1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Bad block management
4 *
5 * - Heavily based on MD badblocks code from Neil Brown
6 *
7 * Copyright (c) 2015, Intel Corporation.
8 */
9
10 #include <linux/badblocks.h>
11 #include <linux/seqlock.h>
12 #include <linux/device.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/stddef.h>
16 #include <linux/types.h>
17 #include <linux/slab.h>
18
19 /*
20 * The purpose of badblocks set/clear is to manage bad blocks ranges which are
21 * identified by LBA addresses.
22 *
23 * When the caller of badblocks_set() wants to set a range of bad blocks, the
24 * setting range can be acked or unacked. And the setting range may merge,
25 * overwrite, skip the overlapped already set range, depends on who they are
26 * overlapped or adjacent, and the acknowledgment type of the ranges. It can be
27 * more complicated when the setting range covers multiple already set bad block
28 * ranges, with restrictions of maximum length of each bad range and the bad
29 * table space limitation.
30 *
31 * It is difficult and unnecessary to take care of all the possible situations,
32 * for setting a large range of bad blocks, we can handle it by dividing the
33 * large range into smaller ones when encounter overlap, max range length or
34 * bad table full conditions. Every time only a smaller piece of the bad range
35 * is handled with a limited number of conditions how it is interacted with
36 * possible overlapped or adjacent already set bad block ranges. Then the hard
37 * complicated problem can be much simpler to handle in proper way.
38 *
39 * When setting a range of bad blocks to the bad table, the simplified situations
40 * to be considered are, (The already set bad blocks ranges are naming with
41 * prefix E, and the setting bad blocks range is naming with prefix S)
42 *
43 * 1) A setting range is not overlapped or adjacent to any other already set bad
44 * block range.
45 * +--------+
46 * | S |
47 * +--------+
48 * +-------------+ +-------------+
49 * | E1 | | E2 |
50 * +-------------+ +-------------+
51 * For this situation if the bad blocks table is not full, just allocate a
52 * free slot from the bad blocks table to mark the setting range S. The
53 * result is,
54 * +-------------+ +--------+ +-------------+
55 * | E1 | | S | | E2 |
56 * +-------------+ +--------+ +-------------+
57 * 2) A setting range starts exactly at a start LBA of an already set bad blocks
58 * range.
59 * 2.1) The setting range size < already set range size
60 * +--------+
61 * | S |
62 * +--------+
63 * +-------------+
64 * | E |
65 * +-------------+
66 * 2.1.1) If S and E are both acked or unacked range, the setting range S can
67 * be merged into existing bad range E. The result is,
68 * +-------------+
69 * | S |
70 * +-------------+
71 * 2.1.2) If S is unacked setting and E is acked, the setting will be denied, and
72 * the result is,
73 * +-------------+
74 * | E |
75 * +-------------+
76 * 2.1.3) If S is acked setting and E is unacked, range S can overwrite on E.
77 * An extra slot from the bad blocks table will be allocated for S, and head
78 * of E will move to end of the inserted range S. The result is,
79 * +--------+----+
80 * | S | E |
81 * +--------+----+
82 * 2.2) The setting range size == already set range size
83 * 2.2.1) If S and E are both acked or unacked range, the setting range S can
84 * be merged into existing bad range E. The result is,
85 * +-------------+
86 * | S |
87 * +-------------+
88 * 2.2.2) If S is unacked setting and E is acked, the setting will be denied, and
89 * the result is,
90 * +-------------+
91 * | E |
92 * +-------------+
93 * 2.2.3) If S is acked setting and E is unacked, range S can overwrite all of
94 bad blocks range E. The result is,
95 * +-------------+
96 * | S |
97 * +-------------+
98 * 2.3) The setting range size > already set range size
99 * +-------------------+
100 * | S |
101 * +-------------------+
102 * +-------------+
103 * | E |
104 * +-------------+
105 * For such situation, the setting range S can be treated as two parts, the
106 * first part (S1) is as same size as the already set range E, the second
107 * part (S2) is the rest of setting range.
108 * +-------------+-----+ +-------------+ +-----+
109 * | S1 | S2 | | S1 | | S2 |
110 * +-------------+-----+ ===> +-------------+ +-----+
111 * +-------------+ +-------------+
112 * | E | | E |
113 * +-------------+ +-------------+
114 * Now we only focus on how to handle the setting range S1 and already set
115 * range E, which are already explained in 2.2), for the rest S2 it will be
116 * handled later in next loop.
117 * 3) A setting range starts before the start LBA of an already set bad blocks
118 * range.
119 * +-------------+
120 * | S |
121 * +-------------+
122 * +-------------+
123 * | E |
124 * +-------------+
125 * For this situation, the setting range S can be divided into two parts, the
126 * first (S1) ends at the start LBA of already set range E, the second part
127 * (S2) starts exactly at a start LBA of the already set range E.
128 * +----+---------+ +----+ +---------+
129 * | S1 | S2 | | S1 | | S2 |
130 * +----+---------+ ===> +----+ +---------+
131 * +-------------+ +-------------+
132 * | E | | E |
133 * +-------------+ +-------------+
134 * Now only the first part S1 should be handled in this loop, which is in
135 * similar condition as 1). The rest part S2 has exact same start LBA address
136 * of the already set range E, they will be handled in next loop in one of
137 * situations in 2).
138 * 4) A setting range starts after the start LBA of an already set bad blocks
139 * range.
140 * 4.1) If the setting range S exactly matches the tail part of already set bad
141 * blocks range E, like the following chart shows,
142 * +---------+
143 * | S |
144 * +---------+
145 * +-------------+
146 * | E |
147 * +-------------+
148 * 4.1.1) If range S and E have same acknowledge value (both acked or unacked),
149 * they will be merged into one, the result is,
150 * +-------------+
151 * | S |
152 * +-------------+
153 * 4.1.2) If range E is acked and the setting range S is unacked, the setting
154 * request of S will be rejected, the result is,
155 * +-------------+
156 * | E |
157 * +-------------+
158 * 4.1.3) If range E is unacked, and the setting range S is acked, then S may
159 * overwrite the overlapped range of E, the result is,
160 * +---+---------+
161 * | E | S |
162 * +---+---------+
163 * 4.2) If the setting range S stays in middle of an already set range E, like
164 * the following chart shows,
165 * +----+
166 * | S |
167 * +----+
168 * +--------------+
169 * | E |
170 * +--------------+
171 * 4.2.1) If range S and E have same acknowledge value (both acked or unacked),
172 * they will be merged into one, the result is,
173 * +--------------+
174 * | S |
175 * +--------------+
176 * 4.2.2) If range E is acked and the setting range S is unacked, the setting
177 * request of S will be rejected, the result is also,
178 * +--------------+
179 * | E |
180 * +--------------+
181 * 4.2.3) If range E is unacked, and the setting range S is acked, then S will
182 * inserted into middle of E and split previous range E into two parts (E1
183 * and E2), the result is,
184 * +----+----+----+
185 * | E1 | S | E2 |
186 * +----+----+----+
187 * 4.3) If the setting bad blocks range S is overlapped with an already set bad
188 * blocks range E. The range S starts after the start LBA of range E, and
189 * ends after the end LBA of range E, as the following chart shows,
190 * +-------------------+
191 * | S |
192 * +-------------------+
193 * +-------------+
194 * | E |
195 * +-------------+
196 * For this situation the range S can be divided into two parts, the first
197 * part (S1) ends at end range E, and the second part (S2) has rest range of
198 * origin S.
