[linux-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 DEFINE_MUTEX(blktrans_ref_mutex);

static 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);
	blk_mq_free_tag_set(dev->tag_set);
	kfree(dev->tag_set);
	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;
}

static 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 blk_status_t 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;

	if (req_op(req) == REQ_OP_FLUSH) {
		if (tr->flush(dev))
			return BLK_STS_IOERR;
		return BLK_STS_OK;
	}

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

	switch (req_op(req)) {
	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_flush_dcache_pages(req);
		return BLK_STS_OK;
	case REQ_OP_WRITE:
		if (!tr->writesect)
			return BLK_STS_IOERR;

		rq_flush_dcache_pages(req);
		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;
		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 block_device *bdev, fmode_t mode)
{
	struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
	int ret = 0;

	if (!dev)
		return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/

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

	if (dev->open)
		goto unlock;

	kref_get(&dev->ref);
	__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->file_mode = mode;

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

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

static void blktrans_release(struct gendisk *disk, fmode_t mode)
{
	struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);

	if (!dev)
		return;

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

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

	kref_put(&dev->ref, blktrans_dev_release);
	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);
	mutex_unlock(&mtd_table_mutex);
	blktrans_dev_put(dev);
}

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) : -ENOTTY;
unlock:
	mutex_unlock(&dev->lock);
	blktrans_dev_put(dev);
	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;
	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_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);

	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);

	new->tag_set = kzalloc(sizeof(*new->tag_set), GFP_KERNEL);
	if (!new->tag_set)
		goto error3;

	new->rq = blk_mq_init_sq_queue(new->tag_set, &mtd_mq_ops, 2,
				BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING);
	if (IS_ERR(new->rq)) {
		ret = PTR_ERR(new->rq);
		new->rq = NULL;
		goto error4;
	}

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

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

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

	if (tr->discard) {
		blk_queue_flag_set(QUEUE_FLAG_DISCARD, new->rq);
		blk_queue_max_discard_sectors(new->rq, UINT_MAX);
	}

	gd->queue = new->rq;

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

	device_add_disk(&new->mtd->dev, gd, NULL);

	if (new->disk_attributes) {
		ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
					new->disk_attributes);
		WARN_ON(ret);
	}
	return 0;
error4:
	kfree(new->tag_set);
error3:
	put_disk(new->disk);
error2:
	list_del(&new->list);
error1:
	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();
	}

	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)
		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 < 0) {
		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;
	}

