linux/drivers/mtd/mtd_blkdevs.c
Christoph Hellwig a885c8c431 [PATCH] Add block_device_operations.getgeo block device method
HDIO_GETGEO is implemented in most block drivers, and all of them have to
duplicate the code to copy the structure to userspace, as well as getting
the start sector.  This patch moves that to common code [1] and adds a
->getgeo method to fill out the raw kernel hd_geometry structure.  For many
drivers this means ->ioctl can go away now.

[1] the s390 block drivers are odd in this respect.  xpram sets ->start
    to 4 always which seems more than odd, and the dasd driver shifts
    the start offset around, probably because of it's non-standard
    sector size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@suse.de>
Cc: <mike.miller@hp.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Cc: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:54 -08:00

476 lines
11 KiB
C

/*
* $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 <asm/semaphore.h>
#include <asm/uaccess.h>
static LIST_HEAD(blktrans_majors);
extern struct semaphore 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(&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);
down(&dev->sem);
res = do_blktrans_request(tr, dev, req);
up(&dev->sem);
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 (!down_trylock(&mtd_table_mutex)) {
up(&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;
}
init_MUTEX(&new->sem);
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 (!down_trylock(&mtd_table_mutex)) {
up(&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));
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'");