2005-04-16 16:20:36 -06:00
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/*
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2005-07-29 13:42:07 -06:00
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* $Id: mtd_blkdevs.c,v 1.26 2005/07/29 19:42:04 tpoynor Exp $
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2005-04-16 16:20:36 -06:00
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*
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* (C) 2003 David Woodhouse <dwmw2@infradead.org>
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*
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* Interface to Linux 2.5 block layer for MTD 'translation layers'.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/list.h>
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#include <linux/fs.h>
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#include <linux/mtd/blktrans.h>
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#include <linux/mtd/mtd.h>
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#include <linux/blkdev.h>
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#include <linux/blkpg.h>
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#include <linux/spinlock.h>
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#include <linux/hdreg.h>
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#include <linux/init.h>
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#include <asm/semaphore.h>
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#include <asm/uaccess.h>
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static LIST_HEAD(blktrans_majors);
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extern struct semaphore mtd_table_mutex;
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extern struct mtd_info *mtd_table[];
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struct mtd_blkcore_priv {
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struct completion thread_dead;
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int exiting;
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wait_queue_head_t thread_wq;
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struct request_queue *rq;
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spinlock_t queue_lock;
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};
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static int do_blktrans_request(struct mtd_blktrans_ops *tr,
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struct mtd_blktrans_dev *dev,
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struct request *req)
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{
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unsigned long block, nsect;
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char *buf;
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block = req->sector;
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nsect = req->current_nr_sectors;
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buf = req->buffer;
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if (!(req->flags & REQ_CMD))
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return 0;
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if (block + nsect > get_capacity(req->rq_disk))
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return 0;
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switch(rq_data_dir(req)) {
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case READ:
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for (; nsect > 0; nsect--, block++, buf += 512)
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if (tr->readsect(dev, block, buf))
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return 0;
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return 1;
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case WRITE:
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if (!tr->writesect)
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return 0;
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for (; nsect > 0; nsect--, block++, buf += 512)
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if (tr->writesect(dev, block, buf))
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return 0;
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return 1;
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default:
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printk(KERN_NOTICE "Unknown request %ld\n", rq_data_dir(req));
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return 0;
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}
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}
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static int mtd_blktrans_thread(void *arg)
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{
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struct mtd_blktrans_ops *tr = arg;
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struct request_queue *rq = tr->blkcore_priv->rq;
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/* we might get involved when memory gets low, so use PF_MEMALLOC */
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current->flags |= PF_MEMALLOC | PF_NOFREEZE;
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daemonize("%sd", tr->name);
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/* daemonize() doesn't do this for us since some kernel threads
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actually want to deal with signals. We can't just call
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exit_sighand() since that'll cause an oops when we finally
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do exit. */
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spin_lock_irq(¤t->sighand->siglock);
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sigfillset(¤t->blocked);
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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spin_lock_irq(rq->queue_lock);
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while (!tr->blkcore_priv->exiting) {
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struct request *req;
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struct mtd_blktrans_dev *dev;
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int res = 0;
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DECLARE_WAITQUEUE(wait, current);
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req = elv_next_request(rq);
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if (!req) {
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add_wait_queue(&tr->blkcore_priv->thread_wq, &wait);
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set_current_state(TASK_INTERRUPTIBLE);
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spin_unlock_irq(rq->queue_lock);
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schedule();
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remove_wait_queue(&tr->blkcore_priv->thread_wq, &wait);
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spin_lock_irq(rq->queue_lock);
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continue;
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}
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dev = req->rq_disk->private_data;
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tr = dev->tr;
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spin_unlock_irq(rq->queue_lock);
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down(&dev->sem);
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res = do_blktrans_request(tr, dev, req);
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up(&dev->sem);
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spin_lock_irq(rq->queue_lock);
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end_request(req, res);
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}
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spin_unlock_irq(rq->queue_lock);
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complete_and_exit(&tr->blkcore_priv->thread_dead, 0);
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}
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static void mtd_blktrans_request(struct request_queue *rq)
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{
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struct mtd_blktrans_ops *tr = rq->queuedata;
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wake_up(&tr->blkcore_priv->thread_wq);
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}
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static int blktrans_open(struct inode *i, struct file *f)
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{
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struct mtd_blktrans_dev *dev;
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struct mtd_blktrans_ops *tr;
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int ret = -ENODEV;
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dev = i->i_bdev->bd_disk->private_data;
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tr = dev->tr;
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if (!try_module_get(dev->mtd->owner))
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goto out;
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if (!try_module_get(tr->owner))
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goto out_tr;
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/* FIXME: Locking. A hot pluggable device can go away
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(del_mtd_device can be called for it) without its module
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being unloaded. */
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dev->mtd->usecount++;
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ret = 0;
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if (tr->open && (ret = tr->open(dev))) {
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dev->mtd->usecount--;
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module_put(dev->mtd->owner);
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out_tr:
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module_put(tr->owner);
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}
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out:
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return ret;
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}
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static int blktrans_release(struct inode *i, struct file *f)
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{
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struct mtd_blktrans_dev *dev;
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struct mtd_blktrans_ops *tr;
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int ret = 0;
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dev = i->i_bdev->bd_disk->private_data;
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tr = dev->tr;
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if (tr->release)
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ret = tr->release(dev);
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if (!ret) {
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dev->mtd->usecount--;
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module_put(dev->mtd->owner);
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module_put(tr->owner);
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}
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return ret;
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}
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static int blktrans_ioctl(struct inode *inode, struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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struct mtd_blktrans_dev *dev = inode->i_bdev->bd_disk->private_data;
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struct mtd_blktrans_ops *tr = dev->tr;
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switch (cmd) {
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case BLKFLSBUF:
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if (tr->flush)
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return tr->flush(dev);
