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scsi_dh: add 'rescan' callback
[mirror_ubuntu-artful-kernel.git] / drivers / scsi / device_handler / scsi_dh_alua.c
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 <linux/module.h>
25 #include <asm/unaligned.h>
26 #include <scsi/scsi.h>
27 #include <scsi/scsi_dbg.h>
28 #include <scsi/scsi_eh.h>
29 #include <scsi/scsi_dh.h>
30
31 #define ALUA_DH_NAME "alua"
32 #define ALUA_DH_VER "1.3"
33
34 #define TPGS_STATE_OPTIMIZED 0x0
35 #define TPGS_STATE_NONOPTIMIZED 0x1
36 #define TPGS_STATE_STANDBY 0x2
37 #define TPGS_STATE_UNAVAILABLE 0x3
38 #define TPGS_STATE_LBA_DEPENDENT 0x4
39 #define TPGS_STATE_OFFLINE 0xe
40 #define TPGS_STATE_TRANSITIONING 0xf
41
42 #define TPGS_SUPPORT_NONE 0x00
43 #define TPGS_SUPPORT_OPTIMIZED 0x01
44 #define TPGS_SUPPORT_NONOPTIMIZED 0x02
45 #define TPGS_SUPPORT_STANDBY 0x04
46 #define TPGS_SUPPORT_UNAVAILABLE 0x08
47 #define TPGS_SUPPORT_LBA_DEPENDENT 0x10
48 #define TPGS_SUPPORT_OFFLINE 0x40
49 #define TPGS_SUPPORT_TRANSITION 0x80
50
51 #define RTPG_FMT_MASK 0x70
52 #define RTPG_FMT_EXT_HDR 0x10
53
54 #define TPGS_MODE_UNINITIALIZED -1
55 #define TPGS_MODE_NONE 0x0
56 #define TPGS_MODE_IMPLICIT 0x1
57 #define TPGS_MODE_EXPLICIT 0x2
58
59 #define ALUA_RTPG_SIZE 128
60 #define ALUA_FAILOVER_TIMEOUT 60
61 #define ALUA_FAILOVER_RETRIES 5
62 #define ALUA_RTPG_DELAY_MSECS 5
63
64 /* device handler flags */
65 #define ALUA_OPTIMIZE_STPG 0x01
66 #define ALUA_RTPG_EXT_HDR_UNSUPP 0x02
67 #define ALUA_SYNC_STPG 0x04
68 /* State machine flags */
69 #define ALUA_PG_RUN_RTPG 0x10
70 #define ALUA_PG_RUN_STPG 0x20
71 #define ALUA_PG_RUNNING 0x40
72
73 static uint optimize_stpg;
74 module_param(optimize_stpg, uint, S_IRUGO|S_IWUSR);
75 MODULE_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.");
76
77 static LIST_HEAD(port_group_list);
78 static DEFINE_SPINLOCK(port_group_lock);
79 static struct workqueue_struct *kaluad_wq;
80 static struct workqueue_struct *kaluad_sync_wq;
81
82 struct alua_port_group {
83 struct kref kref;
84 struct rcu_head rcu;
85 struct list_head node;
86 unsigned char device_id_str[256];
87 int device_id_len;
88 int group_id;
89 int tpgs;
90 int state;
91 int pref;
92 unsigned flags; /* used for optimizing STPG */
93 unsigned char transition_tmo;
94 unsigned long expiry;
95 unsigned long interval;
96 struct delayed_work rtpg_work;
97 spinlock_t lock;
98 struct list_head rtpg_list;
99 struct scsi_device *rtpg_sdev;
100 };
101
102 struct alua_dh_data {
103 struct alua_port_group *pg;
104 int group_id;
105 spinlock_t pg_lock;
106 struct scsi_device *sdev;
107 int init_error;
108 struct mutex init_mutex;
109 };
110
111 struct alua_queue_data {
112 struct list_head entry;
113 activate_complete callback_fn;
114 void *callback_data;
115 };
116
117 #define ALUA_POLICY_SWITCH_CURRENT 0
118 #define ALUA_POLICY_SWITCH_ALL 1
119
120 static void alua_rtpg_work(struct work_struct *work);
121 static void alua_rtpg_queue(struct alua_port_group *pg,
122 struct scsi_device *sdev,
123 struct alua_queue_data *qdata, bool force);
124 static void alua_check(struct scsi_device *sdev, bool force);
125
126 static void release_port_group(struct kref *kref)
127 {
128 struct alua_port_group *pg;
129
130 pg = container_of(kref, struct alua_port_group, kref);
131 if (pg->rtpg_sdev)
132 flush_delayed_work(&pg->rtpg_work);
133 spin_lock(&port_group_lock);
134 list_del(&pg->node);
135 spin_unlock(&port_group_lock);
136 kfree_rcu(pg, rcu);
137 }
138
139 /*
140 * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
141 * @sdev: sdev the command should be sent to
142 */
143 static int submit_rtpg(struct scsi_device *sdev, unsigned char *buff,
144 int bufflen, struct scsi_sense_hdr *sshdr, int flags)
145 {
146 u8 cdb[COMMAND_SIZE(MAINTENANCE_IN)];
147 int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
148 REQ_FAILFAST_DRIVER;
149
150 /* Prepare the command. */
151 memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_IN));
152 cdb[0] = MAINTENANCE_IN;
153 if (!(flags & ALUA_RTPG_EXT_HDR_UNSUPP))
154 cdb[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT;
155 else
156 cdb[1] = MI_REPORT_TARGET_PGS;
157 put_unaligned_be32(bufflen, &cdb[6]);
158
159 return scsi_execute_req_flags(sdev, cdb, DMA_FROM_DEVICE,
160 buff, bufflen, sshdr,
161 ALUA_FAILOVER_TIMEOUT * HZ,
162 ALUA_FAILOVER_RETRIES, NULL, req_flags);
163 }
164
165 /*
166 * submit_stpg - Issue a SET TARGET PORT GROUP command
167 *
168 * Currently we're only setting the current target port group state
169 * to 'active/optimized' and let the array firmware figure out
170 * the states of the remaining groups.
