[linux-2.6-block.git] / drivers / mtd / mtd_blkdevs.c

/*
 * $Id: mtd_blkdevs.c,v 1.27 2005/11/07 11:14:20 gleixner Exp $
 *
 * (C) 2003 David Woodhouse <dwmw2@infradead.org>
 *
 * 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 = req->sector << 9 >> tr->blkshift;
	nsect = req->current_nr_sectors << 9 >> tr->blkshift;

	buf = req->buffer;

	if (!blk_fs_request(req))
		return 0;

	if (req->sector + req->current_nr_sectors > get_capacity(req->rq_disk))
		return 0;

	switch(rq_data_dir(req)) {
	case READ:
		for (; nsect > 0; nsect--, block++, buf += tr->blksize)
			if (tr->readsect(dev, block, buf))
				return 0;
		return 1;

	case WRITE:
		if (!tr->writesect)
			return 0;

		for (; nsect > 0; nsect--, block++, buf += tr->blksize)
			if (tr->writesect(dev, block, buf))
				return 0;
		return 1;

	default:
		printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
		return 0;
	}
}

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

	/* 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 request *req;
		struct mtd_blktrans_dev *dev;
		int res = 0;

		req = elv_next_request(rq);

		if (!req) {
			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);

		end_request(req, res);
	}
	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 inode *i, struct file *f)
{
	struct mtd_blktrans_dev *dev;
	struct mtd_blktrans_ops *tr;
	int ret = -ENODEV;

	dev = i->i_bdev->bd_disk->private_data;
	tr = dev->tr;

	if (!try_module_get(dev->mtd->owner))
		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--;
		module_put(dev->mtd->owner);
	out_tr:
		module_put(tr->owner);
	}
 out:
	return ret;
}

static int blktrans_release(struct inode *i, struct file *f)
{
	struct mtd_blktrans_dev *dev;
	struct mtd_blktrans_ops *tr;
	int ret = 0;

	dev = i->i_bdev->bd_disk->private_data;
	tr = dev->tr;

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

	if (!ret) {
		dev->mtd->usecount--;
		module_put(dev->mtd->owner);
		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 inode *inode, struct file *file,
			      unsigned int cmd, unsigned long arg)
{
	struct mtd_blktrans_dev *dev = inode->i_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 struct block_device_operations mtd_blktrans_ops = {
	.owner		= THIS_MODULE,
	.open		= blktrans_open,
	.release	= blktrans_release,
	.ioctl		= blktrans_ioctl,
	.getgeo		= blktrans_getgeo,
};

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

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

	list_for_each(this, &tr->devs) {
		struct mtd_blktrans_dev *d = list_entry(this, struct mtd_blktrans_dev, 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;
	}

	mutex_init(&new->lock);
	list_add_tail(&new->list, &tr->devs);
 added:
	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;

	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 list_head *this, *this2, *next;

	list_for_each(this, &blktrans_majors) {
		struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);

		list_for_each_safe(this2, next, &tr->devs) {
			struct mtd_blktrans_dev *dev = list_entry(this2, struct mtd_blktrans_dev, list);

			if (dev->mtd == mtd)
				tr->remove_dev(dev);
		}
	}
}

static void blktrans_notify_add(struct mtd_info *mtd)
{
	struct list_head *this;

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

	list_for_each(this, &blktrans_majors) {
		struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, 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_hardsect_size(tr->blkcore_priv->rq, tr->blksize);
	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)) {
		blk_cleanup_queue(tr->blkcore_priv->rq);
		unregister_blkdev(tr->major, tr->name);
		kfree(tr->blkcore_priv);
		mutex_unlock(&mtd_table_mutex);
		return PTR_ERR(tr->blkcore_priv->thread);
	}

