[linux.git] / drivers / mtd / mtd_blkdevs.c

/*
 * (C) 2003 David Woodhouse <[email protected]>
 *
 * Interface to Linux 2.5 block layer for MTD 'translation layers'.
 *
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/fs.h>
#include <linux/mtd/blktrans.h>
#include <linux/mtd/mtd.h>
#include <linux/blkdev.h>
#include <linux/blkpg.h>
#include <linux/freezer.h>
#include <linux/spinlock.h>
#include <linux/hdreg.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/kthread.h>
#include <asm/uaccess.h>

#include "mtdcore.h"

static LIST_HEAD(blktrans_majors);

struct mtd_blkcore_priv {
	struct task_struct *thread;
	struct request_queue *rq;
	spinlock_t queue_lock;
};

static int do_blktrans_request(struct mtd_blktrans_ops *tr,
			       struct mtd_blktrans_dev *dev,
			       struct request *req)
{
	unsigned long block, nsect;
	char *buf;

	block = blk_rq_pos(req) << 9 >> tr->blkshift;
	nsect = blk_rq_cur_bytes(req) >> tr->blkshift;

	buf = req->buffer;

	if (!blk_fs_request(req))
		return -EIO;

	if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
	    get_capacity(req->rq_disk))
		return -EIO;

	if (blk_discard_rq(req))
		return tr->discard(dev, block, nsect);

	switch(rq_data_dir(req)) {
	case READ:
		for (; nsect > 0; nsect--, block++, buf += tr->blksize)
			if (tr->readsect(dev, block, buf))
				return -EIO;
		rq_flush_dcache_pages(req);
		return 0;

	case WRITE:
		if (!tr->writesect)
			return -EIO;

		rq_flush_dcache_pages(req);
		for (; nsect > 0; nsect--, block++, buf += tr->blksize)
			if (tr->writesect(dev, block, buf))
				return -EIO;
		return 0;

	default:
		printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
		return -EIO;
	}
}

static int mtd_blktrans_thread(void *arg)
{
	struct mtd_blktrans_ops *tr = arg;
	struct request_queue *rq = tr->blkcore_priv->rq;
	struct request *req = NULL;

	/* we might get involved when memory gets low, so use PF_MEMALLOC */
	current->flags |= PF_MEMALLOC;

	spin_lock_irq(rq->queue_lock);

	while (!kthread_should_stop()) {
		struct mtd_blktrans_dev *dev;
		int res;

		if (!req && !(req = blk_fetch_request(rq))) {
			set_current_state(TASK_INTERRUPTIBLE);
			spin_unlock_irq(rq->queue_lock);
			schedule();
			spin_lock_irq(rq->queue_lock);
			continue;
		}

		dev = req->rq_disk->private_data;
		tr = dev->tr;

		spin_unlock_irq(rq->queue_lock);

		mutex_lock(&dev->lock);
		res = do_blktrans_request(tr, dev, req);
		mutex_unlock(&dev->lock);

		spin_lock_irq(rq->queue_lock);

		if (!__blk_end_request_cur(req, res))
			req = NULL;
	}

	if (req)
		__blk_end_request_all(req, -EIO);

	spin_unlock_irq(rq->queue_lock);

	return 0;
}

static void mtd_blktrans_request(struct request_queue *rq)
{
	struct mtd_blktrans_ops *tr = rq->queuedata;
	wake_up_process(tr->blkcore_priv->thread);
}


static int blktrans_open(struct block_device *bdev, fmode_t mode)
{
	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
	struct mtd_blktrans_ops *tr = dev->tr;
	int ret = -ENODEV;

	if (!get_mtd_device(NULL, dev->mtd->index))
		goto out;

	if (!try_module_get(tr->owner))
		goto out_tr;

