) {
417                         pr_warning("%s: A 64-bit DIAG call failed\n",
418                                    dev_name(&device->cdev->dev));
419                         rc = -EOPNOTSUPP;
420                         goto out_label;
421                 }
422                 mdsk_term_io(device);
423                 if (rc == 0)
424                         break;
425         }
426         if (bsize > PAGE_SIZE) {
427                 pr_warning("%s: Accessing the DASD failed because of an "
428                            "incorrect format (rc=%d)\n",
429                            dev_name(&device->cdev->dev), rc);
430                 rc = -EIO;
431                 goto out_label;
432         }
433         /* check for label block */
434         if (memcmp(label->label_id, DASD_DIAG_CMS1,
435                   sizeof(DASD_DIAG_CMS1)) == 0) {
436                 /* get formatted blocksize from label block */
437                 bsize = (unsigned int) label->block_size;
438                 block->blocks = (unsigned long) label->block_count;
439         } else
440                 block->blocks = end_block;
441         block->bp_block = bsize;
442         block->s2b_shift = 0;   /* bits to shift 512 to get a block */
443         for (sb = 512; sb < bsize; sb = sb << 1)
444                 block->s2b_shift++;
445         rc = mdsk_init_io(device, block->bp_block, 0, NULL);
446         if (rc && (rc != 4)) {
447                 pr_warning("%s: DIAG initialization failed with rc=%d\n",
448                            dev_name(&device->cdev->dev), rc);
449                 rc = -EIO;
450         } else {
451                 if (rc == 4)
452                         set_bit(DASD_FLAG_DEVICE_RO, &device->flags);
453                 pr_info("%s: New DASD with %ld byte/block, total size %ld "
454                         "KB%s\n", dev_name(&device->cdev->dev),
455                         (unsigned long) block->bp_block,
456                         (unsigned long) (block->blocks <<
457                                          block->s2b_shift) >> 1,
458                         (rc == 4) ? ", read-only device" : "");
459                 rc = 0;
460         }
461 out_label:
462         free_page((long) label);
463 out:
464         if (rc) {
465                 device->block = NULL;
466                 dasd_free_block(block);
467                 device->private = NULL;
468                 kfree(private);
469         }
470         return rc;
471 }
472
473 /* Fill in virtual disk geometry for device. Return zero on success, non-zero
474  * otherwise. */
475 static int
476 dasd_diag_fill_geometry(struct dasd_block *block, struct hd_geometry *geo)
477 {
478         if (dasd_check_blocksize(block->bp_block) != 0)
479                 return -EINVAL;
480         geo->cylinders = (block->blocks << block->s2b_shift) >> 10;
481         geo->heads = 16;
482         geo->sectors = 128 >> block->s2b_shift;
483         return 0;
484 }
485
486 static dasd_erp_fn_t
487 dasd_diag_erp_action(struct dasd_ccw_req * cqr)
488 {
489         return dasd_default_erp_action;
490 }
491
492 static dasd_erp_fn_t
493 dasd_diag_erp_postaction(struct dasd_ccw_req * cqr)
494 {
495         return dasd_default_erp_postaction;
496 }
497
498 /* Create DASD request from block device request. Return pointer to new
499  * request on success, ERR_PTR otherwise. */
500 static struct dasd_ccw_req *dasd_diag_build_cp(struct dasd_device *memdev,
501                                                struct dasd_block *block,
502                                                struct request *req)
503 {
504         struct dasd_ccw_req *cqr;
505         struct dasd_diag_req *dreq;
506         struct dasd_diag_bio *dbio;
507         struct req_iterator iter;
508         struct bio_vec *bv;
509         char *dst;
510         unsigned int count, datasize;
511         sector_t recid, first_rec, last_rec;
512         unsigned int blksize, off;
513         unsigned char rw_cmd;
514
515         if (rq_data_dir(req) == READ)
516                 rw_cmd = MDSK_READ_REQ;
517         else if (rq_data_dir(req) == WRITE)
518                 rw_cmd = MDSK_WRITE_REQ;
519         else
520                 return ERR_PTR(-EINVAL);
521         blksize = block->bp_block;
522         /* Calculate record id of first and last block. */
523         first_rec = blk_rq_pos(req) >> block->s2b_shift;
524         last_rec =
525                 (blk_rq_pos(req) + blk_rq_sectors(req) - 1) >> block->s2b_shift;
526         /* Check struct bio and count the number of blocks for the request. */
527         count = 0;
528         rq_for_each_segment(bv, req, iter) {
529                 if (bv->bv_len & (blksize - 1))
530                         /* Fba can only do full blocks. */
531                         return ERR_PTR(-EINVAL);
