target/linux/generic/patches-3.14/040-UBI-R-O-block-driver-on-top-of-UBI-volumes.patch

   1 From 9d54c8a33eec78289b1b3f6e10874719c27ce0a7 Mon Sep 17 00:00:00 2001
   2 From: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
   3 Date: Tue, 25 Feb 2014 13:25:22 -0300
   4 Subject: [PATCH] UBI: R/O block driver on top of UBI volumes
   5
   6 This commit introduces read-only block device emulation on top of UBI volumes.
   7
   8 Given UBI takes care of wear leveling and bad block management it's possible
   9 to add a thin layer to enable block device access to UBI volumes.
  10 This allows to use a block-oriented filesystem on a flash device.
  11
  12 The UBI block devices are meant to be used in conjunction with any
  13 regular, block-oriented file system (e.g. ext4), although it's primarily
  14 targeted at read-only file systems, such as squashfs.
  15
  16 Block devices are created upon user request through new ioctls:
  17 UBI_IOCVOLATTBLK to attach and UBI_IOCVOLDETBLK to detach.
  18 Also, a new UBI module parameter is added 'ubi.block'. This parameter is
  19 needed in order to attach a block device on boot-up time, allowing to
  20 mount the rootfs on a ubiblock device.
  21 For instance, you could have these kernel parameters:
  22
  23   ubi.mtd=5 ubi.block=0,0 root=/dev/ubiblock0_0
  24
  25 Or, if you compile ubi as a module:
  26
  27   $ modprobe ubi mtd=/dev/mtd5 block=/dev/ubi0_0
  28
  29 Artem: amend commentaries and massage the patch a little bit.
  30
  31 Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
  32 Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
  33 ---
  34  drivers/mtd/ubi/Kconfig     |  15 +
  35  drivers/mtd/ubi/Makefile    |   1 +
  36  drivers/mtd/ubi/block.c     | 646 ++++++++++++++++++++++++++++++++++++++++++++
  37  drivers/mtd/ubi/build.c     |  11 +
  38  drivers/mtd/ubi/cdev.c      |  20 ++
  39  drivers/mtd/ubi/ubi.h       |  14 +
  40  include/uapi/mtd/ubi-user.h |  11 +
  41  7 files changed, 718 insertions(+)
  42  create mode 100644 drivers/mtd/ubi/block.c
  43
  44 diff --git a/drivers/mtd/ubi/Kconfig b/drivers/mtd/ubi/Kconfig
  45 index 36663af..783fb18 100644
  46 --- a/drivers/mtd/ubi/Kconfig
  47 +++ b/drivers/mtd/ubi/Kconfig
  48 @@ -87,4 +87,19 @@ config MTD_UBI_GLUEBI
  49            work on top of UBI. Do not enable this unless you use legacy
  50            software.
  51
  52 +config MTD_UBI_BLOCK
  53 +       bool "Read-only block devices on top of UBI volumes"
  54 +       default n
  55 +       help
  56 +          This option enables read-only UBI block devices support. UBI block
  57 +          devices will be layered on top of UBI volumes, which means that the
  58 +          UBI driver will transparently handle things like bad eraseblocks and
  59 +          bit-flips. You can put any block-oriented file system on top of UBI
  60 +          volumes in read-only mode (e.g., ext4), but it is probably most
  61 +          practical for read-only file systems, like squashfs.
  62 +
  63 +          When selected, this feature will be built in the UBI driver.
  64 +
  65 +          If in doubt, say "N".
  66 +
  67  endif # MTD_UBI
  68 diff --git a/drivers/mtd/ubi/Makefile b/drivers/mtd/ubi/Makefile
  69 index b46b0c97..4e3c3d7 100644
  70 --- a/drivers/mtd/ubi/Makefile
  71 +++ b/drivers/mtd/ubi/Makefile
  72 @@ -3,5 +3,6 @@ obj-$(CONFIG_MTD_UBI) += ubi.o
  73  ubi-y += vtbl.o vmt.o upd.o build.o cdev.o kapi.o eba.o io.o wl.o attach.o
  74  ubi-y += misc.o debug.o
  75  ubi-$(CONFIG_MTD_UBI_FASTMAP) += fastmap.o
  76 +ubi-$(CONFIG_MTD_UBI_BLOCK) += block.o
  77
  78  obj-$(CONFIG_MTD_UBI_GLUEBI) += gluebi.o
  79 diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
  80 new file mode 100644
  81 index 0000000..cea7d1c
  82 --- /dev/null
  83 +++ b/drivers/mtd/ubi/block.c
  84 @@ -0,0 +1,646 @@
  85 +/*
  86 + * Copyright (c) 2014 Ezequiel Garcia
  87 + * Copyright (c) 2011 Free Electrons
  88 + *
  89 + * Driver parameter handling strongly based on drivers/mtd/ubi/build.c
  90 + *   Copyright (c) International Business Machines Corp., 2006
  91 + *   Copyright (c) Nokia Corporation, 2007
  92 + *   Authors: Artem Bityutskiy, Frank Haverkamp
  93 + *
  94 + * This program is free software; you can redistribute it and/or modify
  95 + * it under the terms of the GNU General Public License as published by
  96 + * the Free Software Foundation, version 2.
