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Linux 4.19.133
[linux/fpc-iii.git] / drivers / mtd / mtdswap.c
blobd9dcb2d051b4b0393f7a1c0a68769dfc29c52dda
1 /*
2 * Swap block device support for MTDs
3 * Turns an MTD device into a swap device with block wear leveling
4 *
5 * Copyright © 2007,2011 Nokia Corporation. All rights reserved.
6 *
7 * Authors: Jarkko Lavinen <jarkko.lavinen@nokia.com>
8 *
9 * Based on Richard Purdie's earlier implementation in 2007. Background
10 * support and lock-less operation written by Adrian Hunter.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * version 2 as published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful, but
17 * WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
24 * 02110-1301 USA
25 */
26
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/mtd/mtd.h>
30 #include <linux/mtd/blktrans.h>
31 #include <linux/rbtree.h>
32 #include <linux/sched.h>
33 #include <linux/slab.h>
34 #include <linux/vmalloc.h>
35 #include <linux/genhd.h>
36 #include <linux/swap.h>
37 #include <linux/debugfs.h>
38 #include <linux/seq_file.h>
39 #include <linux/device.h>
40 #include <linux/math64.h>
41
42 #define MTDSWAP_PREFIX "mtdswap"
43
44 /*
45 * The number of free eraseblocks when GC should stop
46 */
47 #define CLEAN_BLOCK_THRESHOLD 20
48
49 /*
50 * Number of free eraseblocks below which GC can also collect low frag
51 * blocks.
52 */
53 #define LOW_FRAG_GC_THRESHOLD 5
54
55 /*
56 * Wear level cost amortization. We want to do wear leveling on the background
57 * without disturbing gc too much. This is made by defining max GC frequency.
58 * Frequency value 6 means 1/6 of the GC passes will pick an erase block based
59 * on the biggest wear difference rather than the biggest dirtiness.
60 *
61 * The lower freq2 should be chosen so that it makes sure the maximum erase
62 * difference will decrease even if a malicious application is deliberately
63 * trying to make erase differences large.
64 */
65 #define MAX_ERASE_DIFF 4000
66 #define COLLECT_NONDIRTY_BASE MAX_ERASE_DIFF
67 #define COLLECT_NONDIRTY_FREQ1 6
68 #define COLLECT_NONDIRTY_FREQ2 4
69
70 #define PAGE_UNDEF UINT_MAX
71 #define BLOCK_UNDEF UINT_MAX
72 #define BLOCK_ERROR (UINT_MAX - 1)
73 #define BLOCK_MAX (UINT_MAX - 2)
74
75 #define EBLOCK_BAD (1 << 0)
76 #define EBLOCK_NOMAGIC (1 << 1)
77 #define EBLOCK_BITFLIP (1 << 2)
78 #define EBLOCK_FAILED (1 << 3)
79 #define EBLOCK_READERR (1 << 4)
80 #define EBLOCK_IDX_SHIFT 5
81
82 struct swap_eb {
83 struct rb_node rb;
84 struct rb_root *root;
85
86 unsigned int flags;
87 unsigned int active_count;
88 unsigned int erase_count;
89 unsigned int pad; /* speeds up pointer decrement */
90 };
91
92 #define MTDSWAP_ECNT_MIN(rbroot) (rb_entry(rb_first(rbroot), struct swap_eb, \
93 rb)->erase_count)
94 #define MTDSWAP_ECNT_MAX(rbroot) (rb_entry(rb_last(rbroot), struct swap_eb, \
95 rb)->erase_count)
96
97 struct mtdswap_tree {
98 struct rb_root root;
99 unsigned int count;
100 };
101
102 enum {
103 MTDSWAP_CLEAN,
104 MTDSWAP_USED,
105 MTDSWAP_LOWFRAG,
106 MTDSWAP_HIFRAG,
107 MTDSWAP_DIRTY,
108 MTDSWAP_BITFLIP,
109 MTDSWAP_FAILING,
110 MTDSWAP_TREE_CNT,
111 };
112
113 struct mtdswap_dev {
114 struct mtd_blktrans_dev *mbd_dev;
115 struct mtd_info *mtd;
116 struct device *dev;
117
118 unsigned int *page_data;
119 unsigned int *revmap;
120
121 unsigned int eblks;
122 unsigned int spare_eblks;
123 unsigned int pages_per_eblk;
124 unsigned int max_erase_count;
125 struct swap_eb *eb_data;
126
127 struct mtdswap_tree trees[MTDSWAP_TREE_CNT];
128
129 unsigned long long sect_read_count;
130 unsigned long long sect_write_count;
131 unsigned long long mtd_write_count;
132 unsigned long long mtd_read_count;
133 unsigned long long discard_count;
134 unsigned long long discard_page_count;
135
136 unsigned int curr_write_pos;
137 struct swap_eb *curr_write;
138
139 char *page_buf;
140 char *oob_buf;
141 };
142
143 struct mtdswap_oobdata {
144 __le16 magic;
145 __le32 count;
146 } __packed;
147
148 #define MTDSWAP_MAGIC_CLEAN 0x2095
149 #define MTDSWAP_MAGIC_DIRTY (MTDSWAP_MAGIC_CLEAN + 1)
150 #define MTDSWAP_TYPE_CLEAN 0
151 #define MTDSWAP_TYPE_DIRTY 1
152 #define MTDSWAP_OOBSIZE sizeof(struct mtdswap_oobdata)
153
154 #define MTDSWAP_ERASE_RETRIES 3 /* Before marking erase block bad */
155 #define MTDSWAP_IO_RETRIES 3
156
157 enum {
158 MTDSWAP_SCANNED_CLEAN,
159 MTDSWAP_SCANNED_DIRTY,
160 MTDSWAP_SCANNED_BITFLIP,
161 MTDSWAP_SCANNED_BAD,
162 };
163
164 /*
165 * In the worst case mtdswap_writesect() has allocated the last clean
166 * page from the current block and is then pre-empted by the GC
167 * thread. The thread can consume a full erase block when moving a
168 * block.
