Make vfio MSI interrupt be non-threaded.
[kvmfornfv.git] / kernel / drivers / mtd / ubi / cdev.c
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/slab.h>
41 #include <linux/ioctl.h>
42 #include <linux/capability.h>
43 #include <linux/uaccess.h>
44 #include <linux/compat.h>
45 #include <linux/math64.h>
46 #include <mtd/ubi-user.h>
47 #include "ubi.h"
48
49 /**
50  * get_exclusive - get exclusive access to an UBI volume.
51  * @desc: volume descriptor
52  *
53  * This function changes UBI volume open mode to "exclusive". Returns previous
54  * mode value (positive integer) in case of success and a negative error code
55  * in case of failure.
56  */
57 static int get_exclusive(struct ubi_volume_desc *desc)
58 {
59         int users, err;
60         struct ubi_volume *vol = desc->vol;
61
62         spin_lock(&vol->ubi->volumes_lock);
63         users = vol->readers + vol->writers + vol->exclusive + vol->metaonly;
64         ubi_assert(users > 0);
65         if (users > 1) {
66                 ubi_err(vol->ubi, "%d users for volume %d", users, vol->vol_id);
67                 err = -EBUSY;
68         } else {
69                 vol->readers = vol->writers = vol->metaonly = 0;
70                 vol->exclusive = 1;
71                 err = desc->mode;
72                 desc->mode = UBI_EXCLUSIVE;
73         }
74         spin_unlock(&vol->ubi->volumes_lock);
75
76         return err;
77 }
78
79 /**
80  * revoke_exclusive - revoke exclusive mode.
81  * @desc: volume descriptor
82  * @mode: new mode to switch to
83  */
84 static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
85 {
86         struct ubi_volume *vol = desc->vol;
87
88         spin_lock(&vol->ubi->volumes_lock);
89         ubi_assert(vol->readers == 0 && vol->writers == 0 && vol->metaonly == 0);
90         ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
91         vol->exclusive = 0;
92         if (mode == UBI_READONLY)
93                 vol->readers = 1;
94         else if (mode == UBI_READWRITE)
95                 vol->writers = 1;
96         else if (mode == UBI_METAONLY)
97                 vol->metaonly = 1;
98         else
99                 vol->exclusive = 1;
100         spin_unlock(&vol->ubi->volumes_lock);
101
102         desc->mode = mode;
103 }
104
105 static int vol_cdev_open(struct inode *inode, struct file *file)
106 {
107         struct ubi_volume_desc *desc;
108         int vol_id = iminor(inode) - 1, mode, ubi_num;
109
110         ubi_num = ubi_major2num(imajor(inode));
111         if (ubi_num < 0)
112                 return ubi_num;
113
114         if (file->f_mode & FMODE_WRITE)
115                 mode = UBI_READWRITE;
116         else
117                 mode = UBI_READONLY;
118
119         dbg_gen("open device %d, volume %d, mode %d",
120                 ubi_num, vol_id, mode);
121
122         desc = ubi_open_volume(ubi_num, vol_id, mode);
123         if (IS_ERR(desc))
124                 return PTR_ERR(desc);
125
126         file->private_data = desc;
127         return 0;
128 }
129
130 static int vol_cdev_release(struct inode *inode, struct file *file)
131 {
132         struct ubi_volume_desc *desc = file->private_data;
133         struct ubi_volume *vol = desc->vol;
134
135         dbg_gen("release device %d, volume %d, mode %d",
136                 vol->ubi->ubi_num, vol->vol_id, desc->mode);
137
138         if (vol->updating) {
139                 ubi_warn(vol->ubi, "update of volume %d not finished, volume is damaged",
140                          vol->vol_id);
141                 ubi_assert(!vol->changing_leb);
142                 vol->updating = 0;
143                 vfree(vol->upd_buf);
144         } else if (vol->changing_leb) {
145                 dbg_gen("only %lld of %lld bytes received for atomic LEB change for volume %d:%d, cancel",
146                         vol->upd_received, vol->upd_bytes, vol->ubi->ubi_num,