199 * +---------+---------+ +---------+ +---------+
200 * | S1 | S2 | | S1 | | S2 |
201 * +---------+---------+ ===> +---------+ +---------+
202 * +-------------+ +-------------+
203 * | E | | E |
204 * +-------------+ +-------------+
205 * Now in this loop the setting range S1 and already set range E can be
206 * handled as the situations 4.1), the rest range S2 will be handled in next
207 * loop and ignored in this loop.
208 * 5) A setting bad blocks range S is adjacent to one or more already set bad
209 * blocks range(s), and they are all acked or unacked range.
210 * 5.1) Front merge: If the already set bad blocks range E is before setting
211 * range S and they are adjacent,
212 * +------+
213 * | S |
214 * +------+
215 * +-------+
216 * | E |
217 * +-------+
218 * 5.1.1) When total size of range S and E <= BB_MAX_LEN, and their acknowledge
219 * values are same, the setting range S can front merges into range E. The
220 * result is,
221 * +--------------+
222 * | S |
223 * +--------------+
224 * 5.1.2) Otherwise these two ranges cannot merge, just insert the setting
225 * range S right after already set range E into the bad blocks table. The
226 * result is,
227 * +--------+------+
228 * | E | S |
229 * +--------+------+
230 * 6) Special cases which above conditions cannot handle
231 * 6.1) Multiple already set ranges may merge into less ones in a full bad table
232 * +-------------------------------------------------------+
233 * | S |
234 * +-------------------------------------------------------+
235 * |<----- BB_MAX_LEN ----->|
236 * +-----+ +-----+ +-----+
237 * | E1 | | E2 | | E3 |
238 * +-----+ +-----+ +-----+
239 * In the above example, when the bad blocks table is full, inserting the
240 * first part of setting range S will fail because no more available slot
241 * can be allocated from bad blocks table. In this situation a proper
242 * setting method should be go though all the setting bad blocks range and
243 * look for chance to merge already set ranges into less ones. When there
244 * is available slot from bad blocks table, re-try again to handle more
245 * setting bad blocks ranges as many as possible.
246 * +------------------------+
247 * | S3 |
248 * +------------------------+
249 * |<----- BB_MAX_LEN ----->|
250 * +-----+-----+-----+---+-----+--+
251 * | S1 | S2 |
252 * +-----+-----+-----+---+-----+--+
253 * The above chart shows although the first part (S3) cannot be inserted due
254 * to no-space in bad blocks table, but the following E1, E2 and E3 ranges
255 * can be merged with rest part of S into less range S1 and S2. Now there is
256 * 1 free slot in bad blocks table.
257 * +------------------------+-----+-----+-----+---+-----+--+
258 * | S3 | S1 | S2 |
259 * +------------------------+-----+-----+-----+---+-----+--+
260 * Since the bad blocks table is not full anymore, re-try again for the
261 * origin setting range S. Now the setting range S3 can be inserted into the
262 * bad blocks table with previous freed slot from multiple ranges merge.
263 * 6.2) Front merge after overwrite
264 * In the following example, in bad blocks table, E1 is an acked bad blocks
265 * range and E2 is an unacked bad blocks range, therefore they are not able
266 * to merge into a larger range. The setting bad blocks range S is acked,
267 * therefore part of E2 can be overwritten by S.
268 * +--------+
269 * | S | acknowledged
270 * +--------+ S: 1
271 * +-------+-------------+ E1: 1
272 * | E1 | E2 | E2: 0
273 * +-------+-------------+
274 * With previous simplified routines, after overwriting part of E2 with S,
275 * the bad blocks table should be (E3 is remaining part of E2 which is not
276 * overwritten by S),
277 * acknowledged
278 * +-------+--------+----+ S: 1
279 * | E1 | S | E3 | E1: 1
280 * +-------+--------+----+ E3: 0
281 * The above result is correct but not perfect. Range E1 and S in the bad
282 * blocks table are all acked, merging them into a larger one range may
283 * occupy less bad blocks table space and make badblocks_check() faster.
284 * Therefore in such situation, after overwriting range S, the previous range
285 * E1 should be checked for possible front combination. Then the ideal
286 * result can be,
287 * +----------------+----+ acknowledged
288 * | E1 | E3 | E1: 1
289 * +----------------+----+ E3: 0
290 * 6.3) Behind merge: If the already set bad blocks range E is behind the setting
291 * range S and they are adjacent. Normally we don't need to care about this
292 * because front merge handles this while going though range S from head to
293 * tail, except for the tail part of range S. When the setting range S are
294 * fully handled, all the above simplified routine doesn't check whether the
295 * tail LBA of range S is adjacent to the next already set range and not
296 * merge them even it is possible.
297 * +------+
298 * | S |
299 * +------+
300 * +-------+
301 * | E |
302 * +-------+
303 * For the above special situation, when the setting range S are all handled
304 * and the loop ends, an extra check is necessary for whether next already
305 * set range E is right after S and mergeable.
306 * 6.3.1) When total size of range E and S <= BB_MAX_LEN, and their acknowledge
307 * values are same, the setting range S can behind merges into range E. The
308 * result is,
309 * +--------------+
310 * | S |
311 * +--------------+
312 * 6.3.2) Otherwise these two ranges cannot merge, just insert the setting range
313 * S in front of the already set range E in the bad blocks table. The result
314 * is,
315 * +------+-------+
316 * | S | E |
317 * +------+-------+
318 *
319 * All the above 5 simplified situations and 3 special cases may cover 99%+ of
320 * the bad block range setting conditions. Maybe there is some rare corner case
321 * is not considered and optimized, it won't hurt if badblocks_set() fails due
322 * to no space, or some ranges are not merged to save bad blocks table space.
323 *
324 * Inside badblocks_set() each loop starts by jumping to re_insert label, every
325 * time for the new loop prev_badblocks() is called to find an already set range
326 * which starts before or at current setting range. Since the setting bad blocks
327 * range is handled from head to tail, most of the cases it is unnecessary to do
328 * the binary search inside prev_badblocks(), it is possible to provide a hint
329 * to prev_badblocks() for a fast path, then the expensive binary search can be
330 * avoided. In my test with the hint to prev_badblocks(), except for the first
331 * loop, all rested calls to prev_badblocks() can go into the fast path and
332 * return correct bad blocks table index immediately.
333 *
334 *
335 * Clearing a bad blocks range from the bad block table has similar idea as
336 * setting does, but much more simpler. The only thing needs to be noticed is
337 * when the clearing range hits middle of a bad block range, the existing bad
338 * block range will split into two, and one more item should be added into the
339 * bad block table. The simplified situations to be considered are, (The already
340 * set bad blocks ranges in bad block table are naming with prefix E, and the
341 * clearing bad blocks range is naming with prefix C)
342 *
343 * 1) A clearing range is not overlapped to any already set ranges in bad block
344 * table.
345 * +-----+ | +-----+ | +-----+
346 * | C | | | C | | | C |
347 * +-----+ or +-----+ or +-----+
348 * +---+ | +----+ +----+ | +---+
349 * | E | | | E1 | | E2 | | | E |
350 * +---+ | +----+ +----+ | +---+
351 * For the above situations, no bad block to be cleared and no failure
352 * happens, simply returns 0.
