Commit | Line | Data |
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a6a8d9f8 CS |
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 | ||
5a0e3ad6 | 24 | #include <linux/slab.h> |
acf3368f | 25 | #include <linux/module.h> |
a6a8d9f8 CS |
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 | static struct scsi_device_handler *get_device_handler(const char *name) | |
33 | { | |
34 | struct scsi_device_handler *tmp, *found = NULL; | |
35 | ||
36 | spin_lock(&list_lock); | |
37 | list_for_each_entry(tmp, &scsi_dh_list, list) { | |
765cbc6d | 38 | if (!strncmp(tmp->name, name, strlen(tmp->name))) { |
a6a8d9f8 CS |
39 | found = tmp; |
40 | break; | |
41 | } | |
42 | } | |
43 | spin_unlock(&list_lock); | |
44 | return found; | |
45 | } | |
46 | ||
6c3633d0 HR |
47 | /* |
48 | * device_handler_match_function - Match a device handler to a device | |
49 | * @sdev - SCSI device to be tested | |
50 | * | |
51 | * Tests @sdev against the match function of all registered device_handler. | |
52 | * Returns the found device handler or NULL if not found. | |
53 | */ | |
54 | static struct scsi_device_handler * | |
55 | device_handler_match_function(struct scsi_device *sdev) | |
56 | { | |
57 | struct scsi_device_handler *tmp_dh, *found_dh = NULL; | |
58 | ||
59 | spin_lock(&list_lock); | |
60 | list_for_each_entry(tmp_dh, &scsi_dh_list, list) { | |
61 | if (tmp_dh->match && tmp_dh->match(sdev)) { | |
62 | found_dh = tmp_dh; | |
63 | break; | |
64 | } | |
65 | } | |
66 | spin_unlock(&list_lock); | |
67 | return found_dh; | |
68 | } | |
69 | ||
7c32c7a2 HR |
70 | /* |
71 | * device_handler_match - Attach a device handler to a device | |
72 | * @scsi_dh - The device handler to match against or NULL | |
73 | * @sdev - SCSI device to be tested against @scsi_dh | |
74 | * | |
75 | * Tests @sdev against the device handler @scsi_dh or against | |
76 | * all registered device_handler if @scsi_dh == NULL. | |
77 | * Returns the found device handler or NULL if not found. | |
78 | */ | |
79 | static struct scsi_device_handler * | |
80 | device_handler_match(struct scsi_device_handler *scsi_dh, | |
81 | struct scsi_device *sdev) | |
82 | { | |
6c3633d0 | 83 | struct scsi_device_handler *found_dh; |
7c32c7a2 | 84 | |
6c3633d0 | 85 | found_dh = device_handler_match_function(sdev); |
7c32c7a2 | 86 | |
940d7faa PJ |
87 | if (scsi_dh && found_dh != scsi_dh) |
88 | found_dh = NULL; | |
7c32c7a2 HR |
89 | |
90 | return found_dh; | |
a6a8d9f8 CS |
91 | } |
92 | ||
93 | /* | |
765cbc6d HR |
94 | * scsi_dh_handler_attach - Attach a device handler to a device |
95 | * @sdev - SCSI device the device handler should attach to | |
96 | * @scsi_dh - The device handler to attach | |
97 | */ | |
98 | static int scsi_dh_handler_attach(struct scsi_device *sdev, | |
99 | struct scsi_device_handler *scsi_dh) | |
100 | { | |
101 | int err = 0; | |
102 | ||
103 | if (sdev->scsi_dh_data) { | |
104 | if (sdev->scsi_dh_data->scsi_dh != scsi_dh) | |
27c888f0 CH |
105 | return -EBUSY; |
106 | ||
107 | kref_get(&sdev->scsi_dh_data->kref); | |
108 | return 0; | |
109 | } | |
110 | ||
1f12ffa5 CH |
111 | if (!try_module_get(scsi_dh->module)) |
112 | return -EINVAL; | |
27c888f0 | 113 | |
1f12ffa5 CH |
114 | err = scsi_dh->attach(sdev); |
115 | if (err) { | |
116 | module_put(scsi_dh->module); | |
117 | return err; | |
6c10db72 | 118 | } |
1f12ffa5 CH |
119 | |
120 | kref_init(&sdev->scsi_dh_data->kref); | |
121 | sdev->scsi_dh_data->sdev = sdev; | |
