[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 <asm/semaphore.h>
#include <asm/uaccess.h>

static LIST_HEAD(blktrans_majors);

extern struct semaphore 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;
	nsect = req->current_nr_sectors;
	buf = req->buffer;

	if (!(req->flags & REQ_CMD))
		return 0;

	if (block + nsect > get_capacity(req->rq_disk))
		return 0;

	switch(rq_data_dir(req)) {
	case READ:
		for (; nsect > 0; nsect--, block++, buf += 512)
			if (tr->readsect(dev, block, buf))
				return 0;
		return 1;

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

		for (; nsect > 0; nsect--, block++, buf += 512)
			if (tr->writesect(dev, block, buf))
				return 0;
		return 1;

	default:
		printk(KERN_NOTICE "Unknown request %ld\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;

	daemonize("%sd", tr->name);

	/* daemonize() doesn't do this for us since some kernel threads
	   actually want to deal with signals. We can't just call
	   exit_sighand() since that'll cause an oops when we finally
	   do exit. */
	spin_lock_irq(&current->sighand->siglock);
	sigfillset(&current->blocked);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	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);

		down(&dev->sem);
		res = do_blktrans_request(tr, dev, req);
		up(&dev->sem);

		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 (!down_trylock(&mtd_table_mutex)) {
		up(&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;
	}

	init_MUTEX(&new->sem);
	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 * new->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 (!down_trylock(&mtd_table_mutex)) {
		up(&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 = kmalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
	if (!tr->blkcore_priv)
		return -ENOMEM;

	memset(tr->blkcore_priv, 0, sizeof(*tr->blkcore_priv));

	down(&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);
		up(&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);
		up(&mtd_table_mutex);
		return -ENOMEM;
	}

	tr->blkcore_priv->rq->queuedata = tr;

	ret = kernel_thread(mtd_blktrans_thread, tr, CLONE_KERNEL);
	if (ret < 0) {
		blk_cleanup_queue(tr->blkcore_priv->rq);
		unregister_blkdev(tr->major, tr->name);
		kfree(tr->blkcore_priv);
		up(&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]);
	}

	up(&mtd_table_mutex);

	return 0;
}

int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
{
	struct list_head *this, *next;

	down(&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);

	up(&mtd_table_mutex);

	kfree(tr->blkcore_priv);

