[PATCH v5] ubi: Introduce block devices for UBI volumes
Ezequiel Garcia
ezequiel.garcia at free-electrons.com
Thu Feb 13 14:58:06 EST 2014
This commit introduces block device emulation on top of ubi volumes,
in the most featureless and skinniest way: read-only, uncached access.
Given UBI takes care of wear leveling and bad block management it's possible
to add a thin layer to enable block device access to UBI volumes.
This allows to use a block-oriented filesystem on a flash device.
As opposed to mtdblock, which uses a 1-LEB cache, we've chosen not to
implement any caching policy. The UBI block interface is meant to be
used in conjunction with regular block-oriented filesystems (primarily,
squashfs). These filesystems are better prepared to do their own caching,
rendering a block-level cache useless.
Write support has not been implemented. It's not clear how useful it
would be, given UBI does no wear leveling. This might be added in the
future, using BLKROSET block ioctl to enable.
Block devices are created upon user request through new ioctls:
UBI_IOCVOLATTBLK to attach and UBI_IOCVOLDETBLK to detach.
Also, a new UBI module parameter is added 'ubi.block'. This parameter is
needed in order to attach a block device on boot-up time, allowing to
mount the rootfs on a ubiblock device.
For instance, you could have these kernel parameters:
ubi.mtd=5 ubi.block=0,0 root=/dev/ubiblock0_0
Or, if you compile ubi as a module:
$ modprobe ubi mtd=/dev/mtd5 block=/dev/ubi0_0
Cc: Artem Bityutskiy <dedekind1 at gmail.com>
Cc: David Woodhouse <dwmw2 at infradead.org>
Cc: Brian Norris <computersforpeace at gmail.com>
Cc: Michael Opdenacker <michael.opdenacker at free-electrons.com>
Cc: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
Cc: Mike Frysinger <vapier at gentoo.org>
Cc: Piergiorgio Beruto <piergiorgio.beruto at gmail.com>
Tested-by: Willy Tarreau <w at 1wt.eu>
Reviewed-by: Richard Weinberger <richard.weinberger at gmail.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia at free-electrons.com>
---
drivers/mtd/ubi/Kconfig | 19 ++
drivers/mtd/ubi/Makefile | 1 +
drivers/mtd/ubi/block.c | 656 ++++++++++++++++++++++++++++++++++++++++++++
drivers/mtd/ubi/build.c | 5 +
drivers/mtd/ubi/cdev.c | 20 ++
drivers/mtd/ubi/ubi.h | 14 +
include/uapi/mtd/ubi-user.h | 11 +
7 files changed, 726 insertions(+)
create mode 100644 drivers/mtd/ubi/block.c
diff --git a/drivers/mtd/ubi/Kconfig b/drivers/mtd/ubi/Kconfig
index 36663af..4350bd5 100644
--- a/drivers/mtd/ubi/Kconfig
+++ b/drivers/mtd/ubi/Kconfig
@@ -87,4 +87,23 @@ config MTD_UBI_GLUEBI
work on top of UBI. Do not enable this unless you use legacy
software.
+config MTD_UBI_BLOCK
+ bool "Block device access to UBI volumes"
+ default n
+ help
+ Since UBI already takes care of eraseblock wear leveling
+ and bad block handling, it's possible to implement a block
+ device on top of it and therefore mount regular filesystems
+ (i.e. not flash-oriented, as ext4).
+ In other words, this is a software flash translation layer.
+
+ This can be particularly interesting to allow mounting a read-only
+ filesystem, such as squashfs, on a NAND device.
+
+ When selected, this feature will be built-in the ubi module
+ and block devices will be able to be created and removed using
+ the userspace 'ubiblkvol' tool (provided mtd-utils).
+
+ If in doubt, say "N".