765cbc6d HR |
122 | return err; |
123 | } | |
124 | ||
6c10db72 CS |
125 | static void __detach_handler (struct kref *kref) |
126 | { | |
27c888f0 CH |
127 | struct scsi_dh_data *scsi_dh_data = |
128 | container_of(kref, struct scsi_dh_data, kref); | |
129 | struct scsi_device_handler *scsi_dh = scsi_dh_data->scsi_dh; | |
130 | ||
131 | scsi_dh->detach(scsi_dh_data->sdev); | |
132 | module_put(scsi_dh->module); | |
6c10db72 CS |
133 | } |
134 | ||
765cbc6d HR |
135 | /* |
136 | * scsi_dh_handler_detach - Detach a device handler from a device | |
137 | * @sdev - SCSI device the device handler should be detached from | |
138 | * @scsi_dh - Device handler to be detached | |
a6a8d9f8 | 139 | * |
765cbc6d | 140 | * Detach from a device handler. If a device handler is specified, |
4c05ae52 | 141 | * only detach if the currently attached handler matches @scsi_dh. |
a6a8d9f8 | 142 | */ |
765cbc6d HR |
143 | static void scsi_dh_handler_detach(struct scsi_device *sdev, |
144 | struct scsi_device_handler *scsi_dh) | |
a6a8d9f8 | 145 | { |
765cbc6d HR |
146 | if (!sdev->scsi_dh_data) |
147 | return; | |
a6a8d9f8 | 148 | |
765cbc6d HR |
149 | if (scsi_dh && scsi_dh != sdev->scsi_dh_data->scsi_dh) |
150 | return; | |
a6a8d9f8 | 151 | |
765cbc6d HR |
152 | if (!scsi_dh) |
153 | scsi_dh = sdev->scsi_dh_data->scsi_dh; | |
154 | ||
1f12ffa5 | 155 | if (scsi_dh) |
6c10db72 | 156 | kref_put(&sdev->scsi_dh_data->kref, __detach_handler); |
765cbc6d HR |
157 | } |
158 | ||
4c05ae52 HR |
159 | /* |
160 | * Functions for sysfs attribute 'dh_state' | |
161 | */ | |
162 | static ssize_t | |
163 | store_dh_state(struct device *dev, struct device_attribute *attr, | |
164 | const char *buf, size_t count) | |
165 | { | |
166 | struct scsi_device *sdev = to_scsi_device(dev); | |
167 | struct scsi_device_handler *scsi_dh; | |
168 | int err = -EINVAL; | |
169 | ||
6bc8d2a0 HR |
170 | if (sdev->sdev_state == SDEV_CANCEL || |
171 | sdev->sdev_state == SDEV_DEL) | |
172 | return -ENODEV; | |
173 | ||
4c05ae52 HR |
174 | if (!sdev->scsi_dh_data) { |
175 | /* | |
176 | * Attach to a device handler | |
177 | */ | |
178 | if (!(scsi_dh = get_device_handler(buf))) | |
179 | return err; | |
180 | err = scsi_dh_handler_attach(sdev, scsi_dh); | |
181 | } else { | |
182 | scsi_dh = sdev->scsi_dh_data->scsi_dh; | |
183 | if (!strncmp(buf, "detach", 6)) { | |
184 | /* | |
185 | * Detach from a device handler | |
186 | */ | |
187 | scsi_dh_handler_detach(sdev, scsi_dh); | |
188 | err = 0; | |
189 | } else if (!strncmp(buf, "activate", 8)) { | |
190 | /* | |
191 | * Activate a device handler | |
192 | */ | |
193 | if (scsi_dh->activate) | |
3ae31f6a | 194 | err = scsi_dh->activate(sdev, NULL, NULL); |
4c05ae52 HR |
195 | else |
196 | err = 0; | |
197 | } | |
198 | } | |
199 | ||
200 | return err<0?err:count; | |
201 | } | |
202 | ||
203 | static ssize_t | |
204 | show_dh_state(struct device *dev, struct device_attribute *attr, char *buf) | |
205 | { | |
206 | struct scsi_device *sdev = to_scsi_device(dev); | |
207 | ||
208 | if (!sdev->scsi_dh_data) | |
209 | return snprintf(buf, 20, "detached\n"); | |
210 | ||
211 | return snprintf(buf, 20, "%s\n", sdev->scsi_dh_data->scsi_dh->name); | |
212 | } | |
213 | ||
214 | static struct device_attribute scsi_dh_state_attr = | |
215 | __ATTR(dh_state, S_IRUGO | S_IWUSR, show_dh_state, | |
216 | store_dh_state); | |
217 | ||
218 | /* | |
219 | * scsi_dh_sysfs_attr_add - Callback for scsi_init_dh | |