171 */
172 static int submit_stpg(struct scsi_device *sdev, int group_id,
173 struct scsi_sense_hdr *sshdr)
174 {
175 u8 cdb[COMMAND_SIZE(MAINTENANCE_OUT)];
176 unsigned char stpg_data[8];
177 int stpg_len = 8;
178 int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
179 REQ_FAILFAST_DRIVER;
180
181 /* Prepare the data buffer */
182 memset(stpg_data, 0, stpg_len);
183 stpg_data[4] = TPGS_STATE_OPTIMIZED & 0x0f;
184 put_unaligned_be16(group_id, &stpg_data[6]);
185
186 /* Prepare the command. */
187 memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_OUT));
188 cdb[0] = MAINTENANCE_OUT;
189 cdb[1] = MO_SET_TARGET_PGS;
190 put_unaligned_be32(stpg_len, &cdb[6]);
191
192 return scsi_execute_req_flags(sdev, cdb, DMA_TO_DEVICE,
193 stpg_data, stpg_len,
194 sshdr, ALUA_FAILOVER_TIMEOUT * HZ,
195 ALUA_FAILOVER_RETRIES, NULL, req_flags);
196 }
197
198 struct alua_port_group *alua_find_get_pg(char *id_str, size_t id_size,
199 int group_id)
200 {
201 struct alua_port_group *pg;
202
203 list_for_each_entry(pg, &port_group_list, node) {
204 if (pg->group_id != group_id)
205 continue;
206 if (pg->device_id_len != id_size)
207 continue;
208 if (strncmp(pg->device_id_str, id_str, id_size))
209 continue;
210 if (!kref_get_unless_zero(&pg->kref))
211 continue;
212 return pg;
213 }
214
215 return NULL;
216 }
217
218 /*
219 * alua_alloc_pg - Allocate a new port_group structure
220 * @sdev: scsi device
221 * @h: alua device_handler data
222 * @group_id: port group id
223 *
224 * Allocate a new port_group structure for a given
225 * device.
226 */
227 struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev,
228 int group_id, int tpgs)
229 {
230 struct alua_port_group *pg, *tmp_pg;
231
232 pg = kzalloc(sizeof(struct alua_port_group), GFP_KERNEL);
233 if (!pg)
234 return ERR_PTR(-ENOMEM);
235
236 pg->device_id_len = scsi_vpd_lun_id(sdev, pg->device_id_str,
237 sizeof(pg->device_id_str));
238 if (pg->device_id_len <= 0) {
239 /*
240 * Internal error: TPGS supported but no device
241 * identifcation found. Disable ALUA support.
242 */
243 kfree(pg);
244 sdev_printk(KERN_INFO, sdev,
245 "%s: No device descriptors found\n",
246 ALUA_DH_NAME);
247 return ERR_PTR(-ENXIO);
248 }
249 pg->group_id = group_id;
250 pg->tpgs = tpgs;
251 pg->state = TPGS_STATE_OPTIMIZED;
252 if (optimize_stpg)
253 pg->flags |= ALUA_OPTIMIZE_STPG;
254 kref_init(&pg->kref);
255 INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work);
256 INIT_LIST_HEAD(&pg->rtpg_list);
257 INIT_LIST_HEAD(&pg->node);
258 spin_lock_init(&pg->lock);
259
260 spin_lock(&port_group_lock);
261 tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len,
262 group_id);
263 if (tmp_pg) {
264 spin_unlock(&port_group_lock);
265 kfree(pg);
266 return tmp_pg;
267 }
268
269 list_add(&pg->node, &port_group_list);
270 spin_unlock(&port_group_lock);
271
272 return pg;
273 }
274
275 /*
276 * alua_check_tpgs - Evaluate TPGS setting
277 * @sdev: device to be checked
278 *
279 * Examine the TPGS setting of the sdev to find out if ALUA
280 * is supported.
281 */
282 static int alua_check_tpgs(struct scsi_device *sdev)
283 {
284 int tpgs = TPGS_MODE_NONE;
285
286 /*
287 * ALUA support for non-disk devices is fraught with
288 * difficulties, so disable it for now.