	/* FIXME: Locking. A hot pluggable device can go away
	   (del_mtd_device can be called for it) without its module
	   being unloaded. */
	dev->mtd->usecount++;

	ret = 0;
	if (tr->open && (ret = tr->open(dev))) {
		dev->mtd->usecount--;
		put_mtd_device(dev->mtd);
	out_tr:
		module_put(tr->owner);
	}
 out:
	return ret;
}

static int blktrans_release(struct gendisk *disk, fmode_t mode)
{
	struct mtd_blktrans_dev *dev = disk->private_data;
	struct mtd_blktrans_ops *tr = dev->tr;
	int ret = 0;

	if (tr->release)
		ret = tr->release(dev);

	if (!ret) {
		dev->mtd->usecount--;
		put_mtd_device(dev->mtd);
		module_put(tr->owner);
	}

	return ret;
}

static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;

	if (dev->tr->getgeo)
		return dev->tr->getgeo(dev, geo);
	return -ENOTTY;
}

static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
			      unsigned int cmd, unsigned long arg)
{
	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
	struct mtd_blktrans_ops *tr = dev->tr;

	switch (cmd) {
	case BLKFLSBUF:
		if (tr->flush)
			return tr->flush(dev);
		/* The core code did the work, we had nothing to do. */
		return 0;
	default:
		return -ENOTTY;
	}
}

static const struct block_device_operations mtd_blktrans_ops = {
	.owner		= THIS_MODULE,
	.open		= blktrans_open,
	.release	= blktrans_release,
	.locked_ioctl	= blktrans_ioctl,
	.getgeo		= blktrans_getgeo,
};

int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
{
	struct mtd_blktrans_ops *tr = new->tr;
	struct mtd_blktrans_dev *d;
	int last_devnum = -1;
	struct gendisk *gd;

	if (mutex_trylock(&mtd_table_mutex)) {
		mutex_unlock(&mtd_table_mutex);
		BUG();
	}

	list_for_each_entry(d, &tr->devs, list) {
		if (new->devnum == -1) {
			/* Use first free number */
			if (d->devnum != last_devnum+1) {
				/* Found a free devnum. Plug it in here */
				new->devnum = last_devnum+1;
				list_add_tail(&new->list, &d->list);
				goto added;
			}
		} else if (d->devnum == new->devnum) {
			/* Required number taken */
			return -EBUSY;
		} else if (d->devnum > new->devnum) {
			/* Required number was free */
			list_add_tail(&new->list, &d->list);
			goto added;
		}
		last_devnum = d->devnum;
	}
	if (new->devnum == -1)
		new->devnum = last_devnum+1;

	if ((new->devnum << tr->part_bits) > 256) {
		return -EBUSY;
	}

	list_add_tail(&new->list, &tr->devs);
 added:
	mutex_init(&new->lock);
	if (!tr->writesect)
		new->readonly = 1;

	gd = alloc_disk(1 << tr->part_bits);
	if (!gd) {
		list_del(&new->list);
		return -ENOMEM;
	}
	gd->major = tr->major;
	gd->first_minor = (new->devnum) << tr->part_bits;
	gd->fops = &mtd_blktrans_ops;

	if (tr->part_bits)
		if (new->devnum < 26)
			snprintf(gd->disk_name, sizeof(gd->disk_name),
				 "%s%c", tr->name, 'a' + new->devnum);
		else
			snprintf(gd->disk_name, sizeof(gd->disk_name),
				 "%s%c%c", tr->name,
				 'a' - 1 + new->devnum / 26,
				 'a' + new->devnum % 26);
	else
		snprintf(gd->disk_name, sizeof(gd->disk_name),
			 "%s%d", tr->name, new->devnum);

	/* 2.5 has capacity in units of 512 bytes while still
	   having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
	set_capacity(gd, (new->size * tr->blksize) >> 9);

	gd->private_data = new;
	new->blkcore_priv = gd;
	gd->queue = tr->blkcore_priv->rq;
	gd->driverfs_dev = &new->mtd->dev;

	if (new->readonly)
		set_disk_ro(gd, 1);

	add_disk(gd);

	return 0;
}

int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
{
	if (mutex_trylock(&mtd_table_mutex)) {
		mutex_unlock(&mtd_table_mutex);
		BUG();
	}

	list_del(&old->list);

	del_gendisk(old->blkcore_priv);
	put_disk(old->blkcore_priv);

