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1/*
2 * Generic SCSI-3 ALUA SCSI Device Handler
3 *
4 * Copyright (C) 2007-2010 Hannes Reinecke, SUSE Linux Products GmbH.
5 * All rights reserved.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20 *
21 */
22#include <linux/slab.h>
23#include <linux/delay.h>
24#include <scsi/scsi.h>
25#include <scsi/scsi_eh.h>
26#include <scsi/scsi_dh.h>
27
28#define ALUA_DH_NAME "alua"
29#define ALUA_DH_VER "1.3"
30
31#define TPGS_STATE_OPTIMIZED 0x0
32#define TPGS_STATE_NONOPTIMIZED 0x1
33#define TPGS_STATE_STANDBY 0x2
34#define TPGS_STATE_UNAVAILABLE 0x3
35#define TPGS_STATE_LBA_DEPENDENT 0x4
36#define TPGS_STATE_OFFLINE 0xe
37#define TPGS_STATE_TRANSITIONING 0xf
38
39#define TPGS_SUPPORT_NONE 0x00
40#define TPGS_SUPPORT_OPTIMIZED 0x01
41#define TPGS_SUPPORT_NONOPTIMIZED 0x02
42#define TPGS_SUPPORT_STANDBY 0x04
43#define TPGS_SUPPORT_UNAVAILABLE 0x08
44#define TPGS_SUPPORT_LBA_DEPENDENT 0x10
45#define TPGS_SUPPORT_OFFLINE 0x40
46#define TPGS_SUPPORT_TRANSITION 0x80
47
48#define TPGS_MODE_UNINITIALIZED -1
49#define TPGS_MODE_NONE 0x0
50#define TPGS_MODE_IMPLICIT 0x1
51#define TPGS_MODE_EXPLICIT 0x2
52
53#define ALUA_INQUIRY_SIZE 36
54#define ALUA_FAILOVER_TIMEOUT (60 * HZ)
55#define ALUA_FAILOVER_RETRIES 5
56
57struct alua_dh_data {
58 int group_id;
59 int rel_port;
60 int tpgs;
61 int state;
62 unsigned char inq[ALUA_INQUIRY_SIZE];
63 unsigned char *buff;
64 int bufflen;
65 unsigned char sense[SCSI_SENSE_BUFFERSIZE];
66 int senselen;
67 struct scsi_device *sdev;
68 activate_complete callback_fn;
69 void *callback_data;
70};
71
72#define ALUA_POLICY_SWITCH_CURRENT 0
73#define ALUA_POLICY_SWITCH_ALL 1
74
75static char print_alua_state(int);
76static int alua_check_sense(struct scsi_device *, struct scsi_sense_hdr *);
77
78static inline struct alua_dh_data *get_alua_data(struct scsi_device *sdev)
79{
80 struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
81 BUG_ON(scsi_dh_data == NULL);
82 return ((struct alua_dh_data *) scsi_dh_data->buf);
83}
84
85static int realloc_buffer(struct alua_dh_data *h, unsigned len)
86{
87 if (h->buff && h->buff != h->inq)
88 kfree(h->buff);
89
90 h->buff = kmalloc(len, GFP_NOIO);
91 if (!h->buff) {
92 h->buff = h->inq;
93 h->bufflen = ALUA_INQUIRY_SIZE;
94 return 1;
95 }
96 h->bufflen = len;
97 return 0;
98}
99
100static struct request *get_alua_req(struct scsi_device *sdev,
101 void *buffer, unsigned buflen, int rw)
102{
103 struct request *rq;
104 struct request_queue *q = sdev->request_queue;
105
106 rq = blk_get_request(q, rw, GFP_NOIO);
107
108 if (!rq) {
109 sdev_printk(KERN_INFO, sdev,
110 "%s: blk_get_request failed\n", __func__);
111 return NULL;
112 }
113
114 if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) {
115 blk_put_request(rq);
116 sdev_printk(KERN_INFO, sdev,
117 "%s: blk_rq_map_kern failed\n", __func__);
118 return NULL;
119 }
120
121 rq->cmd_type = REQ_TYPE_BLOCK_PC;
122 rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
123 REQ_FAILFAST_DRIVER;
124 rq->retries = ALUA_FAILOVER_RETRIES;
125 rq->timeout = ALUA_FAILOVER_TIMEOUT;
126
127 return rq;
128}
129
130/*
131 * submit_std_inquiry - Issue a standard INQUIRY command
132 * @sdev: sdev the command should be send to
133 */
134static int submit_std_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
135{
136 struct request *rq;
137 int err = SCSI_DH_RES_TEMP_UNAVAIL;
138
139 rq = get_alua_req(sdev, h->inq, ALUA_INQUIRY_SIZE, READ);
140 if (!rq)
141 goto done;
142
143 /* Prepare the command. */
144 rq->cmd[0] = INQUIRY;
145 rq->cmd[1] = 0;
146 rq->cmd[2] = 0;
147 rq->cmd[4] = ALUA_INQUIRY_SIZE;
148 rq->cmd_len = COMMAND_SIZE(INQUIRY);
149
150 rq->sense = h->sense;
151 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
152 rq->sense_len = h->senselen = 0;
153
154 err = blk_execute_rq(rq->q, NULL, rq, 1);
155 if (err == -EIO) {
156 sdev_printk(KERN_INFO, sdev,
157 "%s: std inquiry failed with %x\n",
158 ALUA_DH_NAME, rq->errors);
159 h->senselen = rq->sense_len;
160 err = SCSI_DH_IO;
161 }
162 blk_put_request(rq);
163done:
164 return err;
165}
166
167/*
168 * submit_vpd_inquiry - Issue an INQUIRY VPD page 0x83 command
169 * @sdev: sdev the command should be sent to
170 */
171static int submit_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
172{
173 struct request *rq;
174 int err = SCSI_DH_RES_TEMP_UNAVAIL;
175
176 rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
177 if (!rq)
178 goto done;
179
180 /* Prepare the command. */
181 rq->cmd[0] = INQUIRY;
182 rq->cmd[1] = 1;
183 rq->cmd[2] = 0x83;
184 rq->cmd[4] = h->bufflen;
185 rq->cmd_len = COMMAND_SIZE(INQUIRY);
186
187 rq->sense = h->sense;
188 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
189 rq->sense_len = h->senselen = 0;
190
191 err = blk_execute_rq(rq->q, NULL, rq, 1);
192 if (err == -EIO) {
193 sdev_printk(KERN_INFO, sdev,
194 "%s: evpd inquiry failed with %x\n",
195 ALUA_DH_NAME, rq->errors);
196 h->senselen = rq->sense_len;
197 err = SCSI_DH_IO;
198 }
199 blk_put_request(rq);
200done:
201 return err;
202}
203
204/*
205 * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
206 * @sdev: sdev the command should be sent to
207 */
208static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
209{
210 struct request *rq;
211 int err = SCSI_DH_RES_TEMP_UNAVAIL;
212
213 rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
214 if (!rq)
215 goto done;
216
217 /* Prepare the command. */
218 rq->cmd[0] = MAINTENANCE_IN;
219 rq->cmd[1] = MI_REPORT_TARGET_PGS;
220 rq->cmd[6] = (h->bufflen >> 24) & 0xff;
221 rq->cmd[7] = (h->bufflen >> 16) & 0xff;
222 rq->cmd[8] = (h->bufflen >> 8) & 0xff;
223 rq->cmd[9] = h->bufflen & 0xff;
224 rq->cmd_len = COMMAND_SIZE(MAINTENANCE_IN);
225
226 rq->sense = h->sense;
227 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
228 rq->sense_len = h->senselen = 0;
229
230 err = blk_execute_rq(rq->q, NULL, rq, 1);
231 if (err == -EIO) {
232 sdev_printk(KERN_INFO, sdev,
233 "%s: rtpg failed with %x\n",
234 ALUA_DH_NAME, rq->errors);
235 h->senselen = rq->sense_len;
236 err = SCSI_DH_IO;
237 }
238 blk_put_request(rq);
239done:
240 return err;
241}
242
243/*
244 * alua_stpg - Evaluate SET TARGET GROUP STATES
245 * @sdev: the device to be evaluated
246 * @state: the new target group state
247 *
248 * Send a SET TARGET GROUP STATES command to the device.
249 * We only have to test here if we should resubmit the command;
250 * any other error is assumed as a failure.