	if (ret)
		tr->major = 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
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 ML	26	static DEFINE_MUTEX(blktrans_ref_mutex);
048d8719 ML	27
7f53f12f	28	static void blktrans_dev_release(struct kref *kref)
048d8719 ML	29	{
	30	struct mtd_blktrans_dev *dev =
	31	container_of(kref, struct mtd_blktrans_dev, ref);
	32
	33	dev->disk->private_data = NULL;
e4d64cab	34	blk_cleanup_queue(dev->rq);
891b7c5f JA	35	blk_mq_free_tag_set(dev->tag_set);
891b7c5f JA	36	kfree(dev->tag_set);
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
7f53f12f	57	static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
048d8719 ML	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	64
2a842aca	65	static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr,
1da177e4 LT	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;
1da177e4	74
2a842aca CH	75	if (req_op(req) == REQ_OP_FLUSH) {
	76	if (tr->flush(dev))
	77	return BLK_STS_IOERR;
	78	return BLK_STS_OK;
	79	}
566c0d6a	80
83096ebf TH	81	if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
83096ebf TH	82	get_capacity(req->rq_disk))
2a842aca	83	return BLK_STS_IOERR;
1da177e4	84
aebf526b CH	85	switch (req_op(req)) {
aebf526b CH	86	case REQ_OP_DISCARD:
2a842aca CH	87	if (tr->discard(dev, block, nsect))
	88	return BLK_STS_IOERR;
	89	return BLK_STS_OK;
aebf526b	90	case REQ_OP_READ:
34ab96e6 CH	91	buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
	92	for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
	93	if (tr->readsect(dev, block, buf)) {
	94	kunmap(bio_page(req->bio));
2a842aca	95	return BLK_STS_IOERR;
34ab96e6 CH	96	}
	97	}
	98	kunmap(bio_page(req->bio));
2d4dc890	99	rq_flush_dcache_pages(req);
2a842aca	100	return BLK_STS_OK;
aebf526b	101	case REQ_OP_WRITE:
1da177e4	102	if (!tr->writesect)
2a842aca	103	return BLK_STS_IOERR;
1da177e4	104
2d4dc890	105	rq_flush_dcache_pages(req);
34ab96e6 CH	106	buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
	107	for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
	108	if (tr->writesect(dev, block, buf)) {
	109	kunmap(bio_page(req->bio));
2a842aca	110	return BLK_STS_IOERR;
34ab96e6 CH	111	}
	112	}
	113	kunmap(bio_page(req->bio));
9a515447	114	return BLK_STS_OK;
aebf526b	115	default:
2a842aca	116	return BLK_STS_IOERR;
1da177e4 LT	117	}
	118	}
	119
c7519dbf JL	120	int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
c7519dbf JL	121	{
7bf7e370	122	return dev->bg_stop;
c7519dbf JL	123	}
	124	EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
	125
891b7c5f JA	126	static struct request mtd_next_request(struct mtd_blktrans_dev dev)
	127	{
	128	struct request *rq;
	129
	130	rq = list_first_entry_or_null(&dev->rq_list, struct request, queuelist);
	131	if (rq) {
	132	list_del_init(&rq->queuelist);
	133	blk_mq_start_request(rq);
	134	return rq;
	135	}
	136
	137	return NULL;
	138	}
	139
	140	static void mtd_blktrans_work(struct mtd_blktrans_dev *dev)
	141	__releases(&dev->queue_lock)
	142	__acquires(&dev->queue_lock)
1da177e4	143	{
c7519dbf	144	struct mtd_blktrans_ops *tr = dev->tr;
1498ada7	145	struct request *req = NULL;
c7519dbf	146	int background_done = 0;
1da177e4	147
22a8578f	148	while (1) {
2a842aca	149	blk_status_t res;
1da177e4	150
7bf7e370	151	dev->bg_stop = false;
891b7c5f	152	if (!req && !(req = mtd_next_request(dev))) {
c7519dbf	153	if (tr->background && !background_done) {
891b7c5f	154	spin_unlock_irq(&dev->queue_lock);
c7519dbf JL	155	mutex_lock(&dev->lock);
