2 * (C) 2003 David Woodhouse <dwmw2@infradead.org>
4 * Interface to Linux 2.5 block layer for MTD 'translation layers'.
8 #include <linux/kernel.h>
9 #include <linux/slab.h>
10 #include <linux/module.h>
11 #include <linux/list.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/spinlock.h>
18 #include <linux/hdreg.h>
19 #include <linux/init.h>
20 #include <linux/mutex.h>
21 #include <linux/kthread.h>
22 #include <asm/uaccess.h>
26 static LIST_HEAD(blktrans_majors);
27 static DEFINE_MUTEX(blktrans_ref_mutex);
29 void blktrans_dev_release(struct kref *kref)
31 struct mtd_blktrans_dev *dev =
32 container_of(kref, struct mtd_blktrans_dev, ref);
34 dev->disk->private_data = NULL;
35 blk_cleanup_queue(dev->rq);
41 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
43 struct mtd_blktrans_dev *dev;
45 mutex_lock(&blktrans_ref_mutex);
46 dev = disk->private_data;
52 mutex_unlock(&blktrans_ref_mutex);
56 void blktrans_dev_put(struct mtd_blktrans_dev *dev)
58 mutex_lock(&blktrans_ref_mutex);
59 kref_put(&dev->ref, blktrans_dev_release);
60 mutex_unlock(&blktrans_ref_mutex);
64 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
65 struct mtd_blktrans_dev *dev,
68 unsigned long block, nsect;
71 block = blk_rq_pos(req) << 9 >> tr->blkshift;
72 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
76 if (!blk_fs_request(req))
79 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
80 get_capacity(req->rq_disk))
83 if (blk_discard_rq(req))
84 return tr->discard(dev, block, nsect);
86 switch(rq_data_dir(req)) {
88 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
89 if (tr->readsect(dev, block, buf))
91 rq_flush_dcache_pages(req);
97 rq_flush_dcache_pages(req);
98 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
99 if (tr->writesect(dev, block, buf))
103 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
108 static int mtd_blktrans_thread(void *arg)
110 struct mtd_blktrans_dev *dev = arg;
111 struct request_queue *rq = dev->rq;
112 struct request *req = NULL;
114 spin_lock_irq(rq->queue_lock);
116 while (!kthread_should_stop()) {
119 if (!req && !(req = blk_fetch_request(rq))) {
120 set_current_state(TASK_INTERRUPTIBLE);
121 spin_unlock_irq(rq->queue_lock);
123 spin_lock_irq(rq->queue_lock);
127 spin_unlock_irq(rq->queue_lock);
129 mutex_lock(&dev->lock);
130 res = do_blktrans_request(dev->tr, dev, req);
131 mutex_unlock(&dev->lock);
133 spin_lock_irq(rq->queue_lock);
135 if (!__blk_end_request_cur(req, res))
140 __blk_end_request_all(req, -EIO);
142 spin_unlock_irq(rq->queue_lock);
147 static void mtd_blktrans_request(struct request_queue *rq)
149 struct mtd_blktrans_dev *dev;
150 struct request *req = NULL;
155 while ((req = blk_fetch_request(rq)) != NULL)
156 __blk_end_request_all(req, -ENODEV);
158 wake_up_process(dev->thread);
161 static int blktrans_open(struct block_device *bdev, fmode_t mode)
163 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
169 mutex_lock(&dev->lock);
176 ret = !dev->open++ && dev->tr->open ? dev->tr->open(dev) : 0;
178 /* Take another reference on the device so it won't go away till
183 mutex_unlock(&dev->lock);
184 blktrans_dev_put(dev);
188 static int blktrans_release(struct gendisk *disk, fmode_t mode)
190 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
196 mutex_lock(&dev->lock);
198 /* Release one reference, we sure its not the last one here*/
199 kref_put(&dev->ref, blktrans_dev_release);
204 ret = !--dev->open && dev->tr->release ? dev->tr->release(dev) : 0;
206 mutex_unlock(&dev->lock);
207 blktrans_dev_put(dev);
211 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
213 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
219 mutex_lock(&dev->lock);
224 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
226 mutex_unlock(&dev->lock);
227 blktrans_dev_put(dev);
231 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
232 unsigned int cmd, unsigned long arg)
234 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
240 mutex_lock(&dev->lock);
247 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
252 mutex_unlock(&dev->lock);
253 blktrans_dev_put(dev);
257 static const struct block_device_operations mtd_blktrans_ops = {
258 .owner = THIS_MODULE,
259 .open = blktrans_open,
260 .release = blktrans_release,
261 .locked_ioctl = blktrans_ioctl,
262 .getgeo = blktrans_getgeo,
265 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
267 struct mtd_blktrans_ops *tr = new->tr;
268 struct mtd_blktrans_dev *d;
269 int last_devnum = -1;
273 if (mutex_trylock(&mtd_table_mutex)) {
274 mutex_unlock(&mtd_table_mutex);
278 mutex_lock(&blktrans_ref_mutex);
279 list_for_each_entry(d, &tr->devs, list) {
280 if (new->devnum == -1) {
281 /* Use first free number */
282 if (d->devnum != last_devnum+1) {
283 /* Found a free devnum. Plug it in here */
284 new->devnum = last_devnum+1;
285 list_add_tail(&new->list, &d->list);
288 } else if (d->devnum == new->devnum) {
289 /* Required number taken */
290 mutex_unlock(&blktrans_ref_mutex);
292 } else if (d->devnum > new->devnum) {
293 /* Required number was free */
294 list_add_tail(&new->list, &d->list);
