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Merge tag '6.10-rc6-smb3-server-fixes' of git://git.samba.org/ksmbd
[linux.git] / drivers / mtd / mtdswap.c
blob680366616da240039ecfb4cc59c83fcc4b1bf615
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Swap block device support for MTDs
4 * Turns an MTD device into a swap device with block wear leveling
5 *
6 * Copyright © 2007,2011 Nokia Corporation. All rights reserved.
7 *
8 * Authors: Jarkko Lavinen <jarkko.lavinen@nokia.com>
9 *
10 * Based on Richard Purdie's earlier implementation in 2007. Background
11 * support and lock-less operation written by Adrian Hunter.
12 */
13
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/mtd/mtd.h>
17 #include <linux/mtd/blktrans.h>
18 #include <linux/rbtree.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/vmalloc.h>
22 #include <linux/blkdev.h>
23 #include <linux/swap.h>
24 #include <linux/debugfs.h>
25 #include <linux/seq_file.h>
26 #include <linux/device.h>
27 #include <linux/math64.h>
28
29 #define MTDSWAP_PREFIX "mtdswap"
30
31 /*
32 * The number of free eraseblocks when GC should stop
33 */
34 #define CLEAN_BLOCK_THRESHOLD 20
35
36 /*
37 * Number of free eraseblocks below which GC can also collect low frag
38 * blocks.
39 */
40 #define LOW_FRAG_GC_THRESHOLD 5
41
42 /*
43 * Wear level cost amortization. We want to do wear leveling on the background
44 * without disturbing gc too much. This is made by defining max GC frequency.
45 * Frequency value 6 means 1/6 of the GC passes will pick an erase block based
46 * on the biggest wear difference rather than the biggest dirtiness.
47 *
48 * The lower freq2 should be chosen so that it makes sure the maximum erase
49 * difference will decrease even if a malicious application is deliberately
50 * trying to make erase differences large.
51 */
52 #define MAX_ERASE_DIFF 4000
53 #define COLLECT_NONDIRTY_BASE MAX_ERASE_DIFF
54 #define COLLECT_NONDIRTY_FREQ1 6
55 #define COLLECT_NONDIRTY_FREQ2 4
56
57 #define PAGE_UNDEF UINT_MAX
58 #define BLOCK_UNDEF UINT_MAX
59 #define BLOCK_ERROR (UINT_MAX - 1)
60 #define BLOCK_MAX (UINT_MAX - 2)
61
62 #define EBLOCK_BAD (1 << 0)
63 #define EBLOCK_NOMAGIC (1 << 1)
64 #define EBLOCK_BITFLIP (1 << 2)
65 #define EBLOCK_FAILED (1 << 3)
66 #define EBLOCK_READERR (1 << 4)
67 #define EBLOCK_IDX_SHIFT 5
68
69 struct swap_eb {
70 struct rb_node rb;
71 struct rb_root *root;
72
73 unsigned int flags;
74 unsigned int active_count;
75 unsigned int erase_count;
76 unsigned int pad; /* speeds up pointer decrement */
77 };
78
79 #define MTDSWAP_ECNT_MIN(rbroot) (rb_entry(rb_first(rbroot), struct swap_eb, \
80 rb)->erase_count)
81 #define MTDSWAP_ECNT_MAX(rbroot) (rb_entry(rb_last(rbroot), struct swap_eb, \
82 rb)->erase_count)
83
84 struct mtdswap_tree {
85 struct rb_root root;
86 unsigned int count;
87 };
88
89 enum {
90 MTDSWAP_CLEAN,
91 MTDSWAP_USED,
92 MTDSWAP_LOWFRAG,
93 MTDSWAP_HIFRAG,
94 MTDSWAP_DIRTY,
95 MTDSWAP_BITFLIP,
96 MTDSWAP_FAILING,
97 MTDSWAP_TREE_CNT,
98 };
99
100 struct mtdswap_dev {
101 struct mtd_blktrans_dev *mbd_dev;
102 struct mtd_info *mtd;
103 struct device *dev;
104
105 unsigned int *page_data;
106 unsigned int *revmap;
107
108 unsigned int eblks;
109 unsigned int spare_eblks;
110 unsigned int pages_per_eblk;
111 unsigned int max_erase_count;
112 struct swap_eb *eb_data;
113
114 struct mtdswap_tree trees[MTDSWAP_TREE_CNT];
115
116 unsigned long long sect_read_count;
117 unsigned long long sect_write_count;
118 unsigned long long mtd_write_count;
119 unsigned long long mtd_read_count;
120 unsigned long long discard_count;
121 unsigned long long discard_page_count;
122
123 unsigned int curr_write_pos;
124 struct swap_eb *curr_write;
125
126 char *page_buf;
127 char *oob_buf;
128 };
129
130 struct mtdswap_oobdata {
131 __le16 magic;
132 __le32 count;
133 } __packed;
134
135 #define MTDSWAP_MAGIC_CLEAN 0x2095
136 #define MTDSWAP_MAGIC_DIRTY (MTDSWAP_MAGIC_CLEAN + 1)
137 #define MTDSWAP_TYPE_CLEAN 0
138 #define MTDSWAP_TYPE_DIRTY 1
139 #define MTDSWAP_OOBSIZE sizeof(struct mtdswap_oobdata)
140
141 #define MTDSWAP_ERASE_RETRIES 3 /* Before marking erase block bad */
142 #define MTDSWAP_IO_RETRIES 3
143
144 enum {
145 MTDSWAP_SCANNED_CLEAN,
146 MTDSWAP_SCANNED_DIRTY,
147 MTDSWAP_SCANNED_BITFLIP,
148 MTDSWAP_SCANNED_BAD,
149 };
150
151 /*
152 * In the worst case mtdswap_writesect() has allocated the last clean
153 * page from the current block and is then pre-empted by the GC
154 * thread. The thread can consume a full erase block when moving a
155 * block.
