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1/*
2 * SCSI device handler infrastruture.
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License as published by the
6 * Free Software Foundation; either version 2 of the License, or (at your
7 * option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright IBM Corporation, 2007
19 * Authors:
20 * Chandra Seetharaman <sekharan@us.ibm.com>
21 * Mike Anderson <andmike@linux.vnet.ibm.com>
22 */
23
24#include <linux/slab.h>
25#include <linux/module.h>
26#include <scsi/scsi_dh.h>
27#include "scsi_priv.h"
28
29static DEFINE_SPINLOCK(list_lock);
30static LIST_HEAD(scsi_dh_list);
31
32struct scsi_dh_blist {
33 const char *vendor;
34 const char *model;
35 const char *driver;
36};
37
38static const struct scsi_dh_blist scsi_dh_blist[] = {
39 {"DGC", "RAID", "emc" },
40 {"DGC", "DISK", "emc" },
41 {"DGC", "VRAID", "emc" },
42
43 {"COMPAQ", "MSA1000 VOLUME", "hp_sw" },
44 {"COMPAQ", "HSV110", "hp_sw" },
45 {"HP", "HSV100", "hp_sw"},
46 {"DEC", "HSG80", "hp_sw"},
47
48 {"IBM", "1722", "rdac", },
49 {"IBM", "1724", "rdac", },
50 {"IBM", "1726", "rdac", },
51 {"IBM", "1742", "rdac", },
52 {"IBM", "1745", "rdac", },
53 {"IBM", "1746", "rdac", },
54 {"IBM", "1813", "rdac", },
55 {"IBM", "1814", "rdac", },
56 {"IBM", "1815", "rdac", },
57 {"IBM", "1818", "rdac", },
58 {"IBM", "3526", "rdac", },
59 {"IBM", "3542", "rdac", },
60 {"IBM", "3552", "rdac", },
61 {"SGI", "TP9", "rdac", },
62 {"SGI", "IS", "rdac", },
63 {"STK", "OPENstorage", "rdac", },
64 {"STK", "FLEXLINE 380", "rdac", },
65 {"STK", "BladeCtlr", "rdac", },
66 {"SUN", "CSM", "rdac", },
67 {"SUN", "LCSM100", "rdac", },
68 {"SUN", "STK6580_6780", "rdac", },
69 {"SUN", "SUN_6180", "rdac", },
70 {"SUN", "ArrayStorage", "rdac", },
71 {"DELL", "MD3", "rdac", },
72 {"NETAPP", "INF-01-00", "rdac", },
73 {"LSI", "INF-01-00", "rdac", },
74 {"ENGENIO", "INF-01-00", "rdac", },
75 {NULL, NULL, NULL },
76};
77
78static const char *
79scsi_dh_find_driver(struct scsi_device *sdev)
80{
81 const struct scsi_dh_blist *b;
82
83 if (scsi_device_tpgs(sdev))
84 return "alua";
85
86 for (b = scsi_dh_blist; b->vendor; b++) {
87 if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
88 !strncmp(sdev->model, b->model, strlen(b->model))) {
89 return b->driver;
90 }
91 }
92 return NULL;
93}
94
95
96static struct scsi_device_handler *__scsi_dh_lookup(const char *name)
97{
98 struct scsi_device_handler *tmp, *found = NULL;
99
100 spin_lock(&list_lock);
101 list_for_each_entry(tmp, &scsi_dh_list, list) {
102 if (!strncmp(tmp->name, name, strlen(tmp->name))) {
103 found = tmp;
104 break;
105 }
106 }
107 spin_unlock(&list_lock);
108 return found;
109}
110
111static struct scsi_device_handler *scsi_dh_lookup(const char *name)
112{
113 struct scsi_device_handler *dh;
114
115 if (!name || strlen(name) == 0)
116 return NULL;
117
118 dh = __scsi_dh_lookup(name);
119 if (!dh) {
120 request_module("scsi_dh_%s", name);
121 dh = __scsi_dh_lookup(name);
122 }
123
124 return dh;
125}
126
127/*
128 * scsi_dh_handler_attach - Attach a device handler to a device
129 * @sdev - SCSI device the device handler should attach to
130 * @scsi_dh - The device handler to attach
131 */
132static int scsi_dh_handler_attach(struct scsi_device *sdev,