169 */
170 #define MIN_SPARE_EBLOCKS 2
171 #define MIN_ERASE_BLOCKS (MIN_SPARE_EBLOCKS + 1)
172
173 #define TREE_ROOT(d, name) (&d->trees[MTDSWAP_ ## name].root)
174 #define TREE_EMPTY(d, name) (TREE_ROOT(d, name)->rb_node == NULL)
175 #define TREE_NONEMPTY(d, name) (!TREE_EMPTY(d, name))
176 #define TREE_COUNT(d, name) (d->trees[MTDSWAP_ ## name].count)
177
178 #define MTDSWAP_MBD_TO_MTDSWAP(dev) ((struct mtdswap_dev *)dev->priv)
179
180 static char partitions[128] = "";
181 module_param_string(partitions, partitions, sizeof(partitions), 0444);
182 MODULE_PARM_DESC(partitions, "MTD partition numbers to use as swap "
183 "partitions=\"1,3,5\"");
184
185 static unsigned int spare_eblocks = 10;
186 module_param(spare_eblocks, uint, 0444);
187 MODULE_PARM_DESC(spare_eblocks, "Percentage of spare erase blocks for "
188 "garbage collection (default 10%)");
189
190 static bool header; /* false */
191 module_param(header, bool, 0444);
192 MODULE_PARM_DESC(header,
193 "Include builtin swap header (default 0, without header)");
194
195 static int mtdswap_gc(struct mtdswap_dev *d, unsigned int background);
196
197 static loff_t mtdswap_eb_offset(struct mtdswap_dev *d, struct swap_eb *eb)
198 {
199 return (loff_t)(eb - d->eb_data) * d->mtd->erasesize;
200 }
201
202 static void mtdswap_eb_detach(struct mtdswap_dev *d, struct swap_eb *eb)
203 {
204 unsigned int oldidx;
205 struct mtdswap_tree *tp;
206
207 if (eb->root) {
208 tp = container_of(eb->root, struct mtdswap_tree, root);
209 oldidx = tp - &d->trees[0];
210
211 d->trees[oldidx].count--;
212 rb_erase(&eb->rb, eb->root);
213 }
214 }
215
216 static void __mtdswap_rb_add(struct rb_root *root, struct swap_eb *eb)
217 {
218 struct rb_node **p, *parent = NULL;
219 struct swap_eb *cur;
220
221 p = &root->rb_node;
222 while (*p) {
223 parent = *p;
224 cur = rb_entry(parent, struct swap_eb, rb);
225 if (eb->erase_count > cur->erase_count)
226 p = &(*p)->rb_right;
227 else
228 p = &(*p)->rb_left;
229 }
230
231 rb_link_node(&eb->rb, parent, p);
232 rb_insert_color(&eb->rb, root);
233 }
234
235 static void mtdswap_rb_add(struct mtdswap_dev *d, struct swap_eb *eb, int idx)
236 {
237 struct rb_root *root;
238
239 if (eb->root == &d->trees[idx].root)
240 return;
241
242 mtdswap_eb_detach(d, eb);
243 root = &d->trees[idx].root;
244 __mtdswap_rb_add(root, eb);
245 eb->root = root;
246 d->trees[idx].count++;
247 }
248
249 static struct rb_node *mtdswap_rb_index(struct rb_root *root, unsigned int idx)
250 {
251 struct rb_node *p;
252 unsigned int i;
253
254 p = rb_first(root);
255 i = 0;
256 while (i < idx && p) {
257 p = rb_next(p);
258 i++;
259 }
260
261 return p;
262 }
263
264 static int mtdswap_handle_badblock(struct mtdswap_dev *d, struct swap_eb *eb)
265 {
266 int ret;
267 loff_t offset;
268
269 d->spare_eblks--;
270 eb->flags |= EBLOCK_BAD;
271 mtdswap_eb_detach(d, eb);
272 eb->root = NULL;
273
274 /* badblocks not supported */
275 if (!mtd_can_have_bb(d->mtd))
276 return 1;
277
278 offset = mtdswap_eb_offset(d, eb);
279 dev_warn(d->dev, "Marking bad block at %08llx\n", offset);
280 ret = mtd_block_markbad(d->mtd, offset);
281
282 if (ret) {
283 dev_warn(d->dev, "Mark block bad failed for block at %08llx "
284 "error %d\n", offset, ret);
285 return ret;
286 }
287
288 return 1;
289
290 }
291
292 static int mtdswap_handle_write_error(struct mtdswap_dev *d, struct swap_eb *eb)
293 {
294 unsigned int marked = eb->flags & EBLOCK_FAILED;
295 struct swap_eb *curr_write = d->curr_write;
296
297 eb->flags |= EBLOCK_FAILED;
298 if (curr_write == eb) {
299 d->curr_write = NULL;
300
301 if (!marked && d->curr_write_pos != 0) {
302 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
303 return 0;
304 }
305 }
306
307 return mtdswap_handle_badblock(d, eb);
308 }
309
310 static int mtdswap_read_oob(struct mtdswap_dev *d, loff_t from,
311 struct mtd_oob_ops *ops)
312 {
313 int ret = mtd_read_oob(d->mtd, from, ops);
314
315 if (mtd_is_bitflip(ret))
316 return ret;
317
318 if (ret) {
319 dev_warn(d->dev, "Read OOB failed %d for block at %08llx\n",
320 ret, from);
321 return ret;
322 }
323
324 if (ops->oobretlen < ops->ooblen) {
325 dev_warn(d->dev, "Read OOB return short read (%zd bytes not "
326 "%zd) for block at %08llx\n",
327 ops->oobretlen, ops->ooblen, from);
328 return -EIO;
329 }
330
331 return 0;
332 }
333
334 static int mtdswap_read_markers(struct mtdswap_dev *d, struct swap_eb *eb)
335 {
336 struct mtdswap_oobdata *data, *data2;
337 int ret;
338 loff_t offset;
339 struct mtd_oob_ops ops;
340
341 offset = mtdswap_eb_offset(d, eb);
342
343 /* Check first if the block is bad. */
344 if (mtd_can_have_bb(d->mtd) && mtd_block_isbad(d->mtd, offset))
345 return MTDSWAP_SCANNED_BAD;
346
347 ops.ooblen = 2 * d->mtd->oobavail;
348 ops.oobbuf = d->oob_buf;
349 ops.ooboffs = 0;
350 ops.datbuf = NULL;
351 ops.mode = MTD_OPS_AUTO_OOB;
352
353 ret = mtdswap_read_oob(d, offset, &ops);
354
355 if (ret && !mtd_is_bitflip(ret))
356 return ret;
357
358 data = (struct mtdswap_oobdata *)d->oob_buf;
359 data2 = (struct mtdswap_oobdata *)
360 (d->oob_buf + d->mtd->oobavail);
361
362 if (le16_to_cpu(data->magic) == MTDSWAP_MAGIC_CLEAN) {
363 eb->erase_count = le32_to_cpu(data->count);
364 if (mtd_is_bitflip(ret))
365 ret = MTDSWAP_SCANNED_BITFLIP;
366 else {
367 if (le16_to_cpu(data2->magic) == MTDSWAP_MAGIC_DIRTY)
368 ret = MTDSWAP_SCANNED_DIRTY;
369 else
370 ret = MTDSWAP_SCANNED_CLEAN;
371 }
372 } else {
373 eb->flags |= EBLOCK_NOMAGIC;
374 ret = MTDSWAP_SCANNED_DIRTY;
375 }
376
377 return ret;
378 }
379
380 static int mtdswap_write_marker(struct mtdswap_dev *d, struct swap_eb *eb,
381 u16 marker)
382 {
383 struct mtdswap_oobdata n;
384 int ret;
385 loff_t offset;
386 struct mtd_oob_ops ops;
387
388 ops.ooboffs = 0;
389 ops.oobbuf = (uint8_t *)&n;
390 ops.mode = MTD_OPS_AUTO_OOB;
391 ops.datbuf = NULL;
392
393 if (marker == MTDSWAP_TYPE_CLEAN) {
394 n.magic = cpu_to_le16(MTDSWAP_MAGIC_CLEAN);
395 n.count = cpu_to_le32(eb->erase_count);
396 ops.ooblen = MTDSWAP_OOBSIZE;
397 offset = mtdswap_eb_offset(d, eb);
398 } else {
399 n.magic = cpu_to_le16(MTDSWAP_MAGIC_DIRTY);
400 ops.ooblen = sizeof(n.magic);
401 offset = mtdswap_eb_offset(d, eb) + d->mtd->writesize;
402 }
403
404 ret = mtd_write_oob(d->mtd, offset, &ops);
405
406 if (ret) {
407 dev_warn(d->dev, "Write OOB failed for block at %08llx "
408 "error %d\n", offset, ret);
409 if (ret == -EIO || mtd_is_eccerr(ret))
410 mtdswap_handle_write_error(d, eb);
411 return ret;
412 }
413
414 if (ops.oobretlen != ops.ooblen) {
415 dev_warn(d->dev, "Short OOB write for block at %08llx: "
416 "%zd not %zd\n",
417 offset, ops.oobretlen, ops.ooblen);
418 return ret;
419 }
420
421 return 0;
422 }
423
424 /*
425 * Are there any erase blocks without MAGIC_CLEAN header, presumably
426 * because power was cut off after erase but before header write? We
427 * need to guestimate the erase count.
