1 /* 2 * Copyright (c) International Business Machines Corp., 2006 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 12 * the GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 17 * 18 * Author: Artem Bityutskiy (Битюцкий Артём) 19 */ 20 21 /* 22 * This file includes implementation of UBI character device operations. 23 * 24 * There are two kinds of character devices in UBI: UBI character devices and 25 * UBI volume character devices. UBI character devices allow users to 26 * manipulate whole volumes: create, remove, and re-size them. Volume character 27 * devices provide volume I/O capabilities. 28 * 29 * Major and minor numbers are assigned dynamically to both UBI and volume 30 * character devices. 31 * 32 * Well, there is the third kind of character devices - the UBI control 33 * character device, which allows to manipulate by UBI devices - create and 34 * delete them. In other words, it is used for attaching and detaching MTD 35 * devices. 36 */ 37 38 #include <linux/module.h> 39 #include <linux/stat.h> 40 #include <linux/ioctl.h> 41 #include <linux/capability.h> 42 #include <mtd/ubi-user.h> 43 #include <asm/uaccess.h> 44 #include <asm/div64.h> 45 #include "ubi.h" 46 47 /** 48 * get_exclusive - get exclusive access to an UBI volume. 49 * @desc: volume descriptor 50 * 51 * This function changes UBI volume open mode to "exclusive". Returns previous 52 * mode value (positive integer) in case of success and a negative error code 53 * in case of failure. 54 */ 55 static int get_exclusive(struct ubi_volume_desc *desc) 56 { 57 int users, err; 58 struct ubi_volume *vol = desc->vol; 59 60 spin_lock(&vol->ubi->volumes_lock); 61 users = vol->readers + vol->writers + vol->exclusive; 62 ubi_assert(users > 0); 63 if (users > 1) { 64 dbg_err("%d users for volume %d", users, vol->vol_id); 65 err = -EBUSY; 66 } else { 67 vol->readers = vol->writers = 0; 68 vol->exclusive = 1; 69 err = desc->mode; 70 desc->mode = UBI_EXCLUSIVE; 71 } 72 spin_unlock(&vol->ubi->volumes_lock); 73 74 return err; 75 } 76 77 /** 78 * revoke_exclusive - revoke exclusive mode. 79 * @desc: volume descriptor 80 * @mode: new mode to switch to 81 */ 82 static void revoke_exclusive(struct ubi_volume_desc *desc, int mode) 83 { 84 struct ubi_volume *vol = desc->vol; 85 86 spin_lock(&vol->ubi->volumes_lock); 87 ubi_assert(vol->readers == 0 && vol->writers == 0); 88 ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE); 89 vol->exclusive = 0; 90 if (mode == UBI_READONLY) 91 vol->readers = 1; 92 else if (mode == UBI_READWRITE) 93 vol->writers = 1; 94 else 95 vol->exclusive = 1; 96 spin_unlock(&vol->ubi->volumes_lock); 97 98 desc->mode = mode; 99 } 100 101 static int vol_cdev_open(struct inode *inode, struct file *file) 102 { 103 struct ubi_volume_desc *desc; 104 int vol_id = iminor(inode) - 1, mode, ubi_num; 105 106 ubi_num = ubi_major2num(imajor(inode)); 107 if (ubi_num < 0) 108 return ubi_num; 109 110 if (file->f_mode & FMODE_WRITE) 111 mode = UBI_READWRITE; 112 else 113 mode = UBI_READONLY; 114 115 dbg_msg("open volume %d, mode %d", vol_id, mode); 116 117 desc = ubi_open_volume(ubi_num, vol_id, mode); 118 if (IS_ERR(desc)) 119 return PTR_ERR(desc); 120 121 file->private_data = desc; 122 return 0; 123 } 124 125 static int vol_cdev_release(struct inode *inode, struct file *file) 126 { 127 struct ubi_volume_desc *desc = file->private_data; 128 struct ubi_volume *vol = desc->vol; 129 130 dbg_msg("release volume %d, mode %d", vol->vol_id, desc->mode); 131 132 if (vol->updating) { 133 ubi_warn("update of volume %d not finished, volume is damaged", 134 vol->vol_id); 135 ubi_assert(!vol->changing_leb); 136 vol->updating = 0; 137 vfree(vol->upd_buf); 138 } else if (vol->changing_leb) { 139 dbg_msg("only %lld of %lld bytes received for atomic LEB change" 140 " for volume %d:%d, cancel", vol->upd_received, 141 vol->upd_bytes, vol->ubi->ubi_num, vol->vol_id); 142 vol->changing_leb = 0; 143 vfree(vol->upd_buf); 144 } 145 146 ubi_close_volume(desc); 147 return 0; 148 } 149 150 static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin) 151 { 152 struct ubi_volume_desc *desc = file->private_data; 153 struct ubi_volume *vol = desc->vol; 154 loff_t new_offset; 155 156 if (vol->updating) { 157 /* Update is in progress, seeking is prohibited */ 158 dbg_err("updating"); 159 return -EBUSY; 160 } 161 162 switch (origin) { 163 case 0: /* SEEK_SET */ 164 new_offset = offset; 165 break; 166 case 1: /* SEEK_CUR */ 167 new_offset = file->f_pos + offset; 168 break; 169 case 2: /* SEEK_END */ 170 new_offset = vol->used_bytes + offset; 171 break; 172 default: 173 return -EINVAL; 174 } 175 176 if (new_offset < 0 || new_offset > vol->used_bytes) { 177 dbg_err("bad seek %lld", new_offset); 178 return -EINVAL; 179 } 180 181 dbg_msg("seek volume %d, offset %lld, origin %d, new offset %lld", 182 vol->vol_id, offset, origin, new_offset); 183 184 file->f_pos = new_offset; 185 return new_offset; 186 } 187 188 static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count, 189 loff_t *offp) 190 { 191 struct ubi_volume_desc *desc = file->private_data; 192 struct ubi_volume *vol = desc->vol; 193 struct ubi_device *ubi = vol->ubi; 194 int err, lnum, off, len, tbuf_size; 195 size_t count_save = count; 196 void *tbuf; 197 uint64_t tmp; 198 199 dbg_msg("read %zd bytes from offset %lld of volume %d", 200 count, *offp, vol->vol_id); 201 202 if (vol->updating) { 203 dbg_err("updating"); 204 return -EBUSY; 205 } 206 if (vol->upd_marker) { 207 dbg_err("damaged volume, update marker is set"); 208 return -EBADF; 209 } 210 if (*offp == vol->used_bytes || count == 0) 211 return 0; 212 213 if (vol->corrupted) 214 dbg_msg("read from corrupted volume %d", vol->vol_id); 215 216 if (*offp + count > vol->used_bytes) 217 count_save = count = vol->used_bytes - *offp; 218 219 tbuf_size = vol->usable_leb_size; 220 if (count < tbuf_size) 221 tbuf_size = ALIGN(count, ubi->min_io_size); 222 tbuf = vmalloc(tbuf_size); 223 if (!tbuf) 224 return -ENOMEM; 225 226 len = count > tbuf_size ? tbuf_size : count; 227 228 tmp = *offp; 229 off = do_div(tmp, vol->usable_leb_size); 230 lnum = tmp; 231 232 do { 233 cond_resched(); 234 235 if (off + len >= vol->usable_leb_size) 236 len = vol->usable_leb_size - off; 237 238 err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0); 239 if (err) 240 break; 241 242 off += len; 243 if (off == vol->usable_leb_size) { 244 lnum += 1; 245 off -= vol->usable_leb_size; 246 } 247 248 count -= len; 