133 struct scsi_device_handler *scsi_dh)
134{
135 int error, ret = 0;
136
137 if (!try_module_get(scsi_dh->module))
138 return -EINVAL;
139
140 error = scsi_dh->attach(sdev);
141 if (error != SCSI_DH_OK) {
142 switch (error) {
143 case SCSI_DH_NOMEM:
144 ret = -ENOMEM;
145 break;
146 case SCSI_DH_RES_TEMP_UNAVAIL:
147 ret = -EAGAIN;
148 break;
149 case SCSI_DH_DEV_UNSUPP:
150 case SCSI_DH_NOSYS:
151 ret = -ENODEV;
152 break;
153 default:
154 ret = -EINVAL;
155 break;
156 }
157 if (ret != -ENODEV)
158 sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
159 scsi_dh->name, error);
160 module_put(scsi_dh->module);
161 } else
162 sdev->handler = scsi_dh;
163
164 return ret;
165}
166
167/*
168 * scsi_dh_handler_detach - Detach a device handler from a device
169 * @sdev - SCSI device the device handler should be detached from
170 */
171static void scsi_dh_handler_detach(struct scsi_device *sdev)
172{
173 sdev->handler->detach(sdev);
174 sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
175 module_put(sdev->handler->module);
176}
177
178void scsi_dh_add_device(struct scsi_device *sdev)
179{
180 struct scsi_device_handler *devinfo = NULL;
181 const char *drv;
182
183 drv = scsi_dh_find_driver(sdev);
184 if (drv)
185 devinfo = __scsi_dh_lookup(drv);
186 /*
187 * device_handler is optional, so ignore errors
188 * from scsi_dh_handler_attach()
189 */
190 if (devinfo)
191 (void)scsi_dh_handler_attach(sdev, devinfo);
192}
193
194void scsi_dh_release_device(struct scsi_device *sdev)
195{
196 if (sdev->handler)
197 scsi_dh_handler_detach(sdev);
198}
199
200/*
201 * scsi_register_device_handler - register a device handler personality
202 * module.
203 * @scsi_dh - device handler to be registered.
204 *
205 * Returns 0 on success, -EBUSY if handler already registered.
206 */
207int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
208{
209 if (__scsi_dh_lookup(scsi_dh->name))
210 return -EBUSY;
211
212 if (!scsi_dh->attach || !scsi_dh->detach)
213 return -EINVAL;
214
215 spin_lock(&list_lock);
216 list_add(&scsi_dh->list, &scsi_dh_list);
217 spin_unlock(&list_lock);
218
219 printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
220
221 return SCSI_DH_OK;
222}
223EXPORT_SYMBOL_GPL(scsi_register_device_handler);
224
225/*
226 * scsi_unregister_device_handler - register a device handler personality
227 * module.
228 * @scsi_dh - device handler to be unregistered.
229 *
230 * Returns 0 on success, -ENODEV if handler not registered.
231 */
232int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
233{
234 if (!__scsi_dh_lookup(scsi_dh->name))
235 return -ENODEV;
236
237 spin_lock(&list_lock);
238 list_del(&scsi_dh->list);
239 spin_unlock(&list_lock);
240 printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
241
242 return SCSI_DH_OK;
243}
244EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
245
246/*
247 * scsi_dh_activate - activate the path associated with the scsi_device
248 * corresponding to the given request queue.
249 * Returns immediately without waiting for activation to be completed.
250 * @q - Request queue that is associated with the scsi_device to be
251 * activated.
252 * @fn - Function to be called upon completion of the activation.
253 * Function fn is called with data (below) and the error code.