	156	tr->background(dev);
	157	mutex_unlock(&dev->lock);
891b7c5f	158	spin_lock_irq(&dev->queue_lock);
c7519dbf JL	159	/*
	160	* Do background processing just once per idle
	161	* period.
	162	*/
7bf7e370	163	background_done = !dev->bg_stop;
c7519dbf JL	164	continue;
c7519dbf JL	165	}
22a8578f	166	break;
1da177e4 LT	167	}
1da177e4 LT	168
891b7c5f	169	spin_unlock_irq(&dev->queue_lock);
1da177e4	170
48b19268	171	mutex_lock(&dev->lock);
a8638622	172	res = do_blktrans_request(dev->tr, dev, req);
48b19268	173	mutex_unlock(&dev->lock);
1da177e4	174
891b7c5f JA	175	if (!blk_update_request(req, res, blk_rq_cur_bytes(req))) {
891b7c5f JA	176	__blk_mq_end_request(req, res);
1498ada7	177	req = NULL;
891b7c5f	178	}
c7519dbf JL	179
c7519dbf JL	180	background_done = 0;
891b7c5f	181	spin_lock_irq(&dev->queue_lock);
1da177e4	182	}
1da177e4 LT	183	}
1da177e4 LT	184
891b7c5f JA	185	static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx,
891b7c5f JA	186	const struct blk_mq_queue_data *bd)
1da177e4	187	{
048d8719	188	struct mtd_blktrans_dev *dev;
048d8719	189
891b7c5f JA	190	dev = hctx->queue->queuedata;
	191	if (!dev) {
	192	blk_mq_start_request(bd->rq);
	193	return BLK_STS_IOERR;
	194	}
	195
	196	spin_lock_irq(&dev->queue_lock);
	197	list_add_tail(&bd->rq->queuelist, &dev->rq_list);
	198	mtd_blktrans_work(dev);
	199	spin_unlock_irq(&dev->queue_lock);
1da177e4	200
891b7c5f	201	return BLK_STS_OK;
048d8719	202	}
1da177e4	203
af0e2a0a	204	static int blktrans_open(struct block_device *bdev, fmode_t mode)
1da177e4	205	{
048d8719	206	struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
008c751e	207	int ret = 0;
048d8719 ML	208
048d8719 ML	209	if (!dev)
6e9624b8	210	return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
048d8719	211
073db4a5	212	mutex_lock(&mtd_table_mutex);
f3c63795	213	mutex_lock(&dev->lock);
048d8719	214
342ff28f	215	if (dev->open)
048d8719	216	goto unlock;
048d8719	217
008c751e ML	218	kref_get(&dev->ref);
	219	__module_get(dev->tr->owner);
	220
94735ec4 AB	221	if (!dev->mtd)
	222	goto unlock;
	223
	224	if (dev->tr->open) {
	225	ret = dev->tr->open(dev);
	226	if (ret)
	227	goto error_put;
008c751e	228	}
048d8719	229
94735ec4 AB	230	ret = __get_mtd_device(dev->mtd);
	231	if (ret)
	232	goto error_release;
70d5098a	233	dev->file_mode = mode;
94735ec4	234
048d8719	235	unlock:
342ff28f	236	dev->open++;
048d8719	237	mutex_unlock(&dev->lock);
f3c63795	238	mutex_unlock(&mtd_table_mutex);
048d8719	239	blktrans_dev_put(dev);
1da177e4	240	return ret;
94735ec4 AB	241
	242	error_release:
	243	if (dev->tr->release)
	244	dev->tr->release(dev);
	245	error_put:
	246	module_put(dev->tr->owner);
	247	kref_put(&dev->ref, blktrans_dev_release);
	248	mutex_unlock(&dev->lock);
f3c63795	249	mutex_unlock(&mtd_table_mutex);
94735ec4 AB	250	blktrans_dev_put(dev);
94735ec4 AB	251	return ret;
1da177e4 LT	252	}
1da177e4 LT	253
db2a144b	254	static void blktrans_release(struct gendisk *disk, fmode_t mode)
1da177e4	255	{
048d8719	256	struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
1da177e4	257
048d8719	258	if (!dev)
db2a144b	259	return;
1da177e4	260
073db4a5	261	mutex_lock(&mtd_table_mutex);
f3c63795	262	mutex_lock(&dev->lock);
048d8719	263
008c751e	264	if (--dev->open)
048d8719 ML	265	goto unlock;
048d8719 ML	266
008c751e ML	267	kref_put(&dev->ref, blktrans_dev_release);
	268	module_put(dev->tr->owner);
	269
	270	if (dev->mtd) {
a8ca889e AV	271	if (dev->tr->release)
a8ca889e AV	272	dev->tr->release(dev);