251 */
252static void stpg_endio(struct request *req, int error)
253{
254 struct alua_dh_data *h = req->end_io_data;
255 struct scsi_sense_hdr sense_hdr;
256 unsigned err = SCSI_DH_OK;
257
258 if (error || host_byte(req->errors) != DID_OK ||
259 msg_byte(req->errors) != COMMAND_COMPLETE) {
260 err = SCSI_DH_IO;
261 goto done;
262 }
263
264 if (h->senselen > 0) {
265 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
266 &sense_hdr);
267 if (!err) {
268 err = SCSI_DH_IO;
269 goto done;
270 }
271 err = alua_check_sense(h->sdev, &sense_hdr);
272 if (err == ADD_TO_MLQUEUE) {
273 err = SCSI_DH_RETRY;
274 goto done;
275 }
276 sdev_printk(KERN_INFO, h->sdev,
277 "%s: stpg sense code: %02x/%02x/%02x\n",
278 ALUA_DH_NAME, sense_hdr.sense_key,
279 sense_hdr.asc, sense_hdr.ascq);
280 err = SCSI_DH_IO;
281 }
282 if (err == SCSI_DH_OK) {
283 h->state = TPGS_STATE_OPTIMIZED;
284 sdev_printk(KERN_INFO, h->sdev,
285 "%s: port group %02x switched to state %c\n",
286 ALUA_DH_NAME, h->group_id,
287 print_alua_state(h->state));
288 }
289done:
290 req->end_io_data = NULL;
291 __blk_put_request(req->q, req);
292 if (h->callback_fn) {
293 h->callback_fn(h->callback_data, err);
294 h->callback_fn = h->callback_data = NULL;
295 }
296 return;
297}
298
299/*
300 * submit_stpg - Issue a SET TARGET GROUP STATES command
301 *
302 * Currently we're only setting the current target port group state
303 * to 'active/optimized' and let the array firmware figure out
304 * the states of the remaining groups.
305 */
306static unsigned submit_stpg(struct alua_dh_data *h)
307{
308 struct request *rq;
309 int stpg_len = 8;
310 struct scsi_device *sdev = h->sdev;
311
312 /* Prepare the data buffer */
313 memset(h->buff, 0, stpg_len);
314 h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f;
315 h->buff[6] = (h->group_id >> 8) & 0xff;
316 h->buff[7] = h->group_id & 0xff;
317
318 rq = get_alua_req(sdev, h->buff, stpg_len, WRITE);
319 if (!rq)
320 return SCSI_DH_RES_TEMP_UNAVAIL;
321
322 /* Prepare the command. */
323 rq->cmd[0] = MAINTENANCE_OUT;
324 rq->cmd[1] = MO_SET_TARGET_PGS;
325 rq->cmd[6] = (stpg_len >> 24) & 0xff;
326 rq->cmd[7] = (stpg_len >> 16) & 0xff;
327 rq->cmd[8] = (stpg_len >> 8) & 0xff;
328 rq->cmd[9] = stpg_len & 0xff;
329 rq->cmd_len = COMMAND_SIZE(MAINTENANCE_OUT);
330
331 rq->sense = h->sense;
332 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
333 rq->sense_len = h->senselen = 0;
334 rq->end_io_data = h;
335
336 blk_execute_rq_nowait(rq->q, NULL, rq, 1, stpg_endio);
337 return SCSI_DH_OK;
338}
339
340/*
341 * alua_std_inquiry - Evaluate standard INQUIRY command
342 * @sdev: device to be checked
343 *
344 * Just extract the TPGS setting to find out if ALUA
345 * is supported.
346 */
347static int alua_std_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
348{
349 int err;
350
351 err = submit_std_inquiry(sdev, h);
352
353 if (err != SCSI_DH_OK)
354 return err;
355
356 /* Check TPGS setting */
357 h->tpgs = (h->inq[5] >> 4) & 0x3;
358 switch (h->tpgs) {
359 case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
360 sdev_printk(KERN_INFO, sdev,
361 "%s: supports implicit and explicit TPGS\n",
362 ALUA_DH_NAME);
363 break;
364 case TPGS_MODE_EXPLICIT:
365 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n",
366 ALUA_DH_NAME);
367 break;
368 case TPGS_MODE_IMPLICIT:
369 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n",
370 ALUA_DH_NAME);
371 break;
372 default:
373 h->tpgs = TPGS_MODE_NONE;
374 sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
375 ALUA_DH_NAME);
376 err = SCSI_DH_DEV_UNSUPP;
377 break;
378 }
379
380 return err;
381}
382
383/*
384 * alua_vpd_inquiry - Evaluate INQUIRY vpd page 0x83
385 * @sdev: device to be checked
386 *
387 * Extract the relative target port and the target port group
388 * descriptor from the list of identificators.
389 */
390static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
391{
392 int len;
393 unsigned err;
394 unsigned char *d;
395
396 retry:
397 err = submit_vpd_inquiry(sdev, h);
398
399 if (err != SCSI_DH_OK)
400 return err;
401
402 /* Check if vpd page exceeds initial buffer */
403 len = (h->buff[2] << 8) + h->buff[3] + 4;
404 if (len > h->bufflen) {
405 /* Resubmit with the correct length */
406 if (realloc_buffer(h, len)) {
407 sdev_printk(KERN_WARNING, sdev,
408 "%s: kmalloc buffer failed\n",
409 ALUA_DH_NAME);
410 /* Temporary failure, bypass */
411 return SCSI_DH_DEV_TEMP_BUSY;
412 }
413 goto retry;
414 }
415
416 /*
417 * Now look for the correct descriptor.
418 */
419 d = h->buff + 4;
420 while (d < h->buff + len) {
421 switch (d[1] & 0xf) {
422 case 0x4:
423 /* Relative target port */
424 h->rel_port = (d[6] << 8) + d[7];
425 break;
426 case 0x5:
427 /* Target port group */
428 h->group_id = (d[6] << 8) + d[7];
429 break;
430 default:
431 break;
432 }
433 d += d[3] + 4;
434 }
435
436 if (h->group_id == -1) {
437 /*
438 * Internal error; TPGS supported but required
439 * VPD identification descriptors not present.
440 * Disable ALUA support
441 */
442 sdev_printk(KERN_INFO, sdev,
443 "%s: No target port descriptors found\n",
444 ALUA_DH_NAME);
445 h->state = TPGS_STATE_OPTIMIZED;
446 h->tpgs = TPGS_MODE_NONE;
447 err = SCSI_DH_DEV_UNSUPP;
448 } else {
449 sdev_printk(KERN_INFO, sdev,
450 "%s: port group %02x rel port %02x\n",
451 ALUA_DH_NAME, h->group_id, h->rel_port);
452 }
453
454 return err;
455}
456
457static char print_alua_state(int state)
458{
459 switch (state) {
460 case TPGS_STATE_OPTIMIZED:
461 return 'A';
462 case TPGS_STATE_NONOPTIMIZED:
463 return 'N';
464 case TPGS_STATE_STANDBY:
465 return 'S';
466 case TPGS_STATE_UNAVAILABLE:
467 return 'U';
468 case TPGS_STATE_LBA_DEPENDENT:
469 return 'L';
470 case TPGS_STATE_OFFLINE:
471 return 'O';
472 case TPGS_STATE_TRANSITIONING:
473 return 'T';
474 default:
475 return 'X';
476 }
477}
478
479static int alua_check_sense(struct scsi_device *sdev,
480 struct scsi_sense_hdr *sense_hdr)
481{
482 switch (sense_hdr->sense_key) {
483 case NOT_READY:
484 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a)
485 /*
486 * LUN Not Accessible - ALUA state transition
487 */
488 return ADD_TO_MLQUEUE;
489 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0b)
490 /*
491 * LUN Not Accessible -- Target port in standby state
492 */
493 return SUCCESS;
494 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0c)
495 /*
496 * LUN Not Accessible -- Target port in unavailable state
497 */
498 return SUCCESS;
499 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x12)
500 /*
501 * LUN Not Ready -- Offline
502 */
503 return SUCCESS;
504 break;
505 case UNIT_ATTENTION:
506 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
507 /*
508 * Power On, Reset, or Bus Device Reset, just retry.
509 */
510 return ADD_TO_MLQUEUE;
511 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
512 /*
513 * ALUA state changed
514 */
515 return ADD_TO_MLQUEUE;
516 }
517 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
518 /*
519 * Implicit ALUA state transition failed
520 */
521 return ADD_TO_MLQUEUE;
522 }
523 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e) {
524 /*
525 * REPORTED_LUNS_DATA_HAS_CHANGED is reported
526 * when switching controllers on targets like
527 * Intel Multi-Flex. We can just retry.
528 */
529 return ADD_TO_MLQUEUE;
530 }
531
532 break;
533 }
534
535 return SCSI_RETURN_NOT_HANDLED;
536}
537
538/*
539 * alua_rtpg - Evaluate REPORT TARGET GROUP STATES
540 * @sdev: the device to be evaluated.
541 *
542 * Evaluate the Target Port Group State.
543 * Returns SCSI_DH_DEV_OFFLINED if the path is
544 * found to be unusable.
