summaryrefslogtreecommitdiff
path: root/block/badblocks.c
diff options
context:
space:
mode:
Diffstat (limited to 'block/badblocks.c')
-rw-r--r--block/badblocks.c1550
1 files changed, 1550 insertions, 0 deletions
diff --git a/block/badblocks.c b/block/badblocks.c
new file mode 100644
index 000000000000..ece64e76fe8f
--- /dev/null
+++ b/block/badblocks.c
@@ -0,0 +1,1550 @@
+// 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", &sector, &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);
generated by cgit (git 2.34.1) at 2025-12-26 09:56:38 +0000