xref: /openbmc/linux/drivers/s390/block/dasd_diag.c (revision b830f94f)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
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  * Copyright IBM Corp. 1999, 2000
8  *
9  */
10 
11 #define KMSG_COMPONENT "dasd"
12 
13 #include <linux/kernel_stat.h>
14 #include <linux/stddef.h>
15 #include <linux/kernel.h>
16 #include <linux/slab.h>
17 #include <linux/hdreg.h>
18 #include <linux/bio.h>
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <linux/jiffies.h>
22 
23 #include <asm/dasd.h>
24 #include <asm/debug.h>
25 #include <asm/diag.h>
26 #include <asm/ebcdic.h>
27 #include <asm/io.h>
28 #include <asm/irq.h>
29 #include <asm/vtoc.h>
30 
31 #include "dasd_int.h"
32 #include "dasd_diag.h"
33 
34 #define PRINTK_HEADER "dasd(diag):"
35 
36 MODULE_LICENSE("GPL");
37 
38 /* The maximum number of blocks per request (max_blocks) is dependent on the
39  * amount of storage that is available in the static I/O buffer for each
40  * device. Currently each device gets 2 pages. We want to fit two requests
41  * into the available memory so that we can immediately start the next if one
42  * finishes. */
43 #define DIAG_MAX_BLOCKS	(((2 * PAGE_SIZE - sizeof(struct dasd_ccw_req) - \
44 			   sizeof(struct dasd_diag_req)) / \
45 		           sizeof(struct dasd_diag_bio)) / 2)
46 #define DIAG_MAX_RETRIES	32
47 #define DIAG_TIMEOUT		50
48 
49 static struct dasd_discipline dasd_diag_discipline;
50 
51 struct dasd_diag_private {
52 	struct dasd_diag_characteristics rdc_data;
53 	struct dasd_diag_rw_io iob;
54 	struct dasd_diag_init_io iib;
55 	blocknum_t pt_block;
56 	struct ccw_dev_id dev_id;
57 };
58 
59 struct dasd_diag_req {
60 	unsigned int block_count;
61 	struct dasd_diag_bio bio[0];
62 };
63 
64 static const u8 DASD_DIAG_CMS1[] = { 0xc3, 0xd4, 0xe2, 0xf1 };/* EBCDIC CMS1 */
65 
66 /* Perform DIAG250 call with block I/O parameter list iob (input and output)
67  * and function code cmd.
68  * In case of an exception return 3. Otherwise return result of bitwise OR of
69  * resulting condition code and DIAG return code. */
70 static inline int __dia250(void *iob, int cmd)
71 {
72 	register unsigned long reg2 asm ("2") = (unsigned long) iob;
73 	typedef union {
74 		struct dasd_diag_init_io init_io;
75 		struct dasd_diag_rw_io rw_io;
76 	} addr_type;
77 	int rc;
78 
79 	rc = 3;
80 	asm volatile(
81 		"	diag	2,%2,0x250\n"
82 		"0:	ipm	%0\n"
83 		"	srl	%0,28\n"
84 		"	or	%0,3\n"
85 		"1:\n"
86 		EX_TABLE(0b,1b)
87 		: "+d" (rc), "=m" (*(addr_type *) iob)
88 		: "d" (cmd), "d" (reg2), "m" (*(addr_type *) iob)
89 		: "3", "cc");
90 	return rc;
91 }
92 
93 static inline int dia250(void *iob, int cmd)
94 {
95 	diag_stat_inc(DIAG_STAT_X250);
96 	return __dia250(iob, cmd);
97 }
98 
99 /* Initialize block I/O to DIAG device using the specified blocksize and
100  * block offset. On success, return zero and set end_block to contain the
101  * number of blocks on the device minus the specified offset. Return non-zero
102  * otherwise. */
103 static inline int
104 mdsk_init_io(struct dasd_device *device, unsigned int blocksize,
105 	     blocknum_t offset, blocknum_t *end_block)
106 {
107 	struct dasd_diag_private *private = device->private;
108 	struct dasd_diag_init_io *iib = &private->iib;
109 	int rc;
110 