220 | */ | |
221 | static int scsi_dh_sysfs_attr_add(struct device *dev, void *data) | |
222 | { | |
223 | struct scsi_device *sdev; | |
224 | int err; | |
225 | ||
226 | if (!scsi_is_sdev_device(dev)) | |
227 | return 0; | |
228 | ||
229 | sdev = to_scsi_device(dev); | |
230 | ||
231 | err = device_create_file(&sdev->sdev_gendev, | |
232 | &scsi_dh_state_attr); | |
233 | ||
234 | return 0; | |
235 | } | |
236 | ||
237 | /* | |
238 | * scsi_dh_sysfs_attr_remove - Callback for scsi_exit_dh | |
239 | */ | |
240 | static int scsi_dh_sysfs_attr_remove(struct device *dev, void *data) | |
241 | { | |
242 | struct scsi_device *sdev; | |
243 | ||
244 | if (!scsi_is_sdev_device(dev)) | |
245 | return 0; | |
246 | ||
247 | sdev = to_scsi_device(dev); | |
248 | ||
249 | device_remove_file(&sdev->sdev_gendev, | |
250 | &scsi_dh_state_attr); | |
251 | ||
252 | return 0; | |
253 | } | |
254 | ||
765cbc6d HR |
255 | /* |
256 | * scsi_dh_notifier - notifier chain callback | |
257 | */ | |
258 | static int scsi_dh_notifier(struct notifier_block *nb, | |
259 | unsigned long action, void *data) | |
260 | { | |
261 | struct device *dev = data; | |
262 | struct scsi_device *sdev; | |
263 | int err = 0; | |
7c32c7a2 | 264 | struct scsi_device_handler *devinfo = NULL; |
765cbc6d HR |
265 | |
266 | if (!scsi_is_sdev_device(dev)) | |
267 | return 0; | |
268 | ||
269 | sdev = to_scsi_device(dev); | |
a6a8d9f8 | 270 | |
765cbc6d | 271 | if (action == BUS_NOTIFY_ADD_DEVICE) { |
5917290c CS |
272 | err = device_create_file(dev, &scsi_dh_state_attr); |
273 | /* don't care about err */ | |
7c32c7a2 | 274 | devinfo = device_handler_match(NULL, sdev); |
5917290c CS |
275 | if (devinfo) |
276 | err = scsi_dh_handler_attach(sdev, devinfo); | |
765cbc6d | 277 | } else if (action == BUS_NOTIFY_DEL_DEVICE) { |
4c05ae52 | 278 | device_remove_file(dev, &scsi_dh_state_attr); |
765cbc6d HR |
279 | scsi_dh_handler_detach(sdev, NULL); |
280 | } | |
765cbc6d | 281 | return err; |
a6a8d9f8 | 282 | } |
a6a8d9f8 | 283 | |
765cbc6d HR |
284 | /* |
285 | * scsi_dh_notifier_add - Callback for scsi_register_device_handler | |
286 | */ | |
287 | static int scsi_dh_notifier_add(struct device *dev, void *data) | |
288 | { | |
289 | struct scsi_device_handler *scsi_dh = data; | |
290 | struct scsi_device *sdev; | |
291 | ||
292 | if (!scsi_is_sdev_device(dev)) | |
293 | return 0; | |
294 | ||
295 | if (!get_device(dev)) | |
296 | return 0; | |
297 | ||
298 | sdev = to_scsi_device(dev); | |
299 | ||
300 | if (device_handler_match(scsi_dh, sdev)) | |
301 | scsi_dh_handler_attach(sdev, scsi_dh); | |
302 | ||
303 | put_device(dev); | |
304 | ||
305 | return 0; | |
306 | } | |
307 | ||
308 | /* | |
309 | * scsi_dh_notifier_remove - Callback for scsi_unregister_device_handler | |
310 | */ | |
a6a8d9f8 CS |
311 | static int scsi_dh_notifier_remove(struct device *dev, void *data) |
312 | { | |
313 | struct scsi_device_handler *scsi_dh = data; | |
765cbc6d HR |
314 | struct scsi_device *sdev; |
315 | ||
316 | if (!scsi_is_sdev_device(dev)) | |
317 | return 0; | |
318 | ||
319 | if (!get_device(dev)) | |
320 | return 0; | |
321 | ||
322 | sdev = to_scsi_device(dev); | |
323 | ||
324 | scsi_dh_handler_detach(sdev, scsi_dh); | |
325 | ||
326 | put_device(dev); | |
a6a8d9f8 | 327 | |
a6a8d9f8 CS |
328 | return 0; |
329 | } | |
330 | ||
765cbc6d HR |
331 | /* |
332 | * scsi_register_device_handler - register a device handler personality | |