	return 0;
}

static void blktrans_notify_remove(struct mtd_info *mtd)
{
	struct mtd_blktrans_ops *tr;
	struct mtd_blktrans_dev *dev, *next;

	list_for_each_entry(tr, &blktrans_majors, list)
		list_for_each_entry_safe(dev, next, &tr->devs, list)
			if (dev->mtd == mtd)
				tr->remove_dev(dev);
}

static void blktrans_notify_add(struct mtd_info *mtd)
{
	struct mtd_blktrans_ops *tr;

	if (mtd->type == MTD_ABSENT)
		return;

	list_for_each_entry(tr, &blktrans_majors, list)
		tr->add_mtd(tr, mtd);
}

static struct mtd_notifier blktrans_notifier = {
	.add = blktrans_notify_add,
	.remove = blktrans_notify_remove,
};

int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
{
	int ret, i;

	/* Register the notifier if/when the first device type is
	   registered, to prevent the link/init ordering from fucking
	   us over. */
	if (!blktrans_notifier.list.next)
		register_mtd_user(&blktrans_notifier);

	tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
	if (!tr->blkcore_priv)
		return -ENOMEM;

	mutex_lock(&mtd_table_mutex);

	ret = register_blkdev(tr->major, tr->name);
	if (ret) {
		printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
		       tr->name, tr->major, ret);
		kfree(tr->blkcore_priv);
		mutex_unlock(&mtd_table_mutex);
		return ret;
	}
	spin_lock_init(&tr->blkcore_priv->queue_lock);

	tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
	if (!tr->blkcore_priv->rq) {
		unregister_blkdev(tr->major, tr->name);
		kfree(tr->blkcore_priv);
		mutex_unlock(&mtd_table_mutex);
		return -ENOMEM;
	}

	tr->blkcore_priv->rq->queuedata = tr;
	blk_queue_logical_block_size(tr->blkcore_priv->rq, tr->blksize);
	if (tr->discard)
		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
					tr->blkcore_priv->rq);

	tr->blkshift = ffs(tr->blksize) - 1;

	tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
			"%sd", tr->name);
	if (IS_ERR(tr->blkcore_priv->thread)) {
		int ret = PTR_ERR(tr->blkcore_priv->thread);
		blk_cleanup_queue(tr->blkcore_priv->rq);
		unregister_blkdev(tr->major, tr->name);
		kfree(tr->blkcore_priv);
		mutex_unlock(&mtd_table_mutex);
		return ret;
	}

	INIT_LIST_HEAD(&tr->devs);
	list_add(&tr->list, &blktrans_majors);

	for (i=0; i<MAX_MTD_DEVICES; i++) {
		if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
			tr->add_mtd(tr, mtd_table[i]);
	}

	mutex_unlock(&mtd_table_mutex);

	return 0;
}

int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
{
	struct mtd_blktrans_dev *dev, *next;

	mutex_lock(&mtd_table_mutex);

	/* Clean up the kernel thread */
	kthread_stop(tr->blkcore_priv->thread);

	/* Remove it from the list of active majors */
	list_del(&tr->list);

	list_for_each_entry_safe(dev, next, &tr->devs, list)
		tr->remove_dev(dev);

	blk_cleanup_queue(tr->blkcore_priv->rq);
	unregister_blkdev(tr->major, tr->name);

	mutex_unlock(&mtd_table_mutex);

	kfree(tr->blkcore_priv);

	BUG_ON(!list_empty(&tr->devs));
	return 0;
}

static void __exit mtd_blktrans_exit(void)
{
	/* No race here -- if someone's currently in register_mtd_blktrans
	   we're screwed anyway. */
	if (blktrans_notifier.list.next)
		unregister_mtd_user(&blktrans_notifier);
}

module_exit(mtd_blktrans_exit);

EXPORT_SYMBOL_GPL(register_mtd_blktrans);
EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);

