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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 | ||
29 | static DEFINE_SPINLOCK(list_lock); | |
30 | static LIST_HEAD(scsi_dh_list); | |
31 | ||
32 | struct scsi_dh_blist { | |
33 | const char *vendor; | |
34 | const char *model; | |
35 | const char *driver; | |
36 | }; | |
37 | ||
38 | static const struct scsi_dh_blist scsi_dh_blist[] = { | |
39 | {"DGC", "RAID", "clariion" }, | |
40 | {"DGC", "DISK", "clariion" }, | |
41 | {"DGC", "VRAID", "clariion" }, | |
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 | {"SGI", "TP9", "rdac", }, | |
60 | {"SGI", "IS", "rdac", }, | |
61 | {"STK", "OPENstorage D280", "rdac", }, | |
62 | {"STK", "FLEXLINE 380", "rdac", }, | |
63 | {"SUN", "CSM", "rdac", }, | |
64 | {"SUN", "LCSM100", "rdac", }, | |
65 | {"SUN", "STK6580_6780", "rdac", }, | |
66 | {"SUN", "SUN_6180", "rdac", }, | |
67 | {"SUN", "ArrayStorage", "rdac", }, | |
68 | {"DELL", "MD3", "rdac", }, | |
69 | {"NETAPP", "INF-01-00", "rdac", }, | |
70 | {"LSI", "INF-01-00", "rdac", }, | |
71 | {"ENGENIO", "INF-01-00", "rdac", }, | |
72 | {NULL, NULL, NULL }, | |
73 | }; | |
74 | ||
75 | static const char * | |
76 | scsi_dh_find_driver(struct scsi_device *sdev) | |
77 | { | |
78 | const struct scsi_dh_blist *b; | |
79 | ||
80 | if (scsi_device_tpgs(sdev)) | |
81 | return "alua"; | |
82 | ||
83 | for (b = scsi_dh_blist; b->vendor; b++) { | |
84 | if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) && | |
85 | !strncmp(sdev->model, b->model, strlen(b->model))) { | |
86 | return b->driver; | |
87 | } | |
88 | } | |
89 | return NULL; | |
90 | } | |
91 | ||
92 | ||
93 | static struct scsi_device_handler *__scsi_dh_lookup(const char *name) | |
94 | { | |
95 | struct scsi_device_handler *tmp, *found = NULL; | |
96 | ||
97 | spin_lock(&list_lock); | |
98 | list_for_each_entry(tmp, &scsi_dh_list, list) { | |
99 | if (!strncmp(tmp->name, name, strlen(tmp->name))) { | |
100 | found = tmp; | |
101 | break; | |
102 | } | |
103 | } | |
104 | spin_unlock(&list_lock); | |
105 | return found; | |
106 | } | |
107 | ||
108 | static struct scsi_device_handler *scsi_dh_lookup(const char *name) | |
109 | { | |
110 | struct scsi_device_handler *dh; | |
111 | ||
112 | dh = __scsi_dh_lookup(name); | |
113 | if (!dh) { | |
114 | request_module("scsi_dh_%s", name); | |
115 | dh = __scsi_dh_lookup(name); | |
116 | } | |
117 | ||
118 | return dh; | |
119 | } | |
120 | ||
121 | /* | |
122 | * scsi_dh_handler_attach - Attach a device handler to a device | |
123 | * @sdev - SCSI device the device handler should attach to | |
124 | * @scsi_dh - The device handler to attach | |
125 | */ | |
126 | static int scsi_dh_handler_attach(struct scsi_device *sdev, | |
127 | struct scsi_device_handler *scsi_dh) | |
128 | { | |
129 | int error; | |
130 | ||
131 | if (!try_module_get(scsi_dh->module)) | |
132 | return -EINVAL; | |
133 | ||
134 | error = scsi_dh->attach(sdev); | |
135 | if (error) { | |
136 | sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n", | |
137 | scsi_dh->name, error); | |
138 | module_put(scsi_dh->module); | |
139 | } else | |
140 | sdev->handler = scsi_dh; | |
141 | ||
142 | return error; | |
143 | } | |
144 | ||
145 | /* | |
