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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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SPDX-License-Identifier: GPL-2.0/* * Bad block management * * - Heavily based on MD badblocks code from Neil Brown * * Copyright (c) 2015, Intel Corporation. */
#include <linux/badblocks.h>#include <linux/seqlock.h>#include <linux/device.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/stddef.h>#include <linux/types.h>#include <linux/slab.h>
/* * The purpose of badblocks set/clear is to manage bad blocks ranges which are * identified by LBA addresses. * * When the caller of badblocks_set() wants to set a range of bad blocks, the * setting range can be acked or unacked. And the setting range may merge, * overwrite, skip the overlapped already set range, depends on who they are * overlapped or adjacent, and the acknowledgment type of the ranges. It can be * more complicated when the setting range covers multiple already set bad block * ranges, with restrictions of maximum length of each bad range and the bad * table space limitation. * * It is difficult and unnecessary to take care of all the possible situations, * for setting a large range of bad blocks, we can handle it by dividing the * large range into smaller ones when encounter overlap, max range length or * bad table full conditions. Every time only a smaller piece of the bad range * is handled with a limited number of conditions how it is interacted with * possible overlapped or adjacent already set bad block ranges. Then the hard * complicated problem can be much simpler to handle in proper way. * * When setting a range of bad blocks to the bad table, the simplified situations * to be considered are, (The already set bad blocks ranges are naming with * prefix E, and the setting bad blocks range is naming with prefix S) * * 1) A setting range is not overlapped or adjacent to any other already set bad * block range. * +--------+ * | S | * +--------+ * +-------------+ +-------------+ * | E1 | | E2 | * +-------------+ +-------------+ * For this situation if the bad blocks table is not full, just allocate a * free slot from the bad blocks table to mark the setting range S. The * result is, * +-------------+ +--------+ +-------------+ * | E1 | | S | | E2 | * +-------------+ +--------+ +-------------+ * 2) A setting range starts exactly at a start LBA of an already set bad blocks * range. * 2.1) The setting range size < already set range size * +--------+ * | S | * +--------+ * +-------------+ * | E | * +-------------+ * 2.1.1) If S and E are both acked or unacked range, the setting range S can * be merged into existing bad range E. The result is, * +-------------+ * | S | * +-------------+ * 2.1.2) If S is unacked setting and E is acked, the setting will be denied, and * the result is, * +-------------+ * | E | * +-------------+ * 2.1.3) If S is acked setting and E is unacked, range S can overwrite on E. * An extra slot from the bad blocks table will be allocated for S, and head * of E will move to end of the inserted range S. The result is, * +--------+----+ * | S | E | * +--------+----+ * 2.2) The setting range size == already set range size * 2.2.1) If S and E are both acked or unacked range, the setting range S can * be merged into existing bad range E. The result is, * +-------------+ * | S | * +-------------+ * 2.2.2) If S is unacked setting and E is acked, the setting will be denied, and * the result is, * +-------------+ * | E | * +-------------+ * 2.2.3) If S is acked setting and E is unacked, range S can overwrite all of bad blocks range E. The result is, * +-------------+ * | S | * +-------------+ * 2.3) The setting range size > already set range size * +-------------------+ * | S | * +-------------------+ * +-------------+ * | E | * +-------------+ * For such situation, the setting range S can be treated as two parts, the * first part (S1) is as same size as the already set range E, the second * part (S2) is the rest of setting range. * +-------------+-----+ +-------------+ +-----+ * | S1 | S2 | | S1 | | S2 | * +-------------+-----+ ===> +-------------+ +-----+ * +-------------+ +-------------+ * | E | | E | * +-------------+ +-------------+ * Now we only focus on how to handle the setting range S1 and already set * range E, which are already explained in 2.2), for the rest S2 it will be * handled later in next loop. * 3) A setting range starts before the start LBA of an already set bad blocks * range. * +-------------+ * | S | * +-------------+ * +-------------+ * | E | * +-------------+ * For this situation, the setting range S can be divided into two parts, the * first (S1) ends at the start LBA of already set range E, the second part * (S2) starts exactly at a start LBA of the already set range E. * +----+---------+ +----+ +---------+ * | S1 | S2 | | S1 | | S2 | * +----+---------+ ===> +----+ +---------+ * +-------------+ +-------------+ * | E | | E | * +-------------+ +-------------+ * Now only the first part S1 should be handled in this loop, which is in * similar condition as 1). The rest part S2 has exact same start LBA address * of the already set range E, they will be handled in next loop in one of * situations in 2). * 4) A setting range starts after the start LBA of an already set bad blocks * range. * 4.1) If the setting range S exactly matches the tail part of already set bad * blocks range E, like the following chart shows, * +---------+ * | S | * +---------+ * +-------------+ * | E | * +-------------+ * 4.1.1) If range S and E have same acknowledge value (both acked or unacked), * they will be merged into one, the result is, * +-------------+ * | S | * +-------------+ * 4.1.2) If range E is acked and the setting range S is unacked, the setting * request of S will be rejected, the result is, * +-------------+ * | E | * +-------------+ * 4.1.3) If range E is unacked, and the setting range S is acked, then S may * overwrite the overlapped range of E, the result is, * +---+---------+ * | E | S | * +---+---------+ * 4.2) If the setting range S stays in middle of an already set range E, like * the following chart shows, * +----+ * | S | * +----+ * +--------------+ * | E | * +--------------+ * 4.2.1) If range S and E have same acknowledge value (both acked or unacked), * they will be merged into one, the result is, * +--------------+ * | S | * +--------------+ * 4.2.2) If range E is acked and the setting range S is unacked, the setting * request of S will be rejected, the result is also, * +--------------+ * | E | * +--------------+ * 4.2.3) If range E is unacked, and the setting range S is acked, then S will * inserted into middle of E and split previous range E into two parts (E1 * and E2), the result is, * +----+----+----+ * | E1 | S | E2 | * +----+----+----+ * 4.3) If the setting bad blocks range S is overlapped with an already set bad * blocks range E. The range S starts after the start LBA of range E, and * ends after the end LBA of range E, as the following chart shows, * +-------------------+ * | S | * +-------------------+ * +-------------+ * | E | * +-------------+ * For this situation the range S can be divided into two parts, the first * part (S1) ends at end range E, and the second part (S2) has rest range of * origin S. * +---------+---------+ +---------+ +---------+ * | S1 | S2 | | S1 | | S2 | * +---------+---------+ ===> +---------+ +---------+ * +-------------+ +-------------+ * | E | | E | * +-------------+ +-------------+ * Now in this loop the setting range S1 and already set range E can be * handled as the situations 4.1), the rest range S2 will be handled in next * loop and ignored in this loop. * 5) A setting bad blocks range S is adjacent to one or more already set bad * blocks range(s), and they are all acked or unacked range. * 5.1) Front merge: If the already set bad blocks range E is before setting * range S and they are adjacent, * +------+ * | S | * +------+ * +-------+ * | E | * +-------+ * 5.1.1) When total size of range S and E <= BB_MAX_LEN, and their acknowledge * values are same, the setting range S can front merges into range E. The * result is, * +--------------+ * | S | * +--------------+ * 5.1.2) Otherwise these two ranges cannot merge, just insert the setting * range S right after already set range E into the bad blocks table. The * result is, * +--------+------+ * | E | S | * +--------+------+ * 6) Special cases which above conditions cannot handle * 6.1) Multiple already set ranges may merge into less ones in a full bad table * +-------------------------------------------------------+ * | S | * +-------------------------------------------------------+ * |<----- BB_MAX_LEN ----->| * +-----+ +-----+ +-----+ * | E1 | | E2 | | E3 | * +-----+ +-----+ +-----+ * In the above example, when the bad blocks table is full, inserting the * first part of setting range S will fail because no more available slot * can be allocated from bad blocks table. In this situation a proper * setting method should be go though all the setting bad blocks range and * look for chance to merge already set ranges into less ones. When there * is available slot from bad blocks table, re-try again to handle more * setting bad blocks ranges as many as possible. * +------------------------+ * | S3 | * +------------------------+ * |<----- BB_MAX_LEN ----->| * +-----+-----+-----+---+-----+--+ * | S1 | S2 | * +-----+-----+-----+---+-----+--+ * The above chart shows although the first part (S3) cannot be inserted due * to no-space in bad blocks table, but the following E1, E2 and E3 ranges * can be merged with rest part of S into less range S1 and S2. Now there is * 1 free slot in bad blocks table. * +------------------------+-----+-----+-----+---+-----+--+ * | S3 | S1 | S2 | * +------------------------+-----+-----+-----+---+-----+--+ * Since the bad blocks table is not full anymore, re-try again for the * origin setting range S. Now the setting range S3 can be inserted into the * bad blocks table with previous freed slot from multiple ranges merge. * 6.2) Front merge after overwrite * In the following example, in bad blocks table, E1 is an acked bad blocks * range and E2 is an unacked bad blocks range, therefore they are not able * to merge into a larger range. The setting bad blocks range S is acked, * therefore part of E2 can be overwritten by S. * +--------+ * | S | acknowledged * +--------+ S: 1 * +-------+-------------+ E1: 1 * | E1 | E2 | E2: 0 * +-------+-------------+ * With previous simplified routines, after overwriting part of E2 with S, * the bad blocks table should be (E3 is remaining part of E2 