/* * $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; nsect = req->current_nr_sectors; buf = req->buffer; if (!(req->flags & REQ_CMD)) return 0; if (block + nsect > get_capacity(req->rq_disk)) return 0; switch(rq_data_dir(req)) { case READ: for (; nsect > 0; nsect--, block++, buf += 512) if (tr->readsect(dev, block, buf)) return 0; return 1; case WRITE: if (!tr->writesect) return 0; for (; nsect > 0; nsect--, block++, buf += 512) if (tr->writesect(dev, block, buf)) return 0; return 1; default: printk(KERN_NOTICE "Unknown request %ld\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(¤t->sighand->siglock); sigfillset(¤t->blocked); recalc_sigpending(); spin_unlock_irq(¤t->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 * new->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 = kmalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL); if (!tr->blkcore_priv) return -ENOMEM; memset(tr->blkcore_priv, 0, sizeof(*tr->blkcore_priv)); 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; 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'");