[linux-2.6-block.git] / drivers / mtd / mtd_blkdevs.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Interface to Linux block layer for MTD 'translation layers'.
 *
 * Copyright © 2003-2010 David Woodhouse <dwmw2@infradead.org>
 */

#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/blk-mq.h>
#include <linux/blkpg.h>
#include <linux/spinlock.h>
#include <linux/hdreg.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>

#include "mtdcore.h"

static LIST_HEAD(blktrans_majors);

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

	put_disk(dev->disk);
	blk_mq_free_tag_set(dev->tag_set);
	kfree(dev->tag_set);
	list_del(&dev->list);
	kfree(dev);
}

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


static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr,
			       struct mtd_blktrans_dev *dev,
			       struct request *req)
{
	struct req_iterator iter;
	struct bio_vec bvec;
	unsigned long block, nsect;
	char *buf;

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

	switch (req_op(req)) {
	case REQ_OP_FLUSH:
		if (tr->flush(dev))
			return BLK_STS_IOERR;
		return BLK_STS_OK;
	case REQ_OP_DISCARD:
		if (tr->discard(dev, block, nsect))
			return BLK_STS_IOERR;
		return BLK_STS_OK;
	case REQ_OP_READ:
		buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
		for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
			if (tr->readsect(dev, block, buf)) {
				kunmap(bio_page(req->bio));
				return BLK_STS_IOERR;
			}
		}
		kunmap(bio_page(req->bio));

		rq_for_each_segment(bvec, req, iter)
			flush_dcache_page(bvec.bv_page);
		return BLK_STS_OK;
	case REQ_OP_WRITE:
		if (!tr->writesect)
			return BLK_STS_IOERR;

		rq_for_each_segment(bvec, req, iter)
			flush_dcache_page(bvec.bv_page);

		buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
		for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
			if (tr->writesect(dev, block, buf)) {
				kunmap(bio_page(req->bio));
				return BLK_STS_IOERR;
			}
		}
		kunmap(bio_page(req->bio));
		return BLK_STS_OK;
	default:
		return BLK_STS_IOERR;
	}
}

int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
{
	return dev->bg_stop;
}
EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);

static struct request *mtd_next_request(struct mtd_blktrans_dev *dev)
{
	struct request *rq;

	rq = list_first_entry_or_null(&dev->rq_list, struct request, queuelist);
	if (rq) {
		list_del_init(&rq->queuelist);
		blk_mq_start_request(rq);
		return rq;
	}

	return NULL;
}

static void mtd_blktrans_work(struct mtd_blktrans_dev *dev)
	__releases(&dev->queue_lock)
	__acquires(&dev->queue_lock)
{
	struct mtd_blktrans_ops *tr = dev->tr;
	struct request *req = NULL;
	int background_done = 0;

	while (1) {
		blk_status_t res;

		dev->bg_stop = false;
		if (!req && !(req = mtd_next_request(dev))) {
			if (tr->background && !background_done) {
				spin_unlock_irq(&dev->queue_lock);
				mutex_lock(&dev->lock);
				tr->background(dev);
				mutex_unlock(&dev->lock);
				spin_lock_irq(&dev->queue_lock);
				/*
				 * Do background processing just once per idle
				 * period.
				 */
				background_done = !dev->bg_stop;
				continue;
			}
			break;
		}

		spin_unlock_irq(&dev->queue_lock);

		mutex_lock(&dev->lock);
		res = do_blktrans_request(dev->tr, dev, req);
		mutex_unlock(&dev->lock);

		if (!blk_update_request(req, res, blk_rq_cur_bytes(req))) {
			__blk_mq_end_request(req, res);
			req = NULL;
		}

		background_done = 0;
		cond_resched();
		spin_lock_irq(&dev->queue_lock);
	}
}

static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx,
				 const struct blk_mq_queue_data *bd)
{
	struct mtd_blktrans_dev *dev;