which is not * overwritten by S), * acknowledged * +-------+--------+----+ S: 1 * | E1 | S | E3 | E1: 1 * +-------+--------+----+ E3: 0 * The above result is correct but not perfect. Range E1 and S in the bad * blocks table are all acked, merging them into a larger one range may * occupy less bad blocks table space and make badblocks_check() faster. * Therefore in such situation, after overwriting range S, the previous range * E1 should be checked for possible front combination. Then the ideal * result can be, * +----------------+----+ acknowledged * | E1 | E3 | E1: 1 * +----------------+----+ E3: 0 * 6.3) Behind merge: If the already set bad blocks range E is behind the setting * range S and they are adjacent. Normally we don't need to care about this * because front merge handles this while going though range S from head to * tail, except for the tail part of range S. When the setting range S are * fully handled, all the above simplified routine doesn't check whether the * tail LBA of range S is adjacent to the next already set range and not * merge them even it is possible. * +------+ * | S | * +------+ * +-------+ * | E | * +-------+ * For the above special situation, when the setting range S are all handled * and the loop ends, an extra check is necessary for whether next already * set range E is right after S and mergeable. * 6.3.1) When total size of range E and S <= BB_MAX_LEN, and their acknowledge * values are same, the setting range S can behind merges into range E. The * result is, * +--------------+ * | S | * +--------------+ * 6.3.2) Otherwise these two ranges cannot merge, just insert the setting range * S in front of the already set range E in the bad blocks table. The result * is, * +------+-------+ * | S | E | * +------+-------+ * * All the above 5 simplified situations and 3 special cases may cover 99%+ of * the bad block range setting conditions. Maybe there is some rare corner case * is not considered and optimized, it won't hurt if badblocks_set() fails due * to no space, or some ranges are not merged to save bad blocks table space. * * Inside badblocks_set() each loop starts by jumping to re_insert label, every * time for the new loop prev_badblocks() is called to find an already set range * which starts before or at current setting range. Since the setting bad blocks * range is handled from head to tail, most of the cases it is unnecessary to do * the binary search inside prev_badblocks(), it is possible to provide a hint * to prev_badblocks() for a fast path, then the expensive binary search can be * avoided. In my test with the hint to prev_badblocks(), except for the first * loop, all rested calls to prev_badblocks() can go into the fast path and * return correct bad blocks table index immediately. * * * Clearing a bad blocks range from the bad block table has similar idea as * setting does, but much more simpler. The only thing needs to be noticed is * when the clearing range hits middle of a bad block range, the existing bad * block range will split into two, and one more item should be added into the * bad block table. The simplified situations to be considered are, (The already * set bad blocks ranges in bad block table are naming with prefix E, and the * clearing bad blocks range is naming with prefix C) * * 1) A clearing range is not overlapped to any already set ranges in bad block * table. * +-----+ | +-----+ | +-----+ * | C | | | C | | | C | * +-----+ or +-----+ or +-----+ * +---+ | +----+ +----+ | +---+ * | E | | | E1 | | E2 | | | E | * +---+ | +----+ +----+ | +---+ * For the above situations, no bad block to be cleared and no failure * happens, simply returns 0. * 2) The clearing range hits middle of an already setting bad blocks range in * the bad block table. * +---+ * | C | * +---+ * +-----------------+ * | E | * +-----------------+ * In this situation if the bad block table is not full, the range E will be * split into two ranges E1 and E2. The result is, * +------+ +------+ * | E1 | | E2 | * +------+ +------+ * 3) The clearing range starts exactly at same LBA as an already set bad block range * from the bad block table. * 3.1) Partially covered at head part * +------------+ * | C | * +------------+ * +-----------------+ * | E | * +-----------------+ * For this situation, the overlapped already set range will update the * start LBA to end of C and shrink the range to BB_LEN(E) - BB_LEN(C). No * item deleted from bad block table. The result is, * +----+ * | E1 | * +----+ * 3.2) Exact fully covered * +-----------------+ * | C | * +-----------------+ * +-----------------+ * | E | * +-----------------+ * For this situation the whole bad blocks range E will be cleared and its * corresponded item is deleted from the bad block table. * 4) The clearing range exactly ends at same LBA as an already set bad block * range. * +-------+ * | C | * +-------+ * +-----------------+ * | E | * +-----------------+ * For the above situation, the already set range E is updated to shrink its * end to the start of C, and reduce its length to BB_LEN(E) - BB_LEN(C). * The result is, * +---------+ * | E | * +---------+ * 5) The clearing range is partially overlapped with an already set bad block * range from the bad block table. * 5.1) The already set bad block range is front overlapped with the clearing * range. * +----------+ * | C | * +----------+ * +------------+ * | E | * +------------+ * For such situation, the clearing range C can be treated as two parts. The * first part ends at the start LBA of range E, and the second part starts at * same LBA of range E. * +----+-----+ +----+ +-----+ * | C1 | C2 | | C1 | | C2 | * +----+-----+ ===> +----+ +-----+ * +------------+ +------------+ * | E | | E | * +------------+ +------------+ * Now the first part C1 can be handled as condition 1), and the second part C2 can be * handled as condition 3.1) in next loop. * 5.2) The already set bad block range is behind overlaopped with the clearing * range. * +----------+ * | C | * +----------+ * +------------+ * | E | * +------------+ * For such situation, the clearing range C can be treated as two parts. The * first part C1 ends at same end LBA of range E, and the second part starts * at end LBA of range E. * +----+-----+ +----+ +-----+ * | C1 | C2 | | C1 | | C2 | * +----+-----+ ===> +----+ +-----+ * +------------+ +------------+ * | E | | E | * +------------+ +------------+ * Now the first part clearing range C1 can be handled as condition 4), and * the second part clearing range C2 can be handled as condition 1) in next * loop. * * All bad blocks range clearing can be simplified into the above 5 situations * by only handling the head part of the clearing range in each run of the * while-loop. The idea is similar to bad blocks range setting but much * simpler. */
/* * Find the range starts at-or-before 's' from bad table. The search * starts from index 'hint' and stops at index 'hint_end' from the bad * table. */static int prev_by_hint(struct badblocks *bb, sector_t s, int hint){ int hint_end = hint + 2; u64 *p = bb->page; int ret = -1;
while ((hint < hint_end) && ((hint + 1) <= bb->count) && (BB_OFFSET(p[hint]) <= s)) { if ((hint + 1) == bb->count || BB_OFFSET(p[hint + 1]) > s) { ret = hint; break; } hint++; }
return ret;}
/* * Find the range starts at-or-before bad->start. If 'hint' is provided * (hint >= 0) then search in the bad table from hint firstly. It is * very probably the wanted bad range can be found from the hint index, * then the unnecessary while-loop iteration can be avoided. */static int prev_badblocks(struct badblocks *bb, struct badblocks_context *bad, int hint){ sector_t s = bad->start; int ret = -1; int lo, hi; u64 *p;
if (!bb->count) goto out;
if (hint >= 0) { ret = prev_by_hint(bb, s, hint); if (ret >= 0) goto out; }
lo = 0; hi = bb->count; p = bb->page;
/* The following bisect search might be unnecessary */ if (BB_OFFSET(p[lo]) > s) return -1; if (BB_OFFSET(p[hi - 1]) <= s) return hi - 1;
/* Do bisect search in bad table */ while (hi - lo > 1) { int mid = (lo + hi)/2; sector_t a = BB_OFFSET(p[mid]);
if (a == s) { ret = mid; goto out; }
if (a < s) lo = mid; else hi = mid; }
if (BB_OFFSET(p[lo]) <= s) ret = lo;out: return ret;}
/* * Return 'true' if the range indicated by 'bad' can be forward * merged with the bad range (from the bad table) indexed by 'prev'. */static bool can_merge_front(struct badblocks *bb, int prev, struct badblocks_context *bad){ sector_t s = bad->start; u64 *p = bb->page;
if (BB_ACK(p[prev]) == bad->ack && (s < BB_END(p[prev]) || (s == BB_END(p[prev]) && (BB_LEN(p[prev]) < BB_MAX_LEN)))) return true; return false;}
/* * Do forward merge for range indicated by 'bad' and the bad range * (from bad table) indexed by 'prev'. The return value is sectors * merged from bad->len. */static int front_merge(struct badblocks *bb, int prev, struct badblocks_context *bad){ sector_t sectors = bad->len; sector_t s = bad->start; u64 *p = bb->page; int merged = 0;
WARN_ON(s > BB_END(p[prev]));
if (s < BB_END(p[prev])) { merged = min_t(sector_t, sectors, BB_END(p[prev]) - s); } else { merged = min_t(sector_t, sectors, BB_MAX_LEN - BB_LEN(p[prev])); if ((prev + 1) < bb->count && merged > (BB_OFFSET(p[prev + 1]) - BB_END(p[prev]))) { merged = BB_OFFSET(p[prev + 1]) - BB_END(p[prev]); }
p[prev] = BB_MAKE(BB_OFFSET(p[prev]), BB_LEN(p[prev]) + merged, bad->ack); }
return merged;}
/* * 'Combine' is a special case which can_merge_front() is not able to * handle: If a bad range (indexed by 'prev' from bad table) exactly * starts as bad->start, and the bad range ahead of 'prev' (indexed by * 'prev - 1' from bad table) exactly ends at where 'prev' starts, and * the sum of their lengths does not exceed BB_MAX_LEN limitation, then * these two bad range (from bad table) can be combined. * * Return 'true' if bad ranges indexed by 'prev' and 'prev - 1' from bad * table can be combined. */static bool can_combine_front(struct badblocks *bb, int prev, struct badblocks_context *bad){ u64 *p = bb->page;
if ((prev > 0) && (BB_OFFSET(p[prev]) == bad->start) && (BB_END(p[prev - 1]) == BB_OFFSET(p[prev])) && (BB_LEN(p[prev - 1]) + BB_LEN(p[prev]) <= BB_MAX_LEN) && (BB_ACK(p[prev - 1]) == BB_ACK(p[prev]))) return true; return false;}
/* * Combine the bad ranges indexed by 'prev' and 'prev - 1' (from bad * table) into one larger bad range, and the new range is indexed by * 'prev - 1'. * The caller of front_combine() will decrease bb->count, therefore * it is unnecessary to clear p[perv] after front merge. */static void front_combine(struct badblocks *bb, int prev){ u64 *p = bb->page;
