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 | ||
24 | #include <scsi/scsi_dh.h> | |
25 | #include "../scsi_priv.h" | |
26 | ||
7c32c7a2 HR |
27 | struct scsi_dh_devinfo_list { |
28 | struct list_head node; | |
29 | char vendor[9]; | |
30 | char model[17]; | |
31 | struct scsi_device_handler *handler; | |
32 | }; | |
33 | ||
a6a8d9f8 CS |
34 | static DEFINE_SPINLOCK(list_lock); |
35 | static LIST_HEAD(scsi_dh_list); | |
7c32c7a2 | 36 | static LIST_HEAD(scsi_dh_dev_list); |
a6a8d9f8 CS |
37 | |
38 | static struct scsi_device_handler *get_device_handler(const char *name) | |
39 | { | |
40 | struct scsi_device_handler *tmp, *found = NULL; | |
41 | ||
42 | spin_lock(&list_lock); | |
43 | list_for_each_entry(tmp, &scsi_dh_list, list) { | |
765cbc6d | 44 | if (!strncmp(tmp->name, name, strlen(tmp->name))) { |
a6a8d9f8 CS |
45 | found = tmp; |
46 | break; | |
47 | } | |
48 | } | |
49 | spin_unlock(&list_lock); | |
50 | return found; | |
51 | } | |
52 | ||
7c32c7a2 HR |
53 | |
54 | static struct scsi_device_handler * | |
55 | scsi_dh_cache_lookup(struct scsi_device *sdev) | |
a6a8d9f8 | 56 | { |
7c32c7a2 HR |
57 | struct scsi_dh_devinfo_list *tmp; |
58 | struct scsi_device_handler *found_dh = NULL; | |
59 | ||
60 | spin_lock(&list_lock); | |
61 | list_for_each_entry(tmp, &scsi_dh_dev_list, node) { | |
62 | if (!strncmp(sdev->vendor, tmp->vendor, strlen(tmp->vendor)) && | |
63 | !strncmp(sdev->model, tmp->model, strlen(tmp->model))) { | |
64 | found_dh = tmp->handler; | |
65 | break; | |
765cbc6d HR |
66 | } |
67 | } | |
7c32c7a2 | 68 | spin_unlock(&list_lock); |
a6a8d9f8 | 69 | |
7c32c7a2 HR |
70 | return found_dh; |
71 | } | |
72 | ||
73 | static int scsi_dh_handler_lookup(struct scsi_device_handler *scsi_dh, | |
74 | struct scsi_device *sdev) | |
75 | { | |
76 | int i, found = 0; | |
77 | ||
78 | for(i = 0; scsi_dh->devlist[i].vendor; i++) { | |
79 | if (!strncmp(sdev->vendor, scsi_dh->devlist[i].vendor, | |
80 | strlen(scsi_dh->devlist[i].vendor)) && | |
81 | !strncmp(sdev->model, scsi_dh->devlist[i].model, | |
82 | strlen(scsi_dh->devlist[i].model))) { | |
83 | found = 1; | |
84 | break; | |
85 | } | |
86 | } | |
87 | return found; | |
88 | } | |
89 | ||
90 | /* | |
91 | * device_handler_match - Attach a device handler to a device | |
92 | * @scsi_dh - The device handler to match against or NULL | |
93 | * @sdev - SCSI device to be tested against @scsi_dh | |
94 | * | |
95 | * Tests @sdev against the device handler @scsi_dh or against | |
96 | * all registered device_handler if @scsi_dh == NULL. | |
97 | * Returns the found device handler or NULL if not found. | |
98 | */ | |
99 | static struct scsi_device_handler * | |
100 | device_handler_match(struct scsi_device_handler *scsi_dh, | |
101 | struct scsi_device *sdev) | |
102 | { | |
103 | struct scsi_device_handler *found_dh = NULL; | |
104 | struct scsi_dh_devinfo_list *tmp; | |
105 | ||
106 | found_dh = scsi_dh_cache_lookup(sdev); | |
107 | if (found_dh) | |
108 | return found_dh; | |
