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Diffstat (limited to 'drivers/mtd/mtd_blkdevs.c')
-rw-r--r--drivers/mtd/mtd_blkdevs.c548
1 files changed, 548 insertions, 0 deletions
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
new file mode 100644
index 0000000000..5bc32108ca
--- /dev/null
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -0,0 +1,548 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Interface to Linux block layer for MTD 'translation layers'.
+ *
+ * Copyright © 2003-2010 David Woodhouse <dwmw2@infradead.org>
+ */
+
+#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/blk-mq.h>
+#include <linux/blkpg.h>
+#include <linux/spinlock.h>
+#include <linux/hdreg.h>
+#include <linux/mutex.h>
+#include <linux/uaccess.h>
+
+#include "mtdcore.h"
+
+static LIST_HEAD(blktrans_majors);
+
+static void blktrans_dev_release(struct kref *kref)
+{
+ struct mtd_blktrans_dev *dev =
+ container_of(kref, struct mtd_blktrans_dev, ref);
+
+ put_disk(dev->disk);
+ blk_mq_free_tag_set(dev->tag_set);
+ kfree(dev->tag_set);
+ list_del(&dev->list);
+ kfree(dev);
+}
+
+static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
+{
+ kref_put(&dev->ref, blktrans_dev_release);
+}
+
+
+static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr,
+ struct mtd_blktrans_dev *dev,
+ struct request *req)
+{
+ struct req_iterator iter;
+ struct bio_vec bvec;
+ unsigned long block, nsect;
+ char *buf;
+
+ block = blk_rq_pos(req) << 9 >> tr->blkshift;
+ nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
+
+ switch (req_op(req)) {
+ case REQ_OP_FLUSH:
+ if (tr->flush(dev))
+ return BLK_STS_IOERR;
+ return BLK_STS_OK;
+ case REQ_OP_DISCARD:
+ if (tr->discard(dev, block, nsect))
+ return BLK_STS_IOERR;
+ return BLK_STS_OK;
+ case REQ_OP_READ:
+ buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
+ for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
+ if (tr->readsect(dev, block, buf)) {
+ kunmap(bio_page(req->bio));
+ return BLK_STS_IOERR;
+ }
+ }
+ kunmap(bio_page(req->bio));
+
+ rq_for_each_segment(bvec, req, iter)
+ flush_dcache_page(bvec.bv_page);
+ return BLK_STS_OK;
+ case REQ_OP_WRITE:
+ if (!tr->writesect)
+ return BLK_STS_IOERR;
+
+ rq_for_each_segment(bvec, req, iter)
+ flush_dcache_page(bvec.bv_page);
+
+ buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
+ for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
+ if (tr->writesect(dev, block, buf)) {
+ kunmap(bio_page(req->bio));
+ return BLK_STS_IOERR;
+ }
+ }
+ kunmap(bio_page(req->bio));
+ return BLK_STS_OK;
+ default:
+ return BLK_STS_IOERR;
+ }
+}
+
+int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
+{
+ return dev->bg_stop;
+}
+EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
+
+static struct request *mtd_next_request(struct mtd_blktrans_dev *dev)
+{
+ struct request *rq;
+
+ rq = list_first_entry_or_null(&dev->rq_list, struct request, queuelist);
+ if (rq) {
+ list_del_init(&rq->queuelist);
+ blk_mq_start_request(rq);
+ return rq;
+ }
+
+ return NULL;
+}
+
+static void mtd_blktrans_work(struct mtd_blktrans_dev *dev)
+ __releases(&dev->queue_lock)
+ __acquires(&dev->queue_lock)
+{
+ struct mtd_blktrans_ops *tr = dev->tr;
+ struct request *req = NULL;
+ int background_done = 0;
+
+ while (1) {
+ blk_status_t res;
+
+ dev->bg_stop = false;
+ if (!req && !(req = mtd_next_request(dev))) {
+ if (tr->background && !background_done) {
+ spin_unlock_irq(&dev->queue_lock);
+ mutex_lock(&dev->lock);
+ tr->background(dev);
+ mutex_unlock(&dev->lock);
+ spin_lock_irq(&dev->queue_lock);
+ /*
+ * Do background processing just once per idle
+ * period.