545 */
546static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
547{
548 struct scsi_sense_hdr sense_hdr;
549 int len, k, off, valid_states = 0;
550 char *ucp;
551 unsigned err;
552 unsigned long expiry, interval = 10;
553
554 expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT);
555 retry:
556 err = submit_rtpg(sdev, h);
557
558 if (err == SCSI_DH_IO && h->senselen > 0) {
559 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
560 &sense_hdr);
561 if (!err)
562 return SCSI_DH_IO;
563
564 err = alua_check_sense(sdev, &sense_hdr);
565 if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry))
566 goto retry;
567 sdev_printk(KERN_INFO, sdev,
568 "%s: rtpg sense code %02x/%02x/%02x\n",
569 ALUA_DH_NAME, sense_hdr.sense_key,
570 sense_hdr.asc, sense_hdr.ascq);
571 err = SCSI_DH_IO;
572 }
573 if (err != SCSI_DH_OK)
574 return err;
575
576 len = (h->buff[0] << 24) + (h->buff[1] << 16) +
577 (h->buff[2] << 8) + h->buff[3] + 4;
578
579 if (len > h->bufflen) {
580 /* Resubmit with the correct length */
581 if (realloc_buffer(h, len)) {
582 sdev_printk(KERN_WARNING, sdev,
583 "%s: kmalloc buffer failed\n",__func__);
584 /* Temporary failure, bypass */
585 return SCSI_DH_DEV_TEMP_BUSY;
586 }
587 goto retry;
588 }
589
590 for (k = 4, ucp = h->buff + 4; k < len; k += off, ucp += off) {
591 if (h->group_id == (ucp[2] << 8) + ucp[3]) {
592 h->state = ucp[0] & 0x0f;
593 valid_states = ucp[1];
594 }
595 off = 8 + (ucp[7] * 4);
596 }
597
598 sdev_printk(KERN_INFO, sdev,
599 "%s: port group %02x state %c supports %c%c%c%c%c%c%c\n",
600 ALUA_DH_NAME, h->group_id, print_alua_state(h->state),
601 valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
602 valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
603 valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
604 valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
605 valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
606 valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
607 valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
608
609 switch (h->state) {
610 case TPGS_STATE_TRANSITIONING:
611 if (time_before(jiffies, expiry)) {
612 /* State transition, retry */
613 interval *= 10;
614 msleep(interval);
615 goto retry;
616 }
617 /* Transitioning time exceeded, set port to standby */
618 err = SCSI_DH_RETRY;
619 h->state = TPGS_STATE_STANDBY;
620 break;
621 case TPGS_STATE_OFFLINE:
622 case TPGS_STATE_UNAVAILABLE:
623 /* Path unusable for unavailable/offline */
624 err = SCSI_DH_DEV_OFFLINED;
625 break;
626 default:
627 /* Useable path if active */
628 err = SCSI_DH_OK;
629 break;
630 }
631 return err;
632}
633
634/*
635 * alua_initialize - Initialize ALUA state
636 * @sdev: the device to be initialized
637 *
638 * For the prep_fn to work correctly we have
639 * to initialize the ALUA state for the device.
640 */
641static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
642{
643 int err;
644
645 err = alua_std_inquiry(sdev, h);
646 if (err != SCSI_DH_OK)
647 goto out;
648
649 err = alua_vpd_inquiry(sdev, h);
650 if (err != SCSI_DH_OK)
651 goto out;
652
653 err = alua_rtpg(sdev, h);
654 if (err != SCSI_DH_OK)
655 goto out;
656
657out:
658 return err;
659}
660
661/*
662 * alua_activate - activate a path
663 * @sdev: device on the path to be activated
664 *
665 * We're currently switching the port group to be activated only and
666 * let the array figure out the rest.
667 * There may be other arrays which require us to switch all port groups
668 * based on a certain policy. But until we actually encounter them it
669 * should be okay.
670 */
671static int alua_activate(struct scsi_device *sdev,
672 activate_complete fn, void *data)
673{
674 struct alua_dh_data *h = get_alua_data(sdev);
675 int err = SCSI_DH_OK;
676
677 if (h->group_id != -1) {
678 err = alua_rtpg(sdev, h);
679 if (err != SCSI_DH_OK)
680 goto out;
681 }
682
683 if (h->tpgs & TPGS_MODE_EXPLICIT &&
684 h->state != TPGS_STATE_OPTIMIZED &&
685 h->state != TPGS_STATE_LBA_DEPENDENT) {
686 h->callback_fn = fn;
687 h->callback_data = data;
688 err = submit_stpg(h);
689 if (err == SCSI_DH_OK)
690 return 0;
691 h->callback_fn = h->callback_data = NULL;
692 }
693
694out:
695 if (fn)
696 fn(data, err);
697 return 0;
698}
699
700/*
701 * alua_prep_fn - request callback
702 *
703 * Fail I/O to all paths not in state
704 * active/optimized or active/non-optimized.
705 */
706static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
707{
708 struct alua_dh_data *h = get_alua_data(sdev);
709 int ret = BLKPREP_OK;
710
711 if (h->state == TPGS_STATE_TRANSITIONING)
712 ret = BLKPREP_DEFER;
713 else if (h->state != TPGS_STATE_OPTIMIZED &&
714 h->state != TPGS_STATE_NONOPTIMIZED &&
715 h->state != TPGS_STATE_LBA_DEPENDENT) {
716 ret = BLKPREP_KILL;
717 req->cmd_flags |= REQ_QUIET;
718 }
719 return ret;
720
721}
722
723static const struct scsi_dh_devlist alua_dev_list[] = {
724 {"HP", "MSA VOLUME" },
725 {"HP", "HSV101" },
726 {"HP", "HSV111" },
727 {"HP", "HSV200" },
728 {"HP", "HSV210" },
729 {"HP", "HSV300" },
730 {"IBM", "2107900" },
731 {"IBM", "2145" },
732 {"Pillar", "Axiom" },
733 {"Intel", "Multi-Flex"},
734 {"NETAPP", "LUN"},
735 {"NETAPP", "LUN C-Mode"},
736 {"AIX", "NVDISK"},
737 {"Promise", "VTrak"},
738 {NULL, NULL}
739};
740
741static int alua_bus_attach(struct scsi_device *sdev);
742static void alua_bus_detach(struct scsi_device *sdev);
743
744static struct scsi_device_handler alua_dh = {
745 .name = ALUA_DH_NAME,
746 .module = THIS_MODULE,
747 .devlist = alua_dev_list,
748 .attach = alua_bus_attach,
749 .detach = alua_bus_detach,
750 .prep_fn = alua_prep_fn,
751 .check_sense = alua_check_sense,
752 .activate = alua_activate,
753};
754
755/*
756 * alua_bus_attach - Attach device handler
757 * @sdev: device to be attached to
758 */
759static int alua_bus_attach(struct scsi_device *sdev)
760{
761 struct scsi_dh_data *scsi_dh_data;
762 struct alua_dh_data *h;
763 unsigned long flags;
764 int err = SCSI_DH_OK;
765
766 scsi_dh_data = kzalloc(sizeof(*scsi_dh_data)
767 + sizeof(*h) , GFP_KERNEL);
768 if (!scsi_dh_data) {
769 sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
770 ALUA_DH_NAME);
771 return -ENOMEM;
772 }
773
774 scsi_dh_data->scsi_dh = &alua_dh;
775 h = (struct alua_dh_data *) scsi_dh_data->buf;
776 h->tpgs = TPGS_MODE_UNINITIALIZED;
777 h->state = TPGS_STATE_OPTIMIZED;
778 h->group_id = -1;
779 h->rel_port = -1;
780 h->buff = h->inq;
781 h->bufflen = ALUA_INQUIRY_SIZE;
782 h->sdev = sdev;
783
784 err = alua_initialize(sdev, h);
785 if ((err != SCSI_DH_OK) && (err != SCSI_DH_DEV_OFFLINED))
786 goto failed;
787
788 if (!try_module_get(THIS_MODULE))
789 goto failed;
790
791 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
792 sdev->scsi_dh_data = scsi_dh_data;
793 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
794
795 return 0;
796
797failed:
798 kfree(scsi_dh_data);
799 sdev_printk(KERN_ERR, sdev, "%s: not attached\n", ALUA_DH_NAME);
800 return -EINVAL;
801}
802
803/*
804 * alua_bus_detach - Detach device handler
805 * @sdev: device to be detached from
806 */
807static void alua_bus_detach(struct scsi_device *sdev)
808{
809 struct scsi_dh_data *scsi_dh_data;
810 struct alua_dh_data *h;
811 unsigned long flags;
812
813 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
814 scsi_dh_data = sdev->scsi_dh_data;
815 sdev->scsi_dh_data = NULL;
816 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
817
818 h = (struct alua_dh_data *) scsi_dh_data->buf;
819 if (h->buff && h->inq != h->buff)
820 kfree(h->buff);
821 kfree(scsi_dh_data);
822 module_put(THIS_MODULE);
823 sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", ALUA_DH_NAME);
824}
825
826static int __init alua_init(void)
827{
828 int r;
829
830 r = scsi_register_device_handler(&alua_dh);
831 if (r != 0)
832 printk(KERN_ERR "%s: Failed to register scsi device handler",
833 ALUA_DH_NAME);
834 return r;
835}
836
837static void __exit alua_exit(void)
838{
839 scsi_unregister_device_handler(&alua_dh);
840}
841
842module_init(alua_init);
843module_exit(alua_exit);
844
845MODULE_DESCRIPTION("DM Multipath ALUA support");
846MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
847MODULE_LICENSE("GPL");
848MODULE_VERSION(ALUA_DH_VER);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Generic SCSI-3 ALUA SCSI Device Handler
4 *
5 * Copyright (C) 2007-2010 Hannes Reinecke, SUSE Linux Products GmbH.