  97 + *
  98 + * This program is distributed in the hope that it will be useful,
  99 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
 100 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
 101 + * the GNU General Public License for more details.
 102 + */
 103 +
 104 +/*
 105 + * Read-only block devices on top of UBI volumes
 106 + *
 107 + * A simple implementation to allow a block device to be layered on top of a
 108 + * UBI volume. The implementation is provided by creating a static 1-to-1
 109 + * mapping between the block device and the UBI volume.
 110 + *
 111 + * The addressed byte is obtained from the addressed block sector, which is
 112 + * mapped linearly into the corresponding LEB:
 113 + *
 114 + *   LEB number = addressed byte / LEB size
 115 + *
 116 + * This feature is compiled in the UBI core, and adds a new 'block' parameter
 117 + * to allow early block device attaching. Runtime  block attach/detach for UBI
 118 + * volumes is provided through two new UBI ioctls: UBI_IOCVOLATTBLK and
 119 + * UBI_IOCVOLDETBLK.
 120 + */
 121 +
 122 +#include <linux/module.h>
 123 +#include <linux/init.h>
 124 +#include <linux/err.h>
 125 +#include <linux/kernel.h>
 126 +#include <linux/list.h>
 127 +#include <linux/mutex.h>
 128 +#include <linux/slab.h>
 129 +#include <linux/vmalloc.h>
 130 +#include <linux/mtd/ubi.h>
 131 +#include <linux/workqueue.h>
 132 +#include <linux/blkdev.h>
 133 +#include <linux/hdreg.h>
 134 +#include <asm/div64.h>
 135 +
 136 +#include "ubi-media.h"
 137 +#include "ubi.h"
 138 +
 139 +/* Maximum number of supported devices */
 140 +#define UBIBLOCK_MAX_DEVICES 32
 141 +
 142 +/* Maximum length of the 'block=' parameter */
 143 +#define UBIBLOCK_PARAM_LEN 63
 144 +
 145 +/* Maximum number of comma-separated items in the 'block=' parameter */
 146 +#define UBIBLOCK_PARAM_COUNT 2
 147 +
 148 +struct ubiblock_param {
 149 +       int ubi_num;
 150 +       int vol_id;
 151 +       char name[UBIBLOCK_PARAM_LEN+1];
 152 +};
 153 +
 154 +/* Numbers of elements set in the @ubiblock_param array */
 155 +static int ubiblock_devs __initdata;
 156 +
 157 +/* MTD devices specification parameters */
 158 +static struct ubiblock_param ubiblock_param[UBIBLOCK_MAX_DEVICES] __initdata;
 159 +
 160 +struct ubiblock {
 161 +       struct ubi_volume_desc *desc;
 162 +       int ubi_num;
 163 +       int vol_id;
 164 +       int refcnt;
 165 +       int leb_size;
 166 +
 167 +       struct gendisk *gd;
 168 +       struct request_queue *rq;
 169 +
 170 +       struct workqueue_struct *wq;
 171 +       struct work_struct work;
 172 +
 173 +       struct mutex dev_mutex;
 174 +       spinlock_t queue_lock;
 175 +       struct list_head list;
 176 +};
 177 +
 178 +/* Linked list of all ubiblock instances */
 179 +static LIST_HEAD(ubiblock_devices);
 180 +static DEFINE_MUTEX(devices_mutex);
 181 +static int ubiblock_major;
 182 +
 183 +static int __init ubiblock_set_param(const char *val,
 184 +                                    const struct kernel_param *kp)
 185 +{
 186 +       int i, ret;
 187 +       size_t len;
 188 +       struct ubiblock_param *param;
 189 +       char buf[UBIBLOCK_PARAM_LEN];
 190 +       char *pbuf = &buf[0];
 191 +       char *tokens[UBIBLOCK_PARAM_COUNT];
 192 +
 193 +       if (!val)
 194 +               return -EINVAL;
 195 +
 196 +       len = strnlen(val, UBIBLOCK_PARAM_LEN);
 197 +       if (len == 0) {
 198 +               ubi_warn("block: empty 'block=' parameter - ignored\n");
 199 +               return 0;
 200 +       }
 201 +
 202 +       if (len == UBIBLOCK_PARAM_LEN) {
 203 +               ubi_err("block: parameter \"%s\" is too long, max. is %d\n",