	dev = hctx->queue->queuedata;
	if (!dev) {
		blk_mq_start_request(bd->rq);
		return BLK_STS_IOERR;
	}

	spin_lock_irq(&dev->queue_lock);
	list_add_tail(&bd->rq->queuelist, &dev->rq_list);
	mtd_blktrans_work(dev);
	spin_unlock_irq(&dev->queue_lock);

	return BLK_STS_OK;
}

static int blktrans_open(struct gendisk *disk, blk_mode_t mode)
{
	struct mtd_blktrans_dev *dev = disk->private_data;
	int ret = 0;

	kref_get(&dev->ref);

	mutex_lock(&dev->lock);

	if (dev->open)
		goto unlock;

	__module_get(dev->tr->owner);

	if (!dev->mtd)
		goto unlock;

	if (dev->tr->open) {
		ret = dev->tr->open(dev);
		if (ret)
			goto error_put;
	}

	ret = __get_mtd_device(dev->mtd);
	if (ret)
		goto error_release;
	dev->writable = mode & BLK_OPEN_WRITE;

unlock:
	dev->open++;
	mutex_unlock(&dev->lock);
	return ret;

error_release:
	if (dev->tr->release)
		dev->tr->release(dev);
error_put:
	module_put(dev->tr->owner);
	mutex_unlock(&dev->lock);
	blktrans_dev_put(dev);
	return ret;
}

static void blktrans_release(struct gendisk *disk)
{
	struct mtd_blktrans_dev *dev = disk->private_data;

	mutex_lock(&dev->lock);

	if (--dev->open)
		goto unlock;

	module_put(dev->tr->owner);

	if (dev->mtd) {
		if (dev->tr->release)
			dev->tr->release(dev);
		__put_mtd_device(dev->mtd);
	}
unlock:
	mutex_unlock(&dev->lock);
	blktrans_dev_put(dev);
}

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

	mutex_lock(&dev->lock);

	if (!dev->mtd)
		goto unlock;

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

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

static const struct blk_mq_ops mtd_mq_ops = {
	.queue_rq	= mtd_queue_rq,
};

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

	lockdep_assert_held(&mtd_table_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 */
			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))
		return ret;

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

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

	ret = -ENOMEM;
	new->tag_set = kzalloc(sizeof(*new->tag_set), GFP_KERNEL);
	if (!new->tag_set)
		goto out_list_del;

	ret = blk_mq_alloc_sq_tag_set(new->tag_set, &mtd_mq_ops, 2,
			BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING);
	if (ret)
		goto out_kfree_tag_set;
	
	lim.logical_block_size = tr->blksize;
	if (tr->discard)
		lim.max_hw_discard_sectors = UINT_MAX;

	/* Create gendisk */
	gd = blk_mq_alloc_disk(new->tag_set, &lim, new);
	if (IS_ERR(gd)) {
		ret = PTR_ERR(gd);
		goto out_free_tag_set;
	}

	new->disk = gd;
	new->rq = new->disk->queue;
	gd->private_data = new;
	gd->major = tr->major;
	gd->first_minor = (new->devnum) << tr->part_bits;
	gd->minors = 1 << tr->part_bits;
	gd->fops = &mtd_block_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);
		gd->flags |= GENHD_FL_NO_PART;
	}

	set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);

	/* Create the request queue */
	spin_lock_init(&new->queue_lock);
	INIT_LIST_HEAD(&new->rq_list);

	if (tr->flush)
		blk_queue_write_cache(new->rq, true, false);

	blk_queue_flag_set(QUEUE_FLAG_NONROT, new->rq);
	blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, new->rq);

	gd->queue = new->rq;

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

	ret = device_add_disk(&new->mtd->dev, gd, NULL);
	if (ret)
		goto out_cleanup_disk;

	if (new->disk_attributes) {
		ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
					new->disk_attributes);
		WARN_ON(ret);
	}
	return 0;

out_cleanup_disk:
	put_disk(new->disk);
out_free_tag_set:
	blk_mq_free_tag_set(new->tag_set);
out_kfree_tag_set:
	kfree(new->tag_set);
out_list_del:
	list_del(&new->list);
	return ret;
}