	if (!list_empty(&tr->devs))
		BUG();
	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>
	22	#include <asm/semaphore.h>
	23	#include <asm/uaccess.h>
1da177e4 LT	24
	25	static LIST_HEAD(blktrans_majors);
	26
	27	extern struct semaphore mtd_table_mutex;
	28	extern struct mtd_info *mtd_table[];
	29
	30	struct mtd_blkcore_priv {
	31	struct completion thread_dead;
	32	int exiting;
	33	wait_queue_head_t thread_wq;
	34	struct request_queue *rq;
	35	spinlock_t queue_lock;
	36	};
	37
	38	static int do_blktrans_request(struct mtd_blktrans_ops *tr,
	39	struct mtd_blktrans_dev *dev,
	40	struct request *req)
	41	{
	42	unsigned long block, nsect;
	43	char *buf;
	44
	45	block = req->sector;
	46	nsect = req->current_nr_sectors;
	47	buf = req->buffer;
	48
	49	if (!(req->flags & REQ_CMD))
	50	return 0;
	51
	52	if (block + nsect > get_capacity(req->rq_disk))
	53	return 0;
	54
	55	switch(rq_data_dir(req)) {
	56	case READ:
	57	for (; nsect > 0; nsect--, block++, buf += 512)
	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
	66	for (; nsect > 0; nsect--, block++, buf += 512)
	67	if (tr->writesect(dev, block, buf))
	68	return 0;
	69	return 1;
	70
	71	default:
	72	printk(KERN_NOTICE "Unknown request %ld\n", rq_data_dir(req));
	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 */
	83	current->flags \|= PF_MEMALLOC \| PF_NOFREEZE;
	84
	85	daemonize("%sd", tr->name);
	86
	87	/* daemonize() doesn't do this for us since some kernel threads
97894cda	88	actually want to deal with signals. We can't just call
1da177e4 LT	89	exit_sighand() since that'll cause an oops when we finally
	90	do exit. */
	91	spin_lock_irq(&current->sighand->siglock);
	92	sigfillset(&current->blocked);
	93	recalc_sigpending();
	94	spin_unlock_irq(&current->sighand->siglock);
	95
	96	spin_lock_irq(rq->queue_lock);
97894cda	97
1da177e4 LT	98	while (!tr->blkcore_priv->exiting) {
	99	struct request *req;
	100	struct mtd_blktrans_dev *dev;
	101	int res = 0;
	102	DECLARE_WAITQUEUE(wait, current);
	103
	104	req = elv_next_request(rq);
	105
	106	if (!req) {
	107	add_wait_queue(&tr->blkcore_priv->thread_wq, &wait);
	108	set_current_state(TASK_INTERRUPTIBLE);
	109
	110	spin_unlock_irq(rq->queue_lock);
	111
	112	schedule();
	113	remove_wait_queue(&tr->blkcore_priv->thread_wq, &wait);
	114
	115	spin_lock_irq(rq->queue_lock);
	116
	117	continue;
	118	}
	119
	120	dev = req->rq_disk->private_data;
	121	tr = dev->tr;
	122
	123	spin_unlock_irq(rq->queue_lock);
	124
	125	down(&dev->sem);
	126	res = do_blktrans_request(tr, dev, req);
	127	up(&dev->sem);
	128
	129	spin_lock_irq(rq->queue_lock);
	130
	131	end_request(req, res);
	132	}
	133	spin_unlock_irq(rq->queue_lock);
	134
	135	complete_and_exit(&tr->blkcore_priv->thread_dead, 0);
	136	}
	137
	138	static void mtd_blktrans_request(struct request_queue *rq)
	139	{
	140	struct mtd_blktrans_ops *tr = rq->queuedata;
	141	wake_up(&tr->blkcore_priv->thread_wq);
	142	}
	143
	144
	145	static int blktrans_open(struct inode i, struct file f)
	146	{
	147	struct mtd_blktrans_dev *dev;
	148	struct mtd_blktrans_ops *tr;
	149	int ret = -ENODEV;
	150
	151	dev = i->i_bdev->bd_disk->private_data;
	152	tr = dev->tr;
	153
	154	if (!try_module_get(dev->mtd->owner))
	155	goto out;
	156
	157	if (!try_module_get(tr->owner))
	158	goto out_tr;
	159
97894cda	160	/* FIXME: Locking. A hot pluggable device can go away
1da177e4 LT	161	(del_mtd_device can be called for it) without its module
	162	being unloaded. */
	163	dev->mtd->usecount++;
	164
	165	ret = 0;
	166	if (tr->open && (ret = tr->open(dev))) {
	167	dev->mtd->usecount--;
	168	module_put(dev->mtd->owner);
	169	out_tr:
	170	module_put(tr->owner);
	171	}
	172	out:
	173	return ret;
	174	}
	175
	176	static int blktrans_release(struct inode i, struct file f)
	177	{
	178	struct mtd_blktrans_dev *dev;
	179	struct mtd_blktrans_ops *tr;
	180	int ret = 0;
	181
	182	dev = i->i_bdev->bd_disk->private_data;
	183	tr = dev->tr;
	184
	185	if (tr->release)
	186	ret = tr->release(dev);
	187
	188	if (!ret) {
	189	dev->mtd->usecount--;