	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 list_head *this, *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_safe(this, next, &tr->devs) {
		struct mtd_blktrans_dev *dev = list_entry(this, struct mtd_blktrans_dev, 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 <dwmw2@infradead.org>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");
Commit	Line	Data
1da177e4	1	/*
97894cda	2	* $Id: mtd_blkdevs.c,v 1.27 2005/11/07 11:14:20 gleixner 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>
83144186	19	#include <linux/freezer.h>
1da177e4 LT	20	#include <linux/spinlock.h>
	21	#include <linux/hdreg.h>
	22	#include <linux/init.h>
48b19268	23	#include <linux/mutex.h>
99f9b243	24	#include <linux/kthread.h>
1da177e4	25	#include <asm/uaccess.h>
1da177e4	26
356d70f1	27	#include "mtdcore.h"
1da177e4	28
356d70f1	29	static LIST_HEAD(blktrans_majors);
1da177e4 LT	30
1da177e4 LT	31	struct mtd_blkcore_priv {
3e67fe45	32	struct task_struct *thread;
1da177e4 LT	33	struct request_queue *rq;
	34	spinlock_t queue_lock;
	35	};
	36
	37	static int do_blktrans_request(struct mtd_blktrans_ops *tr,
	38	struct mtd_blktrans_dev *dev,
	39	struct request *req)
	40	{
	41	unsigned long block, nsect;
	42	char *buf;
	43
19187672 RP	44	block = req->sector << 9 >> tr->blkshift;
	45	nsect = req->current_nr_sectors << 9 >> tr->blkshift;
	46
1da177e4 LT	47	buf = req->buffer;
1da177e4 LT	48
4aff5e23	49	if (!blk_fs_request(req))
1da177e4 LT	50	return 0;
1da177e4 LT	51
19187672	52	if (req->sector + req->current_nr_sectors > get_capacity(req->rq_disk))
1da177e4 LT	53	return 0;
	54
	55	switch(rq_data_dir(req)) {
	56	case READ:
19187672	57	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4 LT	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
19187672	66	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4 LT	67	if (tr->writesect(dev, block, buf))
	68	return 0;
	69	return 1;
	70
	71	default:
9a292308	72	printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
1da177e4 LT	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 */
83144186	83	current->flags \|= PF_MEMALLOC;
1da177e4	84
1da177e4	85	spin_lock_irq(rq->queue_lock);
3e67fe45	86	while (!kthread_should_stop()) {
1da177e4 LT	87	struct request *req;
	88	struct mtd_blktrans_dev *dev;
	89	int res = 0;
1da177e4 LT	90
	91	req = elv_next_request(rq);
	92
	93	if (!req) {
1da177e4	94	set_current_state(TASK_INTERRUPTIBLE);
1da177e4	95	spin_unlock_irq(rq->queue_lock);
1da177e4	96	schedule();
1da177e4	97	spin_lock_irq(rq->queue_lock);
1da177e4 LT	98	continue;
	99	}
	100
	101	dev = req->rq_disk->private_data;
	102	tr = dev->tr;
	103
	104	spin_unlock_irq(rq->queue_lock);
	105
48b19268	106	mutex_lock(&dev->lock);
1da177e4	107	res = do_blktrans_request(tr, dev, req);
48b19268	108	mutex_unlock(&dev->lock);
1da177e4 LT	109
	110	spin_lock_irq(rq->queue_lock);
	111
	112	end_request(req, res);
	113	}
	114	spin_unlock_irq(rq->queue_lock);
	115
3e67fe45	116	return 0;
1da177e4 LT	117	}
	118
	119	static void mtd_blktrans_request(struct request_queue *rq)
	120	{
	121	struct mtd_blktrans_ops *tr = rq->queuedata;
3e67fe45	122	wake_up_process(tr->blkcore_priv->thread);
1da177e4 LT	123	}
	124
	125
	126	static int blktrans_open(struct inode i, struct file f)
	127	{
	128	struct mtd_blktrans_dev *dev;
	129	struct mtd_blktrans_ops *tr;
	130	int ret = -ENODEV;
	131
	132	dev = i->i_bdev->bd_disk->private_data;
	133	tr = dev->tr;
	134
	135	if (!try_module_get(dev->mtd->owner))
	136	goto out;
	137
	138	if (!try_module_get(tr->owner))
	139	goto out_tr;
	140
97894cda	141	/* FIXME: Locking. A hot pluggable device can go away
1da177e4 LT	142	(del_mtd_device can be called for it) without its module
	143	being unloaded. */
	144	dev->mtd->usecount++;
	145
	146	ret = 0;
	147	if (tr->open && (ret = tr->open(dev))) {
	148	dev->mtd->usecount--;
	149	module_put(dev->mtd->owner);
	150	out_tr:
	151	module_put(tr->owner);
	152	}
	153	out:
	154	return ret;
	155	}
	156
	157	static int blktrans_release(struct inode i, struct file f)
	158	{
	159	struct mtd_blktrans_dev *dev;
	160	struct mtd_blktrans_ops *tr;
	161	int ret = 0;
	162