249 *offp += len; 250 251 err = copy_to_user(buf, tbuf, len); 252 if (err) { 253 err = -EFAULT; 254 break; 255 } 256 257 buf += len; 258 len = count > tbuf_size ? tbuf_size : count; 259 } while (count); 260 261 vfree(tbuf); 262 return err ? err : count_save - count; 263 } 264 265 #ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO 266 267 /* 268 * This function allows to directly write to dynamic UBI volumes, without 269 * issuing the volume update operation. Available only as a debugging feature. 270 * Very useful for testing UBI. 271 */ 272 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf, 273 size_t count, loff_t *offp) 274 { 275 struct ubi_volume_desc *desc = file->private_data; 276 struct ubi_volume *vol = desc->vol; 277 struct ubi_device *ubi = vol->ubi; 278 int lnum, off, len, tbuf_size, err = 0; 279 size_t count_save = count; 280 char *tbuf; 281 uint64_t tmp; 282 283 dbg_msg("requested: write %zd bytes to offset %lld of volume %u", 284 count, *offp, vol->vol_id); 285 286 if (vol->vol_type == UBI_STATIC_VOLUME) 287 return -EROFS; 288 289 tmp = *offp; 290 off = do_div(tmp, vol->usable_leb_size); 291 lnum = tmp; 292 293 if (off % ubi->min_io_size) { 294 dbg_err("unaligned position"); 295 return -EINVAL; 296 } 297 298 if (*offp + count > vol->used_bytes) 299 count_save = count = vol->used_bytes - *offp; 300 301 /* We can write only in fractions of the minimum I/O unit */ 302 if (count % ubi->min_io_size) { 303 dbg_err("unaligned write length"); 304 return -EINVAL; 305 } 306 307 tbuf_size = vol->usable_leb_size; 308 if (count < tbuf_size) 309 tbuf_size = ALIGN(count, ubi->min_io_size); 310 tbuf = vmalloc(tbuf_size); 311 if (!tbuf) 312 return -ENOMEM; 313 314 len = count > tbuf_size ? tbuf_size : count; 315 316 while (count) { 317 cond_resched(); 318 319 if (off + len >= vol->usable_leb_size) 320 len = vol->usable_leb_size - off; 321 322 err = copy_from_user(tbuf, buf, len); 323 if (err) { 324 err = -EFAULT; 325 break; 326 } 327 328 err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len, 329 UBI_UNKNOWN); 330 if (err) 331 break; 332 333 off += len; 334 if (off == vol->usable_leb_size) { 335 lnum += 1; 336 off -= vol->usable_leb_size; 337 } 338 339 count -= len; 340 *offp += len; 341 buf += len; 342 len = count > tbuf_size ? tbuf_size : count; 343 } 344 345 vfree(tbuf); 346 return err ? err : count_save - count; 347 } 348 349 #else 350 #define vol_cdev_direct_write(file, buf, count, offp) -EPERM 351 #endif /* CONFIG_MTD_UBI_DEBUG_USERSPACE_IO */ 352 353 static ssize_t vol_cdev_write(struct file *file, const char __user *buf, 354 size_t count, loff_t *offp) 355 { 356 int err = 0; 357 struct ubi_volume_desc *desc = file->private_data; 358 struct ubi_volume *vol = desc->vol; 359 struct ubi_device *ubi = vol->ubi; 360 361 if (!vol->updating && !vol->changing_leb) 362 return vol_cdev_direct_write(file, buf, count, offp); 363 364 if (vol->updating) 365 err = ubi_more_update_data(ubi, vol, buf, count); 366 else 367 err = ubi_more_leb_change_data(ubi, vol, buf, count); 368 369 if (err < 0) { 370 ubi_err("cannot accept more %zd bytes of data, error %d", 371 count, err); 372 return err; 373 } 374 375 if (err) { 376 /* 377 * The operation is finished, @err contains number of actually 378 * written bytes. 