156 */
157 #define MIN_SPARE_EBLOCKS 2
158 #define MIN_ERASE_BLOCKS (MIN_SPARE_EBLOCKS + 1)
159
160 #define TREE_ROOT(d, name) (&d->trees[MTDSWAP_ ## name].root)
161 #define TREE_EMPTY(d, name) (TREE_ROOT(d, name)->rb_node == NULL)
162 #define TREE_NONEMPTY(d, name) (!TREE_EMPTY(d, name))
163 #define TREE_COUNT(d, name) (d->trees[MTDSWAP_ ## name].count)
164
165 #define MTDSWAP_MBD_TO_MTDSWAP(dev) ((struct mtdswap_dev *)dev->priv)
166
167 static char partitions[128] = "";
168 module_param_string(partitions, partitions, sizeof(partitions), 0444);
169 MODULE_PARM_DESC(partitions, "MTD partition numbers to use as swap "
170 "partitions=\"1,3,5\"");
171
172 static unsigned int spare_eblocks = 10;
173 module_param(spare_eblocks, uint, 0444);
174 MODULE_PARM_DESC(spare_eblocks, "Percentage of spare erase blocks for "
175 "garbage collection (default 10%)");
176
177 static bool header; /* false */
178 module_param(header, bool, 0444);
179 MODULE_PARM_DESC(header,
180 "Include builtin swap header (default 0, without header)");
181
182 static int mtdswap_gc(struct mtdswap_dev *d, unsigned int background);
183
184 static loff_t mtdswap_eb_offset(struct mtdswap_dev *d, struct swap_eb *eb)
185 {
186 return (loff_t)(eb - d->eb_data) * d->mtd->erasesize;
187 }
188
189 static void mtdswap_eb_detach(struct mtdswap_dev *d, struct swap_eb *eb)
190 {
191 unsigned int oldidx;
192 struct mtdswap_tree *tp;
193
194 if (eb->root) {
195 tp = container_of(eb->root, struct mtdswap_tree, root);
196 oldidx = tp - &d->trees[0];
197
198 d->trees[oldidx].count--;
199 rb_erase(&eb->rb, eb->root);
200 }
201 }
202
203 static void __mtdswap_rb_add(struct rb_root *root, struct swap_eb *eb)
204 {
205 struct rb_node **p, *parent = NULL;
206 struct swap_eb *cur;
207
208 p = &root->rb_node;
209 while (*p) {
210 parent = *p;
211 cur = rb_entry(parent, struct swap_eb, rb);
212 if (eb->erase_count > cur->erase_count)
213 p = &(*p)->rb_right;
214 else
215 p = &(*p)->rb_left;
216 }
217
218 rb_link_node(&eb->rb, parent, p);
219 rb_insert_color(&eb->rb, root);
220 }
221
222 static void mtdswap_rb_add(struct mtdswap_dev *d, struct swap_eb *eb, int idx)
223 {
224 struct rb_root *root;
225
226 if (eb->root == &d->trees[idx].root)
227 return;
228
229 mtdswap_eb_detach(d, eb);
230 root = &d->trees[idx].root;
231 __mtdswap_rb_add(root, eb);
232 eb->root = root;
233 d->trees[idx].count++;
234 }
235
236 static struct rb_node *mtdswap_rb_index(struct rb_root *root, unsigned int idx)
237 {
238 struct rb_node *p;
239 unsigned int i;
240
241 p = rb_first(root);
242 i = 0;
243 while (i < idx && p) {
244 p = rb_next(p);
245 i++;
246 }
247
248 return p;
249 }
250
251 static int mtdswap_handle_badblock(struct mtdswap_dev *d, struct swap_eb *eb)
252 {
253 int ret;
254 loff_t offset;
255
256 d->spare_eblks--;
257 eb->flags |= EBLOCK_BAD;
258 mtdswap_eb_detach(d, eb);
259 eb->root = NULL;
260
261 /* badblocks not supported */
262 if (!mtd_can_have_bb(d->mtd))
263 return 1;
264
265 offset = mtdswap_eb_offset(d, eb);
266 dev_warn(d->dev, "Marking bad block at %08llx\n", offset);
267 ret = mtd_block_markbad(d->mtd, offset);
268
269 if (ret) {
270 dev_warn(d->dev, "Mark block bad failed for block at %08llx "
271 "error %d\n", offset, ret);
272 return ret;
273 }
274
275 return 1;
276
277 }
278
279 static int mtdswap_handle_write_error(struct mtdswap_dev *d, struct swap_eb *eb)
280 {
281 unsigned int marked = eb->flags & EBLOCK_FAILED;
282 struct swap_eb *curr_write = d->curr_write;
283
284 eb->flags |= EBLOCK_FAILED;
285 if (curr_write == eb) {
286 d->curr_write = NULL;
287
288 if (!marked && d->curr_write_pos != 0) {
289 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
290 return 0;
291 }
292 }
293
294 return mtdswap_handle_badblock(d, eb);
295 }
296
297 static int mtdswap_read_oob(struct mtdswap_dev *d, loff_t from,
298 struct mtd_oob_ops *ops)
299 {
300 int ret = mtd_read_oob(d->mtd, from, ops);
301
302 if (mtd_is_bitflip(ret))
303 return ret;
304
305 if (ret) {
306 dev_warn(d->dev, "Read OOB failed %d for block at %08llx\n",
307 ret, from);
308 return ret;
309 }
310
311 if (ops->oobretlen < ops->ooblen) {
312 dev_warn(d->dev, "Read OOB return short read (%zd bytes not "
313 "%zd) for block at %08llx\n",
314 ops->oobretlen, ops->ooblen, from);
315 return -EIO;
316 }
317
318 return 0;
319 }
320
321 static int mtdswap_read_markers(struct mtdswap_dev *d, struct swap_eb *eb)
322 {
323 struct mtdswap_oobdata *data, *data2;
324 int ret;
325 loff_t offset;
326 struct mtd_oob_ops ops = { };
327
328 offset = mtdswap_eb_offset(d, eb);
329
330 /* Check first if the block is bad. */
331 if (mtd_can_have_bb(d->mtd) && mtd_block_isbad(d->mtd, offset))
332 return MTDSWAP_SCANNED_BAD;
333
334 ops.ooblen = 2 * d->mtd->oobavail;
335 ops.oobbuf = d->oob_buf;
336 ops.ooboffs = 0;
337 ops.datbuf = NULL;
338 ops.mode = MTD_OPS_AUTO_OOB;
339
340 ret = mtdswap_read_oob(d, offset, &ops);
341
342 if (ret && !mtd_is_bitflip(ret))
343 return ret;
344
345 data = (struct mtdswap_oobdata *)d->oob_buf;
346 data2 = (struct mtdswap_oobdata *)
347 (d->oob_buf + d->mtd->oobavail);
348
349 if (le16_to_cpu(data->magic) == MTDSWAP_MAGIC_CLEAN) {
350 eb->erase_count = le32_to_cpu(data->count);
351 if (mtd_is_bitflip(ret))
352 ret = MTDSWAP_SCANNED_BITFLIP;
353 else {
354 if (le16_to_cpu(data2->magic) == MTDSWAP_MAGIC_DIRTY)
355 ret = MTDSWAP_SCANNED_DIRTY;
356 else
357 ret = MTDSWAP_SCANNED_CLEAN;
358 }
359 } else {
360 eb->flags |= EBLOCK_NOMAGIC;
361 ret = MTDSWAP_SCANNED_DIRTY;
362 }
363
364 return ret;
365 }
366
367 static int mtdswap_write_marker(struct mtdswap_dev *d, struct swap_eb *eb,
368 u16 marker)
369 {
370 struct mtdswap_oobdata n;
371 int ret;
372 loff_t offset;
373 struct mtd_oob_ops ops = { };
374
375 ops.ooboffs = 0;
376 ops.oobbuf = (uint8_t *)&n;
377 ops.mode = MTD_OPS_AUTO_OOB;
378 ops.datbuf = NULL;
379
380 if (marker == MTDSWAP_TYPE_CLEAN) {
381 n.magic = cpu_to_le16(MTDSWAP_MAGIC_CLEAN);
382 n.count = cpu_to_le32(eb->erase_count);
383 ops.ooblen = MTDSWAP_OOBSIZE;
384 offset = mtdswap_eb_offset(d, eb);
385 } else {
386 n.magic = cpu_to_le16(MTDSWAP_MAGIC_DIRTY);
387 ops.ooblen = sizeof(n.magic);
388 offset = mtdswap_eb_offset(d, eb) + d->mtd->writesize;
389 }
390
391 ret = mtd_write_oob(d->mtd, offset, &ops);
392
393 if (ret) {
394 dev_warn(d->dev, "Write OOB failed for block at %08llx "
395 "error %d\n", offset, ret);
396 if (ret == -EIO || mtd_is_eccerr(ret))
397 mtdswap_handle_write_error(d, eb);
398 return ret;
399 }
400
401 if (ops.oobretlen != ops.ooblen) {
402 dev_warn(d->dev, "Short OOB write for block at %08llx: "
403 "%zd not %zd\n",
404 offset, ops.oobretlen, ops.ooblen);
405 return ret;
406 }
407
408 return 0;
409 }
410
411 /*
412 * Are there any erase blocks without MAGIC_CLEAN header, presumably
413 * because power was cut off after erase but before header write? We
414 * need to guestimate the erase count.