147                         vol->vol_id);
148                 vol->changing_leb = 0;
149                 vfree(vol->upd_buf);
150         }
151
152         ubi_close_volume(desc);
153         return 0;
154 }
155
156 static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
157 {
158         struct ubi_volume_desc *desc = file->private_data;
159         struct ubi_volume *vol = desc->vol;
160
161         if (vol->updating) {
162                 /* Update is in progress, seeking is prohibited */
163                 ubi_err(vol->ubi, "updating");
164                 return -EBUSY;
165         }
166
167         return fixed_size_llseek(file, offset, origin, vol->used_bytes);
168 }
169
170 static int vol_cdev_fsync(struct file *file, loff_t start, loff_t end,
171                           int datasync)
172 {
173         struct ubi_volume_desc *desc = file->private_data;
174         struct ubi_device *ubi = desc->vol->ubi;
175         struct inode *inode = file_inode(file);
176         int err;
177         mutex_lock(&inode->i_mutex);
178         err = ubi_sync(ubi->ubi_num);
179         mutex_unlock(&inode->i_mutex);
180         return err;
181 }
182
183
184 static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
185                              loff_t *offp)
186 {
187         struct ubi_volume_desc *desc = file->private_data;
188         struct ubi_volume *vol = desc->vol;
189         struct ubi_device *ubi = vol->ubi;
190         int err, lnum, off, len,  tbuf_size;
191         size_t count_save = count;
192         void *tbuf;
193
194         dbg_gen("read %zd bytes from offset %lld of volume %d",
195                 count, *offp, vol->vol_id);
196
197         if (vol->updating) {
198                 ubi_err(vol->ubi, "updating");
199                 return -EBUSY;
200         }
201         if (vol->upd_marker) {
202                 ubi_err(vol->ubi, "damaged volume, update marker is set");
203                 return -EBADF;
204         }
205         if (*offp == vol->used_bytes || count == 0)
206                 return 0;
207
208         if (vol->corrupted)
209                 dbg_gen("read from corrupted volume %d", vol->vol_id);
210
211         if (*offp + count > vol->used_bytes)
212                 count_save = count = vol->used_bytes - *offp;
213
214         tbuf_size = vol->usable_leb_size;
215         if (count < tbuf_size)
216                 tbuf_size = ALIGN(count, ubi->min_io_size);
217         tbuf = vmalloc(tbuf_size);
218         if (!tbuf)
219                 return -ENOMEM;
220
221         len = count > tbuf_size ? tbuf_size : count;
222         lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
223
224         do {
225                 cond_resched();
226
227                 if (off + len >= vol->usable_leb_size)
228                         len = vol->usable_leb_size - off;
229
230                 err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
231                 if (err)
232                         break;
233
234                 off += len;
235                 if (off == vol->usable_leb_size) {
236                         lnum += 1;
237                         off -= vol->usable_leb_size;
238                 }
239
240                 count -= len;
241                 *offp += len;
242
243                 err = copy_to_user(buf, tbuf, len);
244                 if (err) {
245                         err = -EFAULT;
246                         break;
247                 }
248
249                 buf += len;
250                 len = count > tbuf_size ? tbuf_size : count;
251         } while (count);
252
253         vfree(tbuf);
254         return err ? err : count_save - count;
255 }
256
257 /*
258  * This function allows to directly write to dynamic UBI volumes, without
259  * issuing the volume update operation.
