Commit | Line | Data |
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1da177e4 | 1 | /* |
65a8de36 | 2 | * $Id: mtd_blkdevs.c,v 1.26 2005/07/29 19:42:04 tpoynor Exp $ |
1da177e4 LT |
3 | * |
4 | * (C) 2003 David Woodhouse <dwmw2@infradead.org> | |
5 | * | |
6 | * Interface to Linux 2.5 block layer for MTD 'translation layers'. | |
7 | * | |
8 | */ | |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/list.h> | |
14 | #include <linux/fs.h> | |
15 | #include <linux/mtd/blktrans.h> | |
16 | #include <linux/mtd/mtd.h> | |
17 | #include <linux/blkdev.h> | |
18 | #include <linux/blkpg.h> | |
19 | #include <linux/spinlock.h> | |
20 | #include <linux/hdreg.h> | |
21 | #include <linux/init.h> | |
22 | #include <asm/semaphore.h> | |
23 | #include <asm/uaccess.h> | |
1da177e4 LT |
24 | |
25 | static LIST_HEAD(blktrans_majors); | |
26 | ||
27 | extern struct semaphore mtd_table_mutex; | |
28 | extern struct mtd_info *mtd_table[]; | |
29 | ||
30 | struct mtd_blkcore_priv { | |
31 | struct completion thread_dead; | |
32 | int exiting; | |
33 | wait_queue_head_t thread_wq; | |
34 | struct request_queue *rq; | |
35 | spinlock_t queue_lock; | |
36 | }; | |
37 | ||
38 | static int do_blktrans_request(struct mtd_blktrans_ops *tr, | |
39 | struct mtd_blktrans_dev *dev, | |
40 | struct request *req) | |
41 | { | |
42 | unsigned long block, nsect; | |
43 | char *buf; | |
44 | ||
45 | block = req->sector; | |
46 | nsect = req->current_nr_sectors; | |
47 | buf = req->buffer; | |
48 | ||
49 | if (!(req->flags & REQ_CMD)) | |
50 | return 0; | |
51 | ||
52 | if (block + nsect > get_capacity(req->rq_disk)) | |
53 | return 0; | |
54 | ||
55 | switch(rq_data_dir(req)) { | |
56 | case READ: | |
57 | for (; nsect > 0; nsect--, block++, buf += 512) | |
58 | if (tr->readsect(dev, block, buf)) | |
59 | return 0; | |
60 | return 1; | |
61 | ||
62 | case WRITE: | |
63 | if (!tr->writesect) | |
64 | return 0; | |
65 | ||
66 | for (; nsect > 0; nsect--, block++, buf += 512) | |
67 | if (tr->writesect(dev, block, buf)) | |
68 | return 0; | |
69 | return 1; | |
70 | ||
71 | default: | |
72 | printk(KERN_NOTICE "Unknown request %ld\n", rq_data_dir(req)); | |
73 | return 0; | |
74 | } | |
75 | } | |
76 | ||
77 | static int mtd_blktrans_thread(void *arg) | |
78 | { | |
79 | struct mtd_blktrans_ops *tr = arg; | |
80 | struct request_queue *rq = tr->blkcore_priv->rq; | |
81 | ||
82 | /* we might get involved when memory gets low, so use PF_MEMALLOC */ | |
83 | current->flags |= PF_MEMALLOC | PF_NOFREEZE; | |
84 | ||
85 | daemonize("%sd", tr->name); | |
86 | ||
87 | /* daemonize() doesn't do this for us since some kernel threads | |
88 | actually want to deal with signals. We can't just call | |
89 | exit_sighand() since that'll cause an oops when we finally | |
90 | do exit. */ | |
91 | spin_lock_irq(¤t->sighand->siglock); | |
92 | sigfillset(¤t->blocked); | |
93 | recalc_sigpending(); | |
94 | spin_unlock_irq(¤t->sighand->siglock); | |
95 | ||
96 | spin_lock_irq(rq->queue_lock); | |
97 | ||
98 | while (!tr->blkcore_priv->exiting) { | |
99 | struct request *req; | |
100 | struct mtd_blktrans_dev *dev; | |
101 | int res = 0; | |
102 | DECLARE_WAITQUEUE(wait, current); | |
103 | ||
104 | req = elv_next_request(rq); | |
105 | ||
106 | if (!req) { | |
107 | add_wait_queue(&tr->blkcore_priv->thread_wq, &wait); | |
108 | set_current_state(TASK_INTERRUPTIBLE); | |
109 | ||
110 | spin_unlock_irq(rq->queue_lock); | |
111 | ||
112 | schedule(); | |
113 | remove_wait_queue(&tr->blkcore_priv->thread_wq, &wait); | |
114 | ||
115 | spin_lock_irq(rq->queue_lock); | |
116 | ||
117 | continue; | |
118 | } | |
119 | ||
120 | dev = req->rq_disk->private_data; | |
121 | tr = dev->tr; | |
122 | ||
123 | spin_unlock_irq(rq->queue_lock); | |