6 * All rights reserved.
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/* device handler flags */
46#define ALUA_OPTIMIZE_STPG 0x01
47#define ALUA_RTPG_EXT_HDR_UNSUPP 0x02
48/* State machine flags */
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; /* used for optimizing STPG */
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 bool disabled;
92};
93
94struct alua_queue_data {
95 struct list_head entry;
96 activate_complete callback_fn;
97 void *callback_data;
98};
99
100#define ALUA_POLICY_SWITCH_CURRENT 0
101#define ALUA_POLICY_SWITCH_ALL 1
102
103static void alua_rtpg_work(struct work_struct *work);
104static bool alua_rtpg_queue(struct alua_port_group *pg,
105 struct scsi_device *sdev,
106 struct alua_queue_data *qdata, bool force);
107static void alua_check(struct scsi_device *sdev, bool force);
108
109static void release_port_group(struct kref *kref)
110{
111 struct alua_port_group *pg;
112
113 pg = container_of(kref, struct alua_port_group, kref);
114 if (pg->rtpg_sdev)
115 flush_delayed_work(&pg->rtpg_work);
116 spin_lock(&port_group_lock);
117 list_del(&pg->node);
118 spin_unlock(&port_group_lock);
119 kfree_rcu(pg, rcu);
120}
121
122/*
123 * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
124 * @sdev: sdev the command should be sent to
125 */
126static int submit_rtpg(struct scsi_device *sdev, unsigned char *buff,
127 int bufflen, struct scsi_sense_hdr *sshdr, int flags)
128{
129 u8 cdb[MAX_COMMAND_SIZE];
130 blk_opf_t req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
131 REQ_FAILFAST_DRIVER;
132
133 /* Prepare the command. */
134 memset(cdb, 0x0, MAX_COMMAND_SIZE);
135 cdb[0] = MAINTENANCE_IN;
136 if (!(flags & ALUA_RTPG_EXT_HDR_UNSUPP))
137 cdb[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT;
138 else
139 cdb[1] = MI_REPORT_TARGET_PGS;
140 put_unaligned_be32(bufflen, &cdb[6]);
141
142 return scsi_execute(sdev, cdb, DMA_FROM_DEVICE, buff, bufflen, NULL,
143 sshdr, ALUA_FAILOVER_TIMEOUT * HZ,
144 ALUA_FAILOVER_RETRIES, req_flags, 0, NULL);
145}
146
147/*
148 * submit_stpg - Issue a SET TARGET PORT GROUP command
149 *
150 * Currently we're only setting the current target port group state
151 * to 'active/optimized' and let the array firmware figure out
152 * the states of the remaining groups.
153 */
154static int submit_stpg(struct scsi_device *sdev, int group_id,
155 struct scsi_sense_hdr *sshdr)
156{
157 u8 cdb[MAX_COMMAND_SIZE];
158 unsigned char stpg_data[8];
159 int stpg_len = 8;
160 blk_opf_t req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
161 REQ_FAILFAST_DRIVER;
162
163 /* Prepare the data buffer */
164 memset(stpg_data, 0, stpg_len);
165 stpg_data[4] = SCSI_ACCESS_STATE_OPTIMAL;
166 put_unaligned_be16(group_id, &stpg_data[6]);
167
168 /* Prepare the command. */
169 memset(cdb, 0x0, MAX_COMMAND_SIZE);
170 cdb[0] = MAINTENANCE_OUT;
171 cdb[1] = MO_SET_TARGET_PGS;
172 put_unaligned_be32(stpg_len, &cdb[6]);
173
174 return scsi_execute(sdev, cdb, DMA_TO_DEVICE, stpg_data, stpg_len, NULL,
175 sshdr, ALUA_FAILOVER_TIMEOUT * HZ,
176 ALUA_FAILOVER_RETRIES, req_flags, 0, NULL);
177}
178
179static struct alua_port_group *alua_find_get_pg(char *id_str, size_t id_size,
180 int group_id)
181{
182 struct alua_port_group *pg;
183
184 if (!id_str || !id_size || !strlen(id_str))
185 return NULL;
186
187 list_for_each_entry(pg, &port_group_list, node) {
188 if (pg->group_id != group_id)
189 continue;
190 if (!pg->device_id_len || pg->device_id_len != id_size)
191 continue;
192 if (strncmp(pg->device_id_str, id_str, id_size))
193 continue;
194 if (!kref_get_unless_zero(&pg->kref))
195 continue;
196 return pg;
197 }
198
199 return NULL;
200}
201
202/*
203 * alua_alloc_pg - Allocate a new port_group structure
204 * @sdev: scsi device
205 * @group_id: port group id
206 * @tpgs: target port group settings
207 *
208 * Allocate a new port_group structure for a given
209 * device.
210 */
211static struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev,
212 int group_id, int tpgs)
213{
214 struct alua_port_group *pg, *tmp_pg;
215
216 pg = kzalloc(sizeof(struct alua_port_group), GFP_KERNEL);
217 if (!pg)
218 return ERR_PTR(-ENOMEM);
219
220 pg->device_id_len = scsi_vpd_lun_id(sdev, pg->device_id_str,
221 sizeof(pg->device_id_str));
222 if (pg->device_id_len <= 0) {
223 /*
224 * TPGS supported but no device identification found.
225 * Generate private device identification.
226 */
227 sdev_printk(KERN_INFO, sdev,
228 "%s: No device descriptors found\n",
229 ALUA_DH_NAME);
230 pg->device_id_str[0] = '\0';
231 pg->device_id_len = 0;
232 }
233 pg->group_id = group_id;
234 pg->tpgs = tpgs;
235 pg->state = SCSI_ACCESS_STATE_OPTIMAL;
236 pg->valid_states = TPGS_SUPPORT_ALL;
237 if (optimize_stpg)
238 pg->flags |= ALUA_OPTIMIZE_STPG;
239 kref_init(&pg->kref);
240 INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work);
241 INIT_LIST_HEAD(&pg->rtpg_list);
242 INIT_LIST_HEAD(&pg->node);
243 INIT_LIST_HEAD(&pg->dh_list);
244 spin_lock_init(&pg->lock);
245
246 spin_lock(&port_group_lock);
247 tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len,
248 group_id);
249 if (tmp_pg) {
250 spin_unlock(&port_group_lock);
251 kfree(pg);
252 return tmp_pg;
253 }
254
255 list_add(&pg->node, &port_group_list);
256 spin_unlock(&port_group_lock);
257
258 return pg;
259}
260
261/*
262 * alua_check_tpgs - Evaluate TPGS setting
263 * @sdev: device to be checked
264 *
265 * Examine the TPGS setting of the sdev to find out if ALUA
266 * is supported.
267 */
268static int alua_check_tpgs(struct scsi_device *sdev)
269{
270 int tpgs = TPGS_MODE_NONE;
271
272 /*
273 * ALUA support for non-disk devices is fraught with
274 * difficulties, so disable it for now.
275 */
276 if (sdev->type != TYPE_DISK) {
277 sdev_printk(KERN_INFO, sdev,
278 "%s: disable for non-disk devices\n",
279 ALUA_DH_NAME);
280 return tpgs;
281 }
282
283 tpgs = scsi_device_tpgs(sdev);
284 switch (tpgs) {
285 case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
286 sdev_printk(KERN_INFO, sdev,
287 "%s: supports implicit and explicit TPGS\n",
288 ALUA_DH_NAME);
289 break;
290 case TPGS_MODE_EXPLICIT:
291 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n",
292 ALUA_DH_NAME);
293 break;
294 case TPGS_MODE_IMPLICIT:
295 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n",
296 ALUA_DH_NAME);
297 break;
298 case TPGS_MODE_NONE:
299 sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
300 ALUA_DH_NAME);
301 break;
302 default:
303 sdev_printk(KERN_INFO, sdev,
304 "%s: unsupported TPGS setting %d\n",
305 ALUA_DH_NAME, tpgs);
306 tpgs = TPGS_MODE_NONE;
307 break;
308 }
309
310 return tpgs;
311}
312
313/*
314 * alua_check_vpd - Evaluate INQUIRY vpd page 0x83
315 * @sdev: device to be checked
316 *
317 * Extract the relative target port and the target port group
318 * descriptor from the list of identificators.
319 */
320static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h,
321 int tpgs)
322{
323 int rel_port = -1, group_id;
324 struct alua_port_group *pg, *old_pg = NULL;
325 bool pg_updated = false;
326 unsigned long flags;
327
328 group_id = scsi_vpd_tpg_id(sdev, &rel_port);
329 if (group_id < 0) {
330 /*
331 * Internal error; TPGS supported but required
332 * VPD identification descriptors not present.
