[linux-2.6-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/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);
static DEFINE_MUTEX(blktrans_ref_mutex);

void blktrans_dev_release(struct kref *kref)
{
	struct mtd_blktrans_dev *dev =
		container_of(kref, struct mtd_blktrans_dev, ref);

	dev->disk->private_data = NULL;
	blk_cleanup_queue(dev->rq);
	put_disk(dev->disk);
	list_del(&dev->list);
	kfree(dev);
}

static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
{
	struct mtd_blktrans_dev *dev;

	mutex_lock(&blktrans_ref_mutex);
	dev = disk->private_data;

	if (!dev)
		goto unlock;
	kref_get(&dev->ref);
unlock:
	mutex_unlock(&blktrans_ref_mutex);
	return dev;
}

void blktrans_dev_put(struct mtd_blktrans_dev *dev)
{
	mutex_lock(&blktrans_ref_mutex);
	kref_put(&dev->ref, blktrans_dev_release);
	mutex_unlock(&blktrans_ref_mutex);
}


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

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

	buf = req->buffer;

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

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

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

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

		rq_flush_dcache_pages(req);
		for (; nsect > 0; nsect--, block++, buf += tr->blksize)
			if (tr->writesect(dev, block, buf))
				return -EIO;
		return 0;
	default:
		printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
		return -EIO;
	}
}

static int mtd_blktrans_thread(void *arg)
{
	struct mtd_blktrans_dev *dev = arg;
	struct request_queue *rq = dev->rq;
	struct request *req = NULL;

	spin_lock_irq(rq->queue_lock);

	while (!kthread_should_stop()) {
		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;
		}

		spin_unlock_irq(rq->queue_lock);

		mutex_lock(&dev->lock);
		res = do_blktrans_request(dev->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_dev *dev;
	struct request *req = NULL;

	dev = rq->queuedata;

	if (!dev)
		while ((req = blk_fetch_request(rq)) != NULL)
			__blk_end_request_all(req, -ENODEV);
	else
		wake_up_process(dev->thread);
}

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

	if (!dev)
		return -ERESTARTSYS;

	mutex_lock(&dev->lock);

	if (!dev->mtd) {
		ret = -ENXIO;
		goto unlock;
	}

	ret = !dev->open++ && dev->tr->open ? dev->tr->open(dev) : 0;

	/* Take another reference on the device so it won't go away till
		last release */
	if (!ret)
		kref_get(&dev->ref);
unlock:
	mutex_unlock(&dev->lock);
	blktrans_dev_put(dev);
	return ret;
}

static int blktrans_release(struct gendisk *disk, fmode_t mode)
{
	struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
	int ret = -ENXIO;

	if (!dev)
		return ret;

	mutex_lock(&dev->lock);

	/* Release one reference, we sure its not the last one here*/
	kref_put(&dev->ref, blktrans_dev_release);

	if (!dev->mtd)
		goto unlock;

	ret = !--dev->open && dev->tr->release ? dev->tr->release(dev) : 0;
unlock:
	mutex_unlock(&dev->lock);
	blktrans_dev_put(dev);
	return ret;
}

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

	if (!dev)
		return ret;

	mutex_lock(&dev->lock);

	if (!dev->mtd)
		goto unlock;

	ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
unlock:
	mutex_unlock(&dev->lock);
	blktrans_dev_put(dev);
	return ret;
}

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

	if (!dev)
		return ret;

	mutex_lock(&dev->lock);

	if (!dev->mtd)
		goto unlock;

	switch (cmd) {
	case BLKFLSBUF:
		ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
		break;
	default:
		ret = -ENOTTY;
	}
unlock:
	mutex_unlock(&dev->lock);
	blktrans_dev_put(dev);
	return ret;
}

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

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

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

	mutex_lock(&blktrans_ref_mutex);
	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 */
			mutex_unlock(&blktrans_ref_mutex);
			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;
	}

	ret = -EBUSY;
	if (new->devnum == -1)
		new->devnum = last_devnum+1;

