--- /dev/null
+/*
+ * Interface to Linux block layer for MTD 'translation layers'.
+ *
+ * Copyright © 2003-2010 David Woodhouse <dwmw2@infradead.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+#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/mutex.h>
+#include <asm/uaccess.h>
+
+#include "mtdcore.h"
+
+static LIST_HEAD(blktrans_majors);
+static DEFINE_MUTEX(blktrans_ref_mutex);
+
+static void blktrans_dev_release(struct kref *kref)
+{
+ struct mtd_blktrans_dev *dev =
+ container_of(kref, struct mtd_blktrans_dev, ref);
+
+ dev->disk->private_data = NULL;
+ blk_cleanup_queue(dev->rq);
+ put_disk(dev->disk);
+ list_del(&dev->list);
+ kfree(dev);
+}
+
+static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
+{
+ struct mtd_blktrans_dev *dev;
+
+ mutex_lock(&blktrans_ref_mutex);
+ dev = disk->private_data;
+
+ if (!dev)
+ goto unlock;
+ kref_get(&dev->ref);
+unlock:
+ mutex_unlock(&blktrans_ref_mutex);
+ return dev;
+}
+
+static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
+{
+ mutex_lock(&blktrans_ref_mutex);
+ kref_put(&dev->ref, blktrans_dev_release);
+ mutex_unlock(&blktrans_ref_mutex);
+}
+
+
+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 = blk_rq_pos(req) << 9 >> tr->blkshift;
+ nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
+ buf = bio_data(req->bio);
+
+ if (req->cmd_type != REQ_TYPE_FS)
+ return -EIO;
+
+ if (req->cmd_flags & REQ_FLUSH)
+ return tr->flush(dev);
+
+ if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
+ get_capacity(req->rq_disk))
+ return -EIO;
+
+ if (req->cmd_flags & REQ_DISCARD)
+ return tr->discard(dev, block, nsect);
+
+ switch(rq_data_dir(req)) {
+ case READ:
+ for (; nsect > 0; nsect--, block++, buf += tr->blksize)
+ if (tr->readsect(dev, block, buf))
+ return -EIO;
+ rq_flush_dcache_pages(req);
+ return 0;
+ case WRITE:
+ if (!tr->writesect)
+ return -EIO;
+
+ rq_flush_dcache_pages(req);
+ for (; nsect > 0; nsect--, block++, buf += tr->blksize)
+ if (tr->writesect(dev, block, buf))
+ return -EIO;
+ return 0;
+ default:
+ printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
+ return -EIO;
+ }
+}
+
+int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
+{
+ return dev->bg_stop;
+}
+EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
+
+static void mtd_blktrans_work(struct work_struct *work)
+{
+ struct mtd_blktrans_dev *dev =
+ container_of(work, struct mtd_blktrans_dev, work);
+ struct mtd_blktrans_ops *tr = dev->tr;
+ struct request_queue *rq = dev->rq;
+ struct request *req = NULL;
+ int background_done = 0;
+
+ spin_lock_irq(rq->queue_lock);
+
+ while (1) {
+ int res;
+
+ dev->bg_stop = false;
+ if (!req && !(req = blk_fetch_request(rq))) {
+ if (tr->background && !background_done) {
+ spin_unlock_irq(rq->queue_lock);
+ mutex_lock(&dev->lock);
+ tr->background(dev);
+ mutex_unlock(&dev->lock);
+ spin_lock_irq(rq->queue_lock);
+ /*
+ * Do background processing just once per idle
+ * period.
