drm/vmwgfx: Don't send bad flags to the host
[linux-2.6.git] / drivers / mtd / mtd_blkdevs.c
1 /*
2  * (C) 2003 David Woodhouse <dwmw2@infradead.org>
3  *
4  * Interface to Linux 2.5 block layer for MTD 'translation layers'.
5  *
6  */
7
8 #include <linux/kernel.h>
9 #include <linux/slab.h>
10 #include <linux/module.h>
11 #include <linux/list.h>
12 #include <linux/fs.h>
13 #include <linux/mtd/blktrans.h>
14 #include <linux/mtd/mtd.h>
15 #include <linux/blkdev.h>
16 #include <linux/blkpg.h>
17 #include <linux/freezer.h>
18 #include <linux/spinlock.h>
19 #include <linux/hdreg.h>
20 #include <linux/init.h>
21 #include <linux/mutex.h>
22 #include <linux/kthread.h>
23 #include <asm/uaccess.h>
24
25 #include "mtdcore.h"
26
27 static LIST_HEAD(blktrans_majors);
28
29 struct mtd_blkcore_priv {
30         struct task_struct *thread;
31         struct request_queue *rq;
32         spinlock_t queue_lock;
33 };
34
35 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
36                                struct mtd_blktrans_dev *dev,
37                                struct request *req)
38 {
39         unsigned long block, nsect;
40         char *buf;
41
42         block = blk_rq_pos(req) << 9 >> tr->blkshift;
43         nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
44
45         buf = req->buffer;
46
47         if (!blk_fs_request(req))
48                 return -EIO;
49
50         if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
51             get_capacity(req->rq_disk))
52                 return -EIO;
53
54         if (blk_discard_rq(req))
55                 return tr->discard(dev, block, nsect);
56
57         switch(rq_data_dir(req)) {
58         case READ:
59                 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
60                         if (tr->readsect(dev, block, buf))
61                                 return -EIO;
62                 return 0;
63
64         case WRITE:
65                 if (!tr->writesect)
66                         return -EIO;
67
68                 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
69                         if (tr->writesect(dev, block, buf))
70                                 return -EIO;
71                 return 0;
72
73         default:
74                 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
75                 return -EIO;
76         }
77 }
78
79 static int mtd_blktrans_thread(void *arg)
80 {
81         struct mtd_blktrans_ops *tr = arg;
82         struct request_queue *rq = tr->blkcore_priv->rq;
83         struct request *req = NULL;
84
85         /* we might get involved when memory gets low, so use PF_MEMALLOC */
86         current->flags |= PF_MEMALLOC;
87
88         spin_lock_irq(rq->queue_lock);
89
90         while (!kthread_should_stop()) {
91                 struct mtd_blktrans_dev *dev;
92                 int res;
93
94                 if (!req && !(req = blk_fetch_request(rq))) {
95                         set_current_state(TASK_INTERRUPTIBLE);
96                         spin_unlock_irq(rq->queue_lock);
97                         schedule();
98                         spin_lock_irq(rq->queue_lock);
99                         continue;
100                 }
101
102                 dev = req->rq_disk->private_data;
103                 tr = dev->tr;
104
105                 spin_unlock_irq(rq->queue_lock);
106
107                 mutex_lock(&dev->lock);
108                 res = do_blktrans_request(tr, dev, req);
109                 mutex_unlock(&dev->lock);
110
111                 spin_lock_irq(rq->queue_lock);
112
113                 if (!__blk_end_request_cur(req, res))
114                         req = NULL;
115         }
116
117         if (req)
118                 __blk_end_request_all(req, -EIO);
119
120         spin_unlock_irq(rq->queue_lock);
121
122         return 0;
123 }
124
125 static void mtd_blktrans_request(struct request_queue *rq)
126 {
127         struct mtd_blktrans_ops *tr = rq->queuedata;
128         wake_up_process(tr->blkcore_priv->thread);
129 }
130
131
132 static int blktrans_open(struct block_device *bdev, fmode_t mode)
133 {
134         struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
135         struct mtd_blktrans_ops *tr = dev->tr;
136         int ret = -ENODEV;
137
138         if (!get_mtd_device(NULL, dev->mtd->index))
139                 goto out;
140
141         if (!try_module_get(tr->owner))
142                 goto out_tr;
143
144         /* FIXME: Locking. A hot pluggable device can go away
145            (del_mtd_device can be called for it) without its module
146            being unloaded. */
147         dev->mtd->usecount++;
148
149         ret = 0;
150         if (tr->open && (ret = tr->open(dev))) {
151                 dev->mtd->usecount--;
152                 put_mtd_device(dev->mtd);
153         out_tr:
154                 module_put(tr->owner);
155         }
156  out:
157         return ret;
158 }
159
160 static int blktrans_release(struct gendisk *disk, fmode_t mode)