289 */
290 if (sdev->type != TYPE_DISK) {
291 sdev_printk(KERN_INFO, sdev,
292 "%s: disable for non-disk devices\n",
293 ALUA_DH_NAME);
294 return tpgs;
295 }
296
297 tpgs = scsi_device_tpgs(sdev);
298 switch (tpgs) {
299 case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
300 sdev_printk(KERN_INFO, sdev,
301 "%s: supports implicit and explicit TPGS\n",
302 ALUA_DH_NAME);
303 break;
304 case TPGS_MODE_EXPLICIT:
305 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n",
306 ALUA_DH_NAME);
307 break;
308 case TPGS_MODE_IMPLICIT:
309 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n",
310 ALUA_DH_NAME);
311 break;
312 case TPGS_MODE_NONE:
313 sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
314 ALUA_DH_NAME);
315 break;
316 default:
317 sdev_printk(KERN_INFO, sdev,
318 "%s: unsupported TPGS setting %d\n",
319 ALUA_DH_NAME, tpgs);
320 tpgs = TPGS_MODE_NONE;
321 break;
322 }
323
324 return tpgs;
325 }
326
327 /*
328 * alua_check_vpd - Evaluate INQUIRY vpd page 0x83
329 * @sdev: device to be checked
330 *
331 * Extract the relative target port and the target port group
332 * descriptor from the list of identificators.
333 */
334 static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h,
335 int tpgs)
336 {
337 int rel_port = -1, group_id;
338 struct alua_port_group *pg, *old_pg = NULL;
339
340 group_id = scsi_vpd_tpg_id(sdev, &rel_port);
341 if (group_id < 0) {
342 /*
343 * Internal error; TPGS supported but required
344 * VPD identification descriptors not present.
345 * Disable ALUA support
346 */
347 sdev_printk(KERN_INFO, sdev,
348 "%s: No target port descriptors found\n",
349 ALUA_DH_NAME);
350 return SCSI_DH_DEV_UNSUPP;
351 }
352
353 pg = alua_alloc_pg(sdev, group_id, tpgs);
354 if (IS_ERR(pg)) {
355 if (PTR_ERR(pg) == -ENOMEM)
356 return SCSI_DH_NOMEM;
357 return SCSI_DH_DEV_UNSUPP;
358 }
359 sdev_printk(KERN_INFO, sdev,
360 "%s: device %s port group %x rel port %x\n",
361 ALUA_DH_NAME, pg->device_id_str, group_id, rel_port);
362
363 /* Check for existing port group references */
364 spin_lock(&h->pg_lock);
365 old_pg = h->pg;
366 if (old_pg != pg) {
367 /* port group has changed. Update to new port group */
368 rcu_assign_pointer(h->pg, pg);
369 }
370 if (sdev->synchronous_alua)
371 pg->flags |= ALUA_SYNC_STPG;
372 alua_rtpg_queue(h->pg, sdev, NULL, true);
373 spin_unlock(&h->pg_lock);
374
375 if (old_pg)
376 kref_put(&old_pg->kref, release_port_group);
377
378 return SCSI_DH_OK;
379 }
380
381 static char print_alua_state(int state)
382 {
383 switch (state) {
384 case TPGS_STATE_OPTIMIZED:
385 return 'A';
386 case TPGS_STATE_NONOPTIMIZED:
387 return 'N';
388 case TPGS_STATE_STANDBY:
389 return 'S';
390 case TPGS_STATE_UNAVAILABLE:
391 return 'U';
392 case TPGS_STATE_LBA_DEPENDENT:
393 return 'L';
394 case TPGS_STATE_OFFLINE:
395 return 'O';
396 case TPGS_STATE_TRANSITIONING:
397 return 'T';
398 default:
399 return 'X';
400 }
401 }
402
403 static int alua_check_sense(struct scsi_device *sdev,
404 struct scsi_sense_hdr *sense_hdr)
405 {
406 switch (sense_hdr->sense_key) {
407 case NOT_READY:
408 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) {
409 /*
410 * LUN Not Accessible - ALUA state transition
411 */
412 alua_check(sdev, false);
413 return NEEDS_RETRY;
414 }
415 break;
416 case UNIT_ATTENTION:
417 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) {
418 /*
419 * Power On, Reset, or Bus Device Reset.
420 * Might have obscured a state transition,
421 * so schedule a recheck.
422 */
423 alua_check(sdev, true);
424 return ADD_TO_MLQUEUE;
425 }
426 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x04)
427 /*
428 * Device internal reset
429 */
430 return ADD_TO_MLQUEUE;
431 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01)
432 /*
433 * Mode Parameters Changed
434 */
435 return ADD_TO_MLQUEUE;
436 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
437 /*
438 * ALUA state changed
439 */
440 alua_check(sdev, true);
441 return ADD_TO_MLQUEUE;
442 }
443 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
444 /*
445 * Implicit ALUA state transition failed
446 */
447 alua_check(sdev, true);
448 return ADD_TO_MLQUEUE;
449 }
450 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03)
451 /*
452 * Inquiry data has changed
453 */
454 return ADD_TO_MLQUEUE;
455 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e)
456 /*
457 * REPORTED_LUNS_DATA_HAS_CHANGED is reported
458 * when switching controllers on targets like
459 * Intel Multi-Flex. We can just retry.