	163	dev = i->i_bdev->bd_disk->private_data;
	164	tr = dev->tr;
	165
	166	if (tr->release)
	167	ret = tr->release(dev);
	168
	169	if (!ret) {
	170	dev->mtd->usecount--;
	171	module_put(dev->mtd->owner);
	172	module_put(tr->owner);
	173	}
	174
	175	return ret;
	176	}
	177
a885c8c4 CH	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	}
1da177e4	186
97894cda	187	static int blktrans_ioctl(struct inode inode, struct file file,
1da177e4 LT	188	unsigned int cmd, unsigned long arg)
	189	{
	190	struct mtd_blktrans_dev *dev = inode->i_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;
1da177e4 LT	199	default:
	200	return -ENOTTY;
	201	}
	202	}
	203
8f026f75	204	static struct block_device_operations mtd_blktrans_ops = {
1da177e4 LT	205	.owner = THIS_MODULE,
	206	.open = blktrans_open,
	207	.release = blktrans_release,
	208	.ioctl = blktrans_ioctl,
a885c8c4	209	.getgeo = blktrans_getgeo,
1da177e4 LT	210	};
	211
	212	int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
	213	{
	214	struct mtd_blktrans_ops *tr = new->tr;
	215	struct list_head *this;
	216	int last_devnum = -1;
	217	struct gendisk *gd;
	218
b3561ea9	219	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	220	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	221	BUG();
	222	}
	223
	224	list_for_each(this, &tr->devs) {
	225	struct mtd_blktrans_dev *d = list_entry(this, struct mtd_blktrans_dev, list);
	226	if (new->devnum == -1) {
	227	/* Use first free number */
	228	if (d->devnum != last_devnum+1) {
	229	/* Found a free devnum. Plug it in here */
	230	new->devnum = last_devnum+1;
	231	list_add_tail(&new->list, &d->list);
	232	goto added;
	233	}
	234	} else if (d->devnum == new->devnum) {
	235	/* Required number taken */
	236	return -EBUSY;
	237	} else if (d->devnum > new->devnum) {
	238	/* Required number was free */
	239	list_add_tail(&new->list, &d->list);
	240	goto added;
97894cda	241	}
1da177e4 LT	242	last_devnum = d->devnum;
	243	}
	244	if (new->devnum == -1)
	245	new->devnum = last_devnum+1;
	246
	247	if ((new->devnum << tr->part_bits) > 256) {
	248	return -EBUSY;
	249	}
	250
48b19268	251	mutex_init(&new->lock);
1da177e4 LT	252	list_add_tail(&new->list, &tr->devs);
	253	added:
	254	if (!tr->writesect)
	255	new->readonly = 1;
	256
	257	gd = alloc_disk(1 << tr->part_bits);
	258	if (!gd) {
	259	list_del(&new->list);
	260	return -ENOMEM;
	261	}
	262	gd->major = tr->major;
	263	gd->first_minor = (new->devnum) << tr->part_bits;
	264	gd->fops = &mtd_blktrans_ops;
97894cda	265
65a8de36 TP	266	if (tr->part_bits)
	267	if (new->devnum < 26)
	268	snprintf(gd->disk_name, sizeof(gd->disk_name),
	269	"%s%c", tr->name, 'a' + new->devnum);
	270	else
	271	snprintf(gd->disk_name, sizeof(gd->disk_name),
	272	"%s%c%c", tr->name,
	273	'a' - 1 + new->devnum / 26,
	274	'a' + new->devnum % 26);
	275	else
	276	snprintf(gd->disk_name, sizeof(gd->disk_name),
	277	"%s%d", tr->name, new->devnum);
1da177e4 LT	278
	279	/* 2.5 has capacity in units of 512 bytes while still
	280	having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
19187672	281	set_capacity(gd, (new->size * tr->blksize) >> 9);
1da177e4 LT	282
	283	gd->private_data = new;
	284	new->blkcore_priv = gd;
	285	gd->queue = tr->blkcore_priv->rq;
	286
	287	if (new->readonly)
	288	set_disk_ro(gd, 1);
	289
	290	add_disk(gd);
97894cda	291
1da177e4 LT	292	return 0;
	293	}
	294
	295	int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
	296	{
b3561ea9	297	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	298	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	299	BUG();
	300	}
	301
	302	list_del(&old->list);
	303
	304	del_gendisk(old->blkcore_priv);
	305	put_disk(old->blkcore_priv);
97894cda	306
1da177e4 LT	307	return 0;
	308	}
	309
	310	static void blktrans_notify_remove(struct mtd_info *mtd)
	311	{
	312	struct list_head this, this2, *next;
	313
	314	list_for_each(this, &blktrans_majors) {
	315	struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
	316
	317	list_for_each_safe(this2, next, &tr->devs) {
	318	struct mtd_blktrans_dev *dev = list_entry(this2, struct mtd_blktrans_dev, list);
	319
	320	if (dev->mtd == mtd)
