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7
8#include <linux/slab.h>
9#include <linux/delay.h>
10#include <linux/module.h>
11#include <asm/unaligned.h>
12#include <scsi/scsi.h>
13#include <scsi/scsi_proto.h>
14#include <scsi/scsi_dbg.h>
15#include <scsi/scsi_eh.h>
16#include <scsi/scsi_dh.h>
17
18#define ALUA_DH_NAME "alua"
19#define ALUA_DH_VER "2.0"
20
21#define TPGS_SUPPORT_NONE 0x00
22#define TPGS_SUPPORT_OPTIMIZED 0x01
23#define TPGS_SUPPORT_NONOPTIMIZED 0x02
24#define TPGS_SUPPORT_STANDBY 0x04
25#define TPGS_SUPPORT_UNAVAILABLE 0x08
26#define TPGS_SUPPORT_LBA_DEPENDENT 0x10
27#define TPGS_SUPPORT_OFFLINE 0x40
28#define TPGS_SUPPORT_TRANSITION 0x80
29#define TPGS_SUPPORT_ALL 0xdf
30
31#define RTPG_FMT_MASK 0x70
32#define RTPG_FMT_EXT_HDR 0x10
33
34#define TPGS_MODE_UNINITIALIZED -1
35#define TPGS_MODE_NONE 0x0
36#define TPGS_MODE_IMPLICIT 0x1
37#define TPGS_MODE_EXPLICIT 0x2
38
39#define ALUA_RTPG_SIZE 128
40#define ALUA_FAILOVER_TIMEOUT 60
41#define ALUA_FAILOVER_RETRIES 5
42#define ALUA_RTPG_DELAY_MSECS 5
43#define ALUA_RTPG_RETRY_DELAY 2
44
45
46#define ALUA_OPTIMIZE_STPG 0x01
47#define ALUA_RTPG_EXT_HDR_UNSUPP 0x02
48
49#define ALUA_PG_RUN_RTPG 0x10
50#define ALUA_PG_RUN_STPG 0x20
51#define ALUA_PG_RUNNING 0x40
52
53static uint optimize_stpg;
54module_param(optimize_stpg, uint, S_IRUGO|S_IWUSR);
55MODULE_PARM_DESC(optimize_stpg, "Allow use of a non-optimized path, rather than sending a STPG, when implicit TPGS is supported (0=No,1=Yes). Default is 0.");
56
57static LIST_HEAD(port_group_list);
58static DEFINE_SPINLOCK(port_group_lock);
59static struct workqueue_struct *kaluad_wq;
60
61struct alua_port_group {
62 struct kref kref;
63 struct rcu_head rcu;
64 struct list_head node;
65 struct list_head dh_list;
66 unsigned char device_id_str[256];
67 int device_id_len;
68 int group_id;
69 int tpgs;
70 int state;
71 int pref;
72 int valid_states;
73 unsigned flags;
74 unsigned char transition_tmo;
75 unsigned long expiry;
76 unsigned long interval;
77 struct delayed_work rtpg_work;
78 spinlock_t lock;
79 struct list_head rtpg_list;
80 struct scsi_device *rtpg_sdev;
81};
82
83struct alua_dh_data {
84 struct list_head node;
85 struct alua_port_group __rcu *pg;
86 int group_id;
87 spinlock_t pg_lock;
88 struct scsi_device *sdev;
89 int init_error;
90 struct mutex init_mutex;
91};
92
93struct alua_queue_data {
94 struct list_head entry;
95 activate_complete callback_fn;
96 void *callback_data;
97};
98
99#define ALUA_POLICY_SWITCH_CURRENT 0
100#define ALUA_POLICY_SWITCH_ALL 1
101
102static void alua_rtpg_work(struct work_struct *work);
103static bool alua_rtpg_queue(struct alua_port_group *pg,
104 struct scsi_device *sdev,
105 struct alua_queue_data *qdata, bool force);
106static void alua_check(struct scsi_device *sdev, bool force);
107
108static void release_port_group(struct kref *kref)
109{
110 struct alua_port_group *pg;
111
112 pg = container_of(kref, struct alua_port_group, kref);
113 if (pg->rtpg_sdev)
114 flush_delayed_work(&pg->rtpg_work);
115 spin_lock(&port_group_lock);
116 list_del(&pg->node);
117 spin_unlock(&port_group_lock);
118 kfree_rcu(pg, rcu);
119}
120
121
122
123
124
125static int submit_rtpg(struct scsi_device *sdev, unsigned char *buff,
126 int bufflen, struct scsi_sense_hdr *sshdr, int flags)
127{
128 u8 cdb[MAX_COMMAND_SIZE];
129 int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
130 REQ_FAILFAST_DRIVER;
131
132
133 memset(cdb, 0x0, MAX_COMMAND_SIZE);
134 cdb[0] = MAINTENANCE_IN;
135 if (!(flags & ALUA_RTPG_EXT_HDR_UNSUPP))