MODULE_AUTHOR("David Woodhouse <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");
Commit	Line	Data
1da177e4	1	/*
1da177e4 LT	2	* (C) 2003 David Woodhouse <[email protected]>
	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>
83144186	17	#include <linux/freezer.h>
1da177e4 LT	18	#include <linux/spinlock.h>
	19	#include <linux/hdreg.h>
	20	#include <linux/init.h>
48b19268	21	#include <linux/mutex.h>
99f9b243	22	#include <linux/kthread.h>
1da177e4	23	#include <asm/uaccess.h>
1da177e4	24
356d70f1	25	#include "mtdcore.h"
1da177e4	26
356d70f1	27	static LIST_HEAD(blktrans_majors);
1da177e4 LT	28
1da177e4 LT	29	struct mtd_blkcore_priv {
3e67fe45	30	struct task_struct *thread;
1da177e4 LT	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
83096ebf	42	block = blk_rq_pos(req) << 9 >> tr->blkshift;
1011c1b9	43	nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
19187672	44
1da177e4 LT	45	buf = req->buffer;
1da177e4 LT	46
4aff5e23	47	if (!blk_fs_request(req))
f06d9a2b	48	return -EIO;
1da177e4	49
83096ebf TH	50	if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
83096ebf TH	51	get_capacity(req->rq_disk))
f06d9a2b	52	return -EIO;
1da177e4	53
1122a26f CH	54	if (blk_discard_rq(req))
	55	return tr->discard(dev, block, nsect);
	56
1da177e4 LT	57	switch(rq_data_dir(req)) {
1da177e4 LT	58	case READ:
19187672	59	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4	60	if (tr->readsect(dev, block, buf))
f06d9a2b	61	return -EIO;
2d4dc890	62	rq_flush_dcache_pages(req);
f06d9a2b	63	return 0;
1da177e4 LT	64
	65	case WRITE:
	66	if (!tr->writesect)
f06d9a2b	67	return -EIO;
1da177e4	68
2d4dc890	69	rq_flush_dcache_pages(req);
19187672	70	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4	71	if (tr->writesect(dev, block, buf))
f06d9a2b TH	72	return -EIO;
f06d9a2b TH	73	return 0;
1da177e4 LT	74
1da177e4 LT	75	default:
9a292308	76	printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
f06d9a2b	77	return -EIO;
1da177e4 LT	78	}
	79	}
	80
	81	static int mtd_blktrans_thread(void *arg)
	82	{
	83	struct mtd_blktrans_ops *tr = arg;
	84	struct request_queue *rq = tr->blkcore_priv->rq;
1498ada7	85	struct request *req = NULL;
1da177e4 LT	86
1da177e4 LT	87	/* we might get involved when memory gets low, so use PF_MEMALLOC */
83144186	88	current->flags \|= PF_MEMALLOC;
1da177e4	89
1da177e4	90	spin_lock_irq(rq->queue_lock);
1498ada7	91
3e67fe45	92	while (!kthread_should_stop()) {
1da177e4	93	struct mtd_blktrans_dev *dev;
f06d9a2b	94	int res;
1da177e4	95
9934c8c0	96	if (!req && !(req = blk_fetch_request(rq))) {
1da177e4	97	set_current_state(TASK_INTERRUPTIBLE);
1da177e4	98	spin_unlock_irq(rq->queue_lock);
1da177e4	99	schedule();
1da177e4	100	spin_lock_irq(rq->queue_lock);
1da177e4 LT	101	continue;
	102	}
	103
	104	dev = req->rq_disk->private_data;
	105	tr = dev->tr;
	106
	107	spin_unlock_irq(rq->queue_lock);
	108
48b19268	109	mutex_lock(&dev->lock);
1da177e4	110	res = do_blktrans_request(tr, dev, req);
48b19268	111	mutex_unlock(&dev->lock);
1da177e4 LT	112
	113	spin_lock_irq(rq->queue_lock);
	114
1498ada7 TH	115	if (!__blk_end_request_cur(req, res))
1498ada7 TH	116	req = NULL;
1da177e4	117	}
1498ada7 TH	118
	119	if (req)
	120	__blk_end_request_all(req, -EIO);
	121
1da177e4 LT	122	spin_unlock_irq(rq->queue_lock);
1da177e4 LT	123
3e67fe45	124	return 0;
1da177e4 LT	125	}
	126
