2 * Copyright (C) 2004 SUSE LINUX Products GmbH. All rights reserved.
3 * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
5 * This file is released under the GPL.
7 * Multipath support for EMC CLARiiON AX/CX-series hardware.
11 #include "dm-hw-handler.h"
12 #include <scsi/scsi.h>
13 #include <scsi/scsi_cmnd.h>
15 #define DM_MSG_PREFIX "multipath emc"
20 /* Whether we should send the short trespass command (FC-series)
21 * or the long version (default for AX/CX CLARiiON arrays). */
22 unsigned short_trespass
;
23 /* Whether or not to honor SCSI reservations when initiating a
24 * switch-over. Default: Don't. */
27 unsigned char sense
[SCSI_SENSE_BUFFERSIZE
];
30 #define TRESPASS_PAGE 0x22
31 #define EMC_FAILOVER_TIMEOUT (60 * HZ)
33 /* Code borrowed from dm-lsi-rdac by Mike Christie */
35 static inline void free_bio(struct bio
*bio
)
37 __free_page(bio
->bi_io_vec
[0].bv_page
);
41 static void emc_endio(struct bio
*bio
, int error
)
43 struct dm_path
*path
= bio
->bi_private
;
45 /* We also need to look at the sense keys here whether or not to
46 * switch to the next PG etc.
48 * For now simple logic: either it works or it doesn't.
51 dm_pg_init_complete(path
, MP_FAIL_PATH
);
53 dm_pg_init_complete(path
, 0);
55 /* request is freed in block layer */
61 static struct bio
*get_failover_bio(struct dm_path
*path
, unsigned data_size
)
66 bio
= bio_alloc(GFP_ATOMIC
, 1);
68 DMERR("get_failover_bio: bio_alloc() failed.");
72 bio
->bi_rw
|= (1 << BIO_RW
);
73 bio
->bi_bdev
= path
->dev
->bdev
;
75 bio
->bi_private
= path
;
76 bio
->bi_end_io
= emc_endio
;
78 page
= alloc_page(GFP_ATOMIC
);
80 DMERR("get_failover_bio: alloc_page() failed.");
85 if (bio_add_page(bio
, page
, data_size
, 0) != data_size
) {
86 DMERR("get_failover_bio: alloc_page() failed.");
95 static struct request
*get_failover_req(struct emc_handler
*h
,
96 struct bio
*bio
, struct dm_path
*path
)
99 struct block_device
*bdev
= bio
->bi_bdev
;
100 struct request_queue
*q
= bdev_get_queue(bdev
);
102 /* FIXME: Figure out why it fails with GFP_ATOMIC. */
103 rq
= blk_get_request(q
, WRITE
, __GFP_WAIT
);
105 DMERR("get_failover_req: blk_get_request failed");
109 blk_rq_append_bio(q
, rq
, bio
);
111 rq
->sense
= h
->sense
;
112 memset(rq
->sense
, 0, SCSI_SENSE_BUFFERSIZE
);
115 memset(&rq
->cmd
, 0, BLK_MAX_CDB
);
117 rq
->timeout
= EMC_FAILOVER_TIMEOUT
;
118 rq
->cmd_type
= REQ_TYPE_BLOCK_PC
;
119 rq
->cmd_flags
|= REQ_FAILFAST
| REQ_NOMERGE
;
124 static struct request
*emc_trespass_get(struct emc_handler
*h
,
125 struct dm_path
*path
)
129 unsigned char *page22
;
130 unsigned char long_trespass_pg
[] = {
132 TRESPASS_PAGE
, /* Page code */
133 0x09, /* Page length - 2 */
134 h
->hr
? 0x01 : 0x81, /* Trespass code + Honor reservation bit */
135 0xff, 0xff, /* Trespass target */
136 0, 0, 0, 0, 0, 0 /* Reserved bytes / unknown */
138 unsigned char short_trespass_pg
[] = {
140 TRESPASS_PAGE
, /* Page code */
141 0x02, /* Page length - 2 */
142 h
->hr
? 0x01 : 0x81, /* Trespass code + Honor reservation bit */
143 0xff, /* Trespass target */
145 unsigned data_size
= h
->short_trespass
? sizeof(short_trespass_pg
) :
146 sizeof(long_trespass_pg
);
148 /* get bio backing */
149 if (data_size
> PAGE_SIZE
)
150 /* this should never happen */
153 bio
= get_failover_bio(path
, data_size
);
155 DMERR("emc_trespass_get: no bio");
159 page22
= (unsigned char *)bio_data(bio
);
160 memset(page22
, 0, data_size
);
162 memcpy(page22
, h
->short_trespass
?