260  */
261 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
262                                      size_t count, loff_t *offp)
263 {
264         struct ubi_volume_desc *desc = file->private_data;
265         struct ubi_volume *vol = desc->vol;
266         struct ubi_device *ubi = vol->ubi;
267         int lnum, off, len, tbuf_size, err = 0;
268         size_t count_save = count;
269         char *tbuf;
270
271         if (!vol->direct_writes)
272                 return -EPERM;
273
274         dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
275                 count, *offp, vol->vol_id);
276
277         if (vol->vol_type == UBI_STATIC_VOLUME)
278                 return -EROFS;
279
280         lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
281         if (off & (ubi->min_io_size - 1)) {
282                 ubi_err(ubi, "unaligned position");
283                 return -EINVAL;
284         }
285
286         if (*offp + count > vol->used_bytes)
287                 count_save = count = vol->used_bytes - *offp;
288
289         /* We can write only in fractions of the minimum I/O unit */
290         if (count & (ubi->min_io_size - 1)) {
291                 ubi_err(ubi, "unaligned write length");
292                 return -EINVAL;
293         }
294
295         tbuf_size = vol->usable_leb_size;
296         if (count < tbuf_size)
297                 tbuf_size = ALIGN(count, ubi->min_io_size);
298         tbuf = vmalloc(tbuf_size);
299         if (!tbuf)
300                 return -ENOMEM;
301
302         len = count > tbuf_size ? tbuf_size : count;
303
304         while (count) {
305                 cond_resched();
306
307                 if (off + len >= vol->usable_leb_size)
308                         len = vol->usable_leb_size - off;
309
310                 err = copy_from_user(tbuf, buf, len);
311                 if (err) {
312                         err = -EFAULT;
313                         break;
314                 }
315
316                 err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len);
317                 if (err)
318                         break;
319
320                 off += len;
321                 if (off == vol->usable_leb_size) {
322                         lnum += 1;
323                         off -= vol->usable_leb_size;
324                 }
325
326                 count -= len;
327                 *offp += len;
328                 buf += len;
329                 len = count > tbuf_size ? tbuf_size : count;
330         }
331
332         vfree(tbuf);
333         return err ? err : count_save - count;
334 }
335
336 static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
337                               size_t count, loff_t *offp)
338 {
339         int err = 0;
340         struct ubi_volume_desc *desc = file->private_data;
341         struct ubi_volume *vol = desc->vol;
342         struct ubi_device *ubi = vol->ubi;
343
344         if (!vol->updating && !vol->changing_leb)
345                 return vol_cdev_direct_write(file, buf, count, offp);
346
347         if (vol->updating)
348                 err = ubi_more_update_data(ubi, vol, buf, count);
349         else
350                 err = ubi_more_leb_change_data(ubi, vol, buf, count);
351
352         if (err < 0) {
353                 ubi_err(ubi, "cannot accept more %zd bytes of data, error %d",
354                         count, err);
355                 return err;
356         }
357
358         if (err) {
359                 /*
360                  * The operation is finished, @err contains number of actually
361                  * written bytes.
362                  */
363                 count = err;
364
365                 if (vol->changing_leb) {
366                         revoke_exclusive(desc, UBI_READWRITE);
367                         return count;
368                 }
369
370                 err = ubi_check_volume(ubi, vol->vol_id);
371                 if (err < 0)
372                         return err;
373
374                 if (err) {
375                         ubi_warn(ubi, "volume %d on UBI device %d is corrupted",
376                                  vol->vol_id, ubi->ubi_num);
377                         vol->corrupted = 1;
378                 }
379                 vol->checked = 1;
380                 ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
381                 revoke_exclusive(desc, UBI_READWRITE);
382         }
383
384         return count;
385 }
386
387 static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
388                            unsigned long arg)
389 {
390         int err = 0;
391         struct ubi_volume_desc *desc = file->private_data;
392         struct ubi_volume *vol = desc->vol;
393         struct ubi_device *ubi = vol->ubi;
394         void __user *argp = (void __user *)arg;
395
396         switch (cmd) {
397         /* Volume update command */
398         case UBI_IOCVOLUP:
399         {
400                 int64_t bytes, rsvd_bytes;
401
402                 if (!capable(CAP_SYS_RESOURCE)) {
403                         err = -EPERM;
404                         break;
405                 }
406
407                 err = copy_from_user(&bytes, argp, sizeof(int64_t));
408                 if (err) {
409                         err = -EFAULT;
410                         break;
411                 }
412
413                 if (desc->mode == UBI_READONLY) {
414                         err = -EROFS;
415                         break;
416                 }
417
418                 rsvd_bytes = (long long)vol->reserved_pebs *
419                                         ubi->leb_size-vol->data_pad;
420                 if (bytes < 0 || bytes > rsvd_bytes) {
421                         err = -EINVAL;
422                         break;