	/* Check that the device and any partitions will get valid
	 * minor numbers and that the disk naming code below can cope
	 * with this number. */
	if (new->devnum > (MINORMASK >> tr->part_bits) ||
	    (tr->part_bits && new->devnum >= 27 * 26)) {
		mutex_unlock(&blktrans_ref_mutex);
		goto error1;
	}

	list_add_tail(&new->list, &tr->devs);
 added:
	mutex_unlock(&blktrans_ref_mutex);

	mutex_init(&new->lock);
	kref_init(&new->ref);
	if (!tr->writesect)
		new->readonly = 1;

	/* Create gendisk */
	ret = -ENOMEM;
	gd = alloc_disk(1 << tr->part_bits);

	if (!gd)
		goto error2;

	new->disk = gd;
	gd->private_data = new;
	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);

	set_capacity(gd, (new->size * tr->blksize) >> 9);

	/* Create the request queue */
	spin_lock_init(&new->queue_lock);
	new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);

	if (!new->rq)
		goto error3;

	new->rq->queuedata = new;
	blk_queue_logical_block_size(new->rq, tr->blksize);

	if (tr->discard)
		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
					new->rq);

	gd->queue = new->rq;

	__get_mtd_device(new->mtd);
	__module_get(tr->owner);

	/* Create processing thread */
	/* TODO: workqueue ? */
	new->thread = kthread_run(mtd_blktrans_thread, new,
			"%s%d", tr->name, new->mtd->index);
	if (IS_ERR(new->thread)) {
		ret = PTR_ERR(new->thread);
		goto error4;
	}
	gd->driverfs_dev = &new->mtd->dev;

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

	add_disk(gd);

	if (new->disk_attributes) {
		ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
					new->disk_attributes);
		WARN_ON(ret);
	}
	return 0;
error4:
	module_put(tr->owner);
	__put_mtd_device(new->mtd);
	blk_cleanup_queue(new->rq);
error3:
	put_disk(new->disk);
error2:
	list_del(&new->list);
error1:
	kfree(new);
	return ret;
}

int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
{
	unsigned long flags;

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

	/* Stop new requests to arrive */
	del_gendisk(old->disk);

	if (old->disk_attributes)
		sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
						old->disk_attributes);

	/* Stop the thread */
	kthread_stop(old->thread);

	/* Kill current requests */
	spin_lock_irqsave(&old->queue_lock, flags);
	old->rq->queuedata = NULL;
	blk_start_queue(old->rq);
	spin_unlock_irqrestore(&old->queue_lock, flags);

	/* Ask trans driver for release to the mtd device */
	mutex_lock(&old->lock);
	if (old->open && old->tr->release) {
		old->tr->release(old);
		old->open = 0;
	}

	__put_mtd_device(old->mtd);
	module_put(old->tr->owner);

	/* At that point, we don't touch the mtd anymore */
	old->mtd = NULL;

	mutex_unlock(&old->lock);
	blktrans_dev_put(old);
	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)
{
	struct mtd_info *mtd;
	int ret;

	/* 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);


	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);
		mutex_unlock(&mtd_table_mutex);
		return ret;
	}

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

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

	mtd_for_each_device(mtd)
		if (mtd->type != MTD_ABSENT)
			tr->add_mtd(tr, mtd);

	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);

	/* 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);

	unregister_blkdev(tr->major, tr->name);
	mutex_unlock(&mtd_table_mutex);

