1 /*
2 * PAV alias management for the DASD ECKD discipline
3 *
4 * Copyright IBM Corp. 2007
5 * Author(s): Stefan Weinhuber <wein@de.ibm.com>
6 */
7
8 #define KMSG_COMPONENT "dasd-eckd"
9
10 #include <linux/list.h>
11 #include <linux/slab.h>
12 #include <asm/ebcdic.h>
13 #include "dasd_int.h"
14 #include "dasd_eckd.h"
15
16 #ifdef PRINTK_HEADER
17 #undef PRINTK_HEADER
18 #endif /* PRINTK_HEADER */
19 #define PRINTK_HEADER "dasd(eckd):"
20
21
22 /*
23 * General concept of alias management:
24 * - PAV and DASD alias management is specific to the eckd discipline.
25 * - A device is connected to an lcu as long as the device exists.
26 * dasd_alias_make_device_known_to_lcu will be called wenn the
27 * device is checked by the eckd discipline and
28 * dasd_alias_disconnect_device_from_lcu will be called
29 * before the device is deleted.
30 * - The dasd_alias_add_device / dasd_alias_remove_device
31 * functions mark the point when a device is 'ready for service'.
32 * - A summary unit check is a rare occasion, but it is mandatory to
33 * support it. It requires some complex recovery actions before the
34 * devices can be used again (see dasd_alias_handle_summary_unit_check).
35 * - dasd_alias_get_start_dev will find an alias device that can be used
36 * instead of the base device and does some (very simple) load balancing.
37 * This is the function that gets called for each I/O, so when improving
38 * something, this function should get faster or better, the rest has just
39 * to be correct.
40 */
41
42
43 static void summary_unit_check_handling_work(struct work_struct *);
44 static void lcu_update_work(struct work_struct *);
45 static int _schedule_lcu_update(struct alias_lcu *, struct dasd_device *);
46
47 static struct alias_root aliastree = {
48 .serverlist = LIST_HEAD_INIT(aliastree.serverlist),
49 .lock = __SPIN_LOCK_UNLOCKED(aliastree.lock),
50 };
51
_find_server(struct dasd_uid * uid)52 static struct alias_server *_find_server(struct dasd_uid *uid)
53 {
54 struct alias_server *pos;
55 list_for_each_entry(pos, &aliastree.serverlist, server) {
56 if (!strncmp(pos->uid.vendor, uid->vendor,
57 sizeof(uid->vendor))
58 && !strncmp(pos->uid.serial, uid->serial,
59 sizeof(uid->serial)))
60 return pos;
61 };
62 return NULL;
63 }
64
_find_lcu(struct alias_server * server,struct dasd_uid * uid)65 static struct alias_lcu *_find_lcu(struct alias_server *server,
66 struct dasd_uid *uid)
67 {
68 struct alias_lcu *pos;
69 list_for_each_entry(pos, &server->lculist, lcu) {
70 if (pos->uid.ssid == uid->ssid)
71 return pos;
72 };
73 return NULL;
74 }
75
_find_group(struct alias_lcu * lcu,struct dasd_uid * uid)76 static struct alias_pav_group *_find_group(struct alias_lcu *lcu,
77 struct dasd_uid *uid)
78 {
79 struct alias_pav_group *pos;
80 __u8 search_unit_addr;
81
82 /* for hyper pav there is only one group */
83 if (lcu->pav == HYPER_PAV) {
84 if (list_empty(&lcu->grouplist))
85 return NULL;
86 else
87 return list_first_entry(&lcu->grouplist,
88 struct alias_pav_group, group);
89 }
90
91 /* for base pav we have to find the group that matches the base */
92 if (uid->type == UA_BASE_DEVICE)
93 search_unit_addr = uid->real_unit_addr;
94 else
95 search_unit_addr = uid->base_unit_addr;
96 list_for_each_entry(pos, &lcu->grouplist, group) {
97 if (pos->uid.base_unit_addr == search_unit_addr &&
98 !strncmp(pos->uid.vduit, uid->vduit, sizeof(uid->vduit)))
99 return pos;
100 };
101 return NULL;
102 }
103
_allocate_server(struct dasd_uid * uid)104 static struct alias_server *_allocate_server(struct dasd_uid *uid)
105 {
106 struct alias_server *server;
107
108 server = kzalloc(sizeof(*server), GFP_KERNEL);
109 if (!server)
110 return ERR_PTR(-ENOMEM);
111 memcpy(server->uid.vendor, uid->vendor, sizeof(uid->vendor));
112 memcpy(server->uid.serial, uid->serial, sizeof(uid->serial));
113 INIT_LIST_HEAD(&server->server);
114 INIT_LIST_HEAD(&server->lculist);
