[SCSI] scsi_dh_alua: fix deadlock in stpg_endio
[linux-2.6.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 <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
57 struct 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
75 static char print_alua_state(int);
76 static int alua_check_sense(struct scsi_device *, struct scsi_sense_hdr *);
77
78 static 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
85 static 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
100 static 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  */
134 static 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);
163 done:
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  */
171 static 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);
200 done:
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  */
208 static 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);
239 done:
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  */
252 static 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_IO;
257
258         if (error || host_byte(req->errors) != DID_OK ||
259                         msg_byte(req->errors) != COMMAND_COMPLETE)
260                 goto done;
261
262         if (err == SCSI_DH_IO && h->senselen > 0) {
263                 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
264                                            &sense_hdr);
265                 if (!err) {
266                         err = SCSI_DH_IO;
267                         goto done;
268                 }
269                 err = alua_check_sense(h->sdev, &sense_hdr);
270                 if (err == ADD_TO_MLQUEUE) {
271                         err = SCSI_DH_RETRY;
272                         goto done;
273                 }
274                 sdev_printk(KERN_INFO, h->sdev,
275                             "%s: stpg sense code: %02x/%02x/%02x\n",
276                             ALUA_DH_NAME, sense_hdr.sense_key,
277                             sense_hdr.asc, sense_hdr.ascq);
278                 err = SCSI_DH_IO;
279         }
280         if (err == SCSI_DH_OK) {
281                 h->state = TPGS_STATE_OPTIMIZED;
282                 sdev_printk(KERN_INFO, h->sdev,
283                             "%s: port group %02x switched to state %c\n",
284                             ALUA_DH_NAME, h->group_id,
285                             print_alua_state(h->state));
286         }
287 done:
288         req->end_io_data = NULL;
289         __blk_put_request(req->q, req);
290         if (h->callback_fn) {
291                 h->callback_fn(h->callback_data, err);
292                 h->callback_fn = h->callback_data = NULL;
293         }
294         return;
295 }
296
297 /*
298  * submit_stpg - Issue a SET TARGET GROUP STATES command
299  *
300  * Currently we're only setting the current target port group state
301  * to 'active/optimized' and let the array firmware figure out
302  * the states of the remaining groups.
303  */
304 static unsigned submit_stpg(struct alua_dh_data *h)
305 {
306         struct request *rq;
307         int stpg_len = 8;
308         struct scsi_device *sdev = h->sdev;
309
310         /* Prepare the data buffer */
311         memset(h->buff, 0, stpg_len);
312         h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f;
313         h->buff[6] = (h->group_id >> 8) & 0xff;
314         h->buff[7] = h->group_id & 0xff;
315
316         rq = get_alua_req(sdev, h->buff, stpg_len, WRITE);
317         if (!rq)
318                 return SCSI_DH_RES_TEMP_UNAVAIL;
319
320         /* Prepare the command. */
321         rq->cmd[0] = MAINTENANCE_OUT;
322         rq->cmd[1] = MO_SET_TARGET_PGS;
323         rq->cmd[6] = (stpg_len >> 24) & 0xff;
324         rq->cmd[7] = (stpg_len >> 16) & 0xff;
325         rq->cmd[8] = (stpg_len >>  8) & 0xff;
326         rq->cmd[9] = stpg_len & 0xff;
327         rq->cmd_len = COMMAND_SIZE(MAINTENANCE_OUT);
328
329         rq->sense = h->sense;
330         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
331         rq->sense_len = h->senselen = 0;
332         rq->end_io_data = h;
333
334         blk_execute_rq_nowait(rq->q, NULL, rq, 1, stpg_endio);
335         return SCSI_DH_OK;
336 }
337
338 /*
339  * alua_std_inquiry - Evaluate standard INQUIRY command
340  * @sdev: device to be checked
341  *
342  * Just extract the TPGS setting to find out if ALUA
343  * is supported.
