drivers/mtd/ubi/block.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2014 Ezequiel Garcia
   4  * Copyright (c) 2011 Free Electrons
   5  *
   6  * Driver parameter handling strongly based on drivers/mtd/ubi/build.c
   7  *   Copyright (c) International Business Machines Corp., 2006
   8  *   Copyright (c) Nokia Corporation, 2007
   9  *   Authors: Artem Bityutskiy, Frank Haverkamp
  10  */
  11
  12 /*
  13  * Read-only block devices on top of UBI volumes
  14  *
  15  * A simple implementation to allow a block device to be layered on top of a
  16  * UBI volume. The implementation is provided by creating a static 1-to-1
  17  * mapping between the block device and the UBI volume.
  18  *
  19  * The addressed byte is obtained from the addressed block sector, which is
  20  * mapped linearly into the corresponding LEB:
  21  *
  22  *   LEB number = addressed byte / LEB size
  23  *
  24  * This feature is compiled in the UBI core, and adds a 'block' parameter
  25  * to allow early creation of block devices on top of UBI volumes. Runtime
  26  * block creation/removal for UBI volumes is provided through two UBI ioctls:
  27  * UBI_IOCVOLCRBLK and UBI_IOCVOLRMBLK.
  28  */
  29
  30 #include <linux/module.h>
  31 #include <linux/init.h>
  32 #include <linux/err.h>
  33 #include <linux/kernel.h>
  34 #include <linux/list.h>
  35 #include <linux/mutex.h>
  36 #include <linux/slab.h>
  37 #include <linux/mtd/ubi.h>
  38 #include <linux/blkdev.h>
  39 #include <linux/blk-mq.h>
  40 #include <linux/hdreg.h>
  41 #include <linux/scatterlist.h>
  42 #include <linux/idr.h>
  43 #include <asm/div64.h>
  44
  45 #include "ubi-media.h"
  46 #include "ubi.h"
  47
  48 /* Maximum number of supported devices */
  49 #define UBIBLOCK_MAX_DEVICES 32
  50
  51 /* Maximum length of the 'block=' parameter */
  52 #define UBIBLOCK_PARAM_LEN 63
  53
  54 /* Maximum number of comma-separated items in the 'block=' parameter */
  55 #define UBIBLOCK_PARAM_COUNT 2
  56
  57 struct ubiblock_param {
  58         int ubi_num;
  59         int vol_id;
  60         char name[UBIBLOCK_PARAM_LEN+1];
  61 };
  62
  63 struct ubiblock_pdu {
  64         struct ubi_sgl usgl;
  65 };
  66
  67 /* Numbers of elements set in the @ubiblock_param array */
  68 static int ubiblock_devs;
  69
  70 /* MTD devices specification parameters */
  71 static struct ubiblock_param ubiblock_param[UBIBLOCK_MAX_DEVICES];
  72
  73 struct ubiblock {
  74         struct ubi_volume_desc *desc;
  75         int ubi_num;
  76         int vol_id;
  77         int refcnt;
  78         int leb_size;
  79
  80         struct gendisk *gd;
  81         struct request_queue *rq;
  82
  83         struct mutex dev_mutex;
  84         struct list_head list;
  85         struct blk_mq_tag_set tag_set;
  86 };
  87
  88 /* Linked list of all ubiblock instances */
  89 static LIST_HEAD(ubiblock_devices);
  90 static DEFINE_IDR(ubiblock_minor_idr);
  91 /* Protects ubiblock_devices and ubiblock_minor_idr */
  92 static DEFINE_MUTEX(devices_mutex);
  93 static int ubiblock_major;
  94
  95 static int __init ubiblock_set_param(const char *val,
  96                                      const struct kernel_param *kp)
  97 {
  98         int i, ret;
  99         size_t len;
 100         struct ubiblock_param *param;
 101         char buf[UBIBLOCK_PARAM_LEN];
 102         char *pbuf = &buf[0];
 103         char *tokens[UBIBLOCK_PARAM_COUNT];
 104
 105         if (!val)
 106                 return -EINVAL;
 107
 108         len = strnlen(val, UBIBLOCK_PARAM_LEN);
 109         if (len == 0) {
 110                 pr_warn("UBI: block: empty 'block=' parameter - ignored\n");
 111                 return 0;
 112         }
 113
 114         if (len == UBIBLOCK_PARAM_LEN) {