428 */
429 static void mtdswap_check_counts(struct mtdswap_dev *d)
430 {
431 struct rb_root hist_root = RB_ROOT;
432 struct rb_node *medrb;
433 struct swap_eb *eb;
434 unsigned int i, cnt, median;
435
436 cnt = 0;
437 for (i = 0; i < d->eblks; i++) {
438 eb = d->eb_data + i;
439
440 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_BAD | EBLOCK_READERR))
441 continue;
442
443 __mtdswap_rb_add(&hist_root, eb);
444 cnt++;
445 }
446
447 if (cnt == 0)
448 return;
449
450 medrb = mtdswap_rb_index(&hist_root, cnt / 2);
451 median = rb_entry(medrb, struct swap_eb, rb)->erase_count;
452
453 d->max_erase_count = MTDSWAP_ECNT_MAX(&hist_root);
454
455 for (i = 0; i < d->eblks; i++) {
456 eb = d->eb_data + i;
457
458 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_READERR))
459 eb->erase_count = median;
460
461 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_BAD | EBLOCK_READERR))
462 continue;
463
464 rb_erase(&eb->rb, &hist_root);
465 }
466 }
467
468 static void mtdswap_scan_eblks(struct mtdswap_dev *d)
469 {
470 int status;
471 unsigned int i, idx;
472 struct swap_eb *eb;
473
474 for (i = 0; i < d->eblks; i++) {
475 eb = d->eb_data + i;
476
477 status = mtdswap_read_markers(d, eb);
478 if (status < 0)
479 eb->flags |= EBLOCK_READERR;
480 else if (status == MTDSWAP_SCANNED_BAD) {
481 eb->flags |= EBLOCK_BAD;
482 continue;
483 }
484
485 switch (status) {
486 case MTDSWAP_SCANNED_CLEAN:
487 idx = MTDSWAP_CLEAN;
488 break;
489 case MTDSWAP_SCANNED_DIRTY:
490 case MTDSWAP_SCANNED_BITFLIP:
491 idx = MTDSWAP_DIRTY;
492 break;
493 default:
494 idx = MTDSWAP_FAILING;
495 }
496
497 eb->flags |= (idx << EBLOCK_IDX_SHIFT);
498 }
499
500 mtdswap_check_counts(d);
501
502 for (i = 0; i < d->eblks; i++) {
503 eb = d->eb_data + i;
504
505 if (eb->flags & EBLOCK_BAD)
506 continue;
507
508 idx = eb->flags >> EBLOCK_IDX_SHIFT;
509 mtdswap_rb_add(d, eb, idx);
510 }
511 }
512
513 /*
514 * Place eblk into a tree corresponding to its number of active blocks
515 * it contains.
516 */
517 static void mtdswap_store_eb(struct mtdswap_dev *d, struct swap_eb *eb)
518 {
519 unsigned int weight = eb->active_count;
520 unsigned int maxweight = d->pages_per_eblk;
521
522 if (eb == d->curr_write)
523 return;
524
525 if (eb->flags & EBLOCK_BITFLIP)
526 mtdswap_rb_add(d, eb, MTDSWAP_BITFLIP);
527 else if (eb->flags & (EBLOCK_READERR | EBLOCK_FAILED))
528 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
529 if (weight == maxweight)
530 mtdswap_rb_add(d, eb, MTDSWAP_USED);
531 else if (weight == 0)
532 mtdswap_rb_add(d, eb, MTDSWAP_DIRTY);
533 else if (weight > (maxweight/2))
534 mtdswap_rb_add(d, eb, MTDSWAP_LOWFRAG);
535 else
536 mtdswap_rb_add(d, eb, MTDSWAP_HIFRAG);
537 }
538
539 static int mtdswap_erase_block(struct mtdswap_dev *d, struct swap_eb *eb)
540 {
541 struct mtd_info *mtd = d->mtd;
542 struct erase_info erase;
543 unsigned int retries = 0;
544 int ret;
545
546 eb->erase_count++;
547 if (eb->erase_count > d->max_erase_count)
548 d->max_erase_count = eb->erase_count;
549
550 retry:
551 memset(&erase, 0, sizeof(struct erase_info));
552 erase.addr = mtdswap_eb_offset(d, eb);
553 erase.len = mtd->erasesize;
554
555 ret = mtd_erase(mtd, &erase);
556 if (ret) {
557 if (retries++ < MTDSWAP_ERASE_RETRIES) {
558 dev_warn(d->dev,
559 "erase of erase block %#llx on %s failed",
560 erase.addr, mtd->name);
561 yield();
562 goto retry;
563 }
564
565 dev_err(d->dev, "Cannot erase erase block %#llx on %s\n",
566 erase.addr, mtd->name);
567
568 mtdswap_handle_badblock(d, eb);
569 return -EIO;
570 }
571
572 return 0;
573 }
574
575 static int mtdswap_map_free_block(struct mtdswap_dev *d, unsigned int page,
576 unsigned int *block)
577 {
578 int ret;
579 struct swap_eb *old_eb = d->curr_write;
580 struct rb_root *clean_root;
581 struct swap_eb *eb;
582
583 if (old_eb == NULL || d->curr_write_pos >= d->pages_per_eblk) {
584 do {
585 if (TREE_EMPTY(d, CLEAN))
586 return -ENOSPC;
587
588 clean_root = TREE_ROOT(d, CLEAN);
589 eb = rb_entry(rb_first(clean_root), struct swap_eb, rb);
590 rb_erase(&eb->rb, clean_root);
591 eb->root = NULL;
592 TREE_COUNT(d, CLEAN)--;
593
594 ret = mtdswap_write_marker(d, eb, MTDSWAP_TYPE_DIRTY);
595 } while (ret == -EIO || mtd_is_eccerr(ret));
596
597 if (ret)
598 return ret;
599
600 d->curr_write_pos = 0;
601 d->curr_write = eb;
602 if (old_eb)
603 mtdswap_store_eb(d, old_eb);
604 }
605
606 *block = (d->curr_write - d->eb_data) * d->pages_per_eblk +
607 d->curr_write_pos;
608
609 d->curr_write->active_count++;