353 * 2) The clearing range hits middle of an already setting bad blocks range in
354 * the bad block table.
355 * +---+
356 * | C |
357 * +---+
358 * +-----------------+
359 * | E |
360 * +-----------------+
361 * In this situation if the bad block table is not full, the range E will be
362 * split into two ranges E1 and E2. The result is,
363 * +------+ +------+
364 * | E1 | | E2 |
365 * +------+ +------+
366 * 3) The clearing range starts exactly at same LBA as an already set bad block range
367 * from the bad block table.
368 * 3.1) Partially covered at head part
369 * +------------+
370 * | C |
371 * +------------+
372 * +-----------------+
373 * | E |
374 * +-----------------+
375 * For this situation, the overlapped already set range will update the
376 * start LBA to end of C and shrink the range to BB_LEN(E) - BB_LEN(C). No
377 * item deleted from bad block table. The result is,
378 * +----+
379 * | E1 |
380 * +----+
381 * 3.2) Exact fully covered
382 * +-----------------+
383 * | C |
384 * +-----------------+
385 * +-----------------+
386 * | E |
387 * +-----------------+
388 * For this situation the whole bad blocks range E will be cleared and its
389 * corresponded item is deleted from the bad block table.
390 * 4) The clearing range exactly ends at same LBA as an already set bad block
391 * range.
392 * +-------+
393 * | C |
394 * +-------+
395 * +-----------------+
396 * | E |
397 * +-----------------+
398 * For the above situation, the already set range E is updated to shrink its
399 * end to the start of C, and reduce its length to BB_LEN(E) - BB_LEN(C).
400 * The result is,
401 * +---------+
402 * | E |
403 * +---------+
404 * 5) The clearing range is partially overlapped with an already set bad block
405 * range from the bad block table.
406 * 5.1) The already set bad block range is front overlapped with the clearing
407 * range.
408 * +----------+
409 * | C |
410 * +----------+
411 * +------------+
412 * | E |
413 * +------------+
414 * For such situation, the clearing range C can be treated as two parts. The
415 * first part ends at the start LBA of range E, and the second part starts at
416 * same LBA of range E.
417 * +----+-----+ +----+ +-----+
418 * | C1 | C2 | | C1 | | C2 |
419 * +----+-----+ ===> +----+ +-----+
420 * +------------+ +------------+
421 * | E | | E |
422 * +------------+ +------------+
423 * Now the first part C1 can be handled as condition 1), and the second part C2 can be
424 * handled as condition 3.1) in next loop.
425 * 5.2) The already set bad block range is behind overlaopped with the clearing
426 * range.
427 * +----------+
428 * | C |
429 * +----------+
430 * +------------+
431 * | E |
432 * +------------+
433 * For such situation, the clearing range C can be treated as two parts. The
434 * first part C1 ends at same end LBA of range E, and the second part starts
435 * at end LBA of range E.
436 * +----+-----+ +----+ +-----+
437 * | C1 | C2 | | C1 | | C2 |
438 * +----+-----+ ===> +----+ +-----+
439 * +------------+ +------------+
440 * | E | | E |
441 * +------------+ +------------+
442 * Now the first part clearing range C1 can be handled as condition 4), and
443 * the second part clearing range C2 can be handled as condition 1) in next
444 * loop.
445 *
446 * All bad blocks range clearing can be simplified into the above 5 situations
447 * by only handling the head part of the clearing range in each run of the
448 * while-loop. The idea is similar to bad blocks range setting but much
449 * simpler.
450 */
451
452 /*
453 * Find the range starts at-or-before 's' from bad table. The search
454 * starts from index 'hint' and stops at index 'hint_end' from the bad
455 * table.
456 */
457 static int prev_by_hint(struct badblocks *bb, sector_t s, int hint)
458 {
459 int hint_end = hint + 2;
460 u64 *p = bb->page;
461 int ret = -1;
462
463 while ((hint < hint_end) && ((hint + 1) <= bb->count) &&
464 (BB_OFFSET(p[hint]) <= s)) {
465 if ((hint + 1) == bb->count || BB_OFFSET(p[hint + 1]) > s) {
466 ret = hint;
467 break;
468 }
469 hint++;
470 }
471
472 return ret;
473 }
474
475 /*
476 * Find the range starts at-or-before bad->start. If 'hint' is provided
477 * (hint >= 0) then search in the bad table from hint firstly. It is
478 * very probably the wanted bad range can be found from the hint index,
479 * then the unnecessary while-loop iteration can be avoided.
480 */
481 static int prev_badblocks(struct badblocks *bb, struct badblocks_context *bad,
482 int hint)
483 {
484 sector_t s = bad->start;
485 int ret = -1;
486 int lo, hi;
487 u64 *p;
488
489 if (!bb->count)
490 goto out;
491
492 if (hint >= 0) {
493 ret = prev_by_hint(bb, s, hint);
494 if (ret >= 0)
495 goto out;
496 }
497
498 lo = 0;
499 hi = bb->count;
500 p = bb->page;
501
502 /* The following bisect search might be unnecessary */
503 if (BB_OFFSET(p[lo]) > s)
504 return -1;
505 if (BB_OFFSET(p[hi - 1]) <= s)
506 return hi - 1;
507
508 /* Do bisect search in bad table */
509 while (hi - lo > 1) {
510 int mid = (lo + hi)/2;
511 sector_t a = BB_OFFSET(p[mid]);
512
513 if (a == s) {
514 ret = mid;
515 goto out;
516 }
517
518 if (a < s)
519 lo = mid;
520 else
521 hi = mid;
522 }
523
524 if (BB_OFFSET(p[lo]) <= s)
525 ret = lo;
526 out:
527 return ret;
528 }
529
530 /*
531 * Return 'true' if the range indicated by 'bad' can be backward merged
532 * with the bad range (from the bad table) index by 'behind'.
533 */
534 static bool can_merge_behind(struct badblocks *bb,
535 struct badblocks_context *bad, int behind)
536 {
537 sector_t sectors = bad->len;
538 sector_t s = bad->start;
539 u64 *p = bb->page;
540
541 if ((s < BB_OFFSET(p[behind])) &&
542 ((s + sectors) >= BB_OFFSET(p[behind])) &&
543 ((BB_END(p[behind]) - s) <= BB_MAX_LEN) &&
544 BB_ACK(p[behind]) == bad->ack)
545 return true;
546 return false;
547 }
548
549 /*
550 * Do backward merge for range indicated by 'bad' and the bad range
551 * (from the bad table) indexed by 'behind'. The return value is merged
552 * sectors from bad->len.
553 */
554 static int behind_merge(struct badblocks *bb, struct badblocks_context *bad,
555 int behind)
556 {
557 sector_t sectors = bad->len;
558 sector_t s = bad->start;
559 u64 *p = bb->page;
560 int merged = 0;
561
562 WARN_ON(s >= BB_OFFSET(p[behind]));
563 WARN_ON((s + sectors) < BB_OFFSET(p[behind]));
564
565 if (s < BB_OFFSET(p[behind])) {
566 merged = BB_OFFSET(p[behind]) - s;
567 p[behind] = BB_MAKE(s, BB_LEN(p[behind]) + merged, bad->ack);
568
569 WARN_ON((BB_LEN(p[behind]) + merged) >= BB_MAX_LEN);
570 }
571
572 return merged;
573 }
574
575 /*
576 * Return 'true' if the range indicated by 'bad' can be forward
577 * merged with the bad range (from the bad table) indexed by 'prev'.
