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![Alexey Dobriyan](/assets/img/avatar_default.png)
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
455 lines
10 KiB
C
455 lines
10 KiB
C
/*
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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/freezer.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 <linux/mutex.h>
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#include <linux/kthread.h>
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#include <asm/uaccess.h>
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#include "mtdcore.h"
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static LIST_HEAD(blktrans_majors);
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struct mtd_blkcore_priv {
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struct task_struct *thread;
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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 blktrans_discard_request(struct request_queue *q,
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struct request *req)
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{
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req->cmd_type = REQ_TYPE_LINUX_BLOCK;
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req->cmd[0] = REQ_LB_OP_DISCARD;
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return 0;
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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 = blk_rq_pos(req) << 9 >> tr->blkshift;
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nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
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buf = req->buffer;
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if (req->cmd_type == REQ_TYPE_LINUX_BLOCK &&
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req->cmd[0] == REQ_LB_OP_DISCARD)
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return tr->discard(dev, block, nsect);
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if (!blk_fs_request(req))
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return -EIO;
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if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
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get_capacity(req->rq_disk))
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return -EIO;
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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 += tr->blksize)
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if (tr->readsect(dev, block, buf))
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return -EIO;
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return 0;
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case WRITE:
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if (!tr->writesect)
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return -EIO;
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for (; nsect > 0; nsect--, block++, buf += tr->blksize)
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if (tr->writesect(dev, block, buf))
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return -EIO;
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return 0;
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default:
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printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
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return -EIO;
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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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struct request *req = NULL;
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/* we might get involved when memory gets low, so use PF_MEMALLOC */
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current->flags |= PF_MEMALLOC;
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spin_lock_irq(rq->queue_lock);
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while (!kthread_should_stop()) {
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struct mtd_blktrans_dev *dev;
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int res;
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if (!req && !(req = blk_fetch_request(rq))) {
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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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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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mutex_lock(&dev->lock);
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res = do_blktrans_request(tr, dev, req);
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mutex_unlock(&dev->lock);
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spin_lock_irq(rq->queue_lock);
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if (!__blk_end_request_cur(req, res))
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req = NULL;
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}
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if (req)
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__blk_end_request_all(req, -EIO);
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spin_unlock_irq(rq->queue_lock);
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return 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_process(tr->blkcore_priv->thread);
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}
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static int blktrans_open(struct block_device *bdev, fmode_t mode)
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{
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struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
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struct mtd_blktrans_ops *tr = dev->tr;
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int ret = -ENODEV;
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if (!get_mtd_device(NULL, dev->mtd->index))
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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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put_mtd_device(dev->mtd);
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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 gendisk *disk, fmode_t mode)
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{
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struct mtd_blktrans_dev *dev = disk->private_data;
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struct mtd_blktrans_ops *tr = dev->tr;
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int ret = 0;
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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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put_mtd_device(dev->mtd);
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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_getgeo(struct block_device *bdev, struct hd_geometry *geo)
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{
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struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
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if (dev->tr->getgeo)
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return dev->tr->getgeo(dev, geo);
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return -ENOTTY;
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}
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static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
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unsigned int cmd, unsigned long arg)
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{
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struct mtd_blktrans_dev *dev = 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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default:
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return -ENOTTY;
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}
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}
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static const 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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.locked_ioctl = blktrans_ioctl,
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.getgeo = blktrans_getgeo,
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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 mtd_blktrans_dev *d;
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int last_devnum = -1;
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struct gendisk *gd;
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if (mutex_trylock(&mtd_table_mutex)) {
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mutex_unlock(&mtd_table_mutex);
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BUG();
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}
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list_for_each_entry(d, &tr->devs, 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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list_add_tail(&new->list, &tr->devs);
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added:
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mutex_init(&new->lock);
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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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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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/* 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 * tr->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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gd->driverfs_dev = &new->mtd->dev;
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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 (mutex_trylock(&mtd_table_mutex)) {
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mutex_unlock(&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 mtd_blktrans_ops *tr;
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struct mtd_blktrans_dev *dev, *next;
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list_for_each_entry(tr, &blktrans_majors, list)
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list_for_each_entry_safe(dev, next, &tr->devs, 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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static void blktrans_notify_add(struct mtd_info *mtd)
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{
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struct mtd_blktrans_ops *tr;
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if (mtd->type == MTD_ABSENT)
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return;
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list_for_each_entry(tr, &blktrans_majors, list)
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tr->add_mtd(tr, mtd);
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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 = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
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if (!tr->blkcore_priv)
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return -ENOMEM;
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mutex_lock(&mtd_table_mutex);
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ret = register_blkdev(tr->major, tr->name);
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if (ret) {
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printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
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tr->name, tr->major, ret);
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kfree(tr->blkcore_priv);
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mutex_unlock(&mtd_table_mutex);
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return ret;
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}
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spin_lock_init(&tr->blkcore_priv->queue_lock);
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tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
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if (!tr->blkcore_priv->rq) {
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unregister_blkdev(tr->major, tr->name);
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kfree(tr->blkcore_priv);
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mutex_unlock(&mtd_table_mutex);
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return -ENOMEM;
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}
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tr->blkcore_priv->rq->queuedata = tr;
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blk_queue_logical_block_size(tr->blkcore_priv->rq, tr->blksize);
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if (tr->discard)
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blk_queue_set_discard(tr->blkcore_priv->rq,
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blktrans_discard_request);
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tr->blkshift = ffs(tr->blksize) - 1;
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tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
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"%sd", tr->name);
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if (IS_ERR(tr->blkcore_priv->thread)) {
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int ret = PTR_ERR(tr->blkcore_priv->thread);
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blk_cleanup_queue(tr->blkcore_priv->rq);
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unregister_blkdev(tr->major, tr->name);
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kfree(tr->blkcore_priv);
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mutex_unlock(&mtd_table_mutex);
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return ret;
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}
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INIT_LIST_HEAD(&tr->devs);
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list_add(&tr->list, &blktrans_majors);
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for (i=0; i<MAX_MTD_DEVICES; i++) {
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if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
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tr->add_mtd(tr, mtd_table[i]);
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}
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mutex_unlock(&mtd_table_mutex);
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return 0;
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}
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int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
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{
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struct mtd_blktrans_dev *dev, *next;
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mutex_lock(&mtd_table_mutex);
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/* Clean up the kernel thread */
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kthread_stop(tr->blkcore_priv->thread);
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/* Remove it from the list of active majors */
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list_del(&tr->list);
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list_for_each_entry_safe(dev, next, &tr->devs, list)
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tr->remove_dev(dev);
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blk_cleanup_queue(tr->blkcore_priv->rq);
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unregister_blkdev(tr->major, tr->name);
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mutex_unlock(&mtd_table_mutex);
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kfree(tr->blkcore_priv);
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BUG_ON(!list_empty(&tr->devs));
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return 0;
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}
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static void __exit mtd_blktrans_exit(void)
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{
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/* No race here -- if someone's currently in register_mtd_blktrans
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we're screwed anyway. */
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if (blktrans_notifier.list.next)
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unregister_mtd_user(&blktrans_notifier);
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}
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module_exit(mtd_blktrans_exit);
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EXPORT_SYMBOL_GPL(register_mtd_blktrans);
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EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
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EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
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EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
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MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");
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