[deliverable/linux.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/spinlock.h>
#include <linux/hdreg.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/kthread.h>
#include <asm/uaccess.h>

static LIST_HEAD(blktrans_majors);

extern struct mutex mtd_table_mutex;
extern struct mtd_info *mtd_table[];

struct mtd_blkcore_priv {
	struct completion thread_dead;
	int exiting;
	wait_queue_head_t thread_wq;
	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 | PF_NOFREEZE;

	spin_lock_irq(rq->queue_lock);

	while (!tr->blkcore_priv->exiting) {
		struct request *req;
		struct mtd_blktrans_dev *dev;
		int res = 0;
		DECLARE_WAITQUEUE(wait, current);

		req = elv_next_request(rq);

		if (!req) {
			add_wait_queue(&tr->blkcore_priv->thread_wq, &wait);
			set_current_state(TASK_INTERRUPTIBLE);

			spin_unlock_irq(rq->queue_lock);

			schedule();
			remove_wait_queue(&tr->blkcore_priv->thread_wq, &wait);

			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);

	complete_and_exit(&tr->blkcore_priv->thread_dead, 0);
}

static void mtd_blktrans_request(struct request_queue *rq)
{
	struct mtd_blktrans_ops *tr = rq->queuedata;
	wake_up(&tr->blkcore_priv->thread_wq);
}


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;
	}
}

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)
{
	struct task_struct *task;
	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);
	init_completion(&tr->blkcore_priv->thread_dead);
	init_waitqueue_head(&tr->blkcore_priv->thread_wq);

	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;

	task = kthread_run(mtd_blktrans_thread, tr, "%sd", tr->name);
	if (IS_ERR(task)) {
		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(task);
	}

	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 */
	tr->blkcore_priv->exiting = 1;
	wake_up(&tr->blkcore_priv->thread_wq);
	wait_for_completion(&tr->blkcore_priv->thread_dead);