578 */
579 static bool can_merge_front(struct badblocks *bb, int prev,
580 struct badblocks_context *bad)
581 {
582 sector_t s = bad->start;
583 u64 *p = bb->page;
584
585 if (BB_ACK(p[prev]) == bad->ack &&
586 (s < BB_END(p[prev]) ||
587 (s == BB_END(p[prev]) && (BB_LEN(p[prev]) < BB_MAX_LEN))))
588 return true;
589 return false;
590 }
591
592 /*
593 * Do forward merge for range indicated by 'bad' and the bad range
594 * (from bad table) indexed by 'prev'. The return value is sectors
595 * merged from bad->len.
596 */
597 static int front_merge(struct badblocks *bb, int prev, struct badblocks_context *bad)
598 {
599 sector_t sectors = bad->len;
600 sector_t s = bad->start;
601 u64 *p = bb->page;
602 int merged = 0;
603
604 WARN_ON(s > BB_END(p[prev]));
605
606 if (s < BB_END(p[prev])) {
607 merged = min_t(sector_t, sectors, BB_END(p[prev]) - s);
608 } else {
609 merged = min_t(sector_t, sectors, BB_MAX_LEN - BB_LEN(p[prev]));
610 if ((prev + 1) < bb->count &&
611 merged > (BB_OFFSET(p[prev + 1]) - BB_END(p[prev]))) {
612 merged = BB_OFFSET(p[prev + 1]) - BB_END(p[prev]);
613 }
614
615 p[prev] = BB_MAKE(BB_OFFSET(p[prev]),
616 BB_LEN(p[prev]) + merged, bad->ack);
617 }
618
619 return merged;
620 }
621
622 /*
623 * 'Combine' is a special case which can_merge_front() is not able to
624 * handle: If a bad range (indexed by 'prev' from bad table) exactly
625 * starts as bad->start, and the bad range ahead of 'prev' (indexed by
626 * 'prev - 1' from bad table) exactly ends at where 'prev' starts, and
627 * the sum of their lengths does not exceed BB_MAX_LEN limitation, then
628 * these two bad range (from bad table) can be combined.
629 *
630 * Return 'true' if bad ranges indexed by 'prev' and 'prev - 1' from bad
631 * table can be combined.
632 */
633 static bool can_combine_front(struct badblocks *bb, int prev,
634 struct badblocks_context *bad)
635 {
636 u64 *p = bb->page;
637
638 if ((prev > 0) &&
639 (BB_OFFSET(p[prev]) == bad->start) &&
640 (BB_END(p[prev - 1]) == BB_OFFSET(p[prev])) &&
641 (BB_LEN(p[prev - 1]) + BB_LEN(p[prev]) <= BB_MAX_LEN) &&
642 (BB_ACK(p[prev - 1]) == BB_ACK(p[prev])))
643 return true;
644 return false;
645 }
646
647 /*
648 * Combine the bad ranges indexed by 'prev' and 'prev - 1' (from bad
649 * table) into one larger bad range, and the new range is indexed by
650 * 'prev - 1'.
651 * The caller of front_combine() will decrease bb->count, therefore
652 * it is unnecessary to clear p[perv] after front merge.
653 */
654 static void front_combine(struct badblocks *bb, int prev)
655 {
656 u64 *p = bb->page;
657
658 p[prev - 1] = BB_MAKE(BB_OFFSET(p[prev - 1]),
659 BB_LEN(p[prev - 1]) + BB_LEN(p[prev]),
660 BB_ACK(p[prev]));
661 if ((prev + 1) < bb->count)
662 memmove(p + prev, p + prev + 1, (bb->count - prev - 1) * 8);
663 }
664
665 /*
666 * Return 'true' if the range indicated by 'bad' is exactly forward
667 * overlapped with the bad range (from bad table) indexed by 'front'.
668 * Exactly forward overlap means the bad range (from bad table) indexed
669 * by 'prev' does not cover the whole range indicated by 'bad'.
670 */
671 static bool overlap_front(struct badblocks *bb, int front,
672 struct badblocks_context *bad)
673 {
674 u64 *p = bb->page;
675
676 if (bad->start >= BB_OFFSET(p[front]) &&
677 bad->start < BB_END(p[front]))
678 return true;
679 return false;
680 }
681
682 /*
683 * Return 'true' if the range indicated by 'bad' is exactly backward
684 * overlapped with the bad range (from bad table) indexed by 'behind'.
685 */
686 static bool overlap_behind(struct badblocks *bb, struct badblocks_context *bad,
687 int behind)
688 {
689 u64 *p = bb->page;
690
691 if (bad->start < BB_OFFSET(p[behind]) &&
692 (bad->start + bad->len) > BB_OFFSET(p[behind]))
693 return true;
694 return false;
695 }
696
697 /*
698 * Return 'true' if the range indicated by 'bad' can overwrite the bad
699 * range (from bad table) indexed by 'prev'.
700 *
701 * The range indicated by 'bad' can overwrite the bad range indexed by
702 * 'prev' when,
703 * 1) The whole range indicated by 'bad' can cover partial or whole bad
704 * range (from bad table) indexed by 'prev'.
705 * 2) The ack value of 'bad' is larger or equal to the ack value of bad
706 * range 'prev'.
707 *
708 * If the overwriting doesn't cover the whole bad range (from bad table)
709 * indexed by 'prev', new range might be split from existing bad range,
710 * 1) The overwrite covers head or tail part of existing bad range, 1
711 * extra bad range will be split and added into the bad table.
712 * 2) The overwrite covers middle of existing bad range, 2 extra bad
713 * ranges will be split (ahead and after the overwritten range) and
714 * added into the bad table.
715 * The number of extra split ranges of the overwriting is stored in
716 * 'extra' and returned for the caller.
717 */
718 static bool can_front_overwrite(struct badblocks *bb, int prev,
719 struct badblocks_context *bad, int *extra)
720 {
721 u64 *p = bb->page;
722 int len;
723
724 WARN_ON(!overlap_front(bb, prev, bad));
725
726 if (BB_ACK(p[prev]) >= bad->ack)
727 return false;
728
729 if (BB_END(p[prev]) <= (bad->start + bad->len)) {
730 len = BB_END(p[prev]) - bad->start;
731 if (BB_OFFSET(p[prev]) == bad->start)
732 *extra = 0;
733 else
734 *extra = 1;
735
736 bad->len = len;
737 } else {
738 if (BB_OFFSET(p[prev]) == bad->start)
739 *extra = 1;
740 else
741 /*
742 * prev range will be split into two, beside the overwritten
743 * one, an extra slot needed from bad table.
744 */
745 *extra = 2;
746 }
747
748 if ((bb->count + (*extra)) >= MAX_BADBLOCKS)
749 return false;
750
751 return true;
752 }
753
754 /*
755 * Do the overwrite from the range indicated by 'bad' to the bad range
756 * (from bad table) indexed by 'prev'.
