| /* |
| * 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/init.h> |
| #include <linux/mutex.h> |
| #include <linux/kthread.h> |
| #include <asm/uaccess.h> |
| |
| #include "mtdcore.h" |
| |
| static LIST_HEAD(blktrans_majors); |
| static DEFINE_MUTEX(blktrans_ref_mutex); |
| |
| 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; |
| } |
| |
| 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 = req->buffer; |
| |
| if (!blk_fs_request(req)) |
| return -EIO; |
| |
| if (blk_rq_pos(req) + blk_rq_cur_sectors(req) > |
| get_capacity(req->rq_disk)) |
| return -EIO; |
| |
| if (blk_discard_rq(req)) |
| 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; |
| } |
| } |
| |
| static int mtd_blktrans_thread(void *arg) |
| { |
| struct mtd_blktrans_dev *dev = arg; |
| struct request_queue *rq = dev->rq; |
| struct request *req = NULL; |
| |
| spin_lock_irq(rq->queue_lock); |
| |
| while (!kthread_should_stop()) { |
| int res; |
| |
| if (!req && !(req = blk_fetch_request(rq))) { |
| set_current_state(TASK_INTERRUPTIBLE); |
| spin_unlock_irq(rq->queue_lock); |
| schedule(); |
| spin_lock_irq(rq->queue_lock); |
| continue; |
| } |
| |
| 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; |
| } |
| |
| if (req) |
| __blk_end_request_all(req, -EIO); |
| |
| spin_unlock_irq(rq->queue_lock); |
| |
| return 0; |
| } |
| |
| 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 |
| wake_up_process(dev->thread); |
| } |
| |
| static int blktrans_open(struct block_device *bdev, fmode_t mode) |
| { |
| struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); |
| int ret; |
| |
| if (!dev) |
| return -ERESTARTSYS; |
| |
| mutex_lock(&dev->lock); |
| |
| if (!dev->mtd) { |
| ret = -ENXIO; |
| goto unlock; |
| } |
| |
| ret = !dev->open++ && dev->tr->open ? dev->tr->open(dev) : 0; |
| |
| /* Take another reference on the device so it won't go away till |
| last release */ |
| if (!ret) |
| kref_get(&dev->ref); |
| unlock: |
| mutex_unlock(&dev->lock); |
| blktrans_dev_put(dev); |
| return ret; |
| } |
| |
| static int blktrans_release(struct gendisk *disk, fmode_t mode) |
| { |
| struct mtd_blktrans_dev *dev = blktrans_dev_get(disk); |
| int ret = -ENXIO; |
| |
| if (!dev) |
| return ret; |
| |
| mutex_lock(&dev->lock); |
| |
| /* Release one reference, we sure its not the last one here*/ |
| kref_put(&dev->ref, blktrans_dev_release); |
| |
| if (!dev->mtd) |
| goto unlock; |
| |
| ret = !--dev->open && dev->tr->release ? dev->tr->release(dev) : 0; |
| unlock: |
| mutex_unlock(&dev->lock); |
| blktrans_dev_put(dev); |
| return ret; |
| } |
| |
| 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_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; |
| 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_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); |
| |
| 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; |
| |
| new->rq->queuedata = new; |
| blk_queue_logical_block_size(new->rq, tr->blksize); |
| |
| if (tr->discard) |
| queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, |
| new->rq); |
| |
| gd->queue = new->rq; |
| |
| __get_mtd_device(new->mtd); |
| __module_get(tr->owner); |
| |
| /* Create processing thread */ |
| /* TODO: workqueue ? */ |
| new->thread = kthread_run(mtd_blktrans_thread, new, |
| "%s%d", tr->name, new->mtd->index); |
| if (IS_ERR(new->thread)) { |
| ret = PTR_ERR(new->thread); |
| goto error4; |
| } |
| 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: |
| module_put(tr->owner); |
| __put_mtd_device(new->mtd); |
| blk_cleanup_queue(new->rq); |
| error3: |
| put_disk(new->disk); |
| error2: |
| list_del(&new->list); |
| error1: |
| kfree(new); |
| 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 the thread */ |
| kthread_stop(old->thread); |
| |
| /* 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); |
| |
| /* Ask trans driver for release to the mtd device */ |
| mutex_lock(&old->lock); |
| if (old->open && old->tr->release) { |
| old->tr->release(old); |
| old->open = 0; |
| } |
| |
| __put_mtd_device(old->mtd); |
| module_put(old->tr->owner); |
| |
| /* At that point, we don't touch the mtd anymore */ |
| 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) { |
| 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; |
| } |
| |
| 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'"); |