 115                 pr_err("UBI: block: parameter \"%s\" is too long, max. is %d\n",
 116                        val, UBIBLOCK_PARAM_LEN);
 117                 return -EINVAL;
 118         }
 119
 120         strcpy(buf, val);
 121
 122         /* Get rid of the final newline */
 123         if (buf[len - 1] == '\n')
 124                 buf[len - 1] = '\0';
 125
 126         for (i = 0; i < UBIBLOCK_PARAM_COUNT; i++)
 127                 tokens[i] = strsep(&pbuf, ",");
 128
 129         param = &ubiblock_param[ubiblock_devs];
 130         if (tokens[1]) {
 131                 /* Two parameters: can be 'ubi, vol_id' or 'ubi, vol_name' */
 132                 ret = kstrtoint(tokens[0], 10, &param->ubi_num);
 133                 if (ret < 0)
 134                         return -EINVAL;
 135
 136                 /* Second param can be a number or a name */
 137                 ret = kstrtoint(tokens[1], 10, &param->vol_id);
 138                 if (ret < 0) {
 139                         param->vol_id = -1;
 140                         strcpy(param->name, tokens[1]);
 141                 }
 142
 143         } else {
 144                 /* One parameter: must be device path */
 145                 strcpy(param->name, tokens[0]);
 146                 param->ubi_num = -1;
 147                 param->vol_id = -1;
 148         }
 149
 150         ubiblock_devs++;
 151
 152         return 0;
 153 }
 154
 155 static const struct kernel_param_ops ubiblock_param_ops = {
 156         .set    = ubiblock_set_param,
 157 };
 158 module_param_cb(block, &ubiblock_param_ops, NULL, 0);
 159 MODULE_PARM_DESC(block, "Attach block devices to UBI volumes. Parameter format: block=<path|dev,num|dev,name>.\n"
 160                         "Multiple \"block\" parameters may be specified.\n"
 161                         "UBI volumes may be specified by their number, name, or path to the device node.\n"
 162                         "Examples\n"
 163                         "Using the UBI volume path:\n"
 164                         "ubi.block=/dev/ubi0_0\n"
 165                         "Using the UBI device, and the volume name:\n"
 166                         "ubi.block=0,rootfs\n"
 167                         "Using both UBI device number and UBI volume number:\n"
 168                         "ubi.block=0,0\n");
 169
 170 static struct ubiblock *find_dev_nolock(int ubi_num, int vol_id)
 171 {
 172         struct ubiblock *dev;
 173
 174         list_for_each_entry(dev, &ubiblock_devices, list)
 175                 if (dev->ubi_num == ubi_num && dev->vol_id == vol_id)
 176                         return dev;
 177         return NULL;
 178 }
 179
 180 static blk_status_t ubiblock_read(struct request *req)
 181 {
 182         struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
 183         struct ubiblock *dev = req->q->queuedata;
 184         u64 pos = blk_rq_pos(req) << 9;
 185         int to_read = blk_rq_bytes(req);
 186         int bytes_left = to_read;
 187         /* Get LEB:offset address to read from */
 188         int offset = do_div(pos, dev->leb_size);
 189         int leb = pos;
 190         struct req_iterator iter;
 191         struct bio_vec bvec;
 192         int ret;
 193
 194         blk_mq_start_request(req);
 195
 196         /*
 197          * It is safe to ignore the return value of blk_rq_map_sg() because
 198          * the number of sg entries is limited to UBI_MAX_SG_COUNT
 199          * and ubi_read_sg() will check that limit.
 200          */
 201         ubi_sgl_init(&pdu->usgl);
 202         blk_rq_map_sg(req->q, req, pdu->usgl.sg);
 203
 204         while (bytes_left) {
 205                 /*
 206                  * We can only read one LEB at a time. Therefore if the read
 207                  * length is larger than one LEB size, we split the operation.