111 	memset(iib, 0, sizeof (struct dasd_diag_init_io));
112 
113 	iib->dev_nr = private->dev_id.devno;
114 	iib->block_size = blocksize;
115 	iib->offset = offset;
116 	iib->flaga = DASD_DIAG_FLAGA_DEFAULT;
117 
118 	rc = dia250(iib, INIT_BIO);
119 
120 	if ((rc & 3) == 0 && end_block)
121 		*end_block = iib->end_block;
122 
123 	return rc;
124 }
125 
126 /* Remove block I/O environment for device. Return zero on success, non-zero
127  * otherwise. */
128 static inline int
129 mdsk_term_io(struct dasd_device * device)
130 {
131 	struct dasd_diag_private *private = device->private;
132 	struct dasd_diag_init_io *iib = &private->iib;
133 	int rc;
134 
135 	memset(iib, 0, sizeof (struct dasd_diag_init_io));
136 	iib->dev_nr = private->dev_id.devno;
137 	rc = dia250(iib, TERM_BIO);
138 	return rc;
139 }
140 
141 /* Error recovery for failed DIAG requests - try to reestablish the DIAG
142  * environment. */
143 static void
144 dasd_diag_erp(struct dasd_device *device)
145 {
146 	int rc;
147 
148 	mdsk_term_io(device);
149 	rc = mdsk_init_io(device, device->block->bp_block, 0, NULL);
150 	if (rc == 4) {
151 		if (!(test_and_set_bit(DASD_FLAG_DEVICE_RO, &device->flags)))
152 			pr_warn("%s: The access mode of a DIAG device changed to read-only\n",
153 				dev_name(&device->cdev->dev));
154 		rc = 0;
155 	}
156 	if (rc)
157 		pr_warn("%s: DIAG ERP failed with rc=%d\n",
158 			dev_name(&device->cdev->dev), rc);
159 }
160 
161 /* Start a given request at the device. Return zero on success, non-zero
162  * otherwise. */
163 static int
164 dasd_start_diag(struct dasd_ccw_req * cqr)
165 {
166 	struct dasd_device *device;
167 	struct dasd_diag_private *private;
168 	struct dasd_diag_req *dreq;
169 	int rc;
170 
171 	device = cqr->startdev;
172 	if (cqr->retries < 0) {
173 		DBF_DEV_EVENT(DBF_ERR, device, "DIAG start_IO: request %p "
174 			    "- no retry left)", cqr);
175 		cqr->status = DASD_CQR_ERROR;
176 		return -EIO;
177 	}
178 	private = device->private;
179 	dreq = cqr->data;
180 
181 	private->iob.dev_nr = private->dev_id.devno;
182 	private->iob.key = 0;
183 	private->iob.flags = DASD_DIAG_RWFLAG_ASYNC;
184 	private->iob.block_count = dreq->block_count;
185 	private->iob.interrupt_params = (addr_t) cqr;
186 	private->iob.bio_list = dreq->bio;
187 	private->iob.flaga = DASD_DIAG_FLAGA_DEFAULT;
188 
189 	cqr->startclk = get_tod_clock();
190 	cqr->starttime = jiffies;
191 	cqr->retries--;
192 
193 	rc = dia250(&private->iob, RW_BIO);
194 	switch (rc) {
195 	case 0: /* Synchronous I/O finished successfully */
196 		cqr->stopclk = get_tod_clock();
197 		cqr->status = DASD_CQR_SUCCESS;
198 		/* Indicate to calling function that only a dasd_schedule_bh()
199 		   and no timer is needed */
200                 rc = -EACCES;
201 		break;
202 	case 8: /* Asynchronous I/O was started */
203 		cqr->status = DASD_CQR_IN_IO;
204 		rc = 0;
205 		break;
206 	default: /* Error condition */
207 		cqr->status = DASD_CQR_QUEUED;
208 		DBF_DEV_EVENT(DBF_WARNING, device, "dia250 returned rc=%d", rc);
209 		dasd_diag_erp(device);
210 		rc = -EIO;
211 		break;
212 	}
213 	cqr->intrc = rc;
214 	return rc;
215 }
216 
217 /* Terminate given request at the device. */
218 static int
219 dasd_diag_term_IO(struct dasd_ccw_req * cqr)
220 {
221 	struct dasd_device *device;
222 
223 	device = cqr->startdev;