109 | ||
110 | if (scsi_dh) { | |
111 | if (scsi_dh_handler_lookup(scsi_dh, sdev)) | |
112 | found_dh = scsi_dh; | |
113 | } else { | |
114 | struct scsi_device_handler *tmp_dh; | |
115 | ||
116 | spin_lock(&list_lock); | |
117 | list_for_each_entry(tmp_dh, &scsi_dh_list, list) { | |
118 | if (scsi_dh_handler_lookup(tmp_dh, sdev)) | |
119 | found_dh = tmp_dh; | |
120 | } | |
121 | spin_unlock(&list_lock); | |
122 | } | |
123 | ||
124 | if (found_dh) { /* If device is found, add it to the cache */ | |
125 | tmp = kmalloc(sizeof(*tmp), GFP_KERNEL); | |
126 | if (tmp) { | |
127 | strncpy(tmp->vendor, sdev->vendor, 8); | |
128 | strncpy(tmp->model, sdev->model, 16); | |
129 | tmp->vendor[8] = '\0'; | |
130 | tmp->model[16] = '\0'; | |
131 | tmp->handler = found_dh; | |
132 | spin_lock(&list_lock); | |
133 | list_add(&tmp->node, &scsi_dh_dev_list); | |
134 | spin_unlock(&list_lock); | |
135 | } else { | |
136 | found_dh = NULL; | |
137 | } | |
138 | } | |
139 | ||
140 | return found_dh; | |
a6a8d9f8 CS |
141 | } |
142 | ||
143 | /* | |
765cbc6d HR |
144 | * scsi_dh_handler_attach - Attach a device handler to a device |
145 | * @sdev - SCSI device the device handler should attach to | |
146 | * @scsi_dh - The device handler to attach | |
147 | */ | |
148 | static int scsi_dh_handler_attach(struct scsi_device *sdev, | |
149 | struct scsi_device_handler *scsi_dh) | |
150 | { | |
151 | int err = 0; | |
152 | ||
153 | if (sdev->scsi_dh_data) { | |
154 | if (sdev->scsi_dh_data->scsi_dh != scsi_dh) | |
155 | err = -EBUSY; | |
6c10db72 CS |
156 | else |
157 | kref_get(&sdev->scsi_dh_data->kref); | |
158 | } else if (scsi_dh->attach) { | |
765cbc6d | 159 | err = scsi_dh->attach(sdev); |
6c10db72 CS |
160 | if (!err) { |
161 | kref_init(&sdev->scsi_dh_data->kref); | |
162 | sdev->scsi_dh_data->sdev = sdev; | |
163 | } | |
164 | } | |
765cbc6d HR |
165 | return err; |
166 | } | |
167 | ||
6c10db72 CS |
168 | static void __detach_handler (struct kref *kref) |
169 | { | |
170 | struct scsi_dh_data *scsi_dh_data = container_of(kref, struct scsi_dh_data, kref); | |
171 | scsi_dh_data->scsi_dh->detach(scsi_dh_data->sdev); | |
172 | } | |
173 | ||
765cbc6d HR |
174 | /* |
175 | * scsi_dh_handler_detach - Detach a device handler from a device | |
176 | * @sdev - SCSI device the device handler should be detached from | |
177 | * @scsi_dh - Device handler to be detached | |
a6a8d9f8 | 178 | * |
765cbc6d | 179 | * Detach from a device handler. If a device handler is specified, |
4c05ae52 | 180 | * only detach if the currently attached handler matches @scsi_dh. |
a6a8d9f8 | 181 | */ |
765cbc6d HR |
182 | static void scsi_dh_handler_detach(struct scsi_device *sdev, |
183 | struct scsi_device_handler *scsi_dh) | |
a6a8d9f8 | 184 | { |
765cbc6d HR |
185 | if (!sdev->scsi_dh_data) |
186 | return; | |
a6a8d9f8 | 187 | |
765cbc6d HR |
188 | if (scsi_dh && scsi_dh != sdev->scsi_dh_data->scsi_dh) |
189 | return; | |
a6a8d9f8 | 190 | |
765cbc6d HR |
191 | if (!scsi_dh) |