415 */
416 static void mtdswap_check_counts(struct mtdswap_dev *d)
417 {
418 struct rb_root hist_root = RB_ROOT;
419 struct rb_node *medrb;
420 struct swap_eb *eb;
421 unsigned int i, cnt, median;
422
423 cnt = 0;
424 for (i = 0; i < d->eblks; i++) {
425 eb = d->eb_data + i;
426
427 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_BAD | EBLOCK_READERR))
428 continue;
429
430 __mtdswap_rb_add(&hist_root, eb);
431 cnt++;
432 }
433
434 if (cnt == 0)
435 return;
436
437 medrb = mtdswap_rb_index(&hist_root, cnt / 2);
438 median = rb_entry(medrb, struct swap_eb, rb)->erase_count;
439
440 d->max_erase_count = MTDSWAP_ECNT_MAX(&hist_root);
441
442 for (i = 0; i < d->eblks; i++) {
443 eb = d->eb_data + i;
444
445 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_READERR))
446 eb->erase_count = median;
447
448 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_BAD | EBLOCK_READERR))
449 continue;
450
451 rb_erase(&eb->rb, &hist_root);
452 }
453 }
454
455 static void mtdswap_scan_eblks(struct mtdswap_dev *d)
456 {
457 int status;
458 unsigned int i, idx;
459 struct swap_eb *eb;
460
461 for (i = 0; i < d->eblks; i++) {
462 eb = d->eb_data + i;
463
464 status = mtdswap_read_markers(d, eb);
465 if (status < 0)
466 eb->flags |= EBLOCK_READERR;
467 else if (status == MTDSWAP_SCANNED_BAD) {
468 eb->flags |= EBLOCK_BAD;
469 continue;
470 }
471
472 switch (status) {
473 case MTDSWAP_SCANNED_CLEAN:
474 idx = MTDSWAP_CLEAN;
475 break;
476 case MTDSWAP_SCANNED_DIRTY:
477 case MTDSWAP_SCANNED_BITFLIP:
478 idx = MTDSWAP_DIRTY;
479 break;
480 default:
481 idx = MTDSWAP_FAILING;
482 }
483
484 eb->flags |= (idx << EBLOCK_IDX_SHIFT);
485 }
486
487 mtdswap_check_counts(d);
488
489 for (i = 0; i < d->eblks; i++) {
490 eb = d->eb_data + i;
491
492 if (eb->flags & EBLOCK_BAD)
493 continue;
494
495 idx = eb->flags >> EBLOCK_IDX_SHIFT;
496 mtdswap_rb_add(d, eb, idx);
497 }
498 }
499
500 /*
501 * Place eblk into a tree corresponding to its number of active blocks
502 * it contains.
503 */
504 static void mtdswap_store_eb(struct mtdswap_dev *d, struct swap_eb *eb)
505 {
506 unsigned int weight = eb->active_count;
507 unsigned int maxweight = d->pages_per_eblk;
508
509 if (eb == d->curr_write)
510 return;
511
512 if (eb->flags & EBLOCK_BITFLIP)
513 mtdswap_rb_add(d, eb, MTDSWAP_BITFLIP);
514 else if (eb->flags & (EBLOCK_READERR | EBLOCK_FAILED))
515 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
516 if (weight == maxweight)
517 mtdswap_rb_add(d, eb, MTDSWAP_USED);
518 else if (weight == 0)
519 mtdswap_rb_add(d, eb, MTDSWAP_DIRTY);
520 else if (weight > (maxweight/2))
521 mtdswap_rb_add(d, eb, MTDSWAP_LOWFRAG);
522 else
523 mtdswap_rb_add(d, eb, MTDSWAP_HIFRAG);
524 }
525
526 static int mtdswap_erase_block(struct mtdswap_dev *d, struct swap_eb *eb)
527 {
528 struct mtd_info *mtd = d->mtd;
529 struct erase_info erase;
530 unsigned int retries = 0;
531 int ret;
532
533 eb->erase_count++;
534 if (eb->erase_count > d->max_erase_count)
535 d->max_erase_count = eb->erase_count;
536
537 retry:
538 memset(&erase, 0, sizeof(struct erase_info));
539 erase.addr = mtdswap_eb_offset(d, eb);
540 erase.len = mtd->erasesize;
541
542 ret = mtd_erase(mtd, &erase);
543 if (ret) {
544 if (retries++ < MTDSWAP_ERASE_RETRIES) {
545 dev_warn(d->dev,
546 "erase of erase block %#llx on %s failed",
547 erase.addr, mtd->name);
548 yield();
549 goto retry;
550 }
551
552 dev_err(d->dev, "Cannot erase erase block %#llx on %s\n",
553 erase.addr, mtd->name);
554
555 mtdswap_handle_badblock(d, eb);
556 return -EIO;
557 }
558
559 return 0;
560 }
561
562 static int mtdswap_map_free_block(struct mtdswap_dev *d, unsigned int page,
563 unsigned int *block)
564 {
565 int ret;
566 struct swap_eb *old_eb = d->curr_write;
567 struct rb_root *clean_root;
568 struct swap_eb *eb;
569
570 if (old_eb == NULL || d->curr_write_pos >= d->pages_per_eblk) {
571 do {
572 if (TREE_EMPTY(d, CLEAN))
573 return -ENOSPC;
574
575 clean_root = TREE_ROOT(d, CLEAN);
576 eb = rb_entry(rb_first(clean_root), struct swap_eb, rb);
577 rb_erase(&eb->rb, clean_root);
578 eb->root = NULL;
579 TREE_COUNT(d, CLEAN)--;
580
581 ret = mtdswap_write_marker(d, eb, MTDSWAP_TYPE_DIRTY);
582 } while (ret == -EIO || mtd_is_eccerr(ret));
583
584 if (ret)
585 return ret;
586
587 d->curr_write_pos = 0;
588 d->curr_write = eb;
589 if (old_eb)
590 mtdswap_store_eb(d, old_eb);
591 }
592
593 *block = (d->curr_write - d->eb_data) * d->pages_per_eblk +
594 d->curr_write_pos;
595
596 d->curr_write->active_count++;
