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Linux 4.9.243
[linux/fpc-iii.git] / drivers / mtd / mtdswap.c
blobcb06bdd21a1b57ef73e0d6e3034870bd95d51962
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_TRESHOLD 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 struct dentry *debugfs_root;
143 };
144
145 struct mtdswap_oobdata {
146 __le16 magic;
147 __le32 count;
148 } __packed;
149
150 #define MTDSWAP_MAGIC_CLEAN 0x2095
151 #define MTDSWAP_MAGIC_DIRTY (MTDSWAP_MAGIC_CLEAN + 1)
152 #define MTDSWAP_TYPE_CLEAN 0
153 #define MTDSWAP_TYPE_DIRTY 1
154 #define MTDSWAP_OOBSIZE sizeof(struct mtdswap_oobdata)
155
156 #define MTDSWAP_ERASE_RETRIES 3 /* Before marking erase block bad */
157 #define MTDSWAP_IO_RETRIES 3
158
159 enum {
160 MTDSWAP_SCANNED_CLEAN,
161 MTDSWAP_SCANNED_DIRTY,
162 MTDSWAP_SCANNED_BITFLIP,
163 MTDSWAP_SCANNED_BAD,
164 };
165
166 /*
167 * In the worst case mtdswap_writesect() has allocated the last clean
168 * page from the current block and is then pre-empted by the GC
169 * thread. The thread can consume a full erase block when moving a
170 * block.
171 */
172 #define MIN_SPARE_EBLOCKS 2
173 #define MIN_ERASE_BLOCKS (MIN_SPARE_EBLOCKS + 1)
174
175 #define TREE_ROOT(d, name) (&d->trees[MTDSWAP_ ## name].root)
176 #define TREE_EMPTY(d, name) (TREE_ROOT(d, name)->rb_node == NULL)
177 #define TREE_NONEMPTY(d, name) (!TREE_EMPTY(d, name))
178 #define TREE_COUNT(d, name) (d->trees[MTDSWAP_ ## name].count)
179
180 #define MTDSWAP_MBD_TO_MTDSWAP(dev) ((struct mtdswap_dev *)dev->priv)
181
182 static char partitions[128] = "";
183 module_param_string(partitions, partitions, sizeof(partitions), 0444);
184 MODULE_PARM_DESC(partitions, "MTD partition numbers to use as swap "
185 "partitions=\"1,3,5\"");
186
187 static unsigned int spare_eblocks = 10;
188 module_param(spare_eblocks, uint, 0444);
189 MODULE_PARM_DESC(spare_eblocks, "Percentage of spare erase blocks for "
190 "garbage collection (default 10%)");
191
192 static bool header; /* false */
193 module_param(header, bool, 0444);
194 MODULE_PARM_DESC(header,
195 "Include builtin swap header (default 0, without header)");
196
197 static int mtdswap_gc(struct mtdswap_dev *d, unsigned int background);
198
199 static loff_t mtdswap_eb_offset(struct mtdswap_dev *d, struct swap_eb *eb)
200 {
201 return (loff_t)(eb - d->eb_data) * d->mtd->erasesize;
202 }
203
204 static void mtdswap_eb_detach(struct mtdswap_dev *d, struct swap_eb *eb)
205 {
206 unsigned int oldidx;
207 struct mtdswap_tree *tp;
208
209 if (eb->root) {
210 tp = container_of(eb->root, struct mtdswap_tree, root);
211 oldidx = tp - &d->trees[0];
212
213 d->trees[oldidx].count--;
214 rb_erase(&eb->rb, eb->root);
215 }
216 }
217
218 static void __mtdswap_rb_add(struct rb_root *root, struct swap_eb *eb)
219 {
220 struct rb_node **p, *parent = NULL;
221 struct swap_eb *cur;
222
223 p = &root->rb_node;
224 while (*p) {
225 parent = *p;
226 cur = rb_entry(parent, struct swap_eb, rb);
227 if (eb->erase_count > cur->erase_count)
228 p = &(*p)->rb_right;
229 else
230 p = &(*p)->rb_left;
231 }
232
233 rb_link_node(&eb->rb, parent, p);
234 rb_insert_color(&eb->rb, root);
235 }
236
237 static void mtdswap_rb_add(struct mtdswap_dev *d, struct swap_eb *eb, int idx)
238 {
239 struct rb_root *root;
240
241 if (eb->root == &d->trees[idx].root)
242 return;
243
244 mtdswap_eb_detach(d, eb);
245 root = &d->trees[idx].root;
246 __mtdswap_rb_add(root, eb);
247 eb->root = root;
248 d->trees[idx].count++;
249 }
250
251 static struct rb_node *mtdswap_rb_index(struct rb_root *root, unsigned int idx)
252 {
253 struct rb_node *p;
254 unsigned int i;
255
256 p = rb_first(root);
257 i = 0;
258 while (i < idx && p) {
259 p = rb_next(p);
260 i++;
261 }
262
263 return p;
264 }
265
266 static int mtdswap_handle_badblock(struct mtdswap_dev *d, struct swap_eb *eb)
267 {
268 int ret;
269 loff_t offset;
270
271 d->spare_eblks--;
272 eb->flags |= EBLOCK_BAD;
273 mtdswap_eb_detach(d, eb);
274 eb->root = NULL;
275
276 /* badblocks not supported */
277 if (!mtd_can_have_bb(d->mtd))
278 return 1;
279
280 offset = mtdswap_eb_offset(d, eb);
281 dev_warn(d->dev, "Marking bad block at %08llx\n", offset);
282 ret = mtd_block_markbad(d->mtd, offset);
283
284 if (ret) {
285 dev_warn(d->dev, "Mark block bad failed for block at %08llx "
286 "error %d\n", offset, ret);
287 return ret;
288 }
289
290 return 1;
291
292 }
293
294 static int mtdswap_handle_write_error(struct mtdswap_dev *d, struct swap_eb *eb)
295 {
296 unsigned int marked = eb->flags & EBLOCK_FAILED;
297 struct swap_eb *curr_write = d->curr_write;
298
299 eb->flags |= EBLOCK_FAILED;
300 if (curr_write == eb) {
301 d->curr_write = NULL;
302
303 if (!marked && d->curr_write_pos != 0) {
304 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
305 return 0;
306 }
307 }
308
309 return mtdswap_handle_badblock(d, eb);
310 }
311
312 static int mtdswap_read_oob(struct mtdswap_dev *d, loff_t from,
313 struct mtd_oob_ops *ops)
314 {