008c751e ML	273	__put_mtd_device(dev->mtd);
008c751e ML	274	}
048d8719 ML	275	unlock:
048d8719 ML	276	mutex_unlock(&dev->lock);
f3c63795	277	mutex_unlock(&mtd_table_mutex);
048d8719	278	blktrans_dev_put(dev);
1da177e4 LT	279	}
1da177e4 LT	280
a885c8c4 CH	281	static int blktrans_getgeo(struct block_device bdev, struct hd_geometry geo)
a885c8c4 CH	282	{
048d8719 ML	283	struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
	284	int ret = -ENXIO;
	285
	286	if (!dev)
	287	return ret;
	288
	289	mutex_lock(&dev->lock);
a885c8c4	290
048d8719 ML	291	if (!dev->mtd)
	292	goto unlock;
	293
c4a3f13c	294	ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY;
048d8719 ML	295	unlock:
	296	mutex_unlock(&dev->lock);
	297	blktrans_dev_put(dev);
	298	return ret;
a885c8c4	299	}
1da177e4	300
9329c5eb	301	static const struct block_device_operations mtd_block_ops = {
1da177e4	302	.owner = THIS_MODULE,
af0e2a0a AV	303	.open = blktrans_open,
af0e2a0a AV	304	.release = blktrans_release,
a885c8c4	305	.getgeo = blktrans_getgeo,
1da177e4 LT	306	};
1da177e4 LT	307
891b7c5f JA	308	static const struct blk_mq_ops mtd_mq_ops = {
	309	.queue_rq = mtd_queue_rq,
	310	};
	311
1da177e4 LT	312	int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
	313	{
	314	struct mtd_blktrans_ops *tr = new->tr;
71a928c0	315	struct mtd_blktrans_dev *d;
1da177e4 LT	316	int last_devnum = -1;
1da177e4 LT	317	struct gendisk *gd;
a8638622	318	int ret;
1da177e4	319
b3561ea9	320	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	321	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	322	BUG();
	323	}
	324
048d8719	325	mutex_lock(&blktrans_ref_mutex);
71a928c0	326	list_for_each_entry(d, &tr->devs, list) {
1da177e4 LT	327	if (new->devnum == -1) {
	328	/* Use first free number */
	329	if (d->devnum != last_devnum+1) {
	330	/* Found a free devnum. Plug it in here */
	331	new->devnum = last_devnum+1;
	332	list_add_tail(&new->list, &d->list);
	333	goto added;
	334	}
	335	} else if (d->devnum == new->devnum) {
	336	/* Required number taken */
048d8719	337	mutex_unlock(&blktrans_ref_mutex);
1da177e4 LT	338	return -EBUSY;
	339	} else if (d->devnum > new->devnum) {
	340	/* Required number was free */
	341	list_add_tail(&new->list, &d->list);
	342	goto added;
97894cda	343	}
1da177e4 LT	344	last_devnum = d->devnum;
1da177e4 LT	345	}
a8638622 ML	346
a8638622 ML	347	ret = -EBUSY;
1da177e4 LT	348	if (new->devnum == -1)
	349	new->devnum = last_devnum+1;
	350
4d3a8534 BH	351	/* Check that the device and any partitions will get valid
	352	* minor numbers and that the disk naming code below can cope
	353	* with this number. */
	354	if (new->devnum > (MINORMASK >> tr->part_bits) \|\|
048d8719 ML	355	(tr->part_bits && new->devnum >= 27 * 26)) {
048d8719 ML	356	mutex_unlock(&blktrans_ref_mutex);
a8638622	357	goto error1;
048d8719	358	}
1da177e4	359
1da177e4 LT	360	list_add_tail(&new->list, &tr->devs);
1da177e4 LT	361	added:
048d8719 ML	362	mutex_unlock(&blktrans_ref_mutex);
048d8719 ML	363
ce37ab42	364	mutex_init(&new->lock);
048d8719	365	kref_init(&new->ref);
1da177e4 LT	366	if (!tr->writesect)
	367	new->readonly = 1;
	368
a8638622 ML	369	/* Create gendisk */
a8638622 ML	370	ret = -ENOMEM;
1da177e4	371	gd = alloc_disk(1 << tr->part_bits);
a8638622 ML	372
	373	if (!gd)
	374	goto error2;
	375
	376	new->disk = gd;
	377	gd->private_data = new;
1da177e4 LT	378	gd->major = tr->major;
1da177e4 LT	379	gd->first_minor = (new->devnum) << tr->part_bits;
9329c5eb	380	gd->fops = &mtd_block_ops;
