/* * $Id: mtd_blkdevs.c,v 1.27 2005/11/07 11:14:20 gleixner Exp $ * * (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 <asm/uaccess.h> static LIST_HEAD(blktrans_majors); extern struct mutex mtd_table_mutex;extern struct mtd_info *mtd_table[]; struct mtd_blkcore_priv {	struct completion thread_dead;	int exiting;	wait_queue_head_t thread_wq;	struct request_queue *rq;	spinlock_t queue_lock;}; 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 = req->sector << 9 >> tr->blkshift;	nsect = req->current_nr_sectors << 9 >> tr->blkshift; 	buf = req->buffer; 	if (!blk_fs_request(req))		return 0; 	if (req->sector + req->current_nr_sectors > get_capacity(req->rq_disk))		return 0; 	switch(rq_data_dir(req)) {	case READ:		for (; nsect > 0; nsect--, block++, buf += tr->blksize)			if (tr->readsect(dev, block, buf))				return 0;		return 1; 	case WRITE:		if (!tr->writesect)			return 0; 		for (; nsect > 0; nsect--, block++, buf += tr->blksize)			if (tr->writesect(dev, block, buf))				return 0;		return 1; 	default:		printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));		return 0;	}} static int mtd_blktrans_thread(void *arg){	struct mtd_blktrans_ops *tr = arg;	struct request_queue *rq = tr->blkcore_priv->rq; 	/* we might get involved when memory gets low, so use PF_MEMALLOC */	current->flags |= PF_MEMALLOC | PF_NOFREEZE; 	daemonize("%sd", tr->name); 	/* daemonize() doesn't do this for us since some kernel threads	   actually want to deal with signals. We can't just call	   exit_sighand() since that'll cause an oops when we finally	   do exit. */	spin_lock_irq(&current->sighand->siglock);	sigfillset(&current->blocked);	recalc_sigpending();	spin_unlock_irq(&current->sighand->siglock); 	spin_lock_irq(rq->queue_lock); 	while (!tr->blkcore_priv->exiting) {		struct request *req;		struct mtd_blktrans_dev *dev;		int res = 0;		DECLARE_WAITQUEUE(wait, current); 		req = elv_next_request(rq); 		if (!req) {			add_wait_queue(&tr->blkcore_priv->thread_wq, &wait);			set_current_state(TASK_INTERRUPTIBLE); 			spin_unlock_irq(rq->queue_lock); 			schedule();			remove_wait_queue(&tr->blkcore_priv->thread_wq, &wait); 			spin_lock_irq(rq->queue_lock); 			continue;		} 		dev = req->rq_disk->private_data;		tr = dev->tr; 		spin_unlock_irq(rq->queue_lock); 		mutex_lock(&dev->lock);		res = do_blktrans_request(tr, dev, req);		mutex_unlock(&dev->lock); 		spin_lock_irq(rq->queue_lock); 		end_request(req, res);	}	spin_unlock_irq(rq->queue_lock); 	complete_and_exit(&tr->blkcore_priv->thread_dead, 0);} static void mtd_blktrans_request(struct request_queue *rq){	struct mtd_blktrans_ops *tr = rq->queuedata;	wake_up(&tr->blkcore_priv->thread_wq);}  static int blktrans_open(struct inode *i, struct file *f){	struct mtd_blktrans_dev *dev;	struct mtd_blktrans_ops *tr;	int ret = -ENODEV; 	dev = i->i_bdev->bd_disk->private_data;	tr = dev->tr; 	if (!try_module_get(dev->mtd->owner))		goto out; 	if (!try_module_get(tr->owner))		goto out_tr; 	/* FIXME: Locking. A hot pluggable device can go away	   (del_mtd_device can be called for it) without its module	   being unloaded. */	dev->mtd->usecount++; 	ret = 0;	if (tr->open && (ret = tr->open(dev))) {		dev->mtd->usecount--;		module_put(dev->mtd->owner);	out_tr:		module_put(tr->owner);	} out:	return ret;} static int blktrans_release(struct inode *i, struct file *f){	struct mtd_blktrans_dev *dev;	struct mtd_blktrans_ops *tr;	int ret = 0; 	dev = i->i_bdev->bd_disk->private_data;	tr = dev->tr; 	if (tr->release)		ret = tr->release(dev); 	if (!ret) {		dev->mtd->usecount--;		module_put(dev->mtd->owner);		module_put(tr->owner);	} 	return ret;} static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo){	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data; 	if (dev->tr->getgeo)		return dev->tr->getgeo(dev, geo);	return -ENOTTY;} static int blktrans_ioctl(struct inode *inode, struct file *file,			      unsigned int cmd, unsigned long arg){	struct mtd_blktrans_dev *dev = inode->i_bdev->bd_disk->private_data;	struct mtd_blktrans_ops *tr = dev->tr; 	switch (cmd) {	case BLKFLSBUF:		if (tr->flush)			return tr->flush(dev);		/* The core code did the work, we had nothing to do. */		return 0;	default:		return -ENOTTY;	}} 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 list_head *this;	int last_devnum = -1;	struct gendisk *gd; 	if (!!mutex_trylock(&mtd_table_mutex)) {		mutex_unlock(&mtd_table_mutex);		BUG();	} 	list_for_each(this, &tr->devs) {		struct mtd_blktrans_dev *d = list_entry(this, struct mtd_blktrans_dev, 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;	}	if (new->devnum == -1)		new->devnum = last_devnum+1; 	if ((new->devnum << tr->part_bits) > 256) {		return -EBUSY;	} 	mutex_init(&new->lock);	list_add_tail(&new->list, &tr->devs); added:	if (!tr->writesect)		new->readonly = 1; 	gd = alloc_disk(1 << tr->part_bits);	if (!gd) {		list_del(&new->list);		return -ENOMEM;	}	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); 	/* 2.5 has capacity in units of 512 bytes while still	   having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */	set_capacity(gd, (new->size * tr->blksize) >> 9); 	gd->private_data = new;	new->blkcore_priv = gd;	gd->queue = tr->blkcore_priv->rq; 	if (new->readonly)		set_disk_ro(gd, 1); 	add_disk(gd); 	return 0;} int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old){	if (!!mutex_trylock(&mtd_table_mutex)) {		mutex_unlock(&mtd_table_mutex);		BUG();	} 	list_del(&old->list); 	del_gendisk(old->blkcore_priv);	put_disk(old->blkcore_priv); 	return 0;} static void blktrans_notify_remove(struct mtd_info *mtd){	struct list_head *this, *this2, *next; 	list_for_each(this, &blktrans_majors) {		struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list); 		list_for_each_safe(this2, next, &tr->devs) {			struct mtd_blktrans_dev *dev = list_entry(this2, struct mtd_blktrans_dev, list); 			if (dev->mtd == mtd)				tr->remove_dev(dev);		}	}} static void blktrans_notify_add(struct mtd_info *mtd){	struct list_head *this; 	if (mtd->type == MTD_ABSENT)		return; 	list_for_each(this, &blktrans_majors) {		struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, 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){	int ret, i; 	/* 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); 	tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);	if (!tr->blkcore_priv)		return -ENOMEM; 	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);		kfree(tr->blkcore_priv);		mutex_unlock(&mtd_table_mutex);		return ret;	}	spin_lock_init(&tr->blkcore_priv->queue_lock);	init_completion(&tr->blkcore_priv->thread_dead);	init_waitqueue_head(&tr->blkcore_priv->thread_wq); 	tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);	if (!tr->blkcore_priv->rq) {		unregister_blkdev(tr->major, tr->name);		kfree(tr->blkcore_priv);		mutex_unlock(&mtd_table_mutex);		return -ENOMEM;	} 	tr->blkcore_priv->rq->queuedata = tr;	blk_queue_hardsect_size(tr->blkcore_priv->rq, tr->blksize);	tr->blkshift = ffs(tr->blksize) - 1; 	ret = kernel_thread(mtd_blktrans_thread, tr, CLONE_KERNEL);	if (ret < 0) {		blk_cleanup_queue(tr->blkcore_priv->rq);		unregister_blkdev(tr->major, tr->name);		kfree(tr->blkcore_priv);		mutex_unlock(&mtd_table_mutex);		return ret;	} 	INIT_LIST_HEAD(&tr->devs);	list_add(&tr->list, &blktrans_majors); 	for (i=0; i<MAX_MTD_DEVICES; i++) {		if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)			tr->add_mtd(tr, mtd_table[i]);	} 	mutex_unlock(&mtd_table_mutex); 	return 0;} int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr){	struct list_head *this, *next; 	mutex_lock(&mtd_table_mutex); 	/* Clean up the kernel thread */	tr->blkcore_priv->exiting = 1;	wake_up(&tr->blkcore_priv->thread_wq);	wait_for_completion(&tr->blkcore_priv->thread_dead); 	/* Remove it from the list of active majors */	list_del(&tr->list); 	list_for_each_safe(this, next, &tr->devs) {		struct mtd_blktrans_dev *dev = list_entry(this, struct mtd_blktrans_dev, list);		tr->remove_dev(dev);	} 	blk_cleanup_queue(tr->blkcore_priv->rq);	unregister_blkdev(tr->major, tr->name); 	mutex_unlock(&mtd_table_mutex); 	kfree(tr->blkcore_priv); 	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'");