	190	module_put(dev->mtd->owner);
	191	module_put(tr->owner);
	192	}
	193
	194	return ret;
	195	}
	196
a885c8c4 CH	197	static int blktrans_getgeo(struct block_device bdev, struct hd_geometry geo)
	198	{
	199	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
	200
	201	if (dev->tr->getgeo)
	202	return dev->tr->getgeo(dev, geo);
	203	return -ENOTTY;
	204	}
1da177e4	205
97894cda	206	static int blktrans_ioctl(struct inode inode, struct file file,
1da177e4 LT	207	unsigned int cmd, unsigned long arg)
	208	{
	209	struct mtd_blktrans_dev *dev = inode->i_bdev->bd_disk->private_data;
	210	struct mtd_blktrans_ops *tr = dev->tr;
	211
	212	switch (cmd) {
	213	case BLKFLSBUF:
	214	if (tr->flush)
	215	return tr->flush(dev);
	216	/* The core code did the work, we had nothing to do. */
	217	return 0;
1da177e4 LT	218	default:
	219	return -ENOTTY;
	220	}
	221	}
	222
	223	struct block_device_operations mtd_blktrans_ops = {
	224	.owner = THIS_MODULE,
	225	.open = blktrans_open,
	226	.release = blktrans_release,
	227	.ioctl = blktrans_ioctl,
a885c8c4	228	.getgeo = blktrans_getgeo,
1da177e4 LT	229	};
	230
	231	int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
	232	{
	233	struct mtd_blktrans_ops *tr = new->tr;
	234	struct list_head *this;
	235	int last_devnum = -1;
	236	struct gendisk *gd;
	237
	238	if (!down_trylock(&mtd_table_mutex)) {
	239	up(&mtd_table_mutex);
	240	BUG();
	241	}
	242
	243	list_for_each(this, &tr->devs) {
	244	struct mtd_blktrans_dev *d = list_entry(this, struct mtd_blktrans_dev, list);
	245	if (new->devnum == -1) {
	246	/* Use first free number */
	247	if (d->devnum != last_devnum+1) {
	248	/* Found a free devnum. Plug it in here */
	249	new->devnum = last_devnum+1;
	250	list_add_tail(&new->list, &d->list);
	251	goto added;
	252	}
	253	} else if (d->devnum == new->devnum) {
	254	/* Required number taken */
	255	return -EBUSY;
	256	} else if (d->devnum > new->devnum) {
	257	/* Required number was free */
	258	list_add_tail(&new->list, &d->list);
	259	goto added;
97894cda	260	}
1da177e4 LT	261	last_devnum = d->devnum;
	262	}
	263	if (new->devnum == -1)
	264	new->devnum = last_devnum+1;
	265
	266	if ((new->devnum << tr->part_bits) > 256) {
	267	return -EBUSY;
	268	}
	269
	270	init_MUTEX(&new->sem);
	271	list_add_tail(&new->list, &tr->devs);
	272	added:
	273	if (!tr->writesect)
	274	new->readonly = 1;
	275
	276	gd = alloc_disk(1 << tr->part_bits);
	277	if (!gd) {
	278	list_del(&new->list);
	279	return -ENOMEM;
	280	}
	281	gd->major = tr->major;
	282	gd->first_minor = (new->devnum) << tr->part_bits;
	283	gd->fops = &mtd_blktrans_ops;
97894cda	284
65a8de36 TP	285	if (tr->part_bits)
	286	if (new->devnum < 26)
	287	snprintf(gd->disk_name, sizeof(gd->disk_name),
	288	"%s%c", tr->name, 'a' + new->devnum);
	289	else
	290	snprintf(gd->disk_name, sizeof(gd->disk_name),
	291	"%s%c%c", tr->name,
	292	'a' - 1 + new->devnum / 26,
	293	'a' + new->devnum % 26);
	294	else
	295	snprintf(gd->disk_name, sizeof(gd->disk_name),
	296	"%s%d", tr->name, new->devnum);
1da177e4 LT	297
	298	/* 2.5 has capacity in units of 512 bytes while still
	299	having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
	300	set_capacity(gd, (new->size * new->blksize) >> 9);
	301
	302	gd->private_data = new;
	303	new->blkcore_priv = gd;
	304	gd->queue = tr->blkcore_priv->rq;
	305
	306	if (new->readonly)
	307	set_disk_ro(gd, 1);
	308
	309	add_disk(gd);
97894cda	310
1da177e4 LT	311	return 0;
	312	}
	313
	314	int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
	315	{
	316	if (!down_trylock(&mtd_table_mutex)) {
	317	up(&mtd_table_mutex);
	318	BUG();
	319	}
	320
	321	list_del(&old->list);
	322
	323	del_gendisk(old->blkcore_priv);
	324	put_disk(old->blkcore_priv);
97894cda	325
1da177e4 LT	326	return 0;
	327	}
	328
	329	static void blktrans_notify_remove(struct mtd_info *mtd)
	330	{
	331	struct list_head this, this2, *next;
	332
	333	list_for_each(this, &blktrans_majors) {
	334	struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
	335
	336	list_for_each_safe(this2, next, &tr->devs) {
