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

/*
 * (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 blktrans_discard_request(struct request_queue *q,
				    struct request *req)
{
	req->cmd_type = REQ_TYPE_LINUX_BLOCK;
	req->cmd[0] = REQ_LB_OP_DISCARD;
	return 0;
}

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 (req->cmd_type == REQ_TYPE_LINUX_BLOCK &&
	    req->cmd[0] == REQ_LB_OP_DISCARD)
		return tr->discard(dev, block, nsect);

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

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

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

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

		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 (!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 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--;
		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 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 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.parent;

	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)
		blk_queue_set_discard(tr->blkcore_priv->rq,
				      blktrans_discard_request);

	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 <dwmw2@infradead.org>");
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 <dwmw2@infradead.org>
	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
eae9acd1 DW	35	static int blktrans_discard_request(struct request_queue *q,
	36	struct request *req)
	37	{
	38	req->cmd_type = REQ_TYPE_LINUX_BLOCK;
	39	req->cmd[0] = REQ_LB_OP_DISCARD;
	40	return 0;
	41	}
	42
1da177e4 LT	43	static int do_blktrans_request(struct mtd_blktrans_ops *tr,
	44	struct mtd_blktrans_dev *dev,
	45	struct request *req)
	46	{
	47	unsigned long block, nsect;
	48	char *buf;
	49
83096ebf	50	block = blk_rq_pos(req) << 9 >> tr->blkshift;
1011c1b9	51	nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
19187672	52
1da177e4 LT	53	buf = req->buffer;
1da177e4 LT	54
eae9acd1 DW	55	if (req->cmd_type == REQ_TYPE_LINUX_BLOCK &&
eae9acd1 DW	56	req->cmd[0] == REQ_LB_OP_DISCARD)
f06d9a2b	57	return tr->discard(dev, block, nsect);
eae9acd1	58
4aff5e23	59	if (!blk_fs_request(req))
f06d9a2b	60	return -EIO;
1da177e4	61
83096ebf TH	62	if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
83096ebf TH	63	get_capacity(req->rq_disk))
f06d9a2b	64	return -EIO;
1da177e4 LT	65
	66	switch(rq_data_dir(req)) {
	67	case READ:
19187672	68	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4	69	if (tr->readsect(dev, block, buf))
f06d9a2b TH	70	return -EIO;
f06d9a2b TH	71	return 0;
1da177e4 LT	72
	73	case WRITE:
	74	if (!tr->writesect)
f06d9a2b	75	return -EIO;
1da177e4	76
19187672	77	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4	78	if (tr->writesect(dev, block, buf))
f06d9a2b TH	79	return -EIO;
f06d9a2b TH	80	return 0;
1da177e4 LT	81
1da177e4 LT	82	default:
9a292308	83	printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
f06d9a2b	84	return -EIO;
1da177e4 LT	85	}
	86	}
	87
	88	static int mtd_blktrans_thread(void *arg)
	89	{
	90	struct mtd_blktrans_ops *tr = arg;
	91	struct request_queue *rq = tr->blkcore_priv->rq;
1498ada7	92	struct request *req = NULL;
1da177e4 LT	93
1da177e4 LT	94	/* we might get involved when memory gets low, so use PF_MEMALLOC */
83144186	95	current->flags \|= PF_MEMALLOC;
1da177e4	96
1da177e4	97	spin_lock_irq(rq->queue_lock);
1498ada7	98
3e67fe45	99	while (!kthread_should_stop()) {
1da177e4	100	struct mtd_blktrans_dev *dev;
f06d9a2b	101	int res;
1da177e4	102
9934c8c0	103	if (!req && !(req = blk_fetch_request(rq))) {
1da177e4	104	set_current_state(TASK_INTERRUPTIBLE);
1da177e4	105	spin_unlock_irq(rq->queue_lock);
1da177e4	106	schedule();
1da177e4	107	spin_lock_irq(rq->queue_lock);
1da177e4 LT	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
1498ada7 TH	122	if (!__blk_end_request_cur(req, res))
1498ada7 TH	123	req = NULL;
1da177e4	124	}
1498ada7 TH	125
	126	if (req)
	127	__blk_end_request_all(req, -EIO);
	128
1da177e4 LT	129	spin_unlock_irq(rq->queue_lock);
1da177e4 LT	130
3e67fe45	131	return 0;
1da177e4 LT	132	}
	133
	134	static void mtd_blktrans_request(struct request_queue *rq)
	135	{
	136	struct mtd_blktrans_ops *tr = rq->queuedata;
3e67fe45	137	wake_up_process(tr->blkcore_priv->thread);