333 | * module. | |
334 | * @scsi_dh - device handler to be registered. | |
335 | * | |
336 | * Returns 0 on success, -EBUSY if handler already registered. | |
337 | */ | |
338 | int scsi_register_device_handler(struct scsi_device_handler *scsi_dh) | |
339 | { | |
940d7faa | 340 | |
765cbc6d HR |
341 | if (get_device_handler(scsi_dh->name)) |
342 | return -EBUSY; | |
343 | ||
1f12ffa5 CH |
344 | if (!scsi_dh->attach || !scsi_dh->detach) |
345 | return -EINVAL; | |
346 | ||
765cbc6d HR |
347 | spin_lock(&list_lock); |
348 | list_add(&scsi_dh->list, &scsi_dh_list); | |
349 | spin_unlock(&list_lock); | |
940d7faa | 350 | |
765cbc6d HR |
351 | bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh, scsi_dh_notifier_add); |
352 | printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name); | |
353 | ||
354 | return SCSI_DH_OK; | |
355 | } | |
356 | EXPORT_SYMBOL_GPL(scsi_register_device_handler); | |
357 | ||
a6a8d9f8 CS |
358 | /* |
359 | * scsi_unregister_device_handler - register a device handler personality | |
360 | * module. | |
361 | * @scsi_dh - device handler to be unregistered. | |
362 | * | |
363 | * Returns 0 on success, -ENODEV if handler not registered. | |
364 | */ | |
365 | int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh) | |
366 | { | |
7c32c7a2 | 367 | |
765cbc6d HR |
368 | if (!get_device_handler(scsi_dh->name)) |
369 | return -ENODEV; | |
a6a8d9f8 CS |
370 | |
371 | bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh, | |
765cbc6d HR |
372 | scsi_dh_notifier_remove); |
373 | ||
a6a8d9f8 CS |
374 | spin_lock(&list_lock); |
375 | list_del(&scsi_dh->list); | |
376 | spin_unlock(&list_lock); | |
765cbc6d | 377 | printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name); |
a6a8d9f8 | 378 | |
765cbc6d | 379 | return SCSI_DH_OK; |
a6a8d9f8 CS |
380 | } |
381 | EXPORT_SYMBOL_GPL(scsi_unregister_device_handler); | |
382 | ||
383 | /* | |
384 | * scsi_dh_activate - activate the path associated with the scsi_device | |
385 | * corresponding to the given request queue. | |
3ae31f6a CS |
386 | * Returns immediately without waiting for activation to be completed. |
387 | * @q - Request queue that is associated with the scsi_device to be | |
388 | * activated. | |
389 | * @fn - Function to be called upon completion of the activation. | |
390 | * Function fn is called with data (below) and the error code. | |
391 | * Function fn may be called from the same calling context. So, | |
392 | * do not hold the lock in the caller which may be needed in fn. | |
393 | * @data - data passed to the function fn upon completion. | |
394 | * | |
a6a8d9f8 | 395 | */ |
3ae31f6a | 396 | int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data) |
a6a8d9f8 CS |
397 | { |
398 | int err = 0; | |
399 | unsigned long flags; | |
400 | struct scsi_device *sdev; | |
401 | struct scsi_device_handler *scsi_dh = NULL; | |
0b839357 | 402 | struct device *dev = NULL; |
a6a8d9f8 CS |
403 | |
404 | spin_lock_irqsave(q->queue_lock, flags); | |
405 | sdev = q->queuedata; | |
a18a920c MB |
406 | if (!sdev) { |
407 | spin_unlock_irqrestore(q->queue_lock, flags); | |
408 | err = SCSI_DH_NOSYS; | |
409 | if (fn) | |
410 | fn(data, err); | |
411 | return err; | |
412 | } | |
413 | ||
414 | if (sdev->scsi_dh_data) | |
a6a8d9f8 | 415 | scsi_dh = sdev->scsi_dh_data->scsi_dh; |
0b839357 MS |
416 | dev = get_device(&sdev->sdev_gendev); |
417 | if (!scsi_dh || !dev || | |
db422318 MH |