 208                  */
 209                 if (offset + to_read > dev->leb_size)
 210                         to_read = dev->leb_size - offset;
 211
 212                 ret = ubi_read_sg(dev->desc, leb, &pdu->usgl, offset, to_read);
 213                 if (ret < 0)
 214                         break;
 215
 216                 bytes_left -= to_read;
 217                 to_read = bytes_left;
 218                 leb += 1;
 219                 offset = 0;
 220         }
 221
 222         rq_for_each_segment(bvec, req, iter)
 223                 flush_dcache_page(bvec.bv_page);
 224
 225         blk_mq_end_request(req, errno_to_blk_status(ret));
 226
 227         return BLK_STS_OK;
 228 }
 229
 230 static int ubiblock_open(struct gendisk *disk, blk_mode_t mode)
 231 {
 232         struct ubiblock *dev = disk->private_data;
 233         int ret;
 234
 235         mutex_lock(&dev->dev_mutex);
 236         if (dev->refcnt > 0) {
 237                 /*
 238                  * The volume is already open, just increase the reference
 239                  * counter.
 240                  */
 241                 goto out_done;
 242         }
 243
 244         /*
 245          * We want users to be aware they should only mount us as read-only.
 246          * It's just a paranoid check, as write requests will get rejected
 247          * in any case.
 248          */
 249         if (mode & BLK_OPEN_WRITE) {
 250                 ret = -EROFS;
 251                 goto out_unlock;
 252         }
 253         dev->desc = ubi_open_volume(dev->ubi_num, dev->vol_id, UBI_READONLY);
 254         if (IS_ERR(dev->desc)) {
 255                 dev_err(disk_to_dev(dev->gd), "failed to open ubi volume %d_%d",
 256                         dev->ubi_num, dev->vol_id);
 257                 ret = PTR_ERR(dev->desc);
 258                 dev->desc = NULL;
 259                 goto out_unlock;
 260         }
 261
 262 out_done:
 263         dev->refcnt++;
 264         mutex_unlock(&dev->dev_mutex);
 265         return 0;
 266
 267 out_unlock:
 268         mutex_unlock(&dev->dev_mutex);
 269         return ret;
 270 }
 271
 272 static void ubiblock_release(struct gendisk *gd)
 273 {
 274         struct ubiblock *dev = gd->private_data;
 275
 276         mutex_lock(&dev->dev_mutex);
 277         dev->refcnt--;
 278         if (dev->refcnt == 0) {
 279                 ubi_close_volume(dev->desc);
 280                 dev->desc = NULL;
 281         }
 282         mutex_unlock(&dev->dev_mutex);
 283 }
 284
 285 static int ubiblock_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 286 {
 287         /* Some tools might require this information */
 288         geo->heads = 1;
 289         geo->cylinders = 1;
 290         geo->sectors = get_capacity(bdev->bd_disk);
 291         geo->start = 0;
 292         return 0;
 293 }
 294
 295 static const struct block_device_operations ubiblock_ops = {
 296         .owner = THIS_MODULE,
 297         .open = ubiblock_open,
 298         .release = ubiblock_release,
 299         .getgeo = ubiblock_getgeo,
 300 };
 301
 302 static blk_status_t ubiblock_queue_rq(struct blk_mq_hw_ctx *hctx,
 303                              const struct blk_mq_queue_data *bd)
 304 {
 305         switch (req_op(bd->rq)) {
 306         case REQ_OP_READ:
 307                 return ubiblock_read(bd->rq);
 308         default:
 309                 return BLK_STS_IOERR;
 310         }
 311 }
 312
 313 static int ubiblock_init_request(struct blk_mq_tag_set *set,
 314                 struct request *req, unsigned int hctx_idx,
 315                 unsigned int numa_node)
 316 {
 317         struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
 318
 319         sg_init_table(pdu->usgl.sg, UBI_MAX_SG_COUNT);
 320         return 0;
 321 }
 322
 323 static const struct blk_mq_ops ubiblock_mq_ops = {
 324         .queue_rq       = ubiblock_queue_rq,
 325         .init_request   = ubiblock_init_request,
 326 };
 327
 328 static int calc_disk_capacity(struct ubi_volume_info *vi, u64 *disk_capacity)
 329 {
 330         u64 size = vi->used_bytes >> 9;
 331
 332         if (vi->used_bytes % 512) {
 333                 if (vi->vol_type == UBI_DYNAMIC_VOLUME)
 334                         pr_warn("UBI: block: volume size is not a multiple of 512, last %llu bytes are ignored!\n",