224 	mdsk_term_io(device);
225 	mdsk_init_io(device, device->block->bp_block, 0, NULL);
226 	cqr->status = DASD_CQR_CLEAR_PENDING;
227 	cqr->stopclk = get_tod_clock();
228 	dasd_schedule_device_bh(device);
229 	return 0;
230 }
231 
232 /* Handle external interruption. */
233 static void dasd_ext_handler(struct ext_code ext_code,
234 			     unsigned int param32, unsigned long param64)
235 {
236 	struct dasd_ccw_req *cqr, *next;
237 	struct dasd_device *device;
238 	unsigned long expires;
239 	unsigned long flags;
240 	addr_t ip;
241 	int rc;
242 
243 	switch (ext_code.subcode >> 8) {
244 	case DASD_DIAG_CODE_31BIT:
245 		ip = (addr_t) param32;
246 		break;
247 	case DASD_DIAG_CODE_64BIT:
248 		ip = (addr_t) param64;
249 		break;
250 	default:
251 		return;
252 	}
253 	inc_irq_stat(IRQEXT_DSD);
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_tod_clock();
282 
283 	expires = 0;
284 	if ((ext_code.subcode & 0xff) == 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,
300 			      ext_code.subcode & 0xff, 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_diag_private *private = device->private;
319 	struct dasd_diag_characteristics *rdc_data;
320 	struct vtoc_cms_label *label;
321 	struct dasd_block *block;
322 	struct dasd_diag_bio bio;
323 	unsigned int sb, bsize;
324 	blocknum_t end_block;
325 	int rc;
326 
327 	if (private == NULL) {
328 		private = kzalloc(sizeof(*private), GFP_KERNEL);
329 		if (private == NULL) {
330 			DBF_DEV_EVENT(DBF_WARNING, device, "%s",
331 				"Allocating memory for private DASD data "
332 				      "failed\n");
333 			return -ENOMEM;
334 		}
335 		ccw_device_get_id(device->cdev, &private->dev_id);
336 		device->private = private;
337 	}
338 	block = dasd_alloc_block();
339 	if (IS_ERR(block)) {
340 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
341 			    "could not allocate dasd block structure");
342 		device->private = NULL;
343 		kfree(private);
344 		return PTR_ERR(block);
345 	}
346 	device->block = block;
347 	block->base = device;
348 
349 	/* Read Device Characteristics */
350 	rdc_data = &private->rdc_data;
351 	rdc_data->dev_nr = private->dev_id.devno;
352 	rdc_data->rdc_len = sizeof (struct dasd_diag_characteristics);
353 
354 	rc = diag210((struct diag210 *) rdc_data);
355 	if (rc) {
356 		DBF_DEV_EVENT(DBF_WARNING, device, "failed to retrieve device "
357 			    "information (rc=%d)", rc);
358 		rc = -EOPNOTSUPP;
359 		goto out;
360 	}
361 
362 	device->default_expires = DIAG_TIMEOUT;
363 	device->default_retries = DIAG_MAX_RETRIES;
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_warn("%s: Device type %d is not supported in DIAG mode\n",
375 			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_warn("%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_warn("%s: Accessing the DASD failed because of an incorrect format (rc=%d)\n",
428 			dev_name(&device->cdev->dev), rc);
429 		rc = -EIO;
430 		goto out_label;
431 	}
432 	/* check for label block */
433 	if (memcmp(label->label_id, DASD_DIAG_CMS1,
434 		  sizeof(DASD_DIAG_CMS1)) == 0) {
435 		/* get formatted blocksize from label block */
436 		bsize = (unsigned int) label->block_size;
437 		block->blocks = (unsigned long) label->block_count;
438 	} else
439 		block->blocks = end_block;
440 	block->bp_block = bsize;
