1 files changed, 669 insertions, 0 deletions

diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
new file mode 100644
index 000000000..c9eb78f10
--- /dev/null
+++ b/drivers/mtd/ubi/block.c
@@ -0,0 +1,669 @@
+/*
+ * Copyright (c) 2014 Ezequiel Garcia
+ * Copyright (c) 2011 Free Electrons
+ *
+ * Driver parameter handling strongly based on drivers/mtd/ubi/build.c
+ *   Copyright (c) International Business Machines Corp., 2006
+ *   Copyright (c) Nokia Corporation, 2007
+ *   Authors: Artem Bityutskiy, Frank Haverkamp
+ *
+ * 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, version 2.
+ *
+ * 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.
+ */
+
+/*
+ * Read-only block devices on top of UBI volumes
+ *
+ * A simple implementation to allow a block device to be layered on top of a
+ * UBI volume. The implementation is provided by creating a static 1-to-1
+ * mapping between the block device and the UBI volume.
+ *
+ * The addressed byte is obtained from the addressed block sector, which is
+ * mapped linearly into the corresponding LEB:
+ *
+ *   LEB number = addressed byte / LEB size
+ *
+ * This feature is compiled in the UBI core, and adds a 'block' parameter
+ * to allow early creation of block devices on top of UBI volumes. Runtime
+ * block creation/removal for UBI volumes is provided through two UBI ioctls:
+ * UBI_IOCVOLCRBLK and UBI_IOCVOLRMBLK.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/mtd/ubi.h>
+#include <linux/workqueue.h>
+#include <linux/blkdev.h>
+#include <linux/blk-mq.h>
+#include <linux/hdreg.h>
+#include <linux/scatterlist.h>
+#include <asm/div64.h>
+
+#include "ubi-media.h"
+#include "ubi.h"
+
+/* Maximum number of supported devices */
+#define UBIBLOCK_MAX_DEVICES 32
+
+/* Maximum length of the 'block=' parameter */
+#define UBIBLOCK_PARAM_LEN 63
+
+/* Maximum number of comma-separated items in the 'block=' parameter */
+#define UBIBLOCK_PARAM_COUNT 2
+
+struct ubiblock_param {
+	int ubi_num;
+	int vol_id;
+	char name[UBIBLOCK_PARAM_LEN+1];
+};
+
+struct ubiblock_pdu {
+	struct work_struct work;
+	struct ubi_sgl usgl;
+};
+
+/* Numbers of elements set in the @ubiblock_param array */
+static int ubiblock_devs __initdata;
+
+/* MTD devices specification parameters */
+static struct ubiblock_param ubiblock_param[UBIBLOCK_MAX_DEVICES] __initdata;
+
+struct ubiblock {
+	struct ubi_volume_desc *desc;
+	int ubi_num;
+	int vol_id;
+	int refcnt;
+	int leb_size;
+
+	struct gendisk *gd;
+	struct request_queue *rq;
+
+	struct workqueue_struct *wq;
+
+	struct mutex dev_mutex;
+	struct list_head list;
+	struct blk_mq_tag_set tag_set;
+};
+
+/* Linked list of all ubiblock instances */
+static LIST_HEAD(ubiblock_devices);
+static DEFINE_MUTEX(devices_mutex);
+static int ubiblock_major;
+
+static int __init ubiblock_set_param(const char *val,
+				     const struct kernel_param *kp)
+{
+	int i, ret;
+	size_t len;
+	struct ubiblock_param *param;
+	char buf[UBIBLOCK_PARAM_LEN];
+	char *pbuf = &buf[0];
+	char *tokens[UBIBLOCK_PARAM_COUNT];
+
+	if (!val)
+		return -EINVAL;
+
+	len = strnlen(val, UBIBLOCK_PARAM_LEN);
+	if (len == 0) {
+		pr_warn("UBI: block: empty 'block=' parameter - ignored\n");