	/* 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>
	19	#include <linux/spinlock.h>
	20	#include <linux/hdreg.h>
	21	#include <linux/init.h>
48b19268	22	#include <linux/mutex.h>
99f9b243	23	#include <linux/kthread.h>
1da177e4	24	#include <asm/uaccess.h>
1da177e4 LT	25
	26	static LIST_HEAD(blktrans_majors);
	27
48b19268	28	extern struct mutex mtd_table_mutex;
1da177e4 LT	29	extern struct mtd_info *mtd_table[];
	30
	31	struct mtd_blkcore_priv {
	32	struct completion thread_dead;
	33	int exiting;
	34	wait_queue_head_t thread_wq;
	35	struct request_queue *rq;
	36	spinlock_t queue_lock;
	37	};
	38
	39	static int do_blktrans_request(struct mtd_blktrans_ops *tr,
	40	struct mtd_blktrans_dev *dev,
	41	struct request *req)
	42	{
	43	unsigned long block, nsect;
	44	char *buf;
	45
19187672 RP	46	block = req->sector << 9 >> tr->blkshift;
	47	nsect = req->current_nr_sectors << 9 >> tr->blkshift;
	48
1da177e4 LT	49	buf = req->buffer;
1da177e4 LT	50
4aff5e23	51	if (!blk_fs_request(req))
1da177e4 LT	52	return 0;
1da177e4 LT	53
19187672	54	if (req->sector + req->current_nr_sectors > get_capacity(req->rq_disk))
1da177e4 LT	55	return 0;
	56
	57	switch(rq_data_dir(req)) {
	58	case READ:
19187672	59	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4 LT	60	if (tr->readsect(dev, block, buf))
	61	return 0;
	62	return 1;
	63
	64	case WRITE:
	65	if (!tr->writesect)
	66	return 0;
	67
19187672	68	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4 LT	69	if (tr->writesect(dev, block, buf))
	70	return 0;
	71	return 1;
	72
	73	default:
9a292308	74	printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
1da177e4 LT	75	return 0;
	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
	84	/* we might get involved when memory gets low, so use PF_MEMALLOC */
	85	current->flags \|= PF_MEMALLOC \| PF_NOFREEZE;
	86
1da177e4	87	spin_lock_irq(rq->queue_lock);
97894cda	88
1da177e4 LT	89	while (!tr->blkcore_priv->exiting) {
	90	struct request *req;
	91	struct mtd_blktrans_dev *dev;
	92	int res = 0;
	93	DECLARE_WAITQUEUE(wait, current);
	94
	95	req = elv_next_request(rq);
	96
	97	if (!req) {
	98	add_wait_queue(&tr->blkcore_priv->thread_wq, &wait);
	99	set_current_state(TASK_INTERRUPTIBLE);
	100
	101	spin_unlock_irq(rq->queue_lock);
	102
	103	schedule();
	104	remove_wait_queue(&tr->blkcore_priv->thread_wq, &wait);
	105
	106	spin_lock_irq(rq->queue_lock);
	107
	108	continue;
	109	}
	110
	111	dev = req->rq_disk->private_data;
	112	tr = dev->tr;
	113
	114	spin_unlock_irq(rq->queue_lock);
	115
48b19268	116	mutex_lock(&dev->lock);
1da177e4	117	res = do_blktrans_request(tr, dev, req);
48b19268	118	mutex_unlock(&dev->lock);
1da177e4 LT	119
	120	spin_lock_irq(rq->queue_lock);
	121
	122	end_request(req, res);
	123	}
	124	spin_unlock_irq(rq->queue_lock);
	125
	126	complete_and_exit(&tr->blkcore_priv->thread_dead, 0);
	127	}
	128
	129	static void mtd_blktrans_request(struct request_queue *rq)
	130	{
	131	struct mtd_blktrans_ops *tr = rq->queuedata;
	132	wake_up(&tr->blkcore_priv->thread_wq);
	133	}
	134
	135
	136	static int blktrans_open(struct inode i, struct file f)
	137	{
	138	struct mtd_blktrans_dev *dev;
	139	struct mtd_blktrans_ops *tr;
	140	int ret = -ENODEV;
	141
	142	dev = i->i_bdev->bd_disk->private_data;
	143	tr = dev->tr;
	144
	145	if (!try_module_get(dev->mtd->owner))
	146	goto out;
	147
	148	if (!try_module_get(tr->owner))
	149	goto out_tr;
	150
97894cda	151	/* FIXME: Locking. A hot pluggable device can go away
1da177e4 LT	152	(del_mtd_device can be called for it) without its module
	153	being unloaded. */
	154	dev->mtd->usecount++;
	155
	156	ret = 0;
	157	if (tr->open && (ret = tr->open(dev))) {
	158	dev->mtd->usecount--;
	159	module_put(dev->mtd->owner);
	160	out_tr:
	161	module_put(tr->owner);
	162	}
	163	out:
	164	return ret;
	165	}
	166
	167	static int blktrans_release(struct inode i, struct file f)
	168	{
	169	struct mtd_blktrans_dev *dev;
	170	struct mtd_blktrans_ops *tr;
	171	int ret = 0;
	172
	173	dev = i->i_bdev->bd_disk->private_data;
	174	tr = dev->tr;
	175
	176	if (tr->release)
	177	ret = tr->release(dev);
	178
	179	if (!ret) {
	180	dev->mtd->usecount--;
	181	module_put(dev->mtd->owner);
	182	module_put(tr->owner);
	183	}
	184
	185	return ret;
	186	}
	187