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

	lockdep_assert_held(&mtd_table_mutex);

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

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

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

	/* freeze+quiesce queue to ensure all requests are flushed */
	blk_mq_freeze_queue(old->rq);
	blk_mq_quiesce_queue(old->rq);
	blk_mq_unquiesce_queue(old->rq);
	blk_mq_unfreeze_queue(old->rq);

	/* If the device is currently open, tell trans driver to close it,
		then put mtd device, and don't touch it again */
	mutex_lock(&old->lock);
	if (old->open) {
		if (old->tr->release)
			old->tr->release(old);
		__put_mtd_device(old->mtd);
	}

	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 || mtd->type == MTD_UBIVOLUME)
		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);

	ret = register_blkdev(tr->major, tr->name);
	if (ret < 0) {
		printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
		       tr->name, tr->major, ret);
		return ret;
	}

	if (ret)
		tr->major = ret;

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

	INIT_LIST_HEAD(&tr->devs);

	mutex_lock(&mtd_table_mutex);
	list_add(&tr->list, &blktrans_majors);
	mtd_for_each_device(mtd)
		if (mtd->type != MTD_ABSENT && mtd->type != MTD_UBIVOLUME)
			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);

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

	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
fd534e9b	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4	2	/*
a1452a37	3	* Interface to Linux block layer for MTD 'translation layers'.
1da177e4	4	*
a1452a37	5	* Copyright © 2003-2010 David Woodhouse <dwmw2@infradead.org>
1da177e4 LT	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>
891b7c5f	16	#include <linux/blk-mq.h>
1da177e4 LT	17	#include <linux/blkpg.h>
	18	#include <linux/spinlock.h>
	19	#include <linux/hdreg.h>
48b19268	20	#include <linux/mutex.h>
7c0f6ba6	21	#include <linux/uaccess.h>
1da177e4	22
356d70f1	23	#include "mtdcore.h"
1da177e4	24
356d70f1	25	static LIST_HEAD(blktrans_majors);
048d8719	26
7f53f12f	27	static void blktrans_dev_release(struct kref *kref)
048d8719 ML	28	{
	29	struct mtd_blktrans_dev *dev =
	30	container_of(kref, struct mtd_blktrans_dev, ref);
	31
8b9ab626	32	put_disk(dev->disk);
891b7c5f JA	33	blk_mq_free_tag_set(dev->tag_set);
891b7c5f JA	34	kfree(dev->tag_set);
048d8719 ML	35	list_del(&dev->list);
	36	kfree(dev);
	37	}
	38
7f53f12f	39	static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
048d8719	40	{
048d8719	41	kref_put(&dev->ref, blktrans_dev_release);
048d8719	42	}
1da177e4	43
1da177e4	44
2a842aca	45	static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr,
1da177e4 LT	46	struct mtd_blktrans_dev *dev,
	47	struct request *req)
	48	{
786d4e01 CH	49	struct req_iterator iter;
786d4e01 CH	50	struct bio_vec bvec;
1da177e4 LT	51	unsigned long block, nsect;
	52	char *buf;
	53
83096ebf	54	block = blk_rq_pos(req) << 9 >> tr->blkshift;
1011c1b9	55	nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
