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-rw-r--r--block/badblocks.c386
1 files changed, 386 insertions, 0 deletions
diff --git a/block/badblocks.c b/block/badblocks.c
index 3afb550c0f7b..7e7f9f14bb1d 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