[mirror_ubuntu-artful-kernel.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/smp_lock.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 (req->cmd_type != REQ_TYPE_FS)
		return -EIO;

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

	if (req->cmd_flags & REQ_DISCARD)
		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; /* FIXME: busy loop! -arnd*/

	lock_kernel();
	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);
	unlock_kernel();
	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;

	lock_kernel();
	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);
	unlock_kernel();
	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;

	lock_kernel();
	mutex_lock(&dev->lock);

	if (!dev->mtd)
		goto unlock;

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

static const 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 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>
8a6cfeb6	18	#include <linux/smp_lock.h>
1da177e4 LT	19	#include <linux/hdreg.h>
1da177e4 LT	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);
048d8719 ML	28	static DEFINE_MUTEX(blktrans_ref_mutex);
	29
	30	void blktrans_dev_release(struct kref *kref)
	31	{
	32	struct mtd_blktrans_dev *dev =
	33	container_of(kref, struct mtd_blktrans_dev, ref);
	34
	35	dev->disk->private_data = NULL;
e4d64cab	36	blk_cleanup_queue(dev->rq);
048d8719 ML	37	put_disk(dev->disk);
	38	list_del(&dev->list);
	39	kfree(dev);
	40	}
	41
	42	static struct mtd_blktrans_dev blktrans_dev_get(struct gendisk disk)
	43	{
	44	struct mtd_blktrans_dev *dev;
	45
	46	mutex_lock(&blktrans_ref_mutex);
	47	dev = disk->private_data;
	48
	49	if (!dev)
	50	goto unlock;
	51	kref_get(&dev->ref);
	52	unlock:
	53	mutex_unlock(&blktrans_ref_mutex);
	54	return dev;
	55	}
	56
	57	void blktrans_dev_put(struct mtd_blktrans_dev *dev)
	58	{
	59	mutex_lock(&blktrans_ref_mutex);
	60	kref_put(&dev->ref, blktrans_dev_release);
	61	mutex_unlock(&blktrans_ref_mutex);
	62	}
1da177e4	63
1da177e4 LT	64
	65	static int do_blktrans_request(struct mtd_blktrans_ops *tr,
	66	struct mtd_blktrans_dev *dev,
	67	struct request *req)
	68	{
	69	unsigned long block, nsect;
	70	char *buf;
	71
83096ebf	72	block = blk_rq_pos(req) << 9 >> tr->blkshift;
1011c1b9	73	nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
19187672	74
1da177e4 LT	75	buf = req->buffer;
1da177e4 LT	76
33659ebb	77	if (req->cmd_type != REQ_TYPE_FS)
f06d9a2b	78	return -EIO;
1da177e4	79
83096ebf TH	80	if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
83096ebf TH	81	get_capacity(req->rq_disk))
f06d9a2b	82	return -EIO;
1da177e4	83
33659ebb	84	if (req->cmd_flags & REQ_DISCARD)
1122a26f CH	85	return tr->discard(dev, block, nsect);
1122a26f CH	86
1da177e4 LT	87	switch(rq_data_dir(req)) {
1da177e4 LT	88	case READ:
19187672	89	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4	90	if (tr->readsect(dev, block, buf))
f06d9a2b	91	return -EIO;
2d4dc890	92	rq_flush_dcache_pages(req);
f06d9a2b	93	return 0;
1da177e4 LT	94	case WRITE:
1da177e4 LT	95	if (!tr->writesect)
f06d9a2b	96	return -EIO;
1da177e4	97
2d4dc890	98	rq_flush_dcache_pages(req);
19187672	99	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4	100	if (tr->writesect(dev, block, buf))
f06d9a2b TH	101	return -EIO;
f06d9a2b TH	102	return 0;
1da177e4	103	default:
9a292308	104	printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