1da177e4	56
82baa324 CH	57	switch (req_op(req)) {
82baa324 CH	58	case REQ_OP_FLUSH:
2a842aca CH	59	if (tr->flush(dev))
	60	return BLK_STS_IOERR;
	61	return BLK_STS_OK;
aebf526b	62	case REQ_OP_DISCARD:
2a842aca CH	63	if (tr->discard(dev, block, nsect))
	64	return BLK_STS_IOERR;
	65	return BLK_STS_OK;
aebf526b	66	case REQ_OP_READ:
34ab96e6 CH	67	buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
	68	for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
	69	if (tr->readsect(dev, block, buf)) {
	70	kunmap(bio_page(req->bio));
2a842aca	71	return BLK_STS_IOERR;
34ab96e6 CH	72	}
	73	}
	74	kunmap(bio_page(req->bio));
786d4e01 CH	75
	76	rq_for_each_segment(bvec, req, iter)
	77	flush_dcache_page(bvec.bv_page);
2a842aca	78	return BLK_STS_OK;
aebf526b	79	case REQ_OP_WRITE:
1da177e4	80	if (!tr->writesect)
2a842aca	81	return BLK_STS_IOERR;
1da177e4	82
786d4e01 CH	83	rq_for_each_segment(bvec, req, iter)
	84	flush_dcache_page(bvec.bv_page);
	85
34ab96e6 CH	86	buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
	87	for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
	88	if (tr->writesect(dev, block, buf)) {
	89	kunmap(bio_page(req->bio));
2a842aca	90	return BLK_STS_IOERR;
34ab96e6 CH	91	}
	92	}
	93	kunmap(bio_page(req->bio));
9a515447	94	return BLK_STS_OK;
aebf526b	95	default:
2a842aca	96	return BLK_STS_IOERR;
1da177e4 LT	97	}
	98	}
	99
c7519dbf JL	100	int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
c7519dbf JL	101	{
7bf7e370	102	return dev->bg_stop;
c7519dbf JL	103	}
	104	EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
	105
891b7c5f JA	106	static struct request mtd_next_request(struct mtd_blktrans_dev dev)
	107	{
	108	struct request *rq;
	109
	110	rq = list_first_entry_or_null(&dev->rq_list, struct request, queuelist);
	111	if (rq) {
	112	list_del_init(&rq->queuelist);
	113	blk_mq_start_request(rq);
	114	return rq;
	115	}
	116
	117	return NULL;
	118	}
	119
	120	static void mtd_blktrans_work(struct mtd_blktrans_dev *dev)
	121	__releases(&dev->queue_lock)
	122	__acquires(&dev->queue_lock)
1da177e4	123	{
c7519dbf	124	struct mtd_blktrans_ops *tr = dev->tr;
1498ada7	125	struct request *req = NULL;
c7519dbf	126	int background_done = 0;
1da177e4	127
22a8578f	128	while (1) {
2a842aca	129	blk_status_t res;
1da177e4	130
7bf7e370	131	dev->bg_stop = false;
891b7c5f	132	if (!req && !(req = mtd_next_request(dev))) {
c7519dbf	133	if (tr->background && !background_done) {
891b7c5f	134	spin_unlock_irq(&dev->queue_lock);
c7519dbf JL	135	mutex_lock(&dev->lock);
	136	tr->background(dev);
	137	mutex_unlock(&dev->lock);
891b7c5f	138	spin_lock_irq(&dev->queue_lock);
c7519dbf JL	139	/*
	140	* Do background processing just once per idle
	141	* period.
	142	*/
7bf7e370	143	background_done = !dev->bg_stop;
c7519dbf JL	144	continue;
c7519dbf JL	145	}
22a8578f	146	break;
1da177e4 LT	147	}
1da177e4 LT	148
891b7c5f	149	spin_unlock_irq(&dev->queue_lock);
1da177e4	150
48b19268	151	mutex_lock(&dev->lock);
a8638622	152	res = do_blktrans_request(dev->tr, dev, req);