+		return 0;
+	}
+
+	if (len == UBIBLOCK_PARAM_LEN) {
+		pr_err("UBI: block: parameter \"%s\" is too long, max. is %d\n",
+		       val, UBIBLOCK_PARAM_LEN);
+		return -EINVAL;
+	}
+
+	strcpy(buf, val);
+
+	/* Get rid of the final newline */
+	if (buf[len - 1] == '\n')
+		buf[len - 1] = '\0';
+
+	for (i = 0; i < UBIBLOCK_PARAM_COUNT; i++)
+		tokens[i] = strsep(&pbuf, ",");
+
+	param = &ubiblock_param[ubiblock_devs];
+	if (tokens[1]) {
+		/* Two parameters: can be 'ubi, vol_id' or 'ubi, vol_name' */
+		ret = kstrtoint(tokens[0], 10, &param->ubi_num);
+		if (ret < 0)
+			return -EINVAL;
+
+		/* Second param can be a number or a name */
+		ret = kstrtoint(tokens[1], 10, &param->vol_id);
+		if (ret < 0) {
+			param->vol_id = -1;
+			strcpy(param->name, tokens[1]);
+		}
+
+	} else {
+		/* One parameter: must be device path */
+		strcpy(param->name, tokens[0]);
+		param->ubi_num = -1;
+		param->vol_id = -1;
+	}
+
+	ubiblock_devs++;
+
+	return 0;
+}
+
+static struct kernel_param_ops ubiblock_param_ops = {
+	.set    = ubiblock_set_param,
+};
+module_param_cb(block, &ubiblock_param_ops, NULL, 0);
+MODULE_PARM_DESC(block, "Attach block devices to UBI volumes. Parameter format: block=<path|dev,num|dev,name>.\n"
+			"Multiple \"block\" parameters may be specified.\n"
+			"UBI volumes may be specified by their number, name, or path to the device node.\n"
+			"Examples\n"
+			"Using the UBI volume path:\n"
+			"ubi.block=/dev/ubi0_0\n"
+			"Using the UBI device, and the volume name:\n"
+			"ubi.block=0,rootfs\n"
+			"Using both UBI device number and UBI volume number:\n"
+			"ubi.block=0,0\n");
+
+static struct ubiblock *find_dev_nolock(int ubi_num, int vol_id)
+{
+	struct ubiblock *dev;
+
+	list_for_each_entry(dev, &ubiblock_devices, list)
+		if (dev->ubi_num == ubi_num && dev->vol_id == vol_id)
+			return dev;
+	return NULL;
+}
+
+static int ubiblock_read(struct ubiblock_pdu *pdu)
+{
+	int ret, leb, offset, bytes_left, to_read;
+	u64 pos;
+	struct request *req = blk_mq_rq_from_pdu(pdu);
+	struct ubiblock *dev = req->q->queuedata;
+
+	to_read = blk_rq_bytes(req);
+	pos = blk_rq_pos(req) << 9;
+
+	/* Get LEB:offset address to read from */
+	offset = do_div(pos, dev->leb_size);
+	leb = pos;
+	bytes_left = to_read;
+
+	while (bytes_left) {
+		/*
+		 * We can only read one LEB at a time. Therefore if the read
+		 * length is larger than one LEB size, we split the operation.
+		 */
+		if (offset + to_read > dev->leb_size)
+			to_read = dev->leb_size - offset;
+
+		ret = ubi_read_sg(dev->desc, leb, &pdu->usgl, offset, to_read);
+		if (ret < 0)
+			return ret;
+
+		bytes_left -= to_read;
+		to_read = bytes_left;
+		leb += 1;
+		offset = 0;
+	}
+	return 0;
+}
+
+static int ubiblock_open(struct block_device *bdev, fmode_t mode)
+{
+	struct ubiblock *dev = bdev->bd_disk->private_data;
+	int ret;
+
+	mutex_lock(&dev->dev_mutex);
+	if (dev->refcnt > 0) {
+		/*
+		 * The volume is already open, just increase the reference
+		 * counter.
+		 */
+		goto out_done;
+	}
+
+	/*
+	 * We want users to be aware they should only mount us as read-only.
+	 * It's just a paranoid check, as write requests will get rejected
+	 * in any case.