146 | * scsi_dh_handler_detach - Detach a device handler from a device | |
147 | * @sdev - SCSI device the device handler should be detached from | |
148 | */ | |
149 | static void scsi_dh_handler_detach(struct scsi_device *sdev) | |
150 | { | |
151 | sdev->handler->detach(sdev); | |
152 | sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name); | |
153 | module_put(sdev->handler->module); | |
154 | } | |
155 | ||
156 | /* | |
157 | * Functions for sysfs attribute 'dh_state' | |
158 | */ | |
159 | static ssize_t | |
160 | store_dh_state(struct device *dev, struct device_attribute *attr, | |
161 | const char *buf, size_t count) | |
162 | { | |
163 | struct scsi_device *sdev = to_scsi_device(dev); | |
164 | struct scsi_device_handler *scsi_dh; | |
165 | int err = -EINVAL; | |
166 | ||
167 | if (sdev->sdev_state == SDEV_CANCEL || | |
168 | sdev->sdev_state == SDEV_DEL) | |
169 | return -ENODEV; | |
170 | ||
171 | if (!sdev->handler) { | |
172 | /* | |
173 | * Attach to a device handler | |
174 | */ | |
175 | scsi_dh = scsi_dh_lookup(buf); | |
176 | if (!scsi_dh) | |
177 | return err; | |
178 | err = scsi_dh_handler_attach(sdev, scsi_dh); | |
179 | } else { | |
180 | if (!strncmp(buf, "detach", 6)) { | |
181 | /* | |
182 | * Detach from a device handler | |
183 | */ | |
184 | sdev_printk(KERN_WARNING, sdev, | |
185 | "can't detach handler %s.\n", | |
186 | sdev->handler->name); | |
187 | err = -EINVAL; | |
188 | } else if (!strncmp(buf, "activate", 8)) { | |
189 | /* | |
190 | * Activate a device handler | |
191 | */ | |
192 | if (sdev->handler->activate) | |
193 | err = sdev->handler->activate(sdev, NULL, NULL); | |
194 | else | |
195 | err = 0; | |
196 | } | |
197 | } | |
198 | ||
199 | return err<0?err:count; | |
200 | } | |
201 | ||
202 | static ssize_t | |
203 | show_dh_state(struct device *dev, struct device_attribute *attr, char *buf) | |
204 | { | |
205 | struct scsi_device *sdev = to_scsi_device(dev); | |
206 | ||
207 | if (!sdev->handler) | |
208 | return snprintf(buf, 20, "detached\n"); | |
209 | ||
210 | return snprintf(buf, 20, "%s\n", sdev->handler->name); | |
211 | } | |
212 | ||
213 | static struct device_attribute scsi_dh_state_attr = | |
214 | __ATTR(dh_state, S_IRUGO | S_IWUSR, show_dh_state, | |
215 | store_dh_state); | |
216 | ||
217 | int scsi_dh_add_device(struct scsi_device *sdev) | |
218 | { | |
219 | struct scsi_device_handler *devinfo = NULL; | |
220 | const char *drv; | |
221 | int err; | |
222 | ||
223 | err = device_create_file(&sdev->sdev_gendev, &scsi_dh_state_attr); | |
224 | if (err) | |
225 | return err; | |
226 | ||
227 | drv = scsi_dh_find_driver(sdev); | |
228 | if (drv) | |
229 | devinfo = scsi_dh_lookup(drv); | |
230 | if (devinfo) | |
231 | err = scsi_dh_handler_attach(sdev, devinfo); | |
232 | return err; | |
233 | } | |
234 | ||
235 | void scsi_dh_remove_device(struct scsi_device *sdev) | |
236 | { | |
237 | if (sdev->handler) | |
238 | scsi_dh_handler_detach(sdev); | |
239 | device_remove_file(&sdev->sdev_gendev, &scsi_dh_state_attr); | |
240 | } | |
241 | ||
242 | /* | |
243 | * scsi_register_device_handler - register a device handler personality | |
244 | * module. | |
245 | * @scsi_dh - device handler to be registered. | |
246 | * | |
247 | * Returns 0 on success, -EBUSY if handler already registered. | |