315 int ret = mtd_read_oob(d->mtd, from, ops);
316
317 if (mtd_is_bitflip(ret))
318 return ret;
319
320 if (ret) {
321 dev_warn(d->dev, "Read OOB failed %d for block at %08llx\n",
322 ret, from);
323 return ret;
324 }
325
326 if (ops->oobretlen < ops->ooblen) {
327 dev_warn(d->dev, "Read OOB return short read (%zd bytes not "
328 "%zd) for block at %08llx\n",
329 ops->oobretlen, ops->ooblen, from);
330 return -EIO;
331 }
332
333 return 0;
334 }
335
336 static int mtdswap_read_markers(struct mtdswap_dev *d, struct swap_eb *eb)
337 {
338 struct mtdswap_oobdata *data, *data2;
339 int ret;
340 loff_t offset;
341 struct mtd_oob_ops ops;
342
343 offset = mtdswap_eb_offset(d, eb);
344
345 /* Check first if the block is bad. */
346 if (mtd_can_have_bb(d->mtd) && mtd_block_isbad(d->mtd, offset))
347 return MTDSWAP_SCANNED_BAD;
348
349 ops.ooblen = 2 * d->mtd->oobavail;
350 ops.oobbuf = d->oob_buf;
351 ops.ooboffs = 0;
352 ops.datbuf = NULL;
353 ops.mode = MTD_OPS_AUTO_OOB;
354
355 ret = mtdswap_read_oob(d, offset, &ops);
356
357 if (ret && !mtd_is_bitflip(ret))
358 return ret;
359
360 data = (struct mtdswap_oobdata *)d->oob_buf;
361 data2 = (struct mtdswap_oobdata *)
362 (d->oob_buf + d->mtd->oobavail);
363
364 if (le16_to_cpu(data->magic) == MTDSWAP_MAGIC_CLEAN) {
365 eb->erase_count = le32_to_cpu(data->count);
366 if (mtd_is_bitflip(ret))
367 ret = MTDSWAP_SCANNED_BITFLIP;
368 else {
369 if (le16_to_cpu(data2->magic) == MTDSWAP_MAGIC_DIRTY)
370 ret = MTDSWAP_SCANNED_DIRTY;
371 else
372 ret = MTDSWAP_SCANNED_CLEAN;
373 }
374 } else {
375 eb->flags |= EBLOCK_NOMAGIC;
376 ret = MTDSWAP_SCANNED_DIRTY;
377 }
378
379 return ret;
380 }
381
382 static int mtdswap_write_marker(struct mtdswap_dev *d, struct swap_eb *eb,
383 u16 marker)
384 {
385 struct mtdswap_oobdata n;
386 int ret;
387 loff_t offset;
388 struct mtd_oob_ops ops;
389
390 ops.ooboffs = 0;
391 ops.oobbuf = (uint8_t *)&n;
392 ops.mode = MTD_OPS_AUTO_OOB;
393 ops.datbuf = NULL;
394
395 if (marker == MTDSWAP_TYPE_CLEAN) {
396 n.magic = cpu_to_le16(MTDSWAP_MAGIC_CLEAN);
397 n.count = cpu_to_le32(eb->erase_count);
398 ops.ooblen = MTDSWAP_OOBSIZE;
399 offset = mtdswap_eb_offset(d, eb);
400 } else {
401 n.magic = cpu_to_le16(MTDSWAP_MAGIC_DIRTY);
402 ops.ooblen = sizeof(n.magic);
403 offset = mtdswap_eb_offset(d, eb) + d->mtd->writesize;
404 }
405
406 ret = mtd_write_oob(d->mtd, offset, &ops);
407
408 if (ret) {
409 dev_warn(d->dev, "Write OOB failed for block at %08llx "
410 "error %d\n", offset, ret);
411 if (ret == -EIO || mtd_is_eccerr(ret))
412 mtdswap_handle_write_error(d, eb);
413 return ret;
414 }
415
416 if (ops.oobretlen != ops.ooblen) {
417 dev_warn(d->dev, "Short OOB write for block at %08llx: "
418 "%zd not %zd\n",
419 offset, ops.oobretlen, ops.ooblen);
420 return ret;
421 }
422
423 return 0;
424 }
425
426 /*
427 * Are there any erase blocks without MAGIC_CLEAN header, presumably
428 * because power was cut off after erase but before header write? We
429 * need to guestimate the erase count.
430 */
431 static void mtdswap_check_counts(struct mtdswap_dev *d)
432 {
433 struct rb_root hist_root = RB_ROOT;
434 struct rb_node *medrb;
435 struct swap_eb *eb;
436 unsigned int i, cnt, median;
437
438 cnt = 0;
439 for (i = 0; i < d->eblks; i++) {
440 eb = d->eb_data + i;
441
442 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_BAD | EBLOCK_READERR))
443 continue;
444
445 __mtdswap_rb_add(&hist_root, eb);
446 cnt++;
447 }
448
449 if (cnt == 0)
450 return;
451
452 medrb = mtdswap_rb_index(&hist_root, cnt / 2);
453 median = rb_entry(medrb, struct swap_eb, rb)->erase_count;
454
455 d->max_erase_count = MTDSWAP_ECNT_MAX(&hist_root);
456
457 for (i = 0; i < d->eblks; i++) {
458 eb = d->eb_data + i;
459
460 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_READERR))
461 eb->erase_count = median;
462
463 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_BAD | EBLOCK_READERR))
464 continue;
465
466 rb_erase(&eb->rb, &hist_root);
467 }
468 }
469
470 static void mtdswap_scan_eblks(struct mtdswap_dev *d)
471 {
472 int status;
473 unsigned int i, idx;
474 struct swap_eb *eb;
475
476 for (i = 0; i < d->eblks; i++) {
477 eb = d->eb_data + i;
478
479 status = mtdswap_read_markers(d, eb);
480 if (status < 0)
481 eb->flags |= EBLOCK_READERR;
482 else if (status == MTDSWAP_SCANNED_BAD) {
483 eb->flags |= EBLOCK_BAD;
484 continue;
485 }
486
487 switch (status) {
488 case MTDSWAP_SCANNED_CLEAN:
489 idx = MTDSWAP_CLEAN;
490 break;
491 case MTDSWAP_SCANNED_DIRTY:
492 case MTDSWAP_SCANNED_BITFLIP:
493 idx = MTDSWAP_DIRTY;
494 break;
495 default:
496 idx = MTDSWAP_FAILING;
497 }
498
499 eb->flags |= (idx << EBLOCK_IDX_SHIFT);
500 }
501
502 mtdswap_check_counts(d);
503
504 for (i = 0; i < d->eblks; i++) {
505 eb = d->eb_data + i;
506
507 if (eb->flags & EBLOCK_BAD)
508 continue;
509
510 idx = eb->flags >> EBLOCK_IDX_SHIFT;
511 mtdswap_rb_add(d, eb, idx);
512 }
513 }
514
515 /*
516 * Place eblk into a tree corresponding to its number of active blocks
517 * it contains.