+	 */
+	if (mode & FMODE_WRITE) {
+		ret = -EPERM;
+		goto out_unlock;
+	}
+
+	dev->desc = ubi_open_volume(dev->ubi_num, dev->vol_id, UBI_READONLY);
+	if (IS_ERR(dev->desc)) {
+		dev_err(disk_to_dev(dev->gd), "failed to open ubi volume %d_%d",
+			dev->ubi_num, dev->vol_id);
+		ret = PTR_ERR(dev->desc);
+		dev->desc = NULL;
+		goto out_unlock;
+	}
+
+out_done:
+	dev->refcnt++;
+	mutex_unlock(&dev->dev_mutex);
+	return 0;
+
+out_unlock:
+	mutex_unlock(&dev->dev_mutex);
+	return ret;
+}
+
+static void ubiblock_release(struct gendisk *gd, fmode_t mode)
+{
+	struct ubiblock *dev = gd->private_data;
+
+	mutex_lock(&dev->dev_mutex);
+	dev->refcnt--;
+	if (dev->refcnt == 0) {
+		ubi_close_volume(dev->desc);
+		dev->desc = NULL;
+	}
+	mutex_unlock(&dev->dev_mutex);
+}
+
+static int ubiblock_getgeo(struct block_device *bdev, struct hd_geometry *geo)
+{
+	/* Some tools might require this information */
+	geo->heads = 1;
+	geo->cylinders = 1;
+	geo->sectors = get_capacity(bdev->bd_disk);
+	geo->start = 0;
+	return 0;
+}
+
+static const struct block_device_operations ubiblock_ops = {
+	.owner = THIS_MODULE,
+	.open = ubiblock_open,
+	.release = ubiblock_release,
+	.getgeo	= ubiblock_getgeo,
+};
+
+static void ubiblock_do_work(struct work_struct *work)
+{
+	int ret;
+	struct ubiblock_pdu *pdu = container_of(work, struct ubiblock_pdu, work);
+	struct request *req = blk_mq_rq_from_pdu(pdu);
+
+	blk_mq_start_request(req);
+
+	/*
+	 * It is safe to ignore the return value of blk_rq_map_sg() because
+	 * the number of sg entries is limited to UBI_MAX_SG_COUNT
+	 * and ubi_read_sg() will check that limit.
+	 */
+	blk_rq_map_sg(req->q, req, pdu->usgl.sg);
+
+	ret = ubiblock_read(pdu);
+	rq_flush_dcache_pages(req);
+
+	blk_mq_end_request(req, ret);
+}
+
+static int ubiblock_queue_rq(struct blk_mq_hw_ctx *hctx,
+			     const struct blk_mq_queue_data *bd)
+{
+	struct request *req = bd->rq;
+	struct ubiblock *dev = hctx->queue->queuedata;
+	struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
+
+	if (req->cmd_type != REQ_TYPE_FS)
+		return BLK_MQ_RQ_QUEUE_ERROR;
+
+	if (rq_data_dir(req) != READ)
+		return BLK_MQ_RQ_QUEUE_ERROR; /* Write not implemented */
+
+	ubi_sgl_init(&pdu->usgl);
+	queue_work(dev->wq, &pdu->work);
+
+	return BLK_MQ_RQ_QUEUE_OK;
+}
+
+static int ubiblock_init_request(void *data, struct request *req,
+				 unsigned int hctx_idx,
+				 unsigned int request_idx,
+				 unsigned int numa_node)
+{
+	struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
+
+	sg_init_table(pdu->usgl.sg, UBI_MAX_SG_COUNT);
+	INIT_WORK(&pdu->work, ubiblock_do_work);
+
+	return 0;
+}
+
+static struct blk_mq_ops ubiblock_mq_ops = {
+	.queue_rq       = ubiblock_queue_rq,
+	.init_request	= ubiblock_init_request,
+	.map_queue      = blk_mq_map_queue,
+};
+
+int ubiblock_create(struct ubi_volume_info *vi)
+{
+	struct ubiblock *dev;
+	struct gendisk *gd;
+	u64 disk_capacity = vi->used_bytes >> 9;
+	int ret;
+
+	if ((sector_t)disk_capacity != disk_capacity)
+		return -EFBIG;
+	/* Check that the volume isn't already handled */
+	mutex_lock(&devices_mutex);
+	if (find_dev_nolock(vi->ubi_num, vi->vol_id)) {
+		mutex_unlock(&devices_mutex);
+		return -EEXIST;
+	}
+	mutex_unlock(&devices_mutex);
+
+	dev = kzalloc(sizeof(struct ubiblock), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	mutex_init(&dev->dev_mutex);
+
+	dev->ubi_num = vi->ubi_num;
+	dev->vol_id = vi->vol_id;
+	dev->leb_size = vi->usable_leb_size;
+
+	/* Initialize the gendisk of this ubiblock device */
+	gd = alloc_disk(1);
+	if (!gd) {
+		pr_err("UBI: block: alloc_disk failed");
+		ret = -ENODEV;
+		goto out_free_dev;
+	}
+
+	gd->fops = &ubiblock_ops;
+	gd->major = ubiblock_major;
+	gd->first_minor = dev->ubi_num * UBI_MAX_VOLUMES + dev->vol_id;
+	gd->private_data = dev;
+	sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
+	set_capacity(gd, disk_capacity);
+	dev->gd = gd;
+
+	dev->tag_set.ops = &ubiblock_mq_ops;
+	dev->tag_set.queue_depth = 64;
+	dev->tag_set.numa_node = NUMA_NO_NODE;
+	dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
+	dev->tag_set.cmd_size = sizeof(struct ubiblock_pdu);
+	dev->tag_set.driver_data = dev;
+	dev->tag_set.nr_hw_queues = 1;
+
+	ret = blk_mq_alloc_tag_set(&dev->tag_set);
+	if (ret) {
+		dev_err(disk_to_dev(dev->gd), "blk_mq_alloc_tag_set failed");
+		goto out_put_disk;
+	}
+
+	dev->rq = blk_mq_init_queue(&dev->tag_set);
+	if (IS_ERR(dev->rq)) {
+		dev_err(disk_to_dev(gd), "blk_mq_init_queue failed");
+		ret = PTR_ERR(dev->rq);
+		goto out_free_tags;
+	}
+	blk_queue_max_segments(dev->rq, UBI_MAX_SG_COUNT);
+
+	dev->rq->queuedata = dev;
+	dev->gd->queue = dev->rq;
+
+	/*
+	 * Create one workqueue per volume (per registered block device).