344  */
345 static int alua_std_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
346 {
347         int err;
348
349         err = submit_std_inquiry(sdev, h);
350
351         if (err != SCSI_DH_OK)
352                 return err;
353
354         /* Check TPGS setting */
355         h->tpgs = (h->inq[5] >> 4) & 0x3;
356         switch (h->tpgs) {
357         case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
358                 sdev_printk(KERN_INFO, sdev,
359                             "%s: supports implicit and explicit TPGS\n",
360                             ALUA_DH_NAME);
361                 break;
362         case TPGS_MODE_EXPLICIT:
363                 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n",
364                             ALUA_DH_NAME);
365                 break;
366         case TPGS_MODE_IMPLICIT:
367                 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n",
368                             ALUA_DH_NAME);
369                 break;
370         default:
371                 h->tpgs = TPGS_MODE_NONE;
372                 sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
373                             ALUA_DH_NAME);
374                 err = SCSI_DH_DEV_UNSUPP;
375                 break;
376         }
377
378         return err;
379 }
380
381 /*
382  * alua_vpd_inquiry - Evaluate INQUIRY vpd page 0x83
383  * @sdev: device to be checked
384  *
385  * Extract the relative target port and the target port group
386  * descriptor from the list of identificators.
387  */
388 static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
389 {
390         int len;
391         unsigned err;
392         unsigned char *d;
393
394  retry:
395         err = submit_vpd_inquiry(sdev, h);
396
397         if (err != SCSI_DH_OK)
398                 return err;
399
400         /* Check if vpd page exceeds initial buffer */
401         len = (h->buff[2] << 8) + h->buff[3] + 4;
402         if (len > h->bufflen) {
403                 /* Resubmit with the correct length */
404                 if (realloc_buffer(h, len)) {
405                         sdev_printk(KERN_WARNING, sdev,
406                                     "%s: kmalloc buffer failed\n",
407                                     ALUA_DH_NAME);
408                         /* Temporary failure, bypass */
409                         return SCSI_DH_DEV_TEMP_BUSY;
410                 }
411                 goto retry;
412         }
413
414         /*
415          * Now look for the correct descriptor.
416          */
417         d = h->buff + 4;
418         while (d < h->buff + len) {
419                 switch (d[1] & 0xf) {
420                 case 0x4:
421                         /* Relative target port */
422                         h->rel_port = (d[6] << 8) + d[7];
423                         break;
424                 case 0x5:
425                         /* Target port group */
426                         h->group_id = (d[6] << 8) + d[7];
427                         break;
428                 default:
429                         break;
430                 }
431                 d += d[3] + 4;
432         }
433
434         if (h->group_id == -1) {
435                 /*
436                  * Internal error; TPGS supported but required
437                  * VPD identification descriptors not present.
438                  * Disable ALUA support
439                  */
440                 sdev_printk(KERN_INFO, sdev,
441                             "%s: No target port descriptors found\n",
442                             ALUA_DH_NAME);
443                 h->state = TPGS_STATE_OPTIMIZED;
444                 h->tpgs = TPGS_MODE_NONE;
445                 err = SCSI_DH_DEV_UNSUPP;
446         } else {
447                 sdev_printk(KERN_INFO, sdev,
448                             "%s: port group %02x rel port %02x\n",
449                             ALUA_DH_NAME, h->group_id, h->rel_port);
450         }
451
452         return err;
453 }
454
455 static char print_alua_state(int state)
456 {
457         switch (state) {
458         case TPGS_STATE_OPTIMIZED:
459                 return 'A';
460         case TPGS_STATE_NONOPTIMIZED:
461                 return 'N';
462         case TPGS_STATE_STANDBY:
463                 return 'S';
464         case TPGS_STATE_UNAVAILABLE:
465                 return 'U';
466         case TPGS_STATE_LBA_DEPENDENT:
467                 return 'L';
468         case TPGS_STATE_OFFLINE:
469                 return 'O';
470         case TPGS_STATE_TRANSITIONING:
471                 return 'T';
472         default:
473                 return 'X';
474         }
475 }
476
477 static int alua_check_sense(struct scsi_device *sdev,
478                             struct scsi_sense_hdr *sense_hdr)
479 {
480         switch (sense_hdr->sense_key) {
481         case NOT_READY:
482                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a)
483                         /*
484                          * LUN Not Accessible - ALUA state transition
485                          */
486                         return ADD_TO_MLQUEUE;
487                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0b)
488                         /*
489                          * LUN Not Accessible -- Target port in standby state
490                          */
491                         return SUCCESS;
492                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0c)
493                         /*
494                          * LUN Not Accessible -- Target port in unavailable state
495                          */
496                         return SUCCESS;
497                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x12)
498                         /*
499                          * LUN Not Ready -- Offline
500                          */
501                         return SUCCESS;
502                 break;
503         case UNIT_ATTENTION:
504                 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
505                         /*
506                          * Power On, Reset, or Bus Device Reset, just retry.