48b19268	153	mutex_unlock(&dev->lock);
1da177e4	154
891b7c5f JA	155	if (!blk_update_request(req, res, blk_rq_cur_bytes(req))) {
891b7c5f JA	156	__blk_mq_end_request(req, res);
1498ada7	157	req = NULL;
891b7c5f	158	}
c7519dbf JL	159
c7519dbf JL	160	background_done = 0;
ca6263a0	161	cond_resched();
891b7c5f	162	spin_lock_irq(&dev->queue_lock);
1da177e4	163	}
1da177e4 LT	164	}
1da177e4 LT	165
891b7c5f JA	166	static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx,
891b7c5f JA	167	const struct blk_mq_queue_data *bd)
1da177e4	168	{
048d8719	169	struct mtd_blktrans_dev *dev;
048d8719	170
891b7c5f JA	171	dev = hctx->queue->queuedata;
	172	if (!dev) {
	173	blk_mq_start_request(bd->rq);
	174	return BLK_STS_IOERR;
	175	}
	176
	177	spin_lock_irq(&dev->queue_lock);
	178	list_add_tail(&bd->rq->queuelist, &dev->rq_list);
	179	mtd_blktrans_work(dev);
	180	spin_unlock_irq(&dev->queue_lock);
1da177e4	181
891b7c5f	182	return BLK_STS_OK;
048d8719	183	}
1da177e4	184
05bdb996	185	static int blktrans_open(struct gendisk *disk, blk_mode_t mode)
1da177e4	186	{
d32e2bf8	187	struct mtd_blktrans_dev *dev = disk->private_data;
008c751e	188	int ret = 0;
048d8719	189
ee28b420	190	kref_get(&dev->ref);
048d8719	191
f3c63795	192	mutex_lock(&dev->lock);
048d8719	193
342ff28f	194	if (dev->open)
048d8719	195	goto unlock;
048d8719	196
008c751e ML	197	__module_get(dev->tr->owner);
008c751e ML	198
94735ec4 AB	199	if (!dev->mtd)
	200	goto unlock;
	201
	202	if (dev->tr->open) {
	203	ret = dev->tr->open(dev);
	204	if (ret)
	205	goto error_put;
008c751e	206	}
048d8719	207
94735ec4 AB	208	ret = __get_mtd_device(dev->mtd);
	209	if (ret)
	210	goto error_release;
05bdb996	211	dev->writable = mode & BLK_OPEN_WRITE;
94735ec4	212
048d8719	213	unlock:
342ff28f	214	dev->open++;
048d8719	215	mutex_unlock(&dev->lock);
1da177e4	216	return ret;
94735ec4 AB	217
	218	error_release:
	219	if (dev->tr->release)
	220	dev->tr->release(dev);
	221	error_put:
	222	module_put(dev->tr->owner);
94735ec4 AB	223	mutex_unlock(&dev->lock);
	224	blktrans_dev_put(dev);
	225	return ret;
1da177e4 LT	226	}
1da177e4 LT	227
ae220766	228	static void blktrans_release(struct gendisk *disk)
1da177e4	229	{
ee28b420	230	struct mtd_blktrans_dev *dev = disk->private_data;
1da177e4	231
f3c63795	232	mutex_lock(&dev->lock);
048d8719	233
008c751e	234	if (--dev->open)
048d8719 ML	235	goto unlock;
048d8719 ML	236
008c751e ML	237	module_put(dev->tr->owner);
	238
	239	if (dev->mtd) {
a8ca889e AV	240	if (dev->tr->release)
a8ca889e AV	241	dev->tr->release(dev);
008c751e ML	242	__put_mtd_device(dev->mtd);
008c751e ML	243	}
048d8719 ML	244	unlock:
	245	mutex_unlock(&dev->lock);
	246	blktrans_dev_put(dev);
1da177e4 LT	247	}
1da177e4 LT	248
a885c8c4 CH	249	static int blktrans_getgeo(struct block_device bdev, struct hd_geometry geo)
a885c8c4 CH	250	{
37b143d1	251	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
048d8719 ML	252	int ret = -ENXIO;
048d8719 ML	253
048d8719	254	mutex_lock(&dev->lock);
a885c8c4	255
048d8719 ML	256	if (!dev->mtd)