192 | scsi_dh = sdev->scsi_dh_data->scsi_dh; | |
193 | ||
194 | if (scsi_dh && scsi_dh->detach) | |
6c10db72 | 195 | kref_put(&sdev->scsi_dh_data->kref, __detach_handler); |
765cbc6d HR |
196 | } |
197 | ||
4c05ae52 HR |
198 | /* |
199 | * Functions for sysfs attribute 'dh_state' | |
200 | */ | |
201 | static ssize_t | |
202 | store_dh_state(struct device *dev, struct device_attribute *attr, | |
203 | const char *buf, size_t count) | |
204 | { | |
205 | struct scsi_device *sdev = to_scsi_device(dev); | |
206 | struct scsi_device_handler *scsi_dh; | |
207 | int err = -EINVAL; | |
208 | ||
209 | if (!sdev->scsi_dh_data) { | |
210 | /* | |
211 | * Attach to a device handler | |
212 | */ | |
213 | if (!(scsi_dh = get_device_handler(buf))) | |
214 | return err; | |
215 | err = scsi_dh_handler_attach(sdev, scsi_dh); | |
216 | } else { | |
217 | scsi_dh = sdev->scsi_dh_data->scsi_dh; | |
218 | if (!strncmp(buf, "detach", 6)) { | |
219 | /* | |
220 | * Detach from a device handler | |
221 | */ | |
222 | scsi_dh_handler_detach(sdev, scsi_dh); | |
223 | err = 0; | |
224 | } else if (!strncmp(buf, "activate", 8)) { | |
225 | /* | |
226 | * Activate a device handler | |
227 | */ | |
228 | if (scsi_dh->activate) | |
229 | err = scsi_dh->activate(sdev); | |
230 | else | |
231 | err = 0; | |
232 | } | |
233 | } | |
234 | ||
235 | return err<0?err:count; | |
236 | } | |
237 | ||
238 | static ssize_t | |
239 | show_dh_state(struct device *dev, struct device_attribute *attr, char *buf) | |
240 | { | |
241 | struct scsi_device *sdev = to_scsi_device(dev); | |
242 | ||
243 | if (!sdev->scsi_dh_data) | |
244 | return snprintf(buf, 20, "detached\n"); | |
245 | ||
246 | return snprintf(buf, 20, "%s\n", sdev->scsi_dh_data->scsi_dh->name); | |
247 | } | |
248 | ||
249 | static struct device_attribute scsi_dh_state_attr = | |
250 | __ATTR(dh_state, S_IRUGO | S_IWUSR, show_dh_state, | |
251 | store_dh_state); | |
252 | ||
253 | /* | |
254 | * scsi_dh_sysfs_attr_add - Callback for scsi_init_dh | |
255 | */ | |
256 | static int scsi_dh_sysfs_attr_add(struct device *dev, void *data) | |
257 | { | |
258 | struct scsi_device *sdev; | |
259 | int err; | |
260 | ||
261 | if (!scsi_is_sdev_device(dev)) | |
262 | return 0; | |
263 | ||
264 | sdev = to_scsi_device(dev); | |
265 | ||
266 | err = device_create_file(&sdev->sdev_gendev, | |
267 | &scsi_dh_state_attr); | |
268 | ||
269 | return 0; | |
270 | } | |
271 | ||
272 | /* | |
273 | * scsi_dh_sysfs_attr_remove - Callback for scsi_exit_dh | |
274 | */ | |
275 | static int scsi_dh_sysfs_attr_remove(struct device *dev, void *data) | |
276 | { | |
277 | struct scsi_device *sdev; | |
278 | ||
279 | if (!scsi_is_sdev_device(dev)) | |
280 | return 0; | |
281 | ||
282 | sdev = to_scsi_device(dev); | |
283 | ||
284 | device_remove_file(&sdev->sdev_gendev, | |
285 | &scsi_dh_state_attr); | |
286 | ||
287 | return 0; | |
288 | } | |
289 | ||
765cbc6d HR |
290 | /* |
291 | * scsi_dh_notifier - notifier chain callback | |
292 | */ | |