532                 count += bv->bv_len >> (block->s2b_shift + 9);
533         }
534         /* Paranoia. */
535         if (count != last_rec - first_rec + 1)
536                 return ERR_PTR(-EINVAL);
537         /* Build the request */
538         datasize = sizeof(struct dasd_diag_req) +
539                 count*sizeof(struct dasd_diag_bio);
540         cqr = dasd_smalloc_request(DASD_DIAG_MAGIC, 0, datasize, memdev);
541         if (IS_ERR(cqr))
542                 return cqr;
543
544         dreq = (struct dasd_diag_req *) cqr->data;
545         dreq->block_count = count;
546         dbio = dreq->bio;
547         recid = first_rec;
548         rq_for_each_segment(bv, req, iter) {
549                 dst = page_address(bv->bv_page) + bv->bv_offset;
550                 for (off = 0; off < bv->bv_len; off += blksize) {
551                         memset(dbio, 0, sizeof (struct dasd_diag_bio));
552                         dbio->type = rw_cmd;
553                         dbio->block_number = recid + 1;
554                         dbio->buffer = dst;
555                         dbio++;
556                         dst += blksize;
557                         recid++;
558                 }
559         }
560         cqr->retries = DIAG_MAX_RETRIES;
561         cqr->buildclk = get_clock();
562         if (blk_noretry_request(req) ||
563             block->base->features & DASD_FEATURE_FAILFAST)
564                 set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags);
565         cqr->startdev = memdev;
566         cqr->memdev = memdev;
567         cqr->block = block;
568         cqr->expires = memdev->default_expires * HZ;
569         cqr->status = DASD_CQR_FILLED;
570         return cqr;
571 }
572
573 /* Release DASD request. Return non-zero if request was successful, zero
574  * otherwise. */
575 static int
576 dasd_diag_free_cp(struct dasd_ccw_req *cqr, struct request *req)
577 {
578         int status;
579
580         status = cqr->status == DASD_CQR_DONE;
581         dasd_sfree_request(cqr, cqr->memdev);
582         return status;
583 }
584
585 static void dasd_diag_handle_terminated_request(struct dasd_ccw_req *cqr)
586 {
587         cqr->status = DASD_CQR_FILLED;
588 };
589
590 /* Fill in IOCTL data for device. */
591 static int
592 dasd_diag_fill_info(struct dasd_device * device,
593                     struct dasd_information2_t * info)
594 {
595         struct dasd_diag_private *private;
596
597         private = (struct dasd_diag_private *) device->private;
598         info->label_block = (unsigned int) private->pt_block;
599         info->FBA_layout = 1;
600         info->format = DASD_FORMAT_LDL;
601         info->characteristics_size = sizeof (struct dasd_diag_characteristics);
602         memcpy(info->characteristics,
603                &((struct dasd_diag_private *) device->private)->rdc_data,
604                sizeof (struct dasd_diag_characteristics));
605         info->confdata_size = 0;
606         return 0;
607 }
608
609 static void
610 dasd_diag_dump_sense(struct dasd_device *device, struct dasd_ccw_req * req,
611                      struct irb *stat)
612 {
613         DBF_DEV_EVENT(DBF_WARNING, device, "%s",
614                     "dump sense not available for DIAG data");
615 }
616
617 static struct dasd_discipline dasd_diag_discipline = {
618         .owner = THIS_MODULE,
619         .name = "DIAG",
620         .ebcname = "DIAG",
621         .max_blocks = DIAG_MAX_BLOCKS,
622         .check_device = dasd_diag_check_device,
623         .fill_geometry = dasd_diag_fill_geometry,
624         .start_IO = dasd_start_diag,
625         .term_IO = dasd_diag_term_IO,
626         .handle_terminated_request = dasd_diag_handle_terminated_request,
627         .erp_action = dasd_diag_erp_action,
628         .erp_postaction = dasd_diag_erp_postaction,
629         .build_cp = dasd_diag_build_cp,
630         .free_cp = dasd_diag_free_cp,
631         .dump_sense = dasd_diag_dump_sense,
632         .fill_info = dasd_diag_fill_info,
633 };
634
635 static int __init
636 dasd_diag_init(void)
637 {
638         if (!MACHINE_IS_VM) {
639                 pr_info("Discipline %s cannot be used without z/VM\n",
640                         dasd_diag_discipline.name);
641                 return -ENODEV;
642         }
643         ASCEBC(dasd_diag_discipline.ebcname, 4);
644
645         ctl_set_bit(0, 9);
646         register_external_interrupt(0x2603, dasd_ext_handler);
647         dasd_diag_discipline_pointer = &dasd_diag_discipline;
648         return 0;
649 }
650
651 static void __exit
652 dasd_diag_cleanup(void)
653 {
654         unregister_external_interrupt(0x2603, dasd_ext_handler);
655         ctl_clear_bit(0, 9);
656         dasd_diag_discipline_pointer = NULL;
657 }
658
659 module_init(dasd_diag_init);
660 module_exit(dasd_diag_cleanup);