+
endif # MTD_UBI
diff --git a/drivers/mtd/ubi/Makefile b/drivers/mtd/ubi/Makefile
index b46b0c97..4e3c3d7 100644
--- a/drivers/mtd/ubi/Makefile
+++ b/drivers/mtd/ubi/Makefile
@@ -3,5 +3,6 @@ obj-$(CONFIG_MTD_UBI) += ubi.o
ubi-y += vtbl.o vmt.o upd.o build.o cdev.o kapi.o eba.o io.o wl.o attach.o
ubi-y += misc.o debug.o
ubi-$(CONFIG_MTD_UBI_FASTMAP) += fastmap.o
+ubi-$(CONFIG_MTD_UBI_BLOCK) += block.o
obj-$(CONFIG_MTD_UBI_GLUEBI) += gluebi.o
diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
new file mode 100644
index 0000000..5967194
--- /dev/null
+++ b/drivers/mtd/ubi/block.c
@@ -0,0 +1,656 @@
+/*
+ * Copyright (c) 2014 Ezequiel Garcia
+ * Copyright (c) 2011 Free Electrons
+ *
+ * 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.
+ *
+ * A block implementation on UBI volume
+ * ------------------------------------
+ *
+ * How to use this? A bunch of examples worth a thousand words:
+ *
+ * If you want to attach a block device on bootup time, e.g. in order
+ * to mount the rootfs on such a block device:
+ *
+ * Using the UBI volume path:
+ * ubi.block=/dev/ubi0_0
+ *
+ * Using the UBI device, and the volume name:
+ * ubi.block=0,rootfs
+ *
+ * Using both UBI device number and UBI volume number:
+ * ubi.block=0,0
+ *
+ * In this case you would have such kernel parameters:
+ * ubi.mtd=5 ubi.block=0,0 root=/dev/ubiblock0_0
+ *
+ * Of course, if you compile ubi as a module you can use this
+ * parameter on module insertion time:
+ * modprobe ubi mtd=/dev/mtd5 block=/dev/ubi0_0
+ *
+ * For runtime block attaching/detaching, see mtd-utils' ubiblkvol tool.
+ */
+
+#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/vmalloc.h>
+#include <linux/mtd/ubi.h>
+#include <linux/workqueue.h>
+#include <linux/blkdev.h>
+#include <linux/hdreg.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];
+};
+
+/* 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;
+ struct ubi_volume_info *vi;
+ int ubi_num;
+ int vol_id;
+ int refcnt;
+ int leb_size;
+
+ struct gendisk *gd;
+ struct request_queue *rq;
+
+ struct workqueue_struct *wq;
+ struct work_struct work;
+
+ struct mutex vol_mutex;
+ spinlock_t queue_lock;
+ struct list_head list;
+};
+
+/* Linked list of all ubiblock instances */
+static LIST_HEAD(ubiblock_devices);
+static DEFINE_MUTEX(devices_mutex);
+static int ubiblock_major;
+
+/* Ugh! this parameter parsing code is awful */
+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) {
+ ubi_warn("block: empty 'block=' parameter - ignored\n");
+ return 0;
+ }
+
+ if (len == UBIBLOCK_PARAM_LEN) {
+ ubi_err("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, ¶m->ubi_num);
+ if (ret < 0)
+ return -EINVAL;
+
+ /* Second param can be a number or a name */
+ ret = kstrtoint(tokens[1], 10, ¶m->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 const 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_to_buf(struct ubiblock *dev, char *buffer,
+ int leb, int offset, int len)
+{
+ int ret;
+
+ ret = ubi_read(dev->desc, leb, buffer, offset, len);
+ if (ret) {
+ ubi_err("%s ubi_read error %d",
+ dev->gd->disk_name, ret);
+ return ret;
+ }
+ return 0;
+}
+
+static int ubiblock_read(struct ubiblock *dev, char *buffer, int pos, int len)
+{
+ int leb, offset, ret;
+ int bytes_left = len;
+ int to_read = len;
+
+ /* Get leb:offset address to read from */
+ leb = pos / dev->leb_size;
+ offset = pos % dev->leb_size;
+
+ 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 = ubiblock_read_to_buf(dev, buffer, leb, offset, to_read);
+ if (ret)
+ return ret;
+
+ buffer += to_read;
+ bytes_left -= to_read;
+ to_read = bytes_left;
+ leb++;
+ offset = 0;
+ }
+ return 0;
+}
+
+static int do_ubiblock_request(struct ubiblock *dev, struct request *req)
+{
+ int pos, len, ret;
+
+ if (req->cmd_type != REQ_TYPE_FS)
+ return -EIO;
+
+ if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
+ get_capacity(req->rq_disk))
+ return -EIO;
+
+ if (rq_data_dir(req) != READ)
+ return -ENOSYS; /* Write not implemented */
+
+ pos = blk_rq_pos(req) << 9;
+ len = blk_rq_cur_bytes(req);
+
+ /*
+ * Let's prevent the device from being removed while we're doing I/O
+ * work. Notice that this means we serialize all the I/O operations,
+ * but it's probably of no impact given the NAND core serializes
+ * flash acceses anywafy.