 335                                 vi->used_bytes - (size << 9));
 336                 else
 337                         pr_info("UBI: block: volume size is not a multiple of 512, last %llu bytes are ignored!\n",
 338                                 vi->used_bytes - (size << 9));
 339         }
 340
 341         if ((sector_t)size != size)
 342                 return -EFBIG;
 343
 344         *disk_capacity = size;
 345
 346         return 0;
 347 }
 348
 349 int ubiblock_create(struct ubi_volume_info *vi)
 350 {
 351         struct queue_limits lim = {
 352                 .max_segments           = UBI_MAX_SG_COUNT,
 353         };
 354         struct ubiblock *dev;
 355         struct gendisk *gd;
 356         u64 disk_capacity;
 357         int ret;
 358
 359         ret = calc_disk_capacity(vi, &disk_capacity);
 360         if (ret) {
 361                 return ret;
 362         }
 363
 364         /* Check that the volume isn't already handled */
 365         mutex_lock(&devices_mutex);
 366         if (find_dev_nolock(vi->ubi_num, vi->vol_id)) {
 367                 ret = -EEXIST;
 368                 goto out_unlock;
 369         }
 370
 371         dev = kzalloc(sizeof(struct ubiblock), GFP_KERNEL);
 372         if (!dev) {
 373                 ret = -ENOMEM;
 374                 goto out_unlock;
 375         }
 376
 377         mutex_init(&dev->dev_mutex);
 378
 379         dev->ubi_num = vi->ubi_num;
 380         dev->vol_id = vi->vol_id;
 381         dev->leb_size = vi->usable_leb_size;
 382
 383         dev->tag_set.ops = &ubiblock_mq_ops;
 384         dev->tag_set.queue_depth = 64;
 385         dev->tag_set.numa_node = NUMA_NO_NODE;
 386         dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING;
 387         dev->tag_set.cmd_size = sizeof(struct ubiblock_pdu);
 388         dev->tag_set.driver_data = dev;
 389         dev->tag_set.nr_hw_queues = 1;
 390
 391         ret = blk_mq_alloc_tag_set(&dev->tag_set);
 392         if (ret) {
 393                 pr_err("ubiblock%d_%d: blk_mq_alloc_tag_set failed\n",
 394                         dev->ubi_num, dev->vol_id);
 395                 goto out_free_dev;
 396         }
 397
 398
 399         /* Initialize the gendisk of this ubiblock device */
 400         gd = blk_mq_alloc_disk(&dev->tag_set, &lim, dev);
 401         if (IS_ERR(gd)) {
 402                 ret = PTR_ERR(gd);
 403                 goto out_free_tags;
 404         }
 405
 406         gd->fops = &ubiblock_ops;
 407         gd->major = ubiblock_major;
 408         gd->minors = 1;
 409         gd->first_minor = idr_alloc(&ubiblock_minor_idr, dev, 0, 0, GFP_KERNEL);
 410         if (gd->first_minor < 0) {
 411                 pr_err("ubiblock%d_%d: block: dynamic minor allocation failed\n",
 412                         dev->ubi_num, dev->vol_id);
 413                 ret = -ENODEV;
 414                 goto out_cleanup_disk;
 415         }
 416         gd->flags |= GENHD_FL_NO_PART;
 417         gd->private_data = dev;
 418         sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
 419         set_capacity(gd, disk_capacity);
 420         dev->gd = gd;
 421
 422         dev->rq = gd->queue;
 423
 424         list_add_tail(&dev->list, &ubiblock_devices);
 425
 426         /* Must be the last step: anyone can call file ops from now on */
 427         ret = device_add_disk(vi->dev, dev->gd, NULL);
 428         if (ret)
 429                 goto out_remove_minor;
 430
 431         dev_info(disk_to_dev(dev->gd), "created from ubi%d:%d(%s)",
 432                  dev->ubi_num, dev->vol_id, vi->name);
 433         mutex_unlock(&devices_mutex);
 434         return 0;
 435
 436 out_remove_minor:
 437         list_del(&dev->list);
 438         idr_remove(&ubiblock_minor_idr, gd->first_minor);
 439 out_cleanup_disk:
 440         put_disk(gd);
 441 out_free_tags:
 442         blk_mq_free_tag_set(&dev->tag_set);
 443 out_free_dev:
 444         kfree(dev);
 445 out_unlock:
 446         mutex_unlock(&devices_mutex);
 447
 448         return ret;
 449 }
 450
 451 static void ubiblock_cleanup(struct ubiblock *dev)
 452 {
 453         int id = dev->gd->first_minor;
 454
 455         /* Stop new requests to arrive */
 456         del_gendisk(dev->gd);
 457         /* Finally destroy the blk queue */