+ */
+ background_done = !dev->bg_stop;
+ continue;
+ }
+ break;
+ }
+
+ spin_unlock_irq(rq->queue_lock);
+
+ mutex_lock(&dev->lock);
+ res = do_blktrans_request(dev->tr, dev, req);
+ mutex_unlock(&dev->lock);
+
+ spin_lock_irq(rq->queue_lock);
+
+ if (!__blk_end_request_cur(req, res))
+ req = NULL;
+
+ background_done = 0;
+ }
+
+ spin_unlock_irq(rq->queue_lock);
+}
+
+static void mtd_blktrans_request(struct request_queue *rq)
+{
+ struct mtd_blktrans_dev *dev;
+ struct request *req = NULL;
+
+ dev = rq->queuedata;
+
+ if (!dev)
+ while ((req = blk_fetch_request(rq)) != NULL)
+ __blk_end_request_all(req, -ENODEV);
+ else
+ queue_work(dev->wq, &dev->work);
+}
+
+static int blktrans_open(struct block_device *bdev, fmode_t mode)
+{
+ struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
+ int ret = 0;
+
+ if (!dev)
+ return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
+
+ mutex_lock(&dev->lock);
+ mutex_lock(&mtd_table_mutex);
+
+ if (dev->open)
+ goto unlock;
+
+ kref_get(&dev->ref);
+ __module_get(dev->tr->owner);
+
+ if (!dev->mtd)
+ goto unlock;
+
+ if (dev->tr->open) {
+ ret = dev->tr->open(dev);
+ if (ret)
+ goto error_put;
+ }
+
+ ret = __get_mtd_device(dev->mtd);
+ if (ret)
+ goto error_release;
+ dev->file_mode = mode;
+
+unlock:
+ dev->open++;
+ mutex_unlock(&mtd_table_mutex);
+ mutex_unlock(&dev->lock);
+ blktrans_dev_put(dev);
+ return ret;
+
+error_release:
+ if (dev->tr->release)
+ dev->tr->release(dev);
+error_put:
+ module_put(dev->tr->owner);
+ kref_put(&dev->ref, blktrans_dev_release);
+ mutex_unlock(&mtd_table_mutex);
+ mutex_unlock(&dev->lock);
+ blktrans_dev_put(dev);
+ return ret;
+}
+
+static void blktrans_release(struct gendisk *disk, fmode_t mode)
+{
+ struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
+
+ if (!dev)
+ return;
+
+ mutex_lock(&dev->lock);
+ mutex_lock(&mtd_table_mutex);
+
+ if (--dev->open)
+ goto unlock;
+
+ kref_put(&dev->ref, blktrans_dev_release);
+ module_put(dev->tr->owner);
+
+ if (dev->mtd) {
+ if (dev->tr->release)
+ dev->tr->release(dev);
+ __put_mtd_device(dev->mtd);
+ }
+unlock:
+ mutex_unlock(&mtd_table_mutex);
+ mutex_unlock(&dev->lock);
+ blktrans_dev_put(dev);
+}
+
+static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
+{
+ struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
+ int ret = -ENXIO;
+
+ if (!dev)
+ return ret;
+
+ mutex_lock(&dev->lock);
+
+ if (!dev->mtd)
+ goto unlock;
+
+ ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
+unlock:
+ mutex_unlock(&dev->lock);
+ blktrans_dev_put(dev);
+ return ret;
+}
+
+static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
+ unsigned int cmd, unsigned long arg)
+{
+ struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
+ int ret = -ENXIO;
+
+ if (!dev)
+ return ret;
+
+ mutex_lock(&dev->lock);
+
+ if (!dev->mtd)
+ goto unlock;
+
+ switch (cmd) {
+ case BLKFLSBUF:
+ ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
+ break;
+ default:
+ ret = -ENOTTY;
+ }
+unlock:
+ mutex_unlock(&dev->lock);
+ blktrans_dev_put(dev);
+ return ret;
+}
+
+static const struct block_device_operations mtd_block_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 mtd_blktrans_dev *d;
+ int last_devnum = -1;
+ struct gendisk *gd;
+ int ret;
+
+ if (mutex_trylock(&mtd_table_mutex)) {
+ mutex_unlock(&mtd_table_mutex);
+ BUG();
+ }
+
+ mutex_lock(&blktrans_ref_mutex);
+ 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 */
+ mutex_unlock(&blktrans_ref_mutex);
+ 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;
+ }
+
+ ret = -EBUSY;
+ if (new->devnum == -1)
+ new->devnum = last_devnum+1;
+
+ /* Check that the device and any partitions will get valid
+ * minor numbers and that the disk naming code below can cope
+ * with this number. */
