blob: 204bf42c94493575518bc72e3536ddc9b94c27de [file] [log] [blame]
Dave Wysochanski16ebbf32007-10-19 22:47:54 +01001/*
2 * Copyright (C) 2005 Mike Christie, All rights reserved.
3 * Copyright (C) 2007 Red Hat, Inc. All rights reserved.
4 * Authors: Mike Christie
5 * Dave Wysochanski
6 *
7 * This file is released under the GPL.
8 *
9 * This module implements the specific path activation code for
10 * HP StorageWorks and FSC FibreCat Asymmetric (Active/Passive)
11 * storage arrays.
12 * These storage arrays have controller-based failover, not
13 * LUN-based failover. However, LUN-based failover is the design
14 * of dm-multipath. Thus, this module is written for LUN-based failover.
15 */
16#include <linux/blkdev.h>
17#include <linux/list.h>
18#include <linux/types.h>
19#include <scsi/scsi.h>
20#include <scsi/scsi_cmnd.h>
Dave Wysochanskife97e2a2007-10-19 22:47:55 +010021#include <scsi/scsi_dbg.h>
Dave Wysochanski16ebbf32007-10-19 22:47:54 +010022
23#include "dm.h"
24#include "dm-hw-handler.h"
25
26#define DM_MSG_PREFIX "multipath hp-sw"
27#define DM_HP_HWH_NAME "hp-sw"
Dave Wysochanskife97e2a2007-10-19 22:47:55 +010028#define DM_HP_HWH_VER "1.0.0"
Dave Wysochanski16ebbf32007-10-19 22:47:54 +010029
30struct hp_sw_context {
31 unsigned char sense[SCSI_SENSE_BUFFERSIZE];
32};
33
34/*
Dave Wysochanskife97e2a2007-10-19 22:47:55 +010035 * hp_sw_error_is_retryable - Is an HP-specific check condition retryable?
36 * @req: path activation request
37 *
38 * Examine error codes of request and determine whether the error is retryable.
39 * Some error codes are already retried by scsi-ml (see
40 * scsi_decide_disposition), but some HP specific codes are not.
41 * The intent of this routine is to supply the logic for the HP specific
42 * check conditions.
43 *
44 * Returns:
45 * 1 - command completed with retryable error
46 * 0 - command completed with non-retryable error
47 *
48 * Possible optimizations
49 * 1. More hardware-specific error codes
50 */
51static int hp_sw_error_is_retryable(struct request *req)
52{
53 /*
54 * NOT_READY is known to be retryable
55 * For now we just dump out the sense data and call it retryable
56 */
57 if (status_byte(req->errors) == CHECK_CONDITION)
58 __scsi_print_sense(DM_HP_HWH_NAME, req->sense, req->sense_len);
59
60 /*
61 * At this point we don't have complete information about all the error
62 * codes from this hardware, so we are just conservative and retry
63 * when in doubt.
64 */
65 return 1;
66}
67
68/*
Dave Wysochanski16ebbf32007-10-19 22:47:54 +010069 * hp_sw_end_io - Completion handler for HP path activation.
70 * @req: path activation request
71 * @error: scsi-ml error
72 *
73 * Check sense data, free request structure, and notify dm that
74 * pg initialization has completed.
75 *
76 * Context: scsi-ml softirq
77 *
Dave Wysochanski16ebbf32007-10-19 22:47:54 +010078 */
79static void hp_sw_end_io(struct request *req, int error)
80{
81 struct dm_path *path = req->end_io_data;
82 unsigned err_flags = 0;
83
Dave Wysochanskife97e2a2007-10-19 22:47:55 +010084 if (!error) {
Dave Wysochanski16ebbf32007-10-19 22:47:54 +010085 DMDEBUG("%s path activation command - success",
86 path->dev->name);
Dave Wysochanskife97e2a2007-10-19 22:47:55 +010087 goto out;
Dave Wysochanski16ebbf32007-10-19 22:47:54 +010088 }
89
Dave Wysochanskife97e2a2007-10-19 22:47:55 +010090 if (hp_sw_error_is_retryable(req)) {
91 DMDEBUG("%s path activation command - retry",
92 path->dev->name);
93 err_flags = MP_RETRY;
94 goto out;
95 }
96
97 DMWARN("%s path activation fail - error=0x%x",
98 path->dev->name, error);
99 err_flags = MP_FAIL_PATH;
100
101out:
Dave Wysochanski16ebbf32007-10-19 22:47:54 +0100102 req->end_io_data = NULL;
103 __blk_put_request(req->q, req);
104 dm_pg_init_complete(path, err_flags);
105}
106
107/*
108 * hp_sw_get_request - Allocate an HP specific path activation request
109 * @path: path on which request will be sent (needed for request queue)
110 *
111 * The START command is used for path activation request.
