1634 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Bad block management4 *5 * - Heavily based on MD badblocks code from Neil Brown6 *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 are21 * identified by LBA addresses.22 *23 * When the caller of badblocks_set() wants to set a range of bad blocks, the24 * 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 are26 * overlapped or adjacent, and the acknowledgment type of the ranges. It can be27 * more complicated when the setting range covers multiple already set bad block28 * ranges, with restrictions of maximum length of each bad range and the bad29 * 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 the33 * large range into smaller ones when encounter overlap, max range length or34 * bad table full conditions. Every time only a smaller piece of the bad range35 * is handled with a limited number of conditions how it is interacted with36 * possible overlapped or adjacent already set bad block ranges. Then the hard37 * 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 situations40 * to be considered are, (The already set bad blocks ranges are naming with41 * 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 bad44 * 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 a52 * free slot from the bad blocks table to mark the setting range S. The53 * result is,54 * +-------------+ +--------+ +-------------+55 * | E1 | | S | | E2 |56 * +-------------+ +--------+ +-------------+57 * 2) A setting range starts exactly at a start LBA of an already set bad blocks58 * range.59 * 2.1) The setting range size < already set range size60 * +--------+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 can67 * 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, and72 * 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 head78 * 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 size83 * 2.2.1) If S and E are both acked or unacked range, the setting range S can84 * 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, and89 * 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 of94 bad blocks range E. The result is,95 * +-------------+96 * | S |97 * +-------------+98 * 2.3) The setting range size > already set range size99 * +-------------------+100 * | S |101 * +-------------------+102 * +-------------+103 * | E |104 * +-------------+105 * For such situation, the setting range S can be treated as two parts, the106 * first part (S1) is as same size as the already set range E, the second107 * 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 set115 * range E, which are already explained in 2.2), for the rest S2 it will be116 * handled later in next loop.117 * 3) A setting range starts before the start LBA of an already set bad blocks118 * range.119 * +-------------+120 * | S |121 * +-------------+122 * +-------------+123 * | E |124 * +-------------+125 * For this situation, the setting range S can be divided into two parts, the126 * first (S1) ends at the start LBA of already set range E, the second part127 * (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 in135 * similar condition as 1). The rest part S2 has exact same start LBA address136 * of the already set range E, they will be handled in next loop in one of137 * situations in 2).138 * 4) A setting range starts after the start LBA of an already set bad blocks139 * range.140 * 4.1) If the setting range S exactly matches the tail part of already set bad141 * 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 setting154 * 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 may159 * 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, like164 * 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 setting177 * 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 will182 * inserted into middle of E and split previous range E into two parts (E1183 * 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 bad188 * blocks range E. The range S starts after the start LBA of range E, and189 * 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 first197 * part (S1) ends at end range E, and the second part (S2) has rest range of198 * 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 be206 * handled as the situations 4.1), the rest range S2 will be handled in next207 * loop and ignored in this loop.208 * 5) A setting bad blocks range S is adjacent to one or more already set bad209 * 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 setting211 * 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 acknowledge219 * values are same, the setting range S can front merges into range E. The220 * result is,221 * +--------------+222 * | S |223 * +--------------+224 * 5.1.2) Otherwise these two ranges cannot merge, just insert the setting225 * range S right after already set range E into the bad blocks table. The226 * result is,227 * +--------+------+228 * | E | S |229 * +--------+------+230 * 6) Special cases which above conditions cannot handle231 * 6.1) Multiple already set ranges may merge into less ones in a full bad table232 * +-------------------------------------------------------+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 the240 * first part of setting range S will fail because no more available slot241 * can be allocated from bad blocks table. In this situation a proper242 * setting method should be go though all the setting bad blocks range and243 * look for chance to merge already set ranges into less ones. When there244 * is available slot from bad blocks table, re-try again to handle more245 * 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 due254 * to no-space in bad blocks table, but the following E1, E2 and E3 ranges255 * can be merged with rest part of S into less range S1 and S2. Now there is256 * 