	127	static void mtd_blktrans_request(struct request_queue *rq)
	128	{
	129	struct mtd_blktrans_ops *tr = rq->queuedata;
3e67fe45	130	wake_up_process(tr->blkcore_priv->thread);
1da177e4 LT	131	}
	132
	133
af0e2a0a	134	static int blktrans_open(struct block_device *bdev, fmode_t mode)
1da177e4	135	{
af0e2a0a AV	136	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
af0e2a0a AV	137	struct mtd_blktrans_ops *tr = dev->tr;
1da177e4 LT	138	int ret = -ENODEV;
1da177e4 LT	139
8022c13c	140	if (!get_mtd_device(NULL, dev->mtd->index))
1da177e4 LT	141	goto out;
	142
	143	if (!try_module_get(tr->owner))
	144	goto out_tr;
	145
97894cda	146	/* FIXME: Locking. A hot pluggable device can go away
1da177e4 LT	147	(del_mtd_device can be called for it) without its module
	148	being unloaded. */
	149	dev->mtd->usecount++;
	150
	151	ret = 0;
	152	if (tr->open && (ret = tr->open(dev))) {
	153	dev->mtd->usecount--;
8022c13c	154	put_mtd_device(dev->mtd);
1da177e4 LT	155	out_tr:
	156	module_put(tr->owner);
	157	}
	158	out:
	159	return ret;
	160	}
	161
af0e2a0a	162	static int blktrans_release(struct gendisk *disk, fmode_t mode)
1da177e4	163	{
af0e2a0a AV	164	struct mtd_blktrans_dev *dev = disk->private_data;
af0e2a0a AV	165	struct mtd_blktrans_ops *tr = dev->tr;
1da177e4 LT	166	int ret = 0;
1da177e4 LT	167
1da177e4 LT	168	if (tr->release)
	169	ret = tr->release(dev);
	170
	171	if (!ret) {
	172	dev->mtd->usecount--;
8022c13c	173	put_mtd_device(dev->mtd);
1da177e4 LT	174	module_put(tr->owner);
	175	}
	176
	177	return ret;
	178	}
	179
a885c8c4 CH	180	static int blktrans_getgeo(struct block_device bdev, struct hd_geometry geo)
	181	{
	182	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
	183
	184	if (dev->tr->getgeo)
	185	return dev->tr->getgeo(dev, geo);
	186	return -ENOTTY;
	187	}
1da177e4	188
af0e2a0a	189	static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
1da177e4 LT	190	unsigned int cmd, unsigned long arg)
1da177e4 LT	191	{
af0e2a0a	192	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
1da177e4 LT	193	struct mtd_blktrans_ops *tr = dev->tr;
	194
	195	switch (cmd) {
	196	case BLKFLSBUF:
	197	if (tr->flush)
	198	return tr->flush(dev);
	199	/* The core code did the work, we had nothing to do. */
	200	return 0;
1da177e4 LT	201	default:
	202	return -ENOTTY;
	203	}
	204	}
	205
83d5cde4	206	static const struct block_device_operations mtd_blktrans_ops = {
1da177e4	207	.owner = THIS_MODULE,
af0e2a0a AV	208	.open = blktrans_open,
	209	.release = blktrans_release,
	210	.locked_ioctl = blktrans_ioctl,
a885c8c4	211	.getgeo = blktrans_getgeo,
1da177e4 LT	212	};
	213
	214	int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
	215	{
	216	struct mtd_blktrans_ops *tr = new->tr;
71a928c0	217	struct mtd_blktrans_dev *d;
1da177e4 LT	218	int last_devnum = -1;
	219	struct gendisk *gd;
	220
b3561ea9	221	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	222	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	223	BUG();
	224	}
	225
71a928c0	226	list_for_each_entry(d, &tr->devs, list) {
1da177e4 LT	227	if (new->devnum == -1) {
	228	/* Use first free number */
	229	if (d->devnum != last_devnum+1) {
	230	/* Found a free devnum. Plug it in here */
	231	new->devnum = last_devnum+1;
	232	list_add_tail(&new->list, &d->list);
	233	goto added;
	234	}
	235	} else if (d->devnum == new->devnum) {
	236	/* Required number taken */