597 d->revmap[*block] = page;
598 d->curr_write_pos++;
599
600 return 0;
601 }
602
603 static unsigned int mtdswap_free_page_cnt(struct mtdswap_dev *d)
604 {
605 return TREE_COUNT(d, CLEAN) * d->pages_per_eblk +
606 d->pages_per_eblk - d->curr_write_pos;
607 }
608
609 static unsigned int mtdswap_enough_free_pages(struct mtdswap_dev *d)
610 {
611 return mtdswap_free_page_cnt(d) > d->pages_per_eblk;
612 }
613
614 static int mtdswap_write_block(struct mtdswap_dev *d, char *buf,
615 unsigned int page, unsigned int *bp, int gc_context)
616 {
617 struct mtd_info *mtd = d->mtd;
618 struct swap_eb *eb;
619 size_t retlen;
620 loff_t writepos;
621 int ret;
622
623 retry:
624 if (!gc_context)
625 while (!mtdswap_enough_free_pages(d))
626 if (mtdswap_gc(d, 0) > 0)
627 return -ENOSPC;
628
629 ret = mtdswap_map_free_block(d, page, bp);
630 eb = d->eb_data + (*bp / d->pages_per_eblk);
631
632 if (ret == -EIO || mtd_is_eccerr(ret)) {
633 d->curr_write = NULL;
634 eb->active_count--;
635 d->revmap[*bp] = PAGE_UNDEF;
636 goto retry;
637 }
638
639 if (ret < 0)
640 return ret;
641
642 writepos = (loff_t)*bp << PAGE_SHIFT;
643 ret = mtd_write(mtd, writepos, PAGE_SIZE, &retlen, buf);
644 if (ret == -EIO || mtd_is_eccerr(ret)) {
645 d->curr_write_pos--;
646 eb->active_count--;
647 d->revmap[*bp] = PAGE_UNDEF;
648 mtdswap_handle_write_error(d, eb);
649 goto retry;
650 }
651
652 if (ret < 0) {
653 dev_err(d->dev, "Write to MTD device failed: %d (%zd written)",
654 ret, retlen);
655 goto err;
656 }
657
658 if (retlen != PAGE_SIZE) {
659 dev_err(d->dev, "Short write to MTD device: %zd written",
660 retlen);
661 ret = -EIO;
662 goto err;
663 }
664
665 return ret;
666
667 err:
668 d->curr_write_pos--;
669 eb->active_count--;
670 d->revmap[*bp] = PAGE_UNDEF;
671
672 return ret;
673 }
674
675 static int mtdswap_move_block(struct mtdswap_dev *d, unsigned int oldblock,
676 unsigned int *newblock)
677 {
678 struct mtd_info *mtd = d->mtd;
679 struct swap_eb *eb, *oldeb;
680 int ret;
681 size_t retlen;
682 unsigned int page, retries;
683 loff_t readpos;
684
685 page = d->revmap[oldblock];
686 readpos = (loff_t) oldblock << PAGE_SHIFT;
687 retries = 0;
688
689 retry:
690 ret = mtd_read(mtd, readpos, PAGE_SIZE, &retlen, d->page_buf);
691
692 if (ret < 0 && !mtd_is_bitflip(ret)) {
693 oldeb = d->eb_data + oldblock / d->pages_per_eblk;
694 oldeb->flags |= EBLOCK_READERR;
695
696 dev_err(d->dev, "Read Error: %d (block %u)\n", ret,
697 oldblock);
698 retries++;
699 if (retries < MTDSWAP_IO_RETRIES)
700 goto retry;
701
702 goto read_error;
703 }
704
705 if (retlen != PAGE_SIZE) {
706 dev_err(d->dev, "Short read: %zd (block %u)\n", retlen,
707 oldblock);
708 ret = -EIO;
709 goto read_error;
710 }
711
712 ret = mtdswap_write_block(d, d->page_buf, page, newblock, 1);
713 if (ret < 0) {
714 d->page_data[page] = BLOCK_ERROR;
715 dev_err(d->dev, "Write error: %d\n", ret);
716 return ret;
717 }
718
719 d->page_data[page] = *newblock;
720 d->revmap[oldblock] = PAGE_UNDEF;
721 eb = d->eb_data + oldblock / d->pages_per_eblk;
722 eb->active_count--;
723
724 return 0;
725
726 read_error:
727 d->page_data[page] = BLOCK_ERROR;
728 d->revmap[oldblock] = PAGE_UNDEF;
729 return ret;
730 }
731
732 static int mtdswap_gc_eblock(struct mtdswap_dev *d, struct swap_eb *eb)
733 {
734 unsigned int i, block, eblk_base, newblock;
735 int ret, errcode;
736
737 errcode = 0;
738 eblk_base = (eb - d->eb_data) * d->pages_per_eblk;
739
740 for (i = 0; i < d->pages_per_eblk; i++) {
741 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
742 return -ENOSPC;
743
744 block = eblk_base + i;
745 if (d->revmap[block] == PAGE_UNDEF)
746 continue;
747
748 ret = mtdswap_move_block(d, block, &newblock);
749 if (ret < 0 && !errcode)
750 errcode = ret;
751 }
752
753 return errcode;
754 }
755
756 static int __mtdswap_choose_gc_tree(struct mtdswap_dev *d)
757 {
758 int idx, stopat;
759
760 if (TREE_COUNT(d, CLEAN) < LOW_FRAG_GC_THRESHOLD)
761 stopat = MTDSWAP_LOWFRAG;
762 else
763 stopat = MTDSWAP_HIFRAG;
764
765 for (idx = MTDSWAP_BITFLIP; idx >= stopat; idx--)
766 if (d->trees[idx].root.rb_node != NULL)
767 return idx;
768
769 return -1;
770 }
771
772 static int mtdswap_wlfreq(unsigned int maxdiff)
773 {
774 unsigned int h, x, y, dist, base;
775
776 /*
777 * Calculate linear ramp down from f1 to f2 when maxdiff goes from
778 * MAX_ERASE_DIFF to MAX_ERASE_DIFF + COLLECT_NONDIRTY_BASE. Similar
779 * to triangle with height f1 - f1 and width COLLECT_NONDIRTY_BASE.