333 * Disable ALUA support
334 */
335 sdev_printk(KERN_INFO, sdev,
336 "%s: No target port descriptors found\n",
337 ALUA_DH_NAME);
338 return SCSI_DH_DEV_UNSUPP;
339 }
340
341 pg = alua_alloc_pg(sdev, group_id, tpgs);
342 if (IS_ERR(pg)) {
343 if (PTR_ERR(pg) == -ENOMEM)
344 return SCSI_DH_NOMEM;
345 return SCSI_DH_DEV_UNSUPP;
346 }
347 if (pg->device_id_len)
348 sdev_printk(KERN_INFO, sdev,
349 "%s: device %s port group %x rel port %x\n",
350 ALUA_DH_NAME, pg->device_id_str,
351 group_id, rel_port);
352 else
353 sdev_printk(KERN_INFO, sdev,
354 "%s: port group %x rel port %x\n",
355 ALUA_DH_NAME, group_id, rel_port);
356
357 kref_get(&pg->kref);
358
359 /* Check for existing port group references */
360 spin_lock(&h->pg_lock);
361 old_pg = rcu_dereference_protected(h->pg, lockdep_is_held(&h->pg_lock));
362 if (old_pg != pg) {
363 /* port group has changed. Update to new port group */
364 if (h->pg) {
365 spin_lock_irqsave(&old_pg->lock, flags);
366 list_del_rcu(&h->node);
367 spin_unlock_irqrestore(&old_pg->lock, flags);
368 }
369 rcu_assign_pointer(h->pg, pg);
370 pg_updated = true;
371 }
372
373 spin_lock_irqsave(&pg->lock, flags);
374 if (pg_updated)
375 list_add_rcu(&h->node, &pg->dh_list);
376 spin_unlock_irqrestore(&pg->lock, flags);
377
378 spin_unlock(&h->pg_lock);
379
380 alua_rtpg_queue(pg, sdev, NULL, true);
381 kref_put(&pg->kref, release_port_group);
382
383 if (old_pg)
384 kref_put(&old_pg->kref, release_port_group);
385
386 return SCSI_DH_OK;
387}
388
389static char print_alua_state(unsigned char state)
390{
391 switch (state) {
392 case SCSI_ACCESS_STATE_OPTIMAL:
393 return 'A';
394 case SCSI_ACCESS_STATE_ACTIVE:
395 return 'N';
396 case SCSI_ACCESS_STATE_STANDBY:
397 return 'S';
398 case SCSI_ACCESS_STATE_UNAVAILABLE:
399 return 'U';
400 case SCSI_ACCESS_STATE_LBA:
401 return 'L';
402 case SCSI_ACCESS_STATE_OFFLINE:
403 return 'O';
404 case SCSI_ACCESS_STATE_TRANSITIONING:
405 return 'T';
406 default:
407 return 'X';
408 }
409}
410
411static enum scsi_disposition alua_check_sense(struct scsi_device *sdev,
412 struct scsi_sense_hdr *sense_hdr)
413{
414 struct alua_dh_data *h = sdev->handler_data;
415 struct alua_port_group *pg;
416
417 switch (sense_hdr->sense_key) {
418 case NOT_READY:
419 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) {
420 /*
421 * LUN Not Accessible - ALUA state transition
422 */
423 rcu_read_lock();
424 pg = rcu_dereference(h->pg);
425 if (pg)
426 pg->state = SCSI_ACCESS_STATE_TRANSITIONING;
427 rcu_read_unlock();
428 alua_check(sdev, false);
429 return NEEDS_RETRY;
430 }
431 break;
432 case UNIT_ATTENTION:
433 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) {
434 /*
435 * Power On, Reset, or Bus Device Reset.
436 * Might have obscured a state transition,
437 * so schedule a recheck.
438 */
439 alua_check(sdev, true);
440 return ADD_TO_MLQUEUE;
441 }
442 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x04)
443 /*
444 * Device internal reset
445 */
446 return ADD_TO_MLQUEUE;
447 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01)
448 /*
449 * Mode Parameters Changed
450 */
451 return ADD_TO_MLQUEUE;
452 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
453 /*
454 * ALUA state changed
455 */
456 alua_check(sdev, true);
457 return ADD_TO_MLQUEUE;
458 }
459 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
460 /*
461 * Implicit ALUA state transition failed
462 */
463 alua_check(sdev, true);
464 return ADD_TO_MLQUEUE;
465 }
466 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03)
467 /*
468 * Inquiry data has changed
469 */
470 return ADD_TO_MLQUEUE;
471 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e)
472 /*
473 * REPORTED_LUNS_DATA_HAS_CHANGED is reported
474 * when switching controllers on targets like
475 * Intel Multi-Flex. We can just retry.
476 */
477 return ADD_TO_MLQUEUE;
478 break;
479 }
480
481 return SCSI_RETURN_NOT_HANDLED;
482}
483
484/*
485 * alua_tur - Send a TEST UNIT READY
486 * @sdev: device to which the TEST UNIT READY command should be send
487 *
488 * Send a TEST UNIT READY to @sdev to figure out the device state
489 * Returns SCSI_DH_RETRY if the sense code is NOT READY/ALUA TRANSITIONING,
490 * SCSI_DH_OK if no error occurred, and SCSI_DH_IO otherwise.
491 */
492static int alua_tur(struct scsi_device *sdev)
493{
494 struct scsi_sense_hdr sense_hdr;
495 int retval;
496
497 retval = scsi_test_unit_ready(sdev, ALUA_FAILOVER_TIMEOUT * HZ,
498 ALUA_FAILOVER_RETRIES, &sense_hdr);
499 if (sense_hdr.sense_key == NOT_READY &&
500 sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a)
501 return SCSI_DH_RETRY;
502 else if (retval)
503 return SCSI_DH_IO;
504 else
505 return SCSI_DH_OK;
506}
507
508/*
509 * alua_rtpg - Evaluate REPORT TARGET GROUP STATES
510 * @sdev: the device to be evaluated.
511 *
512 * Evaluate the Target Port Group State.
513 * Returns SCSI_DH_DEV_OFFLINED if the path is
514 * found to be unusable.
515 */
516static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
517{
518 struct scsi_sense_hdr sense_hdr;
519 struct alua_port_group *tmp_pg;
520 int len, k, off, bufflen = ALUA_RTPG_SIZE;
521 int group_id_old, state_old, pref_old, valid_states_old;
522 unsigned char *desc, *buff;
523 unsigned err;
524 int retval;
525 unsigned int tpg_desc_tbl_off;
526 unsigned char orig_transition_tmo;
527 unsigned long flags;
528 bool transitioning_sense = false;
529
530 group_id_old = pg->group_id;
531 state_old = pg->state;
532 pref_old = pg->pref;
533 valid_states_old = pg->valid_states;
534
535 if (!pg->expiry) {
536 unsigned long transition_tmo = ALUA_FAILOVER_TIMEOUT * HZ;
537
538 if (pg->transition_tmo)
539 transition_tmo = pg->transition_tmo * HZ;
540
541 pg->expiry = round_jiffies_up(jiffies + transition_tmo);
542 }
543
544 buff = kzalloc(bufflen, GFP_KERNEL);
545 if (!buff)
546 return SCSI_DH_DEV_TEMP_BUSY;
547
548 retry:
549 err = 0;
550 retval = submit_rtpg(sdev, buff, bufflen, &sense_hdr, pg->flags);
551
552 if (retval) {
553 /*
554 * Some (broken) implementations have a habit of returning
555 * an error during things like firmware update etc.
556 * But if the target only supports active/optimized there's
557 * not much we can do; it's not that we can switch paths
558 * or anything.
559 * So ignore any errors to avoid spurious failures during
560 * path failover.
561 */
562 if ((pg->valid_states & ~TPGS_SUPPORT_OPTIMIZED) == 0) {
563 sdev_printk(KERN_INFO, sdev,
564 "%s: ignoring rtpg result %d\n",
565 ALUA_DH_NAME, retval);
566 kfree(buff);
567 return SCSI_DH_OK;
568 }
569 if (retval < 0 || !scsi_sense_valid(&sense_hdr)) {
570 sdev_printk(KERN_INFO, sdev,
571 "%s: rtpg failed, result %d\n",
572 ALUA_DH_NAME, retval);
573 kfree(buff);
574 if (retval < 0)
575 return SCSI_DH_DEV_TEMP_BUSY;
576 if (host_byte(retval) == DID_NO_CONNECT)
577 return SCSI_DH_RES_TEMP_UNAVAIL;
578 return SCSI_DH_IO;
579 }
580
581 /*
582 * submit_rtpg() has failed on existing arrays
583 * when requesting extended header info, and
584 * the array doesn't support extended headers,
585 * even though it shouldn't according to T10.
586 * The retry without rtpg_ext_hdr_req set
587 * handles this.