757 * The previously called can_front_overwrite() will provide how many
758 * extra bad range(s) might be split and added into the bad table. All
759 * the splitting cases in the bad table will be handled here.
760 */
761 static int front_overwrite(struct badblocks *bb, int prev,
762 struct badblocks_context *bad, int extra)
763 {
764 u64 *p = bb->page;
765 sector_t orig_end = BB_END(p[prev]);
766 int orig_ack = BB_ACK(p[prev]);
767
768 switch (extra) {
769 case 0:
770 p[prev] = BB_MAKE(BB_OFFSET(p[prev]), BB_LEN(p[prev]),
771 bad->ack);
772 break;
773 case 1:
774 if (BB_OFFSET(p[prev]) == bad->start) {
775 p[prev] = BB_MAKE(BB_OFFSET(p[prev]),
776 bad->len, bad->ack);
777 memmove(p + prev + 2, p + prev + 1,
778 (bb->count - prev - 1) * 8);
779 p[prev + 1] = BB_MAKE(bad->start + bad->len,
780 orig_end - BB_END(p[prev]),
781 orig_ack);
782 } else {
783 p[prev] = BB_MAKE(BB_OFFSET(p[prev]),
784 bad->start - BB_OFFSET(p[prev]),
785 orig_ack);
786 /*
787 * prev +2 -> prev + 1 + 1, which is for,
788 * 1) prev + 1: the slot index of the previous one
789 * 2) + 1: one more slot for extra being 1.
790 */
791 memmove(p + prev + 2, p + prev + 1,
792 (bb->count - prev - 1) * 8);
793 p[prev + 1] = BB_MAKE(bad->start, bad->len, bad->ack);
794 }
795 break;
796 case 2:
797 p[prev] = BB_MAKE(BB_OFFSET(p[prev]),
798 bad->start - BB_OFFSET(p[prev]),
799 orig_ack);
800 /*
801 * prev + 3 -> prev + 1 + 2, which is for,
802 * 1) prev + 1: the slot index of the previous one
803 * 2) + 2: two more slots for extra being 2.
804 */
805 memmove(p + prev + 3, p + prev + 1,
806 (bb->count - prev - 1) * 8);
807 p[prev + 1] = BB_MAKE(bad->start, bad->len, bad->ack);
808 p[prev + 2] = BB_MAKE(BB_END(p[prev + 1]),
809 orig_end - BB_END(p[prev + 1]),
810 orig_ack);
811 break;
812 default:
813 break;
814 }
815
816 return bad->len;
817 }
818
819 /*
820 * Explicitly insert a range indicated by 'bad' to the bad table, where
821 * the location is indexed by 'at'.
822 */
823 static int insert_at(struct badblocks *bb, int at, struct badblocks_context *bad)
824 {
825 u64 *p = bb->page;
826 int len;
827
828 WARN_ON(badblocks_full(bb));
829
830 len = min_t(sector_t, bad->len, BB_MAX_LEN);
831 if (at < bb->count)
832 memmove(p + at + 1, p + at, (bb->count - at) * 8);
833 p[at] = BB_MAKE(bad->start, len, bad->ack);
834
835 return len;
836 }
837
838 static void badblocks_update_acked(struct badblocks *bb)
839 {
840 bool unacked = false;
841 u64 *p = bb->page;
842 int i;
843
844 if (!bb->unacked_exist)
845 return;
846
847 for (i = 0; i < bb->count ; i++) {
848 if (!BB_ACK(p[i])) {
849 unacked = true;
850 break;
851 }
852 }
853
854 if (!unacked)
855 bb->unacked_exist = 0;
856 }
857
858 /* Do exact work to set bad block range into the bad block table */
859 static int _badblocks_set(struct badblocks *bb, sector_t s, int sectors,
860 int acknowledged)
861 {
862 int retried = 0, space_desired = 0;
863 int orig_len, len = 0, added = 0;
864 struct badblocks_context bad;
865 int prev = -1, hint = -1;
866 sector_t orig_start;
867 unsigned long flags;
868 int rv = 0;
869 u64 *p;
870
871 if (bb->shift < 0)
872 /* badblocks are disabled */
873 return 1;
874
875 if (sectors == 0)
876 /* Invalid sectors number */
877 return 1;
878
879 if (bb->shift) {
880 /* round the start down, and the end up */
881 sector_t next = s + sectors;
882
883 rounddown(s, bb->shift);
884 roundup(next, bb->shift);
885 sectors = next - s;
886 }
887
888 write_seqlock_irqsave(&bb->lock, flags);
889
890 orig_start = s;
891 orig_len = sectors;
892 bad.ack = acknowledged;
893 p = bb->page;
894
895 re_insert:
896 bad.start = s;
897 bad.len = sectors;
898 len = 0;
899
900 if (badblocks_empty(bb)) {
901 len = insert_at(bb, 0, &bad);
902 bb->count++;
903 added++;
904 goto update_sectors;
905 }
906
907 prev = prev_badblocks(bb, &bad, hint);
908
909 /* start before all badblocks */
910 if (prev < 0) {
911 if (!badblocks_full(bb)) {
912 /* insert on the first */
913 if (bad.len > (BB_OFFSET(p[0]) - bad.start))
914 bad.len = BB_OFFSET(p[0]) - bad.start;
915 len = insert_at(bb, 0, &bad);
916 bb->count++;
917 added++;
918 hint = 0;
919 goto update_sectors;
920 }
921
922 /* No sapce, try to merge */
923 if (overlap_behind(bb, &bad, 0)) {
924 if (can_merge_behind(bb, &bad, 0)) {
925 len = behind_merge(bb, &bad, 0);
926 added++;
927 } else {
928 len = BB_OFFSET(p[0]) - s;
929 space_desired = 1;
930 }
931 hint = 0;
932 goto update_sectors;
933 }
934
935 /* no table space and give up */
936 goto out;
937 }
938
939 /* in case p[prev-1] can be merged with p[prev] */
940 if (can_combine_front(bb, prev, &bad)) {
941 front_combine(bb, prev);
942 bb->count--;
943 added++;
944 hint = prev;
945 goto update_sectors;
946 }
947
948 if (overlap_front(bb, prev, &bad)) {
949 if (can_merge_front(bb, prev, &bad)) {
950 len = front_merge(bb, prev, &bad);
951 added++;
952 } else {
953 int extra = 0;
954
955 if (!can_front_overwrite(bb, prev, &bad, &extra)) {
956 len = min_t(sector_t,
957 BB_END(p[prev]) - s, sectors);
958 hint = prev;
959 goto update_sectors;
960 }
961
962 len = front_overwrite(bb, prev, &bad, extra);
963 added++;
964 bb->count += extra;
965
966 if (can_combine_front(bb, prev, &bad)) {
967 front_combine(bb, prev);
968 bb->count--;
969 }
970 }
971 hint = prev;
972 goto update_sectors;
973 }
974
975 if (can_merge_front(bb, prev, &bad)) {
976 len = front_merge(bb, prev, &bad);
977 added++;
978 hint = prev;
979 goto update_sectors;
980 }
981
982 /* if no space in table, still try to merge in the covered range */
983 if (badblocks_full(bb)) {
984 /* skip the cannot-merge range */
985 if (((prev + 1) < bb->count) &&
986 overlap_behind(bb, &bad, prev + 1) &&
987 ((s + sectors) >= BB_END(p[prev + 1]))) {
988 len = BB_END(p[prev + 1]) - s;
989 hint = prev + 1;
990 goto update_sectors;
991 }
992
993 /* no retry any more */
994 len = sectors;
995 space_desired = 1;
996 hint = -1;
997 goto update_sectors;
998 }
999
1000 /* cannot merge and there is space in bad table */
1001 if ((prev + 1) < bb->count &&
1002 overlap_behind(bb, &bad, prev + 1))
1003 bad.len = min_t(sector_t,
1004 bad.len, BB_OFFSET(p[prev + 1]) - bad.start);
1005
1006 len = insert_at(bb, prev + 1, &bad);
1007 bb->count++;
1008 added++;
1009 hint = prev + 1;
1010
1011 update_sectors:
1012 s += len;
1013 sectors -= len;
1014
1015 if (sectors > 0)
1016 goto re_insert;
1017
1018 WARN_ON(sectors < 0);
1019
1020 /*
1021 * Check whether the following already set range can be
1022 * merged. (prev < 0) condition is not handled here,
1023 * because it's already complicated enough.