115 return server;
116 }
117
_free_server(struct alias_server * server)118 static void _free_server(struct alias_server *server)
119 {
120 kfree(server);
121 }
122
_allocate_lcu(struct dasd_uid * uid)123 static struct alias_lcu *_allocate_lcu(struct dasd_uid *uid)
124 {
125 struct alias_lcu *lcu;
126
127 lcu = kzalloc(sizeof(*lcu), GFP_KERNEL);
128 if (!lcu)
129 return ERR_PTR(-ENOMEM);
130 lcu->uac = kzalloc(sizeof(*(lcu->uac)), GFP_KERNEL | GFP_DMA);
131 if (!lcu->uac)
132 goto out_err1;
133 lcu->rsu_cqr = kzalloc(sizeof(*lcu->rsu_cqr), GFP_KERNEL | GFP_DMA);
134 if (!lcu->rsu_cqr)
135 goto out_err2;
136 lcu->rsu_cqr->cpaddr = kzalloc(sizeof(struct ccw1),
137 GFP_KERNEL | GFP_DMA);
138 if (!lcu->rsu_cqr->cpaddr)
139 goto out_err3;
140 lcu->rsu_cqr->data = kzalloc(16, GFP_KERNEL | GFP_DMA);
141 if (!lcu->rsu_cqr->data)
142 goto out_err4;
143
144 memcpy(lcu->uid.vendor, uid->vendor, sizeof(uid->vendor));
145 memcpy(lcu->uid.serial, uid->serial, sizeof(uid->serial));
146 lcu->uid.ssid = uid->ssid;
147 lcu->pav = NO_PAV;
148 lcu->flags = NEED_UAC_UPDATE | UPDATE_PENDING;
149 INIT_LIST_HEAD(&lcu->lcu);
150 INIT_LIST_HEAD(&lcu->inactive_devices);
151 INIT_LIST_HEAD(&lcu->active_devices);
152 INIT_LIST_HEAD(&lcu->grouplist);
153 INIT_WORK(&lcu->suc_data.worker, summary_unit_check_handling_work);
154 INIT_DELAYED_WORK(&lcu->ruac_data.dwork, lcu_update_work);
155 spin_lock_init(&lcu->lock);
156 init_completion(&lcu->lcu_setup);
157 return lcu;
158
159 out_err4:
160 kfree(lcu->rsu_cqr->cpaddr);
161 out_err3:
162 kfree(lcu->rsu_cqr);
163 out_err2:
164 kfree(lcu->uac);
165 out_err1:
166 kfree(lcu);
167 return ERR_PTR(-ENOMEM);
168 }
169
_free_lcu(struct alias_lcu * lcu)170 static void _free_lcu(struct alias_lcu *lcu)
171 {
172 kfree(lcu->rsu_cqr->data);
173 kfree(lcu->rsu_cqr->cpaddr);
174 kfree(lcu->rsu_cqr);
175 kfree(lcu->uac);
176 kfree(lcu);
177 }
178
179 /*
180 * This is the function that will allocate all the server and lcu data,
181 * so this function must be called first for a new device.
182 * If the return value is 1, the lcu was already known before, if it
183 * is 0, this is a new lcu.
184 * Negative return code indicates that something went wrong (e.g. -ENOMEM)
185 */
dasd_alias_make_device_known_to_lcu(struct dasd_device * device)186 int dasd_alias_make_device_known_to_lcu(struct dasd_device *device)
187 {
188 struct dasd_eckd_private *private;
189 unsigned long flags;
190 struct alias_server *server, *newserver;
191 struct alias_lcu *lcu, *newlcu;
192 struct dasd_uid uid;
193
194 private = (struct dasd_eckd_private *) device->private;
195
196 device->discipline->get_uid(device, &uid);
197 spin_lock_irqsave(&aliastree.lock, flags);
198 server = _find_server(&uid);
199 if (!server) {
200 spin_unlock_irqrestore(&aliastree.lock, flags);
201 newserver = _allocate_server(&uid);
202 if (IS_ERR(newserver))
203 return PTR_ERR(newserver);
204 spin_lock_irqsave(&aliastree.lock, flags);
205 server = _find_server(&uid);
206 if (!server) {
207 list_add(&newserver->server, &aliastree.serverlist);
208 server = newserver;
209 } else {
210 /* someone was faster */
211 _free_server(newserver);
212 }
213 }
214
215 lcu = _find_lcu(server, &uid);
216 if (!lcu) {
217 spin_unlock_irqrestore(&aliastree.lock, flags);
218 newlcu = _allocate_lcu(&uid);
219 if (IS_ERR(newlcu))
220 return PTR_ERR(newlcu);
221 spin_lock_irqsave(&aliastree.lock, flags);
222 lcu = _find_lcu(server, &uid);
223 if (!lcu) {
224 list_add(&newlcu->lcu, &server->lculist);
225 lcu = newlcu;
226 } else {
227 /* someone was faster */
228 _free_lcu(newlcu);
229 }
230 }
231 spin_lock(&lcu->lock);
232 list_add(&device->alias_list, &lcu->inactive_devices);
233 private->lcu = lcu;
234 spin_unlock(&lcu->lock);
235 spin_unlock_irqrestore(&aliastree.lock, flags);
236
237 return 0;
238 }
239
240 /*
241 * This function removes a device from the scope of alias management.