p[prev - 1] = BB_MAKE(BB_OFFSET(p[prev - 1]), BB_LEN(p[prev - 1]) + BB_LEN(p[prev]), BB_ACK(p[prev])); if ((prev + 1) < bb->count) memmove(p + prev, p + prev + 1, (bb->count - prev - 1) * 8);}
/* * Return 'true' if the range indicated by 'bad' is exactly forward * overlapped with the bad range (from bad table) indexed by 'front'. * Exactly forward overlap means the bad range (from bad table) indexed * by 'prev' does not cover the whole range indicated by 'bad'. */static bool overlap_front(struct badblocks *bb, int front, struct badblocks_context *bad){ u64 *p = bb->page;
if (bad->start >= BB_OFFSET(p[front]) && bad->start < BB_END(p[front])) return true; return false;}
/* * Return 'true' if the range indicated by 'bad' is exactly backward * overlapped with the bad range (from bad table) indexed by 'behind'. */static bool overlap_behind(struct badblocks *bb, struct badblocks_context *bad, int behind){ u64 *p = bb->page;
if (bad->start < BB_OFFSET(p[behind]) && (bad->start + bad->len) > BB_OFFSET(p[behind])) return true; return false;}
/* * Return 'true' if the range indicated by 'bad' can overwrite the bad * range (from bad table) indexed by 'prev'. * * The range indicated by 'bad' can overwrite the bad range indexed by * 'prev' when, * 1) The whole range indicated by 'bad' can cover partial or whole bad * range (from bad table) indexed by 'prev'. * 2) The ack value of 'bad' is larger or equal to the ack value of bad * range 'prev'. * * If the overwriting doesn't cover the whole bad range (from bad table) * indexed by 'prev', new range might be split from existing bad range, * 1) The overwrite covers head or tail part of existing bad range, 1 * extra bad range will be split and added into the bad table. * 2) The overwrite covers middle of existing bad range, 2 extra bad * ranges will be split (ahead and after the overwritten range) and * added into the bad table. * The number of extra split ranges of the overwriting is stored in * 'extra' and returned for the caller. */static bool can_front_overwrite(struct badblocks *bb, int prev, struct badblocks_context *bad, int *extra){ u64 *p = bb->page; int len;
WARN_ON(!overlap_front(bb, prev, bad));
if (BB_ACK(p[prev]) >= bad->ack) return false;
if (BB_END(p[prev]) <= (bad->start + bad->len)) { len = BB_END(p[prev]) - bad->start; if (BB_OFFSET(p[prev]) == bad->start) *extra = 0; else *extra = 1;
bad->len = len; } else { if (BB_OFFSET(p[prev]) == bad->start) *extra = 1; else /* * prev range will be split into two, beside the overwritten * one, an extra slot needed from bad table. */ *extra = 2; }
if ((bb->count + (*extra)) > MAX_BADBLOCKS) return false;
return true;}
/* * Do the overwrite from the range indicated by 'bad' to the bad range * (from bad table) indexed by 'prev'. * The previously called can_front_overwrite() will provide how many * extra bad range(s) might be split and added into the bad table. All * the splitting cases in the bad table will be handled here. */static int front_overwrite(struct badblocks *bb, int prev, struct badblocks_context *bad, int extra){ u64 *p = bb->page; sector_t orig_end = BB_END(p[prev]); int orig_ack = BB_ACK(p[prev]);
switch (extra) { case 0: p[prev] = BB_MAKE(BB_OFFSET(p[prev]), BB_LEN(p[prev]), bad->ack); break; case 1: if (BB_OFFSET(p[prev]) == bad->start) { p[prev] = BB_MAKE(BB_OFFSET(p[prev]), bad->len, bad->ack); memmove(p + prev + 2, p + prev + 1, (bb->count - prev - 1) * 8); p[prev + 1] = BB_MAKE(bad->start + bad->len, orig_end - BB_END(p[prev]), orig_ack); } else { p[prev] = BB_MAKE(BB_OFFSET(p[prev]), bad->start - BB_OFFSET(p[prev]), orig_ack); /* * prev +2 -> prev + 1 + 1, which is for, * 1) prev + 1: the slot index of the previous one * 2) + 1: one more slot for extra being 1. */ memmove(p + prev + 2, p + prev + 1, (bb->count - prev - 1) * 8); p[prev + 1] = BB_MAKE(bad->start, bad->len, bad->ack); } break; case 2: p[prev] = BB_MAKE(BB_OFFSET(p[prev]), bad->start - BB_OFFSET(p[prev]), orig_ack); /* * prev + 3 -> prev + 1 + 2, which is for, * 1) prev + 1: the slot index of the previous one * 2) + 2: two more slots for extra being 2. */ memmove(p + prev + 3, p + prev + 1, (bb->count - prev - 1) * 8); p[prev + 1] = BB_MAKE(bad->start, bad->len, bad->ack); p[prev + 2] = BB_MAKE(BB_END(p[prev + 1]), orig_end - BB_END(p[prev + 1]), orig_ack); break; default: break; }
return bad->len;}
/* * Explicitly insert a range indicated by 'bad' to the bad table, where * the location is indexed by 'at'. */static int insert_at(struct badblocks *bb, int at, struct badblocks_context *bad){ u64 *p = bb->page; int len;
WARN_ON(badblocks_full(bb));
len = min_t(sector_t, bad->len, BB_MAX_LEN); if (at < bb->count) memmove(p + at + 1, p + at, (bb->count - at) * 8); p[at] = BB_MAKE(bad->start, len, bad->ack);
return len;}
static void badblocks_update_acked(struct badblocks *bb){ bool unacked = false; u64 *p = bb->page; int i;
if (!bb->unacked_exist) return;
for (i = 0; i < bb->count ; i++) { if (!BB_ACK(p[i])) { unacked = true; break; } }
if (!unacked) bb->unacked_exist = 0;}
/* * Return 'true' if the range indicated by 'bad' is exactly backward * overlapped with the bad range (from bad table) indexed by 'behind'. */static bool try_adjacent_combine(struct badblocks *bb, int prev){ u64 *p = bb->page;