610 d->revmap[*block] = page;
611 d->curr_write_pos++;
612
613 return 0;
614 }
615
616 static unsigned int mtdswap_free_page_cnt(struct mtdswap_dev *d)
617 {
618 return TREE_COUNT(d, CLEAN) * d->pages_per_eblk +
619 d->pages_per_eblk - d->curr_write_pos;
620 }
621
622 static unsigned int mtdswap_enough_free_pages(struct mtdswap_dev *d)
623 {
624 return mtdswap_free_page_cnt(d) > d->pages_per_eblk;
625 }
626
627 static int mtdswap_write_block(struct mtdswap_dev *d, char *buf,
628 unsigned int page, unsigned int *bp, int gc_context)
629 {
630 struct mtd_info *mtd = d->mtd;
631 struct swap_eb *eb;
632 size_t retlen;
633 loff_t writepos;
634 int ret;
635
636 retry:
637 if (!gc_context)
638 while (!mtdswap_enough_free_pages(d))
639 if (mtdswap_gc(d, 0) > 0)
640 return -ENOSPC;
641
642 ret = mtdswap_map_free_block(d, page, bp);
643 eb = d->eb_data + (*bp / d->pages_per_eblk);
644
645 if (ret == -EIO || mtd_is_eccerr(ret)) {
646 d->curr_write = NULL;
647 eb->active_count--;
648 d->revmap[*bp] = PAGE_UNDEF;
649 goto retry;
650 }
651
652 if (ret < 0)
653 return ret;
654
655 writepos = (loff_t)*bp << PAGE_SHIFT;
656 ret = mtd_write(mtd, writepos, PAGE_SIZE, &retlen, buf);
657 if (ret == -EIO || mtd_is_eccerr(ret)) {
658 d->curr_write_pos--;
659 eb->active_count--;
660 d->revmap[*bp] = PAGE_UNDEF;
661 mtdswap_handle_write_error(d, eb);
662 goto retry;
663 }
664
665 if (ret < 0) {
666 dev_err(d->dev, "Write to MTD device failed: %d (%zd written)",
667 ret, retlen);
668 goto err;
669 }
670
671 if (retlen != PAGE_SIZE) {
672 dev_err(d->dev, "Short write to MTD device: %zd written",
673 retlen);
674 ret = -EIO;
675 goto err;
676 }
677
678 return ret;
679
680 err:
681 d->curr_write_pos--;
682 eb->active_count--;
683 d->revmap[*bp] = PAGE_UNDEF;
684
685 return ret;
686 }
687
688 static int mtdswap_move_block(struct mtdswap_dev *d, unsigned int oldblock,
689 unsigned int *newblock)
690 {
691 struct mtd_info *mtd = d->mtd;
692 struct swap_eb *eb, *oldeb;
693 int ret;
694 size_t retlen;
695 unsigned int page, retries;
696 loff_t readpos;
697
698 page = d->revmap[oldblock];
699 readpos = (loff_t) oldblock << PAGE_SHIFT;
700 retries = 0;
701
702 retry:
703 ret = mtd_read(mtd, readpos, PAGE_SIZE, &retlen, d->page_buf);
704
705 if (ret < 0 && !mtd_is_bitflip(ret)) {
706 oldeb = d->eb_data + oldblock / d->pages_per_eblk;
707 oldeb->flags |= EBLOCK_READERR;
708
709 dev_err(d->dev, "Read Error: %d (block %u)\n", ret,
710 oldblock);
711 retries++;
712 if (retries < MTDSWAP_IO_RETRIES)
713 goto retry;
714
715 goto read_error;
716 }
717
718 if (retlen != PAGE_SIZE) {
719 dev_err(d->dev, "Short read: %zd (block %u)\n", retlen,
720 oldblock);
721 ret = -EIO;
722 goto read_error;
723 }
724
725 ret = mtdswap_write_block(d, d->page_buf, page, newblock, 1);
726 if (ret < 0) {
727 d->page_data[page] = BLOCK_ERROR;
728 dev_err(d->dev, "Write error: %d\n", ret);
729 return ret;
730 }
731
732 eb = d->eb_data + *newblock / d->pages_per_eblk;
733 d->page_data[page] = *newblock;
734 d->revmap[oldblock] = PAGE_UNDEF;
735 eb = d->eb_data + oldblock / d->pages_per_eblk;
736 eb->active_count--;
737
738 return 0;
739
740 read_error:
741 d->page_data[page] = BLOCK_ERROR;
742 d->revmap[oldblock] = PAGE_UNDEF;
743 return ret;
744 }
745
746 static int mtdswap_gc_eblock(struct mtdswap_dev *d, struct swap_eb *eb)
747 {
748 unsigned int i, block, eblk_base, newblock;
749 int ret, errcode;
750
751 errcode = 0;
752 eblk_base = (eb - d->eb_data) * d->pages_per_eblk;
753
754 for (i = 0; i < d->pages_per_eblk; i++) {
755 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
756 return -ENOSPC;
757
758 block = eblk_base + i;
759 if (d->revmap[block] == PAGE_UNDEF)
760 continue;
761
762 ret = mtdswap_move_block(d, block, &newblock);
763 if (ret < 0 && !errcode)
764 errcode = ret;
765 }
766
767 return errcode;
768 }
769
770 static int __mtdswap_choose_gc_tree(struct mtdswap_dev *d)
771 {
772 int idx, stopat;
773
774 if (TREE_COUNT(d, CLEAN) < LOW_FRAG_GC_THRESHOLD)
775 stopat = MTDSWAP_LOWFRAG;
776 else
777 stopat = MTDSWAP_HIFRAG;
778
779 for (idx = MTDSWAP_BITFLIP; idx >= stopat; idx--)
780 if (d->trees[idx].root.rb_node != NULL)
781 return idx;
782
783 return -1;
784 }
785
786 static int mtdswap_wlfreq(unsigned int maxdiff)
787 {
788 unsigned int h, x, y, dist, base;
789
790 /*
791 * Calculate linear ramp down from f1 to f2 when maxdiff goes from
792 * MAX_ERASE_DIFF to MAX_ERASE_DIFF + COLLECT_NONDIRTY_BASE. Similar
793 * to triangle with height f1 - f1 and width COLLECT_NONDIRTY_BASE.