441 	block->s2b_shift = 0;	/* bits to shift 512 to get a block */
442 	for (sb = 512; sb < bsize; sb = sb << 1)
443 		block->s2b_shift++;
444 	rc = mdsk_init_io(device, block->bp_block, 0, NULL);
445 	if (rc && (rc != 4)) {
446 		pr_warn("%s: DIAG initialization failed with rc=%d\n",
447 			dev_name(&device->cdev->dev), rc);
448 		rc = -EIO;
449 	} else {
450 		if (rc == 4)
451 			set_bit(DASD_FLAG_DEVICE_RO, &device->flags);
452 		pr_info("%s: New DASD with %ld byte/block, total size %ld "
453 			"KB%s\n", dev_name(&device->cdev->dev),
454 			(unsigned long) block->bp_block,
455 			(unsigned long) (block->blocks <<
456 					 block->s2b_shift) >> 1,
457 			(rc == 4) ? ", read-only device" : "");
458 		rc = 0;
459 	}
460 out_label:
461 	free_page((long) label);
462 out:
463 	if (rc) {
464 		device->block = NULL;
465 		dasd_free_block(block);
466 		device->private = NULL;
467 		kfree(private);
468 	}
469 	return rc;
470 }
471 
472 /* Fill in virtual disk geometry for device. Return zero on success, non-zero
473  * otherwise. */
474 static int
475 dasd_diag_fill_geometry(struct dasd_block *block, struct hd_geometry *geo)
476 {
477 	if (dasd_check_blocksize(block->bp_block) != 0)
478 		return -EINVAL;
479 	geo->cylinders = (block->blocks << block->s2b_shift) >> 10;
480 	geo->heads = 16;
481 	geo->sectors = 128 >> block->s2b_shift;
482 	return 0;
483 }
484 
485 static dasd_erp_fn_t
486 dasd_diag_erp_action(struct dasd_ccw_req * cqr)
487 {
488 	return dasd_default_erp_action;
489 }
490 
491 static dasd_erp_fn_t
492 dasd_diag_erp_postaction(struct dasd_ccw_req * cqr)
493 {
494 	return dasd_default_erp_postaction;
495 }
496 
497 /* Create DASD request from block device request. Return pointer to new
498  * request on success, ERR_PTR otherwise. */
499 static struct dasd_ccw_req *dasd_diag_build_cp(struct dasd_device *memdev,
500 					       struct dasd_block *block,
501 					       struct request *req)
502 {
503 	struct dasd_ccw_req *cqr;
504 	struct dasd_diag_req *dreq;
505 	struct dasd_diag_bio *dbio;
506 	struct req_iterator iter;
507 	struct bio_vec bv;
508 	char *dst;
509 	unsigned int count, datasize;
510 	sector_t recid, first_rec, last_rec;
511 	unsigned int blksize, off;
512 	unsigned char rw_cmd;
513 
514 	if (rq_data_dir(req) == READ)
515 		rw_cmd = MDSK_READ_REQ;
516 	else if (rq_data_dir(req) == WRITE)
517 		rw_cmd = MDSK_WRITE_REQ;
518 	else
519 		return ERR_PTR(-EINVAL);
520 	blksize = block->bp_block;
521 	/* Calculate record id of first and last block. */
522 	first_rec = blk_rq_pos(req) >> block->s2b_shift;
523 	last_rec =
524 		(blk_rq_pos(req) + blk_rq_sectors(req) - 1) >> block->s2b_shift;
525 	/* Check struct bio and count the number of blocks for the request. */
526 	count = 0;
527 	rq_for_each_segment(bv, req, iter) {
528 		if (bv.bv_len & (blksize - 1))
529 			/* Fba can only do full blocks. */
530 			return ERR_PTR(-EINVAL);
531 		count += bv.bv_len >> (block->s2b_shift + 9);
532 	}
533 	/* Paranoia. */
534 	if (count != last_rec - first_rec + 1)
535 		return ERR_PTR(-EINVAL);
536 	/* Build the request */
537 	datasize = sizeof(struct dasd_diag_req) +
538 		count*sizeof(struct dasd_diag_bio);
539 	cqr = dasd_smalloc_request(DASD_DIAG_MAGIC, 0, datasize, memdev,
540 				   blk_mq_rq_to_pdu(req));