248 | */ | |
249 | int scsi_register_device_handler(struct scsi_device_handler *scsi_dh) | |
250 | { | |
251 | if (__scsi_dh_lookup(scsi_dh->name)) | |
252 | return -EBUSY; | |
253 | ||
254 | if (!scsi_dh->attach || !scsi_dh->detach) | |
255 | return -EINVAL; | |
256 | ||
257 | spin_lock(&list_lock); | |
258 | list_add(&scsi_dh->list, &scsi_dh_list); | |
259 | spin_unlock(&list_lock); | |
260 | ||
261 | printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name); | |
262 | ||
263 | return SCSI_DH_OK; | |
264 | } | |
265 | EXPORT_SYMBOL_GPL(scsi_register_device_handler); | |
266 | ||
267 | /* | |
268 | * scsi_unregister_device_handler - register a device handler personality | |
269 | * module. | |
270 | * @scsi_dh - device handler to be unregistered. | |
271 | * | |
272 | * Returns 0 on success, -ENODEV if handler not registered. | |
273 | */ | |
274 | int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh) | |
275 | { | |
276 | if (!__scsi_dh_lookup(scsi_dh->name)) | |
277 | return -ENODEV; | |
278 | ||
279 | spin_lock(&list_lock); | |
280 | list_del(&scsi_dh->list); | |
281 | spin_unlock(&list_lock); | |
282 | printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name); | |
283 | ||
284 | return SCSI_DH_OK; | |
285 | } | |
286 | EXPORT_SYMBOL_GPL(scsi_unregister_device_handler); | |
287 | ||
288 | static struct scsi_device *get_sdev_from_queue(struct request_queue *q) | |
289 | { | |
290 | struct scsi_device *sdev; | |
291 | unsigned long flags; | |
292 | ||
293 | spin_lock_irqsave(q->queue_lock, flags); | |
294 | sdev = q->queuedata; | |
295 | if (!sdev || !get_device(&sdev->sdev_gendev)) | |
296 | sdev = NULL; | |
297 | spin_unlock_irqrestore(q->queue_lock, flags); | |
298 | ||
299 | return sdev; | |
300 | } | |
301 | ||
302 | /* | |
303 | * scsi_dh_activate - activate the path associated with the scsi_device | |
304 | * corresponding to the given request queue. | |
305 | * Returns immediately without waiting for activation to be completed. | |
306 | * @q - Request queue that is associated with the scsi_device to be | |
307 | * activated. | |
308 | * @fn - Function to be called upon completion of the activation. | |
309 | * Function fn is called with data (below) and the error code. | |
310 | * Function fn may be called from the same calling context. So, | |
311 | * do not hold the lock in the caller which may be needed in fn. | |
312 | * @data - data passed to the function fn upon completion. | |
313 | * | |
314 | */ | |
315 | int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data) | |
316 | { | |
317 | struct scsi_device *sdev; | |
318 | int err = SCSI_DH_NOSYS; | |
319 | ||
320 | sdev = get_sdev_from_queue(q); | |
321 | if (!sdev) { | |
322 | if (fn) | |
323 | fn(data, err); | |
324 | return err; | |
325 | } | |
326 | ||
327 | if (!sdev->handler) | |
328 | goto out_fn; | |
329 | err = SCSI_DH_NOTCONN; | |
330 | if (sdev->sdev_state == SDEV_CANCEL || | |
331 | sdev->sdev_state == SDEV_DEL) | |
332 | goto out_fn; | |
333 | ||
334 | err = SCSI_DH_DEV_OFFLINED; | |
335 | if (sdev->sdev_state == SDEV_OFFLINE) | |
336 | goto out_fn; | |
337 | ||
338 | if (sdev->handler->activate) | |
339 | err = sdev->handler->activate(sdev, fn, data); | |
340 | ||
341 | out_put_device: | |