if (prev >= 0 && (prev + 1) < bb->count && BB_END(p[prev]) == BB_OFFSET(p[prev + 1]) && (BB_LEN(p[prev]) + BB_LEN(p[prev + 1])) <= BB_MAX_LEN && BB_ACK(p[prev]) == BB_ACK(p[prev + 1])) { p[prev] = BB_MAKE(BB_OFFSET(p[prev]), BB_LEN(p[prev]) + BB_LEN(p[prev + 1]), BB_ACK(p[prev]));
if ((prev + 2) < bb->count) memmove(p + prev + 1, p + prev + 2, (bb->count - (prev + 2)) * 8); bb->count--; return true; } return false;}
/* Do exact work to set bad block range into the bad block table */static bool _badblocks_set(struct badblocks *bb, sector_t s, sector_t sectors, int acknowledged){ int len = 0, added = 0; struct badblocks_context bad; int prev = -1, hint = -1; unsigned long flags; u64 *p;
if (bb->shift < 0) /* badblocks are disabled */ return false;
if (sectors == 0) /* Invalid sectors number */ return false;
if (bb->shift) { /* round the start down, and the end up */ sector_t next = s + sectors;
rounddown(s, 1 << bb->shift); roundup(next, 1 << bb->shift); sectors = next - s; }
write_seqlock_irqsave(&bb->lock, flags);
bad.ack = acknowledged; p = bb->page;
re_insert: bad.start = s; bad.len = sectors; len = 0;
if (badblocks_full(bb)) goto out;
if (badblocks_empty(bb)) { len = insert_at(bb, 0, &bad); bb->count++; added++; goto update_sectors; }
prev = prev_badblocks(bb, &bad, hint);
/* start before all badblocks */ if (prev < 0) { /* insert on the first */ if (bad.len > (BB_OFFSET(p[0]) - bad.start)) bad.len = BB_OFFSET(p[0]) - bad.start; len = insert_at(bb, 0, &bad); bb->count++; added++; hint = ++prev; goto update_sectors; }
/* in case p[prev-1] can be merged with p[prev] */ if (can_combine_front(bb, prev, &bad)) { front_combine(bb, prev); bb->count--; added++; hint = prev; goto update_sectors; }
if (can_merge_front(bb, prev, &bad)) { len = front_merge(bb, prev, &bad); added++; hint = prev; goto update_sectors; }
if (overlap_front(bb, prev, &bad)) { int extra = 0;
if (!can_front_overwrite(bb, prev, &bad, &extra)) { if (extra > 0) goto out;
len = min_t(sector_t, BB_END(p[prev]) - s, sectors); hint = prev; goto update_sectors; }
len = front_overwrite(bb, prev, &bad, extra); added++; bb->count += extra;
if (can_combine_front(bb, prev, &bad)) { front_combine(bb, prev); bb->count--; }
hint = prev; goto update_sectors; }
/* cannot merge and there is space in bad table */ if ((prev + 1) < bb->count && overlap_behind(bb, &bad, prev + 1)) bad.len = min_t(sector_t, bad.len, BB_OFFSET(p[prev + 1]) - bad.start);
len = insert_at(bb, prev + 1, &bad); bb->count++; added++; hint = ++prev;
update_sectors: s += len; sectors -= len;
if (sectors > 0) goto re_insert;
/* * Check whether the following already set range can be * merged. (prev < 0) condition is not handled here, * because it's already complicated enough. */ try_adjacent_combine(bb, prev);
out: if (added) { set_changed(bb);
if (!acknowledged) bb->unacked_exist = 1; else badblocks_update_acked(bb); }
write_sequnlock_irqrestore(&bb->lock, flags);
return sectors == 0;}
/* * Clear the bad block range from bad block table which is front overlapped * with the clearing range. The return value is how many sectors from an * already set bad block range are cleared. If the whole bad block range is * covered by the clearing range and fully cleared, 'delete' is set as 1 for * the caller to reduce bb->count. */static int front_clear(struct badblocks *bb, int prev, struct badblocks_context *bad, int *deleted){ sector_t sectors = bad->len; sector_t s = bad->start; u64 *p = bb->page; int cleared = 0;
*deleted = 0; if (s == BB_OFFSET(p[prev])) { if (BB_LEN(p[prev]) > sectors) { p[prev] = BB_MAKE(BB_OFFSET(p[prev]) + sectors, BB_LEN(p[prev]) - sectors, BB_ACK(p[prev])); cleared = sectors; } else { /* BB_LEN(p[prev]) <= sectors */ cleared = BB_LEN(p[prev]); if ((prev + 1) < bb->count) memmove(p + prev, p + prev + 1, (bb->count - prev - 1) * 8); *deleted = 1; } } else if (s > BB_OFFSET(p[prev])) { if (BB_END(p[prev]) <= (s + sectors)) { cleared = BB_END(p[prev]) - s; p[prev] = BB_MAKE(BB_OFFSET(p[prev]), s - BB_OFFSET(p[prev]), BB_ACK(p[prev])); } else { /* Splitting is handled in front_splitting_clear() */ BUG(); } }
return cleared;}
/* * Handle the condition that the clearing range hits middle of an already set * bad block range from bad block table. In this condition the existing bad * block range is split into two after the middle part is cleared. */static int front_splitting_clear(struct badblocks *bb, int prev, struct badblocks_context *bad){ u64 *p = bb->page; u64 end = BB_END(p[prev]); int ack = BB_ACK(p[prev]); sector_t sectors = bad->len; sector_t s = bad->start;
p[prev] = BB_MAKE(BB_OFFSET(p[prev]), s - BB_OFFSET(p[prev]), ack); memmove(p + prev + 2, p + prev + 1, (bb->count - prev - 1) * 8); p[prev + 1] = BB_MAKE(s + sectors, end - s - sectors, ack); return sectors;}
/* Do the exact work to clear bad block range from the bad block table */static bool _badblocks_clear(struct badblocks *bb, sector_t s, sector_t sectors){ struct badblocks_context bad; int prev = -1, hint = -1; int len = 0, cleared = 0; u64 *p;
if (bb->shift < 0) /* badblocks are disabled */ return false;
if (sectors == 0) /* Invalid sectors number */ return false;
if (bb->shift) { sector_t target;
/* When clearing we round the start up and the end down. * This should not matter as the shift should align with * the block size and no rounding should ever be needed. * However it is better the think a block is bad when it * isn't than to think a block is not bad when it is. */ target = s + sectors; roundup(s, 1 << bb->shift); rounddown(target, 1 << bb->shift); sectors = target - s; }