242 * The complicated part is to make sure that it is not in use by
243 * any of the workers. If necessary cancel the work.
244 */
dasd_alias_disconnect_device_from_lcu(struct dasd_device * device)245 void dasd_alias_disconnect_device_from_lcu(struct dasd_device *device)
246 {
247 struct dasd_eckd_private *private;
248 unsigned long flags;
249 struct alias_lcu *lcu;
250 struct alias_server *server;
251 int was_pending;
252 struct dasd_uid uid;
253
254 private = (struct dasd_eckd_private *) device->private;
255 lcu = private->lcu;
256 /* nothing to do if already disconnected */
257 if (!lcu)
258 return;
259 device->discipline->get_uid(device, &uid);
260 spin_lock_irqsave(&lcu->lock, flags);
261 list_del_init(&device->alias_list);
262 /* make sure that the workers don't use this device */
263 if (device == lcu->suc_data.device) {
264 spin_unlock_irqrestore(&lcu->lock, flags);
265 cancel_work_sync(&lcu->suc_data.worker);
266 spin_lock_irqsave(&lcu->lock, flags);
267 if (device == lcu->suc_data.device)
268 lcu->suc_data.device = NULL;
269 }
270 was_pending = 0;
271 if (device == lcu->ruac_data.device) {
272 spin_unlock_irqrestore(&lcu->lock, flags);
273 was_pending = 1;
274 cancel_delayed_work_sync(&lcu->ruac_data.dwork);
275 spin_lock_irqsave(&lcu->lock, flags);
276 if (device == lcu->ruac_data.device)
277 lcu->ruac_data.device = NULL;
278 }
279 private->lcu = NULL;
280 spin_unlock_irqrestore(&lcu->lock, flags);
281
282 spin_lock_irqsave(&aliastree.lock, flags);
283 spin_lock(&lcu->lock);
284 if (list_empty(&lcu->grouplist) &&
285 list_empty(&lcu->active_devices) &&
286 list_empty(&lcu->inactive_devices)) {
287 list_del(&lcu->lcu);
288 spin_unlock(&lcu->lock);
289 _free_lcu(lcu);
290 lcu = NULL;
291 } else {
292 if (was_pending)
293 _schedule_lcu_update(lcu, NULL);
294 spin_unlock(&lcu->lock);
295 }
296 server = _find_server(&uid);
297 if (server && list_empty(&server->lculist)) {
298 list_del(&server->server);
299 _free_server(server);
300 }
301 spin_unlock_irqrestore(&aliastree.lock, flags);
302 }
303
304 /*
305 * This function assumes that the unit address configuration stored
306 * in the lcu is up to date and will update the device uid before
307 * adding it to a pav group.
308 */
309
_add_device_to_lcu(struct alias_lcu * lcu,struct dasd_device * device,struct dasd_device * pos)310 static int _add_device_to_lcu(struct alias_lcu *lcu,
311 struct dasd_device *device,
312 struct dasd_device *pos)
313 {
314
315 struct dasd_eckd_private *private;
316 struct alias_pav_group *group;
317 struct dasd_uid uid;
318 unsigned long flags;
319
320 private = (struct dasd_eckd_private *) device->private;
321
322 /* only lock if not already locked */
323 if (device != pos)
324 spin_lock_irqsave_nested(get_ccwdev_lock(device->cdev), flags,
325 CDEV_NESTED_SECOND);
326 private->uid.type = lcu->uac->unit[private->uid.real_unit_addr].ua_type;
327 private->uid.base_unit_addr =
328 lcu->uac->unit[private->uid.real_unit_addr].base_ua;
329 uid = private->uid;
330
331 if (device != pos)
332 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
333
334 /* if we have no PAV anyway, we don't need to bother with PAV groups */
335 if (lcu->pav == NO_PAV) {
336 list_move(&device->alias_list, &lcu->active_devices);
337 return 0;
338 }
339
340 group = _find_group(lcu, &uid);
341 if (!group) {
342 group = kzalloc(sizeof(*group), GFP_ATOMIC);
343 if (!group)
344 return -ENOMEM;
345 memcpy(group->uid.vendor, uid.vendor, sizeof(uid.vendor));
346 memcpy(group->uid.serial, uid.serial, sizeof(uid.serial));
347 group->uid.ssid = uid.ssid;
348 if (uid.type == UA_BASE_DEVICE)
349 group->uid.base_unit_addr = uid.real_unit_addr;
350 else
351 group->uid.base_unit_addr = uid.base_unit_addr;
352 memcpy(group->uid.vduit, uid.vduit, sizeof(uid.vduit));
353 INIT_LIST_HEAD(&group->group);
354 INIT_LIST_HEAD(&group->baselist);
355 INIT_LIST_HEAD(&group->aliaslist);
356 list_add(&group->group, &lcu->grouplist);
357 }
358 if (uid.type == UA_BASE_DEVICE)