507                          */
508                         return ADD_TO_MLQUEUE;
509                 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
510                         /*
511                          * ALUA state changed
512                          */
513                         return ADD_TO_MLQUEUE;
514                 }
515                 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
516                         /*
517                          * Implicit ALUA state transition failed
518                          */
519                         return ADD_TO_MLQUEUE;
520                 }
521                 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e) {
522                         /*
523                          * REPORTED_LUNS_DATA_HAS_CHANGED is reported
524                          * when switching controllers on targets like
525                          * Intel Multi-Flex. We can just retry.
526                          */
527                         return ADD_TO_MLQUEUE;
528                 }
529
530                 break;
531         }
532
533         return SCSI_RETURN_NOT_HANDLED;
534 }
535
536 /*
537  * alua_rtpg - Evaluate REPORT TARGET GROUP STATES
538  * @sdev: the device to be evaluated.
539  *
540  * Evaluate the Target Port Group State.
541  * Returns SCSI_DH_DEV_OFFLINED if the path is
542  * found to be unuseable.
543  */
544 static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
545 {
546         struct scsi_sense_hdr sense_hdr;
547         int len, k, off, valid_states = 0;
548         char *ucp;
549         unsigned err;
550         unsigned long expiry, interval = 10;
551
552         expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT);
553  retry:
554         err = submit_rtpg(sdev, h);
555
556         if (err == SCSI_DH_IO && h->senselen > 0) {
557                 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
558                                            &sense_hdr);
559                 if (!err)
560                         return SCSI_DH_IO;
561
562                 err = alua_check_sense(sdev, &sense_hdr);
563                 if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry))
564                         goto retry;
565                 sdev_printk(KERN_INFO, sdev,
566                             "%s: rtpg sense code %02x/%02x/%02x\n",
567                             ALUA_DH_NAME, sense_hdr.sense_key,
568                             sense_hdr.asc, sense_hdr.ascq);
569                 err = SCSI_DH_IO;
570         }
571         if (err != SCSI_DH_OK)
572                 return err;
573
574         len = (h->buff[0] << 24) + (h->buff[1] << 16) +
575                 (h->buff[2] << 8) + h->buff[3] + 4;
576
577         if (len > h->bufflen) {
578                 /* Resubmit with the correct length */
579                 if (realloc_buffer(h, len)) {
580                         sdev_printk(KERN_WARNING, sdev,
581                                     "%s: kmalloc buffer failed\n",__func__);
582                         /* Temporary failure, bypass */
583                         return SCSI_DH_DEV_TEMP_BUSY;
584                 }
585                 goto retry;
586         }
587
588         for (k = 4, ucp = h->buff + 4; k < len; k += off, ucp += off) {
589                 if (h->group_id == (ucp[2] << 8) + ucp[3]) {
590                         h->state = ucp[0] & 0x0f;
591                         valid_states = ucp[1];
592                 }
593                 off = 8 + (ucp[7] * 4);
594         }
595
596         sdev_printk(KERN_INFO, sdev,
597                     "%s: port group %02x state %c supports %c%c%c%c%c%c%c\n",
598                     ALUA_DH_NAME, h->group_id, print_alua_state(h->state),