	337	struct mtd_blktrans_dev *dev = list_entry(this2, struct mtd_blktrans_dev, list);
	338
	339	if (dev->mtd == mtd)
	340	tr->remove_dev(dev);
	341	}
	342	}
	343	}
	344
	345	static void blktrans_notify_add(struct mtd_info *mtd)
	346	{
	347	struct list_head *this;
	348
	349	if (mtd->type == MTD_ABSENT)
	350	return;
	351
	352	list_for_each(this, &blktrans_majors) {
	353	struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
	354
	355	tr->add_mtd(tr, mtd);
	356	}
	357
	358	}
	359
	360	static struct mtd_notifier blktrans_notifier = {
	361	.add = blktrans_notify_add,
	362	.remove = blktrans_notify_remove,
	363	};
97894cda	364
1da177e4 LT	365	int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
	366	{
	367	int ret, i;
	368
97894cda	369	/* Register the notifier if/when the first device type is
1da177e4 LT	370	registered, to prevent the link/init ordering from fucking
	371	us over. */
	372	if (!blktrans_notifier.list.next)
	373	register_mtd_user(&blktrans_notifier);
	374
	375	tr->blkcore_priv = kmalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
	376	if (!tr->blkcore_priv)
	377	return -ENOMEM;
	378
	379	memset(tr->blkcore_priv, 0, sizeof(*tr->blkcore_priv));
	380
	381	down(&mtd_table_mutex);
	382
	383	ret = register_blkdev(tr->major, tr->name);
	384	if (ret) {
	385	printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
	386	tr->name, tr->major, ret);
	387	kfree(tr->blkcore_priv);
	388	up(&mtd_table_mutex);
	389	return ret;
	390	}
	391	spin_lock_init(&tr->blkcore_priv->queue_lock);
	392	init_completion(&tr->blkcore_priv->thread_dead);
	393	init_waitqueue_head(&tr->blkcore_priv->thread_wq);
	394
	395	tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
	396	if (!tr->blkcore_priv->rq) {
	397	unregister_blkdev(tr->major, tr->name);
	398	kfree(tr->blkcore_priv);
	399	up(&mtd_table_mutex);
	400	return -ENOMEM;
	401	}
	402
	403	tr->blkcore_priv->rq->queuedata = tr;
	404
	405	ret = kernel_thread(mtd_blktrans_thread, tr, CLONE_KERNEL);
	406	if (ret < 0) {
	407	blk_cleanup_queue(tr->blkcore_priv->rq);
	408	unregister_blkdev(tr->major, tr->name);
	409	kfree(tr->blkcore_priv);
	410	up(&mtd_table_mutex);
	411	return ret;
97894cda	412	}
1da177e4	413
1da177e4 LT	414	INIT_LIST_HEAD(&tr->devs);
	415	list_add(&tr->list, &blktrans_majors);
	416
	417	for (i=0; i<MAX_MTD_DEVICES; i++) {
	418	if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
	419	tr->add_mtd(tr, mtd_table[i]);
	420	}
	421
	422	up(&mtd_table_mutex);
	423
	424	return 0;
	425	}
	426
	427	int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
	428	{
	429	struct list_head this, next;
	430
	431	down(&mtd_table_mutex);
	432
	433	/* Clean up the kernel thread */
	434	tr->blkcore_priv->exiting = 1;
	435	wake_up(&tr->blkcore_priv->thread_wq);
	436	wait_for_completion(&tr->blkcore_priv->thread_dead);
	437
	438	/* Remove it from the list of active majors */
	439	list_del(&tr->list);
	440
	441	list_for_each_safe(this, next, &tr->devs) {
	442	struct mtd_blktrans_dev *dev = list_entry(this, struct mtd_blktrans_dev, list);
	443	tr->remove_dev(dev);
	444	}
	445
1da177e4 LT	446	blk_cleanup_queue(tr->blkcore_priv->rq);
	447	unregister_blkdev(tr->major, tr->name);
	448
	449	up(&mtd_table_mutex);
	450
	451	kfree(tr->blkcore_priv);
	452
	453	if (!list_empty(&tr->devs))
	454	BUG();
	455	return 0;
	456	}
	457
	458	static void __exit mtd_blktrans_exit(void)
	459	{
	460	/* No race here -- if someone's currently in register_mtd_blktrans
	461	we're screwed anyway. */
	462	if (blktrans_notifier.list.next)
	463	unregister_mtd_user(&blktrans_notifier);
	464	}
	465
	466	module_exit(mtd_blktrans_exit);
	467
	468	EXPORT_SYMBOL_GPL(register_mtd_blktrans);
	469	EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
	470	EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
	471	EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
	472
	473	MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
	474	MODULE_LICENSE("GPL");
	475	MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");