	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>
	17	#include <linux/spinlock.h>
	18	#include <linux/hdreg.h>
	19	#include <linux/init.h>
48b19268	20	#include <linux/mutex.h>
99f9b243	21	#include <linux/kthread.h>
1da177e4	22	#include <asm/uaccess.h>
1da177e4	23
356d70f1	24	#include "mtdcore.h"
1da177e4	25
356d70f1	26	static LIST_HEAD(blktrans_majors);
048d8719 ML	27	static DEFINE_MUTEX(blktrans_ref_mutex);
	28
	29	void blktrans_dev_release(struct kref *kref)
	30	{
	31	struct mtd_blktrans_dev *dev =
	32	container_of(kref, struct mtd_blktrans_dev, ref);
	33
	34	dev->disk->private_data = NULL;
e4d64cab	35	blk_cleanup_queue(dev->rq);
048d8719 ML	36	put_disk(dev->disk);
	37	list_del(&dev->list);
	38	kfree(dev);
	39	}
	40
	41	static struct mtd_blktrans_dev blktrans_dev_get(struct gendisk disk)
	42	{
	43	struct mtd_blktrans_dev *dev;
	44
	45	mutex_lock(&blktrans_ref_mutex);
	46	dev = disk->private_data;
	47
	48	if (!dev)
	49	goto unlock;
	50	kref_get(&dev->ref);
	51	unlock:
	52	mutex_unlock(&blktrans_ref_mutex);
	53	return dev;
	54	}
	55
	56	void blktrans_dev_put(struct mtd_blktrans_dev *dev)
	57	{
	58	mutex_lock(&blktrans_ref_mutex);
	59	kref_put(&dev->ref, blktrans_dev_release);
	60	mutex_unlock(&blktrans_ref_mutex);
	61	}
1da177e4	62
1da177e4 LT	63
	64	static int do_blktrans_request(struct mtd_blktrans_ops *tr,
	65	struct mtd_blktrans_dev *dev,
	66	struct request *req)
	67	{
	68	unsigned long block, nsect;
	69	char *buf;
	70
83096ebf	71	block = blk_rq_pos(req) << 9 >> tr->blkshift;
1011c1b9	72	nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
19187672	73
1da177e4 LT	74	buf = req->buffer;
1da177e4 LT	75
4aff5e23	76	if (!blk_fs_request(req))
f06d9a2b	77	return -EIO;
1da177e4	78
83096ebf TH	79	if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
83096ebf TH	80	get_capacity(req->rq_disk))
f06d9a2b	81	return -EIO;
1da177e4	82
1122a26f CH	83	if (blk_discard_rq(req))
	84	return tr->discard(dev, block, nsect);
	85
1da177e4 LT	86	switch(rq_data_dir(req)) {
1da177e4 LT	87	case READ:
19187672	88	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4	89	if (tr->readsect(dev, block, buf))
f06d9a2b	90	return -EIO;
2d4dc890	91	rq_flush_dcache_pages(req);
f06d9a2b	92	return 0;
1da177e4 LT	93	case WRITE:
1da177e4 LT	94	if (!tr->writesect)
f06d9a2b	95	return -EIO;
1da177e4	96
2d4dc890	97	rq_flush_dcache_pages(req);
19187672	98	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4	99	if (tr->writesect(dev, block, buf))
f06d9a2b TH	100	return -EIO;
f06d9a2b TH	101	return 0;
1da177e4	102	default:
9a292308	103	printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
f06d9a2b	104	return -EIO;
1da177e4 LT	105	}
	106	}
	107
	108	static int mtd_blktrans_thread(void *arg)
	109	{
a8638622 ML	110	struct mtd_blktrans_dev *dev = arg;
a8638622 ML	111	struct request_queue *rq = dev->rq;
1498ada7	112	struct request *req = NULL;
1da177e4	113
1da177e4	114	spin_lock_irq(rq->queue_lock);
1498ada7	115
3e67fe45	116	while (!kthread_should_stop()) {
f06d9a2b	117	int res;
1da177e4	118
9934c8c0	119	if (!req && !(req = blk_fetch_request(rq))) {
1da177e4	120	set_current_state(TASK_INTERRUPTIBLE);
1da177e4	121	spin_unlock_irq(rq->queue_lock);