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/* The core code did the work, we had nothing to do. */
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return 0;
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case HDIO_GETGEO:
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if (tr->getgeo) {
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struct hd_geometry g;
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int ret;
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memset(&g, 0, sizeof(g));
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ret = tr->getgeo(dev, &g);
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if (ret)
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return ret;
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g.start = get_start_sect(inode->i_bdev);
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if (copy_to_user((void __user *)arg, &g, sizeof(g)))
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return -EFAULT;
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return 0;
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} /* else */
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default:
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return -ENOTTY;
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}
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}
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struct block_device_operations mtd_blktrans_ops = {
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.owner = THIS_MODULE,
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.open = blktrans_open,
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.release = blktrans_release,
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.ioctl = blktrans_ioctl,
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};
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int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
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{
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struct mtd_blktrans_ops *tr = new->tr;
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struct list_head *this;
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int last_devnum = -1;
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struct gendisk *gd;
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if (!down_trylock(&mtd_table_mutex)) {
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up(&mtd_table_mutex);
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BUG();
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}
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list_for_each(this, &tr->devs) {
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struct mtd_blktrans_dev *d = list_entry(this, struct mtd_blktrans_dev, list);
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if (new->devnum == -1) {
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/* Use first free number */
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if (d->devnum != last_devnum+1) {
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/* Found a free devnum. Plug it in here */
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new->devnum = last_devnum+1;
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list_add_tail(&new->list, &d->list);
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goto added;
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}
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} else if (d->devnum == new->devnum) {
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/* Required number taken */
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return -EBUSY;
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} else if (d->devnum > new->devnum) {
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/* Required number was free */
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list_add_tail(&new->list, &d->list);
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goto added;
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}
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last_devnum = d->devnum;
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}
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if (new->devnum == -1)
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new->devnum = last_devnum+1;
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if ((new->devnum << tr->part_bits) > 256) {
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return -EBUSY;
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}
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init_MUTEX(&new->sem);
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list_add_tail(&new->list, &tr->devs);
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added:
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if (!tr->writesect)
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new->readonly = 1;
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gd = alloc_disk(1 << tr->part_bits);
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if (!gd) {
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list_del(&new->list);
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return -ENOMEM;
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}
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gd->major = tr->major;
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gd->first_minor = (new->devnum) << tr->part_bits;
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gd->fops = &mtd_blktrans_ops;
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2005-07-29 13:42:07 -06:00
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if (tr->part_bits)
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if (new->devnum < 26)
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snprintf(gd->disk_name, sizeof(gd->disk_name),
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"%s%c", tr->name, 'a' + new->devnum);
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else
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snprintf(gd->disk_name, sizeof(gd->disk_name),
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"%s%c%c", tr->name,
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'a' - 1 + new->devnum / 26,
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'a' + new->devnum % 26);
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else
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snprintf(gd->disk_name, sizeof(gd->disk_name),
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"%s%d", tr->name, new->devnum);
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2005-04-16 16:20:36 -06:00
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/* 2.5 has capacity in units of 512 bytes while still
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having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
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set_capacity(gd, (new->size * new->blksize) >> 9);
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gd->private_data = new;
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new->blkcore_priv = gd;
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gd->queue = tr->blkcore_priv->rq;
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if (new->readonly)
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set_disk_ro(gd, 1);
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add_disk(gd);
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return 0;
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}
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int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
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{
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if (!down_trylock(&mtd_table_mutex)) {
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up(&mtd_table_mutex);
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BUG();
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}
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list_del(&old->list);
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del_gendisk(old->blkcore_priv);
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put_disk(old->blkcore_priv);
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return 0;
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}
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static void blktrans_notify_remove(struct mtd_info *mtd)
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{
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struct list_head *this, *this2, *next;
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list_for_each(this, &blktrans_majors) {
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struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
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list_for_each_safe(this2, next, &tr->devs) {
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struct mtd_blktrans_dev *dev = list_entry(this2, struct mtd_blktrans_dev, list);
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if (dev->mtd == mtd)
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tr->remove_dev(dev);
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}
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}
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}
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static void blktrans_notify_add(struct mtd_info *mtd)
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{
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struct list_head *this;
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if (mtd->type == MTD_ABSENT)
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return;
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list_for_each(this, &blktrans_majors) {
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struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
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tr->add_mtd(tr, mtd);
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}
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}
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static struct mtd_notifier blktrans_notifier = {
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.add = blktrans_notify_add,
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.remove = blktrans_notify_remove,
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};
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int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
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{
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int ret, i;
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/* Register the notifier if/when the first device type is
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registered, to prevent the link/init ordering from fucking
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us over. */
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if (!blktrans_notifier.list.next)
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register_mtd_user(&blktrans_notifier);
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tr->blkcore_priv = kmalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
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if (!tr->blkcore_priv)
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return -ENOMEM;
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memset(tr->blkcore_priv, 0, sizeof(*tr->blkcore_priv));
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|
|
|
down(&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);
|
|
|
|
up(&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);
|
|
|
|
up(&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);
|
|
|
|
up(&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]);
|
|
|
|
}
|
|
|
|
|
|
|
|
up(&mtd_table_mutex);
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
|
|
|
|
{
|
|
|
|
struct list_head *this, *next;
|
|
|
|
|
|
|
|
down(&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);
|
|
|
|
|
|
|
|
up(&mtd_table_mutex);
|
|
|
|
|
|
|
|
kfree(tr->blkcore_priv);
|
|
|
|
|
|
|
|
if (!list_empty(&tr->devs))
|
|
|
|
BUG();
|
|
|
|
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'");
|