794 */
795
796 dist = maxdiff - MAX_ERASE_DIFF;
797 if (dist > COLLECT_NONDIRTY_BASE)
798 dist = COLLECT_NONDIRTY_BASE;
799
800 /*
801 * Modelling the slop as right angular triangle with base
802 * COLLECT_NONDIRTY_BASE and height freq1 - freq2. The ratio y/x is
803 * equal to the ratio h/base.
804 */
805 h = COLLECT_NONDIRTY_FREQ1 - COLLECT_NONDIRTY_FREQ2;
806 base = COLLECT_NONDIRTY_BASE;
807
808 x = dist - base;
809 y = (x * h + base / 2) / base;
810
811 return COLLECT_NONDIRTY_FREQ2 + y;
812 }
813
814 static int mtdswap_choose_wl_tree(struct mtdswap_dev *d)
815 {
816 static unsigned int pick_cnt;
817 unsigned int i, idx = -1, wear, max;
818 struct rb_root *root;
819
820 max = 0;
821 for (i = 0; i <= MTDSWAP_DIRTY; i++) {
822 root = &d->trees[i].root;
823 if (root->rb_node == NULL)
824 continue;
825
826 wear = d->max_erase_count - MTDSWAP_ECNT_MIN(root);
827 if (wear > max) {
828 max = wear;
829 idx = i;
830 }
831 }
832
833 if (max > MAX_ERASE_DIFF && pick_cnt >= mtdswap_wlfreq(max) - 1) {
834 pick_cnt = 0;
835 return idx;
836 }
837
838 pick_cnt++;
839 return -1;
840 }
841
842 static int mtdswap_choose_gc_tree(struct mtdswap_dev *d,
843 unsigned int background)
844 {
845 int idx;
846
847 if (TREE_NONEMPTY(d, FAILING) &&
848 (background || (TREE_EMPTY(d, CLEAN) && TREE_EMPTY(d, DIRTY))))
849 return MTDSWAP_FAILING;
850
851 idx = mtdswap_choose_wl_tree(d);
852 if (idx >= MTDSWAP_CLEAN)
853 return idx;
854
855 return __mtdswap_choose_gc_tree(d);
856 }
857
858 static struct swap_eb *mtdswap_pick_gc_eblk(struct mtdswap_dev *d,
859 unsigned int background)
860 {
861 struct rb_root *rp = NULL;
862 struct swap_eb *eb = NULL;
863 int idx;
864
865 if (background && TREE_COUNT(d, CLEAN) > CLEAN_BLOCK_THRESHOLD &&
866 TREE_EMPTY(d, DIRTY) && TREE_EMPTY(d, FAILING))
867 return NULL;
868
869 idx = mtdswap_choose_gc_tree(d, background);
870 if (idx < 0)
871 return NULL;
872
873 rp = &d->trees[idx].root;
874 eb = rb_entry(rb_first(rp), struct swap_eb, rb);
875
876 rb_erase(&eb->rb, rp);
877 eb->root = NULL;
878 d->trees[idx].count--;
879 return eb;
880 }
881
882 static unsigned int mtdswap_test_patt(unsigned int i)
883 {
884 return i % 2 ? 0x55555555 : 0xAAAAAAAA;
885 }
886
887 static unsigned int mtdswap_eblk_passes(struct mtdswap_dev *d,
888 struct swap_eb *eb)
889 {
890 struct mtd_info *mtd = d->mtd;
891 unsigned int test, i, j, patt, mtd_pages;
892 loff_t base, pos;
893 unsigned int *p1 = (unsigned int *)d->page_buf;
894 unsigned char *p2 = (unsigned char *)d->oob_buf;
895 struct mtd_oob_ops ops;
896 int ret;
897
898 ops.mode = MTD_OPS_AUTO_OOB;
899 ops.len = mtd->writesize;
900 ops.ooblen = mtd->oobavail;
901 ops.ooboffs = 0;
902 ops.datbuf = d->page_buf;
903 ops.oobbuf = d->oob_buf;
904 base = mtdswap_eb_offset(d, eb);
905 mtd_pages = d->pages_per_eblk * PAGE_SIZE / mtd->writesize;
906
907 for (test = 0; test < 2; test++) {
908 pos = base;
909 for (i = 0; i < mtd_pages; i++) {
910 patt = mtdswap_test_patt(test + i);
911 memset(d->page_buf, patt, mtd->writesize);
912 memset(d->oob_buf, patt, mtd->oobavail);
913 ret = mtd_write_oob(mtd, pos, &ops);
914 if (ret)
915 goto error;
916
917 pos += mtd->writesize;
918 }
919
920 pos = base;
921 for (i = 0; i < mtd_pages; i++) {
922 ret = mtd_read_oob(mtd, pos, &ops);
923 if (ret)
924 goto error;
925
926 patt = mtdswap_test_patt(test + i);
927 for (j = 0; j < mtd->writesize/sizeof(int); j++)
928 if (p1[j] != patt)
929 goto error;
930
931 for (j = 0; j < mtd->oobavail; j++)
932 if (p2[j] != (unsigned char)patt)
933 goto error;
934
935 pos += mtd->writesize;
936 }
937
938 ret = mtdswap_erase_block(d, eb);
939 if (ret)
940 goto error;
941 }
942
943 eb->flags &= ~EBLOCK_READERR;
944 return 1;
945
946 error:
947 mtdswap_handle_badblock(d, eb);
948 return 0;
949 }
950
951 static int mtdswap_gc(struct mtdswap_dev *d, unsigned int background)
952 {
953 struct swap_eb *eb;
954 int ret;
955
956 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
957 return 1;
958
959 eb = mtdswap_pick_gc_eblk(d, background);
960 if (!eb)
961 return 1;
962
963 ret = mtdswap_gc_eblock(d, eb);
964 if (ret == -ENOSPC)
965 return 1;
966
967 if (eb->flags & EBLOCK_FAILED) {
968 mtdswap_handle_badblock(d, eb);
969 return 0;
970 }
971
972 eb->flags &= ~EBLOCK_BITFLIP;
973 ret = mtdswap_erase_block(d, eb);
974 if ((eb->flags & EBLOCK_READERR) &&
975 (ret || !mtdswap_eblk_passes(d, eb)))
976 return 0;
977
978 if (ret == 0)
979 ret = mtdswap_write_marker(d, eb, MTDSWAP_TYPE_CLEAN);
980
981 if (ret == 0)
982 mtdswap_rb_add(d, eb, MTDSWAP_CLEAN);
983 else if (ret != -EIO && !mtd_is_eccerr(ret))
984 mtdswap_rb_add(d, eb, MTDSWAP_DIRTY);
985
986 return 0;
987 }
988
989 static void mtdswap_background(struct mtd_blktrans_dev *dev)
990 {
991 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