 458         dev_info(disk_to_dev(dev->gd), "released");
 459         put_disk(dev->gd);
 460         blk_mq_free_tag_set(&dev->tag_set);
 461         idr_remove(&ubiblock_minor_idr, id);
 462 }
 463
 464 int ubiblock_remove(struct ubi_volume_info *vi)
 465 {
 466         struct ubiblock *dev;
 467         int ret;
 468
 469         mutex_lock(&devices_mutex);
 470         dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
 471         if (!dev) {
 472                 ret = -ENODEV;
 473                 goto out_unlock;
 474         }
 475
 476         /* Found a device, let's lock it so we can check if it's busy */
 477         mutex_lock(&dev->dev_mutex);
 478         if (dev->refcnt > 0) {
 479                 ret = -EBUSY;
 480                 goto out_unlock_dev;
 481         }
 482
 483         /* Remove from device list */
 484         list_del(&dev->list);
 485         ubiblock_cleanup(dev);
 486         mutex_unlock(&dev->dev_mutex);
 487         mutex_unlock(&devices_mutex);
 488
 489         kfree(dev);
 490         return 0;
 491
 492 out_unlock_dev:
 493         mutex_unlock(&dev->dev_mutex);
 494 out_unlock:
 495         mutex_unlock(&devices_mutex);
 496         return ret;
 497 }
 498
 499 static int ubiblock_resize(struct ubi_volume_info *vi)
 500 {
 501         struct ubiblock *dev;
 502         u64 disk_capacity;
 503         int ret;
 504
 505         /*
 506          * Need to lock the device list until we stop using the device,
 507          * otherwise the device struct might get released in
 508          * 'ubiblock_remove()'.
 509          */
 510         mutex_lock(&devices_mutex);
 511         dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
 512         if (!dev) {
 513                 mutex_unlock(&devices_mutex);
 514                 return -ENODEV;
 515         }
 516
 517         ret = calc_disk_capacity(vi, &disk_capacity);
 518         if (ret) {
 519                 mutex_unlock(&devices_mutex);
 520                 if (ret == -EFBIG) {
 521                         dev_warn(disk_to_dev(dev->gd),
 522                                  "the volume is too big (%d LEBs), cannot resize",
 523                                  vi->size);
 524                 }
 525                 return ret;
 526         }
 527
 528         mutex_lock(&dev->dev_mutex);
 529
 530         if (get_capacity(dev->gd) != disk_capacity) {
 531                 set_capacity(dev->gd, disk_capacity);
 532                 dev_info(disk_to_dev(dev->gd), "resized to %lld bytes",
 533                          vi->used_bytes);
 534         }
 535         mutex_unlock(&dev->dev_mutex);
 536         mutex_unlock(&devices_mutex);
 537         return 0;
 538 }
 539
 540 static bool
 541 match_volume_desc(struct ubi_volume_info *vi, const char *name, int ubi_num, int vol_id)
 542 {
 543         int err, len, cur_ubi_num, cur_vol_id;
 544
 545         if (ubi_num == -1) {
 546                 /* No ubi num, name must be a vol device path */
 547                 err = ubi_get_num_by_path(name, &cur_ubi_num, &cur_vol_id);
 548                 if (err || vi->ubi_num != cur_ubi_num || vi->vol_id != cur_vol_id)
 549                         return false;
 550
 551                 return true;
 552         }
 553
 554         if (vol_id == -1) {
 555                 /* Got ubi_num, but no vol_id, name must be volume name */
 556                 if (vi->ubi_num != ubi_num)
 557                         return false;
 558
 559                 len = strnlen(name, UBI_VOL_NAME_MAX + 1);
 560                 if (len < 1 || vi->name_len != len)
 561                         return false;
 562
 563                 if (strcmp(name, vi->name))
 564                         return false;
 565
 566                 return true;
 567         }
 568
 569         if (vi->ubi_num != ubi_num)
 570                 return false;
 571
 572         if (vi->vol_id != vol_id)
 573                 return false;
 574
 575         return true;
 576 }
 577
 578 static void
 579 ubiblock_create_from_param(struct ubi_volume_info *vi)
 580 {
 581         int i, ret = 0;
 582         struct ubiblock_param *p;
 583
 584         /*
 585          * Iterate over ubiblock cmdline parameters. If a parameter matches the
 586          * newly added volume create the ubiblock device for it.