293 | static int scsi_dh_notifier(struct notifier_block *nb, | |
294 | unsigned long action, void *data) | |
295 | { | |
296 | struct device *dev = data; | |
297 | struct scsi_device *sdev; | |
298 | int err = 0; | |
7c32c7a2 | 299 | struct scsi_device_handler *devinfo = NULL; |
765cbc6d HR |
300 | |
301 | if (!scsi_is_sdev_device(dev)) | |
302 | return 0; | |
303 | ||
304 | sdev = to_scsi_device(dev); | |
a6a8d9f8 | 305 | |
765cbc6d | 306 | if (action == BUS_NOTIFY_ADD_DEVICE) { |
7c32c7a2 HR |
307 | devinfo = device_handler_match(NULL, sdev); |
308 | if (!devinfo) | |
309 | goto out; | |
310 | ||
765cbc6d | 311 | err = scsi_dh_handler_attach(sdev, devinfo); |
4c05ae52 HR |
312 | if (!err) |
313 | err = device_create_file(dev, &scsi_dh_state_attr); | |
765cbc6d | 314 | } else if (action == BUS_NOTIFY_DEL_DEVICE) { |
4c05ae52 | 315 | device_remove_file(dev, &scsi_dh_state_attr); |
765cbc6d HR |
316 | scsi_dh_handler_detach(sdev, NULL); |
317 | } | |
318 | out: | |
319 | return err; | |
a6a8d9f8 | 320 | } |
a6a8d9f8 | 321 | |
765cbc6d HR |
322 | /* |
323 | * scsi_dh_notifier_add - Callback for scsi_register_device_handler | |
324 | */ | |
325 | static int scsi_dh_notifier_add(struct device *dev, void *data) | |
326 | { | |
327 | struct scsi_device_handler *scsi_dh = data; | |
328 | struct scsi_device *sdev; | |
329 | ||
330 | if (!scsi_is_sdev_device(dev)) | |
331 | return 0; | |
332 | ||
333 | if (!get_device(dev)) | |
334 | return 0; | |
335 | ||
336 | sdev = to_scsi_device(dev); | |
337 | ||
338 | if (device_handler_match(scsi_dh, sdev)) | |
339 | scsi_dh_handler_attach(sdev, scsi_dh); | |
340 | ||
341 | put_device(dev); | |
342 | ||
343 | return 0; | |
344 | } | |
345 | ||
346 | /* | |
347 | * scsi_dh_notifier_remove - Callback for scsi_unregister_device_handler | |
348 | */ | |
a6a8d9f8 CS |
349 | static int scsi_dh_notifier_remove(struct device *dev, void *data) |
350 | { | |
351 | struct scsi_device_handler *scsi_dh = data; | |
765cbc6d HR |
352 | struct scsi_device *sdev; |
353 | ||
354 | if (!scsi_is_sdev_device(dev)) | |
355 | return 0; | |
356 | ||
357 | if (!get_device(dev)) | |
358 | return 0; | |
359 | ||
360 | sdev = to_scsi_device(dev); | |
361 | ||
362 | scsi_dh_handler_detach(sdev, scsi_dh); | |
363 | ||
364 | put_device(dev); | |
a6a8d9f8 | 365 | |
a6a8d9f8 CS |
366 | return 0; |
367 | } | |
368 | ||
765cbc6d HR |
369 | /* |
370 | * scsi_register_device_handler - register a device handler personality | |
371 | * module. | |
372 | * @scsi_dh - device handler to be registered. | |
373 | * | |
374 | * Returns 0 on success, -EBUSY if handler already registered. | |
375 | */ | |
376 | int scsi_register_device_handler(struct scsi_device_handler *scsi_dh) | |
377 | { | |
378 | if (get_device_handler(scsi_dh->name)) | |
379 | return -EBUSY; | |
380 | ||
381 | spin_lock(&list_lock); | |
382 | list_add(&scsi_dh->list, &scsi_dh_list); | |
383 | spin_unlock(&list_lock); | |
384 | bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh, scsi_dh_notifier_add); | |