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 the261 * origin setting range S. Now the setting range S3 can be inserted into the262 * bad blocks table with previous freed slot from multiple ranges merge.263 * 6.2) Front merge after overwrite264 * In the following example, in bad blocks table, E1 is an acked bad blocks265 * range and E2 is an unacked bad blocks range, therefore they are not able266 * 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 | acknowledged270 * +--------+ S: 1271 * +-------+-------------+ E1: 1272 * | E1 | E2 | E2: 0273 * +-------+-------------+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 not276 * overwritten by S),277 * acknowledged278 * +-------+--------+----+ S: 1279 * | E1 | S | E3 | E1: 1280 * +-------+--------+----+ E3: 0281 * The above result is correct but not perfect. Range E1 and S in the bad282 * blocks table are all acked, merging them into a larger one range may283 * occupy less bad blocks table space and make badblocks_check() faster.284 * Therefore in such situation, after overwriting range S, the previous range285 * E1 should be checked for possible front combination. Then the ideal286 * result can be,287 * +----------------+----+ acknowledged288 * | E1 | E3 | E1: 1289 * +----------------+----+ E3: 0290 * 6.3) Behind merge: If the already set bad blocks range E is behind the setting291 * range S and they are adjacent. Normally we don't need to care about this292 * because front merge handles this while going though range S from head to293 * tail, except for the tail part of range S. When the setting range S are294 * fully handled, all the above simplified routine doesn't check whether the295 * tail LBA of range S is adjacent to the next already set range and not296 * 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 handled304 * and the loop ends, an extra check is necessary for whether next already305 * 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 acknowledge307 * values are same, the setting range S can behind merges into range E. The308 * result is,309 * +--------------+310 * | S |311 * +--------------+312 * 6.3.2) Otherwise these two ranges cannot merge, just insert the setting range313 * S in front of the already set range E in the bad blocks table. The result314 * is,315 * +------+-------+316 * | S | E |317 * +------+-------+318 *319 * All the above 5 simplified situations and 3 special cases may cover 99%+ of320 * the bad block range setting conditions. Maybe there is some rare corner case321 * is not considered and optimized, it won't hurt if badblocks_set() fails due322 * 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, every325 * time for the new loop prev_badblocks() is called to find an already set range326 * which starts before or at current setting range. Since the setting bad blocks327 * range is handled from head to tail, most of the cases it is unnecessary to do328 * the binary search inside prev_badblocks(), it is possible to provide a hint329 * to prev_badblocks() for a fast path, then the expensive binary search can be330 * avoided. In my test with the hint to prev_badblocks(), except for the first331 * loop, all rested calls to prev_badblocks() can go into the fast path and332 * return correct bad blocks table index immediately.333 *334 *335 * Clearing a bad blocks range from the bad block table has similar idea as336 * setting does, but much more simpler. The only thing needs to be noticed is337 * when the clearing range hits middle of a bad block range, the existing bad338 * block range will split into two, and one more item should be added into the339 * bad block table. The simplified situations to be considered are, (The already340 * set bad blocks ranges in bad block table are naming with prefix E, and the341 * 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 block344 * 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 failure352 * happens, simply returns 0.353 * 2) The clearing range hits middle of an already setting bad blocks range in354 * 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 be362 * 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 range367 * from the bad block table.368 * 3.1) Partially covered at head part369 * +------------+370 * | C |371 * +------------+372 * +-----------------+373 * | E |374 * +-----------------+375 * For this situation, the overlapped already set range will update the376 * start LBA to end of C and shrink the range to BB_LEN(E) - BB_LEN(C). No377 * item deleted from bad block table. The result is,378 * +----+379 * | E1 |380 * +----+381 * 3.2) Exact fully covered382 * +-----------------+383 * | C |384 * +-----------------+385 * +-----------------+386 * | E |387 * +-----------------+388 * For this situation the whole bad blocks range E will be cleared and its389 * corresponded item is deleted from the bad block table.390 * 4) The clearing range exactly ends at same LBA as an already set bad block391 * range.392 * +-------+393 * | C |394 * +-------+395 * +-----------------+396 * | E |397 * +-----------------+398 * For the above situation, the already set range E is updated to shrink its399 * 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 block405 * range from the bad block table.406 * 5.1) The already set bad block range is front overlapped with the clearing407 * range.408 * +----------+409 * | C |410 * +----------+411 * +------------+412 * | E |413 * +------------+414 * For such situation, the clearing range C can be treated as two parts. The415 * first part ends at the start LBA of range E, and the second part starts at416 * 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 be424 * handled as condition 3.1) in next loop.425 * 5.2) The already set bad block range is behind overlaopped with the clearing426 * range.427 * +----------+428 * | C |429 * +----------+430 * +------------+431 * | E |432 * +------------+433 * For such situation, the clearing range C can be treated as two parts. The434 * first part C1 ends at same end LBA of range E, and the second part starts435 * 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), and443 * the second part clearing range C2 can be handled as condition 1) in next444 * loop.445 *446 * All bad blocks range clearing can be simplified into the above 5 situations447 * by only handling the head part of the clearing range in each run of the448 * while-loop. The idea is similar to bad blocks range setting but much449 * simpler.450 */451 452/*453 * Find the range starts at-or-before 's' from bad table. The search454 * starts from index 'hint' and stops at index 'hint_end' from the bad455 * table.456 */457static 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 provided477 * (hint >= 0) then search in the bad table from hint firstly. It is478 * very probably the wanted bad range can be found from the hint index,479 * then the unnecessary while-loop iteration can be avoided.480 */481static 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 else521 hi = mid;522 }523 524 if (BB_OFFSET(p[lo]) <= s)525 ret = lo;526out:527 return ret;528}529 530/*531 * Return 'true' if the range indicated by 'bad' can be backward merged532 * with the bad range (from the bad table) index by 'behind'.533 */534static 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 range551 * (from the bad table) indexed by 'behind'. The return value is merged552 * sectors from bad->len.553 */554static 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 forward577 * merged with the bad range (from the bad table) indexed by 'prev'.578 */579static 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 range594 * (from bad table) indexed by 'prev'. The return value is sectors595 * merged from bad->len.596 */597static 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 to624 * handle: If a bad range (indexed by 'prev' from bad table) exactly625 * starts as bad->start, and the bad range ahead of 'prev' (indexed by626 * 'prev - 1' from bad table) exactly ends at where 'prev' starts, and627 * the sum of their lengths does not exceed BB_MAX_LEN limitation, then628 * these two bad range (from bad table) can be combined.629 *630 * Return 'true' if bad ranges indexed by 'prev' and 'prev - 1' from bad631 * table can be combined.632 */633static 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 bad649 * table) into one larger bad range, and the new range is indexed by650 * 'prev - 1'.651 * The caller of front_combine() will decrease bb->count, therefore652 * it is unnecessary to clear p[perv] after front merge.653 */654static 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 forward667 * overlapped with the bad range (from bad table) indexed by 'front'.668 * Exactly forward overlap means the bad range (from bad table) indexed669 * by 'prev' does not cover the whole range indicated by 'bad'.670 */671static 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 backward684 * overlapped with the bad range (from bad table) indexed by 'behind'.685 */686static 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 bad699 * range (from bad table) indexed by 'prev'.700 *701 * The range indicated by 'bad' can overwrite the bad range indexed by702 * 'prev' when,703 * 1) The whole range indicated by 'bad' can cover partial or whole bad704 * range (from bad table) indexed by 'prev'.705 * 2) The ack value of 'bad' is larger or equal to the ack value of bad706 * 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, 1711 * extra bad range will be split and added into the bad table.712 * 2) The overwrite covers middle of existing bad range, 2 extra bad713 * ranges will be split (ahead and after the overwritten range) and714 * added into the bad table.715 * The number of extra split ranges of the overwriting is stored in716 * 'extra' and returned for the caller.717 */718static 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 else734 *extra = 1;735 736 bad->len = len;737 } else {738 if (BB_OFFSET(p[prev]) == bad->start)739 *extra = 1;740 else741 /*742 * prev range will be split into two, beside the overwritten743 * 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 range756 * (from bad table) indexed by 'prev'.757 * The previously called can_front_overwrite() will provide how many758 * extra bad range(s) might be split and added into the bad table. All759 * the splitting cases in the bad table will be handled here.760 */761static 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 one789 * 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 one803 * 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, where821 * the location is indexed by 'at'.822 */823static 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 838static 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 */859static 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 895re_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 1011update_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 be1022 * 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 1048out:1049 if (added) {1050 set_changed(bb);1051 1052 if (!acknowledged)1053 bb->unacked_exist = 1;1054 else1055 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 overlapped1068 * with the clearing range. The return value is how many sectors from an1069 * already set bad block range are cleared. If the whole bad block range is1070 * covered by the clearing range and fully cleared, 'delete' is set as 1 for1071 * the caller to reduce bb->count.1072 */1073static 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 set1113 * bad block range from bad