780 */
781
782 dist = maxdiff - MAX_ERASE_DIFF;
783 if (dist > COLLECT_NONDIRTY_BASE)
784 dist = COLLECT_NONDIRTY_BASE;
785
786 /*
787 * Modelling the slop as right angular triangle with base
788 * COLLECT_NONDIRTY_BASE and height freq1 - freq2. The ratio y/x is
789 * equal to the ratio h/base.
790 */
791 h = COLLECT_NONDIRTY_FREQ1 - COLLECT_NONDIRTY_FREQ2;
792 base = COLLECT_NONDIRTY_BASE;
793
794 x = dist - base;
795 y = (x * h + base / 2) / base;
796
797 return COLLECT_NONDIRTY_FREQ2 + y;
798 }
799
800 static int mtdswap_choose_wl_tree(struct mtdswap_dev *d)
801 {
802 static unsigned int pick_cnt;
803 unsigned int i, idx = -1, wear, max;
804 struct rb_root *root;
805
806 max = 0;
807 for (i = 0; i <= MTDSWAP_DIRTY; i++) {
808 root = &d->trees[i].root;
809 if (root->rb_node == NULL)
810 continue;
811
812 wear = d->max_erase_count - MTDSWAP_ECNT_MIN(root);
813 if (wear > max) {
814 max = wear;
815 idx = i;
816 }
817 }
818
819 if (max > MAX_ERASE_DIFF && pick_cnt >= mtdswap_wlfreq(max) - 1) {
820 pick_cnt = 0;
821 return idx;
822 }
823
824 pick_cnt++;
825 return -1;
826 }
827
828 static int mtdswap_choose_gc_tree(struct mtdswap_dev *d,
829 unsigned int background)
830 {
831 int idx;
832
833 if (TREE_NONEMPTY(d, FAILING) &&
834 (background || (TREE_EMPTY(d, CLEAN) && TREE_EMPTY(d, DIRTY))))
835 return MTDSWAP_FAILING;
836
837 idx = mtdswap_choose_wl_tree(d);
838 if (idx >= MTDSWAP_CLEAN)
839 return idx;
840
841 return __mtdswap_choose_gc_tree(d);
842 }
843
844 static struct swap_eb *mtdswap_pick_gc_eblk(struct mtdswap_dev *d,
845 unsigned int background)
846 {
847 struct rb_root *rp = NULL;
848 struct swap_eb *eb = NULL;
849 int idx;
850
851 if (background && TREE_COUNT(d, CLEAN) > CLEAN_BLOCK_THRESHOLD &&
852 TREE_EMPTY(d, DIRTY) && TREE_EMPTY(d, FAILING))
853 return NULL;
854
855 idx = mtdswap_choose_gc_tree(d, background);
856 if (idx < 0)
857 return NULL;
858
859 rp = &d->trees[idx].root;
860 eb = rb_entry(rb_first(rp), struct swap_eb, rb);
861
862 rb_erase(&eb->rb, rp);
863 eb->root = NULL;
864 d->trees[idx].count--;
865 return eb;
866 }
867
868 static unsigned int mtdswap_test_patt(unsigned int i)
869 {
870 return i % 2 ? 0x55555555 : 0xAAAAAAAA;
871 }
872
873 static unsigned int mtdswap_eblk_passes(struct mtdswap_dev *d,
874 struct swap_eb *eb)
875 {
876 struct mtd_info *mtd = d->mtd;
877 unsigned int test, i, j, patt, mtd_pages;
878 loff_t base, pos;
879 unsigned int *p1 = (unsigned int *)d->page_buf;
880 unsigned char *p2 = (unsigned char *)d->oob_buf;
881 struct mtd_oob_ops ops = { };
882 int ret;
883
884 ops.mode = MTD_OPS_AUTO_OOB;
885 ops.len = mtd->writesize;
886 ops.ooblen = mtd->oobavail;
887 ops.ooboffs = 0;
888 ops.datbuf = d->page_buf;
889 ops.oobbuf = d->oob_buf;
890 base = mtdswap_eb_offset(d, eb);
891 mtd_pages = d->pages_per_eblk * PAGE_SIZE / mtd->writesize;
892
893 for (test = 0; test < 2; test++) {
894 pos = base;
895 for (i = 0; i < mtd_pages; i++) {
896 patt = mtdswap_test_patt(test + i);
897 memset(d->page_buf, patt, mtd->writesize);
898 memset(d->oob_buf, patt, mtd->oobavail);
899 ret = mtd_write_oob(mtd, pos, &ops);
900 if (ret)
901 goto error;
902
903 pos += mtd->writesize;
904 }
905
906 pos = base;
907 for (i = 0; i < mtd_pages; i++) {
908 ret = mtd_read_oob(mtd, pos, &ops);
909 if (ret)
910 goto error;
911
912 patt = mtdswap_test_patt(test + i);
913 for (j = 0; j < mtd->writesize/sizeof(int); j++)
914 if (p1[j] != patt)
915 goto error;
916
917 for (j = 0; j < mtd->oobavail; j++)
918 if (p2[j] != (unsigned char)patt)
919 goto error;
920
921 pos += mtd->writesize;
922 }
923
924 ret = mtdswap_erase_block(d, eb);
925 if (ret)
926 goto error;
927 }
928
929 eb->flags &= ~EBLOCK_READERR;
930 return 1;
931
932 error:
933 mtdswap_handle_badblock(d, eb);
934 return 0;
935 }
936
937 static int mtdswap_gc(struct mtdswap_dev *d, unsigned int background)
938 {
939 struct swap_eb *eb;
940 int ret;
941
942 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
943 return 1;
944
945 eb = mtdswap_pick_gc_eblk(d, background);
946 if (!eb)
947 return 1;
948
949 ret = mtdswap_gc_eblock(d, eb);
950 if (ret == -ENOSPC)
951 return 1;
952
953 if (eb->flags & EBLOCK_FAILED) {
954 mtdswap_handle_badblock(d, eb);
955 return 0;
956 }
957
958 eb->flags &= ~EBLOCK_BITFLIP;
959 ret = mtdswap_erase_block(d, eb);
960 if ((eb->flags & EBLOCK_READERR) &&
961 (ret || !mtdswap_eblk_passes(d, eb)))
962 return 0;
963
964 if (ret == 0)
965 ret = mtdswap_write_marker(d, eb, MTDSWAP_TYPE_CLEAN);
966
967 if (ret == 0)
968 mtdswap_rb_add(d, eb, MTDSWAP_CLEAN);
969 else if (ret != -EIO && !mtd_is_eccerr(ret))