460 */
461 return ADD_TO_MLQUEUE;
462 break;
463 }
464
465 return SCSI_RETURN_NOT_HANDLED;
466 }
467
468 /*
469 * alua_tur - Send a TEST UNIT READY
470 * @sdev: device to which the TEST UNIT READY command should be send
471 *
472 * Send a TEST UNIT READY to @sdev to figure out the device state
473 * Returns SCSI_DH_RETRY if the sense code is NOT READY/ALUA TRANSITIONING,
474 * SCSI_DH_OK if no error occurred, and SCSI_DH_IO otherwise.
475 */
476 static int alua_tur(struct scsi_device *sdev)
477 {
478 struct scsi_sense_hdr sense_hdr;
479 int retval;
480
481 retval = scsi_test_unit_ready(sdev, ALUA_FAILOVER_TIMEOUT * HZ,
482 ALUA_FAILOVER_RETRIES, &sense_hdr);
483 if (sense_hdr.sense_key == NOT_READY &&
484 sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a)
485 return SCSI_DH_RETRY;
486 else if (retval)
487 return SCSI_DH_IO;
488 else
489 return SCSI_DH_OK;
490 }
491
492 /*
493 * alua_rtpg - Evaluate REPORT TARGET GROUP STATES
494 * @sdev: the device to be evaluated.
495 *
496 * Evaluate the Target Port Group State.
497 * Returns SCSI_DH_DEV_OFFLINED if the path is
498 * found to be unusable.
499 */
500 static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
501 {
502 struct scsi_sense_hdr sense_hdr;
503 struct alua_port_group *tmp_pg;
504 int len, k, off, valid_states = 0, bufflen = ALUA_RTPG_SIZE;
505 unsigned char *desc, *buff;
506 unsigned err, retval;
507 unsigned int tpg_desc_tbl_off;
508 unsigned char orig_transition_tmo;
509 unsigned long flags;
510
511 if (!pg->expiry) {
512 unsigned long transition_tmo = ALUA_FAILOVER_TIMEOUT * HZ;
513
514 if (pg->transition_tmo)
515 transition_tmo = pg->transition_tmo * HZ;
516
517 pg->expiry = round_jiffies_up(jiffies + transition_tmo);
518 }
519
520 buff = kzalloc(bufflen, GFP_KERNEL);
521 if (!buff)
522 return SCSI_DH_DEV_TEMP_BUSY;
523
524 retry:
525 retval = submit_rtpg(sdev, buff, bufflen, &sense_hdr, pg->flags);
526
527 if (retval) {
528 if (!scsi_sense_valid(&sense_hdr)) {
529 sdev_printk(KERN_INFO, sdev,
530 "%s: rtpg failed, result %d\n",
531 ALUA_DH_NAME, retval);
532 kfree(buff);
533 if (driver_byte(retval) == DRIVER_ERROR)
534 return SCSI_DH_DEV_TEMP_BUSY;
535 return SCSI_DH_IO;
536 }
537
538 /*
539 * submit_rtpg() has failed on existing arrays
540 * when requesting extended header info, and
541 * the array doesn't support extended headers,
542 * even though it shouldn't according to T10.
543 * The retry without rtpg_ext_hdr_req set
544 * handles this.
545 */
546 if (!(pg->flags & ALUA_RTPG_EXT_HDR_UNSUPP) &&
547 sense_hdr.sense_key == ILLEGAL_REQUEST &&
548 sense_hdr.asc == 0x24 && sense_hdr.ascq == 0) {
549 pg->flags |= ALUA_RTPG_EXT_HDR_UNSUPP;
550 goto retry;
551 }
552 /*
553 * Retry on ALUA state transition or if any
554 * UNIT ATTENTION occurred.