write_seqlock_irq(&bb->lock);
bad.ack = true; p = bb->page;
re_clear: bad.start = s; bad.len = sectors;
if (badblocks_empty(bb)) { len = sectors; cleared++; goto update_sectors; }
prev = prev_badblocks(bb, &bad, hint);
/* Start before all badblocks */ if (prev < 0) { if (overlap_behind(bb, &bad, 0)) { len = BB_OFFSET(p[0]) - s; hint = 0; } else { len = sectors; } /* * Both situations are to clear non-bad range, * should be treated as successful */ cleared++; goto update_sectors; }
/* Start after all badblocks */ if ((prev + 1) >= bb->count && !overlap_front(bb, prev, &bad)) { len = sectors; cleared++; goto update_sectors; }
/* Clear will split a bad record but the table is full */ if (badblocks_full(bb) && (BB_OFFSET(p[prev]) < bad.start) && (BB_END(p[prev]) > (bad.start + sectors))) { len = sectors; goto update_sectors; }
if (overlap_front(bb, prev, &bad)) { if ((BB_OFFSET(p[prev]) < bad.start) && (BB_END(p[prev]) > (bad.start + bad.len))) { /* Splitting */ if ((bb->count + 1) <= MAX_BADBLOCKS) { len = front_splitting_clear(bb, prev, &bad); bb->count += 1; cleared++; } else { /* No space to split, give up */ len = sectors; } } else { int deleted = 0;
len = front_clear(bb, prev, &bad, &deleted); bb->count -= deleted; cleared++; hint = prev; }
goto update_sectors; }
/* Not front overlap, but behind overlap */ if ((prev + 1) < bb->count && overlap_behind(bb, &bad, prev + 1)) { len = BB_OFFSET(p[prev + 1]) - bad.start; hint = prev + 1; /* Clear non-bad range should be treated as successful */ cleared++; goto update_sectors; }
/* Not cover any badblocks range in the table */ len = sectors; /* Clear non-bad range should be treated as successful */ cleared++;
update_sectors: s += len; sectors -= len;
if (sectors > 0) goto re_clear;
if (cleared) { badblocks_update_acked(bb); set_changed(bb); }
write_sequnlock_irq(&bb->lock);
if (!cleared) return false;
return true;}
/* Do the exact work to check bad blocks range from the bad block table */static int _badblocks_check(struct badblocks *bb, sector_t s, sector_t sectors, sector_t *first_bad, sector_t *bad_sectors){ int prev = -1, hint = -1, set = 0; struct badblocks_context bad; int unacked_badblocks = 0; int acked_badblocks = 0; u64 *p = bb->page; int len, rv;
re_check: bad.start = s; bad.len = sectors;
if (badblocks_empty(bb)) { len = sectors; goto update_sectors; }
prev = prev_badblocks(bb, &bad, hint);
/* start after all badblocks */ if ((prev >= 0) && ((prev + 1) >= bb->count) && !overlap_front(bb, prev, &bad)) { len = sectors; goto update_sectors; }
/* Overlapped with front badblocks record */ if ((prev >= 0) && overlap_front(bb, prev, &bad)) { if (BB_ACK(p[prev])) acked_badblocks++; else unacked_badblocks++;
if (BB_END(p[prev]) >= (s + sectors)) len = sectors; else len = BB_END(p[prev]) - s;
if (set == 0) { *first_bad = BB_OFFSET(p[prev]); *bad_sectors = BB_LEN(p[prev]); set = 1; } goto update_sectors; }
/* Not front overlap, but behind overlap */ if ((prev + 1) < bb->count && overlap_behind(bb, &bad, prev + 1)) { len = BB_OFFSET(p[prev + 1]) - bad.start; hint = prev + 1; goto update_sectors; }
/* not cover any badblocks range in the table */ len = sectors;
update_sectors: /* This situation should never happen */ WARN_ON(sectors < len);
s += len; sectors -= len;
if (sectors > 0) goto re_check;
if (unacked_badblocks > 0) rv = -1; else if (acked_badblocks > 0) rv = 1; else rv = 0;
return rv;}
/** * badblocks_check() - check a given range for bad sectors * @bb: the badblocks structure that holds all badblock information * @s: sector (start) at which to check for badblocks * @sectors: number of sectors to check for badblocks * @first_bad: pointer to store location of the first badblock * @bad_sectors: pointer to store number of badblocks after @first_bad * * We can record which blocks on each device are 'bad' and so just * fail those blocks, or that stripe, rather than the whole device. * Entries in the bad-block table are 64bits wide. This comprises: * Length of bad-range, in sectors: 0-511 for lengths 1-512 * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes) * A 'shift' can be set so that larger blocks are tracked and * consequently larger devices can be covered. * 'Acknowledged' flag - 1 bit. - the most significant bit. * * Locking of the bad-block table uses a seqlock so badblocks_check * might need to retry if it is very unlucky. * We will sometimes want to check for bad blocks in a bi_end_io function, * so we use the write_seqlock_irq variant. * * When looking for a bad block we specify a range and want to * know if any block in the range is bad. So we binary-search * to the last range that starts at-or-before the given endpoint, * (or "before the sector after the target range") * then see if it ends after the given start. * * Return: * 0: there are no known bad blocks in the range * 1: there are known bad block which are all acknowledged * -1: there are bad blocks which have not yet been acknowledged in metadata. * plus the start/length of the first bad section we overlap. */int badblocks_check(struct badblocks *bb, sector_t s, sector_t sectors, sector_t *first_bad, sector_t *bad_sectors){ unsigned int seq; int rv;
WARN_ON(bb->shift < 0 || sectors == 0);