f06d9a2b	105	return -EIO;
1da177e4 LT	106	}
	107	}
	108
	109	static int mtd_blktrans_thread(void *arg)
	110	{
a8638622 ML	111	struct mtd_blktrans_dev *dev = arg;
a8638622 ML	112	struct request_queue *rq = dev->rq;
1498ada7	113	struct request *req = NULL;
1da177e4	114
1da177e4	115	spin_lock_irq(rq->queue_lock);
1498ada7	116
3e67fe45	117	while (!kthread_should_stop()) {
f06d9a2b	118	int res;
1da177e4	119
9934c8c0	120	if (!req && !(req = blk_fetch_request(rq))) {
1da177e4	121	set_current_state(TASK_INTERRUPTIBLE);
1da177e4	122	spin_unlock_irq(rq->queue_lock);
1da177e4	123	schedule();
1da177e4	124	spin_lock_irq(rq->queue_lock);
1da177e4 LT	125	continue;
	126	}
	127
1da177e4 LT	128	spin_unlock_irq(rq->queue_lock);
1da177e4 LT	129
48b19268	130	mutex_lock(&dev->lock);
a8638622	131	res = do_blktrans_request(dev->tr, dev, req);
48b19268	132	mutex_unlock(&dev->lock);
1da177e4 LT	133
	134	spin_lock_irq(rq->queue_lock);
	135
1498ada7 TH	136	if (!__blk_end_request_cur(req, res))
1498ada7 TH	137	req = NULL;
1da177e4	138	}
1498ada7 TH	139
	140	if (req)
	141	__blk_end_request_all(req, -EIO);
	142
1da177e4 LT	143	spin_unlock_irq(rq->queue_lock);
1da177e4 LT	144
3e67fe45	145	return 0;
1da177e4 LT	146	}
	147
	148	static void mtd_blktrans_request(struct request_queue *rq)
	149	{
048d8719 ML	150	struct mtd_blktrans_dev *dev;
	151	struct request *req = NULL;
	152
	153	dev = rq->queuedata;
1da177e4	154
048d8719 ML	155	if (!dev)
	156	while ((req = blk_fetch_request(rq)) != NULL)
	157	__blk_end_request_all(req, -ENODEV);
	158	else
	159	wake_up_process(dev->thread);
	160	}
1da177e4	161
af0e2a0a	162	static int blktrans_open(struct block_device *bdev, fmode_t mode)
1da177e4	163	{
048d8719 ML	164	struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
	165	int ret;
	166
	167	if (!dev)
6e9624b8	168	return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
048d8719	169
6e9624b8	170	lock_kernel();
048d8719 ML	171	mutex_lock(&dev->lock);
	172
	173	if (!dev->mtd) {
	174	ret = -ENXIO;
	175	goto unlock;
1da177e4	176	}
048d8719 ML	177
	178	ret = !dev->open++ && dev->tr->open ? dev->tr->open(dev) : 0;
	179
	180	/* Take another reference on the device so it won't go away till
	181	last release */
	182	if (!ret)
	183	kref_get(&dev->ref);
	184	unlock:
	185	mutex_unlock(&dev->lock);
	186	blktrans_dev_put(dev);
6e9624b8	187	unlock_kernel();
1da177e4 LT	188	return ret;
	189	}
	190
af0e2a0a	191	static int blktrans_release(struct gendisk *disk, fmode_t mode)
1da177e4	192	{
048d8719 ML	193	struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
048d8719 ML	194	int ret = -ENXIO;
1da177e4	195
048d8719 ML	196	if (!dev)
048d8719 ML	197	return ret;
1da177e4	198
6e9624b8	199	lock_kernel();
048d8719 ML	200	mutex_lock(&dev->lock);
	201
	202	/* Release one reference, we sure its not the last one here*/
	203	kref_put(&dev->ref, blktrans_dev_release);
1da177e4	204
048d8719 ML	205	if (!dev->mtd)
	206	goto unlock;
	207
	208	ret = !--dev->open && dev->tr->release ? dev->tr->release(dev) : 0;
	209	unlock:
	210	mutex_unlock(&dev->lock);
	211	blktrans_dev_put(dev);
6e9624b8	212	unlock_kernel();
1da177e4 LT	213	return ret;
	214	}
	215
a885c8c4 CH	216	static int blktrans_getgeo(struct block_device bdev, struct hd_geometry geo)
a885c8c4 CH	217	{
048d8719 ML	218	struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
	219	int ret = -ENXIO;
	220
	221	if (!dev)