555 */
556 if (sense_hdr.sense_key == NOT_READY &&
557 sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a)
558 err = SCSI_DH_RETRY;
559 else if (sense_hdr.sense_key == UNIT_ATTENTION)
560 err = SCSI_DH_RETRY;
561 if (err == SCSI_DH_RETRY &&
562 pg->expiry != 0 && time_before(jiffies, pg->expiry)) {
563 sdev_printk(KERN_ERR, sdev, "%s: rtpg retry\n",
564 ALUA_DH_NAME);
565 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
566 return err;
567 }
568 sdev_printk(KERN_ERR, sdev, "%s: rtpg failed\n",
569 ALUA_DH_NAME);
570 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
571 kfree(buff);
572 pg->expiry = 0;
573 return SCSI_DH_IO;
574 }
575
576 len = get_unaligned_be32(&buff[0]) + 4;
577
578 if (len > bufflen) {
579 /* Resubmit with the correct length */
580 kfree(buff);
581 bufflen = len;
582 buff = kmalloc(bufflen, GFP_KERNEL);
583 if (!buff) {
584 sdev_printk(KERN_WARNING, sdev,
585 "%s: kmalloc buffer failed\n",__func__);
586 /* Temporary failure, bypass */
587 pg->expiry = 0;
588 return SCSI_DH_DEV_TEMP_BUSY;
589 }
590 goto retry;
591 }
592
593 orig_transition_tmo = pg->transition_tmo;
594 if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && buff[5] != 0)
595 pg->transition_tmo = buff[5];
596 else
597 pg->transition_tmo = ALUA_FAILOVER_TIMEOUT;
598
599 if (orig_transition_tmo != pg->transition_tmo) {
600 sdev_printk(KERN_INFO, sdev,
601 "%s: transition timeout set to %d seconds\n",
602 ALUA_DH_NAME, pg->transition_tmo);
603 pg->expiry = jiffies + pg->transition_tmo * HZ;
604 }
605
606 if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR)
607 tpg_desc_tbl_off = 8;
608 else
609 tpg_desc_tbl_off = 4;
610
611 for (k = tpg_desc_tbl_off, desc = buff + tpg_desc_tbl_off;
612 k < len;
613 k += off, desc += off) {
614 u16 group_id = get_unaligned_be16(&desc[2]);
615
616 spin_lock_irqsave(&port_group_lock, flags);
617 tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len,
618 group_id);
619 spin_unlock_irqrestore(&port_group_lock, flags);
620 if (tmp_pg) {
621 if (spin_trylock_irqsave(&tmp_pg->lock, flags)) {
622 if ((tmp_pg == pg) ||
623 !(tmp_pg->flags & ALUA_PG_RUNNING)) {
624 tmp_pg->state = desc[0] & 0x0f;
625 tmp_pg->pref = desc[0] >> 7;
626 }
627 if (tmp_pg == pg)
628 valid_states = desc[1];
629 spin_unlock_irqrestore(&tmp_pg->lock, flags);
630 }
631 kref_put(&tmp_pg->kref, release_port_group);
632 }
633 off = 8 + (desc[7] * 4);
634 }
635
636 spin_lock_irqsave(&pg->lock, flags);
637 sdev_printk(KERN_INFO, sdev,
638 "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n",
639 ALUA_DH_NAME, pg->group_id, print_alua_state(pg->state),
640 pg->pref ? "preferred" : "non-preferred",
641 valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
642 valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
643 valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
644 valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
645 valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
646 valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
647 valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
648
649 switch (pg->state) {
650 case TPGS_STATE_TRANSITIONING:
651 if (time_before(jiffies, pg->expiry)) {
652 /* State transition, retry */
653 pg->interval = 2;
654 err = SCSI_DH_RETRY;
655 } else {
656 /* Transitioning time exceeded, set port to standby */
657 err = SCSI_DH_IO;
658 pg->state = TPGS_STATE_STANDBY;
659 pg->expiry = 0;
660 }
661 break;
662 case TPGS_STATE_OFFLINE:
663 /* Path unusable */
664 err = SCSI_DH_DEV_OFFLINED;
665 pg->expiry = 0;
666 break;
667 default:
668 /* Useable path if active */
669 err = SCSI_DH_OK;
670 pg->expiry = 0;
671 break;
672 }
673 spin_unlock_irqrestore(&pg->lock, flags);
674 kfree(buff);
675 return err;
676 }
677
678 /*
679 * alua_stpg - Issue a SET TARGET PORT GROUP command
680 *
681 * Issue a SET TARGET PORT GROUP command and evaluate the
682 * response. Returns SCSI_DH_RETRY per default to trigger
683 * a re-evaluation of the target group state or SCSI_DH_OK
684 * if no further action needs to be taken.