588 * Note: some arrays return a sense key of ILLEGAL_REQUEST
589 * with ASC 00h if they don't support the extended header.
590 */
591 if (!(pg->flags & ALUA_RTPG_EXT_HDR_UNSUPP) &&
592 sense_hdr.sense_key == ILLEGAL_REQUEST) {
593 pg->flags |= ALUA_RTPG_EXT_HDR_UNSUPP;
594 goto retry;
595 }
596 /*
597 * If the array returns with 'ALUA state transition'
598 * sense code here it cannot return RTPG data during
599 * transition. So set the state to 'transitioning' directly.
600 */
601 if (sense_hdr.sense_key == NOT_READY &&
602 sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a) {
603 transitioning_sense = true;
604 goto skip_rtpg;
605 }
606 /*
607 * Retry on any other UNIT ATTENTION occurred.
608 */
609 if (sense_hdr.sense_key == UNIT_ATTENTION)
610 err = SCSI_DH_RETRY;
611 if (err == SCSI_DH_RETRY &&
612 pg->expiry != 0 && time_before(jiffies, pg->expiry)) {
613 sdev_printk(KERN_ERR, sdev, "%s: rtpg retry\n",
614 ALUA_DH_NAME);
615 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
616 kfree(buff);
617 return err;
618 }
619 sdev_printk(KERN_ERR, sdev, "%s: rtpg failed\n",
620 ALUA_DH_NAME);
621 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
622 kfree(buff);
623 pg->expiry = 0;
624 return SCSI_DH_IO;
625 }
626
627 len = get_unaligned_be32(&buff[0]) + 4;
628
629 if (len > bufflen) {
630 /* Resubmit with the correct length */
631 kfree(buff);
632 bufflen = len;
633 buff = kmalloc(bufflen, GFP_KERNEL);
634 if (!buff) {
635 sdev_printk(KERN_WARNING, sdev,
636 "%s: kmalloc buffer failed\n",__func__);
637 /* Temporary failure, bypass */
638 pg->expiry = 0;
639 return SCSI_DH_DEV_TEMP_BUSY;
640 }
641 goto retry;
642 }
643
644 orig_transition_tmo = pg->transition_tmo;
645 if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && buff[5] != 0)
646 pg->transition_tmo = buff[5];
647 else
648 pg->transition_tmo = ALUA_FAILOVER_TIMEOUT;
649
650 if (orig_transition_tmo != pg->transition_tmo) {
651 sdev_printk(KERN_INFO, sdev,
652 "%s: transition timeout set to %d seconds\n",
653 ALUA_DH_NAME, pg->transition_tmo);
654 pg->expiry = jiffies + pg->transition_tmo * HZ;
655 }
656
657 if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR)
658 tpg_desc_tbl_off = 8;
659 else
660 tpg_desc_tbl_off = 4;
661
662 for (k = tpg_desc_tbl_off, desc = buff + tpg_desc_tbl_off;
663 k < len;
664 k += off, desc += off) {
665 u16 group_id = get_unaligned_be16(&desc[2]);
666
667 spin_lock_irqsave(&port_group_lock, flags);
668 tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len,
669 group_id);
670 spin_unlock_irqrestore(&port_group_lock, flags);
671 if (tmp_pg) {
672 if (spin_trylock_irqsave(&tmp_pg->lock, flags)) {
673 if ((tmp_pg == pg) ||
674 !(tmp_pg->flags & ALUA_PG_RUNNING)) {
675 struct alua_dh_data *h;
676
677 tmp_pg->state = desc[0] & 0x0f;
678 tmp_pg->pref = desc[0] >> 7;
679 rcu_read_lock();
680 list_for_each_entry_rcu(h,
681 &tmp_pg->dh_list, node) {
682 if (!h->sdev)
683 continue;
684 h->sdev->access_state = desc[0];
685 }
686 rcu_read_unlock();
687 }
688 if (tmp_pg == pg)
689 tmp_pg->valid_states = desc[1];
690 spin_unlock_irqrestore(&tmp_pg->lock, flags);
691 }
692 kref_put(&tmp_pg->kref, release_port_group);
693 }
694 off = 8 + (desc[7] * 4);
695 }
696
697 skip_rtpg:
698 spin_lock_irqsave(&pg->lock, flags);
699 if (transitioning_sense)
700 pg->state = SCSI_ACCESS_STATE_TRANSITIONING;
701
702 if (group_id_old != pg->group_id || state_old != pg->state ||
703 pref_old != pg->pref || valid_states_old != pg->valid_states)
704 sdev_printk(KERN_INFO, sdev,
705 "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n",
706 ALUA_DH_NAME, pg->group_id, print_alua_state(pg->state),
707 pg->pref ? "preferred" : "non-preferred",
708 pg->valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
709 pg->valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
710 pg->valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
711 pg->valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
712 pg->valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
713 pg->valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
714 pg->valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
715
716 switch (pg->state) {
717 case SCSI_ACCESS_STATE_TRANSITIONING:
718 if (time_before(jiffies, pg->expiry)) {
719 /* State transition, retry */
720 pg->interval = ALUA_RTPG_RETRY_DELAY;
721 err = SCSI_DH_RETRY;
722 } else {
723 struct alua_dh_data *h;
724
725 /* Transitioning time exceeded, set port to standby */
726 err = SCSI_DH_IO;
727 pg->state = SCSI_ACCESS_STATE_STANDBY;
728 pg->expiry = 0;
729 rcu_read_lock();
730 list_for_each_entry_rcu(h, &pg->dh_list, node) {
731 if (!h->sdev)
732 continue;
733 h->sdev->access_state =
734 (pg->state & SCSI_ACCESS_STATE_MASK);
735 if (pg->pref)
736 h->sdev->access_state |=
737 SCSI_ACCESS_STATE_PREFERRED;
738 }
739 rcu_read_unlock();
740 }
741 break;
742 case SCSI_ACCESS_STATE_OFFLINE:
743 /* Path unusable */
744 err = SCSI_DH_DEV_OFFLINED;
745 pg->expiry = 0;
746 break;
747 default:
748 /* Useable path if active */
749 err = SCSI_DH_OK;
750 pg->expiry = 0;
751 break;
752 }
753 spin_unlock_irqrestore(&pg->lock, flags);
754 kfree(buff);
755 return err;
756}
757
758/*
759 * alua_stpg - Issue a SET TARGET PORT GROUP command
760 *
761 * Issue a SET TARGET PORT GROUP command and evaluate the
762 * response. Returns SCSI_DH_RETRY per default to trigger
763 * a re-evaluation of the target group state or SCSI_DH_OK
764 * if no further action needs to be taken.
765 */
766static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
767{
768 int retval;
769 struct scsi_sense_hdr sense_hdr;
770
771 if (!(pg->tpgs & TPGS_MODE_EXPLICIT)) {
772 /* Only implicit ALUA supported, retry */
773 return SCSI_DH_RETRY;
774 }
775 switch (pg->state) {
776 case SCSI_ACCESS_STATE_OPTIMAL:
777 return SCSI_DH_OK;
778 case SCSI_ACCESS_STATE_ACTIVE:
779 if ((pg->flags & ALUA_OPTIMIZE_STPG) &&
780 !pg->pref &&
781 (pg->tpgs & TPGS_MODE_IMPLICIT))
782 return SCSI_DH_OK;
783 break;
784 case SCSI_ACCESS_STATE_STANDBY:
785 case SCSI_ACCESS_STATE_UNAVAILABLE:
786 break;
787 case SCSI_ACCESS_STATE_OFFLINE:
788 return SCSI_DH_IO;
789 case SCSI_ACCESS_STATE_TRANSITIONING:
790 break;
791 default:
792 sdev_printk(KERN_INFO, sdev,
793 "%s: stpg failed, unhandled TPGS state %d",
794 ALUA_DH_NAME, pg->state);
795 return SCSI_DH_NOSYS;
796 }
797 retval = submit_stpg(sdev, pg->group_id, &sense_hdr);
798
799 if (retval) {
800 if (retval < 0 || !scsi_sense_valid(&sense_hdr)) {
801 sdev_printk(KERN_INFO, sdev,
802 "%s: stpg failed, result %d",
803 ALUA_DH_NAME, retval);
804 if (retval < 0)
805 return SCSI_DH_DEV_TEMP_BUSY;
806 } else {
807 sdev_printk(KERN_INFO, sdev, "%s: stpg failed\n",
808 ALUA_DH_NAME);
809 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
810 }
811 }
812 /* Retry RTPG */
813 return SCSI_DH_RETRY;
814}
815
816/*
817 * The caller must call scsi_device_put() on the returned pointer if it is not
818 * NULL.
819 */
820static struct scsi_device * __must_check
821alua_rtpg_select_sdev(struct alua_port_group *pg)
822{
823 struct alua_dh_data *h;
824 struct scsi_device *sdev = NULL, *prev_sdev;
825
826 lockdep_assert_held(&pg->lock);
827 if (WARN_ON(!pg->rtpg_sdev))
828 return NULL;
829
830 /*
831 * RCU protection isn't necessary for dh_list here
832 * as we hold pg->lock, but for access to h->pg.