1da177e4 LT	138	}
	139
	140
af0e2a0a	141	static int blktrans_open(struct block_device *bdev, fmode_t mode)
1da177e4	142	{
af0e2a0a AV	143	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
af0e2a0a AV	144	struct mtd_blktrans_ops *tr = dev->tr;
1da177e4 LT	145	int ret = -ENODEV;
1da177e4 LT	146
1da177e4 LT	147	if (!try_module_get(dev->mtd->owner))
	148	goto out;
	149
	150	if (!try_module_get(tr->owner))
	151	goto out_tr;
	152
97894cda	153	/* FIXME: Locking. A hot pluggable device can go away
1da177e4 LT	154	(del_mtd_device can be called for it) without its module
	155	being unloaded. */
	156	dev->mtd->usecount++;
	157
	158	ret = 0;
	159	if (tr->open && (ret = tr->open(dev))) {
	160	dev->mtd->usecount--;
	161	module_put(dev->mtd->owner);
	162	out_tr:
	163	module_put(tr->owner);
	164	}
	165	out:
	166	return ret;
	167	}
	168
af0e2a0a	169	static int blktrans_release(struct gendisk *disk, fmode_t mode)
1da177e4	170	{
af0e2a0a AV	171	struct mtd_blktrans_dev *dev = disk->private_data;
af0e2a0a AV	172	struct mtd_blktrans_ops *tr = dev->tr;
1da177e4 LT	173	int ret = 0;
1da177e4 LT	174
1da177e4 LT	175	if (tr->release)
	176	ret = tr->release(dev);
	177
	178	if (!ret) {
	179	dev->mtd->usecount--;
	180	module_put(dev->mtd->owner);
	181	module_put(tr->owner);
	182	}
	183
	184	return ret;
	185	}
	186
a885c8c4 CH	187	static int blktrans_getgeo(struct block_device bdev, struct hd_geometry geo)
	188	{
	189	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
	190
	191	if (dev->tr->getgeo)
	192	return dev->tr->getgeo(dev, geo);
	193	return -ENOTTY;
	194	}
1da177e4	195
af0e2a0a	196	static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
1da177e4 LT	197	unsigned int cmd, unsigned long arg)
1da177e4 LT	198	{
af0e2a0a	199	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
1da177e4 LT	200	struct mtd_blktrans_ops *tr = dev->tr;
	201
	202	switch (cmd) {
	203	case BLKFLSBUF:
	204	if (tr->flush)
	205	return tr->flush(dev);
	206	/* The core code did the work, we had nothing to do. */
	207	return 0;
1da177e4 LT	208	default:
	209	return -ENOTTY;
	210	}
	211	}
	212
8f026f75	213	static struct block_device_operations mtd_blktrans_ops = {
1da177e4	214	.owner = THIS_MODULE,
af0e2a0a AV	215	.open = blktrans_open,
	216	.release = blktrans_release,
	217	.locked_ioctl = blktrans_ioctl,
a885c8c4	218	.getgeo = blktrans_getgeo,
1da177e4 LT	219	};
	220
	221	int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
	222	{
	223	struct mtd_blktrans_ops *tr = new->tr;
71a928c0	224	struct mtd_blktrans_dev *d;
1da177e4 LT	225	int last_devnum = -1;
	226	struct gendisk *gd;
	227
b3561ea9	228	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	229	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	230	BUG();
	231	}
	232
71a928c0	233	list_for_each_entry(d, &tr->devs, list) {
1da177e4 LT	234	if (new->devnum == -1) {
	235	/* Use first free number */
	236	if (d->devnum != last_devnum+1) {
	237	/* Found a free devnum. Plug it in here */
	238	new->devnum = last_devnum+1;
	239	list_add_tail(&new->list, &d->list);
	240	goto added;
	241	}
	242	} else if (d->devnum == new->devnum) {
	243	/* Required number taken */
	244	return -EBUSY;
	245	} else if (d->devnum > new->devnum) {
	246	/* Required number was free */
	247	list_add_tail(&new->list, &d->list);
	248	goto added;
97894cda	249	}
1da177e4 LT	250	last_devnum = d->devnum;
	251	}
	252	if (new->devnum == -1)
	253	new->devnum = last_devnum+1;
	254
	255	if ((new->devnum << tr->part_bits) > 256) {
	256	return -EBUSY;
	257	}
	258
1da177e4 LT	259	list_add_tail(&new->list, &tr->devs);
1da177e4 LT	260	added:
ce37ab42	261	mutex_init(&new->lock);
1da177e4 LT	262	if (!tr->writesect)
	263	new->readonly = 1;
	264
	265	gd = alloc_disk(1 << tr->part_bits);
	266	if (!gd) {
	267	list_del(&new->list);
	268	return -ENOMEM;
	269	}
	270	gd->major = tr->major;
	271	gd->first_minor = (new->devnum) << tr->part_bits;
	272	gd->fops = &mtd_blktrans_ops;
97894cda	273
65a8de36 TP	274	if (tr->part_bits)
	275	if (new->devnum < 26)
	276	snprintf(gd->disk_name, sizeof(gd->disk_name),
	277	"%s%c", tr->name, 'a' + new->devnum);
	278	else
	279	snprintf(gd->disk_name, sizeof(gd->disk_name),
	280	"%s%c%c", tr->name,
	281	'a' - 1 + new->devnum / 26,
	282	'a' + new->devnum % 26);