if (bb->shift > 0) { /* round the start down, and the end up */ sector_t target = s + sectors;
rounddown(s, 1 << bb->shift); roundup(target, 1 << bb->shift); sectors = target - s; }
retry: seq = read_seqbegin(&bb->lock); rv = _badblocks_check(bb, s, sectors, first_bad, bad_sectors); if (read_seqretry(&bb->lock, seq)) goto retry;
return rv;}EXPORT_SYMBOL_GPL(badblocks_check);
/** * badblocks_set() - Add a range of bad blocks to the table. * @bb: the badblocks structure that holds all badblock information * @s: first sector to mark as bad * @sectors: number of sectors to mark as bad * @acknowledged: weather to mark the bad sectors as acknowledged * * This might extend the table, or might contract it if two adjacent ranges * can be merged. We binary-search to find the 'insertion' point, then * decide how best to handle it. * * Return: * true: success * false: failed to set badblocks (out of space). Parital setting will be * treated as failure. */bool badblocks_set(struct badblocks *bb, sector_t s, sector_t sectors, int acknowledged){ return _badblocks_set(bb, s, sectors, acknowledged);}EXPORT_SYMBOL_GPL(badblocks_set);
/** * badblocks_clear() - Remove a range of bad blocks to the table. * @bb: the badblocks structure that holds all badblock information * @s: first sector to mark as bad * @sectors: number of sectors to mark as bad * * This may involve extending the table if we spilt a region, * but it must not fail. So if the table becomes full, we just * drop the remove request. * * Return: * true: success * false: failed to clear badblocks */bool badblocks_clear(struct badblocks *bb, sector_t s, sector_t sectors){ return _badblocks_clear(bb, s, sectors);}EXPORT_SYMBOL_GPL(badblocks_clear);
/** * ack_all_badblocks() - Acknowledge all bad blocks in a list. * @bb: the badblocks structure that holds all badblock information * * This only succeeds if ->changed is clear. It is used by * in-kernel metadata updates */void ack_all_badblocks(struct badblocks *bb){ if (bb->page == NULL || bb->changed) /* no point even trying */ return; write_seqlock_irq(&bb->lock);
if (bb->changed == 0 && bb->unacked_exist) { u64 *p = bb->page; int i;
for (i = 0; i < bb->count ; i++) { if (!BB_ACK(p[i])) { sector_t start = BB_OFFSET(p[i]); int len = BB_LEN(p[i]);
p[i] = BB_MAKE(start, len, 1); } }
for (i = 0; i < bb->count ; i++) while (try_adjacent_combine(bb, i)) ;
bb->unacked_exist = 0; } write_sequnlock_irq(&bb->lock);}EXPORT_SYMBOL_GPL(ack_all_badblocks);
/** * badblocks_show() - sysfs access to bad-blocks list * @bb: the badblocks structure that holds all badblock information * @page: buffer received from sysfs * @unack: weather to show unacknowledged badblocks * * Return: * Length of returned data */ssize_t badblocks_show(struct badblocks *bb, char *page, int unack){ size_t len; int i; u64 *p = bb->page; unsigned seq;
if (bb->shift < 0) return 0;
retry: seq = read_seqbegin(&bb->lock);
len = 0; i = 0;
while (len < PAGE_SIZE && i < bb->count) { sector_t s = BB_OFFSET(p[i]); unsigned int length = BB_LEN(p[i]); int ack = BB_ACK(p[i]);
i++;
if (unack && ack) continue;
len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n", (unsigned long long)s << bb->shift, length << bb->shift); } if (unack && len == 0) bb->unacked_exist = 0;
if (read_seqretry(&bb->lock, seq)) goto retry;
return len;}EXPORT_SYMBOL_GPL(badblocks_show);
/** * badblocks_store() - sysfs access to bad-blocks list * @bb: the badblocks structure that holds all badblock information * @page: buffer received from sysfs * @len: length of data received from sysfs * @unack: weather to show unacknowledged badblocks * * Return: * Length of the buffer processed or -ve error. */ssize_t badblocks_store(struct badblocks *bb, const char *page, size_t len, int unack){ unsigned long long sector; int length; char newline;
switch (sscanf(page, "%llu %d%c", §or, &length, &newline)) { case 3: if (newline != '\n') return -EINVAL; fallthrough; case 2: if (length <= 0) return -EINVAL; break; default: return -EINVAL; }
if (!badblocks_set(bb, sector, length, !unack)) return -ENOSPC;
return len;}EXPORT_SYMBOL_GPL(badblocks_store);
static int __badblocks_init(struct device *dev, struct badblocks *bb, int enable){ bb->dev = dev; bb->count = 0; if (enable) bb->shift = 0; else bb->shift = -1; if (dev) bb->page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL); else bb->page = kzalloc(PAGE_SIZE, GFP_KERNEL); if (!bb->page) { bb->shift = -1; return -ENOMEM; } seqlock_init(&bb->lock);
return 0;}
/** * badblocks_init() - initialize the badblocks structure * @bb: the badblocks structure that holds all badblock information * @enable: weather to enable badblocks accounting * * Return: * 0: success * -ve errno: on error */int badblocks_init(struct badblocks *bb, int enable){ return __badblocks_init(NULL, bb, enable);}EXPORT_SYMBOL_GPL(badblocks_init);
int devm_init_badblocks(struct device *dev, struct badblocks *bb){ if (!bb) return -EINVAL; return __badblocks_init(dev, bb, 1);}EXPORT_SYMBOL_GPL(devm_init_badblocks);
/** * badblocks_exit() - free the badblocks structure * @bb: the badblocks structure that holds all badblock information */void badblocks_exit(struct badblocks *bb){ if (!bb) return; if (bb->dev) devm_kfree(bb->dev, bb->page); else kfree(bb->page); bb->page = NULL;}EXPORT_SYMBOL_GPL(badblocks_exit);