linux/drivers/mtd/mtd_blkdevs.c

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/*
* (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/freezer.h>
#include <linux/spinlock.h>
#include <linux/hdreg.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/kthread.h>
#include <asm/uaccess.h>
#include "mtdcore.h"
static LIST_HEAD(blktrans_majors);
struct mtd_blkcore_priv {
struct task_struct *thread;
struct request_queue *rq;
spinlock_t queue_lock;
};
static int blktrans_discard_request(struct request_queue *q,
struct request *req)
{
req->cmd_type = REQ_TYPE_LINUX_BLOCK;
req->cmd[0] = REQ_LB_OP_DISCARD;
return 0;
}
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: convert to pos and nr_sectors accessors With recent cleanups, there is no place where low level driver directly manipulates request fields. This means that the 'hard' request fields always equal the !hard fields. Convert all rq->sectors, nr_sectors and current_nr_sectors references to accessors. While at it, drop superflous blk_rq_pos() < 0 test in swim.c. [ Impact: use pos and nr_sectors accessors ] Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Tested-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Grant Likely <grant.likely@secretlab.ca> Tested-by: Adrian McMenamin <adrian@mcmen.demon.co.uk> Acked-by: Adrian McMenamin <adrian@mcmen.demon.co.uk> Acked-by: Mike Miller <mike.miller@hp.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Borislav Petkov <petkovbb@googlemail.com> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: Eric Moore <Eric.Moore@lsi.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Paul Clements <paul.clements@steeleye.com> Cc: Tim Waugh <tim@cyberelk.net> Cc: Jeff Garzik <jgarzik@pobox.com> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Alex Dubov <oakad@yahoo.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Dario Ballabio <ballabio_dario@emc.com> Cc: David S. Miller <davem@davemloft.net> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: unsik Kim <donari75@gmail.com> Cc: Laurent Vivier <Laurent@lvivier.info> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-07 13:24:39 +00:00
block = blk_rq_pos(req) << 9 >> tr->blkshift;
nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
buf = req->buffer;
if (req->cmd_type == REQ_TYPE_LINUX_BLOCK &&
req->cmd[0] == REQ_LB_OP_DISCARD)
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return tr->discard(dev, block, nsect);
if (!blk_fs_request(req))
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return -EIO;
block: convert to pos and nr_sectors accessors With recent cleanups, there is no place where low level driver directly manipulates request fields. This means that the 'hard' request fields always equal the !hard fields. Convert all rq->sectors, nr_sectors and current_nr_sectors references to accessors. While at it, drop superflous blk_rq_pos() < 0 test in swim.c. [ Impact: use pos and nr_sectors accessors ] Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Tested-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Grant Likely <grant.likely@secretlab.ca> Tested-by: Adrian McMenamin <adrian@mcmen.demon.co.uk> Acked-by: Adrian McMenamin <adrian@mcmen.demon.co.uk> Acked-by: Mike Miller <mike.miller@hp.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Borislav Petkov <petkovbb@googlemail.com> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: Eric Moore <Eric.Moore@lsi.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Paul Clements <paul.clements@steeleye.com> Cc: Tim Waugh <tim@cyberelk.net> Cc: Jeff Garzik <jgarzik@pobox.com> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Alex Dubov <oakad@yahoo.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Dario Ballabio <ballabio_dario@emc.com> Cc: David S. Miller <davem@davemloft.net> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: unsik Kim <donari75@gmail.com> Cc: Laurent Vivier <Laurent@lvivier.info> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-07 13:24:39 +00:00
if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
get_capacity(req->rq_disk))
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return -EIO;
switch(rq_data_dir(req)) {
case READ:
for (; nsect > 0; nsect--, block++, buf += tr->blksize)
if (tr->readsect(dev, block, buf))
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return -EIO;
return 0;
case WRITE:
if (!tr->writesect)
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return -EIO;
for (; nsect > 0; nsect--, block++, buf += tr->blksize)
if (tr->writesect(dev, block, buf))
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return -EIO;
return 0;
default:
printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
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return -EIO;
}
}
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;
spin_lock_irq(rq->queue_lock);
while (!kthread_should_stop()) {
struct request *req;
struct mtd_blktrans_dev *dev;
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int res;
req = elv_next_request(rq);
if (!req) {
set_current_state(TASK_INTERRUPTIBLE);
spin_unlock_irq(rq->queue_lock);
schedule();
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);
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__blk_end_request_cur(req, res);
}
spin_unlock_irq(rq->queue_lock);
return 0;
}
static void mtd_blktrans_request(struct request_queue *rq)
{
struct mtd_blktrans_ops *tr = rq->queuedata;
wake_up_process(tr->blkcore_priv->thread);
}
static int blktrans_open(struct block_device *bdev, fmode_t mode)
{
struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
struct mtd_blktrans_ops *tr = dev->tr;
int ret = -ENODEV;
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 gendisk *disk, fmode_t mode)
{
struct mtd_blktrans_dev *dev = disk->private_data;
struct mtd_blktrans_ops *tr = dev->tr;
int ret = 0;
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 block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
struct mtd_blktrans_dev *dev = 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;
}
}
static struct block_device_operations mtd_blktrans_ops = {
.owner = THIS_MODULE,
.open = blktrans_open,
.release = blktrans_release,
.locked_ioctl = blktrans_ioctl,
.getgeo = blktrans_getgeo,
};
int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
{
struct mtd_blktrans_ops *tr = new->tr;
struct mtd_blktrans_dev *d;
int last_devnum = -1;
struct gendisk *gd;
if (mutex_trylock(&mtd_table_mutex)) {
mutex_unlock(&mtd_table_mutex);
BUG();
}
list_for_each_entry(d, &tr->devs, 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;
}
list_add_tail(&new->list, &tr->devs);
added:
mutex_init(&new->lock);
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;
gd->driverfs_dev = new->mtd->dev.parent;
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 mtd_blktrans_ops *tr;
struct mtd_blktrans_dev *dev, *next;
list_for_each_entry(tr, &blktrans_majors, list)
list_for_each_entry_safe(dev, next, &tr->devs, list)
if (dev->mtd == mtd)
tr->remove_dev(dev);
}
static void blktrans_notify_add(struct mtd_info *mtd)
{
struct mtd_blktrans_ops *tr;
if (mtd->type == MTD_ABSENT)
return;
list_for_each_entry(tr, &blktrans_majors, 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);
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);
if (tr->discard)
blk_queue_set_discard(tr->blkcore_priv->rq,
blktrans_discard_request);
tr->blkshift = ffs(tr->blksize) - 1;
tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
"%sd", tr->name);
if (IS_ERR(tr->blkcore_priv->thread)) {
int ret = PTR_ERR(tr->blkcore_priv->thread);
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 mtd_blktrans_dev *dev, *next;
mutex_lock(&mtd_table_mutex);
/* Clean up the kernel thread */
kthread_stop(tr->blkcore_priv->thread);
/* Remove it from the list of active majors */
list_del(&tr->list);
list_for_each_entry_safe(dev, next, &tr->devs, 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'");