1024 */
1025 if (prev >= 0 &&
1026 (prev + 1) < bb->count &&
1027 BB_END(p[prev]) == BB_OFFSET(p[prev + 1]) &&
1028 (BB_LEN(p[prev]) + BB_LEN(p[prev + 1])) <= BB_MAX_LEN &&
1029 BB_ACK(p[prev]) == BB_ACK(p[prev + 1])) {
1030 p[prev] = BB_MAKE(BB_OFFSET(p[prev]),
1031 BB_LEN(p[prev]) + BB_LEN(p[prev + 1]),
1032 BB_ACK(p[prev]));
1033
1034 if ((prev + 2) < bb->count)
1035 memmove(p + prev + 1, p + prev + 2,
1036 (bb->count - (prev + 2)) * 8);
1037 bb->count--;
1038 }
1039
1040 if (space_desired && !badblocks_full(bb)) {
1041 s = orig_start;
1042 sectors = orig_len;
1043 space_desired = 0;
1044 if (retried++ < 3)
1045 goto re_insert;
1046 }
1047
1048 out:
1049 if (added) {
1050 set_changed(bb);
1051
1052 if (!acknowledged)
1053 bb->unacked_exist = 1;
1054 else
1055 badblocks_update_acked(bb);
1056 }
1057
1058 write_sequnlock_irqrestore(&bb->lock, flags);
1059
1060 if (!added)
1061 rv = 1;
1062
1063 return rv;
1064 }
1065
1066 /*
1067 * Clear the bad block range from bad block table which is front overlapped
1068 * with the clearing range. The return value is how many sectors from an
1069 * already set bad block range are cleared. If the whole bad block range is
1070 * covered by the clearing range and fully cleared, 'delete' is set as 1 for
1071 * the caller to reduce bb->count.
1072 */
1073 static int front_clear(struct badblocks *bb, int prev,
1074 struct badblocks_context *bad, int *deleted)
1075 {
1076 sector_t sectors = bad->len;
1077 sector_t s = bad->start;
1078 u64 *p = bb->page;
1079 int cleared = 0;
1080
1081 *deleted = 0;
1082 if (s == BB_OFFSET(p[prev])) {
1083 if (BB_LEN(p[prev]) > sectors) {
1084 p[prev] = BB_MAKE(BB_OFFSET(p[prev]) + sectors,
1085 BB_LEN(p[prev]) - sectors,
1086 BB_ACK(p[prev]));
1087 cleared = sectors;
1088 } else {
1089 /* BB_LEN(p[prev]) <= sectors */
1090 cleared = BB_LEN(p[prev]);
1091 if ((prev + 1) < bb->count)
1092 memmove(p + prev, p + prev + 1,
1093 (bb->count - prev - 1) * 8);
1094 *deleted = 1;
1095 }
1096 } else if (s > BB_OFFSET(p[prev])) {
1097 if (BB_END(p[prev]) <= (s + sectors)) {
1098 cleared = BB_END(p[prev]) - s;
1099 p[prev] = BB_MAKE(BB_OFFSET(p[prev]),
1100 s - BB_OFFSET(p[prev]),
1101 BB_ACK(p[prev]));
1102 } else {
1103 /* Splitting is handled in front_splitting_clear() */
1104 BUG();
1105 }
1106 }
1107
1108 return cleared;
1109 }
1110
1111 /*
1112 * Handle the condition that the clearing range hits middle of an already set
1113 * bad block range from bad block table. In this condition the existing bad
1114 * block range is split into two after the middle part is cleared.
1115 */
1116 static int front_splitting_clear(struct badblocks *bb, int prev,
1117 struct badblocks_context *bad)
1118 {
1119 u64 *p = bb->page;
1120 u64 end = BB_END(p[prev]);
1121 int ack = BB_ACK(p[prev]);
1122 sector_t sectors = bad->len;
1123 sector_t s = bad->start;
1124
1125 p[prev] = BB_MAKE(BB_OFFSET(p[prev]),
1126 s - BB_OFFSET(p[prev]),
1127 ack);
1128 memmove(p + prev + 2, p + prev + 1, (bb->count - prev - 1) * 8);
1129 p[prev + 1] = BB_MAKE(s + sectors, end - s - sectors, ack);
1130 return sectors;
1131 }
1132
1133 /* Do the exact work to clear bad block range from the bad block table */
1134 static int _badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
1135 {
1136 struct badblocks_context bad;
1137 int prev = -1, hint = -1;
1138 int len = 0, cleared = 0;
1139 int rv = 0;
1140 u64 *p;
1141
1142 if (bb->shift < 0)
1143 /* badblocks are disabled */
1144 return 1;
1145
1146 if (sectors == 0)
1147 /* Invalid sectors number */
1148 return 1;
1149
1150 if (bb->shift) {
1151 sector_t target;
1152
1153 /* When clearing we round the start up and the end down.
1154 * This should not matter as the shift should align with
1155 * the block size and no rounding should ever be needed.
1156 * However it is better the think a block is bad when it
1157 * isn't than to think a block is not bad when it is.