112 * These arrays are controller-based failover, not LUN based.
113 * One START command issued to a single path will fail over all
114 * LUNs for the same controller.
115 *
116 * Possible optimizations
117 * 1. Make timeout configurable
118 * 2. Preallocate request
119 */
120static struct request *hp_sw_get_request(struct dm_path *path)
121{
122 struct request *req;
123 struct block_device *bdev = path->dev->bdev;
124 struct request_queue *q = bdev_get_queue(bdev);
125 struct hp_sw_context *h = path->hwhcontext;
126
127 req = blk_get_request(q, WRITE, GFP_NOIO);
128 if (!req)
129 goto out;
130
131 req->timeout = 60 * HZ;
132
133 req->errors = 0;
134 req->cmd_type = REQ_TYPE_BLOCK_PC;
135 req->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE;
136 req->end_io_data = path;
137 req->sense = h->sense;
138 memset(req->sense, 0, SCSI_SENSE_BUFFERSIZE);
139
140 memset(&req->cmd, 0, BLK_MAX_CDB);
141 req->cmd[0] = START_STOP;
142 req->cmd[4] = 1;
143 req->cmd_len = COMMAND_SIZE(req->cmd[0]);
144
145out:
146 return req;
147}
148
149/*
150 * hp_sw_pg_init - HP path activation implementation.
151 * @hwh: hardware handler specific data
152 * @bypassed: unused; is the path group bypassed? (see dm-mpath.c)
153 * @path: path to send initialization command
154 *
155 * Send an HP-specific path activation command on 'path'.
156 * Do not try to optimize in any way, just send the activation command.
157 * More than one path activation command may be sent to the same controller.
158 * This seems to work fine for basic failover support.
159 *
160 * Possible optimizations
161 * 1. Detect an in-progress activation request and avoid submitting another one
162 * 2. Model the controller and only send a single activation request at a time
163 * 3. Determine the state of a path before sending an activation request
164 *
165 * Context: kmpathd (see process_queued_ios() in dm-mpath.c)
166 */
167static void hp_sw_pg_init(struct hw_handler *hwh, unsigned bypassed,
168 struct dm_path *path)
169{
170 struct request *req;
171 struct hp_sw_context *h;
172
173 path->hwhcontext = hwh->context;
174 h = hwh->context;
175
176 req = hp_sw_get_request(path);
177 if (!req) {
178 DMERR("%s path activation command - allocation fail",
179 path->dev->name);
Dave Wysochanskife97e2a2007-10-19 22:47:55 +0100180 goto retry;
Dave Wysochanski16ebbf32007-10-19 22:47:54 +0100181 }
182
183 DMDEBUG("%s path activation command - sent", path->dev->name);
184
185 blk_execute_rq_nowait(req->q, NULL, req, 1, hp_sw_end_io);
186 return;
187
Dave Wysochanskife97e2a2007-10-19 22:47:55 +0100188retry:
189 dm_pg_init_complete(path, MP_RETRY);
Dave Wysochanski16ebbf32007-10-19 22:47:54 +0100190}
191
192static int hp_sw_create(struct hw_handler *hwh, unsigned argc, char **argv)
193{
194 struct hp_sw_context *h;
195
196 h = kmalloc(sizeof(*h), GFP_KERNEL);
197 if (!h)
198 return -ENOMEM;
199
200 hwh->context = h;
201
202 return 0;
203}
204
205static void hp_sw_destroy(struct hw_handler *hwh)
206{
207 struct hp_sw_context *h = hwh->context;
208
209 kfree(h);
210}
211
212static struct hw_handler_type hp_sw_hwh = {
213 .name = DM_HP_HWH_NAME,
214 .module = THIS_MODULE,
215 .create = hp_sw_create,
216 .destroy = hp_sw_destroy,
217 .pg_init = hp_sw_pg_init,
218};
219
220static int __init hp_sw_init(void)
221{
222 int r;
223
224 r = dm_register_hw_handler(&hp_sw_hwh);
225 if (r < 0)
226 DMERR("register failed %d", r);
227 else
228 DMINFO("version " DM_HP_HWH_VER " loaded");
229
230 return r;
231}
232
233static void __exit hp_sw_exit(void)
234{
235 int r;
236
237 r = dm_unregister_hw_handler(&hp_sw_hwh);
238 if (r < 0)
239 DMERR("unregister failed %d", r);
240}
241
242module_init(hp_sw_init);
243module_exit(hp_sw_exit);
244
245MODULE_DESCRIPTION("DM Multipath HP StorageWorks / FSC FibreCat (A/P) support");
246MODULE_AUTHOR("Mike Christie, Dave Wysochanski <dm-devel@redhat.com>");
247MODULE_LICENSE("GPL");
248MODULE_VERSION(DM_HP_HWH_VER);