297 last_devnum = d->devnum;
301 if (new->devnum == -1)
302 new->devnum = last_devnum+1;
304 /* Check that the device and any partitions will get valid
305 * minor numbers and that the disk naming code below can cope
306 * with this number. */
307 if (new->devnum > (MINORMASK >> tr->part_bits) ||
308 (tr->part_bits && new->devnum >= 27 * 26)) {
309 mutex_unlock(&blktrans_ref_mutex);
313 list_add_tail(&new->list, &tr->devs);
315 mutex_unlock(&blktrans_ref_mutex);
317 mutex_init(&new->lock);
318 kref_init(&new->ref);
324 gd = alloc_disk(1 << tr->part_bits);
330 gd->private_data = new;
331 gd->major = tr->major;
332 gd->first_minor = (new->devnum) << tr->part_bits;
333 gd->fops = &mtd_blktrans_ops;
336 if (new->devnum < 26)
337 snprintf(gd->disk_name, sizeof(gd->disk_name),
338 "%s%c", tr->name, 'a' + new->devnum);
340 snprintf(gd->disk_name, sizeof(gd->disk_name),
342 'a' - 1 + new->devnum / 26,
343 'a' + new->devnum % 26);
345 snprintf(gd->disk_name, sizeof(gd->disk_name),
346 "%s%d", tr->name, new->devnum);
348 set_capacity(gd, (new->size * tr->blksize) >> 9);
350 /* Create the request queue */
351 spin_lock_init(&new->queue_lock);
352 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
357 new->rq->queuedata = new;
358 blk_queue_logical_block_size(new->rq, tr->blksize);
361 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
366 __get_mtd_device(new->mtd);
367 __module_get(tr->owner);
369 /* Create processing thread */
370 /* TODO: workqueue ? */
371 new->thread = kthread_run(mtd_blktrans_thread, new,
372 "%s%d", tr->name, new->mtd->index);
373 if (IS_ERR(new->thread)) {
374 ret = PTR_ERR(new->thread);
377 gd->driverfs_dev = &new->mtd->dev;
384 if (new->disk_attributes) {
385 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
386 new->disk_attributes);
391 module_put(tr->owner);
392 __put_mtd_device(new->mtd);
393 blk_cleanup_queue(new->rq);
397 list_del(&new->list);
403 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
407 if (mutex_trylock(&mtd_table_mutex)) {
408 mutex_unlock(&mtd_table_mutex);
412 /* Stop new requests to arrive */
413 del_gendisk(old->disk);
415 if (old->disk_attributes)
416 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
417 old->disk_attributes);
419 /* Stop the thread */
420 kthread_stop(old->thread);
422 /* Kill current requests */
423 spin_lock_irqsave(&old->queue_lock, flags);
424 old->rq->queuedata = NULL;
425 blk_start_queue(old->rq);
426 spin_unlock_irqrestore(&old->queue_lock, flags);
428 /* Ask trans driver for release to the mtd device */
429 mutex_lock(&old->lock);
430 if (old->open && old->tr->release) {
431 old->tr->release(old);
435 __put_mtd_device(old->mtd);
436 module_put(old->tr->owner);
438 /* At that point, we don't touch the mtd anymore */
441 mutex_unlock(&old->lock);
442 blktrans_dev_put(old);
446 static void blktrans_notify_remove(struct mtd_info *mtd)
448 struct mtd_blktrans_ops *tr;
449 struct mtd_blktrans_dev *dev, *next;
451 list_for_each_entry(tr, &blktrans_majors, list)
452 list_for_each_entry_safe(dev, next, &tr->devs, list)
457 static void blktrans_notify_add(struct mtd_info *mtd)
459 struct mtd_blktrans_ops *tr;
461 if (mtd->type == MTD_ABSENT)
464 list_for_each_entry(tr, &blktrans_majors, list)
465 tr->add_mtd(tr, mtd);
468 static struct mtd_notifier blktrans_notifier = {
469 .add = blktrans_notify_add,
470 .remove = blktrans_notify_remove,
473 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
475 struct mtd_info *mtd;
478 /* Register the notifier if/when the first device type is
479 registered, to prevent the link/init ordering from fucking
481 if (!blktrans_notifier.list.next)
482 register_mtd_user(&blktrans_notifier);
485 mutex_lock(&mtd_table_mutex);
487 ret = register_blkdev(tr->major, tr->name);
489 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
490 tr->name, tr->major, ret);
491 mutex_unlock(&mtd_table_mutex);
495 tr->blkshift = ffs(tr->blksize) - 1;
497 INIT_LIST_HEAD(&tr->devs);
498 list_add(&tr->list, &blktrans_majors);
500 mtd_for_each_device(mtd)
501 if (mtd->type != MTD_ABSENT)
502 tr->add_mtd(tr, mtd);
504 mutex_unlock(&mtd_table_mutex);
508 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
510 struct mtd_blktrans_dev *dev, *next;
512 mutex_lock(&mtd_table_mutex);
514 /* Remove it from the list of active majors */
517 list_for_each_entry_safe(dev, next, &tr->devs, list)
520 unregister_blkdev(tr->major, tr->name);
521 mutex_unlock(&mtd_table_mutex);
523 BUG_ON(!list_empty(&tr->devs));
527 static void __exit mtd_blktrans_exit(void)
529 /* No race here -- if someone's currently in register_mtd_blktrans
530 we're screwed anyway. */
531 if (blktrans_notifier.list.next)
532 unregister_mtd_user(&blktrans_notifier);
535 module_exit(mtd_blktrans_exit);
537 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
538 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
539 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
540 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
542 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
543 MODULE_LICENSE("GPL");
544 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");