	222	return ret;
	223
	224	mutex_lock(&dev->lock);
a885c8c4	225
048d8719 ML	226	if (!dev->mtd)
	227	goto unlock;
	228
	229	ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
	230	unlock:
	231	mutex_unlock(&dev->lock);
	232	blktrans_dev_put(dev);
	233	return ret;
a885c8c4	234	}
1da177e4	235
af0e2a0a	236	static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
1da177e4 LT	237	unsigned int cmd, unsigned long arg)
1da177e4 LT	238	{
048d8719 ML	239	struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
	240	int ret = -ENXIO;
	241
	242	if (!dev)
	243	return ret;
	244
8a6cfeb6	245	lock_kernel();
048d8719 ML	246	mutex_lock(&dev->lock);
	247
	248	if (!dev->mtd)
	249	goto unlock;
1da177e4 LT	250
	251	switch (cmd) {
	252	case BLKFLSBUF:
048d8719	253	ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
1da177e4	254	default:
048d8719	255	ret = -ENOTTY;
1da177e4	256	}
048d8719 ML	257	unlock:
048d8719 ML	258	mutex_unlock(&dev->lock);
8a6cfeb6	259	unlock_kernel();
048d8719 ML	260	blktrans_dev_put(dev);
048d8719 ML	261	return ret;
1da177e4 LT	262	}
1da177e4 LT	263
83d5cde4	264	static const struct block_device_operations mtd_blktrans_ops = {
1da177e4	265	.owner = THIS_MODULE,
af0e2a0a AV	266	.open = blktrans_open,
af0e2a0a AV	267	.release = blktrans_release,
8a6cfeb6	268	.ioctl = blktrans_ioctl,
a885c8c4	269	.getgeo = blktrans_getgeo,
1da177e4 LT	270	};
	271
	272	int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
	273	{
	274	struct mtd_blktrans_ops *tr = new->tr;
71a928c0	275	struct mtd_blktrans_dev *d;
1da177e4 LT	276	int last_devnum = -1;
1da177e4 LT	277	struct gendisk *gd;
a8638622	278	int ret;
1da177e4	279
b3561ea9	280	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	281	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	282	BUG();
	283	}
	284
048d8719	285	mutex_lock(&blktrans_ref_mutex);
71a928c0	286	list_for_each_entry(d, &tr->devs, list) {
1da177e4 LT	287	if (new->devnum == -1) {
	288	/* Use first free number */
	289	if (d->devnum != last_devnum+1) {
	290	/* Found a free devnum. Plug it in here */
	291	new->devnum = last_devnum+1;
	292	list_add_tail(&new->list, &d->list);
	293	goto added;
	294	}
	295	} else if (d->devnum == new->devnum) {
	296	/* Required number taken */
048d8719	297	mutex_unlock(&blktrans_ref_mutex);
1da177e4 LT	298	return -EBUSY;
	299	} else if (d->devnum > new->devnum) {
	300	/* Required number was free */
	301	list_add_tail(&new->list, &d->list);
	302	goto added;
97894cda	303	}
1da177e4 LT	304	last_devnum = d->devnum;
1da177e4 LT	305	}
a8638622 ML	306
a8638622 ML	307	ret = -EBUSY;
1da177e4 LT	308	if (new->devnum == -1)
	309	new->devnum = last_devnum+1;
	310
4d3a8534 BH	311	/* Check that the device and any partitions will get valid
	312	* minor numbers and that the disk naming code below can cope
	313	* with this number. */
	314	if (new->devnum > (MINORMASK >> tr->part_bits) \|\|
048d8719 ML	315	(tr->part_bits && new->devnum >= 27 * 26)) {
048d8719 ML	316	mutex_unlock(&blktrans_ref_mutex);
a8638622	317	goto error1;
048d8719	318	}
1da177e4	319
1da177e4 LT	320	list_add_tail(&new->list, &tr->devs);
1da177e4 LT	321	added:
048d8719 ML	322	mutex_unlock(&blktrans_ref_mutex);
048d8719 ML	323
ce37ab42	324	mutex_init(&new->lock);
048d8719	325	kref_init(&new->ref);
1da177e4 LT	326	if (!tr->writesect)
	327	new->readonly = 1;
	328
a8638622 ML	329	/* Create gendisk */