385 | printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name); | |
386 | ||
387 | return SCSI_DH_OK; | |
388 | } | |
389 | EXPORT_SYMBOL_GPL(scsi_register_device_handler); | |
390 | ||
a6a8d9f8 CS |
391 | /* |
392 | * scsi_unregister_device_handler - register a device handler personality | |
393 | * module. | |
394 | * @scsi_dh - device handler to be unregistered. | |
395 | * | |
396 | * Returns 0 on success, -ENODEV if handler not registered. | |
397 | */ | |
398 | int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh) | |
399 | { | |
7c32c7a2 HR |
400 | struct scsi_dh_devinfo_list *tmp, *pos; |
401 | ||
765cbc6d HR |
402 | if (!get_device_handler(scsi_dh->name)) |
403 | return -ENODEV; | |
a6a8d9f8 CS |
404 | |
405 | bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh, | |
765cbc6d HR |
406 | scsi_dh_notifier_remove); |
407 | ||
a6a8d9f8 CS |
408 | spin_lock(&list_lock); |
409 | list_del(&scsi_dh->list); | |
7c32c7a2 HR |
410 | list_for_each_entry_safe(pos, tmp, &scsi_dh_dev_list, node) { |
411 | if (pos->handler == scsi_dh) { | |
412 | list_del(&pos->node); | |
413 | kfree(pos); | |
414 | } | |
415 | } | |
a6a8d9f8 | 416 | spin_unlock(&list_lock); |
765cbc6d | 417 | printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name); |
a6a8d9f8 | 418 | |
765cbc6d | 419 | return SCSI_DH_OK; |
a6a8d9f8 CS |
420 | } |
421 | EXPORT_SYMBOL_GPL(scsi_unregister_device_handler); | |
422 | ||
423 | /* | |
424 | * scsi_dh_activate - activate the path associated with the scsi_device | |
425 | * corresponding to the given request queue. | |
426 | * @q - Request queue that is associated with the scsi_device to be | |
427 | * activated. | |
428 | */ | |
429 | int scsi_dh_activate(struct request_queue *q) | |
430 | { | |
431 | int err = 0; | |
432 | unsigned long flags; | |
433 | struct scsi_device *sdev; | |
434 | struct scsi_device_handler *scsi_dh = NULL; | |
435 | ||
436 | spin_lock_irqsave(q->queue_lock, flags); | |
437 | sdev = q->queuedata; | |
438 | if (sdev && sdev->scsi_dh_data) | |
439 | scsi_dh = sdev->scsi_dh_data->scsi_dh; | |
440 | if (!scsi_dh || !get_device(&sdev->sdev_gendev)) | |
441 | err = SCSI_DH_NOSYS; | |
442 | spin_unlock_irqrestore(q->queue_lock, flags); | |
443 | ||
444 | if (err) | |
445 | return err; | |
446 | ||
447 | if (scsi_dh->activate) | |
448 | err = scsi_dh->activate(sdev); | |
449 | put_device(&sdev->sdev_gendev); | |
450 | return err; | |
451 | } | |
452 | EXPORT_SYMBOL_GPL(scsi_dh_activate); | |
453 | ||
454 | /* | |
455 | * scsi_dh_handler_exist - Return TRUE(1) if a device handler exists for | |
456 | * the given name. FALSE(0) otherwise. | |
457 | * @name - name of the device handler. | |
458 | */ | |
459 | int scsi_dh_handler_exist(const char *name) | |
460 | { | |
461 | return (get_device_handler(name) != NULL); | |
462 | } | |
463 | EXPORT_SYMBOL_GPL(scsi_dh_handler_exist); | |
464 | ||
ae11b1b3 HR |
465 | /* |
466 | * scsi_dh_handler_attach - Attach device handler | |
