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;
253 mutex_unlock(&dev->lock);
254 blktrans_dev_put(dev);
258 static const struct block_device_operations mtd_blktrans_ops = {
259 .owner = THIS_MODULE,
260 .open = blktrans_open,
261 .release = blktrans_release,
262 .locked_ioctl = blktrans_ioctl,
263 .getgeo = blktrans_getgeo,
266 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
268 struct mtd_blktrans_ops *tr = new->tr;
269 struct mtd_blktrans_dev *d;
270 int last_devnum = -1;
274 if (mutex_trylock(&mtd_table_mutex)) {
275 mutex_unlock(&mtd_table_mutex);
279 mutex_lock(&blktrans_ref_mutex);
280 list_for_each_entry(d, &tr->devs, list) {
281 if (new->devnum == -1) {
282 /* Use first free number */
283 if (d->devnum != last_devnum+1) {
284 /* Found a free devnum. Plug it in here */
285 new->devnum = last_devnum+1;
286 list_add_tail(&new->list, &d->list);
289 } else if (d->devnum == new->devnum) {
290 /* Required number taken */
291 mutex_unlock(&blktrans_ref_mutex);
293 } else if (d->devnum > new->devnum) {
294 /* Required number was free */
295 list_add_tail(&new->list, &d->list);
298 last_devnum = d->devnum;
302 if (new->devnum == -1)
303 new->devnum = last_devnum+1;
305 /* Check that the device and any partitions will get valid
306 * minor numbers and that the disk naming code below can cope
307 * with this number. */
308 if (new->devnum > (MINORMASK >> tr->part_bits) ||
309 (tr->part_bits && new->devnum >= 27 * 26)) {
310 mutex_unlock(&blktrans_ref_mutex);
314 list_add_tail(&new->list, &tr->devs);
316 mutex_unlock(&blktrans_ref_mutex);
318 mutex_init(&new->lock);
319 kref_init(&new->ref);
325 gd = alloc_disk(1 << tr->part_bits);
331 gd->private_data = new;
332 gd->major = tr->major;
333 gd->first_minor = (new->devnum) << tr->part_bits;
334 gd->fops = &mtd_blktrans_ops;
337 if (new->devnum < 26)
338 snprintf(gd->disk_name, sizeof(gd->disk_name),
339 "%s%c", tr->name, 'a' + new->devnum);
341 snprintf(gd->disk_name, sizeof(gd->disk_name),
343 'a' - 1 + new->devnum / 26,
344 'a' + new->devnum % 26);
346 snprintf(gd->disk_name, sizeof(gd->disk_name),
347 "%s%d", tr->name, new->devnum);
349 set_capacity(gd, (new->size * tr->blksize) >> 9);
351 /* Create the request queue */
352 spin_lock_init(&new->queue_lock);
353 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
358 new->rq->queuedata = new;
359 blk_queue_logical_block_size(new->rq, tr->blksize);
362 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
367 __get_mtd_device(new->mtd);
368 __module_get(tr->owner);
370 /* Create processing thread */
371 /* TODO: workqueue ? */
372 new->thread = kthread_run(mtd_blktrans_thread, new,
373 "%s%d", tr->name, new->mtd->index);
374 if (IS_ERR(new->thread)) {
375 ret = PTR_ERR(new->thread);
378 gd->driverfs_dev = &new->mtd->dev;
385 if (new->disk_attributes) {
386 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
387 new->disk_attributes);
392 module_put(tr->owner);
393 __put_mtd_device(new->mtd);
394 blk_cleanup_queue(new->rq);
398 list_del(&new->list);
404 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
408 if (mutex_trylock(&mtd_table_mutex)) {
409 mutex_unlock(&mtd_table_mutex);
413 if (old->disk_attributes)
414 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
415 old->disk_attributes);
417 /* Stop new requests to arrive */
418 del_gendisk(old->disk);
421 /* Stop the thread */
422 kthread_stop(old->thread);
424 /* Kill current requests */
425 spin_lock_irqsave(&old->queue_lock, flags);
426 old->rq->queuedata = NULL;
427 blk_start_queue(old->rq);
428 spin_unlock_irqrestore(&old->queue_lock, flags);
430 /* Ask trans driver for release to the mtd device */
431 mutex_lock(&old->lock);
432 if (old->open && old->tr->release) {
433 old->tr->release(old);
437 __put_mtd_device(old->mtd);
438 module_put(old->tr->owner);
440 /* At that point, we don't touch the mtd anymore */
443 mutex_unlock(&old->lock);
444 blktrans_dev_put(old);
448 static void blktrans_notify_remove(struct mtd_info *mtd)
450 struct mtd_blktrans_ops *tr;
451 struct mtd_blktrans_dev *dev, *next;
453 list_for_each_entry(tr, &blktrans_majors, list)
454 list_for_each_entry_safe(dev, next, &tr->devs, list)
459 static void blktrans_notify_add(struct mtd_info *mtd)
461 struct mtd_blktrans_ops *tr;
463 if (mtd->type == MTD_ABSENT)
466 list_for_each_entry(tr, &blktrans_majors, list)
467 tr->add_mtd(tr, mtd);
470 static struct mtd_notifier blktrans_notifier = {
471 .add = blktrans_notify_add,
472 .remove = blktrans_notify_remove,
475 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
477 struct mtd_info *mtd;
480 /* Register the notifier if/when the first device type is
481 registered, to prevent the link/init ordering from fucking
483 if (!blktrans_notifier.list.next)
484 register_mtd_user(&blktrans_notifier);
487 mutex_lock(&mtd_table_mutex);
489 ret = register_blkdev(tr->major, tr->name);
491 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
492 tr->name, tr->major, ret);
493 mutex_unlock(&mtd_table_mutex);
497 tr->blkshift = ffs(tr->blksize) - 1;
499 INIT_LIST_HEAD(&tr->devs);
500 list_add(&tr->list, &blktrans_majors);
502 mtd_for_each_device(mtd)
503 if (mtd->type != MTD_ABSENT)
504 tr->add_mtd(tr, mtd);
506 mutex_unlock(&mtd_table_mutex);
510 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
512 struct mtd_blktrans_dev *dev, *next;
514 mutex_lock(&mtd_table_mutex);
516 /* Remove it from the list of active majors */
519 list_for_each_entry_safe(dev, next, &tr->devs, list)
522 unregister_blkdev(tr->major, tr->name);
523 mutex_unlock(&mtd_table_mutex);
525 BUG_ON(!list_empty(&tr->devs));
529 static void __exit mtd_blktrans_exit(void)
531 /* No race here -- if someone's currently in register_mtd_blktrans
532 we're screwed anyway. */
533 if (blktrans_notifier.list.next)
534 unregister_mtd_user(&blktrans_notifier);
537 module_exit(mtd_blktrans_exit);
539 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
540 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
541 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
542 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
544 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
545 MODULE_LICENSE("GPL");
546 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");