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db448eb686
linux/block/badblocks.c
Coly Li db448eb686 badblocks: improve badblocks_clear() for multiple ranges handling 
With the fundamental ideas and helper routines from badblocks_set()
improvement, clearing bad block for multiple ranges is much simpler.

With a similar idea from badblocks_set() improvement, this patch
simplifies bad block range clearing into 5 situations. No matter how
complicated the clearing condition is, we just look at the head part
of clearing range with relative already set bad block range from the
bad block table. The rested part will be handled in next run of the
while-loop.

Based on existing helpers added from badblocks_set(), this patch adds
two more helpers,
- front_clear()
  Clear the bad block range from bad block table which is front
  overlapped with the clearing range.
- front_splitting_clear()
  Handle the condition that the clearing range hits middle of an
  already set bad block range from bad block table.

Similar as badblocks_set(), the first part of clearing range is handled
with relative bad block range which is find by prev_badblocks(). In most
cases a valid hint is provided to prev_badblocks() to avoid unnecessary
bad block table iteration.

This patch also explains the detail algorithm code comments at beginning
of badblocks.c, including which five simplified situations are
categrized and how all the bad block range clearing conditions are
handled by these five situations.

Again, in order to make the code review easier and avoid the code
changes mixed together, this patch does not modify badblock_clear() and
implement another routine called _badblock_clear() for the improvement.
Later patch will delete current code of badblock_clear() and make it as
a wrapper to _badblock_clear(), so the code change can be much clear for
review.

Signed-off-by: Coly Li <colyli@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Geliang Tang <geliang.tang@suse.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: NeilBrown <neilb@suse.de>
Cc: Vishal L Verma <vishal.l.verma@intel.com>
Cc: Xiao Ni <xni@redhat.com>
Reviewed-by: Xiao Ni <xni@redhat.com>
Acked-by: Geliang Tang <geliang.tang@suse.com>
Link: https://lore.kernel.org/r/20230811170513.2300-5-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-09-26 00:44:33 -06:00