97894cda	381
65a8de36 TP	382	if (tr->part_bits)
	383	if (new->devnum < 26)
	384	snprintf(gd->disk_name, sizeof(gd->disk_name),
	385	"%s%c", tr->name, 'a' + new->devnum);
	386	else
	387	snprintf(gd->disk_name, sizeof(gd->disk_name),
	388	"%s%c%c", tr->name,
	389	'a' - 1 + new->devnum / 26,
	390	'a' + new->devnum % 26);
	391	else
	392	snprintf(gd->disk_name, sizeof(gd->disk_name),
	393	"%s%d", tr->name, new->devnum);
1da177e4	394
2ce401d5	395	set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
1da177e4	396
a8638622 ML	397	/* Create the request queue */
a8638622 ML	398	spin_lock_init(&new->queue_lock);
891b7c5f	399	INIT_LIST_HEAD(&new->rq_list);
a8638622	400
891b7c5f JA	401	new->tag_set = kzalloc(sizeof(*new->tag_set), GFP_KERNEL);
891b7c5f JA	402	if (!new->tag_set)
a8638622 ML	403	goto error3;
a8638622 ML	404
891b7c5f JA	405	new->rq = blk_mq_init_sq_queue(new->tag_set, &mtd_mq_ops, 2,
	406	BLK_MQ_F_SHOULD_MERGE \| BLK_MQ_F_BLOCKING);
	407	if (IS_ERR(new->rq)) {
	408	ret = PTR_ERR(new->rq);
	409	new->rq = NULL;
	410	goto error4;
	411	}
	412
566c0d6a	413	if (tr->flush)
fec3ff5d	414	blk_queue_write_cache(new->rq, true, false);
566c0d6a	415
a8638622 ML	416	new->rq->queuedata = new;
	417	blk_queue_logical_block_size(new->rq, tr->blksize);
	418
8b904b5b BVA	419	blk_queue_flag_set(QUEUE_FLAG_NONROT, new->rq);
8b904b5b BVA	420	blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, new->rq);
16f7eca5	421
115ee88c	422	if (tr->discard) {
8b904b5b	423	blk_queue_flag_set(QUEUE_FLAG_DISCARD, new->rq);
2bb4cd5c	424	blk_queue_max_discard_sectors(new->rq, UINT_MAX);
115ee88c	425	}
a8638622 ML	426
	427	gd->queue = new->rq;
	428
1da177e4 LT	429	if (new->readonly)
	430	set_disk_ro(gd, 1);
	431
fef912bf	432	device_add_disk(&new->mtd->dev, gd, NULL);
026ec578	433
133fa8c7 ML	434	if (new->disk_attributes) {
133fa8c7 ML	435	ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
026ec578	436	new->disk_attributes);
133fa8c7 ML	437	WARN_ON(ret);
133fa8c7 ML	438	}
1da177e4	439	return 0;
a8638622	440	error4:
891b7c5f	441	kfree(new->tag_set);
a8638622 ML	442	error3:
	443	put_disk(new->disk);
	444	error2:
	445	list_del(&new->list);
	446	error1:
a8638622	447	return ret;
1da177e4 LT	448	}
	449
	450	int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
	451	{
048d8719 ML	452	unsigned long flags;
048d8719 ML	453
b3561ea9	454	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	455	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	456	BUG();
	457	}
	458
026ec578 ML	459	if (old->disk_attributes)
	460	sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
	461	old->disk_attributes);
	462
dba76c03 ML	463	/* Stop new requests to arrive */
	464	del_gendisk(old->disk);
	465
048d8719 ML	466	/* Kill current requests */
	467	spin_lock_irqsave(&old->queue_lock, flags);
	468	old->rq->queuedata = NULL;
048d8719	469	spin_unlock_irqrestore(&old->queue_lock, flags);
048d8719	470
891b7c5f JA	471	/* freeze+quiesce queue to ensure all requests are flushed */
	472	blk_mq_freeze_queue(old->rq);
	473	blk_mq_quiesce_queue(old->rq);
	474	blk_mq_unquiesce_queue(old->rq);
	475	blk_mq_unfreeze_queue(old->rq);
	476
008c751e ML	477	/* If the device is currently open, tell trans driver to close it,
008c751e ML	478	then put mtd device, and don't touch it again */
048d8719	479	mutex_lock(&old->lock);
008c751e ML	480	if (old->open) {
	481	if (old->tr->release)
	482	old->tr->release(old);
	483	__put_mtd_device(old->mtd);
048d8719 ML	484	}
048d8719 ML	485