423                 }
424
425                 err = get_exclusive(desc);
426                 if (err < 0)
427                         break;
428
429                 err = ubi_start_update(ubi, vol, bytes);
430                 if (bytes == 0) {
431                         ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
432                         revoke_exclusive(desc, UBI_READWRITE);
433                 }
434                 break;
435         }
436
437         /* Atomic logical eraseblock change command */
438         case UBI_IOCEBCH:
439         {
440                 struct ubi_leb_change_req req;
441
442                 err = copy_from_user(&req, argp,
443                                      sizeof(struct ubi_leb_change_req));
444                 if (err) {
445                         err = -EFAULT;
446                         break;
447                 }
448
449                 if (desc->mode == UBI_READONLY ||
450                     vol->vol_type == UBI_STATIC_VOLUME) {
451                         err = -EROFS;
452                         break;
453                 }
454
455                 /* Validate the request */
456                 err = -EINVAL;
457                 if (req.lnum < 0 || req.lnum >= vol->reserved_pebs ||
458                     req.bytes < 0 || req.bytes > vol->usable_leb_size)
459                         break;
460
461                 err = get_exclusive(desc);
462                 if (err < 0)
463                         break;
464
465                 err = ubi_start_leb_change(ubi, vol, &req);
466                 if (req.bytes == 0)
467                         revoke_exclusive(desc, UBI_READWRITE);
468                 break;
469         }
470
471         /* Logical eraseblock erasure command */
472         case UBI_IOCEBER:
473         {
474                 int32_t lnum;
475
476                 err = get_user(lnum, (__user int32_t *)argp);
477                 if (err) {
478                         err = -EFAULT;
479                         break;
480                 }
481
482                 if (desc->mode == UBI_READONLY ||
483                     vol->vol_type == UBI_STATIC_VOLUME) {
484                         err = -EROFS;
485                         break;
486                 }
487
488                 if (lnum < 0 || lnum >= vol->reserved_pebs) {
489                         err = -EINVAL;
490                         break;
491                 }
492
493                 dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
494                 err = ubi_eba_unmap_leb(ubi, vol, lnum);
495                 if (err)
496                         break;
497
498                 err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);
499                 break;
500         }
501
502         /* Logical eraseblock map command */
503         case UBI_IOCEBMAP:
504         {
505                 struct ubi_map_req req;
506
507                 err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
508                 if (err) {
509                         err = -EFAULT;
510                         break;
511                 }
512                 err = ubi_leb_map(desc, req.lnum);
513                 break;
514         }
515
516         /* Logical eraseblock un-map command */
517         case UBI_IOCEBUNMAP:
518         {
519                 int32_t lnum;
520
521                 err = get_user(lnum, (__user int32_t *)argp);
522                 if (err) {
523                         err = -EFAULT;
524                         break;
525                 }
526                 err = ubi_leb_unmap(desc, lnum);
527                 break;
528         }
529
530         /* Check if logical eraseblock is mapped command */
531         case UBI_IOCEBISMAP:
532         {
533                 int32_t lnum;
534
535                 err = get_user(lnum, (__user int32_t *)argp);
536                 if (err) {
537                         err = -EFAULT;
538                         break;
539                 }
540                 err = ubi_is_mapped(desc, lnum);
541                 break;
542         }
543
544         /* Set volume property command */
545         case UBI_IOCSETVOLPROP:
546         {
547                 struct ubi_set_vol_prop_req req;
548
549                 err = copy_from_user(&req, argp,
550                                      sizeof(struct ubi_set_vol_prop_req));
551                 if (err) {
552                         err = -EFAULT;
553                         break;
554                 }
555                 switch (req.property) {
556                 case UBI_VOL_PROP_DIRECT_WRITE:
557                         mutex_lock(&ubi->device_mutex);
558                         desc->vol->direct_writes = !!req.value;
559                         mutex_unlock(&ubi->device_mutex);
560                         break;
561                 default:
562                         err = -EINVAL;
563                         break;
564                 }
565                 break;
566         }
567
568         /* Create a R/O block device on top of the UBI volume */
569         case UBI_IOCVOLCRBLK:
570         {
571                 struct ubi_volume_info vi;
572
573                 ubi_get_volume_info(desc, &vi);
574                 err = ubiblock_create(&vi);
575                 break;
576         }
577
578         /* Remove the R/O block device */
579         case UBI_IOCVOLRMBLK:
580         {
581                 struct ubi_volume_info vi;
582
583                 ubi_get_volume_info(desc, &vi);
584                 err = ubiblock_remove(&vi);
585                 break;
586         }
587
588         default:
589                 err = -ENOTTY;
590                 break;
591         }
592         return err;
593 }
594
595 /**
596  * verify_mkvol_req - verify volume creation request.