518 */
519 static void mtdswap_store_eb(struct mtdswap_dev *d, struct swap_eb *eb)
520 {
521 unsigned int weight = eb->active_count;
522 unsigned int maxweight = d->pages_per_eblk;
523
524 if (eb == d->curr_write)
525 return;
526
527 if (eb->flags & EBLOCK_BITFLIP)
528 mtdswap_rb_add(d, eb, MTDSWAP_BITFLIP);
529 else if (eb->flags & (EBLOCK_READERR | EBLOCK_FAILED))
530 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
531 if (weight == maxweight)
532 mtdswap_rb_add(d, eb, MTDSWAP_USED);
533 else if (weight == 0)
534 mtdswap_rb_add(d, eb, MTDSWAP_DIRTY);
535 else if (weight > (maxweight/2))
536 mtdswap_rb_add(d, eb, MTDSWAP_LOWFRAG);
537 else
538 mtdswap_rb_add(d, eb, MTDSWAP_HIFRAG);
539 }
540
541
542 static void mtdswap_erase_callback(struct erase_info *done)
543 {
544 wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
545 wake_up(wait_q);
546 }
547
548 static int mtdswap_erase_block(struct mtdswap_dev *d, struct swap_eb *eb)
549 {
550 struct mtd_info *mtd = d->mtd;
551 struct erase_info erase;
552 wait_queue_head_t wq;
553 unsigned int retries = 0;
554 int ret;
555
556 eb->erase_count++;
557 if (eb->erase_count > d->max_erase_count)
558 d->max_erase_count = eb->erase_count;
559
560 retry:
561 init_waitqueue_head(&wq);
562 memset(&erase, 0, sizeof(struct erase_info));
563
564 erase.mtd = mtd;
565 erase.callback = mtdswap_erase_callback;
566 erase.addr = mtdswap_eb_offset(d, eb);
567 erase.len = mtd->erasesize;
568 erase.priv = (u_long)&wq;
569
570 ret = mtd_erase(mtd, &erase);
571 if (ret) {
572 if (retries++ < MTDSWAP_ERASE_RETRIES) {
573 dev_warn(d->dev,
574 "erase of erase block %#llx on %s failed",
575 erase.addr, mtd->name);
576 yield();
577 goto retry;
578 }
579
580 dev_err(d->dev, "Cannot erase erase block %#llx on %s\n",
581 erase.addr, mtd->name);
582
583 mtdswap_handle_badblock(d, eb);
584 return -EIO;
585 }
586
587 ret = wait_event_interruptible(wq, erase.state == MTD_ERASE_DONE ||
588 erase.state == MTD_ERASE_FAILED);
589 if (ret) {
590 dev_err(d->dev, "Interrupted erase block %#llx erassure on %s",
591 erase.addr, mtd->name);
592 return -EINTR;
593 }
594
595 if (erase.state == MTD_ERASE_FAILED) {
596 if (retries++ < MTDSWAP_ERASE_RETRIES) {
597 dev_warn(d->dev,
598 "erase of erase block %#llx on %s failed",
599 erase.addr, mtd->name);
600 yield();
601 goto retry;
602 }
603
604 mtdswap_handle_badblock(d, eb);
605 return -EIO;
606 }
607
608 return 0;
609 }
610
611 static int mtdswap_map_free_block(struct mtdswap_dev *d, unsigned int page,
612 unsigned int *block)
613 {
614 int ret;
615 struct swap_eb *old_eb = d->curr_write;
616 struct rb_root *clean_root;
617 struct swap_eb *eb;
618
619 if (old_eb == NULL || d->curr_write_pos >= d->pages_per_eblk) {
620 do {
621 if (TREE_EMPTY(d, CLEAN))
622 return -ENOSPC;
623
624 clean_root = TREE_ROOT(d, CLEAN);
625 eb = rb_entry(rb_first(clean_root), struct swap_eb, rb);
626 rb_erase(&eb->rb, clean_root);
627 eb->root = NULL;
628 TREE_COUNT(d, CLEAN)--;
629
630 ret = mtdswap_write_marker(d, eb, MTDSWAP_TYPE_DIRTY);
631 } while (ret == -EIO || mtd_is_eccerr(ret));
632
633 if (ret)
634 return ret;
635
636 d->curr_write_pos = 0;
637 d->curr_write = eb;
638 if (old_eb)
639 mtdswap_store_eb(d, old_eb);
640 }
641
642 *block = (d->curr_write - d->eb_data) * d->pages_per_eblk +
643 d->curr_write_pos;
644
645 d->curr_write->active_count++;
646 d->revmap[*block] = page;
647 d->curr_write_pos++;
648
649 return 0;
650 }
651
652 static unsigned int mtdswap_free_page_cnt(struct mtdswap_dev *d)
653 {
654 return TREE_COUNT(d, CLEAN) * d->pages_per_eblk +
655 d->pages_per_eblk - d->curr_write_pos;
656 }
657
658 static unsigned int mtdswap_enough_free_pages(struct mtdswap_dev *d)
659 {
660 return mtdswap_free_page_cnt(d) > d->pages_per_eblk;
661 }
662
663 static int mtdswap_write_block(struct mtdswap_dev *d, char *buf,
664 unsigned int page, unsigned int *bp, int gc_context)
665 {
666 struct mtd_info *mtd = d->mtd;
667 struct swap_eb *eb;
668 size_t retlen;
669 loff_t writepos;
670 int ret;
671
672 retry:
673 if (!gc_context)
674 while (!mtdswap_enough_free_pages(d))