	321	tr->remove_dev(dev);
	322	}
	323	}
	324	}
	325
	326	static void blktrans_notify_add(struct mtd_info *mtd)
	327	{
	328	struct list_head *this;
	329
	330	if (mtd->type == MTD_ABSENT)
	331	return;
	332
	333	list_for_each(this, &blktrans_majors) {
	334	struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
	335
	336	tr->add_mtd(tr, mtd);
	337	}
	338
	339	}
	340
	341	static struct mtd_notifier blktrans_notifier = {
	342	.add = blktrans_notify_add,
	343	.remove = blktrans_notify_remove,
	344	};
97894cda	345
1da177e4 LT	346	int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
	347	{
	348	int ret, i;
	349
97894cda	350	/* Register the notifier if/when the first device type is
1da177e4 LT	351	registered, to prevent the link/init ordering from fucking
	352	us over. */
	353	if (!blktrans_notifier.list.next)
	354	register_mtd_user(&blktrans_notifier);
	355
95b93a0c	356	tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
1da177e4 LT	357	if (!tr->blkcore_priv)
	358	return -ENOMEM;
	359
48b19268	360	mutex_lock(&mtd_table_mutex);
1da177e4 LT	361
	362	ret = register_blkdev(tr->major, tr->name);
	363	if (ret) {
	364	printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
	365	tr->name, tr->major, ret);
	366	kfree(tr->blkcore_priv);
48b19268	367	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	368	return ret;
	369	}
	370	spin_lock_init(&tr->blkcore_priv->queue_lock);
1da177e4 LT	371
	372	tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
	373	if (!tr->blkcore_priv->rq) {
	374	unregister_blkdev(tr->major, tr->name);
	375	kfree(tr->blkcore_priv);
48b19268	376	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	377	return -ENOMEM;
	378	}
	379
	380	tr->blkcore_priv->rq->queuedata = tr;
19187672 RP	381	blk_queue_hardsect_size(tr->blkcore_priv->rq, tr->blksize);
19187672 RP	382	tr->blkshift = ffs(tr->blksize) - 1;
1da177e4	383
3e67fe45 CH	384	tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
	385	"%sd", tr->name);
	386	if (IS_ERR(tr->blkcore_priv->thread)) {
1da177e4 LT	387	blk_cleanup_queue(tr->blkcore_priv->rq);
	388	unregister_blkdev(tr->major, tr->name);
	389	kfree(tr->blkcore_priv);
48b19268	390	mutex_unlock(&mtd_table_mutex);
3e67fe45	391	return PTR_ERR(tr->blkcore_priv->thread);
97894cda	392	}
1da177e4	393
1da177e4 LT	394	INIT_LIST_HEAD(&tr->devs);
	395	list_add(&tr->list, &blktrans_majors);
	396
	397	for (i=0; i<MAX_MTD_DEVICES; i++) {
	398	if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
	399	tr->add_mtd(tr, mtd_table[i]);
	400	}
	401
48b19268	402	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	403
	404	return 0;
	405	}
	406
	407	int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
	408	{
	409	struct list_head this, next;
	410
48b19268	411	mutex_lock(&mtd_table_mutex);
1da177e4 LT	412
1da177e4 LT	413	/* Clean up the kernel thread */
3e67fe45	414	kthread_stop(tr->blkcore_priv->thread);
1da177e4 LT	415
	416	/* Remove it from the list of active majors */
	417	list_del(&tr->list);
	418
	419	list_for_each_safe(this, next, &tr->devs) {
	420	struct mtd_blktrans_dev *dev = list_entry(this, struct mtd_blktrans_dev, list);
	421	tr->remove_dev(dev);
	422	}
	423
1da177e4 LT	424	blk_cleanup_queue(tr->blkcore_priv->rq);
	425	unregister_blkdev(tr->major, tr->name);
	426
48b19268	427	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	428
	429	kfree(tr->blkcore_priv);
	430
373ebfbf	431	BUG_ON(!list_empty(&tr->devs));
1da177e4 LT	432	return 0;
	433	}
	434
	435	static void __exit mtd_blktrans_exit(void)
	436	{
	437	/* No race here -- if someone's currently in register_mtd_blktrans
	438	we're screwed anyway. */
	439	if (blktrans_notifier.list.next)
	440	unregister_mtd_user(&blktrans_notifier);
	441	}
	442
	443	module_exit(mtd_blktrans_exit);
	444
	445	EXPORT_SYMBOL_GPL(register_mtd_blktrans);
	446	EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
	447	EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
	448	EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
	449
	450	MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
	451	MODULE_LICENSE("GPL");
	452	MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");