597  * @ubi: UBI device description object
598  * @req: the request to check
599  *
600  * This function zero if the request is correct, and %-EINVAL if not.
601  */
602 static int verify_mkvol_req(const struct ubi_device *ubi,
603                             const struct ubi_mkvol_req *req)
604 {
605         int n, err = -EINVAL;
606
607         if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
608             req->name_len < 0)
609                 goto bad;
610
611         if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
612             req->vol_id != UBI_VOL_NUM_AUTO)
613                 goto bad;
614
615         if (req->alignment == 0)
616                 goto bad;
617
618         if (req->bytes == 0)
619                 goto bad;
620
621         if (req->vol_type != UBI_DYNAMIC_VOLUME &&
622             req->vol_type != UBI_STATIC_VOLUME)
623                 goto bad;
624
625         if (req->alignment > ubi->leb_size)
626                 goto bad;
627
628         n = req->alignment & (ubi->min_io_size - 1);
629         if (req->alignment != 1 && n)
630                 goto bad;
631
632         if (!req->name[0] || !req->name_len)
633                 goto bad;
634
635         if (req->name_len > UBI_VOL_NAME_MAX) {
636                 err = -ENAMETOOLONG;
637                 goto bad;
638         }
639
640         n = strnlen(req->name, req->name_len + 1);
641         if (n != req->name_len)
642                 goto bad;
643
644         return 0;
645
646 bad:
647         ubi_err(ubi, "bad volume creation request");
648         ubi_dump_mkvol_req(req);
649         return err;
650 }
651
652 /**
653  * verify_rsvol_req - verify volume re-size request.
654  * @ubi: UBI device description object
655  * @req: the request to check
656  *
657  * This function returns zero if the request is correct, and %-EINVAL if not.
658  */
659 static int verify_rsvol_req(const struct ubi_device *ubi,
660                             const struct ubi_rsvol_req *req)
661 {
662         if (req->bytes <= 0)
663                 return -EINVAL;
664
665         if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
666                 return -EINVAL;
667
668         return 0;
669 }
670
671 /**
672  * rename_volumes - rename UBI volumes.
673  * @ubi: UBI device description object
674  * @req: volumes re-name request
675  *
676  * This is a helper function for the volume re-name IOCTL which validates the
677  * the request, opens the volume and calls corresponding volumes management
678  * function. Returns zero in case of success and a negative error code in case
679  * of failure.