 204 +                       val, UBIBLOCK_PARAM_LEN);
 205 +               return -EINVAL;
 206 +       }
 207 +
 208 +       strcpy(buf, val);
 209 +
 210 +       /* Get rid of the final newline */
 211 +       if (buf[len - 1] == '\n')
 212 +               buf[len - 1] = '\0';
 213 +
 214 +       for (i = 0; i < UBIBLOCK_PARAM_COUNT; i++)
 215 +               tokens[i] = strsep(&pbuf, ",");
 216 +
 217 +       param = &ubiblock_param[ubiblock_devs];
 218 +       if (tokens[1]) {
 219 +               /* Two parameters: can be 'ubi, vol_id' or 'ubi, vol_name' */
 220 +               ret = kstrtoint(tokens[0], 10, &param->ubi_num);
 221 +               if (ret < 0)
 222 +                       return -EINVAL;
 223 +
 224 +               /* Second param can be a number or a name */
 225 +               ret = kstrtoint(tokens[1], 10, &param->vol_id);
 226 +               if (ret < 0) {
 227 +                       param->vol_id = -1;
 228 +                       strcpy(param->name, tokens[1]);
 229 +               }
 230 +
 231 +       } else {
 232 +               /* One parameter: must be device path */
 233 +               strcpy(param->name, tokens[0]);
 234 +               param->ubi_num = -1;
 235 +               param->vol_id = -1;
 236 +       }
 237 +
 238 +       ubiblock_devs++;
 239 +
 240 +       return 0;
 241 +}
 242 +
 243 +static const struct kernel_param_ops ubiblock_param_ops = {
 244 +       .set    = ubiblock_set_param,
 245 +};
 246 +module_param_cb(block, &ubiblock_param_ops, NULL, 0);
 247 +MODULE_PARM_DESC(block, "Attach block devices to UBI volumes. Parameter format: block=<path|dev,num|dev,name>.\n"
 248 +                       "Multiple \"block\" parameters may be specified.\n"
 249 +                       "UBI volumes may be specified by their number, name, or path to the device node.\n"
 250 +                       "Examples\n"
 251 +                       "Using the UBI volume path:\n"
 252 +                       "ubi.block=/dev/ubi0_0\n"
 253 +                       "Using the UBI device, and the volume name:\n"
 254 +                       "ubi.block=0,rootfs\n"
 255 +                       "Using both UBI device number and UBI volume number:\n"
 256 +                       "ubi.block=0,0\n");
 257 +
 258 +static struct ubiblock *find_dev_nolock(int ubi_num, int vol_id)
 259 +{
 260 +       struct ubiblock *dev;
 261 +
 262 +       list_for_each_entry(dev, &ubiblock_devices, list)
 263 +               if (dev->ubi_num == ubi_num && dev->vol_id == vol_id)
 264 +                       return dev;
 265 +       return NULL;
 266 +}
 267 +
 268 +static int ubiblock_read_to_buf(struct ubiblock *dev, char *buffer,
 269 +                               int leb, int offset, int len)
 270 +{
 271 +       int ret;
 272 +
 273 +       ret = ubi_read(dev->desc, leb, buffer, offset, len);
 274 +       if (ret) {
 275 +               ubi_err("%s ubi_read error %d",
 276 +                       dev->gd->disk_name, ret);
 277 +               return ret;
 278 +       }
 279 +       return 0;
 280 +}
 281 +
 282 +static int ubiblock_read(struct ubiblock *dev, char *buffer,
 283 +                        sector_t sec, int len)
 284 +{
 285 +       int ret, leb, offset;
 286 +       int bytes_left = len;
 287 +       int to_read = len;
 288 +       loff_t pos = sec << 9;
 289 +
 290 +       /* Get LEB:offset address to read from */
 291 +       offset = do_div(pos, dev->leb_size);
 292 +       leb = pos;
 293 +
 294 +       while (bytes_left) {
 295 +               /*
 296 +                * We can only read one LEB at a time. Therefore if the read
 297 +                * length is larger than one LEB size, we split the operation.