+ if (new->devnum > (MINORMASK >> tr->part_bits) ||
+ (tr->part_bits && new->devnum >= 27 * 26)) {
+ mutex_unlock(&blktrans_ref_mutex);
+ goto error1;
+ }
+
+ list_add_tail(&new->list, &tr->devs);
+ added:
+ mutex_unlock(&blktrans_ref_mutex);
+
+ mutex_init(&new->lock);
+ kref_init(&new->ref);
+ if (!tr->writesect)
+ new->readonly = 1;
+
+ /* Create gendisk */
+ ret = -ENOMEM;
+ gd = alloc_disk(1 << tr->part_bits);
+
+ if (!gd)
+ goto error2;
+
+ new->disk = gd;
+ gd->private_data = new;
+ gd->major = tr->major;
+ gd->first_minor = (new->devnum) << tr->part_bits;
+ gd->fops = &mtd_block_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);
+
+ set_capacity(gd, (new->size * tr->blksize) >> 9);
+
+ /* Create the request queue */
+ spin_lock_init(&new->queue_lock);
+ new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
+
+ if (!new->rq)
+ goto error3;
+
+ if (tr->flush)
+ blk_queue_flush(new->rq, REQ_FLUSH);
+
+ new->rq->queuedata = new;
+ blk_queue_logical_block_size(new->rq, tr->blksize);
+
+ queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq);
+ queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, new->rq);
+
+ if (tr->discard) {
+ queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
+ new->rq->limits.max_discard_sectors = UINT_MAX;
+ }
+
+ gd->queue = new->rq;
+
+ /* Create processing workqueue */
+ new->wq = alloc_workqueue("%s%d", 0, 0,
+ tr->name, new->mtd->index);
+ if (!new->wq)
+ goto error4;
+ INIT_WORK(&new->work, mtd_blktrans_work);
+
+ gd->driverfs_dev = &new->mtd->dev;
+
+ if (new->readonly)
+ set_disk_ro(gd, 1);
+
+ add_disk(gd);
+
+ if (new->disk_attributes) {
+ ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
+ new->disk_attributes);
+ WARN_ON(ret);
+ }
+ return 0;
+error4:
+ blk_cleanup_queue(new->rq);
+error3:
+ put_disk(new->disk);
+error2:
+ list_del(&new->list);
+error1:
+ return ret;
+}
+
+int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
+{
+ unsigned long flags;
+
+ if (mutex_trylock(&mtd_table_mutex)) {
+ mutex_unlock(&mtd_table_mutex);
+ BUG();
+ }
+
+ if (old->disk_attributes)
+ sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
+ old->disk_attributes);
+
+ /* Stop new requests to arrive */
+ del_gendisk(old->disk);
+
+ /* Stop workqueue. This will perform any pending request. */
+ destroy_workqueue(old->wq);
+
+ /* Kill current requests */
+ spin_lock_irqsave(&old->queue_lock, flags);
+ old->rq->queuedata = NULL;
+ blk_start_queue(old->rq);
+ spin_unlock_irqrestore(&old->queue_lock, flags);
+
+ /* If the device is currently open, tell trans driver to close it,
+ then put mtd device, and don't touch it again */
+ mutex_lock(&old->lock);
+ if (old->open) {
+ if (old->tr->release)
+ old->tr->release(old);
+ __put_mtd_device(old->mtd);
+ }
+
+ old->mtd = NULL;
+
+ mutex_unlock(&old->lock);
+ blktrans_dev_put(old);
+ 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)
+{
+ struct mtd_info *mtd;
+ int ret;
+
+ /* 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);
+
+
+ mutex_lock(&mtd_table_mutex);
+
+ ret = register_blkdev(tr->major, tr->name);
+ if (ret < 0) {
+ printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
+ tr->name, tr->major, ret);
+ mutex_unlock(&mtd_table_mutex);
+ return ret;
+ }
+
+ if (ret)
+ tr->major = ret;
+
+ tr->blkshift = ffs(tr->blksize) - 1;
+
+ INIT_LIST_HEAD(&tr->devs);
+ list_add(&tr->list, &blktrans_majors);
+
+ mtd_for_each_device(mtd)
+ if (mtd->type != MTD_ABSENT)
+ tr->add_mtd(tr, mtd);
+
+ 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);
+
+ /* 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);
+
+ unregister_blkdev(tr->major, tr->name);
+ mutex_unlock(&mtd_table_mutex);
+
+ 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'");
Code Review / kvmfornfv.git / blobdiff