136 cdb[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT;
137 else
138 cdb[1] = MI_REPORT_TARGET_PGS;
139 put_unaligned_be32(bufflen, &cdb[6]);
140
141 return scsi_execute(sdev, cdb, DMA_FROM_DEVICE, buff, bufflen, NULL,
142 sshdr, ALUA_FAILOVER_TIMEOUT * HZ,
143 ALUA_FAILOVER_RETRIES, req_flags, 0, NULL);
144}
145
146
147
148
149
150
151
152
153static int submit_stpg(struct scsi_device *sdev, int group_id,
154 struct scsi_sense_hdr *sshdr)
155{
156 u8 cdb[MAX_COMMAND_SIZE];
157 unsigned char stpg_data[8];
158 int stpg_len = 8;
159 int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
160 REQ_FAILFAST_DRIVER;
161
162
163 memset(stpg_data, 0, stpg_len);
164 stpg_data[4] = SCSI_ACCESS_STATE_OPTIMAL;
165 put_unaligned_be16(group_id, &stpg_data[6]);
166
167
168 memset(cdb, 0x0, MAX_COMMAND_SIZE);
169 cdb[0] = MAINTENANCE_OUT;
170 cdb[1] = MO_SET_TARGET_PGS;
171 put_unaligned_be32(stpg_len, &cdb[6]);
172
173 return scsi_execute(sdev, cdb, DMA_TO_DEVICE, stpg_data, stpg_len, NULL,
174 sshdr, ALUA_FAILOVER_TIMEOUT * HZ,
175 ALUA_FAILOVER_RETRIES, req_flags, 0, NULL);
176}
177
178static struct alua_port_group *alua_find_get_pg(char *id_str, size_t id_size,
179 int group_id)
180{
181 struct alua_port_group *pg;
182
183 if (!id_str || !id_size || !strlen(id_str))
184 return NULL;
185
186 list_for_each_entry(pg, &port_group_list, node) {
187 if (pg->group_id != group_id)
188 continue;
189 if (!pg->device_id_len || pg->device_id_len != id_size)
190 continue;
191 if (strncmp(pg->device_id_str, id_str, id_size))
192 continue;
193 if (!kref_get_unless_zero(&pg->kref))
194 continue;
195 return pg;
196 }
197
198 return NULL;
199}
200
201
202
203
204
205
206
207
208
209
210static struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev,
211 int group_id, int tpgs)
212{
213 struct alua_port_group *pg, *tmp_pg;
214
215 pg = kzalloc(sizeof(struct alua_port_group), GFP_KERNEL);
216 if (!pg)
217 return ERR_PTR(-ENOMEM);
218
219 pg->device_id_len = scsi_vpd_lun_id(sdev, pg->device_id_str,
220 sizeof(pg->device_id_str));
221 if (pg->device_id_len <= 0) {
222
223
224
225
226 sdev_printk(KERN_INFO, sdev,
227 "%s: No device descriptors found\n",
228 ALUA_DH_NAME);
229 pg->device_id_str[0] = '\0';
230 pg->device_id_len = 0;
231 }
232 pg->group_id = group_id;
233 pg->tpgs = tpgs;
234 pg->state = SCSI_ACCESS_STATE_OPTIMAL;
235 pg->valid_states = TPGS_SUPPORT_ALL;
236 if (optimize_stpg)
237 pg->flags |= ALUA_OPTIMIZE_STPG;
238 kref_init(&pg->kref);
239 INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work);
240 INIT_LIST_HEAD(&pg->rtpg_list);
241 INIT_LIST_HEAD(&pg->node);
242 INIT_LIST_HEAD(&pg->dh_list);
243 spin_lock_init(&pg->lock);
244
245 spin_lock(&port_group_lock);
246 tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len,
247 group_id);
248 if (tmp_pg) {
249 spin_unlock(&port_group_lock);
250 kfree(pg);
251 return tmp_pg;
252 }
253
254 list_add(&pg->node, &port_group_list);
255 spin_unlock(&port_group_lock);
256
257 return pg;
258}
259
260
261
262
263
264
265
266
267static int alua_check_tpgs(struct scsi_device *sdev)
268{
269 int tpgs = TPGS_MODE_NONE;
270
271
272
273
274
275 if (sdev->type != TYPE_DISK) {
276 sdev_printk(KERN_INFO, sdev,
277 "%s: disable for non-disk devices\n",
278 ALUA_DH_NAME);
279 return tpgs;
280 }
281
282 tpgs = scsi_device_tpgs(sdev);
283 switch (tpgs) {
284 case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
285 sdev_printk(KERN_INFO, sdev,
286 "%s: supports implicit and explicit TPGS\n",
287 ALUA_DH_NAME);
288 break;
289 case TPGS_MODE_EXPLICIT:
290 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n",
291 ALUA_DH_NAME);
292 break;
293 case TPGS_MODE_IMPLICIT:
294 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n",
295 ALUA_DH_NAME);
296 break;
297 case TPGS_MODE_NONE:
298 sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
299 ALUA_DH_NAME);
300 break;
301 default:
302 sdev_printk(KERN_INFO, sdev,
303 "%s: unsupported TPGS setting %d\n",
304 ALUA_DH_NAME, tpgs);
305 tpgs = TPGS_MODE_NONE;
306 break;
307 }
308
309 return tpgs;
310}
311
312
313
314
315
316
317
318
319static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h,
320 int tpgs)
321{
322 int rel_port = -1, group_id;
323 struct alua_port_group *pg, *old_pg = NULL;
324 bool pg_updated = false;
325 unsigned long flags;
326
327 group_id = scsi_vpd_tpg_id(sdev, &rel_port);
328 if (group_id < 0) {
329
330
331
332
333
334 sdev_printk(KERN_INFO, sdev,
335 "%s: No target port descriptors found\n",
336 ALUA_DH_NAME);
337 return SCSI_DH_DEV_UNSUPP;
338 }
339
340 pg = alua_alloc_pg(sdev, group_id, tpgs);
341 if (IS_ERR(pg)) {
342 if (PTR_ERR(pg) == -ENOMEM)
343 return SCSI_DH_NOMEM;
344 return SCSI_DH_DEV_UNSUPP;
345 }
346 if (pg->device_id_len)
347 sdev_printk(KERN_INFO, sdev,
348 "%s: device %s port group %x rel port %x\n",
349 ALUA_DH_NAME, pg->device_id_str,
350 group_id, rel_port);
351 else
352 sdev_printk(KERN_INFO, sdev,
353 "%s: port group %x rel port %x\n",
354 ALUA_DH_NAME, group_id, rel_port);
355
356
357 spin_lock(&h->pg_lock);
358 old_pg = rcu_dereference_protected(h->pg, lockdep_is_held(&h->pg_lock));
359 if (old_pg != pg) {
360
361 if (h->pg) {
362 spin_lock_irqsave(&old_pg->lock, flags);
363 list_del_rcu(&h->node);
364 spin_unlock_irqrestore(&old_pg->lock, flags);
365 }
366 rcu_assign_pointer(h->pg, pg);
367 pg_updated = true;
368 }
369
370 spin_lock_irqsave(&pg->lock, flags);
371 if (pg_updated)
372 list_add_rcu(&h->node, &pg->dh_list);
373 spin_unlock_irqrestore(&pg->lock, flags);
374
375 alua_rtpg_queue(rcu_dereference_protected(h->pg,
376 lockdep_is_held(&h->pg_lock)),
377 sdev, NULL, true);
378 spin_unlock(&h->pg_lock);
379
380 if (old_pg)
381 kref_put(&old_pg->kref, release_port_group);
382
383 return SCSI_DH_OK;
384}
385
386static char print_alua_state(unsigned char state)
387{
388 switch (state) {
389 case SCSI_ACCESS_STATE_OPTIMAL:
390 return 'A';
391 case SCSI_ACCESS_STATE_ACTIVE:
392 return 'N';
393 case SCSI_ACCESS_STATE_STANDBY:
394 return 'S';
395 case SCSI_ACCESS_STATE_UNAVAILABLE:
396 return 'U';
397 case SCSI_ACCESS_STATE_LBA:
398 return 'L';
399 case SCSI_ACCESS_STATE_OFFLINE:
400 return 'O';
401 case SCSI_ACCESS_STATE_TRANSITIONING:
402 return 'T';
403 default:
404 return 'X';
405 }
406}
407
408static int alua_check_sense(struct scsi_device *sdev,
409 struct scsi_sense_hdr *sense_hdr)
410{
411 switch (sense_hdr->sense_key) {
412 case NOT_READY:
413 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) {
414
415
416
417 alua_check(sdev, false);
418 return NEEDS_RETRY;
419 }
420 break;
421 case UNIT_ATTENTION:
422 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) {
423
424
425
426
427
428 alua_check(sdev, true);
429 return ADD_TO_MLQUEUE;
430 }
431 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x04)
432
433
434
435 return ADD_TO_MLQUEUE;
436 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01)
437
438
439
440 return ADD_TO_MLQUEUE;
441 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
442
443
444
445 alua_check(sdev, true);
446 return ADD_TO_MLQUEUE;
447 }
448 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
449
450
451