992 int ret;
993
994 while (1) {
995 ret = mtdswap_gc(d, 1);
996 if (ret || mtd_blktrans_cease_background(dev))
997 return;
998 }
999 }
1000
1001 static void mtdswap_cleanup(struct mtdswap_dev *d)
1002 {
1003 vfree(d->eb_data);
1004 vfree(d->revmap);
1005 vfree(d->page_data);
1006 kfree(d->oob_buf);
1007 kfree(d->page_buf);
1008 }
1009
1010 static int mtdswap_flush(struct mtd_blktrans_dev *dev)
1011 {
1012 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1013
1014 mtd_sync(d->mtd);
1015 return 0;
1016 }
1017
1018 static unsigned int mtdswap_badblocks(struct mtd_info *mtd, uint64_t size)
1019 {
1020 loff_t offset;
1021 unsigned int badcnt;
1022
1023 badcnt = 0;
1024
1025 if (mtd_can_have_bb(mtd))
1026 for (offset = 0; offset < size; offset += mtd->erasesize)
1027 if (mtd_block_isbad(mtd, offset))
1028 badcnt++;
1029
1030 return badcnt;
1031 }
1032
1033 static int mtdswap_writesect(struct mtd_blktrans_dev *dev,
1034 unsigned long page, char *buf)
1035 {
1036 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1037 unsigned int newblock, mapped;
1038 struct swap_eb *eb;
1039 int ret;
1040
1041 d->sect_write_count++;
1042
1043 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
1044 return -ENOSPC;
1045
1046 if (header) {
1047 /* Ignore writes to the header page */
1048 if (unlikely(page == 0))
1049 return 0;
1050
1051 page--;
1052 }
1053
1054 mapped = d->page_data[page];
1055 if (mapped <= BLOCK_MAX) {
1056 eb = d->eb_data + (mapped / d->pages_per_eblk);
1057 eb->active_count--;
1058 mtdswap_store_eb(d, eb);
1059 d->page_data[page] = BLOCK_UNDEF;
1060 d->revmap[mapped] = PAGE_UNDEF;
1061 }
1062
1063 ret = mtdswap_write_block(d, buf, page, &newblock, 0);
1064 d->mtd_write_count++;
1065
1066 if (ret < 0)
1067 return ret;
1068
1069 eb = d->eb_data + (newblock / d->pages_per_eblk);
1070 d->page_data[page] = newblock;
1071
1072 return 0;
1073 }
1074
1075 /* Provide a dummy swap header for the kernel */
1076 static int mtdswap_auto_header(struct mtdswap_dev *d, char *buf)
1077 {
1078 union swap_header *hd = (union swap_header *)(buf);
1079
1080 memset(buf, 0, PAGE_SIZE - 10);
1081
1082 hd->info.version = 1;
1083 hd->info.last_page = d->mbd_dev->size - 1;
1084 hd->info.nr_badpages = 0;
1085
1086 memcpy(buf + PAGE_SIZE - 10, "SWAPSPACE2", 10);
1087
1088 return 0;
1089 }
1090
1091 static int mtdswap_readsect(struct mtd_blktrans_dev *dev,
1092 unsigned long page, char *buf)
1093 {
1094 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1095 struct mtd_info *mtd = d->mtd;
1096 unsigned int realblock, retries;
1097 loff_t readpos;
1098 struct swap_eb *eb;
1099 size_t retlen;
1100 int ret;
1101
1102 d->sect_read_count++;
1103
1104 if (header) {
1105 if (unlikely(page == 0))
1106 return mtdswap_auto_header(d, buf);
1107
1108 page--;
1109 }
1110
1111 realblock = d->page_data[page];
1112 if (realblock > BLOCK_MAX) {
1113 memset(buf, 0x0, PAGE_SIZE);
1114 if (realblock == BLOCK_UNDEF)
1115 return 0;
1116 else
1117 return -EIO;
1118 }
1119
1120 eb = d->eb_data + (realblock / d->pages_per_eblk);
1121 BUG_ON(d->revmap[realblock] == PAGE_UNDEF);
1122
1123 readpos = (loff_t)realblock << PAGE_SHIFT;
1124 retries = 0;
1125
1126 retry:
1127 ret = mtd_read(mtd, readpos, PAGE_SIZE, &retlen, buf);
1128
1129 d->mtd_read_count++;
1130 if (mtd_is_bitflip(ret)) {
1131 eb->flags |= EBLOCK_BITFLIP;
1132 mtdswap_rb_add(d, eb, MTDSWAP_BITFLIP);
1133 ret = 0;
1134 }
1135
1136 if (ret < 0) {
1137 dev_err(d->dev, "Read error %d\n", ret);
1138 eb->flags |= EBLOCK_READERR;
1139 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
1140 retries++;
1141 if (retries < MTDSWAP_IO_RETRIES)
1142 goto retry;
1143
1144 return ret;
1145 }
1146
1147 if (retlen != PAGE_SIZE) {
1148 dev_err(d->dev, "Short read %zd\n", retlen);
1149 return -EIO;
1150 }
1151
1152 return 0;
1153 }
1154
1155 static int mtdswap_discard(struct mtd_blktrans_dev *dev, unsigned long first,
1156 unsigned nr_pages)
1157 {
1158 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1159 unsigned long page;
1160 struct swap_eb *eb;
1161 unsigned int mapped;
1162
1163 d->discard_count++;
1164
1165 for (page = first; page < first + nr_pages; page++) {
1166 mapped = d->page_data[page];
1167 if (mapped <= BLOCK_MAX) {
1168 eb = d->eb_data + (mapped / d->pages_per_eblk);
1169 eb->active_count--;
1170 mtdswap_store_eb(d, eb);
1171 d->page_data[page] = BLOCK_UNDEF;
1172 d->revmap[mapped] = PAGE_UNDEF;
1173 d->discard_page_count++;
1174 } else if (mapped == BLOCK_ERROR) {
1175 d->page_data[page] = BLOCK_UNDEF;
1176 d->discard_page_count++;
1177 }
1178 }
1179
1180 return 0;
1181 }
1182
1183 static int mtdswap_show(struct seq_file *s, void *data)
1184 {
1185 struct mtdswap_dev *d = (struct mtdswap_dev *) s->private;
1186 unsigned long sum;