	283	else
	284	snprintf(gd->disk_name, sizeof(gd->disk_name),
	285	"%s%d", tr->name, new->devnum);
1da177e4 LT	286
	287	/* 2.5 has capacity in units of 512 bytes while still
	288	having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
19187672	289	set_capacity(gd, (new->size * tr->blksize) >> 9);
1da177e4 LT	290
	291	gd->private_data = new;
	292	new->blkcore_priv = gd;
	293	gd->queue = tr->blkcore_priv->rq;
1f24b5a8	294	gd->driverfs_dev = new->mtd->dev.parent;
1da177e4 LT	295
	296	if (new->readonly)
	297	set_disk_ro(gd, 1);
	298
	299	add_disk(gd);
97894cda	300
1da177e4 LT	301	return 0;
	302	}
	303
	304	int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
	305	{
b3561ea9	306	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	307	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	308	BUG();
	309	}
	310
	311	list_del(&old->list);
	312
	313	del_gendisk(old->blkcore_priv);
	314	put_disk(old->blkcore_priv);
97894cda	315
1da177e4 LT	316	return 0;
	317	}
	318
	319	static void blktrans_notify_remove(struct mtd_info *mtd)
	320	{
71a928c0 CM	321	struct mtd_blktrans_ops *tr;
71a928c0 CM	322	struct mtd_blktrans_dev dev, next;
1da177e4	323
71a928c0 CM	324	list_for_each_entry(tr, &blktrans_majors, list)
71a928c0 CM	325	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4 LT	326	if (dev->mtd == mtd)
1da177e4 LT	327	tr->remove_dev(dev);
1da177e4 LT	328	}
	329
	330	static void blktrans_notify_add(struct mtd_info *mtd)
	331	{
71a928c0	332	struct mtd_blktrans_ops *tr;
1da177e4 LT	333
	334	if (mtd->type == MTD_ABSENT)
	335	return;
	336
71a928c0	337	list_for_each_entry(tr, &blktrans_majors, list)
1da177e4	338	tr->add_mtd(tr, mtd);
1da177e4 LT	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;
e1defc4f	381	blk_queue_logical_block_size(tr->blkcore_priv->rq, tr->blksize);
eae9acd1 DW	382	if (tr->discard)
	383	blk_queue_set_discard(tr->blkcore_priv->rq,
	384	blktrans_discard_request);
	385
19187672	386	tr->blkshift = ffs(tr->blksize) - 1;
1da177e4	387
3e67fe45 CH	388	tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
	389	"%sd", tr->name);
	390	if (IS_ERR(tr->blkcore_priv->thread)) {
2cf3a114	391	int ret = PTR_ERR(tr->blkcore_priv->thread);
1da177e4 LT	392	blk_cleanup_queue(tr->blkcore_priv->rq);
	393	unregister_blkdev(tr->major, tr->name);
	394	kfree(tr->blkcore_priv);
48b19268	395	mutex_unlock(&mtd_table_mutex);
2cf3a114	396	return ret;
97894cda	397	}
1da177e4	398
1da177e4 LT	399	INIT_LIST_HEAD(&tr->devs);
	400	list_add(&tr->list, &blktrans_majors);
	401
	402	for (i=0; i<MAX_MTD_DEVICES; i++) {
	403	if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
	404	tr->add_mtd(tr, mtd_table[i]);
	405	}
	406
48b19268	407	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	408
	409	return 0;
	410	}
	411
	412	int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
	413	{
71a928c0	414	struct mtd_blktrans_dev dev, next;
1da177e4	415
48b19268	416	mutex_lock(&mtd_table_mutex);
1da177e4 LT	417
1da177e4 LT	418	/* Clean up the kernel thread */
3e67fe45	419	kthread_stop(tr->blkcore_priv->thread);
1da177e4 LT	420
	421	/* Remove it from the list of active majors */
	422	list_del(&tr->list);
	423
71a928c0	424	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4	425	tr->remove_dev(dev);
1da177e4	426
1da177e4 LT	427	blk_cleanup_queue(tr->blkcore_priv->rq);
	428	unregister_blkdev(tr->major, tr->name);
	429
48b19268	430	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	431
	432	kfree(tr->blkcore_priv);
	433
373ebfbf	434	BUG_ON(!list_empty(&tr->devs));
1da177e4 LT	435	return 0;
	436	}
	437
	438	static void __exit mtd_blktrans_exit(void)
	439	{
	440	/* No race here -- if someone's currently in register_mtd_blktrans
	441	we're screwed anyway. */
	442	if (blktrans_notifier.list.next)
	443	unregister_mtd_user(&blktrans_notifier);
	444	}
	445
	446	module_exit(mtd_blktrans_exit);
	447
	448	EXPORT_SYMBOL_GPL(register_mtd_blktrans);
	449	EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
	450	EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
	451	EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
	452
	453	MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
	454	MODULE_LICENSE("GPL");
	455	MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");