599                     valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
600                     valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
601                     valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
602                     valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
603                     valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
604                     valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
605                     valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
606
607         switch (h->state) {
608         case TPGS_STATE_TRANSITIONING:
609                 if (time_before(jiffies, expiry)) {
610                         /* State transition, retry */
611                         interval *= 10;
612                         msleep(interval);
613                         goto retry;
614                 }
615                 /* Transitioning time exceeded, set port to standby */
616                 err = SCSI_DH_RETRY;
617                 h->state = TPGS_STATE_STANDBY;
618                 break;
619         case TPGS_STATE_OFFLINE:
620         case TPGS_STATE_UNAVAILABLE:
621                 /* Path unuseable for unavailable/offline */
622                 err = SCSI_DH_DEV_OFFLINED;
623                 break;
624         default:
625                 /* Useable path if active */
626                 err = SCSI_DH_OK;
627                 break;
628         }
629         return err;
630 }
631
632 /*
633  * alua_initialize - Initialize ALUA state
634  * @sdev: the device to be initialized
635  *
636  * For the prep_fn to work correctly we have
637  * to initialize the ALUA state for the device.
638  */
639 static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
640 {
641         int err;
642
643         err = alua_std_inquiry(sdev, h);
644         if (err != SCSI_DH_OK)
645                 goto out;
646
647         err = alua_vpd_inquiry(sdev, h);
648         if (err != SCSI_DH_OK)
649                 goto out;
650
651         err = alua_rtpg(sdev, h);
652         if (err != SCSI_DH_OK)
653                 goto out;
654
655 out:
656         return err;
657 }
658
659 /*
660  * alua_activate - activate a path
661  * @sdev: device on the path to be activated
662  *
663  * We're currently switching the port group to be activated only and
664  * let the array figure out the rest.
665  * There may be other arrays which require us to switch all port groups
666  * based on a certain policy. But until we actually encounter them it
667  * should be okay.
668  */
669 static int alua_activate(struct scsi_device *sdev,
670                         activate_complete fn, void *data)
671 {
672         struct alua_dh_data *h = get_alua_data(sdev);
673         int err = SCSI_DH_OK;
674
675         if (h->group_id != -1) {
676                 err = alua_rtpg(sdev, h);
677                 if (err != SCSI_DH_OK)
678                         goto out;
679         }
680
681         if (h->tpgs & TPGS_MODE_EXPLICIT &&
682             h->state != TPGS_STATE_OPTIMIZED &&
683             h->state != TPGS_STATE_LBA_DEPENDENT) {
684                 h->callback_fn = fn;
685                 h->callback_data = data;
686                 err = submit_stpg(h);
687                 if (err == SCSI_DH_OK)
688                         return 0;
689                 h->callback_fn = h->callback_data = NULL;
690         }
691
692 out:
693         if (fn)
694                 fn(data, err);
695         return 0;
696 }
697
698 /*
699  * alua_prep_fn - request callback
700  *
701  * Fail I/O to all paths not in state
702  * active/optimized or active/non-optimized.