1187 unsigned int count[MTDSWAP_TREE_CNT];
1188 unsigned int min[MTDSWAP_TREE_CNT];
1189 unsigned int max[MTDSWAP_TREE_CNT];
1190 unsigned int i, cw = 0, cwp = 0, cwecount = 0, bb_cnt, mapped, pages;
1191 uint64_t use_size;
1192 static const char * const name[] = {
1193 "clean", "used", "low", "high", "dirty", "bitflip", "failing"
1194 };
1195
1196 mutex_lock(&d->mbd_dev->lock);
1197
1198 for (i = 0; i < MTDSWAP_TREE_CNT; i++) {
1199 struct rb_root *root = &d->trees[i].root;
1200
1201 if (root->rb_node) {
1202 count[i] = d->trees[i].count;
1203 min[i] = MTDSWAP_ECNT_MIN(root);
1204 max[i] = MTDSWAP_ECNT_MAX(root);
1205 } else
1206 count[i] = 0;
1207 }
1208
1209 if (d->curr_write) {
1210 cw = 1;
1211 cwp = d->curr_write_pos;
1212 cwecount = d->curr_write->erase_count;
1213 }
1214
1215 sum = 0;
1216 for (i = 0; i < d->eblks; i++)
1217 sum += d->eb_data[i].erase_count;
1218
1219 use_size = (uint64_t)d->eblks * d->mtd->erasesize;
1220 bb_cnt = mtdswap_badblocks(d->mtd, use_size);
1221
1222 mapped = 0;
1223 pages = d->mbd_dev->size;
1224 for (i = 0; i < pages; i++)
1225 if (d->page_data[i] != BLOCK_UNDEF)
1226 mapped++;
1227
1228 mutex_unlock(&d->mbd_dev->lock);
1229
1230 for (i = 0; i < MTDSWAP_TREE_CNT; i++) {
1231 if (!count[i])
1232 continue;
1233
1234 if (min[i] != max[i])
1235 seq_printf(s, "%s:\t%5d erase blocks, erased min %d, "
1236 "max %d times\n",
1237 name[i], count[i], min[i], max[i]);
1238 else
1239 seq_printf(s, "%s:\t%5d erase blocks, all erased %d "
1240 "times\n", name[i], count[i], min[i]);
1241 }
1242
1243 if (bb_cnt)
1244 seq_printf(s, "bad:\t%5u erase blocks\n", bb_cnt);
1245
1246 if (cw)
1247 seq_printf(s, "current erase block: %u pages used, %u free, "
1248 "erased %u times\n",
1249 cwp, d->pages_per_eblk - cwp, cwecount);
1250
1251 seq_printf(s, "total erasures: %lu\n", sum);
1252
1253 seq_puts(s, "\n");
1254
1255 seq_printf(s, "mtdswap_readsect count: %llu\n", d->sect_read_count);
1256 seq_printf(s, "mtdswap_writesect count: %llu\n", d->sect_write_count);
1257 seq_printf(s, "mtdswap_discard count: %llu\n", d->discard_count);
1258 seq_printf(s, "mtd read count: %llu\n", d->mtd_read_count);
1259 seq_printf(s, "mtd write count: %llu\n", d->mtd_write_count);
1260 seq_printf(s, "discarded pages count: %llu\n", d->discard_page_count);
1261
1262 seq_puts(s, "\n");
1263 seq_printf(s, "total pages: %u\n", pages);
1264 seq_printf(s, "pages mapped: %u\n", mapped);
1265
1266 return 0;
1267 }
1268
1269 static int mtdswap_open(struct inode *inode, struct file *file)
1270 {
1271 return single_open(file, mtdswap_show, inode->i_private);
1272 }
1273
1274 static const struct file_operations mtdswap_fops = {
1275 .open = mtdswap_open,
1276 .read = seq_read,
1277 .llseek = seq_lseek,
1278 .release = single_release,
1279 };
1280
1281 static int mtdswap_add_debugfs(struct mtdswap_dev *d)
1282 {
1283 struct dentry *root = d->mtd->dbg.dfs_dir;
1284 struct dentry *dent;
1285
1286 if (!IS_ENABLED(CONFIG_DEBUG_FS))
1287 return 0;
1288
1289 if (IS_ERR_OR_NULL(root))
1290 return -1;
1291
1292 dent = debugfs_create_file("mtdswap_stats", S_IRUSR, root, d,
1293 &mtdswap_fops);
1294 if (!dent) {
1295 dev_err(d->dev, "debugfs_create_file failed\n");
1296 return -1;
1297 }
1298
1299 return 0;
1300 }
1301
1302 static int mtdswap_init(struct mtdswap_dev *d, unsigned int eblocks,
1303 unsigned int spare_cnt)
1304 {
1305 struct mtd_info *mtd = d->mbd_dev->mtd;
1306 unsigned int i, eblk_bytes, pages, blocks;
1307 int ret = -ENOMEM;
1308
1309 d->mtd = mtd;
1310 d->eblks = eblocks;
1311 d->spare_eblks = spare_cnt;
1312 d->pages_per_eblk = mtd->erasesize >> PAGE_SHIFT;
1313
1314 pages = d->mbd_dev->size;
1315 blocks = eblocks * d->pages_per_eblk;
1316
1317 for (i = 0; i < MTDSWAP_TREE_CNT; i++)
1318 d->trees[i].root = RB_ROOT;
1319
1320 d->page_data = vmalloc(array_size(pages, sizeof(int)));
1321 if (!d->page_data)
1322 goto page_data_fail;
1323
1324 d->revmap = vmalloc(array_size(blocks, sizeof(int)));
1325 if (!d->revmap)
1326 goto revmap_fail;
1327
1328 eblk_bytes = sizeof(struct swap_eb)*d->eblks;
1329 d->eb_data = vzalloc(eblk_bytes);
1330 if (!d->eb_data)
1331 goto eb_data_fail;
1332
1333 for (i = 0; i < pages; i++)
1334 d->page_data[i] = BLOCK_UNDEF;
1335
1336 for (i = 0; i < blocks; i++)
1337 d->revmap[i] = PAGE_UNDEF;
1338
1339 d->page_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1340 if (!d->page_buf)
1341 goto page_buf_fail;
1342
1343 d->oob_buf = kmalloc_array(2, mtd->oobavail, GFP_KERNEL);
1344 if (!d->oob_buf)
1345 goto oob_buf_fail;
1346
1347 mtdswap_scan_eblks(d);
1348
1349 return 0;
1350
1351 oob_buf_fail:
1352 kfree(d->page_buf);
1353 page_buf_fail:
1354 vfree(d->eb_data);
1355 eb_data_fail:
1356 vfree(d->revmap);
1357 revmap_fail:
1358 vfree(d->page_data);
1359 page_data_fail:
1360 printk(KERN_ERR "%s: init failed (%d)\n", MTDSWAP_PREFIX, ret);
1361 return ret;
1362 }
1363
1364 static void mtdswap_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
1365 {
1366 struct mtdswap_dev *d;
1367 struct mtd_blktrans_dev *mbd_dev;
1368 char *parts;
1369 char *this_opt;
1370 unsigned long part;
1371 unsigned int eblocks, eavailable, bad_blocks, spare_cnt;
1372 uint64_t swap_size, use_size, size_limit;
1373 int ret;
1374
1375 parts = &partitions[0];
1376 if (!*parts)
1377 return;
1378
1379 while ((this_opt = strsep(&parts, ",")) != NULL) {
1380 if (kstrtoul(this_opt, 0, &part) < 0)
1381 return;
1382
1383 if (mtd->index == part)
1384 break;
1385 }
1386
1387 if (mtd->index != part)
1388 return;
1389
1390 if (mtd->erasesize < PAGE_SIZE || mtd->erasesize % PAGE_SIZE) {
1391 printk(KERN_ERR "%s: Erase size %u not multiple of PAGE_SIZE "
1392 "%lu\n", MTDSWAP_PREFIX, mtd->erasesize, PAGE_SIZE);
1393 return;
1394 }
1395
1396 if (PAGE_SIZE % mtd->writesize || mtd->writesize > PAGE_SIZE) {
1397 printk(KERN_ERR "%s: PAGE_SIZE %lu not multiple of write size"
1398 " %u\n", MTDSWAP_PREFIX, PAGE_SIZE, mtd->writesize);
1399 return;
1400 }
1401
1402 if (!mtd->oobsize || mtd->oobavail < MTDSWAP_OOBSIZE) {
1403 printk(KERN_ERR "%s: Not enough free bytes in OOB, "
1404 "%d available, %zu needed.\n",
1405 MTDSWAP_PREFIX, mtd->oobavail, MTDSWAP_OOBSIZE);
1406 return;
1407 }
1408
1409 if (spare_eblocks > 100)
1410 spare_eblocks = 100;
1411
1412 use_size = mtd->size;
1413 size_limit = (uint64_t) BLOCK_MAX * PAGE_SIZE;
1414
1415 if (mtd->size > size_limit) {
1416 printk(KERN_WARNING "%s: Device too large. Limiting size to "
1417 "%llu bytes\n", MTDSWAP_PREFIX, size_limit);
1418 use_size = size_limit;
1419 }
1420
1421 eblocks = mtd_div_by_eb(use_size, mtd);
1422 use_size = (uint64_t)eblocks * mtd->erasesize;
1423 bad_blocks = mtdswap_badblocks(mtd, use_size);
1424 eavailable = eblocks - bad_blocks;
1425
1426 if (eavailable < MIN_ERASE_BLOCKS) {
1427 printk(KERN_ERR "%s: Not enough erase blocks. %u available, "
1428 "%d needed\n", MTDSWAP_PREFIX, eavailable,
1429 MIN_ERASE_BLOCKS);
1430 return;
1431 }
1432
1433 spare_cnt = div_u64((uint64_t)eavailable * spare_eblocks, 100);
1434
1435 if (spare_cnt < MIN_SPARE_EBLOCKS)
1436 spare_cnt = MIN_SPARE_EBLOCKS;
1437
1438 if (spare_cnt > eavailable - 1)
1439 spare_cnt = eavailable - 1;
1440
1441 swap_size = (uint64_t)(eavailable - spare_cnt) * mtd->erasesize +
1442 (header ? PAGE_SIZE : 0);
1443
1444 printk(KERN_INFO "%s: Enabling MTD swap on device %lu, size %llu KB, "
1445 "%u spare, %u bad blocks\n",
1446 MTDSWAP_PREFIX, part, swap_size / 1024, spare_cnt, bad_blocks);
1447
1448 d = kzalloc(sizeof(struct mtdswap_dev), GFP_KERNEL);
1449 if (!d)
1450 return;
1451
1452 mbd_dev = kzalloc(sizeof(struct mtd_blktrans_dev), GFP_KERNEL);
1453 if (!mbd_dev) {
1454 kfree(d);
1455 return;
1456 }
1457
1458 d->mbd_dev = mbd_dev;
1459 mbd_dev->priv = d;
1460
1461 mbd_dev->mtd = mtd;
1462 mbd_dev->devnum = mtd->index;
1463 mbd_dev->size = swap_size >> PAGE_SHIFT;
1464 mbd_dev->tr = tr;
1465
1466 if (!(mtd->flags & MTD_WRITEABLE))
1467 mbd_dev->readonly = 1;
1468
1469 if (mtdswap_init(d, eblocks, spare_cnt) < 0)
1470 goto init_failed;
1471
1472 if (add_mtd_blktrans_dev(mbd_dev) < 0)
1473 goto cleanup;
1474
1475 d->dev = disk_to_dev(mbd_dev->disk);
1476
1477 ret = mtdswap_add_debugfs(d);
1478 if (ret < 0)
1479 goto debugfs_failed;
1480
1481 return;
1482
1483 debugfs_failed:
1484 del_mtd_blktrans_dev(mbd_dev);
1485
1486 cleanup:
1487 mtdswap_cleanup(d);
1488
1489 init_failed:
1490 kfree(mbd_dev);
1491 kfree(d);
1492 }
1493
1494 static void mtdswap_remove_dev(struct mtd_blktrans_dev *dev)
1495 {
1496 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1497
1498 del_mtd_blktrans_dev(dev);
1499 mtdswap_cleanup(d);
1500 kfree(d);
1501 }
1502
1503 static struct mtd_blktrans_ops mtdswap_ops = {
1504 .name = "mtdswap",
1505 .major = 0,
1506 .part_bits = 0,
1507 .blksize = PAGE_SIZE,
1508 .flush = mtdswap_flush,
1509 .readsect = mtdswap_readsect,
1510 .writesect = mtdswap_writesect,
1511 .discard = mtdswap_discard,
1512 .background = mtdswap_background,
1513 .add_mtd = mtdswap_add_mtd,
1514 .remove_dev = mtdswap_remove_dev,
1515 .owner = THIS_MODULE,
1516 };
1517
1518 static int __init mtdswap_modinit(void)
1519 {
1520 return register_mtd_blktrans(&mtdswap_ops);
1521 }
1522
1523 static void __exit mtdswap_modexit(void)
1524 {
1525 deregister_mtd_blktrans(&mtdswap_ops);
1526 }
1527
1528 module_init(mtdswap_modinit);
1529 module_exit(mtdswap_modexit);
1530
1531
1532 MODULE_LICENSE("GPL");
1533 MODULE_AUTHOR("Jarkko Lavinen <jarkko.lavinen@nokia.com>");
1534 MODULE_DESCRIPTION("Block device access to an MTD suitable for using as "
1535 "swap space");
Linux with added FPC-III support