970 mtdswap_rb_add(d, eb, MTDSWAP_DIRTY);
971
972 return 0;
973 }
974
975 static void mtdswap_background(struct mtd_blktrans_dev *dev)
976 {
977 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
978 int ret;
979
980 while (1) {
981 ret = mtdswap_gc(d, 1);
982 if (ret || mtd_blktrans_cease_background(dev))
983 return;
984 }
985 }
986
987 static void mtdswap_cleanup(struct mtdswap_dev *d)
988 {
989 vfree(d->eb_data);
990 vfree(d->revmap);
991 vfree(d->page_data);
992 kfree(d->oob_buf);
993 kfree(d->page_buf);
994 }
995
996 static int mtdswap_flush(struct mtd_blktrans_dev *dev)
997 {
998 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
999
1000 mtd_sync(d->mtd);
1001 return 0;
1002 }
1003
1004 static unsigned int mtdswap_badblocks(struct mtd_info *mtd, uint64_t size)
1005 {
1006 loff_t offset;
1007 unsigned int badcnt;
1008
1009 badcnt = 0;
1010
1011 if (mtd_can_have_bb(mtd))
1012 for (offset = 0; offset < size; offset += mtd->erasesize)
1013 if (mtd_block_isbad(mtd, offset))
1014 badcnt++;
1015
1016 return badcnt;
1017 }
1018
1019 static int mtdswap_writesect(struct mtd_blktrans_dev *dev,
1020 unsigned long page, char *buf)
1021 {
1022 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1023 unsigned int newblock, mapped;
1024 struct swap_eb *eb;
1025 int ret;
1026
1027 d->sect_write_count++;
1028
1029 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
1030 return -ENOSPC;
1031
1032 if (header) {
1033 /* Ignore writes to the header page */
1034 if (unlikely(page == 0))
1035 return 0;
1036
1037 page--;
1038 }
1039
1040 mapped = d->page_data[page];
1041 if (mapped <= BLOCK_MAX) {
1042 eb = d->eb_data + (mapped / d->pages_per_eblk);
1043 eb->active_count--;
1044 mtdswap_store_eb(d, eb);
1045 d->page_data[page] = BLOCK_UNDEF;
1046 d->revmap[mapped] = PAGE_UNDEF;
1047 }
1048
1049 ret = mtdswap_write_block(d, buf, page, &newblock, 0);
1050 d->mtd_write_count++;
1051
1052 if (ret < 0)
1053 return ret;
1054
1055 d->page_data[page] = newblock;
1056
1057 return 0;
1058 }
1059
1060 /* Provide a dummy swap header for the kernel */
1061 static int mtdswap_auto_header(struct mtdswap_dev *d, char *buf)
1062 {
1063 union swap_header *hd = (union swap_header *)(buf);
1064
1065 memset(buf, 0, PAGE_SIZE - 10);
1066
1067 hd->info.version = 1;
1068 hd->info.last_page = d->mbd_dev->size - 1;
1069 hd->info.nr_badpages = 0;
1070
1071 memcpy(buf + PAGE_SIZE - 10, "SWAPSPACE2", 10);
1072
1073 return 0;
1074 }
1075
1076 static int mtdswap_readsect(struct mtd_blktrans_dev *dev,
1077 unsigned long page, char *buf)
1078 {
1079 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1080 struct mtd_info *mtd = d->mtd;
1081 unsigned int realblock, retries;
1082 loff_t readpos;
1083 struct swap_eb *eb;
1084 size_t retlen;
1085 int ret;
1086
1087 d->sect_read_count++;
1088
1089 if (header) {
1090 if (unlikely(page == 0))
1091 return mtdswap_auto_header(d, buf);
1092
1093 page--;
1094 }
1095
1096 realblock = d->page_data[page];
1097 if (realblock > BLOCK_MAX) {
1098 memset(buf, 0x0, PAGE_SIZE);
1099 if (realblock == BLOCK_UNDEF)
1100 return 0;
1101 else
1102 return -EIO;
1103 }
1104
1105 eb = d->eb_data + (realblock / d->pages_per_eblk);
1106 BUG_ON(d->revmap[realblock] == PAGE_UNDEF);
1107
1108 readpos = (loff_t)realblock << PAGE_SHIFT;
1109 retries = 0;
1110
1111 retry:
1112 ret = mtd_read(mtd, readpos, PAGE_SIZE, &retlen, buf);
1113
1114 d->mtd_read_count++;
1115 if (mtd_is_bitflip(ret)) {
1116 eb->flags |= EBLOCK_BITFLIP;
1117 mtdswap_rb_add(d, eb, MTDSWAP_BITFLIP);
1118 ret = 0;
1119 }
1120
1121 if (ret < 0) {
1122 dev_err(d->dev, "Read error %d\n", ret);
1123 eb->flags |= EBLOCK_READERR;
1124 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
1125 retries++;
1126 if (retries < MTDSWAP_IO_RETRIES)
1127 goto retry;
1128
1129 return ret;
1130 }
1131
1132 if (retlen != PAGE_SIZE) {
1133 dev_err(d->dev, "Short read %zd\n", retlen);
1134 return -EIO;
1135 }
1136
1137 return 0;
1138 }
1139
1140 static int mtdswap_discard(struct mtd_blktrans_dev *dev, unsigned long first,
1141 unsigned nr_pages)
1142 {
1143 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1144 unsigned long page;
1145 struct swap_eb *eb;
1146 unsigned int mapped;
1147
1148 d->discard_count++;
1149
1150 for (page = first; page < first + nr_pages; page++) {
1151 mapped = d->page_data[page];
1152 if (mapped <= BLOCK_MAX) {
1153 eb = d->eb_data + (mapped / d->pages_per_eblk);
1154 eb->active_count--;
1155 mtdswap_store_eb(d, eb);
1156 d->page_data[page] = BLOCK_UNDEF;
1157 d->revmap[mapped] = PAGE_UNDEF;
1158 d->discard_page_count++;