359 list_move(&device->alias_list, &group->baselist);
360 else
361 list_move(&device->alias_list, &group->aliaslist);
362 private->pavgroup = group;
363 return 0;
364 };
365
_remove_device_from_lcu(struct alias_lcu * lcu,struct dasd_device * device)366 static void _remove_device_from_lcu(struct alias_lcu *lcu,
367 struct dasd_device *device)
368 {
369 struct dasd_eckd_private *private;
370 struct alias_pav_group *group;
371
372 private = (struct dasd_eckd_private *) device->private;
373 list_move(&device->alias_list, &lcu->inactive_devices);
374 group = private->pavgroup;
375 if (!group)
376 return;
377 private->pavgroup = NULL;
378 if (list_empty(&group->baselist) && list_empty(&group->aliaslist)) {
379 list_del(&group->group);
380 kfree(group);
381 return;
382 }
383 if (group->next == device)
384 group->next = NULL;
385 };
386
387 static int
suborder_not_supported(struct dasd_ccw_req * cqr)388 suborder_not_supported(struct dasd_ccw_req *cqr)
389 {
390 char *sense;
391 char reason;
392 char msg_format;
393 char msg_no;
394
395 sense = dasd_get_sense(&cqr->irb);
396 if (!sense)
397 return 0;
398
399 reason = sense[0];
400 msg_format = (sense[7] & 0xF0);
401 msg_no = (sense[7] & 0x0F);
402
403 /* command reject, Format 0 MSG 4 - invalid parameter */
404 if ((reason == 0x80) && (msg_format == 0x00) && (msg_no == 0x04))
405 return 1;
406
407 return 0;
408 }
409
read_unit_address_configuration(struct dasd_device * device,struct alias_lcu * lcu)410 static int read_unit_address_configuration(struct dasd_device *device,
411 struct alias_lcu *lcu)
412 {
413 struct dasd_psf_prssd_data *prssdp;
414 struct dasd_ccw_req *cqr;
415 struct ccw1 *ccw;
416 int rc;
417 unsigned long flags;
418
419 cqr = dasd_kmalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ + 1 /* RSSD */,
420 (sizeof(struct dasd_psf_prssd_data)),
421 device);
422 if (IS_ERR(cqr))
423 return PTR_ERR(cqr);
424 cqr->startdev = device;
425 cqr->memdev = device;
426 clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
427 cqr->retries = 10;
428 cqr->expires = 20 * HZ;
429
430 /* Prepare for Read Subsystem Data */
431 prssdp = (struct dasd_psf_prssd_data *) cqr->data;
432 memset(prssdp, 0, sizeof(struct dasd_psf_prssd_data));
433 prssdp->order = PSF_ORDER_PRSSD;
434 prssdp->suborder = 0x0e; /* Read unit address configuration */
435 /* all other bytes of prssdp must be zero */
436
437 ccw = cqr->cpaddr;
438 ccw->cmd_code = DASD_ECKD_CCW_PSF;
439 ccw->count = sizeof(struct dasd_psf_prssd_data);
440 ccw->flags |= CCW_FLAG_CC;
441 ccw->cda = (__u32)(addr_t) prssdp;
442
443 /* Read Subsystem Data - feature codes */
444 memset(lcu->uac, 0, sizeof(*(lcu->uac)));
445
446 ccw++;
447 ccw->cmd_code = DASD_ECKD_CCW_RSSD;
448 ccw->count = sizeof(*(lcu->uac));
449 ccw->cda = (__u32)(addr_t) lcu->uac;
450
451 cqr->buildclk = get_tod_clock();
452 cqr->status = DASD_CQR_FILLED;
453
454 /* need to unset flag here to detect race with summary unit check */
455 spin_lock_irqsave(&lcu->lock, flags);
456 lcu->flags &= ~NEED_UAC_UPDATE;
457 spin_unlock_irqrestore(&lcu->lock, flags);
458
459 do {
460 rc = dasd_sleep_on(cqr);
461 if (rc && suborder_not_supported(cqr))
462 return -EOPNOTSUPP;
463 } while (rc && (cqr->retries > 0));
464 if (rc) {
465 spin_lock_irqsave(&lcu->lock, flags);
466 lcu->flags |= NEED_UAC_UPDATE;
467 spin_unlock_irqrestore(&lcu->lock, flags);
468 }
469 dasd_kfree_request(cqr, cqr->memdev);
470 return rc;
471 }
472
_lcu_update(struct dasd_device * refdev,struct alias_lcu * lcu)473 static int _lcu_update(struct dasd_device *refdev, struct alias_lcu *lcu)
474 {
475 unsigned long flags;
476 struct alias_pav_group *pavgroup, *tempgroup;
477 struct dasd_device *device, *tempdev;
478 int i, rc;
479 struct dasd_eckd_private *private;
480
481 spin_lock_irqsave(&lcu->lock, flags);
482 list_for_each_entry_safe(pavgroup, tempgroup, &lcu->grouplist, group) {
483 list_for_each_entry_safe(device, tempdev, &pavgroup->baselist,
484 alias_list) {
485 list_move(&device->alias_list, &lcu->active_devices);