452 alua_check(sdev, true);
453 return ADD_TO_MLQUEUE;
454 }
455 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03)
456
457
458
459 return ADD_TO_MLQUEUE;
460 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e)
461
462
463
464
465
466 return ADD_TO_MLQUEUE;
467 break;
468 }
469
470 return SCSI_RETURN_NOT_HANDLED;
471}
472
473
474
475
476
477
478
479
480
481static int alua_tur(struct scsi_device *sdev)
482{
483 struct scsi_sense_hdr sense_hdr;
484 int retval;
485
486 retval = scsi_test_unit_ready(sdev, ALUA_FAILOVER_TIMEOUT * HZ,
487 ALUA_FAILOVER_RETRIES, &sense_hdr);
488 if (sense_hdr.sense_key == NOT_READY &&
489 sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a)
490 return SCSI_DH_RETRY;
491 else if (retval)
492 return SCSI_DH_IO;
493 else
494 return SCSI_DH_OK;
495}
496
497
498
499
500
501
502
503
504
505static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
506{
507 struct scsi_sense_hdr sense_hdr;
508 struct alua_port_group *tmp_pg;
509 int len, k, off, bufflen = ALUA_RTPG_SIZE;
510 unsigned char *desc, *buff;
511 unsigned err, retval;
512 unsigned int tpg_desc_tbl_off;
513 unsigned char orig_transition_tmo;
514 unsigned long flags;
515
516 if (!pg->expiry) {
517 unsigned long transition_tmo = ALUA_FAILOVER_TIMEOUT * HZ;
518
519 if (pg->transition_tmo)
520 transition_tmo = pg->transition_tmo * HZ;
521
522 pg->expiry = round_jiffies_up(jiffies + transition_tmo);
523 }
524
525 buff = kzalloc(bufflen, GFP_KERNEL);
526 if (!buff)
527 return SCSI_DH_DEV_TEMP_BUSY;
528
529 retry:
530 err = 0;
531 retval = submit_rtpg(sdev, buff, bufflen, &sense_hdr, pg->flags);
532
533 if (retval) {
534
535
536
537
538
539
540
541
542
543 if ((pg->valid_states & ~TPGS_SUPPORT_OPTIMIZED) == 0) {
544 sdev_printk(KERN_INFO, sdev,
545 "%s: ignoring rtpg result %d\n",
546 ALUA_DH_NAME, retval);
547 kfree(buff);
548 return SCSI_DH_OK;
549 }
550 if (!scsi_sense_valid(&sense_hdr)) {
551 sdev_printk(KERN_INFO, sdev,
552 "%s: rtpg failed, result %d\n",
553 ALUA_DH_NAME, retval);
554 kfree(buff);
555 if (driver_byte(retval) == DRIVER_ERROR)
556 return SCSI_DH_DEV_TEMP_BUSY;
557 return SCSI_DH_IO;
558 }
559
560
561
562
563
564
565
566
567
568 if (!(pg->flags & ALUA_RTPG_EXT_HDR_UNSUPP) &&
569 sense_hdr.sense_key == ILLEGAL_REQUEST &&
570 sense_hdr.asc == 0x24 && sense_hdr.ascq == 0) {
571 pg->flags |= ALUA_RTPG_EXT_HDR_UNSUPP;
572 goto retry;
573 }
574
575
576
577
578 if (sense_hdr.sense_key == NOT_READY &&
579 sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a)
580 err = SCSI_DH_RETRY;
581 else if (sense_hdr.sense_key == UNIT_ATTENTION)
582 err = SCSI_DH_RETRY;
583 if (err == SCSI_DH_RETRY &&
584 pg->expiry != 0 && time_before(jiffies, pg->expiry)) {
585 sdev_printk(KERN_ERR, sdev, "%s: rtpg retry\n",
586 ALUA_DH_NAME);
587 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
588 kfree(buff);
589 return err;
590 }
591 sdev_printk(KERN_ERR, sdev, "%s: rtpg failed\n",
592 ALUA_DH_NAME);
593 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
594 kfree(buff);
595 pg->expiry = 0;
596 return SCSI_DH_IO;
597 }
598
599 len = get_unaligned_be32(&buff[0]) + 4;
600
601 if (len > bufflen) {
602
603 kfree(buff);
604 bufflen = len;
605 buff = kmalloc(bufflen, GFP_KERNEL);
606 if (!buff) {
607 sdev_printk(KERN_WARNING, sdev,
608 "%s: kmalloc buffer failed\n",__func__);
609
610 pg->expiry = 0;
611 return SCSI_DH_DEV_TEMP_BUSY;
612 }
613 goto retry;
614 }
615
616 orig_transition_tmo = pg->transition_tmo;
617 if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && buff[5] != 0)
618 pg->transition_tmo = buff[5];