124 | ||
125 | down(&dev->sem); | |
126 | res = do_blktrans_request(tr, dev, req); | |
127 | up(&dev->sem); | |
128 | ||
129 | spin_lock_irq(rq->queue_lock); | |
130 | ||
131 | end_request(req, res); | |
132 | } | |
133 | spin_unlock_irq(rq->queue_lock); | |
134 | ||
135 | complete_and_exit(&tr->blkcore_priv->thread_dead, 0); | |
136 | } | |
137 | ||
138 | static void mtd_blktrans_request(struct request_queue *rq) | |
139 | { | |
140 | struct mtd_blktrans_ops *tr = rq->queuedata; | |
141 | wake_up(&tr->blkcore_priv->thread_wq); | |
142 | } | |
143 | ||
144 | ||
145 | static int blktrans_open(struct inode *i, struct file *f) | |
146 | { | |
147 | struct mtd_blktrans_dev *dev; | |
148 | struct mtd_blktrans_ops *tr; | |
149 | int ret = -ENODEV; | |
150 | ||
151 | dev = i->i_bdev->bd_disk->private_data; | |
152 | tr = dev->tr; | |
153 | ||
154 | if (!try_module_get(dev->mtd->owner)) | |
155 | goto out; | |
156 | ||
157 | if (!try_module_get(tr->owner)) | |
158 | goto out_tr; | |
159 | ||
160 | /* FIXME: Locking. A hot pluggable device can go away | |
161 | (del_mtd_device can be called for it) without its module | |
162 | being unloaded. */ | |
163 | dev->mtd->usecount++; | |
164 | ||
165 | ret = 0; | |
166 | if (tr->open && (ret = tr->open(dev))) { | |
167 | dev->mtd->usecount--; | |
168 | module_put(dev->mtd->owner); | |
169 | out_tr: | |
170 | module_put(tr->owner); | |
171 | } | |
172 | out: | |
173 | return ret; | |
174 | } | |
175 | ||
176 | static int blktrans_release(struct inode *i, struct file *f) | |
177 | { | |
178 | struct mtd_blktrans_dev *dev; | |
179 | struct mtd_blktrans_ops *tr; | |
180 | int ret = 0; | |
181 | ||
182 | dev = i->i_bdev->bd_disk->private_data; | |
183 | tr = dev->tr; | |
184 | ||
185 | if (tr->release) | |
186 | ret = tr->release(dev); | |
187 | ||
188 | if (!ret) { | |
189 | dev->mtd->usecount--; | |
190 | module_put(dev->mtd->owner); | |
191 | module_put(tr->owner); | |
192 | } | |
193 | ||
194 | return ret; | |
195 | } | |
196 | ||
197 | ||
198 | static int blktrans_ioctl(struct inode *inode, struct file *file, | |
199 | unsigned int cmd, unsigned long arg) | |
200 | { | |
201 | struct mtd_blktrans_dev *dev = inode->i_bdev->bd_disk->private_data; | |
202 | struct mtd_blktrans_ops *tr = dev->tr; | |
203 | ||
204 | switch (cmd) { | |
205 | case BLKFLSBUF: | |
206 | if (tr->flush) | |
207 | return tr->flush(dev); | |
208 | /* The core code did the work, we had nothing to do. */ | |
209 | return 0; | |
210 | ||
211 | case HDIO_GETGEO: | |
212 | if (tr->getgeo) { | |
213 | struct hd_geometry g; | |
214 | int ret; | |
215 | ||
216 | memset(&g, 0, sizeof(g)); | |
217 | ret = tr->getgeo(dev, &g); | |
218 | if (ret) | |
219 | return ret; | |
220 | ||
221 | g.start = get_start_sect(inode->i_bdev); | |
222 | if (copy_to_user((void __user *)arg, &g, sizeof(g))) | |
223 | return -EFAULT; | |
224 | return 0; | |
225 | } /* else */ | |
226 | default: | |
227 | return -ENOTTY; | |
228 | } | |
229 | } | |
230 | ||
231 | struct block_device_operations mtd_blktrans_ops = { | |
232 | .owner = THIS_MODULE, | |
233 | .open = blktrans_open, | |
234 | .release = blktrans_release, | |
235 | .ioctl = blktrans_ioctl, | |
236 | }; | |
237 | ||
238 | int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) | |
239 | { | |
240 | struct mtd_blktrans_ops *tr = new->tr; | |
241 | struct list_head *this; | |
242 | int last_devnum = -1; | |
243 | struct gendisk *gd; | |
244 | ||
245 | if (!down_trylock(&mtd_table_mutex)) { | |
246 | up(&mtd_table_mutex); | |
247 | BUG(); | |
248 | } | |
249 | ||
250 | list_for_each(this, &tr->devs) { | |
251 | struct mtd_blktrans_dev *d = list_entry(this, struct mtd_blktrans_dev, list); | |
252 | if (new->devnum == -1) { | |