675 if (mtdswap_gc(d, 0) > 0)
676 return -ENOSPC;
677
678 ret = mtdswap_map_free_block(d, page, bp);
679 eb = d->eb_data + (*bp / d->pages_per_eblk);
680
681 if (ret == -EIO || mtd_is_eccerr(ret)) {
682 d->curr_write = NULL;
683 eb->active_count--;
684 d->revmap[*bp] = PAGE_UNDEF;
685 goto retry;
686 }
687
688 if (ret < 0)
689 return ret;
690
691 writepos = (loff_t)*bp << PAGE_SHIFT;
692 ret = mtd_write(mtd, writepos, PAGE_SIZE, &retlen, buf);
693 if (ret == -EIO || mtd_is_eccerr(ret)) {
694 d->curr_write_pos--;
695 eb->active_count--;
696 d->revmap[*bp] = PAGE_UNDEF;
697 mtdswap_handle_write_error(d, eb);
698 goto retry;
699 }
700
701 if (ret < 0) {
702 dev_err(d->dev, "Write to MTD device failed: %d (%zd written)",
703 ret, retlen);
704 goto err;
705 }
706
707 if (retlen != PAGE_SIZE) {
708 dev_err(d->dev, "Short write to MTD device: %zd written",
709 retlen);
710 ret = -EIO;
711 goto err;
712 }
713
714 return ret;
715
716 err:
717 d->curr_write_pos--;
718 eb->active_count--;
719 d->revmap[*bp] = PAGE_UNDEF;
720
721 return ret;
722 }
723
724 static int mtdswap_move_block(struct mtdswap_dev *d, unsigned int oldblock,
725 unsigned int *newblock)
726 {
727 struct mtd_info *mtd = d->mtd;
728 struct swap_eb *eb, *oldeb;
729 int ret;
730 size_t retlen;
731 unsigned int page, retries;
732 loff_t readpos;
733
734 page = d->revmap[oldblock];
735 readpos = (loff_t) oldblock << PAGE_SHIFT;
736 retries = 0;
737
738 retry:
739 ret = mtd_read(mtd, readpos, PAGE_SIZE, &retlen, d->page_buf);
740
741 if (ret < 0 && !mtd_is_bitflip(ret)) {
742 oldeb = d->eb_data + oldblock / d->pages_per_eblk;
743 oldeb->flags |= EBLOCK_READERR;
744
745 dev_err(d->dev, "Read Error: %d (block %u)\n", ret,
746 oldblock);
747 retries++;
748 if (retries < MTDSWAP_IO_RETRIES)
749 goto retry;
750
751 goto read_error;
752 }
753
754 if (retlen != PAGE_SIZE) {
755 dev_err(d->dev, "Short read: %zd (block %u)\n", retlen,
756 oldblock);
757 ret = -EIO;
758 goto read_error;
759 }
760
761 ret = mtdswap_write_block(d, d->page_buf, page, newblock, 1);
762 if (ret < 0) {
763 d->page_data[page] = BLOCK_ERROR;
764 dev_err(d->dev, "Write error: %d\n", ret);
765 return ret;
766 }
767
768 eb = d->eb_data + *newblock / d->pages_per_eblk;
769 d->page_data[page] = *newblock;
770 d->revmap[oldblock] = PAGE_UNDEF;
771 eb = d->eb_data + oldblock / d->pages_per_eblk;
772 eb->active_count--;
773
774 return 0;
775
776 read_error:
777 d->page_data[page] = BLOCK_ERROR;
778 d->revmap[oldblock] = PAGE_UNDEF;
779 return ret;
780 }
781
782 static int mtdswap_gc_eblock(struct mtdswap_dev *d, struct swap_eb *eb)
783 {
784 unsigned int i, block, eblk_base, newblock;
785 int ret, errcode;
786
787 errcode = 0;
788 eblk_base = (eb - d->eb_data) * d->pages_per_eblk;
789
790 for (i = 0; i < d->pages_per_eblk; i++) {
791 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
792 return -ENOSPC;
793
794 block = eblk_base + i;
795 if (d->revmap[block] == PAGE_UNDEF)
796 continue;
797
798 ret = mtdswap_move_block(d, block, &newblock);
799 if (ret < 0 && !errcode)
800 errcode = ret;
801 }
802
803 return errcode;
804 }
805
806 static int __mtdswap_choose_gc_tree(struct mtdswap_dev *d)
807 {
808 int idx, stopat;
809
810 if (TREE_COUNT(d, CLEAN) < LOW_FRAG_GC_TRESHOLD)
811 stopat = MTDSWAP_LOWFRAG;
812 else
813 stopat = MTDSWAP_HIFRAG;
814
815 for (idx = MTDSWAP_BITFLIP; idx >= stopat; idx--)
816 if (d->trees[idx].root.rb_node != NULL)
817 return idx;
818
819 return -1;
820 }
821
822 static int mtdswap_wlfreq(unsigned int maxdiff)
823 {
824 unsigned int h, x, y, dist, base;
825
826 /*
827 * Calculate linear ramp down from f1 to f2 when maxdiff goes from
828 * MAX_ERASE_DIFF to MAX_ERASE_DIFF + COLLECT_NONDIRTY_BASE. Similar
829 * to triangle with height f1 - f1 and width COLLECT_NONDIRTY_BASE.
830 */
831
832 dist = maxdiff - MAX_ERASE_DIFF;
833 if (dist > COLLECT_NONDIRTY_BASE)
834 dist = COLLECT_NONDIRTY_BASE;
835
836 /*
837 * Modelling the slop as right angular triangle with base
838 * COLLECT_NONDIRTY_BASE and height freq1 - freq2. The ratio y/x is
839 * equal to the ratio h/base.