1da177e4	122	schedule();
1da177e4	123	spin_lock_irq(rq->queue_lock);
1da177e4 LT	124	continue;
	125	}
	126
1da177e4 LT	127	spin_unlock_irq(rq->queue_lock);
1da177e4 LT	128
48b19268	129	mutex_lock(&dev->lock);
a8638622	130	res = do_blktrans_request(dev->tr, dev, req);
48b19268	131	mutex_unlock(&dev->lock);
1da177e4 LT	132
	133	spin_lock_irq(rq->queue_lock);
	134
1498ada7 TH	135	if (!__blk_end_request_cur(req, res))
1498ada7 TH	136	req = NULL;
1da177e4	137	}
1498ada7 TH	138
	139	if (req)
	140	__blk_end_request_all(req, -EIO);
	141
1da177e4 LT	142	spin_unlock_irq(rq->queue_lock);
1da177e4 LT	143
3e67fe45	144	return 0;
1da177e4 LT	145	}
	146
	147	static void mtd_blktrans_request(struct request_queue *rq)
	148	{
048d8719 ML	149	struct mtd_blktrans_dev *dev;
	150	struct request *req = NULL;
	151
	152	dev = rq->queuedata;
1da177e4	153
048d8719 ML	154	if (!dev)
	155	while ((req = blk_fetch_request(rq)) != NULL)
	156	__blk_end_request_all(req, -ENODEV);
	157	else
	158	wake_up_process(dev->thread);
	159	}
1da177e4	160
af0e2a0a	161	static int blktrans_open(struct block_device *bdev, fmode_t mode)
1da177e4	162	{
048d8719 ML	163	struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
	164	int ret;
	165
	166	if (!dev)
	167	return -ERESTARTSYS;
	168
	169	mutex_lock(&dev->lock);
	170
	171	if (!dev->mtd) {
	172	ret = -ENXIO;
	173	goto unlock;
1da177e4	174	}
048d8719 ML	175
	176	ret = !dev->open++ && dev->tr->open ? dev->tr->open(dev) : 0;
	177
	178	/* Take another reference on the device so it won't go away till
	179	last release */
	180	if (!ret)
	181	kref_get(&dev->ref);
	182	unlock:
	183	mutex_unlock(&dev->lock);
	184	blktrans_dev_put(dev);
1da177e4 LT	185	return ret;
	186	}
	187
af0e2a0a	188	static int blktrans_release(struct gendisk *disk, fmode_t mode)
1da177e4	189	{
048d8719 ML	190	struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
048d8719 ML	191	int ret = -ENXIO;
1da177e4	192
048d8719 ML	193	if (!dev)
048d8719 ML	194	return ret;
1da177e4	195
048d8719 ML	196	mutex_lock(&dev->lock);
	197
	198	/* Release one reference, we sure its not the last one here*/
	199	kref_put(&dev->ref, blktrans_dev_release);
1da177e4	200
048d8719 ML	201	if (!dev->mtd)
	202	goto unlock;
	203
	204	ret = !--dev->open && dev->tr->release ? dev->tr->release(dev) : 0;
	205	unlock:
	206	mutex_unlock(&dev->lock);
	207	blktrans_dev_put(dev);
1da177e4 LT	208	return ret;
	209	}
	210
a885c8c4 CH	211	static int blktrans_getgeo(struct block_device bdev, struct hd_geometry geo)
a885c8c4 CH	212	{
048d8719 ML	213	struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
	214	int ret = -ENXIO;
	215
	216	if (!dev)
	217	return ret;
	218
	219	mutex_lock(&dev->lock);
a885c8c4	220
048d8719 ML	221	if (!dev->mtd)
	222	goto unlock;
	223
	224	ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
	225	unlock:
	226	mutex_unlock(&dev->lock);
	227	blktrans_dev_put(dev);
	228	return ret;
a885c8c4	229	}
1da177e4	230
af0e2a0a	231	static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
1da177e4 LT	232	unsigned int cmd, unsigned long arg)
1da177e4 LT	233	{
048d8719 ML	234	struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