	257	goto unlock;
	258
c4a3f13c	259	ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY;
048d8719 ML	260	unlock:
048d8719 ML	261	mutex_unlock(&dev->lock);
048d8719	262	return ret;
a885c8c4	263	}
1da177e4	264
9329c5eb	265	static const struct block_device_operations mtd_block_ops = {
1da177e4	266	.owner = THIS_MODULE,
af0e2a0a AV	267	.open = blktrans_open,
af0e2a0a AV	268	.release = blktrans_release,
a885c8c4	269	.getgeo = blktrans_getgeo,
1da177e4 LT	270	};
1da177e4 LT	271
891b7c5f JA	272	static const struct blk_mq_ops mtd_mq_ops = {
	273	.queue_rq = mtd_queue_rq,
	274	};
	275
1da177e4 LT	276	int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
	277	{
	278	struct mtd_blktrans_ops *tr = new->tr;
71a928c0	279	struct mtd_blktrans_dev *d;
3ec44e52	280	struct queue_limits lim = { };
1da177e4 LT	281	int last_devnum = -1;
1da177e4 LT	282	struct gendisk *gd;
a8638622	283	int ret;
1da177e4	284
f214eebf	285	lockdep_assert_held(&mtd_table_mutex);
1da177e4	286
71a928c0	287	list_for_each_entry(d, &tr->devs, list) {
1da177e4 LT	288	if (new->devnum == -1) {
	289	/* Use first free number */
	290	if (d->devnum != last_devnum+1) {
	291	/* Found a free devnum. Plug it in here */
	292	new->devnum = last_devnum+1;
	293	list_add_tail(&new->list, &d->list);
	294	goto added;
	295	}
	296	} else if (d->devnum == new->devnum) {
	297	/* Required number taken */
	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) \|\|
560a3915	315	(tr->part_bits && new->devnum >= 27 * 26))
6966bb92	316	return ret;
1da177e4	317
1da177e4 LT	318	list_add_tail(&new->list, &tr->devs);
1da177e4 LT	319	added:
048d8719	320
ce37ab42	321	mutex_init(&new->lock);
048d8719	322	kref_init(&new->ref);
1da177e4 LT	323	if (!tr->writesect)
	324	new->readonly = 1;
	325
a8638622	326	ret = -ENOMEM;
6966bb92 CH	327	new->tag_set = kzalloc(sizeof(*new->tag_set), GFP_KERNEL);
	328	if (!new->tag_set)
	329	goto out_list_del;
a8638622	330
6966bb92 CH	331	ret = blk_mq_alloc_sq_tag_set(new->tag_set, &mtd_mq_ops, 2,
	332	BLK_MQ_F_SHOULD_MERGE \| BLK_MQ_F_BLOCKING);
	333	if (ret)
	334	goto out_kfree_tag_set;
3ec44e52 CH	335
	336	lim.logical_block_size = tr->blksize;
	337	if (tr->discard)
	338	lim.max_hw_discard_sectors = UINT_MAX;
6966bb92 CH	339
6966bb92 CH	340	/* Create gendisk */
3ec44e52	341	gd = blk_mq_alloc_disk(new->tag_set, &lim, new);
6966bb92 CH	342	if (IS_ERR(gd)) {
	343	ret = PTR_ERR(gd);
	344	goto out_free_tag_set;
	345	}
a8638622 ML	346
a8638622 ML	347	new->disk = gd;
07a719f8	348	new->rq = new->disk->queue;
a8638622	349	gd->private_data = new;
1da177e4 LT	350	gd->major = tr->major;
1da177e4 LT	351	gd->first_minor = (new->devnum) << tr->part_bits;
6966bb92	352	gd->minors = 1 << tr->part_bits;
9329c5eb	353	gd->fops = &mtd_block_ops;
97894cda	354
17f81f9d	355	if (tr->part_bits) {
65a8de36 TP	356	if (new->devnum < 26)
	357	snprintf(gd->disk_name, sizeof(gd->disk_name),
	358	"%s%c", tr->name, 'a' + new->devnum);
	359	else
	360	snprintf(gd->disk_name, sizeof(gd->disk_name),
	361	"%s%c%c", tr->name,