1159 } else if (mapped == BLOCK_ERROR) {
1160 d->page_data[page] = BLOCK_UNDEF;
1161 d->discard_page_count++;
1162 }
1163 }
1164
1165 return 0;
1166 }
1167
1168 static int mtdswap_show(struct seq_file *s, void *data)
1169 {
1170 struct mtdswap_dev *d = (struct mtdswap_dev *) s->private;
1171 unsigned long sum;
1172 unsigned int count[MTDSWAP_TREE_CNT];
1173 unsigned int min[MTDSWAP_TREE_CNT];
1174 unsigned int max[MTDSWAP_TREE_CNT];
1175 unsigned int i, cw = 0, cwp = 0, cwecount = 0, bb_cnt, mapped, pages;
1176 uint64_t use_size;
1177 static const char * const name[] = {
1178 "clean", "used", "low", "high", "dirty", "bitflip", "failing"
1179 };
1180
1181 mutex_lock(&d->mbd_dev->lock);
1182
1183 for (i = 0; i < MTDSWAP_TREE_CNT; i++) {
1184 struct rb_root *root = &d->trees[i].root;
1185
1186 if (root->rb_node) {
1187 count[i] = d->trees[i].count;
1188 min[i] = MTDSWAP_ECNT_MIN(root);
1189 max[i] = MTDSWAP_ECNT_MAX(root);
1190 } else
1191 count[i] = 0;
1192 }
1193
1194 if (d->curr_write) {
1195 cw = 1;
1196 cwp = d->curr_write_pos;
1197 cwecount = d->curr_write->erase_count;
1198 }
1199
1200 sum = 0;
1201 for (i = 0; i < d->eblks; i++)
1202 sum += d->eb_data[i].erase_count;
1203
1204 use_size = (uint64_t)d->eblks * d->mtd->erasesize;
1205 bb_cnt = mtdswap_badblocks(d->mtd, use_size);
1206
1207 mapped = 0;
1208 pages = d->mbd_dev->size;
1209 for (i = 0; i < pages; i++)
1210 if (d->page_data[i] != BLOCK_UNDEF)
1211 mapped++;
1212
1213 mutex_unlock(&d->mbd_dev->lock);
1214
1215 for (i = 0; i < MTDSWAP_TREE_CNT; i++) {
1216 if (!count[i])
1217 continue;
1218
1219 if (min[i] != max[i])
1220 seq_printf(s, "%s:\t%5d erase blocks, erased min %d, "
1221 "max %d times\n",
1222 name[i], count[i], min[i], max[i]);
1223 else
1224 seq_printf(s, "%s:\t%5d erase blocks, all erased %d "
1225 "times\n", name[i], count[i], min[i]);
1226 }
1227
1228 if (bb_cnt)
1229 seq_printf(s, "bad:\t%5u erase blocks\n", bb_cnt);
1230
1231 if (cw)
1232 seq_printf(s, "current erase block: %u pages used, %u free, "
1233 "erased %u times\n",
1234 cwp, d->pages_per_eblk - cwp, cwecount);
1235
1236 seq_printf(s, "total erasures: %lu\n", sum);
1237
1238 seq_puts(s, "\n");
1239
1240 seq_printf(s, "mtdswap_readsect count: %llu\n", d->sect_read_count);
1241 seq_printf(s, "mtdswap_writesect count: %llu\n", d->sect_write_count);
1242 seq_printf(s, "mtdswap_discard count: %llu\n", d->discard_count);
1243 seq_printf(s, "mtd read count: %llu\n", d->mtd_read_count);
1244 seq_printf(s, "mtd write count: %llu\n", d->mtd_write_count);
1245 seq_printf(s, "discarded pages count: %llu\n", d->discard_page_count);
1246
1247 seq_puts(s, "\n");
1248 seq_printf(s, "total pages: %u\n", pages);
1249 seq_printf(s, "pages mapped: %u\n", mapped);
1250
1251 return 0;
1252 }
1253 DEFINE_SHOW_ATTRIBUTE(mtdswap);
1254
1255 static int mtdswap_add_debugfs(struct mtdswap_dev *d)
1256 {
1257 struct dentry *root = d->mtd->dbg.dfs_dir;
1258
1259 if (!IS_ENABLED(CONFIG_DEBUG_FS))
1260 return 0;
1261
1262 if (IS_ERR_OR_NULL(root))
1263 return -1;
1264
1265 debugfs_create_file("mtdswap_stats", S_IRUSR, root, d, &mtdswap_fops);
1266
1267 return 0;
1268 }
1269
1270 static int mtdswap_init(struct mtdswap_dev *d, unsigned int eblocks,
1271 unsigned int spare_cnt)
1272 {
1273 struct mtd_info *mtd = d->mbd_dev->mtd;
1274 unsigned int i, eblk_bytes, pages, blocks;
1275 int ret = -ENOMEM;
1276
1277 d->mtd = mtd;
1278 d->eblks = eblocks;
1279 d->spare_eblks = spare_cnt;
1280 d->pages_per_eblk = mtd->erasesize >> PAGE_SHIFT;
1281
1282 pages = d->mbd_dev->size;
1283 blocks = eblocks * d->pages_per_eblk;
1284
1285 for (i = 0; i < MTDSWAP_TREE_CNT; i++)
1286 d->trees[i].root = RB_ROOT;
1287
1288 d->page_data = vmalloc(array_size(pages, sizeof(int)));
1289 if (!d->page_data)
1290 goto page_data_fail;
1291
1292 d->revmap = vmalloc(array_size(blocks, sizeof(int)));
1293 if (!d->revmap)
1294 goto revmap_fail;
1295
1296 eblk_bytes = sizeof(struct swap_eb)*d->eblks;
1297 d->eb_data = vzalloc(eblk_bytes);
1298 if (!d->eb_data)
1299 goto eb_data_fail;
1300
1301 for (i = 0; i < pages; i++)
1302 d->page_data[i] = BLOCK_UNDEF;
1303
1304 for (i = 0; i < blocks; i++)
1305 d->revmap[i] = PAGE_UNDEF;
1306
1307 d->page_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1308 if (!d->page_buf)
1309 goto page_buf_fail;
1310
1311 d->oob_buf = kmalloc_array(2, mtd->oobavail, GFP_KERNEL);
1312 if (!d->oob_buf)
1313 goto oob_buf_fail;
1314
1315 mtdswap_scan_eblks(d);
1316
1317 return 0;
1318
1319 oob_buf_fail:
1320 kfree(d->page_buf);
1321 page_buf_fail:
1322 vfree(d->eb_data);
1323 eb_data_fail:
1324 vfree(d->revmap);