379 */ 380 count = err; 381 382 if (vol->changing_leb) { 383 revoke_exclusive(desc, UBI_READWRITE); 384 return count; 385 } 386 387 err = ubi_check_volume(ubi, vol->vol_id); 388 if (err < 0) 389 return err; 390 391 if (err) { 392 ubi_warn("volume %d on UBI device %d is corrupted", 393 vol->vol_id, ubi->ubi_num); 394 vol->corrupted = 1; 395 } 396 vol->checked = 1; 397 ubi_gluebi_updated(vol); 398 revoke_exclusive(desc, UBI_READWRITE); 399 } 400 401 return count; 402 } 403 404 static int vol_cdev_ioctl(struct inode *inode, struct file *file, 405 unsigned int cmd, unsigned long arg) 406 { 407 int err = 0; 408 struct ubi_volume_desc *desc = file->private_data; 409 struct ubi_volume *vol = desc->vol; 410 struct ubi_device *ubi = vol->ubi; 411 void __user *argp = (void __user *)arg; 412 413 switch (cmd) { 414 /* Volume update command */ 415 case UBI_IOCVOLUP: 416 { 417 int64_t bytes, rsvd_bytes; 418 419 if (!capable(CAP_SYS_RESOURCE)) { 420 err = -EPERM; 421 break; 422 } 423 424 err = copy_from_user(&bytes, argp, sizeof(int64_t)); 425 if (err) { 426 err = -EFAULT; 427 break; 428 } 429 430 if (desc->mode == UBI_READONLY) { 431 err = -EROFS; 432 break; 433 } 434 435 rsvd_bytes = vol->reserved_pebs * (ubi->leb_size-vol->data_pad); 436 if (bytes < 0 || bytes > rsvd_bytes) { 437 err = -EINVAL; 438 break; 439 } 440 441 err = get_exclusive(desc); 442 if (err < 0) 443 break; 444 445 err = ubi_start_update(ubi, vol, bytes); 446 if (bytes == 0) 447 revoke_exclusive(desc, UBI_READWRITE); 448 break; 449 } 450 451 /* Atomic logical eraseblock change command */ 452 case UBI_IOCEBCH: 453 { 454 struct ubi_leb_change_req req; 455 456 err = copy_from_user(&req, argp, 457 sizeof(struct ubi_leb_change_req)); 458 if (err) { 459 err = -EFAULT; 460 break; 461 } 462 463 if (desc->mode == UBI_READONLY || 464 vol->vol_type == UBI_STATIC_VOLUME) { 465 err = -EROFS; 466 break; 467 } 468 469 /* Validate the request */ 470 err = -EINVAL; 471 if (req.lnum < 0 || req.lnum >= vol->reserved_pebs || 472 req.bytes < 0 || req.lnum >= vol->usable_leb_size) 473 break; 474 if (req.dtype != UBI_LONGTERM && req.dtype != UBI_SHORTTERM && 475 req.dtype != UBI_UNKNOWN) 476 break; 477 478 err = get_exclusive(desc); 479 if (err < 0) 480 break; 481 482 err = ubi_start_leb_change(ubi, vol, &req); 483 if (req.bytes == 0) 484 revoke_exclusive(desc, UBI_READWRITE); 485 break; 486 } 487 488 #ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO 489 /* Logical eraseblock erasure command */ 490 case UBI_IOCEBER: 491 { 492 int32_t lnum; 493 494 err = get_user(lnum, (__user int32_t *)argp); 495 if (err) { 496 err = -EFAULT; 497 break; 498 } 499 500 if (desc->mode == UBI_READONLY || 501 vol->vol_type == UBI_STATIC_VOLUME) { 502 err = -EROFS; 503 break; 504 } 505 506 if (lnum < 0 || lnum >= vol->reserved_pebs) { 507 err = -EINVAL; 508 break; 509 } 510 511 dbg_msg("erase LEB %d:%d", vol->vol_id, lnum); 512 err = ubi_eba_unmap_leb(ubi, vol, lnum); 513 if (err) 514 break; 515 516 err = ubi_wl_flush(ubi); 517 break; 518 } 519 #endif 520 521 default: 522 err = -ENOTTY; 523 break; 524 } 525 526 return err; 527 } 528 529 /** 530 * verify_mkvol_req - verify volume creation request. 