	235	int ret = -ENXIO;
	236
	237	if (!dev)
	238	return ret;
	239
	240	mutex_lock(&dev->lock);
	241
	242	if (!dev->mtd)
	243	goto unlock;
1da177e4 LT	244
	245	switch (cmd) {
	246	case BLKFLSBUF:
048d8719	247	ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
007c2d87	248	break;
1da177e4	249	default:
048d8719	250	ret = -ENOTTY;
1da177e4	251	}
048d8719 ML	252	unlock:
	253	mutex_unlock(&dev->lock);
	254	blktrans_dev_put(dev);
	255	return ret;
1da177e4 LT	256	}
1da177e4 LT	257
83d5cde4	258	static const struct block_device_operations mtd_blktrans_ops = {
1da177e4	259	.owner = THIS_MODULE,
af0e2a0a AV	260	.open = blktrans_open,
	261	.release = blktrans_release,
	262	.locked_ioctl = blktrans_ioctl,
a885c8c4	263	.getgeo = blktrans_getgeo,
1da177e4 LT	264	};
	265
	266	int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
	267	{
	268	struct mtd_blktrans_ops *tr = new->tr;
71a928c0	269	struct mtd_blktrans_dev *d;
1da177e4 LT	270	int last_devnum = -1;
1da177e4 LT	271	struct gendisk *gd;
a8638622	272	int ret;
1da177e4	273
b3561ea9	274	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	275	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	276	BUG();
	277	}
	278
048d8719	279	mutex_lock(&blktrans_ref_mutex);
71a928c0	280	list_for_each_entry(d, &tr->devs, list) {
1da177e4 LT	281	if (new->devnum == -1) {
	282	/* Use first free number */
	283	if (d->devnum != last_devnum+1) {
	284	/* Found a free devnum. Plug it in here */
	285	new->devnum = last_devnum+1;
	286	list_add_tail(&new->list, &d->list);
	287	goto added;
	288	}
	289	} else if (d->devnum == new->devnum) {
	290	/* Required number taken */
048d8719	291	mutex_unlock(&blktrans_ref_mutex);
1da177e4 LT	292	return -EBUSY;
	293	} else if (d->devnum > new->devnum) {
	294	/* Required number was free */
	295	list_add_tail(&new->list, &d->list);
	296	goto added;
97894cda	297	}
1da177e4 LT	298	last_devnum = d->devnum;
1da177e4 LT	299	}
a8638622 ML	300
a8638622 ML	301	ret = -EBUSY;
1da177e4 LT	302	if (new->devnum == -1)
	303	new->devnum = last_devnum+1;
	304
4d3a8534 BH	305	/* Check that the device and any partitions will get valid
	306	* minor numbers and that the disk naming code below can cope
	307	* with this number. */
	308	if (new->devnum > (MINORMASK >> tr->part_bits) \|\|
048d8719 ML	309	(tr->part_bits && new->devnum >= 27 * 26)) {
048d8719 ML	310	mutex_unlock(&blktrans_ref_mutex);
a8638622	311	goto error1;
048d8719	312	}
1da177e4	313
1da177e4 LT	314	list_add_tail(&new->list, &tr->devs);
1da177e4 LT	315	added:
048d8719 ML	316	mutex_unlock(&blktrans_ref_mutex);
048d8719 ML	317
ce37ab42	318	mutex_init(&new->lock);
048d8719	319	kref_init(&new->ref);
1da177e4 LT	320	if (!tr->writesect)
	321	new->readonly = 1;
	322
a8638622 ML	323	/* Create gendisk */
a8638622 ML	324	ret = -ENOMEM;
1da177e4	325	gd = alloc_disk(1 << tr->part_bits);
a8638622 ML	326
	327	if (!gd)
	328	goto error2;
	329
	330	new->disk = gd;
	331	gd->private_data = new;
1da177e4 LT	332	gd->major = tr->major;
	333	gd->first_minor = (new->devnum) << tr->part_bits;
	334	gd->fops = &mtd_blktrans_ops;
97894cda	335
65a8de36 TP	336	if (tr->part_bits)
	337	if (new->devnum < 26)
	338	snprintf(gd->disk_name, sizeof(gd->disk_name),