a885c8c4 CH	188	static int blktrans_getgeo(struct block_device bdev, struct hd_geometry geo)
	189	{
	190	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
	191
	192	if (dev->tr->getgeo)
	193	return dev->tr->getgeo(dev, geo);
	194	return -ENOTTY;
	195	}
1da177e4	196
97894cda	197	static int blktrans_ioctl(struct inode inode, struct file file,
1da177e4 LT	198	unsigned int cmd, unsigned long arg)
	199	{
	200	struct mtd_blktrans_dev *dev = inode->i_bdev->bd_disk->private_data;
	201	struct mtd_blktrans_ops *tr = dev->tr;
	202
	203	switch (cmd) {
	204	case BLKFLSBUF:
	205	if (tr->flush)
	206	return tr->flush(dev);
	207	/* The core code did the work, we had nothing to do. */
	208	return 0;
1da177e4 LT	209	default:
	210	return -ENOTTY;
	211	}
	212	}
	213
	214	struct block_device_operations mtd_blktrans_ops = {
	215	.owner = THIS_MODULE,
	216	.open = blktrans_open,
	217	.release = blktrans_release,
	218	.ioctl = blktrans_ioctl,
a885c8c4	219	.getgeo = blktrans_getgeo,
1da177e4 LT	220	};
	221
	222	int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
	223	{
	224	struct mtd_blktrans_ops *tr = new->tr;
	225	struct list_head *this;
	226	int last_devnum = -1;
	227	struct gendisk *gd;
	228
48b19268 IM	229	if (!!mutex_trylock(&mtd_table_mutex)) {
48b19268 IM	230	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	231	BUG();
	232	}
	233
	234	list_for_each(this, &tr->devs) {
	235	struct mtd_blktrans_dev *d = list_entry(this, struct mtd_blktrans_dev, list);
	236	if (new->devnum == -1) {
	237	/* Use first free number */
	238	if (d->devnum != last_devnum+1) {
	239	/* Found a free devnum. Plug it in here */
	240	new->devnum = last_devnum+1;
	241	list_add_tail(&new->list, &d->list);
	242	goto added;
	243	}
	244	} else if (d->devnum == new->devnum) {
	245	/* Required number taken */
	246	return -EBUSY;
	247	} else if (d->devnum > new->devnum) {
	248	/* Required number was free */
	249	list_add_tail(&new->list, &d->list);
	250	goto added;
97894cda	251	}
1da177e4 LT	252	last_devnum = d->devnum;
	253	}
	254	if (new->devnum == -1)
	255	new->devnum = last_devnum+1;
	256
	257	if ((new->devnum << tr->part_bits) > 256) {
	258	return -EBUSY;
	259	}
	260
48b19268	261	mutex_init(&new->lock);
1da177e4 LT	262	list_add_tail(&new->list, &tr->devs);
	263	added:
	264	if (!tr->writesect)
	265	new->readonly = 1;
	266
	267	gd = alloc_disk(1 << tr->part_bits);
	268	if (!gd) {
	269	list_del(&new->list);
	270	return -ENOMEM;
	271	}
	272	gd->major = tr->major;
	273	gd->first_minor = (new->devnum) << tr->part_bits;
	274	gd->fops = &mtd_blktrans_ops;
97894cda	275
65a8de36 TP	276	if (tr->part_bits)
	277	if (new->devnum < 26)
	278	snprintf(gd->disk_name, sizeof(gd->disk_name),
	279	"%s%c", tr->name, 'a' + new->devnum);
	280	else
	281	snprintf(gd->disk_name, sizeof(gd->disk_name),
	282	"%s%c%c", tr->name,
	283	'a' - 1 + new->devnum / 26,
	284	'a' + new->devnum % 26);
	285	else
	286	snprintf(gd->disk_name, sizeof(gd->disk_name),
	287	"%s%d", tr->name, new->devnum);
1da177e4 LT	288
	289	/* 2.5 has capacity in units of 512 bytes while still
	290	having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
19187672	291	set_capacity(gd, (new->size * tr->blksize) >> 9);
1da177e4 LT	292
	293	gd->private_data = new;
	294	new->blkcore_priv = gd;
	295	gd->queue = tr->blkcore_priv->rq;
	296
	297	if (new->readonly)
	298	set_disk_ro(gd, 1);
	299
	300	add_disk(gd);
97894cda	301
1da177e4 LT	302	return 0;
	303	}
	304
	305	int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
	306	{
48b19268 IM	307	if (!!mutex_trylock(&mtd_table_mutex)) {
48b19268 IM	308	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	309	BUG();
	310	}
	311
	312	list_del(&old->list);
	313
	314	del_gendisk(old->blkcore_priv);
	315	put_disk(old->blkcore_priv);
97894cda	316
1da177e4 LT	317	return 0;
	318	}
	319
	320	static void blktrans_notify_remove(struct mtd_info *mtd)
	321	{
	322	struct list_head this, this2, *next;
	323
	324	list_for_each(this, &blktrans_majors) {
	325	struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
	326
	327	list_for_each_safe(this2, next, &tr->devs) {
	328	struct mtd_blktrans_dev *dev = list_entry(this2, struct mtd_blktrans_dev, list);
	329
	330	if (dev->mtd == mtd)
	331	tr->remove_dev(dev);
	332	}
	333	}
	334	}
	335