680  */
681 static int rename_volumes(struct ubi_device *ubi,
682                           struct ubi_rnvol_req *req)
683 {
684         int i, n, err;
685         struct list_head rename_list;
686         struct ubi_rename_entry *re, *re1;
687
688         if (req->count < 0 || req->count > UBI_MAX_RNVOL)
689                 return -EINVAL;
690
691         if (req->count == 0)
692                 return 0;
693
694         /* Validate volume IDs and names in the request */
695         for (i = 0; i < req->count; i++) {
696                 if (req->ents[i].vol_id < 0 ||
697                     req->ents[i].vol_id >= ubi->vtbl_slots)
698                         return -EINVAL;
699                 if (req->ents[i].name_len < 0)
700                         return -EINVAL;
701                 if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
702                         return -ENAMETOOLONG;
703                 req->ents[i].name[req->ents[i].name_len] = '\0';
704                 n = strlen(req->ents[i].name);
705                 if (n != req->ents[i].name_len)
706                         return -EINVAL;
707         }
708
709         /* Make sure volume IDs and names are unique */
710         for (i = 0; i < req->count - 1; i++) {
711                 for (n = i + 1; n < req->count; n++) {
712                         if (req->ents[i].vol_id == req->ents[n].vol_id) {
713                                 ubi_err(ubi, "duplicated volume id %d",
714                                         req->ents[i].vol_id);
715                                 return -EINVAL;
716                         }
717                         if (!strcmp(req->ents[i].name, req->ents[n].name)) {
718                                 ubi_err(ubi, "duplicated volume name \"%s\"",
719                                         req->ents[i].name);
720                                 return -EINVAL;
721                         }
722                 }
723         }
724
725         /* Create the re-name list */
726         INIT_LIST_HEAD(&rename_list);
727         for (i = 0; i < req->count; i++) {
728                 int vol_id = req->ents[i].vol_id;
729                 int name_len = req->ents[i].name_len;
730                 const char *name = req->ents[i].name;
731
732                 re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
733                 if (!re) {
734                         err = -ENOMEM;
735                         goto out_free;
736                 }
737
738                 re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_METAONLY);
739                 if (IS_ERR(re->desc)) {
740                         err = PTR_ERR(re->desc);
741                         ubi_err(ubi, "cannot open volume %d, error %d",
742                                 vol_id, err);
743                         kfree(re);
744                         goto out_free;
745                 }
746
747                 /* Skip this re-naming if the name does not really change */
748                 if (re->desc->vol->name_len == name_len &&
749                     !memcmp(re->desc->vol->name, name, name_len)) {
750                         ubi_close_volume(re->desc);
751                         kfree(re);
752                         continue;
753                 }
754
755                 re->new_name_len = name_len;
756                 memcpy(re->new_name, name, name_len);
757                 list_add_tail(&re->list, &rename_list);
758                 dbg_gen("will rename volume %d from \"%s\" to \"%s\"",
759                         vol_id, re->desc->vol->name, name);
760         }
761
762         if (list_empty(&rename_list))
763                 return 0;
764
765         /* Find out the volumes which have to be removed */
766         list_for_each_entry(re, &rename_list, list) {
767                 struct ubi_volume_desc *desc;
768                 int no_remove_needed = 0;
769
770                 /*
771                  * Volume @re->vol_id is going to be re-named to
772                  * @re->new_name, while its current name is @name. If a volume
773                  * with name @re->new_name currently exists, it has to be
774                  * removed, unless it is also re-named in the request (@req).
775                  */
776                 list_for_each_entry(re1, &rename_list, list) {
777                         if (re->new_name_len == re1->desc->vol->name_len &&
778                             !memcmp(re->new_name, re1->desc->vol->name,
779                                     re1->desc->vol->name_len)) {
780                                 no_remove_needed = 1;
781                                 break;
782                         }
783                 }
784
785                 if (no_remove_needed)
786                         continue;
787
788                 /*
789                  * It seems we need to remove volume with name @re->new_name,
790                  * if it exists.