685 */
686 static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
687 {
688 int retval;
689 struct scsi_sense_hdr sense_hdr;
690
691 if (!(pg->tpgs & TPGS_MODE_EXPLICIT)) {
692 /* Only implicit ALUA supported, retry */
693 return SCSI_DH_RETRY;
694 }
695 switch (pg->state) {
696 case TPGS_STATE_OPTIMIZED:
697 return SCSI_DH_OK;
698 case TPGS_STATE_NONOPTIMIZED:
699 if ((pg->flags & ALUA_OPTIMIZE_STPG) &&
700 !pg->pref &&
701 (pg->tpgs & TPGS_MODE_IMPLICIT))
702 return SCSI_DH_OK;
703 break;
704 case TPGS_STATE_STANDBY:
705 case TPGS_STATE_UNAVAILABLE:
706 break;
707 case TPGS_STATE_OFFLINE:
708 return SCSI_DH_IO;
709 case TPGS_STATE_TRANSITIONING:
710 break;
711 default:
712 sdev_printk(KERN_INFO, sdev,
713 "%s: stpg failed, unhandled TPGS state %d",
714 ALUA_DH_NAME, pg->state);
715 return SCSI_DH_NOSYS;
716 }
717 retval = submit_stpg(sdev, pg->group_id, &sense_hdr);
718
719 if (retval) {
720 if (!scsi_sense_valid(&sense_hdr)) {
721 sdev_printk(KERN_INFO, sdev,
722 "%s: stpg failed, result %d",
723 ALUA_DH_NAME, retval);
724 if (driver_byte(retval) == DRIVER_ERROR)
725 return SCSI_DH_DEV_TEMP_BUSY;
726 } else {
727 sdev_printk(KERN_INFO, sdev, "%s: stpg failed\n",
728 ALUA_DH_NAME);
729 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
730 }
731 }
732 /* Retry RTPG */
733 return SCSI_DH_RETRY;
734 }
735
736 static void alua_rtpg_work(struct work_struct *work)
737 {
738 struct alua_port_group *pg =
739 container_of(work, struct alua_port_group, rtpg_work.work);
740 struct scsi_device *sdev;
741 LIST_HEAD(qdata_list);
742 int err = SCSI_DH_OK;
743 struct alua_queue_data *qdata, *tmp;
744 unsigned long flags;
745 struct workqueue_struct *alua_wq = kaluad_wq;
746
747 spin_lock_irqsave(&pg->lock, flags);
748 sdev = pg->rtpg_sdev;
749 if (!sdev) {
750 WARN_ON(pg->flags & ALUA_PG_RUN_RTPG);
751 WARN_ON(pg->flags & ALUA_PG_RUN_STPG);
752 spin_unlock_irqrestore(&pg->lock, flags);
753 return;
754 }
755 if (pg->flags & ALUA_SYNC_STPG)
756 alua_wq = kaluad_sync_wq;
757 pg->flags |= ALUA_PG_RUNNING;
758 if (pg->flags & ALUA_PG_RUN_RTPG) {
759 int state = pg->state;
760
761 pg->flags &= ~ALUA_PG_RUN_RTPG;
762 spin_unlock_irqrestore(&pg->lock, flags);
763 if (state == TPGS_STATE_TRANSITIONING) {
764 if (alua_tur(sdev) == SCSI_DH_RETRY) {
765 spin_lock_irqsave(&pg->lock, flags);
766 pg->flags &= ~ALUA_PG_RUNNING;
767 pg->flags |= ALUA_PG_RUN_RTPG;
768 spin_unlock_irqrestore(&pg->lock, flags);
769 queue_delayed_work(alua_wq, &pg->rtpg_work,
770 pg->interval * HZ);
771 return;
772 }
773 /* Send RTPG on failure or if TUR indicates SUCCESS */
774 }
775 err = alua_rtpg(sdev, pg);
776 spin_lock_irqsave(&pg->lock, flags);
777 if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) {
778 pg->flags &= ~ALUA_PG_RUNNING;
779 pg->flags |= ALUA_PG_RUN_RTPG;
780 spin_unlock_irqrestore(&pg->lock, flags);
781 queue_delayed_work(alua_wq, &pg->rtpg_work,
782 pg->interval * HZ);
783 return;
784 }
785 if (err != SCSI_DH_OK)
786 pg->flags &= ~ALUA_PG_RUN_STPG;
787 }
788 if (pg->flags & ALUA_PG_RUN_STPG) {
789 pg->flags &= ~ALUA_PG_RUN_STPG;
790 spin_unlock_irqrestore(&pg->lock, flags);
791 err = alua_stpg(sdev, pg);
792 spin_lock_irqsave(&pg->lock, flags);
793 if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) {
794 pg->flags |= ALUA_PG_RUN_RTPG;
795 pg->interval = 0;
796 pg->flags &= ~ALUA_PG_RUNNING;
797 spin_unlock_irqrestore(&pg->lock, flags);
798 queue_delayed_work(alua_wq, &pg->rtpg_work,
799 pg->interval * HZ);
800 return;
801 }
802 }
803
804 list_splice_init(&pg->rtpg_list, &qdata_list);
805 pg->rtpg_sdev = NULL;
806 spin_unlock_irqrestore(&pg->lock, flags);
807
808 list_for_each_entry_safe(qdata, tmp, &qdata_list, entry) {
809 list_del(&qdata->entry);
810 if (qdata->callback_fn)
811 qdata->callback_fn(qdata->callback_data, err);
812 kfree(qdata);
813 }
814 spin_lock_irqsave(&pg->lock, flags);
815 pg->flags &= ~ALUA_PG_RUNNING;
816 spin_unlock_irqrestore(&pg->lock, flags);
817 scsi_device_put(sdev);
818 kref_put(&pg->kref, release_port_group);
819 }
820
821 static void alua_rtpg_queue(struct alua_port_group *pg,
822 struct scsi_device *sdev,
823 struct alua_queue_data *qdata, bool force)
824 {
825 int start_queue = 0;
826 unsigned long flags;
827 struct workqueue_struct *alua_wq = kaluad_wq;
828
829 if (!pg)
830 return;
831
832 spin_lock_irqsave(&pg->lock, flags);
833 if (qdata) {
834 list_add_tail(&qdata->entry, &pg->rtpg_list);
835 pg->flags |= ALUA_PG_RUN_STPG;
836 force = true;
837 }
838 if (pg->rtpg_sdev == NULL) {
839 pg->interval = 0;
840 pg->flags |= ALUA_PG_RUN_RTPG;
841 kref_get(&pg->kref);
842 pg->rtpg_sdev = sdev;
843 scsi_device_get(sdev);
844 start_queue = 1;
845 } else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force) {
846 pg->flags |= ALUA_PG_RUN_RTPG;
847 /* Do not queue if the worker is already running */
848 if (!(pg->flags & ALUA_PG_RUNNING)) {
849 kref_get(&pg->kref);
850 start_queue = 1;
851 }
852 }
853
854 if (pg->flags & ALUA_SYNC_STPG)
855 alua_wq = kaluad_sync_wq;
856 spin_unlock_irqrestore(&pg->lock, flags);
857
858 if (start_queue &&
859 !queue_delayed_work(alua_wq, &pg->rtpg_work,
860 msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS))) {
861 scsi_device_put(sdev);
862 kref_put(&pg->kref, release_port_group);
863 }
864 }
865
866 /*
867 * alua_initialize - Initialize ALUA state
868 * @sdev: the device to be initialized
869 *
870 * For the prep_fn to work correctly we have
871 * to initialize the ALUA state for the device.