1325 revmap_fail:
1326 vfree(d->page_data);
1327 page_data_fail:
1328 printk(KERN_ERR "%s: init failed (%d)\n", MTDSWAP_PREFIX, ret);
1329 return ret;
1330 }
1331
1332 static void mtdswap_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
1333 {
1334 struct mtdswap_dev *d;
1335 struct mtd_blktrans_dev *mbd_dev;
1336 char *parts;
1337 char *this_opt;
1338 unsigned long part;
1339 unsigned int eblocks, eavailable, bad_blocks, spare_cnt;
1340 uint64_t swap_size, use_size, size_limit;
1341 int ret;
1342
1343 parts = &partitions[0];
1344 if (!*parts)
1345 return;
1346
1347 while ((this_opt = strsep(&parts, ",")) != NULL) {
1348 if (kstrtoul(this_opt, 0, &part) < 0)
1349 return;
1350
1351 if (mtd->index == part)
1352 break;
1353 }
1354
1355 if (mtd->index != part)
1356 return;
1357
1358 if (mtd->erasesize < PAGE_SIZE || mtd->erasesize % PAGE_SIZE) {
1359 printk(KERN_ERR "%s: Erase size %u not multiple of PAGE_SIZE "
1360 "%lu\n", MTDSWAP_PREFIX, mtd->erasesize, PAGE_SIZE);
1361 return;
1362 }
1363
1364 if (PAGE_SIZE % mtd->writesize || mtd->writesize > PAGE_SIZE) {
1365 printk(KERN_ERR "%s: PAGE_SIZE %lu not multiple of write size"
1366 " %u\n", MTDSWAP_PREFIX, PAGE_SIZE, mtd->writesize);
1367 return;
1368 }
1369
1370 if (!mtd->oobsize || mtd->oobavail < MTDSWAP_OOBSIZE) {
1371 printk(KERN_ERR "%s: Not enough free bytes in OOB, "
1372 "%d available, %zu needed.\n",
1373 MTDSWAP_PREFIX, mtd->oobavail, MTDSWAP_OOBSIZE);
1374 return;
1375 }
1376
1377 if (spare_eblocks > 100)
1378 spare_eblocks = 100;
1379
1380 use_size = mtd->size;
1381 size_limit = (uint64_t) BLOCK_MAX * PAGE_SIZE;
1382
1383 if (mtd->size > size_limit) {
1384 printk(KERN_WARNING "%s: Device too large. Limiting size to "
1385 "%llu bytes\n", MTDSWAP_PREFIX, size_limit);
1386 use_size = size_limit;
1387 }
1388
1389 eblocks = mtd_div_by_eb(use_size, mtd);
1390 use_size = (uint64_t)eblocks * mtd->erasesize;
1391 bad_blocks = mtdswap_badblocks(mtd, use_size);
1392 eavailable = eblocks - bad_blocks;
1393
1394 if (eavailable < MIN_ERASE_BLOCKS) {
1395 printk(KERN_ERR "%s: Not enough erase blocks. %u available, "
1396 "%d needed\n", MTDSWAP_PREFIX, eavailable,
1397 MIN_ERASE_BLOCKS);
1398 return;
1399 }
1400
1401 spare_cnt = div_u64((uint64_t)eavailable * spare_eblocks, 100);
1402
1403 if (spare_cnt < MIN_SPARE_EBLOCKS)
1404 spare_cnt = MIN_SPARE_EBLOCKS;
1405
1406 if (spare_cnt > eavailable - 1)
1407 spare_cnt = eavailable - 1;
1408
1409 swap_size = (uint64_t)(eavailable - spare_cnt) * mtd->erasesize +
1410 (header ? PAGE_SIZE : 0);
1411
1412 printk(KERN_INFO "%s: Enabling MTD swap on device %lu, size %llu KB, "
1413 "%u spare, %u bad blocks\n",
1414 MTDSWAP_PREFIX, part, swap_size / 1024, spare_cnt, bad_blocks);
1415
1416 d = kzalloc(sizeof(struct mtdswap_dev), GFP_KERNEL);
1417 if (!d)
1418 return;
1419
1420 mbd_dev = kzalloc(sizeof(struct mtd_blktrans_dev), GFP_KERNEL);
1421 if (!mbd_dev) {
1422 kfree(d);
1423 return;
1424 }
1425
1426 d->mbd_dev = mbd_dev;
1427 mbd_dev->priv = d;
1428
1429 mbd_dev->mtd = mtd;
1430 mbd_dev->devnum = mtd->index;
1431 mbd_dev->size = swap_size >> PAGE_SHIFT;
1432 mbd_dev->tr = tr;
1433
1434 if (!(mtd->flags & MTD_WRITEABLE))
1435 mbd_dev->readonly = 1;
1436
1437 if (mtdswap_init(d, eblocks, spare_cnt) < 0)
1438 goto init_failed;
1439
1440 if (add_mtd_blktrans_dev(mbd_dev) < 0)
1441 goto cleanup;
1442
1443 d->dev = disk_to_dev(mbd_dev->disk);
1444
1445 ret = mtdswap_add_debugfs(d);
1446 if (ret < 0)
1447 goto debugfs_failed;
1448
1449 return;
1450
1451 debugfs_failed:
1452 del_mtd_blktrans_dev(mbd_dev);
1453
1454 cleanup:
1455 mtdswap_cleanup(d);
1456
1457 init_failed:
1458 kfree(mbd_dev);
1459 kfree(d);
1460 }
1461
1462 static void mtdswap_remove_dev(struct mtd_blktrans_dev *dev)
1463 {
1464 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1465
1466 del_mtd_blktrans_dev(dev);
1467 mtdswap_cleanup(d);
1468 kfree(d);
1469 }
1470
1471 static struct mtd_blktrans_ops mtdswap_ops = {
1472 .name = "mtdswap",
1473 .major = 0,
1474 .part_bits = 0,
1475 .blksize = PAGE_SIZE,
1476 .flush = mtdswap_flush,
1477 .readsect = mtdswap_readsect,
1478 .writesect = mtdswap_writesect,
1479 .discard = mtdswap_discard,
1480 .background = mtdswap_background,
1481 .add_mtd = mtdswap_add_mtd,
1482 .remove_dev = mtdswap_remove_dev,
1483 .owner = THIS_MODULE,
1484 };
1485
1486 module_mtd_blktrans(mtdswap_ops);
1487
1488 MODULE_LICENSE("GPL");
1489 MODULE_AUTHOR("Jarkko Lavinen <jarkko.lavinen@nokia.com>");
1490 MODULE_DESCRIPTION("Block device access to an MTD suitable for using as "
1491 "swap space");
Linux Kernel