 298 +                */
 299 +               if (offset + to_read > dev->leb_size)
 300 +                       to_read = dev->leb_size - offset;
 301 +
 302 +               ret = ubiblock_read_to_buf(dev, buffer, leb, offset, to_read);
 303 +               if (ret)
 304 +                       return ret;
 305 +
 306 +               buffer += to_read;
 307 +               bytes_left -= to_read;
 308 +               to_read = bytes_left;
 309 +               leb += 1;
 310 +               offset = 0;
 311 +       }
 312 +       return 0;
 313 +}
 314 +
 315 +static int do_ubiblock_request(struct ubiblock *dev, struct request *req)
 316 +{
 317 +       int len, ret;
 318 +       sector_t sec;
 319 +
 320 +       if (req->cmd_type != REQ_TYPE_FS)
 321 +               return -EIO;
 322 +
 323 +       if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
 324 +           get_capacity(req->rq_disk))
 325 +               return -EIO;
 326 +
 327 +       if (rq_data_dir(req) != READ)
 328 +               return -ENOSYS; /* Write not implemented */
 329 +
 330 +       sec = blk_rq_pos(req);
 331 +       len = blk_rq_cur_bytes(req);
 332 +
 333 +       /*
 334 +        * Let's prevent the device from being removed while we're doing I/O
 335 +        * work. Notice that this means we serialize all the I/O operations,
 336 +        * but it's probably of no impact given the NAND core serializes
 337 +        * flash access anyway.
 338 +        */
 339 +       mutex_lock(&dev->dev_mutex);
 340 +       ret = ubiblock_read(dev, req->buffer, sec, len);
 341 +       mutex_unlock(&dev->dev_mutex);
 342 +
 343 +       return ret;
 344 +}
 345 +
 346 +static void ubiblock_do_work(struct work_struct *work)
 347 +{
 348 +       struct ubiblock *dev =
 349 +               container_of(work, struct ubiblock, work);
 350 +       struct request_queue *rq = dev->rq;
 351 +       struct request *req;
 352 +       int res;
 353 +
 354 +       spin_lock_irq(rq->queue_lock);
 355 +
 356 +       req = blk_fetch_request(rq);
 357 +       while (req) {
 358 +
 359 +               spin_unlock_irq(rq->queue_lock);
 360 +               res = do_ubiblock_request(dev, req);
 361 +               spin_lock_irq(rq->queue_lock);
 362 +
 363 +               /*
 364 +                * If we're done with this request,
 365 +                * we need to fetch a new one
 366 +                */
 367 +               if (!__blk_end_request_cur(req, res))
 368 +                       req = blk_fetch_request(rq);
 369 +       }
 370 +
 371 +       spin_unlock_irq(rq->queue_lock);
 372 +}
 373 +
 374 +static void ubiblock_request(struct request_queue *rq)
 375 +{
 376 +       struct ubiblock *dev;
 377 +       struct request *req;
 378 +
 379 +       dev = rq->queuedata;
 380 +
 381 +       if (!dev)
 382 +               while ((req = blk_fetch_request(rq)) != NULL)
 383 +                       __blk_end_request_all(req, -ENODEV);
 384 +       else
 385 +               queue_work(dev->wq, &dev->work);
 386 +}
 387 +
 388 +static int ubiblock_open(struct block_device *bdev, fmode_t mode)
 389 +{
 390 +       struct ubiblock *dev = bdev->bd_disk->private_data;
 391 +       int ret;
 392 +
 393 +       mutex_lock(&dev->dev_mutex);
 394 +       if (dev->refcnt > 0) {
 395 +               /*
 396 +                * The volume is already open, just increase the reference
 397 +                * counter.
 398 +                */
 399 +               goto out_done;
 400 +       }
 401 +
 402 +       /*
 403 +        * We want users to be aware they should only mount us as read-only.
 404 +        * It's just a paranoid check, as write requests will get rejected
 405 +        * in any case.