 587          */
 588         for (i = 0; i < ubiblock_devs; i++) {
 589                 p = &ubiblock_param[i];
 590
 591                 if (!match_volume_desc(vi, p->name, p->ubi_num, p->vol_id))
 592                         continue;
 593
 594                 ret = ubiblock_create(vi);
 595                 if (ret) {
 596                         pr_err(
 597                                "UBI: block: can't add '%s' volume on ubi%d_%d, err=%d\n",
 598                                vi->name, p->ubi_num, p->vol_id, ret);
 599                 }
 600                 break;
 601         }
 602 }
 603
 604 static int ubiblock_notify(struct notifier_block *nb,
 605                          unsigned long notification_type, void *ns_ptr)
 606 {
 607         struct ubi_notification *nt = ns_ptr;
 608
 609         switch (notification_type) {
 610         case UBI_VOLUME_ADDED:
 611                 ubiblock_create_from_param(&nt->vi);
 612                 break;
 613         case UBI_VOLUME_REMOVED:
 614                 ubiblock_remove(&nt->vi);
 615                 break;
 616         case UBI_VOLUME_RESIZED:
 617                 ubiblock_resize(&nt->vi);
 618                 break;
 619         case UBI_VOLUME_UPDATED:
 620                 /*
 621                  * If the volume is static, a content update might mean the
 622                  * size (i.e. used_bytes) was also changed.
 623                  */
 624                 if (nt->vi.vol_type == UBI_STATIC_VOLUME)
 625                         ubiblock_resize(&nt->vi);
 626                 break;
 627         default:
 628                 break;
 629         }
 630         return NOTIFY_OK;
 631 }
 632
 633 static struct notifier_block ubiblock_notifier = {
 634         .notifier_call = ubiblock_notify,
 635 };
 636
 637 static void ubiblock_remove_all(void)
 638 {
 639         struct ubiblock *next;
 640         struct ubiblock *dev;
 641
 642         mutex_lock(&devices_mutex);
 643         list_for_each_entry_safe(dev, next, &ubiblock_devices, list) {
 644                 /* The module is being forcefully removed */
 645                 WARN_ON(dev->desc);
 646                 /* Remove from device list */
 647                 list_del(&dev->list);
 648                 ubiblock_cleanup(dev);
 649                 kfree(dev);
 650         }
 651         mutex_unlock(&devices_mutex);
 652 }
 653
 654 int __init ubiblock_init(void)
 655 {
 656         int ret;
 657
 658         ubiblock_major = register_blkdev(0, "ubiblock");
 659         if (ubiblock_major < 0)
 660                 return ubiblock_major;
 661
 662         ret = ubi_register_volume_notifier(&ubiblock_notifier, 0);
 663         if (ret)
 664                 goto err_unreg;
 665         return 0;
 666
 667 err_unreg:
 668         unregister_blkdev(ubiblock_major, "ubiblock");
 669         ubiblock_remove_all();
 670         return ret;
 671 }
 672
 673 void ubiblock_exit(void)
 674 {
 675         ubi_unregister_volume_notifier(&ubiblock_notifier);
 676         ubiblock_remove_all();
 677         unregister_blkdev(ubiblock_major, "ubiblock");
 678 }