619 else
620 pg->transition_tmo = ALUA_FAILOVER_TIMEOUT;
621
622 if (orig_transition_tmo != pg->transition_tmo) {
623 sdev_printk(KERN_INFO, sdev,
624 "%s: transition timeout set to %d seconds\n",
625 ALUA_DH_NAME, pg->transition_tmo);
626 pg->expiry = jiffies + pg->transition_tmo * HZ;
627 }
628
629 if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR)
630 tpg_desc_tbl_off = 8;
631 else
632 tpg_desc_tbl_off = 4;
633
634 for (k = tpg_desc_tbl_off, desc = buff + tpg_desc_tbl_off;
635 k < len;
636 k += off, desc += off) {
637 u16 group_id = get_unaligned_be16(&desc[2]);
638
639 spin_lock_irqsave(&port_group_lock, flags);
640 tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len,
641 group_id);
642 spin_unlock_irqrestore(&port_group_lock, flags);
643 if (tmp_pg) {
644 if (spin_trylock_irqsave(&tmp_pg->lock, flags)) {
645 if ((tmp_pg == pg) ||
646 !(tmp_pg->flags & ALUA_PG_RUNNING)) {
647 struct alua_dh_data *h;
648
649 tmp_pg->state = desc[0] & 0x0f;
650 tmp_pg->pref = desc[0] >> 7;
651 rcu_read_lock();
652 list_for_each_entry_rcu(h,
653 &tmp_pg->dh_list, node) {
654
655 BUG_ON(!h->sdev);
656 h->sdev->access_state = desc[0];
657 }
658 rcu_read_unlock();
659 }
660 if (tmp_pg == pg)
661 tmp_pg->valid_states = desc[1];
662 spin_unlock_irqrestore(&tmp_pg->lock, flags);
663 }
664 kref_put(&tmp_pg->kref, release_port_group);
665 }
666 off = 8 + (desc[7] * 4);
667 }
668
669 spin_lock_irqsave(&pg->lock, flags);
670 sdev_printk(KERN_INFO, sdev,
671 "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n",
672 ALUA_DH_NAME, pg->group_id, print_alua_state(pg->state),
673 pg->pref ? "preferred" : "non-preferred",
674 pg->valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
675 pg->valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
676 pg->valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
677 pg->valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
678 pg->valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
679 pg->valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
680 pg->valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
681
682 switch (pg->state) {
683 case SCSI_ACCESS_STATE_TRANSITIONING:
684 if (time_before(jiffies, pg->expiry)) {
685
686 pg->interval = ALUA_RTPG_RETRY_DELAY;
687 err = SCSI_DH_RETRY;
688 } else {
689 struct alua_dh_data *h;
690
691
692 err = SCSI_DH_IO;
693 pg->state = SCSI_ACCESS_STATE_STANDBY;
694 pg->expiry = 0;
695 rcu_read_lock();
696 list_for_each_entry_rcu(h, &pg->dh_list, node) {
697 BUG_ON(!h->sdev);
698 h->sdev->access_state =
699 (pg->state & SCSI_ACCESS_STATE_MASK);
700 if (pg->pref)
701 h->sdev->access_state |=
702 SCSI_ACCESS_STATE_PREFERRED;
703 }
704 rcu_read_unlock();
705 }
706 break;
707 case SCSI_ACCESS_STATE_OFFLINE:
708
709 err = SCSI_DH_DEV_OFFLINED;
710 pg->expiry = 0;
711 break;
712 default:
713
714 err = SCSI_DH_OK;
715 pg->expiry = 0;
716 break;
717 }
718 spin_unlock_irqrestore(&pg->lock, flags);
719 kfree(buff);
720 return err;
721}
722
723
724
725
726
727
728
729
730
731static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
732{
733 int retval;
734 struct scsi_sense_hdr sense_hdr;
735
736 if (!(pg->tpgs & TPGS_MODE_EXPLICIT)) {
737
738 return SCSI_DH_RETRY;
739 }
740 switch (pg->state) {
741 case SCSI_ACCESS_STATE_OPTIMAL:
742 return SCSI_DH_OK;
743 case SCSI_ACCESS_STATE_ACTIVE:
744 if ((pg->flags & ALUA_OPTIMIZE_STPG) &&
745 !pg->pref &&
746 (pg->tpgs & TPGS_MODE_IMPLICIT))
747 return SCSI_DH_OK;
748 break;
749 case SCSI_ACCESS_STATE_STANDBY:
750 case SCSI_ACCESS_STATE_UNAVAILABLE:
751 break;
752 case SCSI_ACCESS_STATE_OFFLINE:
753 return SCSI_DH_IO;
754 case SCSI_ACCESS_STATE_TRANSITIONING:
755 break;
756 default:
757 sdev_printk(KERN_INFO, sdev,
758 "%s: stpg failed, unhandled TPGS state %d",
759 ALUA_DH_NAME, pg->state);
760 return SCSI_DH_NOSYS;
761 }
762 retval = submit_stpg(sdev, pg->group_id, &sense_hdr);
763
764 if (retval) {
765 if (!scsi_sense_valid(&sense_hdr)) {
766 sdev_printk(KERN_INFO, sdev,
767 "%s: stpg failed, result %d",
768 ALUA_DH_NAME, retval);
769 if (driver_byte(retval) == DRIVER_ERROR)
770 return SCSI_DH_DEV_TEMP_BUSY;
771 } else {
772 sdev_printk(KERN_INFO, sdev, "%s: stpg failed\n",
773 ALUA_DH_NAME);
774 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
775 }
776 }
777
778 return SCSI_DH_RETRY;
779}
780
781static void alua_rtpg_work(struct work_struct *work)
782{
783 struct alua_port_group *pg =
784 container_of(work, struct alua_port_group, rtpg_work.work);
785 struct scsi_device *sdev;
786 LIST_HEAD(qdata_list);
787 int err = SCSI_DH_OK;
788 struct alua_queue_data *qdata, *tmp;
789 unsigned long flags;
790
791 spin_lock_irqsave(&pg->lock, flags);
792 sdev = pg->rtpg_sdev;
793 if (!sdev) {
794 WARN_ON(pg->flags & ALUA_PG_RUN_RTPG);
795 WARN_ON(pg->flags & ALUA_PG_RUN_STPG);
796 spin_unlock_irqrestore(&pg->lock, flags);
797 kref_put(&pg->kref, release_port_group);
798 return;
799 }
800 pg->flags |= ALUA_PG_RUNNING;
801 if (pg->flags & ALUA_PG_RUN_RTPG) {
802 int state = pg->state;
803
804 pg->flags &= ~ALUA_PG_RUN_RTPG;
805 spin_unlock_irqrestore(&pg->lock, flags);
806 if (state == SCSI_ACCESS_STATE_TRANSITIONING) {
807 if (alua_tur(sdev) == SCSI_DH_RETRY) {
808 spin_lock_irqsave(&pg->lock, flags);
809 pg->flags &= ~ALUA_PG_RUNNING;
810 pg->flags |= ALUA_PG_RUN_RTPG;
811 if (!pg->interval)
812 pg->interval = ALUA_RTPG_RETRY_DELAY;
813 spin_unlock_irqrestore(&pg->lock, flags);
814 queue_delayed_work(kaluad_wq, &pg->rtpg_work,
815 pg->interval * HZ);
816 return;
817 }
818
819 }
820 err = alua_rtpg(sdev, pg);
821 spin_lock_irqsave(&pg->lock, flags);
822 if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) {
823 pg->flags &= ~ALUA_PG_RUNNING;
824 if (!pg->interval && !(pg->flags & ALUA_PG_RUN_RTPG))
825 pg->interval = ALUA_RTPG_RETRY_DELAY;
826 pg->flags |= ALUA_PG_RUN_RTPG;
827 spin_unlock_irqrestore(&pg->lock, flags);
828 queue_delayed_work(kaluad_wq, &pg->rtpg_work,
829 pg->interval * HZ);
830 return;
831 }
832 if (err != SCSI_DH_OK)
833 pg->flags &= ~ALUA_PG_RUN_STPG;
834 }
835 if (pg->flags & ALUA_PG_RUN_STPG) {
836 pg->flags &= ~ALUA_PG_RUN_STPG;
837 spin_unlock_irqrestore(&pg->lock, flags);
838 err = alua_stpg(sdev, pg);
839 spin_lock_irqsave(&pg->lock, flags);
840 if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) {
841 pg->flags |= ALUA_PG_RUN_RTPG;
842 pg->interval = 0;
843 pg->flags &= ~ALUA_PG_RUNNING;
844 spin_unlock_irqrestore(&pg->lock, flags);
845 queue_delayed_work(kaluad_wq, &pg->rtpg_work,
846 pg->interval * HZ);
847 return;
848 }
849 }
850
851 list_splice_init(&pg->rtpg_list, &qdata_list);
852 pg->rtpg_sdev = NULL;
853 spin_unlock_irqrestore(&pg->lock, flags);
854
855 list_for_each_entry_safe(qdata, tmp, &qdata_list, entry) {
856 list_del(&qdata->entry);
857 if (qdata->callback_fn)
858 qdata->callback_fn(qdata->callback_data, err);
859 kfree(qdata);
860 }
861 spin_lock_irqsave(&pg->lock, flags);
862 pg->flags &= ~ALUA_PG_RUNNING;
863 spin_unlock_irqrestore(&pg->lock, flags);
864 scsi_device_put(sdev);
865 kref_put(&pg->kref, release_port_group);
866}
867
868
869
870
871
872
873
874
875
876
877
878