 406 +        */
 407 +       if (mode & FMODE_WRITE) {
 408 +               ret = -EPERM;
 409 +               goto out_unlock;
 410 +       }
 411 +
 412 +       dev->desc = ubi_open_volume(dev->ubi_num, dev->vol_id, UBI_READONLY);
 413 +       if (IS_ERR(dev->desc)) {
 414 +               ubi_err("%s failed to open ubi volume %d_%d",
 415 +                       dev->gd->disk_name, dev->ubi_num, dev->vol_id);
 416 +               ret = PTR_ERR(dev->desc);
 417 +               dev->desc = NULL;
 418 +               goto out_unlock;
 419 +       }
 420 +
 421 +out_done:
 422 +       dev->refcnt++;
 423 +       mutex_unlock(&dev->dev_mutex);
 424 +       return 0;
 425 +
 426 +out_unlock:
 427 +       mutex_unlock(&dev->dev_mutex);
 428 +       return ret;
 429 +}
 430 +
 431 +static void ubiblock_release(struct gendisk *gd, fmode_t mode)
 432 +{
 433 +       struct ubiblock *dev = gd->private_data;
 434 +
 435 +       mutex_lock(&dev->dev_mutex);
 436 +       dev->refcnt--;
 437 +       if (dev->refcnt == 0) {
 438 +               ubi_close_volume(dev->desc);
 439 +               dev->desc = NULL;
 440 +       }
 441 +       mutex_unlock(&dev->dev_mutex);
 442 +}
 443 +
 444 +static int ubiblock_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 445 +{
 446 +       /* Some tools might require this information */
 447 +       geo->heads = 1;
 448 +       geo->cylinders = 1;
 449 +       geo->sectors = get_capacity(bdev->bd_disk);
 450 +       geo->start = 0;
 451 +       return 0;
 452 +}
 453 +
 454 +static const struct block_device_operations ubiblock_ops = {
 455 +       .owner = THIS_MODULE,
 456 +       .open = ubiblock_open,
 457 +       .release = ubiblock_release,
 458 +       .getgeo = ubiblock_getgeo,
 459 +};
 460 +
 461 +int ubiblock_add(struct ubi_volume_info *vi)
 462 +{
 463 +       struct ubiblock *dev;
 464 +       struct gendisk *gd;
 465 +       int disk_capacity;
 466 +       int ret;
 467 +
 468 +       /* Check that the volume isn't already handled */
 469 +       mutex_lock(&devices_mutex);
 470 +       if (find_dev_nolock(vi->ubi_num, vi->vol_id)) {
 471 +               mutex_unlock(&devices_mutex);
 472 +               return -EEXIST;
 473 +       }
 474 +       mutex_unlock(&devices_mutex);
 475 +
 476 +       dev = kzalloc(sizeof(struct ubiblock), GFP_KERNEL);
 477 +       if (!dev)
 478 +               return -ENOMEM;
 479 +
 480 +       mutex_init(&dev->dev_mutex);
 481 +
 482 +       dev->ubi_num = vi->ubi_num;
 483 +       dev->vol_id = vi->vol_id;
 484 +       dev->leb_size = vi->usable_leb_size;
 485 +
 486 +       /* Initialize the gendisk of this ubiblock device */
 487 +       gd = alloc_disk(1);
 488 +       if (!gd) {
 489 +               ubi_err("block: alloc_disk failed");
 490 +               ret = -ENODEV;
 491 +               goto out_free_dev;
 492 +       }
 493 +
 494 +       gd->fops = &ubiblock_ops;
 495 +       gd->major = ubiblock_major;
 496 +       gd->first_minor = dev->ubi_num * UBI_MAX_VOLUMES + dev->vol_id;
 497 +       gd->private_data = dev;
 498 +       sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
 499 +       disk_capacity = (vi->size * vi->usable_leb_size) >> 9;
 500 +       set_capacity(gd, disk_capacity);
 501 +       dev->gd = gd;
 502 +
 503 +       spin_lock_init(&dev->queue_lock);
 504 +       dev->rq = blk_init_queue(ubiblock_request, &dev->queue_lock);
 505 +       if (!dev->rq) {
 506 +               ubi_err("block: blk_init_queue failed");
 507 +               ret = -ENODEV;
 508 +               goto out_put_disk;
 509 +       }
 510 +
 511 +       dev->rq->queuedata = dev;
 512 +       dev->gd->queue = dev->rq;
 513 +
 514 +       /*
 515 +        * Create one workqueue per volume (per registered block device).
 516 +        * Rembember workqueues are cheap, they're not threads.