840 */
841 h = COLLECT_NONDIRTY_FREQ1 - COLLECT_NONDIRTY_FREQ2;
842 base = COLLECT_NONDIRTY_BASE;
843
844 x = dist - base;
845 y = (x * h + base / 2) / base;
846
847 return COLLECT_NONDIRTY_FREQ2 + y;
848 }
849
850 static int mtdswap_choose_wl_tree(struct mtdswap_dev *d)
851 {
852 static unsigned int pick_cnt;
853 unsigned int i, idx = -1, wear, max;
854 struct rb_root *root;
855
856 max = 0;
857 for (i = 0; i <= MTDSWAP_DIRTY; i++) {
858 root = &d->trees[i].root;
859 if (root->rb_node == NULL)
860 continue;
861
862 wear = d->max_erase_count - MTDSWAP_ECNT_MIN(root);
863 if (wear > max) {
864 max = wear;
865 idx = i;
866 }
867 }
868
869 if (max > MAX_ERASE_DIFF && pick_cnt >= mtdswap_wlfreq(max) - 1) {
870 pick_cnt = 0;
871 return idx;
872 }
873
874 pick_cnt++;
875 return -1;
876 }
877
878 static int mtdswap_choose_gc_tree(struct mtdswap_dev *d,
879 unsigned int background)
880 {
881 int idx;
882
883 if (TREE_NONEMPTY(d, FAILING) &&
884 (background || (TREE_EMPTY(d, CLEAN) && TREE_EMPTY(d, DIRTY))))
885 return MTDSWAP_FAILING;
886
887 idx = mtdswap_choose_wl_tree(d);
888 if (idx >= MTDSWAP_CLEAN)
889 return idx;
890
891 return __mtdswap_choose_gc_tree(d);
892 }
893
894 static struct swap_eb *mtdswap_pick_gc_eblk(struct mtdswap_dev *d,
895 unsigned int background)
896 {
897 struct rb_root *rp = NULL;
898 struct swap_eb *eb = NULL;
899 int idx;
900
901 if (background && TREE_COUNT(d, CLEAN) > CLEAN_BLOCK_THRESHOLD &&
902 TREE_EMPTY(d, DIRTY) && TREE_EMPTY(d, FAILING))
903 return NULL;
904
905 idx = mtdswap_choose_gc_tree(d, background);
906 if (idx < 0)
907 return NULL;
908
909 rp = &d->trees[idx].root;
910 eb = rb_entry(rb_first(rp), struct swap_eb, rb);
911
912 rb_erase(&eb->rb, rp);
913 eb->root = NULL;
914 d->trees[idx].count--;
915 return eb;
916 }
917
918 static unsigned int mtdswap_test_patt(unsigned int i)
919 {
920 return i % 2 ? 0x55555555 : 0xAAAAAAAA;
921 }
922
923 static unsigned int mtdswap_eblk_passes(struct mtdswap_dev *d,
924 struct swap_eb *eb)
925 {
926 struct mtd_info *mtd = d->mtd;
927 unsigned int test, i, j, patt, mtd_pages;
928 loff_t base, pos;
929 unsigned int *p1 = (unsigned int *)d->page_buf;
930 unsigned char *p2 = (unsigned char *)d->oob_buf;
931 struct mtd_oob_ops ops;
932 int ret;
933
934 ops.mode = MTD_OPS_AUTO_OOB;
935 ops.len = mtd->writesize;
936 ops.ooblen = mtd->oobavail;
937 ops.ooboffs = 0;
938 ops.datbuf = d->page_buf;
939 ops.oobbuf = d->oob_buf;
940 base = mtdswap_eb_offset(d, eb);
941 mtd_pages = d->pages_per_eblk * PAGE_SIZE / mtd->writesize;
942
943 for (test = 0; test < 2; test++) {
944 pos = base;
945 for (i = 0; i < mtd_pages; i++) {
946 patt = mtdswap_test_patt(test + i);
947 memset(d->page_buf, patt, mtd->writesize);
948 memset(d->oob_buf, patt, mtd->oobavail);
949 ret = mtd_write_oob(mtd, pos, &ops);
950 if (ret)
951 goto error;
952
953 pos += mtd->writesize;
954 }
955
956 pos = base;
957 for (i = 0; i < mtd_pages; i++) {
958 ret = mtd_read_oob(mtd, pos, &ops);
959 if (ret)
960 goto error;
961
962 patt = mtdswap_test_patt(test + i);
963 for (j = 0; j < mtd->writesize/sizeof(int); j++)
964 if (p1[j] != patt)
965 goto error;
966
967 for (j = 0; j < mtd->oobavail; j++)
968 if (p2[j] != (unsigned char)patt)
969 goto error;
970
971 pos += mtd->writesize;
972 }
973
974 ret = mtdswap_erase_block(d, eb);
975 if (ret)
976 goto error;
977 }
978
979 eb->flags &= ~EBLOCK_READERR;
980 return 1;
981
982 error:
983 mtdswap_handle_badblock(d, eb);
984 return 0;
985 }
986
987 static int mtdswap_gc(struct mtdswap_dev *d, unsigned int background)
988 {
989 struct swap_eb *eb;
990 int ret;
991
992 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
993 return 1;
994
995 eb = mtdswap_pick_gc_eblk(d, background);
996 if (!eb)
997 return 1;
998
999 ret = mtdswap_gc_eblock(d, eb);
1000 if (ret == -ENOSPC)
1001 return 1;
1002
1003 if (eb->flags & EBLOCK_FAILED) {
1004 mtdswap_handle_badblock(d, eb);
1005 return 0;
1006 }
1007
1008 eb->flags &= ~EBLOCK_BITFLIP;
1009 ret = mtdswap_erase_block(d, eb);
1010 if ((eb->flags & EBLOCK_READERR) &&
1011 (ret || !mtdswap_eblk_passes(d, eb)))
1012 return 0;
1013
1014 if (ret == 0)
1015 ret = mtdswap_write_marker(d, eb, MTDSWAP_TYPE_CLEAN);
1016
1017 if (ret == 0)
1018 mtdswap_rb_add(d, eb, MTDSWAP_CLEAN);
1019 else if (ret != -EIO && !mtd_is_eccerr(ret))
1020 mtdswap_rb_add(d, eb, MTDSWAP_DIRTY);
1021
1022 return 0;
1023 }
1024
1025 static void mtdswap_background(struct mtd_blktrans_dev *dev)
1026 {
1027 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1028 int ret;
1029
1030 while (1) {
1031 ret = mtdswap_gc(d, 1);
1032 if (ret || mtd_blktrans_cease_background(dev))
1033 return;
1034 }
1035 }
1036
1037 static void mtdswap_cleanup(struct mtdswap_dev *d)
1038 {
1039 vfree(d->eb_data);
1040 vfree(d->revmap);
1041 vfree(d->page_data);