253 | /* Use first free number */ | |
254 | if (d->devnum != last_devnum+1) { | |
255 | /* Found a free devnum. Plug it in here */ | |
256 | new->devnum = last_devnum+1; | |
257 | list_add_tail(&new->list, &d->list); | |
258 | goto added; | |
259 | } | |
260 | } else if (d->devnum == new->devnum) { | |
261 | /* Required number taken */ | |
262 | return -EBUSY; | |
263 | } else if (d->devnum > new->devnum) { | |
264 | /* Required number was free */ | |
265 | list_add_tail(&new->list, &d->list); | |
266 | goto added; | |
267 | } | |
268 | last_devnum = d->devnum; | |
269 | } | |
270 | if (new->devnum == -1) | |
271 | new->devnum = last_devnum+1; | |
272 | ||
273 | if ((new->devnum << tr->part_bits) > 256) { | |
274 | return -EBUSY; | |
275 | } | |
276 | ||
277 | init_MUTEX(&new->sem); | |
278 | list_add_tail(&new->list, &tr->devs); | |
279 | added: | |
280 | if (!tr->writesect) | |
281 | new->readonly = 1; | |
282 | ||
283 | gd = alloc_disk(1 << tr->part_bits); | |
284 | if (!gd) { | |
285 | list_del(&new->list); | |
286 | return -ENOMEM; | |
287 | } | |
288 | gd->major = tr->major; | |
289 | gd->first_minor = (new->devnum) << tr->part_bits; | |
290 | gd->fops = &mtd_blktrans_ops; | |
291 | ||
65a8de36 TP |
292 | if (tr->part_bits) |
293 | if (new->devnum < 26) | |
294 | snprintf(gd->disk_name, sizeof(gd->disk_name), | |
295 | "%s%c", tr->name, 'a' + new->devnum); | |
296 | else | |
297 | snprintf(gd->disk_name, sizeof(gd->disk_name), | |
298 | "%s%c%c", tr->name, | |
299 | 'a' - 1 + new->devnum / 26, | |
300 | 'a' + new->devnum % 26); | |
301 | else | |
302 | snprintf(gd->disk_name, sizeof(gd->disk_name), | |
303 | "%s%d", tr->name, new->devnum); | |
1da177e4 LT |
304 | |
305 | /* 2.5 has capacity in units of 512 bytes while still | |
306 | having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */ | |
307 | set_capacity(gd, (new->size * new->blksize) >> 9); | |
308 | ||
309 | gd->private_data = new; | |
310 | new->blkcore_priv = gd; | |
311 | gd->queue = tr->blkcore_priv->rq; | |
312 | ||
313 | if (new->readonly) | |
314 | set_disk_ro(gd, 1); | |
315 | ||
316 | add_disk(gd); | |
317 | ||
318 | return 0; | |
319 | } | |
320 | ||
321 | int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) | |
322 | { | |
323 | if (!down_trylock(&mtd_table_mutex)) { | |
324 | up(&mtd_table_mutex); | |
325 | BUG(); | |
326 | } | |
327 | ||
328 | list_del(&old->list); | |
329 | ||
330 | del_gendisk(old->blkcore_priv); | |
331 | put_disk(old->blkcore_priv); | |
332 | ||
333 | return 0; | |
334 | } | |
335 | ||
336 | static void blktrans_notify_remove(struct mtd_info *mtd) | |
337 | { | |
338 | struct list_head *this, *this2, *next; | |
339 | ||
340 | list_for_each(this, &blktrans_majors) { | |
341 | struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list); | |
342 | ||
343 | list_for_each_safe(this2, next, &tr->devs) { | |
344 | struct mtd_blktrans_dev *dev = list_entry(this2, struct mtd_blktrans_dev, list); | |
345 | ||
346 | if (dev->mtd == mtd) | |
347 | tr->remove_dev(dev); | |
348 | } | |
349 | } | |
350 | } | |
351 | ||
352 | static void blktrans_notify_add(struct mtd_info *mtd) | |
353 | { | |
354 | struct list_head *this; | |
355 | ||
356 | if (mtd->type == MTD_ABSENT) | |
357 | return; | |
358 | ||
359 | list_for_each(this, &blktrans_majors) { | |
360 | struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list); | |
361 | ||
362 | tr->add_mtd(tr, mtd); | |
363 | } | |
364 | ||
365 | } | |
366 | ||
367 | static struct mtd_notifier blktrans_notifier = { | |
368 | .add = blktrans_notify_add, | |
369 | .remove = blktrans_notify_remove, | |
370 | }; | |
371 | ||
372 | int register_mtd_blktrans(struct mtd_blktrans_ops *tr) | |
373 | { | |
374 | int ret, i; | |
375 | ||