a8638622 ML	330	ret = -ENOMEM;
1da177e4	331	gd = alloc_disk(1 << tr->part_bits);
a8638622 ML	332
	333	if (!gd)
	334	goto error2;
	335
	336	new->disk = gd;
	337	gd->private_data = new;
1da177e4 LT	338	gd->major = tr->major;
	339	gd->first_minor = (new->devnum) << tr->part_bits;
	340	gd->fops = &mtd_blktrans_ops;
97894cda	341
65a8de36 TP	342	if (tr->part_bits)
	343	if (new->devnum < 26)
	344	snprintf(gd->disk_name, sizeof(gd->disk_name),
	345	"%s%c", tr->name, 'a' + new->devnum);
	346	else
	347	snprintf(gd->disk_name, sizeof(gd->disk_name),
	348	"%s%c%c", tr->name,
	349	'a' - 1 + new->devnum / 26,
	350	'a' + new->devnum % 26);
	351	else
	352	snprintf(gd->disk_name, sizeof(gd->disk_name),
	353	"%s%d", tr->name, new->devnum);
1da177e4	354
19187672	355	set_capacity(gd, (new->size * tr->blksize) >> 9);
1da177e4	356
a8638622 ML	357	/* Create the request queue */
	358	spin_lock_init(&new->queue_lock);
	359	new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
	360
	361	if (!new->rq)
	362	goto error3;
	363
	364	new->rq->queuedata = new;
	365	blk_queue_logical_block_size(new->rq, tr->blksize);
	366
	367	if (tr->discard)
	368	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
	369	new->rq);
	370
	371	gd->queue = new->rq;
	372
048d8719 ML	373	__get_mtd_device(new->mtd);
	374	__module_get(tr->owner);
	375
a8638622 ML	376	/* Create processing thread */
	377	/* TODO: workqueue ? */
	378	new->thread = kthread_run(mtd_blktrans_thread, new,
	379	"%s%d", tr->name, new->mtd->index);
	380	if (IS_ERR(new->thread)) {
	381	ret = PTR_ERR(new->thread);
	382	goto error4;
	383	}
d694846b	384	gd->driverfs_dev = &new->mtd->dev;
1da177e4 LT	385
	386	if (new->readonly)
	387	set_disk_ro(gd, 1);
	388
	389	add_disk(gd);
026ec578	390
133fa8c7 ML	391	if (new->disk_attributes) {
133fa8c7 ML	392	ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
026ec578	393	new->disk_attributes);
133fa8c7 ML	394	WARN_ON(ret);
133fa8c7 ML	395	}
1da177e4	396	return 0;
a8638622	397	error4:
048d8719 ML	398	module_put(tr->owner);
048d8719 ML	399	__put_mtd_device(new->mtd);
a8638622 ML	400	blk_cleanup_queue(new->rq);
	401	error3:
	402	put_disk(new->disk);
	403	error2:
	404	list_del(&new->list);
	405	error1:
	406	kfree(new);
	407	return ret;
1da177e4 LT	408	}
	409
	410	int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
	411	{
048d8719 ML	412	unsigned long flags;
048d8719 ML	413
b3561ea9	414	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	415	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	416	BUG();
	417	}
	418
048d8719	419	/* Stop new requests to arrive */
a8638622	420	del_gendisk(old->disk);
97894cda	421
026ec578 ML	422	if (old->disk_attributes)
	423	sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
	424	old->disk_attributes);
	425
a8638622 ML	426	/* Stop the thread */
	427	kthread_stop(old->thread);
	428
048d8719 ML	429	/* Kill current requests */
	430	spin_lock_irqsave(&old->queue_lock, flags);
	431	old->rq->queuedata = NULL;
	432	blk_start_queue(old->rq);
	433	spin_unlock_irqrestore(&old->queue_lock, flags);
048d8719 ML	434
	435	/* Ask trans driver for release to the mtd device */
	436	mutex_lock(&old->lock);
	437	if (old->open && old->tr->release) {
	438	old->tr->release(old);
	439	old->open = 0;
	440	}
	441
	442	__put_mtd_device(old->mtd);
	443	module_put(old->tr->owner);
	444
	445	/* At that point, we don't touch the mtd anymore */