1042 kfree(d->oob_buf);
1043 kfree(d->page_buf);
1044 }
1045
1046 static int mtdswap_flush(struct mtd_blktrans_dev *dev)
1047 {
1048 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1049
1050 mtd_sync(d->mtd);
1051 return 0;
1052 }
1053
1054 static unsigned int mtdswap_badblocks(struct mtd_info *mtd, uint64_t size)
1055 {
1056 loff_t offset;
1057 unsigned int badcnt;
1058
1059 badcnt = 0;
1060
1061 if (mtd_can_have_bb(mtd))
1062 for (offset = 0; offset < size; offset += mtd->erasesize)
1063 if (mtd_block_isbad(mtd, offset))
1064 badcnt++;
1065
1066 return badcnt;
1067 }
1068
1069 static int mtdswap_writesect(struct mtd_blktrans_dev *dev,
1070 unsigned long page, char *buf)
1071 {
1072 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1073 unsigned int newblock, mapped;
1074 struct swap_eb *eb;
1075 int ret;
1076
1077 d->sect_write_count++;
1078
1079 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
1080 return -ENOSPC;
1081
1082 if (header) {
1083 /* Ignore writes to the header page */
1084 if (unlikely(page == 0))
1085 return 0;
1086
1087 page--;
1088 }
1089
1090 mapped = d->page_data[page];
1091 if (mapped <= BLOCK_MAX) {
1092 eb = d->eb_data + (mapped / d->pages_per_eblk);
1093 eb->active_count--;
1094 mtdswap_store_eb(d, eb);
1095 d->page_data[page] = BLOCK_UNDEF;
1096 d->revmap[mapped] = PAGE_UNDEF;
1097 }
1098
1099 ret = mtdswap_write_block(d, buf, page, &newblock, 0);
1100 d->mtd_write_count++;
1101
1102 if (ret < 0)
1103 return ret;
1104
1105 eb = d->eb_data + (newblock / d->pages_per_eblk);
1106 d->page_data[page] = newblock;
1107
1108 return 0;
1109 }
1110
1111 /* Provide a dummy swap header for the kernel */
1112 static int mtdswap_auto_header(struct mtdswap_dev *d, char *buf)
1113 {
1114 union swap_header *hd = (union swap_header *)(buf);
1115
1116 memset(buf, 0, PAGE_SIZE - 10);
1117
1118 hd->info.version = 1;
1119 hd->info.last_page = d->mbd_dev->size - 1;
1120 hd->info.nr_badpages = 0;
1121
1122 memcpy(buf + PAGE_SIZE - 10, "SWAPSPACE2", 10);
1123
1124 return 0;
1125 }
1126
1127 static int mtdswap_readsect(struct mtd_blktrans_dev *dev,
1128 unsigned long page, char *buf)
1129 {
1130 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1131 struct mtd_info *mtd = d->mtd;
1132 unsigned int realblock, retries;
1133 loff_t readpos;
1134 struct swap_eb *eb;
1135 size_t retlen;
1136 int ret;
1137
1138 d->sect_read_count++;
1139
1140 if (header) {
1141 if (unlikely(page == 0))
1142 return mtdswap_auto_header(d, buf);
1143
1144 page--;
1145 }
1146
1147 realblock = d->page_data[page];
1148 if (realblock > BLOCK_MAX) {
1149 memset(buf, 0x0, PAGE_SIZE);
1150 if (realblock == BLOCK_UNDEF)
1151 return 0;
1152 else
1153 return -EIO;
1154 }
1155
1156 eb = d->eb_data + (realblock / d->pages_per_eblk);
1157 BUG_ON(d->revmap[realblock] == PAGE_UNDEF);
1158
1159 readpos = (loff_t)realblock << PAGE_SHIFT;
1160 retries = 0;
1161
1162 retry:
1163 ret = mtd_read(mtd, readpos, PAGE_SIZE, &retlen, buf);
1164
1165 d->mtd_read_count++;
1166 if (mtd_is_bitflip(ret)) {
1167 eb->flags |= EBLOCK_BITFLIP;
1168 mtdswap_rb_add(d, eb, MTDSWAP_BITFLIP);
1169 ret = 0;
1170 }
1171
1172 if (ret < 0) {
1173 dev_err(d->dev, "Read error %d\n", ret);
1174 eb->flags |= EBLOCK_READERR;
1175 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
1176 retries++;
1177 if (retries < MTDSWAP_IO_RETRIES)
1178 goto retry;
1179
1180 return ret;
1181 }
1182
1183 if (retlen != PAGE_SIZE) {
1184 dev_err(d->dev, "Short read %zd\n", retlen);
1185 return -EIO;
1186 }
1187
1188 return 0;
1189 }
1190
1191 static int mtdswap_discard(struct mtd_blktrans_dev *dev, unsigned long first,
1192 unsigned nr_pages)
1193 {
1194 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1195 unsigned long page;
1196 struct swap_eb *eb;
1197 unsigned int mapped;
1198
1199 d->discard_count++;
1200
1201 for (page = first; page < first + nr_pages; page++) {
1202 mapped = d->page_data[page];
1203 if (mapped <= BLOCK_MAX) {
1204 eb = d->eb_data + (mapped / d->pages_per_eblk);
1205 eb->active_count--;
1206 mtdswap_store_eb(d, eb);
1207 d->page_data[page] = BLOCK_UNDEF;
1208 d->revmap[mapped] = PAGE_UNDEF;
1209 d->discard_page_count++;
1210 } else if (mapped == BLOCK_ERROR) {
1211 d->page_data[page] = BLOCK_UNDEF;
1212 d->discard_page_count++;
1213 }
1214 }
1215
1216 return 0;
1217 }
1218
1219 static int mtdswap_show(struct seq_file *s, void *data)
1220 {
1221 struct mtdswap_dev *d = (struct mtdswap_dev *) s->private;
1222 unsigned long sum;
1223 unsigned int count[MTDSWAP_TREE_CNT];
1224 unsigned int min[MTDSWAP_TREE_CNT];
1225 unsigned int max[MTDSWAP_TREE_CNT];
1226 unsigned int i, cw = 0, cwp = 0, cwecount = 0, bb_cnt, mapped, pages;
1227 uint64_t use_size;
1228 char *name[] = {"clean", "used", "low", "high", "dirty", "bitflip",