161 {
162         struct mtd_blktrans_dev *dev = disk->private_data;
163         struct mtd_blktrans_ops *tr = dev->tr;
164         int ret = 0;
165
166         if (tr->release)
167                 ret = tr->release(dev);
168
169         if (!ret) {
170                 dev->mtd->usecount--;
171                 put_mtd_device(dev->mtd);
172                 module_put(tr->owner);
173         }
174
175         return ret;
176 }
177
178 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
179 {
180         struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
181
182         if (dev->tr->getgeo)
183                 return dev->tr->getgeo(dev, geo);
184         return -ENOTTY;
185 }
186
187 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
188                               unsigned int cmd, unsigned long arg)
189 {
190         struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
191         struct mtd_blktrans_ops *tr = dev->tr;
192
193         switch (cmd) {
194         case BLKFLSBUF:
195                 if (tr->flush)
196                         return tr->flush(dev);
197                 /* The core code did the work, we had nothing to do. */
198                 return 0;
199         default:
200                 return -ENOTTY;
201         }
202 }
203
204 static const struct block_device_operations mtd_blktrans_ops = {
205         .owner          = THIS_MODULE,
206         .open           = blktrans_open,
207         .release        = blktrans_release,
208         .locked_ioctl   = blktrans_ioctl,
209         .getgeo         = blktrans_getgeo,
210 };
211
212 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
213 {
214         struct mtd_blktrans_ops *tr = new->tr;
215         struct mtd_blktrans_dev *d;
216         int last_devnum = -1;
217         struct gendisk *gd;
218
219         if (mutex_trylock(&mtd_table_mutex)) {
220                 mutex_unlock(&mtd_table_mutex);
221                 BUG();
222         }
223
224         list_for_each_entry(d, &tr->devs, list) {
225                 if (new->devnum == -1) {
226                         /* Use first free number */
227                         if (d->devnum != last_devnum+1) {
228                                 /* Found a free devnum. Plug it in here */
229                                 new->devnum = last_devnum+1;
230                                 list_add_tail(&new->list, &d->list);
231                                 goto added;
232                         }
233                 } else if (d->devnum == new->devnum) {
234                         /* Required number taken */
235                         return -EBUSY;
236                 } else if (d->devnum > new->devnum) {
237                         /* Required number was free */
238                         list_add_tail(&new->list, &d->list);
239                         goto added;
240                 }
241                 last_devnum = d->devnum;
242         }
243         if (new->devnum == -1)
244                 new->devnum = last_devnum+1;
245
246         if ((new->devnum << tr->part_bits) > 256) {
247                 return -EBUSY;
248         }
249
250         list_add_tail(&new->list, &tr->devs);
251  added:
252         mutex_init(&new->lock);
253         if (!tr->writesect)
254                 new->readonly = 1;
255
256         gd = alloc_disk(1 << tr->part_bits);
257         if (!gd) {
258                 list_del(&new->list);
259                 return -ENOMEM;
260         }
261         gd->major = tr->major;
262         gd->first_minor = (new->devnum) << tr->part_bits;
263         gd->fops = &mtd_blktrans_ops;
264
265         if (tr->part_bits)
266                 if (new->devnum < 26)
267                         snprintf(gd->disk_name, sizeof(gd->disk_name),
268                                  "%s%c", tr->name, 'a' + new->devnum);
269                 else
270                         snprintf(gd->disk_name, sizeof(gd->disk_name),
271                                  "%s%c%c", tr->name,
272                                  'a' - 1 + new->devnum / 26,
273                                  'a' + new->devnum % 26);
274         else
275                 snprintf(gd->disk_name, sizeof(gd->disk_name),
276                          "%s%d", tr->name, new->devnum);
277
278         /* 2.5 has capacity in units of 512 bytes while still
279            having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
280         set_capacity(gd, (new->size * tr->blksize) >> 9);
281
282         gd->private_data = new;
283         new->blkcore_priv = gd;
284         gd->queue = tr->blkcore_priv->rq;
285         gd->driverfs_dev = &new->mtd->dev;
286
287         if (new->readonly)
288                 set_disk_ro(gd, 1);
289
290         add_disk(gd);
291
292         return 0;
293 }
294
295 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
296 {
297         if (mutex_trylock(&mtd_table_mutex)) {
298                 mutex_unlock(&mtd_table_mutex);
299                 BUG();