879static bool alua_rtpg_queue(struct alua_port_group *pg,
880 struct scsi_device *sdev,
881 struct alua_queue_data *qdata, bool force)
882{
883 int start_queue = 0;
884 unsigned long flags;
885 if (WARN_ON_ONCE(!pg) || scsi_device_get(sdev))
886 return false;
887
888 spin_lock_irqsave(&pg->lock, flags);
889 if (qdata) {
890 list_add_tail(&qdata->entry, &pg->rtpg_list);
891 pg->flags |= ALUA_PG_RUN_STPG;
892 force = true;
893 }
894 if (pg->rtpg_sdev == NULL) {
895 pg->interval = 0;
896 pg->flags |= ALUA_PG_RUN_RTPG;
897 kref_get(&pg->kref);
898 pg->rtpg_sdev = sdev;
899 start_queue = 1;
900 } else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force) {
901 pg->flags |= ALUA_PG_RUN_RTPG;
902
903 if (!(pg->flags & ALUA_PG_RUNNING)) {
904 kref_get(&pg->kref);
905 start_queue = 1;
906 }
907 }
908
909 spin_unlock_irqrestore(&pg->lock, flags);
910
911 if (start_queue) {
912 if (queue_delayed_work(kaluad_wq, &pg->rtpg_work,
913 msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS)))
914 sdev = NULL;
915 else
916 kref_put(&pg->kref, release_port_group);
917 }
918 if (sdev)
919 scsi_device_put(sdev);
920
921 return true;
922}
923
924
925
926
927
928
929
930
931static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
932{
933 int err = SCSI_DH_DEV_UNSUPP, tpgs;
934
935 mutex_lock(&h->init_mutex);
936 tpgs = alua_check_tpgs(sdev);
937 if (tpgs != TPGS_MODE_NONE)
938 err = alua_check_vpd(sdev, h, tpgs);
939 h->init_error = err;
940 mutex_unlock(&h->init_mutex);
941 return err;
942}
943
944
945
946
947
948
949
950
951
952static int alua_set_params(struct scsi_device *sdev, const char *params)
953{
954 struct alua_dh_data *h = sdev->handler_data;
955 struct alua_port_group *pg = NULL;
956 unsigned int optimize = 0, argc;
957 const char *p = params;
958 int result = SCSI_DH_OK;
959 unsigned long flags;
960
961 if ((sscanf(params, "%u", &argc) != 1) || (argc != 1))
962 return -EINVAL;
963
964 while (*p++)
965 ;
966 if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1))
967 return -EINVAL;
968
969 rcu_read_lock();
970 pg = rcu_dereference(h->pg);
971 if (!pg) {
972 rcu_read_unlock();
973 return -ENXIO;
974 }
975 spin_lock_irqsave(&pg->lock, flags);
976 if (optimize)
977 pg->flags |= ALUA_OPTIMIZE_STPG;
978 else
979 pg->flags &= ~ALUA_OPTIMIZE_STPG;
980 spin_unlock_irqrestore(&pg->lock, flags);
981 rcu_read_unlock();
982
983 return result;
984}
985
986
987
988
989
990
991
992
993
994
995
996static int alua_activate(struct scsi_device *sdev,
997 activate_complete fn, void *data)
998{
999 struct alua_dh_data *h = sdev->handler_data;
1000 int err = SCSI_DH_OK;
1001 struct alua_queue_data *qdata;
1002 struct alua_port_group *pg;
1003
1004 qdata = kzalloc(sizeof(*qdata), GFP_KERNEL);
1005 if (!qdata) {
1006 err = SCSI_DH_RES_TEMP_UNAVAIL;
1007 goto out;
1008 }
1009 qdata->callback_fn = fn;
1010 qdata->callback_data = data;
1011
1012 mutex_lock(&h->init_mutex);
1013 rcu_read_lock();
1014 pg = rcu_dereference(h->pg);
1015 if (!pg || !kref_get_unless_zero(&pg->kref)) {
1016 rcu_read_unlock();
1017 kfree(qdata);
1018 err = h->init_error;
1019 mutex_unlock(&h->init_mutex);
1020 goto out;
1021 }
1022 rcu_read_unlock();
1023 mutex_unlock(&h->init_mutex);
1024
1025 if (alua_rtpg_queue(pg, sdev, qdata, true))
1026 fn = NULL;
1027 else
1028 err = SCSI_DH_DEV_OFFLINED;
1029 kref_put(&pg->kref, release_port_group);
1030out:
1031 if (fn)
1032 fn(data, err);
1033 return 0;
1034}
1035
1036
1037
1038
1039
1040
1041
1042static void alua_check(struct scsi_device *sdev, bool force)
1043{