467 | * @sdev - sdev the handler should be attached to | |
468 | * @name - name of the handler to attach | |
469 | */ | |
470 | int scsi_dh_attach(struct request_queue *q, const char *name) | |
471 | { | |
472 | unsigned long flags; | |
473 | struct scsi_device *sdev; | |
474 | struct scsi_device_handler *scsi_dh; | |
475 | int err = 0; | |
476 | ||
477 | scsi_dh = get_device_handler(name); | |
478 | if (!scsi_dh) | |
479 | return -EINVAL; | |
480 | ||
481 | spin_lock_irqsave(q->queue_lock, flags); | |
482 | sdev = q->queuedata; | |
483 | if (!sdev || !get_device(&sdev->sdev_gendev)) | |
484 | err = -ENODEV; | |
485 | spin_unlock_irqrestore(q->queue_lock, flags); | |
486 | ||
487 | if (!err) { | |
488 | err = scsi_dh_handler_attach(sdev, scsi_dh); | |
ae11b1b3 HR |
489 | put_device(&sdev->sdev_gendev); |
490 | } | |
491 | return err; | |
492 | } | |
493 | EXPORT_SYMBOL_GPL(scsi_dh_attach); | |
494 | ||
495 | /* | |
496 | * scsi_dh_handler_detach - Detach device handler | |
497 | * @sdev - sdev the handler should be detached from | |
498 | * | |
499 | * This function will detach the device handler only | |
500 | * if the sdev is not part of the internal list, ie | |
501 | * if it has been attached manually. | |
502 | */ | |
503 | void scsi_dh_detach(struct request_queue *q) | |
504 | { | |
505 | unsigned long flags; | |
506 | struct scsi_device *sdev; | |
507 | struct scsi_device_handler *scsi_dh = NULL; | |
508 | ||
509 | spin_lock_irqsave(q->queue_lock, flags); | |
510 | sdev = q->queuedata; | |
511 | if (!sdev || !get_device(&sdev->sdev_gendev)) | |
512 | sdev = NULL; | |
513 | spin_unlock_irqrestore(q->queue_lock, flags); | |
514 | ||
515 | if (!sdev) | |
516 | return; | |
517 | ||
518 | if (sdev->scsi_dh_data) { | |
ae11b1b3 | 519 | scsi_dh = sdev->scsi_dh_data->scsi_dh; |
6c10db72 | 520 | scsi_dh_handler_detach(sdev, scsi_dh); |
ae11b1b3 HR |
521 | } |
522 | put_device(&sdev->sdev_gendev); | |
523 | } | |
524 | EXPORT_SYMBOL_GPL(scsi_dh_detach); | |
525 | ||
765cbc6d HR |
526 | static struct notifier_block scsi_dh_nb = { |
527 | .notifier_call = scsi_dh_notifier | |
528 | }; | |
529 | ||
530 | static int __init scsi_dh_init(void) | |
531 | { | |
532 | int r; | |
533 | ||
534 | r = bus_register_notifier(&scsi_bus_type, &scsi_dh_nb); | |
535 | ||
4c05ae52 HR |
536 | if (!r) |
537 | bus_for_each_dev(&scsi_bus_type, NULL, NULL, | |
538 | scsi_dh_sysfs_attr_add); | |
539 | ||
765cbc6d HR |
540 | return r; |
541 | } | |
542 | ||
543 | static void __exit scsi_dh_exit(void) | |
544 | { | |
4c05ae52 HR |
545 | bus_for_each_dev(&scsi_bus_type, NULL, NULL, |
546 | scsi_dh_sysfs_attr_remove); | |
765cbc6d HR |
547 | bus_unregister_notifier(&scsi_bus_type, &scsi_dh_nb); |
548 | } | |
549 | ||
550 | module_init(scsi_dh_init); | |
551 | module_exit(scsi_dh_exit); | |
552 | ||
a6a8d9f8 CS |
553 | MODULE_DESCRIPTION("SCSI device handler"); |
554 | MODULE_AUTHOR("Chandra Seetharaman <sekharan@us.ibm.com>"); | |
555 | MODULE_LICENSE("GPL"); |