+	 * Rembember workqueues are cheap, they're not threads.
+	 */
+	dev->wq = alloc_workqueue("%s", 0, 0, gd->disk_name);
+	if (!dev->wq) {
+		ret = -ENOMEM;
+		goto out_free_queue;
+	}
+
+	mutex_lock(&devices_mutex);
+	list_add_tail(&dev->list, &ubiblock_devices);
+	mutex_unlock(&devices_mutex);
+
+	/* Must be the last step: anyone can call file ops from now on */
+	add_disk(dev->gd);
+	dev_info(disk_to_dev(dev->gd), "created from ubi%d:%d(%s)",
+		 dev->ubi_num, dev->vol_id, vi->name);
+	return 0;
+
+out_free_queue:
+	blk_cleanup_queue(dev->rq);
+out_free_tags:
+	blk_mq_free_tag_set(&dev->tag_set);
+out_put_disk:
+	put_disk(dev->gd);
+out_free_dev:
+	kfree(dev);
+
+	return ret;
+}
+
+static void ubiblock_cleanup(struct ubiblock *dev)
+{
+	/* Stop new requests to arrive */
+	del_gendisk(dev->gd);
+	/* Flush pending work */
+	destroy_workqueue(dev->wq);
+	/* Finally destroy the blk queue */
+	blk_cleanup_queue(dev->rq);
+	blk_mq_free_tag_set(&dev->tag_set);
+	dev_info(disk_to_dev(dev->gd), "released");
+	put_disk(dev->gd);
+}
+
+int ubiblock_remove(struct ubi_volume_info *vi)
+{
+	struct ubiblock *dev;
+
+	mutex_lock(&devices_mutex);
+	dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
+	if (!dev) {
+		mutex_unlock(&devices_mutex);
+		return -ENODEV;
+	}
+
+	/* Found a device, let's lock it so we can check if it's busy */
+	mutex_lock(&dev->dev_mutex);
+	if (dev->refcnt > 0) {
+		mutex_unlock(&dev->dev_mutex);
+		mutex_unlock(&devices_mutex);
+		return -EBUSY;
+	}
+
+	/* Remove from device list */
+	list_del(&dev->list);
+	mutex_unlock(&devices_mutex);
+
+	ubiblock_cleanup(dev);
+	mutex_unlock(&dev->dev_mutex);
+	kfree(dev);
+	return 0;
+}
+
+static int ubiblock_resize(struct ubi_volume_info *vi)
+{
+	struct ubiblock *dev;
+	u64 disk_capacity = vi->used_bytes >> 9;
+
+	/*
+	 * Need to lock the device list until we stop using the device,
+	 * otherwise the device struct might get released in
+	 * 'ubiblock_remove()'.
+	 */
+	mutex_lock(&devices_mutex);
+	dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
+	if (!dev) {
+		mutex_unlock(&devices_mutex);
+		return -ENODEV;
+	}
+	if ((sector_t)disk_capacity != disk_capacity) {
+		mutex_unlock(&devices_mutex);
+		dev_warn(disk_to_dev(dev->gd), "the volume is too big (%d LEBs), cannot resize",
+			 vi->size);
+		return -EFBIG;
+	}
+
+	mutex_lock(&dev->dev_mutex);
+
+	if (get_capacity(dev->gd) != disk_capacity) {
+		set_capacity(dev->gd, disk_capacity);
+		dev_info(disk_to_dev(dev->gd), "resized to %lld bytes",
+			 vi->used_bytes);
+	}
+	mutex_unlock(&dev->dev_mutex);
+	mutex_unlock(&devices_mutex);
+	return 0;
+}
+
+static int ubiblock_notify(struct notifier_block *nb,
+			 unsigned long notification_type, void *ns_ptr)
+{
+	struct ubi_notification *nt = ns_ptr;
+
+	switch (notification_type) {
+	case UBI_VOLUME_ADDED:
+		/*
+		 * We want to enforce explicit block device creation for
+		 * volumes, so when a volume is added we do nothing.