	362	'a' - 1 + new->devnum / 26,
	363	'a' + new->devnum % 26);
17f81f9d	364	} else {
65a8de36 TP	365	snprintf(gd->disk_name, sizeof(gd->disk_name),
65a8de36 TP	366	"%s%d", tr->name, new->devnum);
17f81f9d CH	367	gd->flags \|= GENHD_FL_NO_PART;
17f81f9d CH	368	}
1da177e4	369
2ce401d5	370	set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
1da177e4	371
a8638622 ML	372	/* Create the request queue */
a8638622 ML	373	spin_lock_init(&new->queue_lock);
891b7c5f	374	INIT_LIST_HEAD(&new->rq_list);
a8638622	375
566c0d6a	376	if (tr->flush)
fec3ff5d	377	blk_queue_write_cache(new->rq, true, false);
566c0d6a	378
8b904b5b BVA	379	blk_queue_flag_set(QUEUE_FLAG_NONROT, new->rq);
8b904b5b BVA	380	blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, new->rq);
16f7eca5	381
a8638622 ML	382	gd->queue = new->rq;
a8638622 ML	383
1da177e4 LT	384	if (new->readonly)
	385	set_disk_ro(gd, 1);
	386
83b863f4 LC	387	ret = device_add_disk(&new->mtd->dev, gd, NULL);
	388	if (ret)
	389	goto out_cleanup_disk;
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;
6966bb92	397
83b863f4	398	out_cleanup_disk:
8b9ab626	399	put_disk(new->disk);
6966bb92 CH	400	out_free_tag_set:
	401	blk_mq_free_tag_set(new->tag_set);
	402	out_kfree_tag_set:
891b7c5f	403	kfree(new->tag_set);
6966bb92	404	out_list_del:
a8638622	405	list_del(&new->list);
a8638622	406	return ret;
1da177e4 LT	407	}
	408
	409	int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
	410	{
048d8719 ML	411	unsigned long flags;
048d8719 ML	412
f214eebf	413	lockdep_assert_held(&mtd_table_mutex);
1da177e4	414
026ec578 ML	415	if (old->disk_attributes)
	416	sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
	417	old->disk_attributes);
	418
dba76c03 ML	419	/* Stop new requests to arrive */
	420	del_gendisk(old->disk);
	421
048d8719 ML	422	/* Kill current requests */
	423	spin_lock_irqsave(&old->queue_lock, flags);
	424	old->rq->queuedata = NULL;
048d8719	425	spin_unlock_irqrestore(&old->queue_lock, flags);
048d8719	426
891b7c5f JA	427	/* freeze+quiesce queue to ensure all requests are flushed */
	428	blk_mq_freeze_queue(old->rq);
	429	blk_mq_quiesce_queue(old->rq);
	430	blk_mq_unquiesce_queue(old->rq);
	431	blk_mq_unfreeze_queue(old->rq);
	432
008c751e ML	433	/* If the device is currently open, tell trans driver to close it,
008c751e ML	434	then put mtd device, and don't touch it again */
048d8719	435	mutex_lock(&old->lock);
008c751e ML	436	if (old->open) {
	437	if (old->tr->release)
	438	old->tr->release(old);
	439	__put_mtd_device(old->mtd);
048d8719 ML	440	}
048d8719 ML	441
048d8719 ML	442	old->mtd = NULL;
	443
	444	mutex_unlock(&old->lock);
	445	blktrans_dev_put(old);
1da177e4 LT	446	return 0;
	447	}
	448
	449	static void blktrans_notify_remove(struct mtd_info *mtd)
	450	{
71a928c0 CM	451	struct mtd_blktrans_ops *tr;
71a928c0 CM	452	struct mtd_blktrans_dev dev, next;
1da177e4	453
71a928c0 CM	454	list_for_each_entry(tr, &blktrans_majors, list)
71a928c0 CM	455	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4 LT	456	if (dev->mtd == mtd)