376 | /* Register the notifier if/when the first device type is | |
377 | registered, to prevent the link/init ordering from fucking | |
378 | us over. */ | |
379 | if (!blktrans_notifier.list.next) | |
380 | register_mtd_user(&blktrans_notifier); | |
381 | ||
382 | tr->blkcore_priv = kmalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL); | |
383 | if (!tr->blkcore_priv) | |
384 | return -ENOMEM; | |
385 | ||
386 | memset(tr->blkcore_priv, 0, sizeof(*tr->blkcore_priv)); | |
387 | ||
388 | down(&mtd_table_mutex); | |
389 | ||
390 | ret = register_blkdev(tr->major, tr->name); | |
391 | if (ret) { | |
392 | printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", | |
393 | tr->name, tr->major, ret); | |
394 | kfree(tr->blkcore_priv); | |
395 | up(&mtd_table_mutex); | |
396 | return ret; | |
397 | } | |
398 | spin_lock_init(&tr->blkcore_priv->queue_lock); | |
399 | init_completion(&tr->blkcore_priv->thread_dead); | |
400 | init_waitqueue_head(&tr->blkcore_priv->thread_wq); | |
401 | ||
402 | tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock); | |
403 | if (!tr->blkcore_priv->rq) { | |
404 | unregister_blkdev(tr->major, tr->name); | |
405 | kfree(tr->blkcore_priv); | |
406 | up(&mtd_table_mutex); | |
407 | return -ENOMEM; | |
408 | } | |
409 | ||
410 | tr->blkcore_priv->rq->queuedata = tr; | |
411 | ||
412 | ret = kernel_thread(mtd_blktrans_thread, tr, CLONE_KERNEL); | |
413 | if (ret < 0) { | |
414 | blk_cleanup_queue(tr->blkcore_priv->rq); | |
415 | unregister_blkdev(tr->major, tr->name); | |
416 | kfree(tr->blkcore_priv); | |
417 | up(&mtd_table_mutex); | |
418 | return ret; | |
419 | } | |
420 | ||
1da177e4 LT |
421 | INIT_LIST_HEAD(&tr->devs); |
422 | list_add(&tr->list, &blktrans_majors); | |
423 | ||
424 | for (i=0; i<MAX_MTD_DEVICES; i++) { | |
425 | if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT) | |
426 | tr->add_mtd(tr, mtd_table[i]); | |
427 | } | |
428 | ||
429 | up(&mtd_table_mutex); | |
430 | ||
431 | return 0; | |
432 | } | |
433 | ||
434 | int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) | |
435 | { | |
436 | struct list_head *this, *next; | |
437 | ||
438 | down(&mtd_table_mutex); | |
439 | ||
440 | /* Clean up the kernel thread */ | |
441 | tr->blkcore_priv->exiting = 1; | |
442 | wake_up(&tr->blkcore_priv->thread_wq); | |
443 | wait_for_completion(&tr->blkcore_priv->thread_dead); | |
444 | ||
445 | /* Remove it from the list of active majors */ | |
446 | list_del(&tr->list); | |
447 | ||
448 | list_for_each_safe(this, next, &tr->devs) { | |
449 | struct mtd_blktrans_dev *dev = list_entry(this, struct mtd_blktrans_dev, list); | |
450 | tr->remove_dev(dev); | |
451 | } | |
452 | ||
1da177e4 LT |
453 | blk_cleanup_queue(tr->blkcore_priv->rq); |
454 | unregister_blkdev(tr->major, tr->name); | |
455 | ||
456 | up(&mtd_table_mutex); | |
457 | ||
458 | kfree(tr->blkcore_priv); | |
459 | ||
460 | if (!list_empty(&tr->devs)) | |
461 | BUG(); | |
462 | return 0; | |
463 | } | |
464 | ||
465 | static void __exit mtd_blktrans_exit(void) | |
466 | { | |
467 | /* No race here -- if someone's currently in register_mtd_blktrans | |
468 | we're screwed anyway. */ | |
469 | if (blktrans_notifier.list.next) | |
470 | unregister_mtd_user(&blktrans_notifier); | |
471 | } | |
472 | ||
473 | module_exit(mtd_blktrans_exit); | |
474 | ||
475 | EXPORT_SYMBOL_GPL(register_mtd_blktrans); | |
476 | EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); | |
477 | EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); | |
478 | EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); | |
479 | ||
480 | MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); | |
481 | MODULE_LICENSE("GPL"); | |
482 | MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); |