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 = memdev->default_retries;
561 	cqr->buildclk = get_tod_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 	if (cqr->retries < 0)
588 		cqr->status = DASD_CQR_FAILED;
589 	else
590 		cqr->status = DASD_CQR_FILLED;
591 };
592 
593 /* Fill in IOCTL data for device. */
594 static int
595 dasd_diag_fill_info(struct dasd_device * device,
596 		    struct dasd_information2_t * info)
597 {
598 	struct dasd_diag_private *private = device->private;
599 
600 	info->label_block = (unsigned int) private->pt_block;
601 	info->FBA_layout = 1;
602 	info->format = DASD_FORMAT_LDL;
603 	info->characteristics_size = sizeof(private->rdc_data);
604 	memcpy(info->characteristics, &private->rdc_data,
605 	       sizeof(private->rdc_data));
606 	info->confdata_size = 0;
607 	return 0;
608 }
609 
610 static void
611 dasd_diag_dump_sense(struct dasd_device *device, struct dasd_ccw_req * req,
612 		     struct irb *stat)
613 {
614 	DBF_DEV_EVENT(DBF_WARNING, device, "%s",
615 		    "dump sense not available for DIAG data");
616 }
617 
618 /*
619  * Initialize block layer request queue.
620  */
621 static void dasd_diag_setup_blk_queue(struct dasd_block *block)
622 {
623 	unsigned int logical_block_size = block->bp_block;
624 	struct request_queue *q = block->request_queue;
625 	int max;
626 
627 	max = DIAG_MAX_BLOCKS << block->s2b_shift;
628 	blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
629 	q->limits.max_dev_sectors = max;
630 	blk_queue_logical_block_size(q, logical_block_size);
631 	blk_queue_max_hw_sectors(q, max);
632 	blk_queue_max_segments(q, USHRT_MAX);
633 	/* With page sized segments each segment can be translated into one idaw/tidaw */
634 	blk_queue_max_segment_size(q, PAGE_SIZE);
635 	blk_queue_segment_boundary(q, PAGE_SIZE - 1);
636 }
637 
638 static struct dasd_discipline dasd_diag_discipline = {
639 	.owner = THIS_MODULE,
640 	.name = "DIAG",
641 	.ebcname = "DIAG",
642 	.check_device = dasd_diag_check_device,
643 	.verify_path = dasd_generic_verify_path,
644 	.fill_geometry = dasd_diag_fill_geometry,
645 	.setup_blk_queue = dasd_diag_setup_blk_queue,
646 	.start_IO = dasd_start_diag,
647 	.term_IO = dasd_diag_term_IO,
648 	.handle_terminated_request = dasd_diag_handle_terminated_request,
649 	.erp_action = dasd_diag_erp_action,
650 	.erp_postaction = dasd_diag_erp_postaction,
651 	.build_cp = dasd_diag_build_cp,
652 	.free_cp = dasd_diag_free_cp,
653 	.dump_sense = dasd_diag_dump_sense,
654 	.fill_info = dasd_diag_fill_info,
655 };
656 
657 static int __init
658 dasd_diag_init(void)
659 {
660 	if (!MACHINE_IS_VM) {
661 		pr_info("Discipline %s cannot be used without z/VM\n",
662 			dasd_diag_discipline.name);
663 		return -ENODEV;
664 	}
665 	ASCEBC(dasd_diag_discipline.ebcname, 4);
666 
667 	irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
668 	register_external_irq(EXT_IRQ_CP_SERVICE, dasd_ext_handler);
669 	dasd_diag_discipline_pointer = &dasd_diag_discipline;
670 	return 0;
671 }
672 
673 static void __exit
674 dasd_diag_cleanup(void)
675 {
676 	unregister_external_irq(EXT_IRQ_CP_SERVICE, dasd_ext_handler);
677 	irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
678 	dasd_diag_discipline_pointer = NULL;
679 }
680 
681 module_init(dasd_diag_init);
682 module_exit(dasd_diag_cleanup);
683