300         }
301
302         list_del(&old->list);
303
304         del_gendisk(old->blkcore_priv);
305         put_disk(old->blkcore_priv);
306
307         return 0;
308 }
309
310 static void blktrans_notify_remove(struct mtd_info *mtd)
311 {
312         struct mtd_blktrans_ops *tr;
313         struct mtd_blktrans_dev *dev, *next;
314
315         list_for_each_entry(tr, &blktrans_majors, list)
316                 list_for_each_entry_safe(dev, next, &tr->devs, list)
317                         if (dev->mtd == mtd)
318                                 tr->remove_dev(dev);
319 }
320
321 static void blktrans_notify_add(struct mtd_info *mtd)
322 {
323         struct mtd_blktrans_ops *tr;
324
325         if (mtd->type == MTD_ABSENT)
326                 return;
327
328         list_for_each_entry(tr, &blktrans_majors, list)
329                 tr->add_mtd(tr, mtd);
330 }
331
332 static struct mtd_notifier blktrans_notifier = {
333         .add = blktrans_notify_add,
334         .remove = blktrans_notify_remove,
335 };
336
337 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
338 {
339         int ret, i;
340
341         /* Register the notifier if/when the first device type is
342            registered, to prevent the link/init ordering from fucking
343            us over. */
344         if (!blktrans_notifier.list.next)
345                 register_mtd_user(&blktrans_notifier);
346
347         tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
348         if (!tr->blkcore_priv)
349                 return -ENOMEM;
350
351         mutex_lock(&mtd_table_mutex);
352
353         ret = register_blkdev(tr->major, tr->name);
354         if (ret) {
355                 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
356                        tr->name, tr->major, ret);
357                 kfree(tr->blkcore_priv);
358                 mutex_unlock(&mtd_table_mutex);
359                 return ret;
360         }
361         spin_lock_init(&tr->blkcore_priv->queue_lock);
362
363         tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
364         if (!tr->blkcore_priv->rq) {
365                 unregister_blkdev(tr->major, tr->name);
366                 kfree(tr->blkcore_priv);
367                 mutex_unlock(&mtd_table_mutex);
368                 return -ENOMEM;
369         }
370
371         tr->blkcore_priv->rq->queuedata = tr;
372         blk_queue_logical_block_size(tr->blkcore_priv->rq, tr->blksize);
373         if (tr->discard)
374                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
375                                         tr->blkcore_priv->rq);
376
377         tr->blkshift = ffs(tr->blksize) - 1;
378
379         tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
380                         "%sd", tr->name);
381         if (IS_ERR(tr->blkcore_priv->thread)) {
382                 int ret = PTR_ERR(tr->blkcore_priv->thread);
383                 blk_cleanup_queue(tr->blkcore_priv->rq);
384                 unregister_blkdev(tr->major, tr->name);
385                 kfree(tr->blkcore_priv);
386                 mutex_unlock(&mtd_table_mutex);
387                 return ret;
388         }
389
390         INIT_LIST_HEAD(&tr->devs);
391         list_add(&tr->list, &blktrans_majors);
392
393         for (i=0; i<MAX_MTD_DEVICES; i++) {
394                 if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
395                         tr->add_mtd(tr, mtd_table[i]);
396         }
397
398         mutex_unlock(&mtd_table_mutex);
399
400         return 0;
401 }
402
403 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
404 {
405         struct mtd_blktrans_dev *dev, *next;
406
407         mutex_lock(&mtd_table_mutex);
408
409         /* Clean up the kernel thread */
410         kthread_stop(tr->blkcore_priv->thread);
411
412         /* Remove it from the list of active majors */
413         list_del(&tr->list);
414
415         list_for_each_entry_safe(dev, next, &tr->devs, list)
416                 tr->remove_dev(dev);
417
418         blk_cleanup_queue(tr->blkcore_priv->rq);
419         unregister_blkdev(tr->major, tr->name);
420
421         mutex_unlock(&mtd_table_mutex);
422
423         kfree(tr->blkcore_priv);
424
425         BUG_ON(!list_empty(&tr->devs));
426         return 0;
427 }
428
429 static void __exit mtd_blktrans_exit(void)
430 {
431         /* No race here -- if someone's currently in register_mtd_blktrans
432            we're screwed anyway. */
433         if (blktrans_notifier.list.next)
434                 unregister_mtd_user(&blktrans_notifier);
435 }
436
437 module_exit(mtd_blktrans_exit);
438
439 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
440 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
441 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
442 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
443
444 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
445 MODULE_LICENSE("GPL");
446 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");