	446	old->mtd = NULL;
	447
	448	mutex_unlock(&old->lock);
	449	blktrans_dev_put(old);
1da177e4 LT	450	return 0;
	451	}
	452
	453	static void blktrans_notify_remove(struct mtd_info *mtd)
	454	{
71a928c0 CM	455	struct mtd_blktrans_ops *tr;
71a928c0 CM	456	struct mtd_blktrans_dev dev, next;
1da177e4	457
71a928c0 CM	458	list_for_each_entry(tr, &blktrans_majors, list)
71a928c0 CM	459	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4 LT	460	if (dev->mtd == mtd)
1da177e4 LT	461	tr->remove_dev(dev);
1da177e4 LT	462	}
	463
	464	static void blktrans_notify_add(struct mtd_info *mtd)
	465	{
71a928c0	466	struct mtd_blktrans_ops *tr;
1da177e4 LT	467
	468	if (mtd->type == MTD_ABSENT)
	469	return;
	470
71a928c0	471	list_for_each_entry(tr, &blktrans_majors, list)
1da177e4	472	tr->add_mtd(tr, mtd);
1da177e4 LT	473	}
	474
	475	static struct mtd_notifier blktrans_notifier = {
	476	.add = blktrans_notify_add,
	477	.remove = blktrans_notify_remove,
	478	};
97894cda	479
1da177e4 LT	480	int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
1da177e4 LT	481	{
f1332ba2 BH	482	struct mtd_info *mtd;
f1332ba2 BH	483	int ret;
1da177e4	484
97894cda	485	/* Register the notifier if/when the first device type is
1da177e4 LT	486	registered, to prevent the link/init ordering from fucking
	487	us over. */
	488	if (!blktrans_notifier.list.next)
	489	register_mtd_user(&blktrans_notifier);
	490
1da177e4	491
48b19268	492	mutex_lock(&mtd_table_mutex);
1da177e4 LT	493
	494	ret = register_blkdev(tr->major, tr->name);
	495	if (ret) {
	496	printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
	497	tr->name, tr->major, ret);
48b19268	498	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	499	return ret;
1da177e4 LT	500	}
eae9acd1	501
19187672	502	tr->blkshift = ffs(tr->blksize) - 1;
1da177e4	503
1da177e4 LT	504	INIT_LIST_HEAD(&tr->devs);
	505	list_add(&tr->list, &blktrans_majors);
	506
f1332ba2 BH	507	mtd_for_each_device(mtd)
	508	if (mtd->type != MTD_ABSENT)
	509	tr->add_mtd(tr, mtd);
1da177e4	510
48b19268	511	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	512	return 0;
	513	}
	514
	515	int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
	516	{
71a928c0	517	struct mtd_blktrans_dev dev, next;
1da177e4	518
48b19268	519	mutex_lock(&mtd_table_mutex);
1da177e4	520
1da177e4 LT	521	/* Remove it from the list of active majors */
	522	list_del(&tr->list);
	523
71a928c0	524	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4	525	tr->remove_dev(dev);
1da177e4	526
1da177e4	527	unregister_blkdev(tr->major, tr->name);
48b19268	528	mutex_unlock(&mtd_table_mutex);
1da177e4	529
373ebfbf	530	BUG_ON(!list_empty(&tr->devs));
1da177e4 LT	531	return 0;
	532	}
	533
	534	static void __exit mtd_blktrans_exit(void)
	535	{
	536	/* No race here -- if someone's currently in register_mtd_blktrans
	537	we're screwed anyway. */
	538	if (blktrans_notifier.list.next)
	539	unregister_mtd_user(&blktrans_notifier);
	540	}
	541
	542	module_exit(mtd_blktrans_exit);
	543
	544	EXPORT_SYMBOL_GPL(register_mtd_blktrans);
	545	EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
	546	EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
	547	EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
	548
	549	MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
	550	MODULE_LICENSE("GPL");
	551	MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");