	339	"%s%c", tr->name, 'a' + new->devnum);
	340	else
	341	snprintf(gd->disk_name, sizeof(gd->disk_name),
	342	"%s%c%c", tr->name,
	343	'a' - 1 + new->devnum / 26,
	344	'a' + new->devnum % 26);
	345	else
	346	snprintf(gd->disk_name, sizeof(gd->disk_name),
	347	"%s%d", tr->name, new->devnum);
1da177e4	348
19187672	349	set_capacity(gd, (new->size * tr->blksize) >> 9);
1da177e4	350
a8638622 ML	351	/* Create the request queue */
	352	spin_lock_init(&new->queue_lock);
	353	new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
	354
	355	if (!new->rq)
	356	goto error3;
	357
	358	new->rq->queuedata = new;
	359	blk_queue_logical_block_size(new->rq, tr->blksize);
	360
	361	if (tr->discard)
	362	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
	363	new->rq);
	364
	365	gd->queue = new->rq;
	366
048d8719 ML	367	__get_mtd_device(new->mtd);
	368	__module_get(tr->owner);
	369
a8638622 ML	370	/* Create processing thread */
	371	/* TODO: workqueue ? */
	372	new->thread = kthread_run(mtd_blktrans_thread, new,
	373	"%s%d", tr->name, new->mtd->index);
	374	if (IS_ERR(new->thread)) {
	375	ret = PTR_ERR(new->thread);
	376	goto error4;
	377	}
d694846b	378	gd->driverfs_dev = &new->mtd->dev;
1da177e4 LT	379
	380	if (new->readonly)
	381	set_disk_ro(gd, 1);
	382
	383	add_disk(gd);
026ec578	384
133fa8c7 ML	385	if (new->disk_attributes) {
133fa8c7 ML	386	ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
026ec578	387	new->disk_attributes);
133fa8c7 ML	388	WARN_ON(ret);
133fa8c7 ML	389	}
1da177e4	390	return 0;
a8638622	391	error4:
048d8719 ML	392	module_put(tr->owner);
048d8719 ML	393	__put_mtd_device(new->mtd);
a8638622 ML	394	blk_cleanup_queue(new->rq);
	395	error3:
	396	put_disk(new->disk);
	397	error2:
	398	list_del(&new->list);
	399	error1:
	400	kfree(new);
	401	return ret;
1da177e4 LT	402	}
	403
	404	int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
	405	{
048d8719 ML	406	unsigned long flags;
048d8719 ML	407
b3561ea9	408	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	409	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	410	BUG();
	411	}
	412
048d8719	413	/* Stop new requests to arrive */
a8638622	414	del_gendisk(old->disk);
97894cda	415
026ec578 ML	416	if (old->disk_attributes)
	417	sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
	418	old->disk_attributes);
	419
a8638622 ML	420	/* Stop the thread */
	421	kthread_stop(old->thread);
	422
048d8719 ML	423	/* Kill current requests */
	424	spin_lock_irqsave(&old->queue_lock, flags);
	425	old->rq->queuedata = NULL;
	426	blk_start_queue(old->rq);
	427	spin_unlock_irqrestore(&old->queue_lock, flags);
048d8719 ML	428
	429	/* Ask trans driver for release to the mtd device */
	430	mutex_lock(&old->lock);
	431	if (old->open && old->tr->release) {
	432	old->tr->release(old);
	433	old->open = 0;
	434	}
	435
	436	__put_mtd_device(old->mtd);
	437	module_put(old->tr->owner);
	438
	439	/* At that point, we don't touch the mtd anymore */
	440	old->mtd = NULL;
	441
	442	mutex_unlock(&old->lock);
	443	blktrans_dev_put(old);
1da177e4 LT	444	return 0;
	445	}
	446
	447	static void blktrans_notify_remove(struct mtd_info *mtd)
	448	{