486 private = (struct dasd_eckd_private *) device->private;
487 private->pavgroup = NULL;
488 }
489 list_for_each_entry_safe(device, tempdev, &pavgroup->aliaslist,
490 alias_list) {
491 list_move(&device->alias_list, &lcu->active_devices);
492 private = (struct dasd_eckd_private *) device->private;
493 private->pavgroup = NULL;
494 }
495 list_del(&pavgroup->group);
496 kfree(pavgroup);
497 }
498 spin_unlock_irqrestore(&lcu->lock, flags);
499
500 rc = read_unit_address_configuration(refdev, lcu);
501 if (rc)
502 return rc;
503
504 /* need to take cdev lock before lcu lock */
505 spin_lock_irqsave_nested(get_ccwdev_lock(refdev->cdev), flags,
506 CDEV_NESTED_FIRST);
507 spin_lock(&lcu->lock);
508 lcu->pav = NO_PAV;
509 for (i = 0; i < MAX_DEVICES_PER_LCU; ++i) {
510 switch (lcu->uac->unit[i].ua_type) {
511 case UA_BASE_PAV_ALIAS:
512 lcu->pav = BASE_PAV;
513 break;
514 case UA_HYPER_PAV_ALIAS:
515 lcu->pav = HYPER_PAV;
516 break;
517 }
518 if (lcu->pav != NO_PAV)
519 break;
520 }
521
522 list_for_each_entry_safe(device, tempdev, &lcu->active_devices,
523 alias_list) {
524 _add_device_to_lcu(lcu, device, refdev);
525 }
526 spin_unlock(&lcu->lock);
527 spin_unlock_irqrestore(get_ccwdev_lock(refdev->cdev), flags);
528 return 0;
529 }
530
lcu_update_work(struct work_struct * work)531 static void lcu_update_work(struct work_struct *work)
532 {
533 struct alias_lcu *lcu;
534 struct read_uac_work_data *ruac_data;
535 struct dasd_device *device;
536 unsigned long flags;
537 int rc;
538
539 ruac_data = container_of(work, struct read_uac_work_data, dwork.work);
540 lcu = container_of(ruac_data, struct alias_lcu, ruac_data);
541 device = ruac_data->device;
542 rc = _lcu_update(device, lcu);
543 /*
544 * Need to check flags again, as there could have been another
545 * prepare_update or a new device a new device while we were still
546 * processing the data
547 */
548 spin_lock_irqsave(&lcu->lock, flags);
549 if ((rc && (rc != -EOPNOTSUPP)) || (lcu->flags & NEED_UAC_UPDATE)) {
550 DBF_DEV_EVENT(DBF_WARNING, device, "could not update"
551 " alias data in lcu (rc = %d), retry later", rc);
552 schedule_delayed_work(&lcu->ruac_data.dwork, 30*HZ);
553 } else {
554 lcu->ruac_data.device = NULL;
555 lcu->flags &= ~UPDATE_PENDING;
556 }
557 spin_unlock_irqrestore(&lcu->lock, flags);
558 }
559
_schedule_lcu_update(struct alias_lcu * lcu,struct dasd_device * device)560 static int _schedule_lcu_update(struct alias_lcu *lcu,
561 struct dasd_device *device)
562 {
563 struct dasd_device *usedev = NULL;
564 struct alias_pav_group *group;
565
566 lcu->flags |= NEED_UAC_UPDATE;
567 if (lcu->ruac_data.device) {
568 /* already scheduled or running */
569 return 0;
570 }
571 if (device && !list_empty(&device->alias_list))
572 usedev = device;
573
574 if (!usedev && !list_empty(&lcu->grouplist)) {
575 group = list_first_entry(&lcu->grouplist,
576 struct alias_pav_group, group);
577 if (!list_empty(&group->baselist))
578 usedev = list_first_entry(&group->baselist,
579 struct dasd_device,
580 alias_list);
581 else if (!list_empty(&group->aliaslist))
582 usedev = list_first_entry(&group->aliaslist,
583 struct dasd_device,
584 alias_list);
585 }
586 if (!usedev && !list_empty(&lcu->active_devices)) {
587 usedev = list_first_entry(&lcu->active_devices,
588 struct dasd_device, alias_list);
589 }
590 /*
591 * if we haven't found a proper device yet, give up for now, the next
592 * device that will be set active will trigger an lcu update
593 */
594 if (!usedev)
595 return -EINVAL;
596 lcu->ruac_data.device = usedev;
597 schedule_delayed_work(&lcu->ruac_data.dwork, 0);
598 return 0;
599 }
600
dasd_alias_add_device(struct dasd_device * device)601 int dasd_alias_add_device(struct dasd_device *device)
602 {
603 struct dasd_eckd_private *private;
604 struct alias_lcu *lcu;
605 unsigned long flags;
606 int rc;
607
608 private = (struct dasd_eckd_private *) device->private;
609 lcu = private->lcu;
610 rc = 0;
611
612 /* need to take cdev lock before lcu lock */
