[GitHub/mt8127/android_kernel_alcatel_ttab.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;
	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;
	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)
		sysfs_create_group(&disk_to_dev(gd)->kobj,
					new->disk_attributes);
	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);
	blk_cleanup_queue(old->rq);

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