163 short_trespass_pg
: long_trespass_pg
, data_size
);
165 /* get request for block layer packet command */
166 rq
= get_failover_req(h
, bio
, path
);
168 DMERR("emc_trespass_get: no rq");
173 /* Prepare the command. */
174 rq
->cmd
[0] = MODE_SELECT
;
176 rq
->cmd
[4] = data_size
;
177 rq
->cmd_len
= COMMAND_SIZE(rq
->cmd
[0]);
182 static void emc_pg_init(struct hw_handler
*hwh
, unsigned bypassed
,
183 struct dm_path
*path
)
186 struct request_queue
*q
= bdev_get_queue(path
->dev
->bdev
);
189 * We can either blindly init the pg (then look at the sense),
190 * or we can send some commands to get the state here (then
191 * possibly send the fo cmnd), or we can also have the
192 * initial state passed into us and then get an update here.
195 DMINFO("emc_pg_init: no queue");
199 /* FIXME: The request should be pre-allocated. */
200 rq
= emc_trespass_get(hwh
->context
, path
);
202 DMERR("emc_pg_init: no rq");
206 DMINFO("emc_pg_init: sending switch-over command");
207 elv_add_request(q
, rq
, ELEVATOR_INSERT_FRONT
, 1);
211 dm_pg_init_complete(path
, MP_FAIL_PATH
);
214 static struct emc_handler
*alloc_emc_handler(void)
216 struct emc_handler
*h
= kmalloc(sizeof(*h
), GFP_KERNEL
);
219 memset(h
, 0, sizeof(*h
));
220 spin_lock_init(&h
->lock
);
226 static int emc_create(struct hw_handler
*hwh
, unsigned argc
, char **argv
)
228 struct emc_handler
*h
;
229 unsigned hr
, short_trespass
;
232 /* No arguments: use defaults */
235 } else if (argc
!= 2) {
236 DMWARN("incorrect number of arguments");
239 if ((sscanf(argv
[0], "%u", &short_trespass
) != 1)
240 || (short_trespass
> 1)) {
241 DMWARN("invalid trespass mode selected");
245 if ((sscanf(argv
[1], "%u", &hr
) != 1)
247 DMWARN("invalid honor reservation flag selected");
252 h
= alloc_emc_handler();
258 if ((h
->short_trespass
= short_trespass
))
259 DMWARN("short trespass command will be send");
261 DMWARN("long trespass command will be send");
264 DMWARN("honor reservation bit will be set");
266 DMWARN("honor reservation bit will not be set (default)");
271 static void emc_destroy(struct hw_handler
*hwh
)
273 struct emc_handler
*h
= (struct emc_handler
*) hwh
->context
;
279 static unsigned emc_error(struct hw_handler
*hwh
, struct bio
*bio
)
281 /* FIXME: Patch from axboe still missing */
285 if (bio
->bi_error
& BIO_SENSE
) {
286 sense
= bio
->bi_error
& 0xffffff; /* sense key / asc / ascq */
288 if (sense
== 0x020403) {
289 /* LUN Not Ready - Manual Intervention Required
290 * indicates this is a passive path.
292 * FIXME: However, if this is seen and EVPD C0
293 * indicates that this is due to a NDU in
294 * progress, we should set FAIL_PATH too.
295 * This indicates we might have to do a SCSI
296 * inquiry in the end_io path. Ugh. */
297 return MP_BYPASS_PG
| MP_RETRY_IO
;
298 } else if (sense
== 0x052501) {
299 /* An array based copy is in progress. Do not
300 * fail the path, do not bypass to another PG,
301 * do not retry. Fail the IO immediately.
302 * (Actually this is the same conclusion as in
303 * the default handler, but lets make sure.) */
305 } else if (sense
== 0x062900) {
306 /* Unit Attention Code. This is the first IO
307 * to the new path, so just retry. */
313 /* Try default handler */
314 return dm_scsi_err_handler(hwh
, bio
);
317 static struct hw_handler_type emc_hwh
= {
319 .module
= THIS_MODULE
,
320 .create
= emc_create
,
321 .destroy
= emc_destroy
,
322 .pg_init
= emc_pg_init
,
326 static int __init
dm_emc_init(void)
328 int r
= dm_register_hw_handler(&emc_hwh
);
331 DMERR("register failed %d", r
);
333 DMINFO("version 0.0.3 loaded");
338 static void __exit
dm_emc_exit(void)
340 int r
= dm_unregister_hw_handler(&emc_hwh
);
343 DMERR("unregister failed %d", r
);
346 module_init(dm_emc_init
);
347 module_exit(dm_emc_exit
);
349 MODULE_DESCRIPTION(DM_NAME
" EMC CX/AX/FC-family multipath");
350 MODULE_AUTHOR("Lars Marowsky-Bree <lmb@suse.de>");
351 MODULE_LICENSE("GPL");
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