block table. In this condition the existing bad1114 * block range is split into two after the middle part is cleared.1115 */1116static 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 */1134static 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 with1155 * the block size and no rounding should ever be needed.1156 * However it is better the think a block is bad when it1157 * 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 1170re_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 successful1194 */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 1251update_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 */1274static 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 1296retry:1297 seq = read_seqbegin(&bb->lock);1298 1299 p = bb->page;1300 unacked_badblocks = 0;1301 acked_badblocks = 0;1302 1303re_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 else1326 unacked_badblocks++;1327 1328 if (BB_END(p[prev]) >= (s + sectors))1329 len = sectors;1330 else1331 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 1351update_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 else1365 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 sectors1375 * @bb: the badblocks structure that holds all badblock information1376 * @s: sector (start) at which to check for badblocks1377 * @sectors: number of sectors to check for badblocks1378 * @first_bad: pointer to store location of the first badblock1379 * @bad_sectors: pointer to store number of badblocks after @first_bad1380 *1381 * We can record which blocks on each device are 'bad' and so just1382 * 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 1-5121385 * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes)1386 * A 'shift' can be set so that larger blocks are tracked and1387 * 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_check1391 * 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 to1396 * know if any block in the range is bad. So we binary-search1397 * 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 range1403 * 1: there are known bad block which are all acknowledged1404 * -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 */1407int 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}1412EXPORT_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 information1417 * @s: first sector to mark as bad1418 * @sectors: number of sectors to mark as bad1419 * @acknowledged: weather to mark the bad sectors as acknowledged1420 *1421 * This might extend the table, or might contract it if two adjacent ranges1422 * can be merged. We binary-search to find the 'insertion' point, then1423 * decide how best to handle it.1424 *1425 * Return:1426 * 0: success1427 * 1: failed to set badblocks (out of space)1428 */1429int badblocks_set(struct badblocks *bb, sector_t s, int sectors,1430 int acknowledged)1431{1432 return _badblocks_set(bb, s, sectors, acknowledged);1433}1434EXPORT_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 information1439 * @s: first sector to mark as bad1440 * @sectors: number of sectors to mark as bad1441 *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 just1444 * drop the remove request.1445 *1446 * Return:1447 * 0: success1448 * 1: failed to clear badblocks1449 */1450int badblocks_clear(struct badblocks *bb, sector_t s, int sectors)1451{1452 return _badblocks_clear(bb, s, sectors);1453}1454EXPORT_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 information1459 *1460 * This only succeeds if ->changed is clear. It is used by1461 * in-kernel metadata updates1462 */1463void 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}1486EXPORT_SYMBOL_GPL(ack_all_badblocks);1487 1488/**1489 * badblocks_show() - sysfs access to bad-blocks list1490 * @bb: the badblocks structure that holds all badblock information1491 * @page: buffer received from sysfs1492 * @unack: weather to show unacknowledged badblocks1493 *1494 * Return:1495 * Length of returned data1496 */1497ssize_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 1507retry: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}1535EXPORT_SYMBOL_GPL(badblocks_show);1536 1537/**1538 * badblocks_store() - sysfs access to bad-blocks list1539 * @bb: the badblocks structure that holds all badblock information1540 * @page: buffer received from sysfs1541 * @len: length of data received from sysfs1542 * @unack: weather to show unacknowledged badblocks1543 *1544 * Return:1545 * Length of the buffer processed or -ve error.1546 */1547ssize_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 else1570 return len;1571}1572EXPORT_SYMBOL_GPL(badblocks_store);1573 1574static 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 else1582 bb->shift = -1;1583 if (dev)1584 bb->page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL);1585 else1586 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 structure1598 * @bb: the badblocks structure that holds all badblock information1599 * @enable: weather to enable badblocks accounting1600 *1601 * Return:1602 * 0: success1603 * -ve errno: on error1604 */1605int badblocks_init(struct badblocks *bb, int enable)1606{1607 return __badblocks_init(NULL, bb, enable);1608}1609EXPORT_SYMBOL_GPL(badblocks_init);1610 1611int devm_init_badblocks(struct device *dev, struct badblocks *bb)1612{1613 if (!bb)1614 return -EINVAL;1615 return __badblocks_init(dev, bb, 1);1616}1617EXPORT_SYMBOL_GPL(devm_init_badblocks);1618 1619/**1620 * badblocks_exit() - free the badblocks structure1621 * @bb: the badblocks structure that holds all badblock information1622 */1623void badblocks_exit(struct badblocks *bb)1624{1625 if (!bb)1626 return;1627 if (bb->dev)1628 devm_kfree(bb->dev, bb->page);1629 else1630 kfree(bb->page);1631 bb->page = NULL;1632}1633EXPORT_SYMBOL_GPL(badblocks_exit);1634