diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/badblocks.c | 386 |
1 files changed, 386 insertions, 0 deletions
diff --git a/block/badblocks.c b/block/badblocks.c index 3afb550c0f7b78..7e7f9f14bb1d35 100644 --- a/block/badblocks.c +++ b/block/badblocks.c @@ -16,6 +16,392 @@ #include <linux/types.h> #include <linux/slab.h> +/* + * 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 backward merged + * with the bad range (from the bad table) index by 'behind'. + */ +static bool can_merge_behind(struct badblocks *bb, + struct badblocks_context *bad, int behind) +{ + sector_t sectors = bad->len; + sector_t s = bad->start; + u64 *p = bb->page; + + if ((s < BB_OFFSET(p[behind])) && + ((s + sectors) >= BB_OFFSET(p[behind])) && + ((BB_END(p[behind]) - s) <= BB_MAX_LEN) && + BB_ACK(p[behind]) == bad->ack) + return true; + return false; +} + +/* + * Do backward merge for range indicated by 'bad' and the bad range + * (from the bad table) indexed by 'behind'. The return value is merged + * sectors from bad->len. + */ +static int behind_merge(struct badblocks *bb, struct badblocks_context *bad, + int behind) +{ + sector_t sectors = bad->len; + sector_t s = bad->start; + u64 *p = bb->page; + int merged = 0; + + WARN_ON(s >= BB_OFFSET(p[behind])); + WARN_ON((s + sectors) < BB_OFFSET(p[behind])); + + if (s < BB_OFFSET(p[behind])) { + merged = BB_OFFSET(p[behind]) - s; + p[behind] = BB_MAKE(s, BB_LEN(p[behind]) + merged, bad->ack); + + WARN_ON((BB_LEN(p[behind]) + merged) >= BB_MAX_LEN); + } + + return merged; +} + +/* + * 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; +} + /** * badblocks_check() - check a given range for bad sectors * @bb: the badblocks structure that holds all badblock information |