71a928c0 CM	449	struct mtd_blktrans_ops *tr;
71a928c0 CM	450	struct mtd_blktrans_dev dev, next;
1da177e4	451
71a928c0 CM	452	list_for_each_entry(tr, &blktrans_majors, list)
71a928c0 CM	453	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4 LT	454	if (dev->mtd == mtd)
1da177e4 LT	455	tr->remove_dev(dev);
1da177e4 LT	456	}
	457
	458	static void blktrans_notify_add(struct mtd_info *mtd)
	459	{
71a928c0	460	struct mtd_blktrans_ops *tr;
1da177e4 LT	461
	462	if (mtd->type == MTD_ABSENT)
	463	return;
	464
71a928c0	465	list_for_each_entry(tr, &blktrans_majors, list)
1da177e4	466	tr->add_mtd(tr, mtd);
1da177e4 LT	467	}
	468
	469	static struct mtd_notifier blktrans_notifier = {
	470	.add = blktrans_notify_add,
	471	.remove = blktrans_notify_remove,
	472	};
97894cda	473
1da177e4 LT	474	int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
1da177e4 LT	475	{
f1332ba2 BH	476	struct mtd_info *mtd;
f1332ba2 BH	477	int ret;
1da177e4	478
97894cda	479	/* Register the notifier if/when the first device type is
1da177e4 LT	480	registered, to prevent the link/init ordering from fucking
	481	us over. */
	482	if (!blktrans_notifier.list.next)
	483	register_mtd_user(&blktrans_notifier);
	484
1da177e4	485
48b19268	486	mutex_lock(&mtd_table_mutex);
1da177e4 LT	487
	488	ret = register_blkdev(tr->major, tr->name);
	489	if (ret) {
	490	printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
	491	tr->name, tr->major, ret);
48b19268	492	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	493	return ret;
1da177e4 LT	494	}
eae9acd1	495
19187672	496	tr->blkshift = ffs(tr->blksize) - 1;
1da177e4	497
1da177e4 LT	498	INIT_LIST_HEAD(&tr->devs);
	499	list_add(&tr->list, &blktrans_majors);
	500
f1332ba2 BH	501	mtd_for_each_device(mtd)
	502	if (mtd->type != MTD_ABSENT)
	503	tr->add_mtd(tr, mtd);
1da177e4	504
48b19268	505	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	506	return 0;
	507	}
	508
	509	int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
	510	{
71a928c0	511	struct mtd_blktrans_dev dev, next;
1da177e4	512
48b19268	513	mutex_lock(&mtd_table_mutex);
1da177e4	514
1da177e4 LT	515	/* Remove it from the list of active majors */
	516	list_del(&tr->list);
	517
71a928c0	518	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4	519	tr->remove_dev(dev);
1da177e4	520
1da177e4	521	unregister_blkdev(tr->major, tr->name);
48b19268	522	mutex_unlock(&mtd_table_mutex);
1da177e4	523
373ebfbf	524	BUG_ON(!list_empty(&tr->devs));
1da177e4 LT	525	return 0;
	526	}
	527
	528	static void __exit mtd_blktrans_exit(void)
	529	{
	530	/* No race here -- if someone's currently in register_mtd_blktrans
	531	we're screwed anyway. */
	532	if (blktrans_notifier.list.next)
	533	unregister_mtd_user(&blktrans_notifier);
	534	}
	535
	536	module_exit(mtd_blktrans_exit);
	537
	538	EXPORT_SYMBOL_GPL(register_mtd_blktrans);
	539	EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
	540	EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
	541	EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
	542
	543	MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
	544	MODULE_LICENSE("GPL");
	545	MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");