+ */
+ mutex_lock(&dev->vol_mutex);
+ ret = ubiblock_read(dev, req->buffer, pos, len);
+ mutex_unlock(&dev->vol_mutex);
+
+ return ret;
+}
+
+static void ubiblock_do_work(struct work_struct *work)
+{
+ struct ubiblock *dev =
+ container_of(work, struct ubiblock, work);
+ struct request_queue *rq = dev->rq;
+ struct request *req;
+ int res;
+
+ spin_lock_irq(rq->queue_lock);
+
+ req = blk_fetch_request(rq);
+ while (req) {
+
+ spin_unlock_irq(rq->queue_lock);
+ res = do_ubiblock_request(dev, req);
+ spin_lock_irq(rq->queue_lock);
+
+ /*
+ * If we're done with this request,
+ * we need to fetch a new one
+ */
+ if (!__blk_end_request_cur(req, res))
+ req = blk_fetch_request(rq);
+ }
+
+ spin_unlock_irq(rq->queue_lock);
+}
+
+static void ubiblock_request(struct request_queue *rq)
+{
+ struct ubiblock *dev;
+ struct request *req;
+
+ 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 ubiblock_open(struct block_device *bdev, fmode_t mode)
+{
+ struct ubiblock *dev = bdev->bd_disk->private_data;
+ int ret;
+
+ mutex_lock(&dev->vol_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)) {
+ ubi_err("%s failed to open ubi volume %d_%d",
+ dev->gd->disk_name, dev->ubi_num, dev->vol_id);
+ ret = PTR_ERR(dev->desc);
+ dev->desc = NULL;
+ goto out_unlock;
+ }
+
+ dev->vi = kzalloc(sizeof(struct ubi_volume_info), GFP_KERNEL);
+ if (!dev->vi) {
+ ret = -ENOMEM;
+ goto out_close;
+ }
+ ubi_get_volume_info(dev->desc, dev->vi);
+ dev->leb_size = dev->vi->usable_leb_size;
+
+out_done:
+ dev->refcnt++;
+ mutex_unlock(&dev->vol_mutex);
+ return 0;
+
+out_close:
+ ubi_close_volume(dev->desc);
+ dev->desc = NULL;
+out_unlock:
+ mutex_unlock(&dev->vol_mutex);
+ return ret;
+}
+
+static void ubiblock_release(struct gendisk *gd, fmode_t mode)
+{
+ struct ubiblock *dev = gd->private_data;
+
+ mutex_lock(&dev->vol_mutex);
+
+ dev->refcnt--;
+ if (dev->refcnt == 0) {
+ kfree(dev->vi);
+ ubi_close_volume(dev->desc);
+
+ dev->vi = NULL;
+ dev->desc = NULL;
+ }
+
+ mutex_unlock(&dev->vol_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,
+};
+
+int ubiblock_add(struct ubi_volume_info *vi)
+{
+ struct ubiblock *dev;
+ struct gendisk *gd;
+ int disk_capacity;
+ int ret;
+
+ /* 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->vol_mutex);
+
+ dev->ubi_num = vi->ubi_num;
+ dev->vol_id = vi->vol_id;
+
+ /* Initialize the gendisk of this ubiblock device */
+ gd = alloc_disk(1);
+ if (!gd) {
+ ubi_err("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);
+ disk_capacity = (vi->size * vi->usable_leb_size) >> 9;
+ set_capacity(gd, disk_capacity);
+ dev->gd = gd;
+
+ spin_lock_init(&dev->queue_lock);
+ dev->rq = blk_init_queue(ubiblock_request, &dev->queue_lock);
+ if (!dev->rq) {
+ ubi_err("block: blk_init_queue failed");
+ ret = -ENODEV;