 517 +        */
 518 +       dev->wq = alloc_workqueue(gd->disk_name, 0, 0);
 519 +       if (!dev->wq)
 520 +               goto out_free_queue;
 521 +       INIT_WORK(&dev->work, ubiblock_do_work);
 522 +
 523 +       mutex_lock(&devices_mutex);
 524 +       list_add_tail(&dev->list, &ubiblock_devices);
 525 +       mutex_unlock(&devices_mutex);
 526 +
 527 +       /* Must be the last step: anyone can call file ops from now on */
 528 +       add_disk(dev->gd);
 529 +       ubi_msg("%s created from ubi%d:%d(%s)",
 530 +               dev->gd->disk_name, dev->ubi_num, dev->vol_id, vi->name);
 531 +       return 0;
 532 +
 533 +out_free_queue:
 534 +       blk_cleanup_queue(dev->rq);
 535 +out_put_disk:
 536 +       put_disk(dev->gd);
 537 +out_free_dev:
 538 +       kfree(dev);
 539 +
 540 +       return ret;
 541 +}
 542 +
 543 +static void ubiblock_cleanup(struct ubiblock *dev)
 544 +{
 545 +       del_gendisk(dev->gd);
 546 +       blk_cleanup_queue(dev->rq);
 547 +       ubi_msg("%s released", dev->gd->disk_name);
 548 +       put_disk(dev->gd);
 549 +}
 550 +
 551 +int ubiblock_del(struct ubi_volume_info *vi)
 552 +{
 553 +       struct ubiblock *dev;
 554 +
 555 +       mutex_lock(&devices_mutex);
 556 +       dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
 557 +       if (!dev) {
 558 +               mutex_unlock(&devices_mutex);
 559 +               return -ENODEV;
 560 +       }
 561 +
 562 +       /* Found a device, let's lock it so we can check if it's busy */
 563 +       mutex_lock(&dev->dev_mutex);
 564 +       if (dev->refcnt > 0) {
 565 +               mutex_unlock(&dev->dev_mutex);
 566 +               mutex_unlock(&devices_mutex);
 567 +               return -EBUSY;
 568 +       }
 569 +
 570 +       /* Remove from device list */
 571 +       list_del(&dev->list);
 572 +       mutex_unlock(&devices_mutex);
 573 +
 574 +       /* Flush pending work and stop this workqueue */
 575 +       destroy_workqueue(dev->wq);
 576 +
 577 +       ubiblock_cleanup(dev);
 578 +       mutex_unlock(&dev->dev_mutex);
 579 +       kfree(dev);
 580 +       return 0;
 581 +}
 582 +
 583 +static void ubiblock_resize(struct ubi_volume_info *vi)
 584 +{
 585 +       struct ubiblock *dev;
 586 +       int disk_capacity;
 587 +
 588 +       /*
 589 +        * Need to lock the device list until we stop using the device,
 590 +        * otherwise the device struct might get released in 'ubiblock_del()'.
 591 +        */
 592 +       mutex_lock(&devices_mutex);
 593 +       dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
 594 +       if (!dev) {
 595 +               mutex_unlock(&devices_mutex);
 596 +               return;
 597 +       }
 598 +
 599 +       mutex_lock(&dev->dev_mutex);
 600 +       disk_capacity = (vi->size * vi->usable_leb_size) >> 9;
 601 +       set_capacity(dev->gd, disk_capacity);
 602 +       ubi_msg("%s resized to %d LEBs", dev->gd->disk_name, vi->size);
 603 +       mutex_unlock(&dev->dev_mutex);
 604 +       mutex_unlock(&devices_mutex);
 605 +}
 606 +
 607 +static int ubiblock_notify(struct notifier_block *nb,
 608 +                        unsigned long notification_type, void *ns_ptr)
 609 +{
 610 +       struct ubi_notification *nt = ns_ptr;
 611 +
 612 +       switch (notification_type) {
 613 +       case UBI_VOLUME_ADDED:
 614 +               /*
 615 +                * We want to enforce explicit block device attaching for
 616 +                * volumes, so when a volume is added we do nothing.