1229 "failing"};
1230
1231 mutex_lock(&d->mbd_dev->lock);
1232
1233 for (i = 0; i < MTDSWAP_TREE_CNT; i++) {
1234 struct rb_root *root = &d->trees[i].root;
1235
1236 if (root->rb_node) {
1237 count[i] = d->trees[i].count;
1238 min[i] = rb_entry(rb_first(root), struct swap_eb,
1239 rb)->erase_count;
1240 max[i] = rb_entry(rb_last(root), struct swap_eb,
1241 rb)->erase_count;
1242 } else
1243 count[i] = 0;
1244 }
1245
1246 if (d->curr_write) {
1247 cw = 1;
1248 cwp = d->curr_write_pos;
1249 cwecount = d->curr_write->erase_count;
1250 }
1251
1252 sum = 0;
1253 for (i = 0; i < d->eblks; i++)
1254 sum += d->eb_data[i].erase_count;
1255
1256 use_size = (uint64_t)d->eblks * d->mtd->erasesize;
1257 bb_cnt = mtdswap_badblocks(d->mtd, use_size);
1258
1259 mapped = 0;
1260 pages = d->mbd_dev->size;
1261 for (i = 0; i < pages; i++)
1262 if (d->page_data[i] != BLOCK_UNDEF)
1263 mapped++;
1264
1265 mutex_unlock(&d->mbd_dev->lock);
1266
1267 for (i = 0; i < MTDSWAP_TREE_CNT; i++) {
1268 if (!count[i])
1269 continue;
1270
1271 if (min[i] != max[i])
1272 seq_printf(s, "%s:\t%5d erase blocks, erased min %d, "
1273 "max %d times\n",
1274 name[i], count[i], min[i], max[i]);
1275 else
1276 seq_printf(s, "%s:\t%5d erase blocks, all erased %d "
1277 "times\n", name[i], count[i], min[i]);
1278 }
1279
1280 if (bb_cnt)
1281 seq_printf(s, "bad:\t%5u erase blocks\n", bb_cnt);
1282
1283 if (cw)
1284 seq_printf(s, "current erase block: %u pages used, %u free, "
1285 "erased %u times\n",
1286 cwp, d->pages_per_eblk - cwp, cwecount);
1287
1288 seq_printf(s, "total erasures: %lu\n", sum);
1289
1290 seq_puts(s, "\n");
1291
1292 seq_printf(s, "mtdswap_readsect count: %llu\n", d->sect_read_count);
1293 seq_printf(s, "mtdswap_writesect count: %llu\n", d->sect_write_count);
1294 seq_printf(s, "mtdswap_discard count: %llu\n", d->discard_count);
1295 seq_printf(s, "mtd read count: %llu\n", d->mtd_read_count);
1296 seq_printf(s, "mtd write count: %llu\n", d->mtd_write_count);
1297 seq_printf(s, "discarded pages count: %llu\n", d->discard_page_count);
1298
1299 seq_puts(s, "\n");
1300 seq_printf(s, "total pages: %u\n", pages);
1301 seq_printf(s, "pages mapped: %u\n", mapped);
1302
1303 return 0;
1304 }
1305
1306 static int mtdswap_open(struct inode *inode, struct file *file)
1307 {
1308 return single_open(file, mtdswap_show, inode->i_private);
1309 }
1310
1311 static const struct file_operations mtdswap_fops = {
1312 .open = mtdswap_open,
1313 .read = seq_read,
1314 .llseek = seq_lseek,
1315 .release = single_release,
1316 };
1317
1318 static int mtdswap_add_debugfs(struct mtdswap_dev *d)
1319 {
1320 struct gendisk *gd = d->mbd_dev->disk;
1321 struct device *dev = disk_to_dev(gd);
1322
1323 struct dentry *root;
1324 struct dentry *dent;
1325
1326 root = debugfs_create_dir(gd->disk_name, NULL);
1327 if (IS_ERR(root))
1328 return 0;
1329
1330 if (!root) {
1331 dev_err(dev, "failed to initialize debugfs\n");
1332 return -1;
1333 }
1334
1335 d->debugfs_root = root;
1336
1337 dent = debugfs_create_file("stats", S_IRUSR, root, d,
1338 &mtdswap_fops);
1339 if (!dent) {
1340 dev_err(d->dev, "debugfs_create_file failed\n");
1341 debugfs_remove_recursive(root);
1342 d->debugfs_root = NULL;
1343 return -1;
1344 }
1345
1346 return 0;
1347 }
1348
1349 static int mtdswap_init(struct mtdswap_dev *d, unsigned int eblocks,
1350 unsigned int spare_cnt)
1351 {
1352 struct mtd_info *mtd = d->mbd_dev->mtd;
1353 unsigned int i, eblk_bytes, pages, blocks;
1354 int ret = -ENOMEM;
1355
1356 d->mtd = mtd;
1357 d->eblks = eblocks;
1358 d->spare_eblks = spare_cnt;
1359 d->pages_per_eblk = mtd->erasesize >> PAGE_SHIFT;
1360
1361 pages = d->mbd_dev->size;
1362 blocks = eblocks * d->pages_per_eblk;
1363
1364 for (i = 0; i < MTDSWAP_TREE_CNT; i++)
1365 d->trees[i].root = RB_ROOT;
1366
1367 d->page_data = vmalloc(sizeof(int)*pages);
1368 if (!d->page_data)
1369 goto page_data_fail;
1370
1371 d->revmap = vmalloc(sizeof(int)*blocks);
1372 if (!d->revmap)
1373 goto revmap_fail;
1374
1375 eblk_bytes = sizeof(struct swap_eb)*d->eblks;
1376 d->eb_data = vzalloc(eblk_bytes);
1377 if (!d->eb_data)
1378 goto eb_data_fail;
1379
1380 for (i = 0; i < pages; i++)
1381 d->page_data[i] = BLOCK_UNDEF;
1382
1383 for (i = 0; i < blocks; i++)
1384 d->revmap[i] = PAGE_UNDEF;
1385
1386 d->page_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1387 if (!d->page_buf)
1388 goto page_buf_fail;
1389
1390 d->oob_buf = kmalloc(2 * mtd->oobavail, GFP_KERNEL);
1391 if (!d->oob_buf)
1392 goto oob_buf_fail;
1393
1394 mtdswap_scan_eblks(d);
1395
1396 return 0;
1397
1398 oob_buf_fail:
1399 kfree(d->page_buf);
1400 page_buf_fail:
1401 vfree(d->eb_data);
1402 eb_data_fail:
1403 vfree(d->revmap);
1404 revmap_fail:
1405 vfree(d->page_data);
1406 page_data_fail:
1407 printk(KERN_ERR "%s: init failed (%d)\n", MTDSWAP_PREFIX, ret);