+		 */
+		break;
+	case UBI_VOLUME_REMOVED:
+		ubiblock_remove(&nt->vi);
+		break;
+	case UBI_VOLUME_RESIZED:
+		ubiblock_resize(&nt->vi);
+		break;
+	case UBI_VOLUME_UPDATED:
+		/*
+		 * If the volume is static, a content update might mean the
+		 * size (i.e. used_bytes) was also changed.
+		 */
+		if (nt->vi.vol_type == UBI_STATIC_VOLUME)
+			ubiblock_resize(&nt->vi);
+		break;
+	default:
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block ubiblock_notifier = {
+	.notifier_call = ubiblock_notify,
+};
+
+static struct ubi_volume_desc * __init
+open_volume_desc(const char *name, int ubi_num, int vol_id)
+{
+	if (ubi_num == -1)
+		/* No ubi num, name must be a vol device path */
+		return ubi_open_volume_path(name, UBI_READONLY);
+	else if (vol_id == -1)
+		/* No vol_id, must be vol_name */
+		return ubi_open_volume_nm(ubi_num, name, UBI_READONLY);
+	else
+		return ubi_open_volume(ubi_num, vol_id, UBI_READONLY);
+}
+
+static void __init ubiblock_create_from_param(void)
+{
+	int i, ret = 0;
+	struct ubiblock_param *p;
+	struct ubi_volume_desc *desc;
+	struct ubi_volume_info vi;
+
+	/*
+	 * If there is an error creating one of the ubiblocks, continue on to
+	 * create the following ubiblocks. This helps in a circumstance where
+	 * the kernel command-line specifies multiple block devices and some
+	 * may be broken, but we still want the working ones to come up.
+	 */
+	for (i = 0; i < ubiblock_devs; i++) {
+		p = &ubiblock_param[i];
+
+		desc = open_volume_desc(p->name, p->ubi_num, p->vol_id);
+		if (IS_ERR(desc)) {
+			pr_err(
+			       "UBI: block: can't open volume on ubi%d_%d, err=%ld",
+			       p->ubi_num, p->vol_id, PTR_ERR(desc));
+			continue;
+		}
+
+		ubi_get_volume_info(desc, &vi);
+		ubi_close_volume(desc);
+
+		ret = ubiblock_create(&vi);
+		if (ret) {
+			pr_err(
+			       "UBI: block: can't add '%s' volume on ubi%d_%d, err=%d",
+			       vi.name, p->ubi_num, p->vol_id, ret);
+			continue;
+		}
+	}
+}
+
+static void ubiblock_remove_all(void)
+{
+	struct ubiblock *next;
+	struct ubiblock *dev;
+
+	list_for_each_entry_safe(dev, next, &ubiblock_devices, list) {
+		/* The module is being forcefully removed */
+		WARN_ON(dev->desc);
+		/* Remove from device list */
+		list_del(&dev->list);
+		ubiblock_cleanup(dev);
+		kfree(dev);
+	}
+}
+
+int __init ubiblock_init(void)
+{
+	int ret;
+
+	ubiblock_major = register_blkdev(0, "ubiblock");
+	if (ubiblock_major < 0)
+		return ubiblock_major;
+
+	/*
+	 * Attach block devices from 'block=' module param.
+	 * Even if one block device in the param list fails to come up,
+	 * still allow the module to load and leave any others up.
+	 */
+	ubiblock_create_from_param();
+
+	/*
+	 * Block devices are only created upon user requests, so we ignore
+	 * existing volumes.
+	 */
+	ret = ubi_register_volume_notifier(&ubiblock_notifier, 1);
+	if (ret)
+		goto err_unreg;
+	return 0;
+
+err_unreg:
+	unregister_blkdev(ubiblock_major, "ubiblock");
+	ubiblock_remove_all();
+	return ret;
+}
+
+void __exit ubiblock_exit(void)
+{
+	ubi_unregister_volume_notifier(&ubiblock_notifier);
+	ubiblock_remove_all();
+	unregister_blkdev(ubiblock_major, "ubiblock");
+}