+ goto out_put_disk;
+ }
+
+ 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(gd->disk_name, 0, 0);
+ if (!dev->wq)
+ goto out_free_queue;
+ INIT_WORK(&dev->work, ubiblock_do_work);
+
+ 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);
+
+ ubi_msg("%s created from ubi%d:%d(%s)",
+ dev->gd->disk_name, dev->ubi_num, dev->vol_id, vi->name);
+
+ return 0;
+
+out_free_queue:
+ blk_cleanup_queue(dev->rq);
+out_put_disk:
+ put_disk(dev->gd);
+out_free_dev:
+ kfree(dev);
+
+ return ret;
+}
+
+static void ubiblock_cleanup(struct ubiblock *dev)
+{
+ del_gendisk(dev->gd);
+ blk_cleanup_queue(dev->rq);
+ ubi_msg("%s released", dev->gd->disk_name);
+ put_disk(dev->gd);
+}
+
+int ubiblock_del(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->vol_mutex);
+
+ if (dev->refcnt > 0) {
+ mutex_unlock(&dev->vol_mutex);
+ mutex_unlock(&devices_mutex);
+ return -EBUSY;
+ }
+
+ /* Remove from device list */
+ list_del(&dev->list);
+ mutex_unlock(&devices_mutex);
+
+ /* Flush pending work and stop this workqueue */
+ destroy_workqueue(dev->wq);
+
+ ubiblock_cleanup(dev);
+ mutex_unlock(&dev->vol_mutex);
+ kfree(dev);
+ return 0;
+}
+
+static void ubiblock_resize(struct ubi_volume_info *vi)
+{
+ struct ubiblock *dev;
+ int disk_capacity;
+
+ /*
+ * Need to lock the device list until we stop using the device,
+ * otherwise the device struct might get released in ubiblock_del().
+ */
+ mutex_lock(&devices_mutex);
+ dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
+ if (!dev) {
+ mutex_unlock(&devices_mutex);
+ return;
+ }
+
+ mutex_lock(&dev->vol_mutex);
+ disk_capacity = (vi->size * vi->usable_leb_size) >> 9;
+ set_capacity(dev->gd, disk_capacity);
+ ubi_msg("%s resized to %d LEBs", dev->gd->disk_name, vi->size);
+ mutex_unlock(&dev->vol_mutex);
+ mutex_unlock(&devices_mutex);
+}
+
+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 attaching for
+ * volumes; so when a volume is added we do nothing.
+ */
+ break;
+ case UBI_VOLUME_REMOVED:
+ ubiblock_del(&nt->vi);
+ break;
+ case UBI_VOLUME_RESIZED:
+ 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_add_from_param(void)
+{
+ int i, ret;
+ struct ubiblock_param *p;
+ struct ubi_volume_desc *desc;
+ struct ubi_volume_info vi;
+
+ 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)) {
+ ubi_warn("block: can't open volume, err=%ld\n",
+ PTR_ERR(desc));
+ continue;
+ }
+
+ ubi_get_volume_info(desc, &vi);
+ ret = ubiblock_add(&vi);
+ if (ret)
+ ubi_warn("block: can't add '%s' volume, err=%d\n",
+ vi.name, ret);
+ ubi_close_volume(desc);
+ }
+}
+
+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 */
+ ubiblock_add_from_param();
+
+ /*
+ * Block devices needs to be attached to volumes explicitly
+ * upon user request. So we ignore existing volumes.