833 */
834 rcu_read_lock();
835 list_for_each_entry_rcu(h, &pg->dh_list, node) {
836 if (!h->sdev)
837 continue;
838 if (h->sdev == pg->rtpg_sdev) {
839 h->disabled = true;
840 continue;
841 }
842 if (rcu_dereference(h->pg) == pg &&
843 !h->disabled &&
844 !scsi_device_get(h->sdev)) {
845 sdev = h->sdev;
846 break;
847 }
848 }
849 rcu_read_unlock();
850
851 if (!sdev) {
852 pr_warn("%s: no device found for rtpg\n",
853 (pg->device_id_len ?
854 (char *)pg->device_id_str : "(nameless PG)"));
855 return NULL;
856 }
857
858 sdev_printk(KERN_INFO, sdev, "rtpg retry on different device\n");
859
860 prev_sdev = pg->rtpg_sdev;
861 pg->rtpg_sdev = sdev;
862
863 return prev_sdev;
864}
865
866static void alua_rtpg_work(struct work_struct *work)
867{
868 struct alua_port_group *pg =
869 container_of(work, struct alua_port_group, rtpg_work.work);
870 struct scsi_device *sdev, *prev_sdev = NULL;
871 LIST_HEAD(qdata_list);
872 int err = SCSI_DH_OK;
873 struct alua_queue_data *qdata, *tmp;
874 struct alua_dh_data *h;
875 unsigned long flags;
876
877 spin_lock_irqsave(&pg->lock, flags);
878 sdev = pg->rtpg_sdev;
879 if (!sdev) {
880 WARN_ON(pg->flags & ALUA_PG_RUN_RTPG);
881 WARN_ON(pg->flags & ALUA_PG_RUN_STPG);
882 spin_unlock_irqrestore(&pg->lock, flags);
883 kref_put(&pg->kref, release_port_group);
884 return;
885 }
886 pg->flags |= ALUA_PG_RUNNING;
887 if (pg->flags & ALUA_PG_RUN_RTPG) {
888 int state = pg->state;
889
890 pg->flags &= ~ALUA_PG_RUN_RTPG;
891 spin_unlock_irqrestore(&pg->lock, flags);
892 if (state == SCSI_ACCESS_STATE_TRANSITIONING) {
893 if (alua_tur(sdev) == SCSI_DH_RETRY) {
894 spin_lock_irqsave(&pg->lock, flags);
895 pg->flags &= ~ALUA_PG_RUNNING;
896 pg->flags |= ALUA_PG_RUN_RTPG;
897 if (!pg->interval)
898 pg->interval = ALUA_RTPG_RETRY_DELAY;
899 spin_unlock_irqrestore(&pg->lock, flags);
900 queue_delayed_work(kaluad_wq, &pg->rtpg_work,
901 pg->interval * HZ);
902 return;
903 }
904 /* Send RTPG on failure or if TUR indicates SUCCESS */
905 }
906 err = alua_rtpg(sdev, pg);
907 spin_lock_irqsave(&pg->lock, flags);
908
909 /* If RTPG failed on the current device, try using another */
910 if (err == SCSI_DH_RES_TEMP_UNAVAIL &&
911 (prev_sdev = alua_rtpg_select_sdev(pg)))
912 err = SCSI_DH_IMM_RETRY;
913
914 if (err == SCSI_DH_RETRY || err == SCSI_DH_IMM_RETRY ||
915 pg->flags & ALUA_PG_RUN_RTPG) {
916 pg->flags &= ~ALUA_PG_RUNNING;
917 if (err == SCSI_DH_IMM_RETRY)
918 pg->interval = 0;
919 else if (!pg->interval && !(pg->flags & ALUA_PG_RUN_RTPG))
920 pg->interval = ALUA_RTPG_RETRY_DELAY;
921 pg->flags |= ALUA_PG_RUN_RTPG;
922 spin_unlock_irqrestore(&pg->lock, flags);
923 goto queue_rtpg;
924 }
925 if (err != SCSI_DH_OK)
926 pg->flags &= ~ALUA_PG_RUN_STPG;
927 }
928 if (pg->flags & ALUA_PG_RUN_STPG) {
929 pg->flags &= ~ALUA_PG_RUN_STPG;
930 spin_unlock_irqrestore(&pg->lock, flags);
931 err = alua_stpg(sdev, pg);
932 spin_lock_irqsave(&pg->lock, flags);
933 if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) {
934 pg->flags |= ALUA_PG_RUN_RTPG;
935 pg->interval = 0;
936 pg->flags &= ~ALUA_PG_RUNNING;
937 spin_unlock_irqrestore(&pg->lock, flags);
938 goto queue_rtpg;
939 }
940 }
941
942 list_splice_init(&pg->rtpg_list, &qdata_list);
943 /*
944 * We went through an RTPG, for good or bad.
945 * Re-enable all devices for the next attempt.
946 */
947 list_for_each_entry(h, &pg->dh_list, node)
948 h->disabled = false;
949 pg->rtpg_sdev = NULL;
950 spin_unlock_irqrestore(&pg->lock, flags);
951
952 if (prev_sdev)
953 scsi_device_put(prev_sdev);
954
955 list_for_each_entry_safe(qdata, tmp, &qdata_list, entry) {
956 list_del(&qdata->entry);
957 if (qdata->callback_fn)
958 qdata->callback_fn(qdata->callback_data, err);
959 kfree(qdata);
960 }
961 spin_lock_irqsave(&pg->lock, flags);
962 pg->flags &= ~ALUA_PG_RUNNING;
963 spin_unlock_irqrestore(&pg->lock, flags);
964 scsi_device_put(sdev);
965 kref_put(&pg->kref, release_port_group);
966 return;
967
968queue_rtpg:
969 if (prev_sdev)
970 scsi_device_put(prev_sdev);
971 queue_delayed_work(kaluad_wq, &pg->rtpg_work, pg->interval * HZ);
972}
973
974/**
975 * alua_rtpg_queue() - cause RTPG to be submitted asynchronously
976 * @pg: ALUA port group associated with @sdev.
977 * @sdev: SCSI device for which to submit an RTPG.
978 * @qdata: Information about the callback to invoke after the RTPG.
979 * @force: Whether or not to submit an RTPG if a work item that will submit an
980 * RTPG already has been scheduled.
981 *
982 * Returns true if and only if alua_rtpg_work() will be called asynchronously.
983 * That function is responsible for calling @qdata->fn().
984 *
985 * Context: may be called from atomic context (alua_check()) only if the caller
986 * holds an sdev reference.
987 */
988static bool alua_rtpg_queue(struct alua_port_group *pg,
989 struct scsi_device *sdev,
990 struct alua_queue_data *qdata, bool force)
991{
992 int start_queue = 0;
993 unsigned long flags;
994
995 if (WARN_ON_ONCE(!pg) || scsi_device_get(sdev))
996 return false;
997
998 spin_lock_irqsave(&pg->lock, flags);
999 if (qdata) {
1000 list_add_tail(&qdata->entry, &pg->rtpg_list);
1001 pg->flags |= ALUA_PG_RUN_STPG;
1002 force = true;
1003 }
1004 if (pg->rtpg_sdev == NULL) {
1005 struct alua_dh_data *h = sdev->handler_data;
1006
1007 rcu_read_lock();
1008 if (h && rcu_dereference(h->pg) == pg) {
1009 pg->interval = 0;
1010 pg->flags |= ALUA_PG_RUN_RTPG;
1011 kref_get(&pg->kref);
1012 pg->rtpg_sdev = sdev;
1013 start_queue = 1;
1014 }
1015 rcu_read_unlock();
1016 } else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force) {
1017 pg->flags |= ALUA_PG_RUN_RTPG;
1018 /* Do not queue if the worker is already running */
1019 if (!(pg->flags & ALUA_PG_RUNNING)) {
1020 kref_get(&pg->kref);
1021 start_queue = 1;
1022 }
1023 }
1024
1025 spin_unlock_irqrestore(&pg->lock, flags);
1026
1027 if (start_queue) {
1028 if (queue_delayed_work(kaluad_wq, &pg->rtpg_work,
1029 msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS)))
1030 sdev = NULL;
1031 else
1032 kref_put(&pg->kref, release_port_group);
1033 }
1034 if (sdev)
1035 scsi_device_put(sdev);
1036
1037 return true;
1038}
1039
1040/*
1041 * alua_initialize - Initialize ALUA state
1042 * @sdev: the device to be initialized
1043 *
1044 * For the prep_fn to work correctly we have
1045 * to initialize the ALUA state for the device.