1158 */
1159 target = s + sectors;
1160 roundup(s, bb->shift);
1161 rounddown(target, bb->shift);
1162 sectors = target - s;
1163 }
1164
1165 write_seqlock_irq(&bb->lock);
1166
1167 bad.ack = true;
1168 p = bb->page;
1169
1170 re_clear:
1171 bad.start = s;
1172 bad.len = sectors;
1173
1174 if (badblocks_empty(bb)) {
1175 len = sectors;
1176 cleared++;
1177 goto update_sectors;
1178 }
1179
1180
1181 prev = prev_badblocks(bb, &bad, hint);
1182
1183 /* Start before all badblocks */
1184 if (prev < 0) {
1185 if (overlap_behind(bb, &bad, 0)) {
1186 len = BB_OFFSET(p[0]) - s;
1187 hint = 0;
1188 } else {
1189 len = sectors;
1190 }
1191 /*
1192 * Both situations are to clear non-bad range,
1193 * should be treated as successful
1194 */
1195 cleared++;
1196 goto update_sectors;
1197 }
1198
1199 /* Start after all badblocks */
1200 if ((prev + 1) >= bb->count && !overlap_front(bb, prev, &bad)) {
1201 len = sectors;
1202 cleared++;
1203 goto update_sectors;
1204 }
1205
1206 /* Clear will split a bad record but the table is full */
1207 if (badblocks_full(bb) && (BB_OFFSET(p[prev]) < bad.start) &&
1208 (BB_END(p[prev]) > (bad.start + sectors))) {
1209 len = sectors;
1210 goto update_sectors;
1211 }
1212
1213 if (overlap_front(bb, prev, &bad)) {
1214 if ((BB_OFFSET(p[prev]) < bad.start) &&
1215 (BB_END(p[prev]) > (bad.start + bad.len))) {
1216 /* Splitting */
1217 if ((bb->count + 1) < MAX_BADBLOCKS) {
1218 len = front_splitting_clear(bb, prev, &bad);
1219 bb->count += 1;
1220 cleared++;
1221 } else {
1222 /* No space to split, give up */
1223 len = sectors;
1224 }
1225 } else {
1226 int deleted = 0;
1227
1228 len = front_clear(bb, prev, &bad, &deleted);
1229 bb->count -= deleted;
1230 cleared++;
1231 hint = prev;
1232 }
1233
1234 goto update_sectors;
1235 }
1236
1237 /* Not front overlap, but behind overlap */
1238 if ((prev + 1) < bb->count && overlap_behind(bb, &bad, prev + 1)) {
1239 len = BB_OFFSET(p[prev + 1]) - bad.start;
1240 hint = prev + 1;
1241 /* Clear non-bad range should be treated as successful */
1242 cleared++;
1243 goto update_sectors;
1244 }
1245
1246 /* Not cover any badblocks range in the table */
1247 len = sectors;
1248 /* Clear non-bad range should be treated as successful */
1249 cleared++;
1250
1251 update_sectors:
1252 s += len;
1253 sectors -= len;
1254
1255 if (sectors > 0)
1256 goto re_clear;
1257
1258 WARN_ON(sectors < 0);
1259
1260 if (cleared) {
1261 badblocks_update_acked(bb);
1262 set_changed(bb);
1263 }
1264
1265 write_sequnlock_irq(&bb->lock);
1266
1267 if (!cleared)
1268 rv = 1;
1269
1270 return rv;
1271 }
1272
1273 /* Do the exact work to check bad blocks range from the bad block table */
1274 static int _badblocks_check(struct badblocks *bb, sector_t s, int sectors,
1275 sector_t *first_bad, int *bad_sectors)
1276 {
1277 int unacked_badblocks, acked_badblocks;
1278 int prev = -1, hint = -1, set = 0;
1279 struct badblocks_context bad;
1280 unsigned int seq;
1281 int len, rv;
1282 u64 *p;
1283
1284 WARN_ON(bb->shift < 0 || sectors == 0);
1285
1286 if (bb->shift > 0) {
1287 sector_t target;
1288
1289 /* round the start down, and the end up */
1290 target = s + sectors;
1291 rounddown(s, bb->shift);
1292 roundup(target, bb->shift);
1293 sectors = target - s;
1294 }
1295
1296 retry:
1297 seq = read_seqbegin(&bb->lock);
1298
1299 p = bb->page;
1300 unacked_badblocks = 0;
1301 acked_badblocks = 0;
1302
1303 re_check:
1304 bad.start = s;
1305 bad.len = sectors;
1306
1307 if (badblocks_empty(bb)) {
1308 len = sectors;
1309 goto update_sectors;
1310 }
1311
1312 prev = prev_badblocks(bb, &bad, hint);
1313
1314 /* start after all badblocks */
1315 if ((prev >= 0) &&
1316 ((prev + 1) >= bb->count) && !overlap_front(bb, prev, &bad)) {
1317 len = sectors;
1318 goto update_sectors;
1319 }
1320
1321 /* Overlapped with front badblocks record */
1322 if ((prev >= 0) && overlap_front(bb, prev, &bad)) {
1323 if (BB_ACK(p[prev]))
1324 acked_badblocks++;
1325 else
1326 unacked_badblocks++;
1327
1328 if (BB_END(p[prev]) >= (s + sectors))
1329 len = sectors;
1330 else
1331 len = BB_END(p[prev]) - s;
1332
1333 if (set == 0) {
1334 *first_bad = BB_OFFSET(p[prev]);
1335 *bad_sectors = BB_LEN(p[prev]);
1336 set = 1;
1337 }
1338 goto update_sectors;
1339 }
1340
1341 /* Not front overlap, but behind overlap */
1342 if ((prev + 1) < bb->count && overlap_behind(bb, &bad, prev + 1)) {
1343 len = BB_OFFSET(p[prev + 1]) - bad.start;
1344 hint = prev + 1;
1345 goto update_sectors;
1346 }
1347
1348 /* not cover any badblocks range in the table */
1349 len = sectors;
1350
1351 update_sectors:
1352 s += len;
1353 sectors -= len;
1354
1355 if (sectors > 0)
1356 goto re_check;
1357
1358 WARN_ON(sectors < 0);
1359
1360 if (unacked_badblocks > 0)
1361 rv = -1;
1362 else if (acked_badblocks > 0)
1363 rv = 1;
1364 else
1365 rv = 0;
1366
1367 if (read_seqretry(&bb->lock, seq))
1368 goto retry;
1369
1370 return rv;
1371 }
1372
1373 /**
1374 * badblocks_check() - check a given range for bad sectors
1375 * @bb: the badblocks structure that holds all badblock information
1376 * @s: sector (start) at which to check for badblocks
1377 * @sectors: number of sectors to check for badblocks
1378 * @first_bad: pointer to store location of the first badblock
1379 * @bad_sectors: pointer to store number of badblocks after @first_bad
1380 *
1381 * We can record which blocks on each device are 'bad' and so just
1382 * fail those blocks, or that stripe, rather than the whole device.
1383 * Entries in the bad-block table are 64bits wide. This comprises:
1384 * Length of bad-range, in sectors: 0-511 for lengths 1-512
1385 * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes)
1386 * A 'shift' can be set so that larger blocks are tracked and
1387 * consequently larger devices can be covered.
1388 * 'Acknowledged' flag - 1 bit. - the most significant bit.
1389 *
1390 * Locking of the bad-block table uses a seqlock so badblocks_check
1391 * might need to retry if it is very unlucky.
1392 * We will sometimes want to check for bad blocks in a bi_end_io function,
1393 * so we use the write_seqlock_irq variant.
1394 *
1395 * When looking for a bad block we specify a range and want to
1396 * know if any block in the range is bad. So we binary-search
1397 * to the last range that starts at-or-before the given endpoint,
1398 * (or "before the sector after the target range")
1399 * then see if it ends after the given start.
1400 *
1401 * Return:
1402 * 0: there are no known bad blocks in the range
1403 * 1: there are known bad block which are all acknowledged
1404 * -1: there are bad blocks which have not yet been acknowledged in metadata.
1405 * plus the start/length of the first bad section we overlap.
1406 */
1407 int badblocks_check(struct badblocks *bb, sector_t s, int sectors,
1408 sector_t *first_bad, int *bad_sectors)
1409 {
1410 return _badblocks_check(bb, s, sectors, first_bad, bad_sectors);
1411 }
1412 EXPORT_SYMBOL_GPL(badblocks_check);
1413
1414 /**
1415 * badblocks_set() - Add a range of bad blocks to the table.