613 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
614 spin_lock(&lcu->lock);
615 if (!(lcu->flags & UPDATE_PENDING)) {
616 rc = _add_device_to_lcu(lcu, device, device);
617 if (rc)
618 lcu->flags |= UPDATE_PENDING;
619 }
620 if (lcu->flags & UPDATE_PENDING) {
621 list_move(&device->alias_list, &lcu->active_devices);
622 _schedule_lcu_update(lcu, device);
623 }
624 spin_unlock(&lcu->lock);
625 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
626 return rc;
627 }
628
dasd_alias_update_add_device(struct dasd_device * device)629 int dasd_alias_update_add_device(struct dasd_device *device)
630 {
631 struct dasd_eckd_private *private;
632 private = (struct dasd_eckd_private *) device->private;
633 private->lcu->flags |= UPDATE_PENDING;
634 return dasd_alias_add_device(device);
635 }
636
dasd_alias_remove_device(struct dasd_device * device)637 int dasd_alias_remove_device(struct dasd_device *device)
638 {
639 struct dasd_eckd_private *private;
640 struct alias_lcu *lcu;
641 unsigned long flags;
642
643 private = (struct dasd_eckd_private *) device->private;
644 lcu = private->lcu;
645 /* nothing to do if already removed */
646 if (!lcu)
647 return 0;
648 spin_lock_irqsave(&lcu->lock, flags);
649 _remove_device_from_lcu(lcu, device);
650 spin_unlock_irqrestore(&lcu->lock, flags);
651 return 0;
652 }
653
dasd_alias_get_start_dev(struct dasd_device * base_device)654 struct dasd_device *dasd_alias_get_start_dev(struct dasd_device *base_device)
655 {
656
657 struct dasd_device *alias_device;
658 struct alias_pav_group *group;
659 struct alias_lcu *lcu;
660 struct dasd_eckd_private *private, *alias_priv;
661 unsigned long flags;
662
663 private = (struct dasd_eckd_private *) base_device->private;
664 group = private->pavgroup;
665 lcu = private->lcu;
666 if (!group || !lcu)
667 return NULL;
668 if (lcu->pav == NO_PAV ||
669 lcu->flags & (NEED_UAC_UPDATE | UPDATE_PENDING))
670 return NULL;
671 if (unlikely(!(private->features.feature[8] & 0x01))) {
672 /*
673 * PAV enabled but prefix not, very unlikely
674 * seems to be a lost pathgroup
675 * use base device to do IO
676 */
677 DBF_DEV_EVENT(DBF_ERR, base_device, "%s",
678 "Prefix not enabled with PAV enabled\n");
679 return NULL;
680 }
681
682 spin_lock_irqsave(&lcu->lock, flags);
683 alias_device = group->next;
684 if (!alias_device) {
685 if (list_empty(&group->aliaslist)) {
686 spin_unlock_irqrestore(&lcu->lock, flags);
687 return NULL;
688 } else {
689 alias_device = list_first_entry(&group->aliaslist,
690 struct dasd_device,
691 alias_list);
692 }
693 }
694 if (list_is_last(&alias_device->alias_list, &group->aliaslist))
695 group->next = list_first_entry(&group->aliaslist,
696 struct dasd_device, alias_list);
697 else
698 group->next = list_first_entry(&alias_device->alias_list,
699 struct dasd_device, alias_list);
700 spin_unlock_irqrestore(&lcu->lock, flags);
701 alias_priv = (struct dasd_eckd_private *) alias_device->private;
702 if ((alias_priv->count < private->count) && !alias_device->stopped)
703 return alias_device;
704 else
705 return NULL;
706 }
707
708 /*
709 * Summary unit check handling depends on the way alias devices
710 * are handled so it is done here rather then in dasd_eckd.c
711 */
reset_summary_unit_check(struct alias_lcu * lcu,struct dasd_device * device,char reason)712 static int reset_summary_unit_check(struct alias_lcu *lcu,
713 struct dasd_device *device,
714 char reason)
715 {
716 struct dasd_ccw_req *cqr;
717 int rc = 0;
718 struct ccw1 *ccw;
719
720 cqr = lcu->rsu_cqr;
721 strncpy((char *) &cqr->magic, "ECKD", 4);
722 ASCEBC((char *) &cqr->magic, 4);
723 ccw = cqr->cpaddr;
724 ccw->cmd_code = DASD_ECKD_CCW_RSCK;
725 ccw->flags = 0 ;
726 ccw->count = 16;
727 ccw->cda = (__u32)(addr_t) cqr->data;
728 ((char *)cqr->data)[0] = reason;
729
730 clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
731 cqr->retries = 255; /* set retry counter to enable basic ERP */
732 cqr->startdev = device;
733 cqr->memdev = device;
734 cqr->block = NULL;