703  */
704 static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
705 {
706         struct alua_dh_data *h = get_alua_data(sdev);
707         int ret = BLKPREP_OK;
708
709         if (h->state == TPGS_STATE_TRANSITIONING)
710                 ret = BLKPREP_DEFER;
711         else if (h->state != TPGS_STATE_OPTIMIZED &&
712                  h->state != TPGS_STATE_NONOPTIMIZED &&
713                  h->state != TPGS_STATE_LBA_DEPENDENT) {
714                 ret = BLKPREP_KILL;
715                 req->cmd_flags |= REQ_QUIET;
716         }
717         return ret;
718
719 }
720
721 static const struct scsi_dh_devlist alua_dev_list[] = {
722         {"HP", "MSA VOLUME" },
723         {"HP", "HSV101" },
724         {"HP", "HSV111" },
725         {"HP", "HSV200" },
726         {"HP", "HSV210" },
727         {"HP", "HSV300" },
728         {"IBM", "2107900" },
729         {"IBM", "2145" },
730         {"Pillar", "Axiom" },
731         {"Intel", "Multi-Flex"},
732         {"NETAPP", "LUN"},
733         {"AIX", "NVDISK"},
734         {NULL, NULL}
735 };
736
737 static int alua_bus_attach(struct scsi_device *sdev);
738 static void alua_bus_detach(struct scsi_device *sdev);
739
740 static struct scsi_device_handler alua_dh = {
741         .name = ALUA_DH_NAME,
742         .module = THIS_MODULE,
743         .devlist = alua_dev_list,
744         .attach = alua_bus_attach,
745         .detach = alua_bus_detach,
746         .prep_fn = alua_prep_fn,
747         .check_sense = alua_check_sense,
748         .activate = alua_activate,
749 };
750
751 /*
752  * alua_bus_attach - Attach device handler
753  * @sdev: device to be attached to
754  */
755 static int alua_bus_attach(struct scsi_device *sdev)
756 {
757         struct scsi_dh_data *scsi_dh_data;
758         struct alua_dh_data *h;
759         unsigned long flags;
760         int err = SCSI_DH_OK;
761
762         scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
763                                + sizeof(*h) , GFP_KERNEL);
764         if (!scsi_dh_data) {
765                 sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
766                             ALUA_DH_NAME);
767                 return -ENOMEM;
768         }
769
770         scsi_dh_data->scsi_dh = &alua_dh;
771         h = (struct alua_dh_data *) scsi_dh_data->buf;
772         h->tpgs = TPGS_MODE_UNINITIALIZED;
773         h->state = TPGS_STATE_OPTIMIZED;
774         h->group_id = -1;
775         h->rel_port = -1;
776         h->buff = h->inq;
777         h->bufflen = ALUA_INQUIRY_SIZE;
778         h->sdev = sdev;
779
780         err = alua_initialize(sdev, h);
781         if (err != SCSI_DH_OK)
782                 goto failed;
783
784         if (!try_module_get(THIS_MODULE))
785                 goto failed;
786
787         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
788         sdev->scsi_dh_data = scsi_dh_data;
789         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
790
791         return 0;
792
793 failed:
794         kfree(scsi_dh_data);
795         sdev_printk(KERN_ERR, sdev, "%s: not attached\n", ALUA_DH_NAME);
796         return -EINVAL;
797 }
798
799 /*
800  * alua_bus_detach - Detach device handler
801  * @sdev: device to be detached from
802  */
803 static void alua_bus_detach(struct scsi_device *sdev)
804 {
805         struct scsi_dh_data *scsi_dh_data;
806         struct alua_dh_data *h;
807         unsigned long flags;
808
809         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
810         scsi_dh_data = sdev->scsi_dh_data;
811         sdev->scsi_dh_data = NULL;
812         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
813
814         h = (struct alua_dh_data *) scsi_dh_data->buf;
815         if (h->buff && h->inq != h->buff)
816                 kfree(h->buff);
817         kfree(scsi_dh_data);
818         module_put(THIS_MODULE);
819         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", ALUA_DH_NAME);
820 }
821
822 static int __init alua_init(void)
823 {
824         int r;
825
826         r = scsi_register_device_handler(&alua_dh);
827         if (r != 0)
828                 printk(KERN_ERR "%s: Failed to register scsi device handler",
829                         ALUA_DH_NAME);
830         return r;
831 }
832
833 static void __exit alua_exit(void)
834 {
835         scsi_unregister_device_handler(&alua_dh);
836 }
837
838 module_init(alua_init);
839 module_exit(alua_exit);
840
841 MODULE_DESCRIPTION("DM Multipath ALUA support");
842 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
843 MODULE_LICENSE("GPL");
844 MODULE_VERSION(ALUA_DH_VER);