	237	return -EBUSY;
	238	} else if (d->devnum > new->devnum) {
	239	/* Required number was free */
	240	list_add_tail(&new->list, &d->list);
	241	goto added;
97894cda	242	}
1da177e4 LT	243	last_devnum = d->devnum;
	244	}
	245	if (new->devnum == -1)
	246	new->devnum = last_devnum+1;
	247
	248	if ((new->devnum << tr->part_bits) > 256) {
	249	return -EBUSY;
	250	}
	251
1da177e4 LT	252	list_add_tail(&new->list, &tr->devs);
1da177e4 LT	253	added:
ce37ab42	254	mutex_init(&new->lock);
1da177e4 LT	255	if (!tr->writesect)
	256	new->readonly = 1;
	257
	258	gd = alloc_disk(1 << tr->part_bits);
	259	if (!gd) {
	260	list_del(&new->list);
	261	return -ENOMEM;
	262	}
	263	gd->major = tr->major;
	264	gd->first_minor = (new->devnum) << tr->part_bits;
	265	gd->fops = &mtd_blktrans_ops;
97894cda	266
65a8de36 TP	267	if (tr->part_bits)
	268	if (new->devnum < 26)
	269	snprintf(gd->disk_name, sizeof(gd->disk_name),
	270	"%s%c", tr->name, 'a' + new->devnum);
	271	else
	272	snprintf(gd->disk_name, sizeof(gd->disk_name),
	273	"%s%c%c", tr->name,
	274	'a' - 1 + new->devnum / 26,
	275	'a' + new->devnum % 26);
	276	else
	277	snprintf(gd->disk_name, sizeof(gd->disk_name),
	278	"%s%d", tr->name, new->devnum);
1da177e4 LT	279
	280	/* 2.5 has capacity in units of 512 bytes while still
	281	having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
19187672	282	set_capacity(gd, (new->size * tr->blksize) >> 9);
1da177e4 LT	283
	284	gd->private_data = new;
	285	new->blkcore_priv = gd;
	286	gd->queue = tr->blkcore_priv->rq;
d694846b	287	gd->driverfs_dev = &new->mtd->dev;
1da177e4 LT	288
	289	if (new->readonly)
	290	set_disk_ro(gd, 1);
	291
	292	add_disk(gd);
97894cda	293
1da177e4 LT	294	return 0;
	295	}
	296
	297	int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
	298	{
b3561ea9	299	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	300	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	301	BUG();
	302	}
	303
	304	list_del(&old->list);
	305
	306	del_gendisk(old->blkcore_priv);
	307	put_disk(old->blkcore_priv);
97894cda	308
1da177e4 LT	309	return 0;
	310	}
	311
	312	static void blktrans_notify_remove(struct mtd_info *mtd)
	313	{
71a928c0 CM	314	struct mtd_blktrans_ops *tr;
71a928c0 CM	315	struct mtd_blktrans_dev dev, next;
1da177e4	316
71a928c0 CM	317	list_for_each_entry(tr, &blktrans_majors, list)
71a928c0 CM	318	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4 LT	319	if (dev->mtd == mtd)
1da177e4 LT	320	tr->remove_dev(dev);
1da177e4 LT	321	}
	322
	323	static void blktrans_notify_add(struct mtd_info *mtd)
	324	{
71a928c0	325	struct mtd_blktrans_ops *tr;
1da177e4 LT	326
	327	if (mtd->type == MTD_ABSENT)
	328	return;
	329
71a928c0	330	list_for_each_entry(tr, &blktrans_majors, list)
1da177e4	331	tr->add_mtd(tr, mtd);
1da177e4 LT	332	}
	333
	334	static struct mtd_notifier blktrans_notifier = {
	335	.add = blktrans_notify_add,
	336	.remove = blktrans_notify_remove,
	337	};
97894cda	338
1da177e4 LT	339	int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
	340	{
	341	int ret, i;
	342
97894cda	343	/* Register the notifier if/when the first device type is
1da177e4 LT	344	registered, to prevent the link/init ordering from fucking
	345	us over. */
	346	if (!blktrans_notifier.list.next)
	347	register_mtd_user(&blktrans_notifier);
	348
95b93a0c	349	tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