791                  */
792                 desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
793                                           UBI_EXCLUSIVE);
794                 if (IS_ERR(desc)) {
795                         err = PTR_ERR(desc);
796                         if (err == -ENODEV)
797                                 /* Re-naming into a non-existing volume name */
798                                 continue;
799
800                         /* The volume exists but busy, or an error occurred */
801                         ubi_err(ubi, "cannot open volume \"%s\", error %d",
802                                 re->new_name, err);
803                         goto out_free;
804                 }
805
806                 re1 = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
807                 if (!re1) {
808                         err = -ENOMEM;
809                         ubi_close_volume(desc);
810                         goto out_free;
811                 }
812
813                 re1->remove = 1;
814                 re1->desc = desc;
815                 list_add(&re1->list, &rename_list);
816                 dbg_gen("will remove volume %d, name \"%s\"",
817                         re1->desc->vol->vol_id, re1->desc->vol->name);
818         }
819
820         mutex_lock(&ubi->device_mutex);
821         err = ubi_rename_volumes(ubi, &rename_list);
822         mutex_unlock(&ubi->device_mutex);
823
824 out_free:
825         list_for_each_entry_safe(re, re1, &rename_list, list) {
826                 ubi_close_volume(re->desc);
827                 list_del(&re->list);
828                 kfree(re);
829         }
830         return err;
831 }
832
833 static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
834                            unsigned long arg)
835 {
836         int err = 0;
837         struct ubi_device *ubi;
838         struct ubi_volume_desc *desc;
839         void __user *argp = (void __user *)arg;
840
841         if (!capable(CAP_SYS_RESOURCE))
842                 return -EPERM;
843
844         ubi = ubi_get_by_major(imajor(file->f_mapping->host));
845         if (!ubi)
846                 return -ENODEV;
847
848         switch (cmd) {
849         /* Create volume command */
850         case UBI_IOCMKVOL:
851         {
852                 struct ubi_mkvol_req req;
853
854                 dbg_gen("create volume");
855                 err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));
856                 if (err) {
857                         err = -EFAULT;
858                         break;
859                 }
860
861                 err = verify_mkvol_req(ubi, &req);
862                 if (err)
863                         break;
864
865                 mutex_lock(&ubi->device_mutex);
866                 err = ubi_create_volume(ubi, &req);
867                 mutex_unlock(&ubi->device_mutex);
868                 if (err)
869                         break;
870
871                 err = put_user(req.vol_id, (__user int32_t *)argp);
872                 if (err)
873                         err = -EFAULT;
874
875                 break;
876         }
877
878         /* Remove volume command */
879         case UBI_IOCRMVOL:
880         {
881                 int vol_id;
882
883                 dbg_gen("remove volume");
884                 err = get_user(vol_id, (__user int32_t *)argp);
885                 if (err) {
886                         err = -EFAULT;
887                         break;
888                 }
889
890                 desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
891                 if (IS_ERR(desc)) {
892                         err = PTR_ERR(desc);
893                         break;
894                 }
895
896                 mutex_lock(&ubi->device_mutex);
897                 err = ubi_remove_volume(desc, 0);
898                 mutex_unlock(&ubi->device_mutex);
899
900                 /*
901                  * The volume is deleted (unless an error occurred), and the
902                  * 'struct ubi_volume' object will be freed when
903                  * 'ubi_close_volume()' will call 'put_device()'.
904                  */
905                 ubi_close_volume(desc);
906                 break;
907         }
908
909         /* Re-size volume command */
910         case UBI_IOCRSVOL:
911         {
912                 int pebs;
913                 struct ubi_rsvol_req req;
914
915                 dbg_gen("re-size volume");
916                 err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));
917                 if (err) {
918                         err = -EFAULT;
919                         break;
920                 }
921
922                 err = verify_rsvol_req(ubi, &req);
923                 if (err)
924                         break;
925
926                 desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
927                 if (IS_ERR(desc)) {
928                         err = PTR_ERR(desc);
929                         break;
930                 }
931
932                 pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
933                                desc->vol->usable_leb_size);
934
935                 mutex_lock(&ubi->device_mutex);
936                 err = ubi_resize_volume(desc, pebs);
937                 mutex_unlock(&ubi->device_mutex);
938                 ubi_close_volume(desc);
939                 break;
940         }
941
942         /* Re-name volumes command */
943         case UBI_IOCRNVOL:
944         {
945                 struct ubi_rnvol_req *req;
946
947                 dbg_gen("re-name volumes");
948                 req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
949                 if (!req) {
950                         err = -ENOMEM;
951                         break;
952                 };
953
954                 err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
955                 if (err) {
956                         err = -EFAULT;
957                         kfree(req);
958                         break;
959                 }
960
961                 err = rename_volumes(ubi, req);
962                 kfree(req);
963                 break;
964         }
965
966         default:
967                 err = -ENOTTY;
968                 break;
969         }
970
971         ubi_put_device(ubi);
972         return err;
973 }
974
975 static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
976                             unsigned long arg)
977 {
978         int err = 0;
979         void __user *argp = (void __user *)arg;
980
981         if (!capable(CAP_SYS_RESOURCE))
982                 return -EPERM;
983
984         switch (cmd) {
985         /* Attach an MTD device command */
986         case UBI_IOCATT:
987         {
988                 struct ubi_attach_req req;
989                 struct mtd_info *mtd;
990
991                 dbg_gen("attach MTD device");
992                 err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
993                 if (err) {
994                         err = -EFAULT;
995                         break;
996                 }
997
998                 if (req.mtd_num < 0 ||
999                     (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
1000                         err = -EINVAL;
1001                         break;
1002                 }
1003
1004                 mtd = get_mtd_device(NULL, req.mtd_num);
1005                 if (IS_ERR(mtd)) {
1006                         err = PTR_ERR(mtd);
1007                         break;
1008                 }
1009
1010                 /*
1011                  * Note, further request verification is done by
1012                  * 'ubi_attach_mtd_dev()'.