735 cqr->expires = 5 * HZ;
736 cqr->buildclk = get_tod_clock();
737 cqr->status = DASD_CQR_FILLED;
738
739 rc = dasd_sleep_on_immediatly(cqr);
740 return rc;
741 }
742
_restart_all_base_devices_on_lcu(struct alias_lcu * lcu)743 static void _restart_all_base_devices_on_lcu(struct alias_lcu *lcu)
744 {
745 struct alias_pav_group *pavgroup;
746 struct dasd_device *device;
747 struct dasd_eckd_private *private;
748 unsigned long flags;
749
750 /* active and inactive list can contain alias as well as base devices */
751 list_for_each_entry(device, &lcu->active_devices, alias_list) {
752 private = (struct dasd_eckd_private *) device->private;
753 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
754 if (private->uid.type != UA_BASE_DEVICE) {
755 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
756 flags);
757 continue;
758 }
759 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
760 dasd_schedule_block_bh(device->block);
761 dasd_schedule_device_bh(device);
762 }
763 list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
764 private = (struct dasd_eckd_private *) device->private;
765 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
766 if (private->uid.type != UA_BASE_DEVICE) {
767 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
768 flags);
769 continue;
770 }
771 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
772 dasd_schedule_block_bh(device->block);
773 dasd_schedule_device_bh(device);
774 }
775 list_for_each_entry(pavgroup, &lcu->grouplist, group) {
776 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
777 dasd_schedule_block_bh(device->block);
778 dasd_schedule_device_bh(device);
779 }
780 }
781 }
782
flush_all_alias_devices_on_lcu(struct alias_lcu * lcu)783 static void flush_all_alias_devices_on_lcu(struct alias_lcu *lcu)
784 {
785 struct alias_pav_group *pavgroup;
786 struct dasd_device *device, *temp;
787 struct dasd_eckd_private *private;
788 int rc;
789 unsigned long flags;
790 LIST_HEAD(active);
791
792 /*
793 * Problem here ist that dasd_flush_device_queue may wait
794 * for termination of a request to complete. We can't keep
795 * the lcu lock during that time, so we must assume that
796 * the lists may have changed.
797 * Idea: first gather all active alias devices in a separate list,
798 * then flush the first element of this list unlocked, and afterwards
799 * check if it is still on the list before moving it to the
800 * active_devices list.
801 */
802
803 spin_lock_irqsave(&lcu->lock, flags);
804 list_for_each_entry_safe(device, temp, &lcu->active_devices,
805 alias_list) {
806 private = (struct dasd_eckd_private *) device->private;
807 if (private->uid.type == UA_BASE_DEVICE)
808 continue;
809 list_move(&device->alias_list, &active);
810 }
811
812 list_for_each_entry(pavgroup, &lcu->grouplist, group) {
813 list_splice_init(&pavgroup->aliaslist, &active);
814 }
815 while (!list_empty(&active)) {
816 device = list_first_entry(&active, struct dasd_device,
817 alias_list);
818 spin_unlock_irqrestore(&lcu->lock, flags);
819 rc = dasd_flush_device_queue(device);
820 spin_lock_irqsave(&lcu->lock, flags);
821 /*
822 * only move device around if it wasn't moved away while we
823 * were waiting for the flush
824 */
825 if (device == list_first_entry(&active,
826 struct dasd_device, alias_list))
827 list_move(&device->alias_list, &lcu->active_devices);
828 }
829 spin_unlock_irqrestore(&lcu->lock, flags);
830 }
831
__stop_device_on_lcu(struct dasd_device * device,struct dasd_device * pos)832 static void __stop_device_on_lcu(struct dasd_device *device,
833 struct dasd_device *pos)
834 {
835 /* If pos == device then device is already locked! */
836 if (pos == device) {
837 dasd_device_set_stop_bits(pos, DASD_STOPPED_SU);
838 return;
839 }
840 spin_lock(get_ccwdev_lock(pos->cdev));
841 dasd_device_set_stop_bits(pos, DASD_STOPPED_SU);
842 spin_unlock(get_ccwdev_lock(pos->cdev));
843 }
844
845 /*
846 * This function is called in interrupt context, so the
847 * cdev lock for device is already locked!