 617 +                */
 618 +               break;
 619 +       case UBI_VOLUME_REMOVED:
 620 +               ubiblock_del(&nt->vi);
 621 +               break;
 622 +       case UBI_VOLUME_RESIZED:
 623 +               ubiblock_resize(&nt->vi);
 624 +               break;
 625 +       default:
 626 +               break;
 627 +       }
 628 +       return NOTIFY_OK;
 629 +}
 630 +
 631 +static struct notifier_block ubiblock_notifier = {
 632 +       .notifier_call = ubiblock_notify,
 633 +};
 634 +
 635 +static struct ubi_volume_desc * __init
 636 +open_volume_desc(const char *name, int ubi_num, int vol_id)
 637 +{
 638 +       if (ubi_num == -1)
 639 +               /* No ubi num, name must be a vol device path */
 640 +               return ubi_open_volume_path(name, UBI_READONLY);
 641 +       else if (vol_id == -1)
 642 +               /* No vol_id, must be vol_name */
 643 +               return ubi_open_volume_nm(ubi_num, name, UBI_READONLY);
 644 +       else
 645 +               return ubi_open_volume(ubi_num, vol_id, UBI_READONLY);
 646 +}
 647 +
 648 +static int __init ubiblock_attach_from_param(void)
 649 +{
 650 +       int i, ret;
 651 +       struct ubiblock_param *p;
 652 +       struct ubi_volume_desc *desc;
 653 +       struct ubi_volume_info vi;
 654 +
 655 +       for (i = 0; i < ubiblock_devs; i++) {
 656 +               p = &ubiblock_param[i];
 657 +
 658 +               desc = open_volume_desc(p->name, p->ubi_num, p->vol_id);
 659 +               if (IS_ERR(desc)) {
 660 +                       ubi_err("block: can't open volume, err=%ld\n",
 661 +                               PTR_ERR(desc));
 662 +                       ret = PTR_ERR(desc);
 663 +                       break;
 664 +               }
 665 +
 666 +               ubi_get_volume_info(desc, &vi);
 667 +               ubi_close_volume(desc);
 668 +
 669 +               ret = ubiblock_add(&vi);
 670 +               if (ret) {
 671 +                       ubi_err("block: can't add '%s' volume, err=%d\n",
 672 +                               vi.name, ret);
 673 +                       break;
 674 +               }
 675 +       }
 676 +       return ret;
 677 +}
 678 +
 679 +static void ubiblock_detach_all(void)
 680 +{
 681 +       struct ubiblock *next;
 682 +       struct ubiblock *dev;
 683 +
 684 +       list_for_each_entry_safe(dev, next, &ubiblock_devices, list) {
 685 +               /* Flush pending work and stop workqueue */
 686 +               destroy_workqueue(dev->wq);
 687 +               /* The module is being forcefully removed */
 688 +               WARN_ON(dev->desc);
 689 +               /* Remove from device list */
 690 +               list_del(&dev->list);
 691 +               ubiblock_cleanup(dev);
 692 +               kfree(dev);
 693 +       }
 694 +}
 695 +
 696 +int __init ubiblock_init(void)
 697 +{
 698 +       int ret;
 699 +
 700 +       ubiblock_major = register_blkdev(0, "ubiblock");
 701 +       if (ubiblock_major < 0)
 702 +               return ubiblock_major;
 703 +
 704 +       /* Attach block devices from 'block=' module param */
 705 +       ret = ubiblock_attach_from_param();
 706 +       if (ret)
 707 +               goto err_detach;
 708 +
 709 +       /*
 710 +        * Block devices needs to be attached to volumes explicitly
 711 +        * upon user request. So we ignore existing volumes.