+ */
+ background_done = !dev->bg_stop;
+ continue;
+ }
+ break;
+ }
+
+ spin_unlock_irq(&dev->queue_lock);
+
+ mutex_lock(&dev->lock);
+ res = do_blktrans_request(dev->tr, dev, req);
+ mutex_unlock(&dev->lock);
+
+ if (!blk_update_request(req, res, blk_rq_cur_bytes(req))) {
+ __blk_mq_end_request(req, res);
+ req = NULL;
+ }
+
+ background_done = 0;
+ cond_resched();
+ spin_lock_irq(&dev->queue_lock);
+ }
+}
+
+static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx,
+ const struct blk_mq_queue_data *bd)
+{
+ struct mtd_blktrans_dev *dev;
+
+ dev = hctx->queue->queuedata;
+ if (!dev) {
+ blk_mq_start_request(bd->rq);
+ return BLK_STS_IOERR;
+ }
+
+ spin_lock_irq(&dev->queue_lock);
+ list_add_tail(&bd->rq->queuelist, &dev->rq_list);
+ mtd_blktrans_work(dev);
+ spin_unlock_irq(&dev->queue_lock);
+
+ return BLK_STS_OK;
+}
+
+static int blktrans_open(struct gendisk *disk, blk_mode_t mode)
+{
+ struct mtd_blktrans_dev *dev = disk->private_data;
+ int ret = 0;
+
+ kref_get(&dev->ref);
+
+ mutex_lock(&dev->lock);
+
+ if (dev->open)
+ goto unlock;
+
+ __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->writable = mode & BLK_OPEN_WRITE;
+
+unlock:
+ dev->open++;
+ mutex_unlock(&dev->lock);
+ return ret;
+
+error_release:
+ if (dev->tr->release)
+ dev->tr->release(dev);
+error_put:
+ module_put(dev->tr->owner);
+ mutex_unlock(&dev->lock);
+ blktrans_dev_put(dev);
+ return ret;
+}
+
+static void blktrans_release(struct gendisk *disk)
+{
+ struct mtd_blktrans_dev *dev = disk->private_data;
+
+ mutex_lock(&dev->lock);
+
+ if (--dev->open)
+ goto unlock;
+
+ module_put(dev->tr->owner);
+
+ if (dev->mtd) {
+ if (dev->tr->release)
+ dev->tr->release(dev);
+ __put_mtd_device(dev->mtd);
+ }
+unlock:
+ 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 = bdev->bd_disk->private_data;
+ int ret = -ENXIO;
+
+ mutex_lock(&dev->lock);
+
+ if (!dev->mtd)
+ goto unlock;
+
+ ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY;
+unlock:
+ mutex_unlock(&dev->lock);
+ return ret;
+}
+
+static const struct block_device_operations mtd_block_ops = {
+ .owner = THIS_MODULE,
+ .open = blktrans_open,
+ .release = blktrans_release,
+ .getgeo = blktrans_getgeo,
+};
+
+static const struct blk_mq_ops mtd_mq_ops = {
+ .queue_rq = mtd_queue_rq,
+};
+
+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;
+
+ lockdep_assert_held(&mtd_table_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 */
+ 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))
+ return ret;
+
+ list_add_tail(&new->list, &tr->devs);
+ added:
+
+ mutex_init(&new->lock);
+ kref_init(&new->ref);
+ if (!tr->writesect)
+ new->readonly = 1;
+
+ ret = -ENOMEM;
+ new->tag_set = kzalloc(sizeof(*new->tag_set), GFP_KERNEL);
+ if (!new->tag_set)
+ goto out_list_del;
+
+ ret = blk_mq_alloc_sq_tag_set(new->tag_set, &mtd_mq_ops, 2,
+ BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING);
+ if (ret)
+ goto out_kfree_tag_set;
+
+ /* Create gendisk */
+ gd = blk_mq_alloc_disk(new->tag_set, new);
+ if (IS_ERR(gd)) {
+ ret = PTR_ERR(gd);
+ goto out_free_tag_set;
+ }
+
+ new->disk = gd;
+ new->rq = new->disk->queue;
+ gd->private_data = new;
+ gd->major = tr->major;
+ gd->first_minor = (new->devnum) << tr->part_bits;
+ gd->minors = 1 << 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);
+ gd->flags |= GENHD_FL_NO_PART;
+ }
+
+ set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
+
+ /* Create the request queue */
+ spin_lock_init(&new->queue_lock);
+ INIT_LIST_HEAD(&new->rq_list);
+
+ if (tr->flush)
+ blk_queue_write_cache(new->rq, true, false);
+
+ blk_queue_logical_block_size(new->rq, tr->blksize);
+
+ blk_queue_flag_set(QUEUE_FLAG_NONROT, new->rq);
+ blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, new->rq);
+
+ if (tr->discard) {
+ blk_queue_max_discard_sectors(new->rq, UINT_MAX);
+ new->rq->limits.discard_granularity = tr->blksize;
+ }
+
+ gd->queue = new->rq;
+
+ if (new->readonly)
+ set_disk_ro(gd, 1);
+
+ ret = device_add_disk(&new->mtd->dev, gd, NULL);
+ if (ret)
+ goto out_cleanup_disk;
+
+ if (new->disk_attributes) {
+ ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
+ new->disk_attributes);
+ WARN_ON(ret);
+ }
+ return 0;
+
+out_cleanup_disk:
+ put_disk(new->disk);
+out_free_tag_set:
+ blk_mq_free_tag_set(new->tag_set);
+out_kfree_tag_set:
+ kfree(new->tag_set);
+out_list_del:
+ list_del(&new->list);
+ return ret;
+}
+
+int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
+{
+ unsigned long flags;
+
+ lockdep_assert_held(&mtd_table_mutex);
+
+ 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);
+
+ /* Kill current requests */
+ spin_lock_irqsave(&old->queue_lock, flags);
+ old->rq->queuedata = NULL;
+ spin_unlock_irqrestore(&old->queue_lock, flags);
+
+ /* freeze+quiesce queue to ensure all requests are flushed */
+ blk_mq_freeze_queue(old->rq);
+ blk_mq_quiesce_queue(old->rq);
+ blk_mq_unquiesce_queue(old->rq);
+ blk_mq_unfreeze_queue(old->rq);
+
+ /* 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 || mtd->type == MTD_UBIVOLUME)
+ 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);
+
+ 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);
+ return ret;
+ }
+
+ if (ret)
+ tr->major = ret;
+
+ tr->blkshift = ffs(tr->blksize) - 1;
+
+ INIT_LIST_HEAD(&tr->devs);
+
+ mutex_lock(&mtd_table_mutex);
+ list_add(&tr->list, &blktrans_majors);
+ mtd_for_each_device(mtd)
+ if (mtd->type != MTD_ABSENT && mtd->type != MTD_UBIVOLUME)
+ 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);
+
+ mutex_unlock(&mtd_table_mutex);
+ unregister_blkdev(tr->major, tr->name);
+
+ 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'");