848 */
_stop_all_devices_on_lcu(struct alias_lcu * lcu,struct dasd_device * device)849 static void _stop_all_devices_on_lcu(struct alias_lcu *lcu,
850 struct dasd_device *device)
851 {
852 struct alias_pav_group *pavgroup;
853 struct dasd_device *pos;
854
855 list_for_each_entry(pos, &lcu->active_devices, alias_list)
856 __stop_device_on_lcu(device, pos);
857 list_for_each_entry(pos, &lcu->inactive_devices, alias_list)
858 __stop_device_on_lcu(device, pos);
859 list_for_each_entry(pavgroup, &lcu->grouplist, group) {
860 list_for_each_entry(pos, &pavgroup->baselist, alias_list)
861 __stop_device_on_lcu(device, pos);
862 list_for_each_entry(pos, &pavgroup->aliaslist, alias_list)
863 __stop_device_on_lcu(device, pos);
864 }
865 }
866
_unstop_all_devices_on_lcu(struct alias_lcu * lcu)867 static void _unstop_all_devices_on_lcu(struct alias_lcu *lcu)
868 {
869 struct alias_pav_group *pavgroup;
870 struct dasd_device *device;
871 unsigned long flags;
872
873 list_for_each_entry(device, &lcu->active_devices, alias_list) {
874 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
875 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
876 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
877 }
878
879 list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
880 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
881 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
882 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
883 }
884
885 list_for_each_entry(pavgroup, &lcu->grouplist, group) {
886 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
887 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
888 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
889 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
890 flags);
891 }
892 list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
893 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
894 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
895 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
896 flags);
897 }
898 }
899 }
900
summary_unit_check_handling_work(struct work_struct * work)901 static void summary_unit_check_handling_work(struct work_struct *work)
902 {
903 struct alias_lcu *lcu;
904 struct summary_unit_check_work_data *suc_data;
905 unsigned long flags;
906 struct dasd_device *device;
907
908 suc_data = container_of(work, struct summary_unit_check_work_data,
909 worker);
910 lcu = container_of(suc_data, struct alias_lcu, suc_data);
911 device = suc_data->device;
912
913 /* 1. flush alias devices */
914 flush_all_alias_devices_on_lcu(lcu);
915
916 /* 2. reset summary unit check */
917 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
918 dasd_device_remove_stop_bits(device,
919 (DASD_STOPPED_SU | DASD_STOPPED_PENDING));
920 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
921 reset_summary_unit_check(lcu, device, suc_data->reason);
922
923 spin_lock_irqsave(&lcu->lock, flags);
924 _unstop_all_devices_on_lcu(lcu);
925 _restart_all_base_devices_on_lcu(lcu);
926 /* 3. read new alias configuration */
927 _schedule_lcu_update(lcu, device);
928 lcu->suc_data.device = NULL;
929 spin_unlock_irqrestore(&lcu->lock, flags);
930 }
931
932 /*
933 * note: this will be called from int handler context (cdev locked)
934 */
dasd_alias_handle_summary_unit_check(struct dasd_device * device,struct irb * irb)935 void dasd_alias_handle_summary_unit_check(struct dasd_device *device,
936 struct irb *irb)
937 {
938 struct alias_lcu *lcu;
939 char reason;
940 struct dasd_eckd_private *private;
941 char *sense;
942
943 private = (struct dasd_eckd_private *) device->private;
944
945 sense = dasd_get_sense(irb);
946 if (sense) {
947 reason = sense[8];
948 DBF_DEV_EVENT(DBF_NOTICE, device, "%s %x",
949 "eckd handle summary unit check: reason", reason);
950 } else {
951 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
952 "eckd handle summary unit check:"
953 " no reason code available");
954 return;
955 }
956
957 lcu = private->lcu;
958 if (!lcu) {
959 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
960 "device not ready to handle summary"
961 " unit check (no lcu structure)");
962 return;
963 }
964 spin_lock(&lcu->lock);
965 _stop_all_devices_on_lcu(lcu, device);
966 /* prepare for lcu_update */
967 private->lcu->flags |= NEED_UAC_UPDATE | UPDATE_PENDING;
968 /* If this device is about to be removed just return and wait for
969 * the next interrupt on a different device
970 */
971 if (list_empty(&device->alias_list)) {
972 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
973 "device is in offline processing,"
974 " don't do summary unit check handling");
975 spin_unlock(&lcu->lock);
976 return;
977 }
978 if (lcu->suc_data.device) {
979 /* already scheduled or running */
980 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
981 "previous instance of summary unit check worker"
982 " still pending");
983 spin_unlock(&lcu->lock);
984 return ;
985 }
986 lcu->suc_data.reason = reason;
987 lcu->suc_data.device = device;
988 spin_unlock(&lcu->lock);
989 schedule_work(&lcu->suc_data.worker);
990 };
991