1408 return ret;
1409 }
1410
1411 static void mtdswap_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
1412 {
1413 struct mtdswap_dev *d;
1414 struct mtd_blktrans_dev *mbd_dev;
1415 char *parts;
1416 char *this_opt;
1417 unsigned long part;
1418 unsigned int eblocks, eavailable, bad_blocks, spare_cnt;
1419 uint64_t swap_size, use_size, size_limit;
1420 int ret;
1421
1422 parts = &partitions[0];
1423 if (!*parts)
1424 return;
1425
1426 while ((this_opt = strsep(&parts, ",")) != NULL) {
1427 if (kstrtoul(this_opt, 0, &part) < 0)
1428 return;
1429
1430 if (mtd->index == part)
1431 break;
1432 }
1433
1434 if (mtd->index != part)
1435 return;
1436
1437 if (mtd->erasesize < PAGE_SIZE || mtd->erasesize % PAGE_SIZE) {
1438 printk(KERN_ERR "%s: Erase size %u not multiple of PAGE_SIZE "
1439 "%lu\n", MTDSWAP_PREFIX, mtd->erasesize, PAGE_SIZE);
1440 return;
1441 }
1442
1443 if (PAGE_SIZE % mtd->writesize || mtd->writesize > PAGE_SIZE) {
1444 printk(KERN_ERR "%s: PAGE_SIZE %lu not multiple of write size"
1445 " %u\n", MTDSWAP_PREFIX, PAGE_SIZE, mtd->writesize);
1446 return;
1447 }
1448
1449 if (!mtd->oobsize || mtd->oobavail < MTDSWAP_OOBSIZE) {
1450 printk(KERN_ERR "%s: Not enough free bytes in OOB, "
1451 "%d available, %zu needed.\n",
1452 MTDSWAP_PREFIX, mtd->oobavail, MTDSWAP_OOBSIZE);
1453 return;
1454 }
1455
1456 if (spare_eblocks > 100)
1457 spare_eblocks = 100;
1458
1459 use_size = mtd->size;
1460 size_limit = (uint64_t) BLOCK_MAX * PAGE_SIZE;
1461
1462 if (mtd->size > size_limit) {
1463 printk(KERN_WARNING "%s: Device too large. Limiting size to "
1464 "%llu bytes\n", MTDSWAP_PREFIX, size_limit);
1465 use_size = size_limit;
1466 }
1467
1468 eblocks = mtd_div_by_eb(use_size, mtd);
1469 use_size = (uint64_t)eblocks * mtd->erasesize;
1470 bad_blocks = mtdswap_badblocks(mtd, use_size);
1471 eavailable = eblocks - bad_blocks;
1472
1473 if (eavailable < MIN_ERASE_BLOCKS) {
1474 printk(KERN_ERR "%s: Not enough erase blocks. %u available, "
1475 "%d needed\n", MTDSWAP_PREFIX, eavailable,
1476 MIN_ERASE_BLOCKS);
1477 return;
1478 }
1479
1480 spare_cnt = div_u64((uint64_t)eavailable * spare_eblocks, 100);
1481
1482 if (spare_cnt < MIN_SPARE_EBLOCKS)
1483 spare_cnt = MIN_SPARE_EBLOCKS;
1484
1485 if (spare_cnt > eavailable - 1)
1486 spare_cnt = eavailable - 1;
1487
1488 swap_size = (uint64_t)(eavailable - spare_cnt) * mtd->erasesize +
1489 (header ? PAGE_SIZE : 0);
1490
1491 printk(KERN_INFO "%s: Enabling MTD swap on device %lu, size %llu KB, "
1492 "%u spare, %u bad blocks\n",
1493 MTDSWAP_PREFIX, part, swap_size / 1024, spare_cnt, bad_blocks);
1494
1495 d = kzalloc(sizeof(struct mtdswap_dev), GFP_KERNEL);
1496 if (!d)
1497 return;
1498
1499 mbd_dev = kzalloc(sizeof(struct mtd_blktrans_dev), GFP_KERNEL);
1500 if (!mbd_dev) {
1501 kfree(d);
1502 return;
1503 }
1504
1505 d->mbd_dev = mbd_dev;
1506 mbd_dev->priv = d;
1507
1508 mbd_dev->mtd = mtd;
1509 mbd_dev->devnum = mtd->index;
1510 mbd_dev->size = swap_size >> PAGE_SHIFT;
1511 mbd_dev->tr = tr;
1512
1513 if (!(mtd->flags & MTD_WRITEABLE))
1514 mbd_dev->readonly = 1;
1515
1516 if (mtdswap_init(d, eblocks, spare_cnt) < 0)
1517 goto init_failed;
1518
1519 if (add_mtd_blktrans_dev(mbd_dev) < 0)
1520 goto cleanup;
1521
1522 d->dev = disk_to_dev(mbd_dev->disk);
1523
1524 ret = mtdswap_add_debugfs(d);
1525 if (ret < 0)
1526 goto debugfs_failed;
1527
1528 return;
1529
1530 debugfs_failed:
1531 del_mtd_blktrans_dev(mbd_dev);
1532
1533 cleanup:
1534 mtdswap_cleanup(d);
1535
1536 init_failed:
1537 kfree(mbd_dev);
1538 kfree(d);
1539 }
1540
1541 static void mtdswap_remove_dev(struct mtd_blktrans_dev *dev)
1542 {
1543 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1544
1545 debugfs_remove_recursive(d->debugfs_root);
1546 del_mtd_blktrans_dev(dev);
1547 mtdswap_cleanup(d);
1548 kfree(d);
1549 }
1550
1551 static struct mtd_blktrans_ops mtdswap_ops = {
1552 .name = "mtdswap",
1553 .major = 0,
1554 .part_bits = 0,
1555 .blksize = PAGE_SIZE,
1556 .flush = mtdswap_flush,
1557 .readsect = mtdswap_readsect,
1558 .writesect = mtdswap_writesect,
1559 .discard = mtdswap_discard,
1560 .background = mtdswap_background,
1561 .add_mtd = mtdswap_add_mtd,
1562 .remove_dev = mtdswap_remove_dev,
1563 .owner = THIS_MODULE,
1564 };
1565
1566 static int __init mtdswap_modinit(void)
1567 {
1568 return register_mtd_blktrans(&mtdswap_ops);
1569 }
1570
1571 static void __exit mtdswap_modexit(void)
1572 {
1573 deregister_mtd_blktrans(&mtdswap_ops);
1574 }
1575
1576 module_init(mtdswap_modinit);
1577 module_exit(mtdswap_modexit);
1578
1579
1580 MODULE_LICENSE("GPL");
1581 MODULE_AUTHOR("Jarkko Lavinen <jarkko.lavinen@nokia.com>");
1582 MODULE_DESCRIPTION("Block device access to an MTD suitable for using as "
1583 "swap space");
Linux with added FPC-III support