254 * Function fn may be called from the same calling context. So,
255 * do not hold the lock in the caller which may be needed in fn.
256 * @data - data passed to the function fn upon completion.
257 *
258 */
259int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
260{
261 struct scsi_device *sdev;
262 int err = SCSI_DH_NOSYS;
263
264 sdev = scsi_device_from_queue(q);
265 if (!sdev) {
266 if (fn)
267 fn(data, err);
268 return err;
269 }
270
271 if (!sdev->handler)
272 goto out_fn;
273 err = SCSI_DH_NOTCONN;
274 if (sdev->sdev_state == SDEV_CANCEL ||
275 sdev->sdev_state == SDEV_DEL)
276 goto out_fn;
277
278 err = SCSI_DH_DEV_OFFLINED;
279 if (sdev->sdev_state == SDEV_OFFLINE)
280 goto out_fn;
281
282 if (sdev->handler->activate)
283 err = sdev->handler->activate(sdev, fn, data);
284
285out_put_device:
286 put_device(&sdev->sdev_gendev);
287 return err;
288
289out_fn:
290 if (fn)
291 fn(data, err);
292 goto out_put_device;
293}
294EXPORT_SYMBOL_GPL(scsi_dh_activate);
295
296/*
297 * scsi_dh_set_params - set the parameters for the device as per the
298 * string specified in params.
299 * @q - Request queue that is associated with the scsi_device for
300 * which the parameters to be set.
301 * @params - parameters in the following format
302 * "no_of_params\0param1\0param2\0param3\0...\0"
303 * for example, string for 2 parameters with value 10 and 21
304 * is specified as "2\010\021\0".
305 */
306int scsi_dh_set_params(struct request_queue *q, const char *params)
307{
308 struct scsi_device *sdev;
309 int err = -SCSI_DH_NOSYS;
310
311 sdev = scsi_device_from_queue(q);
312 if (!sdev)
313 return err;
314
315 if (sdev->handler && sdev->handler->set_params)
316 err = sdev->handler->set_params(sdev, params);
317 put_device(&sdev->sdev_gendev);
318 return err;
319}
320EXPORT_SYMBOL_GPL(scsi_dh_set_params);
321
322/*
323 * scsi_dh_attach - Attach device handler
324 * @q - Request queue that is associated with the scsi_device
325 * the handler should be attached to
326 * @name - name of the handler to attach
327 */
328int scsi_dh_attach(struct request_queue *q, const char *name)
329{
330 struct scsi_device *sdev;
331 struct scsi_device_handler *scsi_dh;
332 int err = 0;
333
334 sdev = scsi_device_from_queue(q);
335 if (!sdev)
336 return -ENODEV;
337
338 scsi_dh = scsi_dh_lookup(name);
339 if (!scsi_dh) {
340 err = -EINVAL;
341 goto out_put_device;
342 }
343
344 if (sdev->handler) {
345 if (sdev->handler != scsi_dh)
346 err = -EBUSY;
347 goto out_put_device;
348 }
349
350 err = scsi_dh_handler_attach(sdev, scsi_dh);
351
352out_put_device:
353 put_device(&sdev->sdev_gendev);
354 return err;
355}
356EXPORT_SYMBOL_GPL(scsi_dh_attach);
357
358/*
359 * scsi_dh_attached_handler_name - Get attached device handler's name
360 * @q - Request queue that is associated with the scsi_device
361 * that may have a device handler attached
362 * @gfp - the GFP mask used in the kmalloc() call when allocating memory
363 *
364 * Returns name of attached handler, NULL if no handler is attached.
365 * Caller must take care to free the returned string.
366 */
367const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
368{
369 struct scsi_device *sdev;
370 const char *handler_name = NULL;
371
372 sdev = scsi_device_from_queue(q);
373 if (!sdev)
374 return NULL;
375
376 if (sdev->handler)
377 handler_name = kstrdup(sdev->handler->name, gfp);
378 put_device(&sdev->sdev_gendev);
379 return handler_name;
380}
381EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);