048d8719 ML	486	old->mtd = NULL;
	487
	488	mutex_unlock(&old->lock);
	489	blktrans_dev_put(old);
1da177e4 LT	490	return 0;
	491	}
	492
	493	static void blktrans_notify_remove(struct mtd_info *mtd)
	494	{
71a928c0 CM	495	struct mtd_blktrans_ops *tr;
71a928c0 CM	496	struct mtd_blktrans_dev dev, next;
1da177e4	497
71a928c0 CM	498	list_for_each_entry(tr, &blktrans_majors, list)
71a928c0 CM	499	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4 LT	500	if (dev->mtd == mtd)
1da177e4 LT	501	tr->remove_dev(dev);
1da177e4 LT	502	}
	503
	504	static void blktrans_notify_add(struct mtd_info *mtd)
	505	{
71a928c0	506	struct mtd_blktrans_ops *tr;
1da177e4 LT	507
	508	if (mtd->type == MTD_ABSENT)
	509	return;
	510
71a928c0	511	list_for_each_entry(tr, &blktrans_majors, list)
1da177e4	512	tr->add_mtd(tr, mtd);
1da177e4 LT	513	}
	514
	515	static struct mtd_notifier blktrans_notifier = {
	516	.add = blktrans_notify_add,
	517	.remove = blktrans_notify_remove,
	518	};
97894cda	519
1da177e4 LT	520	int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
1da177e4 LT	521	{
f1332ba2 BH	522	struct mtd_info *mtd;
f1332ba2 BH	523	int ret;
1da177e4	524
97894cda	525	/* Register the notifier if/when the first device type is
1da177e4 LT	526	registered, to prevent the link/init ordering from fucking
	527	us over. */
	528	if (!blktrans_notifier.list.next)
	529	register_mtd_user(&blktrans_notifier);
	530
1da177e4	531
48b19268	532	mutex_lock(&mtd_table_mutex);
1da177e4 LT	533
1da177e4 LT	534	ret = register_blkdev(tr->major, tr->name);
6fe4c590	535	if (ret < 0) {
1da177e4 LT	536	printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
1da177e4 LT	537	tr->name, tr->major, ret);
48b19268	538	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	539	return ret;
1da177e4 LT	540	}
eae9acd1	541
6fe4c590 FL	542	if (ret)
	543	tr->major = ret;
	544
19187672	545	tr->blkshift = ffs(tr->blksize) - 1;
1da177e4	546
1da177e4 LT	547	INIT_LIST_HEAD(&tr->devs);
	548	list_add(&tr->list, &blktrans_majors);
	549
f1332ba2 BH	550	mtd_for_each_device(mtd)
	551	if (mtd->type != MTD_ABSENT)
	552	tr->add_mtd(tr, mtd);
1da177e4	553
48b19268	554	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	555	return 0;
	556	}
	557
	558	int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
	559	{
71a928c0	560	struct mtd_blktrans_dev dev, next;
1da177e4	561
48b19268	562	mutex_lock(&mtd_table_mutex);
1da177e4	563
1da177e4 LT	564	/* Remove it from the list of active majors */
	565	list_del(&tr->list);
	566
71a928c0	567	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4	568	tr->remove_dev(dev);
1da177e4	569
1da177e4	570	unregister_blkdev(tr->major, tr->name);
48b19268	571	mutex_unlock(&mtd_table_mutex);
1da177e4	572
373ebfbf	573	BUG_ON(!list_empty(&tr->devs));
1da177e4 LT	574	return 0;
	575	}
	576
	577	static void __exit mtd_blktrans_exit(void)
	578	{
	579	/* No race here -- if someone's currently in register_mtd_blktrans
	580	we're screwed anyway. */
	581	if (blktrans_notifier.list.next)
	582	unregister_mtd_user(&blktrans_notifier);
	583	}
	584
	585	module_exit(mtd_blktrans_exit);
	586
	587	EXPORT_SYMBOL_GPL(register_mtd_blktrans);
	588	EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
	589	EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
	590	EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
	591
	592	MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
	593	MODULE_LICENSE("GPL");
	594	MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");