418 | sdev->sdev_state == SDEV_CANCEL || |
419 | sdev->sdev_state == SDEV_DEL) | |
a6a8d9f8 | 420 | err = SCSI_DH_NOSYS; |
db422318 MH |
421 | if (sdev->sdev_state == SDEV_OFFLINE) |
422 | err = SCSI_DH_DEV_OFFLINED; | |
a6a8d9f8 CS |
423 | spin_unlock_irqrestore(q->queue_lock, flags); |
424 | ||
db422318 MH |
425 | if (err) { |
426 | if (fn) | |
427 | fn(data, err); | |
0b839357 | 428 | goto out; |
db422318 | 429 | } |
a6a8d9f8 CS |
430 | |
431 | if (scsi_dh->activate) | |
3ae31f6a | 432 | err = scsi_dh->activate(sdev, fn, data); |
0b839357 MS |
433 | out: |
434 | put_device(dev); | |
a6a8d9f8 CS |
435 | return err; |
436 | } | |
437 | EXPORT_SYMBOL_GPL(scsi_dh_activate); | |
438 | ||
18ee70c9 CS |
439 | /* |
440 | * scsi_dh_set_params - set the parameters for the device as per the | |
441 | * string specified in params. | |
442 | * @q - Request queue that is associated with the scsi_device for | |
443 | * which the parameters to be set. | |
444 | * @params - parameters in the following format | |
445 | * "no_of_params\0param1\0param2\0param3\0...\0" | |
446 | * for example, string for 2 parameters with value 10 and 21 | |
447 | * is specified as "2\010\021\0". | |
448 | */ | |
449 | int scsi_dh_set_params(struct request_queue *q, const char *params) | |
450 | { | |
451 | int err = -SCSI_DH_NOSYS; | |
452 | unsigned long flags; | |
453 | struct scsi_device *sdev; | |
454 | struct scsi_device_handler *scsi_dh = NULL; | |
455 | ||
456 | spin_lock_irqsave(q->queue_lock, flags); | |
457 | sdev = q->queuedata; | |
458 | if (sdev && sdev->scsi_dh_data) | |
459 | scsi_dh = sdev->scsi_dh_data->scsi_dh; | |
460 | if (scsi_dh && scsi_dh->set_params && get_device(&sdev->sdev_gendev)) | |
461 | err = 0; | |
462 | spin_unlock_irqrestore(q->queue_lock, flags); | |
463 | ||
464 | if (err) | |
465 | return err; | |
466 | err = scsi_dh->set_params(sdev, params); | |
467 | put_device(&sdev->sdev_gendev); | |
468 | return err; | |
469 | } | |
470 | EXPORT_SYMBOL_GPL(scsi_dh_set_params); | |
471 | ||
a6a8d9f8 CS |
472 | /* |
473 | * scsi_dh_handler_exist - Return TRUE(1) if a device handler exists for | |
474 | * the given name. FALSE(0) otherwise. | |
475 | * @name - name of the device handler. | |
476 | */ | |
477 | int scsi_dh_handler_exist(const char *name) | |
478 | { | |
479 | return (get_device_handler(name) != NULL); | |
480 | } | |
481 | EXPORT_SYMBOL_GPL(scsi_dh_handler_exist); | |
482 | ||
ae11b1b3 | 483 | /* |
2a9ab40f | 484 | * scsi_dh_attach - Attach device handler |
7e8a74b1 MS |
485 | * @q - Request queue that is associated with the scsi_device |
486 | * the handler should be attached to | |
ae11b1b3 HR |
487 | * @name - name of the handler to attach |
488 | */ | |
489 | int scsi_dh_attach(struct request_queue *q, const char *name) | |
490 | { | |
491 | unsigned long flags; | |
492 | struct scsi_device *sdev; | |
493 | struct scsi_device_handler *scsi_dh; | |
494 | int err = 0; | |
495 | ||
496 | scsi_dh = get_device_handler(name); | |
497 | if (!scsi_dh) | |
498 | return -EINVAL; | |
499 | ||
500 | spin_lock_irqsave(q->queue_lock, flags); | |
501 | sdev = q->queuedata; | |
502 | if (!sdev || !get_device(&sdev->sdev_gendev)) | |
503 | err = -ENODEV; | |
504 | spin_unlock_irqrestore(q->queue_lock, flags); | |
505 | ||
506 | if (!err) { | |
507 | err = scsi_dh_handler_attach(sdev, scsi_dh); | |
ae11b1b3 HR |
508 | put_device(&sdev->sdev_gendev); |
509 | } | |
510 | return err; | |
511 | } | |