1416 * @bb: the badblocks structure that holds all badblock information
1417 * @s: first sector to mark as bad
1418 * @sectors: number of sectors to mark as bad
1419 * @acknowledged: weather to mark the bad sectors as acknowledged
1420 *
1421 * This might extend the table, or might contract it if two adjacent ranges
1422 * can be merged. We binary-search to find the 'insertion' point, then
1423 * decide how best to handle it.
1424 *
1425 * Return:
1426 * 0: success
1427 * 1: failed to set badblocks (out of space)
1428 */
1429 int badblocks_set(struct badblocks *bb, sector_t s, int sectors,
1430 int acknowledged)
1431 {
1432 return _badblocks_set(bb, s, sectors, acknowledged);
1433 }
1434 EXPORT_SYMBOL_GPL(badblocks_set);
1435
1436 /**
1437 * badblocks_clear() - Remove a range of bad blocks to the table.
1438 * @bb: the badblocks structure that holds all badblock information
1439 * @s: first sector to mark as bad
1440 * @sectors: number of sectors to mark as bad
1441 *
1442 * This may involve extending the table if we spilt a region,
1443 * but it must not fail. So if the table becomes full, we just
1444 * drop the remove request.
1445 *
1446 * Return:
1447 * 0: success
1448 * 1: failed to clear badblocks
1449 */
1450 int badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
1451 {
1452 return _badblocks_clear(bb, s, sectors);
1453 }
1454 EXPORT_SYMBOL_GPL(badblocks_clear);
1455
1456 /**
1457 * ack_all_badblocks() - Acknowledge all bad blocks in a list.
1458 * @bb: the badblocks structure that holds all badblock information
1459 *
1460 * This only succeeds if ->changed is clear. It is used by
1461 * in-kernel metadata updates
1462 */
1463 void ack_all_badblocks(struct badblocks *bb)
1464 {
1465 if (bb->page == NULL || bb->changed)
1466 /* no point even trying */
1467 return;
1468 write_seqlock_irq(&bb->lock);
1469
1470 if (bb->changed == 0 && bb->unacked_exist) {
1471 u64 *p = bb->page;
1472 int i;
1473
1474 for (i = 0; i < bb->count ; i++) {
1475 if (!BB_ACK(p[i])) {
1476 sector_t start = BB_OFFSET(p[i]);
1477 int len = BB_LEN(p[i]);
1478
1479 p[i] = BB_MAKE(start, len, 1);
1480 }
1481 }
1482 bb->unacked_exist = 0;
1483 }
1484 write_sequnlock_irq(&bb->lock);
1485 }
1486 EXPORT_SYMBOL_GPL(ack_all_badblocks);
1487
1488 /**
1489 * badblocks_show() - sysfs access to bad-blocks list
1490 * @bb: the badblocks structure that holds all badblock information
1491 * @page: buffer received from sysfs
1492 * @unack: weather to show unacknowledged badblocks
1493 *
1494 * Return:
1495 * Length of returned data
1496 */
1497 ssize_t badblocks_show(struct badblocks *bb, char *page, int unack)
1498 {
1499 size_t len;
1500 int i;
1501 u64 *p = bb->page;
1502 unsigned seq;
1503
1504 if (bb->shift < 0)
1505 return 0;
1506
1507 retry:
1508 seq = read_seqbegin(&bb->lock);
1509
1510 len = 0;
1511 i = 0;
1512
1513 while (len < PAGE_SIZE && i < bb->count) {
1514 sector_t s = BB_OFFSET(p[i]);
1515 unsigned int length = BB_LEN(p[i]);
1516 int ack = BB_ACK(p[i]);
1517
1518 i++;
1519
1520 if (unack && ack)
1521 continue;
1522
1523 len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n",
1524 (unsigned long long)s << bb->shift,
1525 length << bb->shift);
1526 }
1527 if (unack && len == 0)
1528 bb->unacked_exist = 0;
1529
1530 if (read_seqretry(&bb->lock, seq))
1531 goto retry;
1532
1533 return len;
1534 }
1535 EXPORT_SYMBOL_GPL(badblocks_show);
1536
1537 /**
1538 * badblocks_store() - sysfs access to bad-blocks list
1539 * @bb: the badblocks structure that holds all badblock information
1540 * @page: buffer received from sysfs
1541 * @len: length of data received from sysfs
1542 * @unack: weather to show unacknowledged badblocks
1543 *
1544 * Return:
1545 * Length of the buffer processed or -ve error.
1546 */
1547 ssize_t badblocks_store(struct badblocks *bb, const char *page, size_t len,
1548 int unack)
1549 {
1550 unsigned long long sector;
1551 int length;
1552 char newline;
1553
1554 switch (sscanf(page, "%llu %d%c", §or, &length, &newline)) {
1555 case 3:
1556 if (newline != '\n')
1557 return -EINVAL;
1558 fallthrough;
1559 case 2:
1560 if (length <= 0)
1561 return -EINVAL;
1562 break;
1563 default:
1564 return -EINVAL;
1565 }
1566
1567 if (badblocks_set(bb, sector, length, !unack))
1568 return -ENOSPC;
1569 else
1570 return len;
1571 }
1572 EXPORT_SYMBOL_GPL(badblocks_store);
1573
1574 static int __badblocks_init(struct device *dev, struct badblocks *bb,
1575 int enable)
1576 {
1577 bb->dev = dev;
1578 bb->count = 0;
1579 if (enable)
1580 bb->shift = 0;
1581 else
1582 bb->shift = -1;
1583 if (dev)
1584 bb->page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL);
1585 else
1586 bb->page = kzalloc(PAGE_SIZE, GFP_KERNEL);
1587 if (!bb->page) {
1588 bb->shift = -1;
1589 return -ENOMEM;
1590 }
1591 seqlock_init(&bb->lock);
1592
1593 return 0;
1594 }
1595
1596 /**
1597 * badblocks_init() - initialize the badblocks structure
1598 * @bb: the badblocks structure that holds all badblock information
1599 * @enable: weather to enable badblocks accounting
1600 *
1601 * Return:
1602 * 0: success
1603 * -ve errno: on error
1604 */
1605 int badblocks_init(struct badblocks *bb, int enable)
1606 {
1607 return __badblocks_init(NULL, bb, enable);
1608 }
1609 EXPORT_SYMBOL_GPL(badblocks_init);
1610
1611 int devm_init_badblocks(struct device *dev, struct badblocks *bb)
1612 {
1613 if (!bb)
1614 return -EINVAL;
1615 return __badblocks_init(dev, bb, 1);
1616 }
1617 EXPORT_SYMBOL_GPL(devm_init_badblocks);
1618
1619 /**
1620 * badblocks_exit() - free the badblocks structure
1621 * @bb: the badblocks structure that holds all badblock information
1622 */
1623 void badblocks_exit(struct badblocks *bb)
1624 {
1625 if (!bb)
1626 return;
1627 if (bb->dev)
1628 devm_kfree(bb->dev, bb->page);
1629 else
1630 kfree(bb->page);
1631 bb->page = NULL;
1632 }
1633 EXPORT_SYMBOL_GPL(badblocks_exit);
1634
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