531 * @ubi: UBI device description object 532 * @req: the request to check 533 * 534 * This function zero if the request is correct, and %-EINVAL if not. 535 */ 536 static int verify_mkvol_req(const struct ubi_device *ubi, 537 const struct ubi_mkvol_req *req) 538 { 539 int n, err = -EINVAL; 540 541 if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 || 542 req->name_len < 0) 543 goto bad; 544 545 if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) && 546 req->vol_id != UBI_VOL_NUM_AUTO) 547 goto bad; 548 549 if (req->alignment == 0) 550 goto bad; 551 552 if (req->bytes == 0) 553 goto bad; 554 555 if (req->vol_type != UBI_DYNAMIC_VOLUME && 556 req->vol_type != UBI_STATIC_VOLUME) 557 goto bad; 558 559 if (req->alignment > ubi->leb_size) 560 goto bad; 561 562 n = req->alignment % ubi->min_io_size; 563 if (req->alignment != 1 && n) 564 goto bad; 565 566 if (req->name_len > UBI_VOL_NAME_MAX) { 567 err = -ENAMETOOLONG; 568 goto bad; 569 } 570 571 return 0; 572 573 bad: 574 dbg_err("bad volume creation request"); 575 ubi_dbg_dump_mkvol_req(req); 576 return err; 577 } 578 579 /** 580 * verify_rsvol_req - verify volume re-size request. 581 * @ubi: UBI device description object 582 * @req: the request to check 583 * 584 * This function returns zero if the request is correct, and %-EINVAL if not. 585 */ 586 static int verify_rsvol_req(const struct ubi_device *ubi, 587 const struct ubi_rsvol_req *req) 588 { 589 if (req->bytes <= 0) 590 return -EINVAL; 591 592 if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) 593 return -EINVAL; 594 595 return 0; 596 } 597 598 static int ubi_cdev_ioctl(struct inode *inode, struct file *file, 599 unsigned int cmd, unsigned long arg) 600 { 601 int err = 0; 602 struct ubi_device *ubi; 603 struct ubi_volume_desc *desc; 604 void __user *argp = (void __user *)arg; 605 606 if (!capable(CAP_SYS_RESOURCE)) 607 return -EPERM; 608 609 ubi = ubi_get_by_major(imajor(inode)); 610 if (!ubi) 611 return -ENODEV; 612 613 switch (cmd) { 614 /* Create volume command */ 615 case UBI_IOCMKVOL: 616 { 617 struct ubi_mkvol_req req; 618 619 dbg_msg("create volume"); 620 err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req)); 621 if (err) { 622 err = -EFAULT; 623 break; 624 } 625 626 err = verify_mkvol_req(ubi, &req); 627 if (err) 628 break; 629 630 req.name[req.name_len] = '\0'; 631 632 mutex_lock(&ubi->volumes_mutex); 633 err = ubi_create_volume(ubi, &req); 634 mutex_unlock(&ubi->volumes_mutex); 635 if (err) 636 break; 637 638 err = put_user(req.vol_id, (__user int32_t *)argp); 639 if (err) 640 err = -EFAULT; 641 642 break; 643 } 644 645 /* Remove volume command */ 646 case UBI_IOCRMVOL: 647 { 648 int vol_id; 649 650 dbg_msg("remove volume"); 651 err = get_user(vol_id, (__user int32_t *)argp); 652 if (err) { 653 err = -EFAULT; 654 break; 655 } 656 657 desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE); 658 if (IS_ERR(desc)) { 659 err = PTR_ERR(desc); 660 break; 661 } 662 663 mutex_lock(&ubi->volumes_mutex); 664 err = ubi_remove_volume(desc); 665 mutex_unlock(&ubi->volumes_mutex); 666 667 /* 668 * The volume is deleted (unless an error occurred), and the 669 * 'struct ubi_volume' object will be freed when 670 * 'ubi_close_volume()' will call 'put_device()'. 