+ */
+ ret = ubi_register_volume_notifier(&ubiblock_notifier, 1);
+ if (ret < 0)
+ unregister_blkdev(ubiblock_major, "ubiblock");
+ return ret;
+}
+
+void __exit ubiblock_exit(void)
+{
+ struct ubiblock *next;
+ struct ubiblock *dev;
+
+ ubi_unregister_volume_notifier(&ubiblock_notifier);
+
+ list_for_each_entry_safe(dev, next, &ubiblock_devices, list) {
+
+ /* Flush pending work and stop workqueue */
+ destroy_workqueue(dev->wq);
+
+ /* The module is being forcefully removed */
+ WARN_ON(dev->desc);
+
+ /* Remove from device list */
+ list_del(&dev->list);
+
+ ubiblock_cleanup(dev);
+
+ kfree(dev);
+ }
+
+ unregister_blkdev(ubiblock_major, "ubiblock");
+}
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 57deae9..a775603 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -1298,6 +1298,9 @@ static int __init ubi_init(void)
}
}
+ if (ubiblock_init() < 0)
+ ubi_warn("cannot init block device access");
+
return 0;
out_detach:
@@ -1326,6 +1329,8 @@ static void __exit ubi_exit(void)
{
int i;
+ ubiblock_exit();
+
for (i = 0; i < UBI_MAX_DEVICES; i++)
if (ubi_devices[i]) {
mutex_lock(&ubi_devices_mutex);
diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index 8ca49f2..39d3774 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -561,6 +561,26 @@ static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
break;
}
+ /* Attach a block device to an UBI volume */
+ case UBI_IOCVOLATTBLK:
+ {
+ struct ubi_volume_info vi;
+
+ ubi_get_volume_info(desc, &vi);
+ err = ubiblock_add(&vi);
+ break;
+ }
+
+ /* Dettach a block device from an UBI volume */
+ case UBI_IOCVOLDETBLK:
+ {
+ struct ubi_volume_info vi;
+
+ ubi_get_volume_info(desc, &vi);
+ err = ubiblock_del(&vi);
+ break;
+ }
+
default:
err = -ENOTTY;
break;
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 8ea6297..e76ff98 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -864,6 +864,20 @@ int ubi_update_fastmap(struct ubi_device *ubi);
int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
int fm_anchor);
+/* block.c */
+#ifdef CONFIG_MTD_UBI_BLOCK
+int ubiblock_init(void);
+void ubiblock_exit(void);
+int ubiblock_add(struct ubi_volume_info *vi);
+int ubiblock_del(struct ubi_volume_info *vi);
+#else
+static inline int ubiblock_init(void) { return 0; }
+static inline void ubiblock_exit(void) {}
+static inline int ubiblock_add(struct ubi_volume_info *vi) { return -ENOTTY; }
+static inline int ubiblock_del(struct ubi_volume_info *vi) { return -ENOTTY; }
+#endif
+
+
/*
* ubi_rb_for_each_entry - walk an RB-tree.
* @rb: a pointer to type 'struct rb_node' to use as a loop counter
diff --git a/include/uapi/mtd/ubi-user.h b/include/uapi/mtd/ubi-user.h
index 723c324..1080762 100644
--- a/include/uapi/mtd/ubi-user.h
+++ b/include/uapi/mtd/ubi-user.h
@@ -134,6 +134,13 @@
* used. A pointer to a &struct ubi_set_vol_prop_req object is expected to be
* passed. The object describes which property should be set, and to which value
* it should be set.
+ *
+ * Block device access to UBI volumes
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * To attach or detach a block device from an UBI volume the %UBI_IOCVOLATTBLK
+ * and %UBI_IOCVOLDETBLK ioctl commands should be used, respectively.
+ * These commands take no arguments.
*/
/*
@@ -191,6 +198,10 @@
/* Set an UBI volume property */
#define UBI_IOCSETVOLPROP _IOW(UBI_VOL_IOC_MAGIC, 6, \
struct ubi_set_vol_prop_req)
+/* Attach a block device to an UBI volume */
+#define UBI_IOCVOLATTBLK _IO(UBI_VOL_IOC_MAGIC, 7)
+/* Detach a block device from an UBI volume */
+#define UBI_IOCVOLDETBLK _IO(UBI_VOL_IOC_MAGIC, 8)
/* Maximum MTD device name length supported by UBI */
#define MAX_UBI_MTD_NAME_LEN 127
--
1.8.1.5
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