512 | EXPORT_SYMBOL_GPL(scsi_dh_attach); | |
513 | ||
514 | /* | |
2a9ab40f | 515 | * scsi_dh_detach - Detach device handler |
7e8a74b1 MS |
516 | * @q - Request queue that is associated with the scsi_device |
517 | * the handler should be detached from | |
ae11b1b3 HR |
518 | * |
519 | * This function will detach the device handler only | |
520 | * if the sdev is not part of the internal list, ie | |
521 | * if it has been attached manually. | |
522 | */ | |
523 | void scsi_dh_detach(struct request_queue *q) | |
524 | { | |
525 | unsigned long flags; | |
526 | struct scsi_device *sdev; | |
527 | struct scsi_device_handler *scsi_dh = NULL; | |
528 | ||
529 | spin_lock_irqsave(q->queue_lock, flags); | |
530 | sdev = q->queuedata; | |
531 | if (!sdev || !get_device(&sdev->sdev_gendev)) | |
532 | sdev = NULL; | |
533 | spin_unlock_irqrestore(q->queue_lock, flags); | |
534 | ||
535 | if (!sdev) | |
536 | return; | |
537 | ||
538 | if (sdev->scsi_dh_data) { | |
ae11b1b3 | 539 | scsi_dh = sdev->scsi_dh_data->scsi_dh; |
6c10db72 | 540 | scsi_dh_handler_detach(sdev, scsi_dh); |
ae11b1b3 HR |
541 | } |
542 | put_device(&sdev->sdev_gendev); | |
543 | } | |
544 | EXPORT_SYMBOL_GPL(scsi_dh_detach); | |
545 | ||
7e8a74b1 MS |
546 | /* |
547 | * scsi_dh_attached_handler_name - Get attached device handler's name | |
548 | * @q - Request queue that is associated with the scsi_device | |
549 | * that may have a device handler attached | |
550 | * @gfp - the GFP mask used in the kmalloc() call when allocating memory | |
551 | * | |
552 | * Returns name of attached handler, NULL if no handler is attached. | |
553 | * Caller must take care to free the returned string. | |
554 | */ | |
555 | const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp) | |
556 | { | |
557 | unsigned long flags; | |
558 | struct scsi_device *sdev; | |
559 | const char *handler_name = NULL; | |
560 | ||
561 | spin_lock_irqsave(q->queue_lock, flags); | |
562 | sdev = q->queuedata; | |
563 | if (!sdev || !get_device(&sdev->sdev_gendev)) | |
564 | sdev = NULL; | |
565 | spin_unlock_irqrestore(q->queue_lock, flags); | |
566 | ||
567 | if (!sdev) | |
568 | return NULL; | |
569 | ||
570 | if (sdev->scsi_dh_data) | |
571 | handler_name = kstrdup(sdev->scsi_dh_data->scsi_dh->name, gfp); | |
572 | ||
573 | put_device(&sdev->sdev_gendev); | |
574 | return handler_name; | |
575 | } | |
576 | EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name); | |
577 | ||
765cbc6d HR |
578 | static struct notifier_block scsi_dh_nb = { |
579 | .notifier_call = scsi_dh_notifier | |
580 | }; | |
581 | ||
582 | static int __init scsi_dh_init(void) | |
583 | { | |
584 | int r; | |
585 | ||
586 | r = bus_register_notifier(&scsi_bus_type, &scsi_dh_nb); | |
587 | ||
4c05ae52 HR |
588 | if (!r) |
589 | bus_for_each_dev(&scsi_bus_type, NULL, NULL, | |
590 | scsi_dh_sysfs_attr_add); | |
591 | ||
765cbc6d HR |
592 | return r; |
593 | } | |
594 | ||
595 | static void __exit scsi_dh_exit(void) | |
596 | { | |
4c05ae52 HR |
597 | bus_for_each_dev(&scsi_bus_type, NULL, NULL, |
598 | scsi_dh_sysfs_attr_remove); | |
765cbc6d HR |
599 | bus_unregister_notifier(&scsi_bus_type, &scsi_dh_nb); |
600 | } | |
601 | ||
602 | module_init(scsi_dh_init); | |
603 | module_exit(scsi_dh_exit); | |
604 | ||
a6a8d9f8 CS |
605 | MODULE_DESCRIPTION("SCSI device handler"); |
606 | MODULE_AUTHOR("Chandra Seetharaman <sekharan@us.ibm.com>"); | |
607 | MODULE_LICENSE("GPL"); |