1013                  */
1014                 mutex_lock(&ubi_devices_mutex);
1015                 err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset,
1016                                          req.max_beb_per1024);
1017                 mutex_unlock(&ubi_devices_mutex);
1018                 if (err < 0)
1019                         put_mtd_device(mtd);
1020                 else
1021                         /* @err contains UBI device number */
1022                         err = put_user(err, (__user int32_t *)argp);
1023
1024                 break;
1025         }
1026
1027         /* Detach an MTD device command */
1028         case UBI_IOCDET:
1029         {
1030                 int ubi_num;
1031
1032                 dbg_gen("detach MTD device");
1033                 err = get_user(ubi_num, (__user int32_t *)argp);
1034                 if (err) {
1035                         err = -EFAULT;
1036                         break;
1037                 }
1038
1039                 mutex_lock(&ubi_devices_mutex);
1040                 err = ubi_detach_mtd_dev(ubi_num, 0);
1041                 mutex_unlock(&ubi_devices_mutex);
1042                 break;
1043         }
1044
1045         default:
1046                 err = -ENOTTY;
1047                 break;
1048         }
1049
1050         return err;
1051 }
1052
1053 #ifdef CONFIG_COMPAT
1054 static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1055                                   unsigned long arg)
1056 {
1057         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1058
1059         return vol_cdev_ioctl(file, cmd, translated_arg);
1060 }
1061
1062 static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1063                                   unsigned long arg)
1064 {
1065         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1066
1067         return ubi_cdev_ioctl(file, cmd, translated_arg);
1068 }
1069
1070 static long ctrl_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1071                                    unsigned long arg)
1072 {
1073         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1074
1075         return ctrl_cdev_ioctl(file, cmd, translated_arg);
1076 }
1077 #else
1078 #define vol_cdev_compat_ioctl  NULL
1079 #define ubi_cdev_compat_ioctl  NULL
1080 #define ctrl_cdev_compat_ioctl NULL
1081 #endif
1082
1083 /* UBI volume character device operations */
1084 const struct file_operations ubi_vol_cdev_operations = {
1085         .owner          = THIS_MODULE,
1086         .open           = vol_cdev_open,
1087         .release        = vol_cdev_release,
1088         .llseek         = vol_cdev_llseek,
1089         .read           = vol_cdev_read,
1090         .write          = vol_cdev_write,
1091         .fsync          = vol_cdev_fsync,
1092         .unlocked_ioctl = vol_cdev_ioctl,
1093         .compat_ioctl   = vol_cdev_compat_ioctl,
1094 };
1095
1096 /* UBI character device operations */
1097 const struct file_operations ubi_cdev_operations = {
1098         .owner          = THIS_MODULE,
1099         .llseek         = no_llseek,
1100         .unlocked_ioctl = ubi_cdev_ioctl,
1101         .compat_ioctl   = ubi_cdev_compat_ioctl,
1102 };
1103
1104 /* UBI control character device operations */
1105 const struct file_operations ubi_ctrl_cdev_operations = {
1106         .owner          = THIS_MODULE,
1107         .unlocked_ioctl = ctrl_cdev_ioctl,
1108         .compat_ioctl   = ctrl_cdev_compat_ioctl,
1109         .llseek         = no_llseek,
1110 };