671 */ 672 ubi_close_volume(desc); 673 break; 674 } 675 676 /* Re-size volume command */ 677 case UBI_IOCRSVOL: 678 { 679 int pebs; 680 uint64_t tmp; 681 struct ubi_rsvol_req req; 682 683 dbg_msg("re-size volume"); 684 err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req)); 685 if (err) { 686 err = -EFAULT; 687 break; 688 } 689 690 err = verify_rsvol_req(ubi, &req); 691 if (err) 692 break; 693 694 desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE); 695 if (IS_ERR(desc)) { 696 err = PTR_ERR(desc); 697 break; 698 } 699 700 tmp = req.bytes; 701 pebs = !!do_div(tmp, desc->vol->usable_leb_size); 702 pebs += tmp; 703 704 mutex_lock(&ubi->volumes_mutex); 705 err = ubi_resize_volume(desc, pebs); 706 mutex_unlock(&ubi->volumes_mutex); 707 ubi_close_volume(desc); 708 break; 709 } 710 711 default: 712 err = -ENOTTY; 713 break; 714 } 715 716 ubi_put_device(ubi); 717 return err; 718 } 719 720 static int ctrl_cdev_ioctl(struct inode *inode, struct file *file, 721 unsigned int cmd, unsigned long arg) 722 { 723 int err = 0; 724 void __user *argp = (void __user *)arg; 725 726 if (!capable(CAP_SYS_RESOURCE)) 727 return -EPERM; 728 729 switch (cmd) { 730 /* Attach an MTD device command */ 731 case UBI_IOCATT: 732 { 733 struct ubi_attach_req req; 734 struct mtd_info *mtd; 735 736 dbg_msg("attach MTD device"); 737 err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req)); 738 if (err) { 739 err = -EFAULT; 740 break; 741 } 742 743 if (req.mtd_num < 0 || 744 (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) { 745 err = -EINVAL; 746 break; 747 } 748 749 mtd = get_mtd_device(NULL, req.mtd_num); 750 if (IS_ERR(mtd)) { 751 err = PTR_ERR(mtd); 752 break; 753 } 754 755 /* 756 * Note, further request verification is done by 757 * 'ubi_attach_mtd_dev()'. 758 */ 759 mutex_lock(&ubi_devices_mutex); 760 err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset); 761 mutex_unlock(&ubi_devices_mutex); 762 if (err < 0) 763 put_mtd_device(mtd); 764 else 765 /* @err contains UBI device number */ 766 err = put_user(err, (__user int32_t *)argp); 767 768 break; 769 } 770 771 /* Detach an MTD device command */ 772 case UBI_IOCDET: 773 { 774 int ubi_num; 775 776 dbg_msg("dettach MTD device"); 777 err = get_user(ubi_num, (__user int32_t *)argp); 778 if (err) { 779 err = -EFAULT; 780 break; 781 } 782 783 mutex_lock(&ubi_devices_mutex); 784 err = ubi_detach_mtd_dev(ubi_num, 0); 785 mutex_unlock(&ubi_devices_mutex); 786 break; 787 } 788 789 default: 790 err = -ENOTTY; 791 break; 792 } 793 794 return err; 795 } 796 797 /* UBI control character device operations */ 798 struct file_operations ubi_ctrl_cdev_operations = { 799 .ioctl = ctrl_cdev_ioctl, 800 .owner = THIS_MODULE, 801 }; 802 803 /* UBI character device operations */ 804 struct file_operations ubi_cdev_operations = { 805 .owner = THIS_MODULE, 806 .ioctl = ubi_cdev_ioctl, 807 .llseek = no_llseek, 808 }; 809 810 /* UBI volume character device operations */ 811 struct file_operations ubi_vol_cdev_operations = { 812 .owner = THIS_MODULE, 813 .open = vol_cdev_open, 814 .release = vol_cdev_release, 815 .llseek = vol_cdev_llseek, 816 .read = vol_cdev_read, 817 .write = vol_cdev_write, 818 .ioctl = vol_cdev_ioctl, 819 }; 820