1046 */
1047static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
1048{
1049 int err = SCSI_DH_DEV_UNSUPP, tpgs;
1050
1051 mutex_lock(&h->init_mutex);
1052 h->disabled = false;
1053 tpgs = alua_check_tpgs(sdev);
1054 if (tpgs != TPGS_MODE_NONE)
1055 err = alua_check_vpd(sdev, h, tpgs);
1056 h->init_error = err;
1057 mutex_unlock(&h->init_mutex);
1058 return err;
1059}
1060/*
1061 * alua_set_params - set/unset the optimize flag
1062 * @sdev: device on the path to be activated
1063 * params - parameters in the following format
1064 * "no_of_params\0param1\0param2\0param3\0...\0"
1065 * For example, to set the flag pass the following parameters
1066 * from multipath.conf
1067 * hardware_handler "2 alua 1"
1068 */
1069static int alua_set_params(struct scsi_device *sdev, const char *params)
1070{
1071 struct alua_dh_data *h = sdev->handler_data;
1072 struct alua_port_group *pg = NULL;
1073 unsigned int optimize = 0, argc;
1074 const char *p = params;
1075 int result = SCSI_DH_OK;
1076 unsigned long flags;
1077
1078 if ((sscanf(params, "%u", &argc) != 1) || (argc != 1))
1079 return -EINVAL;
1080
1081 while (*p++)
1082 ;
1083 if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1))
1084 return -EINVAL;
1085
1086 rcu_read_lock();
1087 pg = rcu_dereference(h->pg);
1088 if (!pg) {
1089 rcu_read_unlock();
1090 return -ENXIO;
1091 }
1092 spin_lock_irqsave(&pg->lock, flags);
1093 if (optimize)
1094 pg->flags |= ALUA_OPTIMIZE_STPG;
1095 else
1096 pg->flags &= ~ALUA_OPTIMIZE_STPG;
1097 spin_unlock_irqrestore(&pg->lock, flags);
1098 rcu_read_unlock();
1099
1100 return result;
1101}
1102
1103/*
1104 * alua_activate - activate a path
1105 * @sdev: device on the path to be activated
1106 *
1107 * We're currently switching the port group to be activated only and
1108 * let the array figure out the rest.
1109 * There may be other arrays which require us to switch all port groups
1110 * based on a certain policy. But until we actually encounter them it
1111 * should be okay.
1112 */
1113static int alua_activate(struct scsi_device *sdev,
1114 activate_complete fn, void *data)
1115{
1116 struct alua_dh_data *h = sdev->handler_data;
1117 int err = SCSI_DH_OK;
1118 struct alua_queue_data *qdata;
1119 struct alua_port_group *pg;
1120
1121 qdata = kzalloc(sizeof(*qdata), GFP_KERNEL);
1122 if (!qdata) {
1123 err = SCSI_DH_RES_TEMP_UNAVAIL;
1124 goto out;
1125 }
1126 qdata->callback_fn = fn;
1127 qdata->callback_data = data;
1128
1129 mutex_lock(&h->init_mutex);
1130 rcu_read_lock();
1131 pg = rcu_dereference(h->pg);
1132 if (!pg || !kref_get_unless_zero(&pg->kref)) {
1133 rcu_read_unlock();
1134 kfree(qdata);
1135 err = h->init_error;
1136 mutex_unlock(&h->init_mutex);
1137 goto out;
1138 }
1139 rcu_read_unlock();
1140 mutex_unlock(&h->init_mutex);
1141
1142 if (alua_rtpg_queue(pg, sdev, qdata, true))
1143 fn = NULL;
1144 else
1145 err = SCSI_DH_DEV_OFFLINED;
1146 kref_put(&pg->kref, release_port_group);
1147out:
1148 if (fn)
1149 fn(data, err);
1150 return 0;
1151}
1152
1153/*
1154 * alua_check - check path status
1155 * @sdev: device on the path to be checked
1156 *
1157 * Check the device status
1158 */
1159static void alua_check(struct scsi_device *sdev, bool force)
1160{
1161 struct alua_dh_data *h = sdev->handler_data;
1162 struct alua_port_group *pg;
1163
1164 rcu_read_lock();
1165 pg = rcu_dereference(h->pg);
1166 if (!pg || !kref_get_unless_zero(&pg->kref)) {
1167 rcu_read_unlock();
1168 return;
1169 }
1170 rcu_read_unlock();
1171 alua_rtpg_queue(pg, sdev, NULL, force);
1172 kref_put(&pg->kref, release_port_group);
1173}
1174
1175/*
1176 * alua_prep_fn - request callback
1177 *
1178 * Fail I/O to all paths not in state
1179 * active/optimized or active/non-optimized.
1180 */
1181static blk_status_t alua_prep_fn(struct scsi_device *sdev, struct request *req)
1182{
1183 struct alua_dh_data *h = sdev->handler_data;
1184 struct alua_port_group *pg;
1185 unsigned char state = SCSI_ACCESS_STATE_OPTIMAL;
1186
1187 rcu_read_lock();
1188 pg = rcu_dereference(h->pg);
1189 if (pg)
1190 state = pg->state;
1191 rcu_read_unlock();
1192
1193 switch (state) {
1194 case SCSI_ACCESS_STATE_OPTIMAL:
1195 case SCSI_ACCESS_STATE_ACTIVE:
1196 case SCSI_ACCESS_STATE_LBA:
1197 case SCSI_ACCESS_STATE_TRANSITIONING:
1198 return BLK_STS_OK;
1199 default:
1200 req->rq_flags |= RQF_QUIET;
1201 return BLK_STS_IOERR;
1202 }
1203}
1204
1205static void alua_rescan(struct scsi_device *sdev)
1206{
1207 struct alua_dh_data *h = sdev->handler_data;
1208
1209 alua_initialize(sdev, h);
1210}
1211
1212/*
1213 * alua_bus_attach - Attach device handler
1214 * @sdev: device to be attached to
1215 */
1216static int alua_bus_attach(struct scsi_device *sdev)
1217{
1218 struct alua_dh_data *h;
1219 int err;
1220
1221 h = kzalloc(sizeof(*h) , GFP_KERNEL);
1222 if (!h)
1223 return SCSI_DH_NOMEM;
1224 spin_lock_init(&h->pg_lock);
1225 rcu_assign_pointer(h->pg, NULL);
1226 h->init_error = SCSI_DH_OK;
1227 h->sdev = sdev;
1228 INIT_LIST_HEAD(&h->node);
1229
1230 mutex_init(&h->init_mutex);
1231 err = alua_initialize(sdev, h);
1232 if (err != SCSI_DH_OK && err != SCSI_DH_DEV_OFFLINED)
1233 goto failed;
1234
1235 sdev->handler_data = h;
1236 return SCSI_DH_OK;
1237failed:
1238 kfree(h);
1239 return err;
1240}
1241
1242/*
1243 * alua_bus_detach - Detach device handler
1244 * @sdev: device to be detached from
1245 */
1246static void alua_bus_detach(struct scsi_device *sdev)
1247{
1248 struct alua_dh_data *h = sdev->handler_data;
1249 struct alua_port_group *pg;
1250
1251 spin_lock(&h->pg_lock);
1252 pg = rcu_dereference_protected(h->pg, lockdep_is_held(&h->pg_lock));
1253 rcu_assign_pointer(h->pg, NULL);
1254 spin_unlock(&h->pg_lock);
1255 if (pg) {
1256 spin_lock_irq(&pg->lock);
1257 list_del_rcu(&h->node);
1258 spin_unlock_irq(&pg->lock);
1259 kref_put(&pg->kref, release_port_group);
1260 }
1261 sdev->handler_data = NULL;
1262 synchronize_rcu();
1263 kfree(h);
1264}
1265
1266static struct scsi_device_handler alua_dh = {
1267 .name = ALUA_DH_NAME,
1268 .module = THIS_MODULE,
1269 .attach = alua_bus_attach,
1270 .detach = alua_bus_detach,
1271 .prep_fn = alua_prep_fn,
1272 .check_sense = alua_check_sense,
1273 .activate = alua_activate,
1274 .rescan = alua_rescan,
1275 .set_params = alua_set_params,
1276};
1277
1278static int __init alua_init(void)
1279{
1280 int r;
1281
1282 kaluad_wq = alloc_workqueue("kaluad", WQ_MEM_RECLAIM, 0);
1283 if (!kaluad_wq)
1284 return -ENOMEM;
1285
1286 r = scsi_register_device_handler(&alua_dh);
1287 if (r != 0) {
1288 printk(KERN_ERR "%s: Failed to register scsi device handler",
1289 ALUA_DH_NAME);
1290 destroy_workqueue(kaluad_wq);
1291 }
1292 return r;
1293}
1294
1295static void __exit alua_exit(void)
1296{
1297 scsi_unregister_device_handler(&alua_dh);
1298 destroy_workqueue(kaluad_wq);
1299}
1300
1301module_init(alua_init);
1302module_exit(alua_exit);
1303
1304MODULE_DESCRIPTION("DM Multipath ALUA support");
1305MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
1306MODULE_LICENSE("GPL");
1307MODULE_VERSION(ALUA_DH_VER);