342 | put_device(&sdev->sdev_gendev); | |
343 | return err; | |
344 | ||
345 | out_fn: | |
346 | if (fn) | |
347 | fn(data, err); | |
348 | goto out_put_device; | |
349 | } | |
350 | EXPORT_SYMBOL_GPL(scsi_dh_activate); | |
351 | ||
352 | /* | |
353 | * scsi_dh_set_params - set the parameters for the device as per the | |
354 | * string specified in params. | |
355 | * @q - Request queue that is associated with the scsi_device for | |
356 | * which the parameters to be set. | |
357 | * @params - parameters in the following format | |
358 | * "no_of_params\0param1\0param2\0param3\0...\0" | |
359 | * for example, string for 2 parameters with value 10 and 21 | |
360 | * is specified as "2\010\021\0". | |
361 | */ | |
362 | int scsi_dh_set_params(struct request_queue *q, const char *params) | |
363 | { | |
364 | struct scsi_device *sdev; | |
365 | int err = -SCSI_DH_NOSYS; | |
366 | ||
367 | sdev = get_sdev_from_queue(q); | |
368 | if (!sdev) | |
369 | return err; | |
370 | ||
371 | if (sdev->handler && sdev->handler->set_params) | |
372 | err = sdev->handler->set_params(sdev, params); | |
373 | put_device(&sdev->sdev_gendev); | |
374 | return err; | |
375 | } | |
376 | EXPORT_SYMBOL_GPL(scsi_dh_set_params); | |
377 | ||
378 | /* | |
379 | * scsi_dh_attach - Attach device handler | |
380 | * @q - Request queue that is associated with the scsi_device | |
381 | * the handler should be attached to | |
382 | * @name - name of the handler to attach | |
383 | */ | |
384 | int scsi_dh_attach(struct request_queue *q, const char *name) | |
385 | { | |
386 | struct scsi_device *sdev; | |
387 | struct scsi_device_handler *scsi_dh; | |
388 | int err = 0; | |
389 | ||
390 | sdev = get_sdev_from_queue(q); | |
391 | if (!sdev) | |
392 | return -ENODEV; | |
393 | ||
394 | scsi_dh = scsi_dh_lookup(name); | |
395 | if (!scsi_dh) { | |
396 | err = -EINVAL; | |
397 | goto out_put_device; | |
398 | } | |
399 | ||
400 | if (sdev->handler) { | |
401 | if (sdev->handler != scsi_dh) | |
402 | err = -EBUSY; | |
403 | goto out_put_device; | |
404 | } | |
405 | ||
406 | err = scsi_dh_handler_attach(sdev, scsi_dh); | |
407 | ||
408 | out_put_device: | |
409 | put_device(&sdev->sdev_gendev); | |
410 | return err; | |
411 | } | |
412 | EXPORT_SYMBOL_GPL(scsi_dh_attach); | |
413 | ||
414 | /* | |
415 | * scsi_dh_attached_handler_name - Get attached device handler's name | |
416 | * @q - Request queue that is associated with the scsi_device | |
417 | * that may have a device handler attached | |
418 | * @gfp - the GFP mask used in the kmalloc() call when allocating memory | |
419 | * | |
420 | * Returns name of attached handler, NULL if no handler is attached. | |
421 | * Caller must take care to free the returned string. | |
422 | */ | |
423 | const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp) | |
424 | { | |
425 | struct scsi_device *sdev; | |
426 | const char *handler_name = NULL; | |
427 | ||
428 | sdev = get_sdev_from_queue(q); | |
429 | if (!sdev) | |
430 | return NULL; | |
431 | ||
432 | if (sdev->handler) | |
433 | handler_name = kstrdup(sdev->handler->name, gfp); | |
434 | put_device(&sdev->sdev_gendev); | |
435 | return handler_name; | |
436 | } | |
437 | EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name); |