	336	static void blktrans_notify_add(struct mtd_info *mtd)
	337	{
	338	struct list_head *this;
	339
	340	if (mtd->type == MTD_ABSENT)
	341	return;
	342
	343	list_for_each(this, &blktrans_majors) {
	344	struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
	345
	346	tr->add_mtd(tr, mtd);
	347	}
	348
	349	}
	350
	351	static struct mtd_notifier blktrans_notifier = {
	352	.add = blktrans_notify_add,
	353	.remove = blktrans_notify_remove,
	354	};
97894cda	355
1da177e4 LT	356	int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
1da177e4 LT	357	{
99f9b243	358	struct task_struct *task;
1da177e4 LT	359	int ret, i;
1da177e4 LT	360
97894cda	361	/* Register the notifier if/when the first device type is
1da177e4 LT	362	registered, to prevent the link/init ordering from fucking
	363	us over. */
	364	if (!blktrans_notifier.list.next)
	365	register_mtd_user(&blktrans_notifier);
	366
95b93a0c	367	tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
1da177e4 LT	368	if (!tr->blkcore_priv)
	369	return -ENOMEM;
	370
48b19268	371	mutex_lock(&mtd_table_mutex);
1da177e4 LT	372
	373	ret = register_blkdev(tr->major, tr->name);
	374	if (ret) {
	375	printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
	376	tr->name, tr->major, ret);
	377	kfree(tr->blkcore_priv);
48b19268	378	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	379	return ret;
	380	}
	381	spin_lock_init(&tr->blkcore_priv->queue_lock);
	382	init_completion(&tr->blkcore_priv->thread_dead);
	383	init_waitqueue_head(&tr->blkcore_priv->thread_wq);
	384
	385	tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
	386	if (!tr->blkcore_priv->rq) {
	387	unregister_blkdev(tr->major, tr->name);
	388	kfree(tr->blkcore_priv);
48b19268	389	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	390	return -ENOMEM;
	391	}
	392
	393	tr->blkcore_priv->rq->queuedata = tr;
19187672 RP	394	blk_queue_hardsect_size(tr->blkcore_priv->rq, tr->blksize);
19187672 RP	395	tr->blkshift = ffs(tr->blksize) - 1;
1da177e4	396
99f9b243 EB	397	task = kthread_run(mtd_blktrans_thread, tr, "%sd", tr->name);
99f9b243 EB	398	if (IS_ERR(task)) {
1da177e4 LT	399	blk_cleanup_queue(tr->blkcore_priv->rq);
	400	unregister_blkdev(tr->major, tr->name);
	401	kfree(tr->blkcore_priv);
48b19268	402	mutex_unlock(&mtd_table_mutex);
99f9b243	403	return PTR_ERR(task);
97894cda	404	}
1da177e4	405
1da177e4 LT	406	INIT_LIST_HEAD(&tr->devs);
	407	list_add(&tr->list, &blktrans_majors);
	408
	409	for (i=0; i<MAX_MTD_DEVICES; i++) {
	410	if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
	411	tr->add_mtd(tr, mtd_table[i]);
	412	}
	413
48b19268	414	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	415
	416	return 0;
	417	}
	418
	419	int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
	420	{
	421	struct list_head this, next;
	422
48b19268	423	mutex_lock(&mtd_table_mutex);
1da177e4 LT	424
	425	/* Clean up the kernel thread */
	426	tr->blkcore_priv->exiting = 1;
	427	wake_up(&tr->blkcore_priv->thread_wq);
	428	wait_for_completion(&tr->blkcore_priv->thread_dead);
	429
	430	/* Remove it from the list of active majors */
	431	list_del(&tr->list);
	432
	433	list_for_each_safe(this, next, &tr->devs) {
	434	struct mtd_blktrans_dev *dev = list_entry(this, struct mtd_blktrans_dev, list);
	435	tr->remove_dev(dev);
	436	}
	437
1da177e4 LT	438	blk_cleanup_queue(tr->blkcore_priv->rq);
	439	unregister_blkdev(tr->major, tr->name);
	440
48b19268	441	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	442
	443	kfree(tr->blkcore_priv);
	444
373ebfbf	445	BUG_ON(!list_empty(&tr->devs));
1da177e4 LT	446	return 0;
	447	}
	448
	449	static void __exit mtd_blktrans_exit(void)
	450	{
	451	/* No race here -- if someone's currently in register_mtd_blktrans
	452	we're screwed anyway. */
	453	if (blktrans_notifier.list.next)
	454	unregister_mtd_user(&blktrans_notifier);
	455	}
	456
	457	module_exit(mtd_blktrans_exit);
	458
	459	EXPORT_SYMBOL_GPL(register_mtd_blktrans);
	460	EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
	461	EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
	462	EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
	463
	464	MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
	465	MODULE_LICENSE("GPL");
	466	MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");