1044 struct alua_dh_data *h = sdev->handler_data;
1045 struct alua_port_group *pg;
1046
1047 rcu_read_lock();
1048 pg = rcu_dereference(h->pg);
1049 if (!pg || !kref_get_unless_zero(&pg->kref)) {
1050 rcu_read_unlock();
1051 return;
1052 }
1053 rcu_read_unlock();
1054
1055 alua_rtpg_queue(pg, sdev, NULL, force);
1056 kref_put(&pg->kref, release_port_group);
1057}
1058
1059
1060
1061
1062
1063
1064
1065static blk_status_t alua_prep_fn(struct scsi_device *sdev, struct request *req)
1066{
1067 struct alua_dh_data *h = sdev->handler_data;
1068 struct alua_port_group *pg;
1069 unsigned char state = SCSI_ACCESS_STATE_OPTIMAL;
1070
1071 rcu_read_lock();
1072 pg = rcu_dereference(h->pg);
1073 if (pg)
1074 state = pg->state;
1075 rcu_read_unlock();
1076
1077 switch (state) {
1078 case SCSI_ACCESS_STATE_OPTIMAL:
1079 case SCSI_ACCESS_STATE_ACTIVE:
1080 case SCSI_ACCESS_STATE_LBA:
1081 return BLK_STS_OK;
1082 case SCSI_ACCESS_STATE_TRANSITIONING:
1083 return BLK_STS_RESOURCE;
1084 default:
1085 req->rq_flags |= RQF_QUIET;
1086 return BLK_STS_IOERR;
1087 }
1088}
1089
1090static void alua_rescan(struct scsi_device *sdev)
1091{
1092 struct alua_dh_data *h = sdev->handler_data;
1093
1094 alua_initialize(sdev, h);
1095}
1096
1097
1098
1099
1100
1101static int alua_bus_attach(struct scsi_device *sdev)
1102{
1103 struct alua_dh_data *h;
1104 int err;
1105
1106 h = kzalloc(sizeof(*h) , GFP_KERNEL);
1107 if (!h)
1108 return SCSI_DH_NOMEM;
1109 spin_lock_init(&h->pg_lock);
1110 rcu_assign_pointer(h->pg, NULL);
1111 h->init_error = SCSI_DH_OK;
1112 h->sdev = sdev;
1113 INIT_LIST_HEAD(&h->node);
1114
1115 mutex_init(&h->init_mutex);
1116 err = alua_initialize(sdev, h);
1117 if (err != SCSI_DH_OK && err != SCSI_DH_DEV_OFFLINED)
1118 goto failed;
1119
1120 sdev->handler_data = h;
1121 return SCSI_DH_OK;
1122failed:
1123 kfree(h);
1124 return err;
1125}
1126
1127
1128
1129
1130
1131static void alua_bus_detach(struct scsi_device *sdev)
1132{
1133 struct alua_dh_data *h = sdev->handler_data;
1134 struct alua_port_group *pg;
1135
1136 spin_lock(&h->pg_lock);
1137 pg = rcu_dereference_protected(h->pg, lockdep_is_held(&h->pg_lock));
1138 rcu_assign_pointer(h->pg, NULL);
1139 h->sdev = NULL;
1140 spin_unlock(&h->pg_lock);
1141 if (pg) {
1142 spin_lock_irq(&pg->lock);
1143 list_del_rcu(&h->node);
1144 spin_unlock_irq(&pg->lock);
1145 kref_put(&pg->kref, release_port_group);
1146 }
1147 sdev->handler_data = NULL;
1148 kfree(h);
1149}
1150
1151static struct scsi_device_handler alua_dh = {
1152 .name = ALUA_DH_NAME,
1153 .module = THIS_MODULE,
1154 .attach = alua_bus_attach,
1155 .detach = alua_bus_detach,
1156 .prep_fn = alua_prep_fn,
1157 .check_sense = alua_check_sense,
1158 .activate = alua_activate,
1159 .rescan = alua_rescan,
1160 .set_params = alua_set_params,
1161};
1162
1163static int __init alua_init(void)
1164{
1165 int r;
1166
1167 kaluad_wq = alloc_workqueue("kaluad", WQ_MEM_RECLAIM, 0);
1168 if (!kaluad_wq)
1169 return -ENOMEM;
1170
1171 r = scsi_register_device_handler(&alua_dh);
1172 if (r != 0) {
1173 printk(KERN_ERR "%s: Failed to register scsi device handler",
1174 ALUA_DH_NAME);
1175 destroy_workqueue(kaluad_wq);
1176 }
1177 return r;
1178}
1179
1180static void __exit alua_exit(void)
1181{
1182 scsi_unregister_device_handler(&alua_dh);
1183 destroy_workqueue(kaluad_wq);
1184}
1185
1186module_init(alua_init);
1187module_exit(alua_exit);
1188
1189MODULE_DESCRIPTION("DM Multipath ALUA support");
1190MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
1191MODULE_LICENSE("GPL");
1192MODULE_VERSION(ALUA_DH_VER);
1193