1da177e4 LT	350	if (!tr->blkcore_priv)
	351	return -ENOMEM;
	352
48b19268	353	mutex_lock(&mtd_table_mutex);
1da177e4 LT	354
	355	ret = register_blkdev(tr->major, tr->name);
	356	if (ret) {
	357	printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
	358	tr->name, tr->major, ret);
	359	kfree(tr->blkcore_priv);
48b19268	360	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	361	return ret;
	362	}
	363	spin_lock_init(&tr->blkcore_priv->queue_lock);
1da177e4 LT	364
	365	tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
	366	if (!tr->blkcore_priv->rq) {
	367	unregister_blkdev(tr->major, tr->name);
	368	kfree(tr->blkcore_priv);
48b19268	369	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	370	return -ENOMEM;
	371	}
	372
	373	tr->blkcore_priv->rq->queuedata = tr;
e1defc4f	374	blk_queue_logical_block_size(tr->blkcore_priv->rq, tr->blksize);
eae9acd1	375	if (tr->discard)
1122a26f CH	376	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
1122a26f CH	377	tr->blkcore_priv->rq);
eae9acd1	378
19187672	379	tr->blkshift = ffs(tr->blksize) - 1;
1da177e4	380
3e67fe45 CH	381	tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
	382	"%sd", tr->name);
	383	if (IS_ERR(tr->blkcore_priv->thread)) {
2cf3a114	384	int ret = PTR_ERR(tr->blkcore_priv->thread);
1da177e4 LT	385	blk_cleanup_queue(tr->blkcore_priv->rq);
	386	unregister_blkdev(tr->major, tr->name);
	387	kfree(tr->blkcore_priv);
48b19268	388	mutex_unlock(&mtd_table_mutex);
2cf3a114	389	return ret;
97894cda	390	}
1da177e4	391
1da177e4 LT	392	INIT_LIST_HEAD(&tr->devs);
	393	list_add(&tr->list, &blktrans_majors);
	394
	395	for (i=0; i<MAX_MTD_DEVICES; i++) {
	396	if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
	397	tr->add_mtd(tr, mtd_table[i]);
	398	}
	399
48b19268	400	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	401
	402	return 0;
	403	}
	404
	405	int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
	406	{
71a928c0	407	struct mtd_blktrans_dev dev, next;
1da177e4	408
48b19268	409	mutex_lock(&mtd_table_mutex);
1da177e4 LT	410
1da177e4 LT	411	/* Clean up the kernel thread */
3e67fe45	412	kthread_stop(tr->blkcore_priv->thread);
1da177e4 LT	413
	414	/* Remove it from the list of active majors */
	415	list_del(&tr->list);
	416
71a928c0	417	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4	418	tr->remove_dev(dev);
1da177e4	419
1da177e4 LT	420	blk_cleanup_queue(tr->blkcore_priv->rq);
	421	unregister_blkdev(tr->major, tr->name);
	422
48b19268	423	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	424
	425	kfree(tr->blkcore_priv);
	426
373ebfbf	427	BUG_ON(!list_empty(&tr->devs));
1da177e4 LT	428	return 0;
	429	}
	430
	431	static void __exit mtd_blktrans_exit(void)
	432	{
	433	/* No race here -- if someone's currently in register_mtd_blktrans
	434	we're screwed anyway. */
	435	if (blktrans_notifier.list.next)
	436	unregister_mtd_user(&blktrans_notifier);
	437	}
	438
	439	module_exit(mtd_blktrans_exit);
	440
	441	EXPORT_SYMBOL_GPL(register_mtd_blktrans);
	442	EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
	443	EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
	444	EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
	445
	446	MODULE_AUTHOR("David Woodhouse <[email protected]>");
	447	MODULE_LICENSE("GPL");
	448	MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");