1da177e4 LT	457	tr->remove_dev(dev);
1da177e4 LT	458	}
	459
	460	static void blktrans_notify_add(struct mtd_info *mtd)
	461	{
71a928c0	462	struct mtd_blktrans_ops *tr;
1da177e4	463
a43bdc37	464	if (mtd->type == MTD_ABSENT \|\| mtd->type == MTD_UBIVOLUME)
1da177e4 LT	465	return;
1da177e4 LT	466
71a928c0	467	list_for_each_entry(tr, &blktrans_majors, list)
1da177e4	468	tr->add_mtd(tr, mtd);
1da177e4 LT	469	}
	470
	471	static struct mtd_notifier blktrans_notifier = {
	472	.add = blktrans_notify_add,
	473	.remove = blktrans_notify_remove,
	474	};
97894cda	475
1da177e4 LT	476	int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
1da177e4 LT	477	{
f1332ba2 BH	478	struct mtd_info *mtd;
f1332ba2 BH	479	int ret;
1da177e4	480
97894cda	481	/* Register the notifier if/when the first device type is
1da177e4 LT	482	registered, to prevent the link/init ordering from fucking
	483	us over. */
	484	if (!blktrans_notifier.list.next)
	485	register_mtd_user(&blktrans_notifier);
	486
1da177e4	487	ret = register_blkdev(tr->major, tr->name);
6fe4c590	488	if (ret < 0) {
1da177e4 LT	489	printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
1da177e4 LT	490	tr->name, tr->major, ret);
1da177e4 LT	491	return ret;
1da177e4 LT	492	}
eae9acd1	493
6fe4c590 FL	494	if (ret)
	495	tr->major = ret;
	496
19187672	497	tr->blkshift = ffs(tr->blksize) - 1;
1da177e4	498
1da177e4	499	INIT_LIST_HEAD(&tr->devs);
1da177e4	500
962bf783 DCZX	501	mutex_lock(&mtd_table_mutex);
962bf783 DCZX	502	list_add(&tr->list, &blktrans_majors);
f1332ba2	503	mtd_for_each_device(mtd)
a43bdc37	504	if (mtd->type != MTD_ABSENT && mtd->type != MTD_UBIVOLUME)
f1332ba2	505	tr->add_mtd(tr, mtd);
48b19268	506	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	507	return 0;
	508	}
	509
	510	int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
	511	{
71a928c0	512	struct mtd_blktrans_dev dev, next;
1da177e4	513
48b19268	514	mutex_lock(&mtd_table_mutex);
1da177e4	515
1da177e4 LT	516	/* Remove it from the list of active majors */
	517	list_del(&tr->list);
	518
71a928c0	519	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4	520	tr->remove_dev(dev);
1da177e4	521
48b19268	522	mutex_unlock(&mtd_table_mutex);
b7abb051	523	unregister_blkdev(tr->major, tr->name);
1da177e4	524
373ebfbf	525	BUG_ON(!list_empty(&tr->devs));
1da177e4 LT	526	return 0;
	527	}
	528
	529	static void __exit mtd_blktrans_exit(void)
	530	{
	531	/* No race here -- if someone's currently in register_mtd_blktrans
	532	we're screwed anyway. */
	533	if (blktrans_notifier.list.next)
	534	unregister_mtd_user(&blktrans_notifier);
	535	}
	536
	537	module_exit(mtd_blktrans_exit);
	538
	539	EXPORT_SYMBOL_GPL(register_mtd_blktrans);
	540	EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
	541	EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
	542	EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
	543
	544	MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
	545	MODULE_LICENSE("GPL");
	546	MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");