872 */
873 static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
874 {
875 int err = SCSI_DH_DEV_UNSUPP, tpgs;
876
877 mutex_lock(&h->init_mutex);
878 tpgs = alua_check_tpgs(sdev);
879 if (tpgs != TPGS_MODE_NONE)
880 err = alua_check_vpd(sdev, h, tpgs);
881 h->init_error = err;
882 mutex_unlock(&h->init_mutex);
883 return err;
884 }
885 /*
886 * alua_set_params - set/unset the optimize flag
887 * @sdev: device on the path to be activated
888 * params - parameters in the following format
889 * "no_of_params\0param1\0param2\0param3\0...\0"
890 * For example, to set the flag pass the following parameters
891 * from multipath.conf
892 * hardware_handler "2 alua 1"
893 */
894 static int alua_set_params(struct scsi_device *sdev, const char *params)
895 {
896 struct alua_dh_data *h = sdev->handler_data;
897 struct alua_port_group __rcu *pg = NULL;
898 unsigned int optimize = 0, argc;
899 const char *p = params;
900 int result = SCSI_DH_OK;
901 unsigned long flags;
902
903 if ((sscanf(params, "%u", &argc) != 1) || (argc != 1))
904 return -EINVAL;
905
906 while (*p++)
907 ;
908 if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1))
909 return -EINVAL;
910
911 rcu_read_lock();
912 pg = rcu_dereference(h->pg);
913 if (!pg) {
914 rcu_read_unlock();
915 return -ENXIO;
916 }
917 spin_lock_irqsave(&pg->lock, flags);
918 if (optimize)
919 pg->flags |= ALUA_OPTIMIZE_STPG;
920 else
921 pg->flags &= ~ALUA_OPTIMIZE_STPG;
922 spin_unlock_irqrestore(&pg->lock, flags);
923 rcu_read_unlock();
924
925 return result;
926 }
927
928 /*
929 * alua_activate - activate a path
930 * @sdev: device on the path to be activated
931 *
932 * We're currently switching the port group to be activated only and
933 * let the array figure out the rest.
934 * There may be other arrays which require us to switch all port groups
935 * based on a certain policy. But until we actually encounter them it
936 * should be okay.
937 */
938 static int alua_activate(struct scsi_device *sdev,
939 activate_complete fn, void *data)
940 {
941 struct alua_dh_data *h = sdev->handler_data;
942 int err = SCSI_DH_OK;
943 struct alua_queue_data *qdata;
944 struct alua_port_group __rcu *pg;
945
946 qdata = kzalloc(sizeof(*qdata), GFP_KERNEL);
947 if (!qdata) {
948 err = SCSI_DH_RES_TEMP_UNAVAIL;
949 goto out;
950 }
951 qdata->callback_fn = fn;
952 qdata->callback_data = data;
953
954 mutex_lock(&h->init_mutex);
955 rcu_read_lock();
956 pg = rcu_dereference(h->pg);
957 if (!pg || !kref_get_unless_zero(&pg->kref)) {
958 rcu_read_unlock();
959 kfree(qdata);
960 err = h->init_error;
961 mutex_unlock(&h->init_mutex);
962 goto out;
963 }
964 fn = NULL;
965 rcu_read_unlock();
966 mutex_unlock(&h->init_mutex);
967
968 alua_rtpg_queue(pg, sdev, qdata, true);
969 kref_put(&pg->kref, release_port_group);
970 out:
971 if (fn)
972 fn(data, err);
973 return 0;
974 }
975
976 /*
977 * alua_check - check path status
978 * @sdev: device on the path to be checked
979 *
980 * Check the device status
981 */
982 static void alua_check(struct scsi_device *sdev, bool force)
983 {
984 struct alua_dh_data *h = sdev->handler_data;
985 struct alua_port_group *pg;
986
987 rcu_read_lock();
988 pg = rcu_dereference(h->pg);
989 if (!pg || !kref_get_unless_zero(&pg->kref)) {
990 rcu_read_unlock();
991 return;
992 }
993 rcu_read_unlock();
994
995 alua_rtpg_queue(pg, sdev, NULL, force);
996 kref_put(&pg->kref, release_port_group);
997 }
998
999 /*
1000 * alua_prep_fn - request callback
1001 *
1002 * Fail I/O to all paths not in state
1003 * active/optimized or active/non-optimized.