 712 +        */
 713 +       ret = ubi_register_volume_notifier(&ubiblock_notifier, 1);
 714 +       if (ret)
 715 +               goto err_unreg;
 716 +       return 0;
 717 +
 718 +err_unreg:
 719 +       unregister_blkdev(ubiblock_major, "ubiblock");
 720 +err_detach:
 721 +       ubiblock_detach_all();
 722 +       return ret;
 723 +}
 724 +
 725 +void __exit ubiblock_exit(void)
 726 +{
 727 +       ubi_unregister_volume_notifier(&ubiblock_notifier);
 728 +       ubiblock_detach_all();
 729 +       unregister_blkdev(ubiblock_major, "ubiblock");
 730 +}
 731 diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
 732 index 57deae9..6e30a3c 100644
 733 --- a/drivers/mtd/ubi/build.c
 734 +++ b/drivers/mtd/ubi/build.c
 735 @@ -1298,6 +1298,15 @@ static int __init ubi_init(void)
 736                 }
 737         }
 738
 739 +       err = ubiblock_init();
 740 +       if (err) {
 741 +               ubi_err("block: cannot initialize, error %d", err);
 742 +
 743 +               /* See comment above re-ubi_is_module(). */
 744 +               if (ubi_is_module())
 745 +                       goto out_detach;
 746 +       }
 747 +
 748         return 0;
 749
 750  out_detach:
 751 @@ -1326,6 +1335,8 @@ static void __exit ubi_exit(void)
 752  {
 753         int i;
 754
 755 +       ubiblock_exit();
 756 +
 757         for (i = 0; i < UBI_MAX_DEVICES; i++)
 758                 if (ubi_devices[i]) {
 759                         mutex_lock(&ubi_devices_mutex);
 760 diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
 761 index 8ca49f2..39d3774 100644
 762 --- a/drivers/mtd/ubi/cdev.c
 763 +++ b/drivers/mtd/ubi/cdev.c
 764 @@ -561,6 +561,26 @@ static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
 765                 break;
 766         }
 767
 768 +       /* Attach a block device to an UBI volume */
 769 +       case UBI_IOCVOLATTBLK:
 770 +       {
 771 +               struct ubi_volume_info vi;
 772 +
 773 +               ubi_get_volume_info(desc, &vi);
 774 +               err = ubiblock_add(&vi);
 775 +               break;
 776 +       }
 777 +
 778 +       /* Dettach a block device from an UBI volume */
 779 +       case UBI_IOCVOLDETBLK:
 780 +       {
 781 +               struct ubi_volume_info vi;
 782 +
 783 +               ubi_get_volume_info(desc, &vi);
 784 +               err = ubiblock_del(&vi);
 785 +               break;
 786 +       }
 787 +
 788         default:
 789                 err = -ENOTTY;
 790                 break;
 791 diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
 792 index 8ea6297..e76ff98 100644
 793 --- a/drivers/mtd/ubi/ubi.h
 794 +++ b/drivers/mtd/ubi/ubi.h
 795 @@ -864,6 +864,20 @@ int ubi_update_fastmap(struct ubi_device *ubi);
 796  int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
 797                      int fm_anchor);
 798
 799 +/* block.c */
 800 +#ifdef CONFIG_MTD_UBI_BLOCK
 801 +int ubiblock_init(void);
 802 +void ubiblock_exit(void);
 803 +int ubiblock_add(struct ubi_volume_info *vi);
 804 +int ubiblock_del(struct ubi_volume_info *vi);
 805 +#else
 806 +static inline int ubiblock_init(void) { return 0; }
 807 +static inline void ubiblock_exit(void) {}
 808 +static inline int ubiblock_add(struct ubi_volume_info *vi) { return -ENOTTY; }
 809 +static inline int ubiblock_del(struct ubi_volume_info *vi) { return -ENOTTY; }
 810 +#endif
 811 +
 812 +
 813  /*
 814   * ubi_rb_for_each_entry - walk an RB-tree.
 815   * @rb: a pointer to type 'struct rb_node' to use as a loop counter
 816 diff --git a/include/uapi/mtd/ubi-user.h b/include/uapi/mtd/ubi-user.h
 817 index 723c324..b98585a 100644
 818 --- a/include/uapi/mtd/ubi-user.h
 819 +++ b/include/uapi/mtd/ubi-user.h
 820 @@ -134,6 +134,13 @@
 821   * used. A pointer to a &struct ubi_set_vol_prop_req object is expected to be
 822   * passed. The object describes which property should be set, and to which value
 823   * it should be set.
 824 + *
 825 + * Block devices on UBI volumes
 826 + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 827 + *
 828 + * To attach or detach a block device from an UBI volume the %UBI_IOCVOLATTBLK
 829 + * and %UBI_IOCVOLDETBLK ioctl commands should be used, respectively.
 830 + * These commands take no arguments.
 831   */
 832
 833  /*
 834 @@ -191,6 +198,10 @@
 835  /* Set an UBI volume property */
 836  #define UBI_IOCSETVOLPROP _IOW(UBI_VOL_IOC_MAGIC, 6, \
 837                                struct ubi_set_vol_prop_req)
 838 +/* Attach a block device to an UBI volume */
 839 +#define UBI_IOCVOLATTBLK _IO(UBI_VOL_IOC_MAGIC, 7)
 840 +/* Detach a block device from an UBI volume */
 841 +#define UBI_IOCVOLDETBLK _IO(UBI_VOL_IOC_MAGIC, 8)
 842
 843  /* Maximum MTD device name length supported by UBI */
 844  #define MAX_UBI_MTD_NAME_LEN 127
 845 --
 846 1.9.2
 847