1004 */
1005 static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
1006 {
1007 struct alua_dh_data *h = sdev->handler_data;
1008 struct alua_port_group __rcu *pg;
1009 int state = TPGS_STATE_OPTIMIZED;
1010 int ret = BLKPREP_OK;
1011
1012 rcu_read_lock();
1013 pg = rcu_dereference(h->pg);
1014 if (pg)
1015 state = pg->state;
1016 rcu_read_unlock();
1017 if (state == TPGS_STATE_TRANSITIONING)
1018 ret = BLKPREP_DEFER;
1019 else if (state != TPGS_STATE_OPTIMIZED &&
1020 state != TPGS_STATE_NONOPTIMIZED &&
1021 state != TPGS_STATE_LBA_DEPENDENT) {
1022 ret = BLKPREP_KILL;
1023 req->cmd_flags |= REQ_QUIET;
1024 }
1025 return ret;
1026
1027 }
1028
1029 static void alua_rescan(struct scsi_device *sdev)
1030 {
1031 struct alua_dh_data *h = sdev->handler_data;
1032
1033 alua_initialize(sdev, h);
1034 }
1035
1036 /*
1037 * alua_bus_attach - Attach device handler
1038 * @sdev: device to be attached to
1039 */
1040 static int alua_bus_attach(struct scsi_device *sdev)
1041 {
1042 struct alua_dh_data *h;
1043 int err, ret = -EINVAL;
1044
1045 h = kzalloc(sizeof(*h) , GFP_KERNEL);
1046 if (!h)
1047 return -ENOMEM;
1048 spin_lock_init(&h->pg_lock);
1049 rcu_assign_pointer(h->pg, NULL);
1050 h->init_error = SCSI_DH_OK;
1051 h->sdev = sdev;
1052
1053 mutex_init(&h->init_mutex);
1054 err = alua_initialize(sdev, h);
1055 if (err == SCSI_DH_NOMEM)
1056 ret = -ENOMEM;
1057 if (err != SCSI_DH_OK && err != SCSI_DH_DEV_OFFLINED)
1058 goto failed;
1059
1060 sdev->handler_data = h;
1061 return 0;
1062 failed:
1063 kfree(h);
1064 return ret;
1065 }
1066
1067 /*
1068 * alua_bus_detach - Detach device handler
1069 * @sdev: device to be detached from
1070 */
1071 static void alua_bus_detach(struct scsi_device *sdev)
1072 {
1073 struct alua_dh_data *h = sdev->handler_data;
1074 struct alua_port_group *pg;
1075
1076 spin_lock(&h->pg_lock);
1077 pg = h->pg;
1078 rcu_assign_pointer(h->pg, NULL);
1079 h->sdev = NULL;
1080 spin_unlock(&h->pg_lock);
1081 if (pg)
1082 kref_put(&pg->kref, release_port_group);
1083
1084 sdev->handler_data = NULL;
1085 kfree(h);
1086 }
1087
1088 static struct scsi_device_handler alua_dh = {
1089 .name = ALUA_DH_NAME,
1090 .module = THIS_MODULE,
1091 .attach = alua_bus_attach,
1092 .detach = alua_bus_detach,
1093 .prep_fn = alua_prep_fn,
1094 .check_sense = alua_check_sense,
1095 .activate = alua_activate,
1096 .rescan = alua_rescan,
1097 .set_params = alua_set_params,
1098 };
1099
1100 static int __init alua_init(void)
1101 {
1102 int r;
1103
1104 kaluad_wq = alloc_workqueue("kaluad", WQ_MEM_RECLAIM, 0);
1105 if (!kaluad_wq) {
1106 /* Temporary failure, bypass */
1107 return SCSI_DH_DEV_TEMP_BUSY;
1108 }
1109 kaluad_sync_wq = create_workqueue("kaluad_sync");
1110 if (!kaluad_sync_wq) {
1111 destroy_workqueue(kaluad_wq);
1112 return SCSI_DH_DEV_TEMP_BUSY;
1113 }
1114 r = scsi_register_device_handler(&alua_dh);
1115 if (r != 0) {
1116 printk(KERN_ERR "%s: Failed to register scsi device handler",
1117 ALUA_DH_NAME);
1118 destroy_workqueue(kaluad_sync_wq);
1119 destroy_workqueue(kaluad_wq);
1120 }
1121 return r;
1122 }
1123
1124 static void __exit alua_exit(void)
1125 {
1126 scsi_unregister_device_handler(&alua_dh);
1127 destroy_workqueue(kaluad_sync_wq);
1128 destroy_workqueue(kaluad_wq);
1129 }
1130
1131 module_init(alua_init);
1132 module_exit(alua_exit);
1133
1134 MODULE_DESCRIPTION("DM Multipath ALUA support");
1135 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
1136 MODULE_LICENSE("GPL");
1137 MODULE_VERSION(ALUA_DH_VER);
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