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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 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;
}
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;
}
/* Do exact work to set bad block range into the bad block table */
static int _badblocks_set(struct badblocks *bb, sector_t s, int sectors,
int acknowledged)
{
int retried = 0, space_desired = 0;
int orig_len, len = 0, added = 0;
struct badblocks_context bad;
int prev = -1, hint = -1;
sector_t orig_start;
unsigned long flags;
int rv = 0;
u64 *p;
if (bb->shift < 0)
/* badblocks are disabled */
return 1;
if (sectors == 0)
/* Invalid sectors number */
return 1;
if (bb->shift) {
/* round the start down, and the end up */
sector_t next = s + sectors;
rounddown(s, bb->shift);
roundup(next, bb->shift);
sectors = next - s;
}
write_seqlock_irqsave(&bb->lock, flags);
orig_start = s;
orig_len = sectors;
bad.ack = acknowledged;
p = bb->page;
re_insert:
bad.start = s;
bad.len = sectors;
len = 0;
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) {
if (!badblocks_full(bb)) {
/* 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 = 0;
goto update_sectors;
}
/* No sapce, try to merge */
if (overlap_behind(bb, &bad, 0)) {
if (can_merge_behind(bb, &bad, 0)) {
len = behind_merge(bb, &bad, 0);
added++;
} else {
len = BB_OFFSET(p[0]) - s;
space_desired = 1;
}
hint = 0;
goto update_sectors;
}
/* no table space and give up */
goto out;
}
/* 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 (overlap_front(bb, prev, &bad)) {
if (can_merge_front(bb, prev, &bad)) {
len = front_merge(bb, prev, &bad);
added++;
} else {
int extra = 0;
if (!can_front_overwrite(bb, prev, &bad, &extra)) {
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;
}
if (can_merge_front(bb, prev, &bad)) {
len = front_merge(bb, prev, &bad);
added++;
hint = prev;
goto update_sectors;
}
/* if no space in table, still try to merge in the covered range */
if (badblocks_full(bb)) {
/* skip the cannot-merge range */
if (((prev + 1) < bb->count) &&
overlap_behind(bb, &bad, prev + 1) &&
((s + sectors) >= BB_END(p[prev + 1]))) {
len = BB_END(p[prev + 1]) - s;
hint = prev + 1;
goto update_sectors;
}
/* no retry any more */
len = sectors;
space_desired = 1;
hint = -1;
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 + 1;
update_sectors:
s += len;
sectors -= len;
if (sectors > 0)
goto re_insert;
WARN_ON(sectors < 0);
/*
* Check whether the following already set range can be
* merged. (prev < 0) condition is not handled here,
* because it's already complicated enough.
*/
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--;
}
if (space_desired && !badblocks_full(bb)) {
s = orig_start;
sectors = orig_len;
space_desired = 0;
if (retried++ < 3)
goto re_insert;
}
out:
if (added) {
set_changed(bb);
if (!acknowledged)
bb->unacked_exist = 1;
else
badblocks_update_acked(bb);
}
write_sequnlock_irqrestore(&bb->lock, flags);
if (!added)
rv = 1;
return rv;
}
/*
* 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 int _badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
{
struct badblocks_context bad;
int prev = -1, hint = -1;
int len = 0, cleared = 0;
int rv = 0;
u64 *p;
if (bb->shift < 0)
/* badblocks are disabled */
return 1;
if (sectors == 0)
/* Invalid sectors number */
return 1;
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, bb->shift);
rounddown(target, 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;
WARN_ON(sectors < 0);
if (cleared) {
badblocks_update_acked(bb);
set_changed(bb);
}
write_sequnlock_irq(&bb->lock);
if (!cleared)
rv = 1;
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, int sectors,
sector_t *first_bad, int *bad_sectors)
{
int hi;
int lo;
u64 *p = bb->page;
int rv;
sector_t target = s + sectors;
unsigned seq;
if (bb->shift > 0) {
/* round the start down, and the end up */
s >>= bb->shift;
target += (1<<bb->shift) - 1;
target >>= bb->shift;
}
/* 'target' is now the first block after the bad range */
retry:
seq = read_seqbegin(&bb->lock);
lo = 0;
rv = 0;
hi = bb->count;
/* Binary search between lo and hi for 'target'
* i.e. for the last range that starts before 'target'
*/
/* INVARIANT: ranges before 'lo' and at-or-after 'hi'
* are known not to be the last range before target.
* VARIANT: hi-lo is the number of possible
* ranges, and decreases until it reaches 1
*/
while (hi - lo > 1) {
int mid = (lo + hi) / 2;
sector_t a = BB_OFFSET(p[mid]);
if (a < target)
/* This could still be the one, earlier ranges
* could not.
*/
lo = mid;
else
/* This and later ranges are definitely out. */
hi = mid;
}
/* 'lo' might be the last that started before target, but 'hi' isn't */
if (hi > lo) {
/* need to check all range that end after 's' to see if
* any are unacknowledged.
*/
while (lo >= 0 &&
BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
if (BB_OFFSET(p[lo]) < target) {
/* starts before the end, and finishes after
* the start, so they must overlap
*/
if (rv != -1 && BB_ACK(p[lo]))
rv = 1;
else
rv = -1;
*first_bad = BB_OFFSET(p[lo]);
*bad_sectors = BB_LEN(p[lo]);
}
lo--;
}
}
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:
* 0: success
* 1: failed to set badblocks (out of space)
*/
int badblocks_set(struct badblocks *bb, sector_t s, int sectors,
int acknowledged)
{
u64 *p;
int lo, hi;
int rv = 0;
unsigned long flags;
if (bb->shift < 0)
/* badblocks are disabled */
return 1;
if (bb->shift) {
/* round the start down, and the end up */
sector_t next = s + sectors;
s >>= bb->shift;
next += (1<<bb->shift) - 1;
next >>= bb->shift;
sectors = next - s;
}
write_seqlock_irqsave(&bb->lock, flags);
p = bb->page;
lo = 0;
hi = bb->count;
/* Find the last range that starts at-or-before 's' */
while (hi - lo > 1) {
int mid = (lo + hi) / 2;
sector_t a = BB_OFFSET(p[mid]);
if (a <= s)
lo = mid;
else
hi = mid;
}
if (hi > lo && BB_OFFSET(p[lo]) > s)
hi = lo;
if (hi > lo) {
/* we found a range that might merge with the start
* of our new range
*/
sector_t a = BB_OFFSET(p[lo]);
sector_t e = a + BB_LEN(p[lo]);
int ack = BB_ACK(p[lo]);
if (e >= s) {
/* Yes, we can merge with a previous range */
if (s == a && s + sectors >= e)
/* new range covers old */
ack = acknowledged;
else
ack = ack && acknowledged;
if (e < s + sectors)
e = s + sectors;
if (e - a <= BB_MAX_LEN) {
p[lo] = BB_MAKE(a, e-a, ack);
s = e;
} else {
/* does not all fit in one range,
* make p[lo] maximal
*/
if (BB_LEN(p[lo]) != BB_MAX_LEN)
p[lo] = BB_MAKE(a, BB_MAX_LEN, ack);
s = a + BB_MAX_LEN;
}
sectors = e - s;
}
}
if (sectors && hi < bb->count) {
/* 'hi' points to the first range that starts after 's'.
* Maybe we can merge with the start of that range
*/
sector_t a = BB_OFFSET(p[hi]);
sector_t e = a + BB_LEN(p[hi]);
int ack = BB_ACK(p[hi]);
if (a <= s + sectors) {
/* merging is possible */
if (e <= s + sectors) {
/* full overlap */
e = s + sectors;
ack = acknowledged;
} else
ack = ack && acknowledged;
a = s;
if (e - a <= BB_MAX_LEN) {
p[hi] = BB_MAKE(a, e-a, ack);
s = e;
} else {
p[hi] = BB_MAKE(a, BB_MAX_LEN, ack);
s = a + BB_MAX_LEN;
}
sectors = e - s;
lo = hi;
hi++;
}
}
if (sectors == 0 && hi < bb->count) {
/* we might be able to combine lo and hi */
/* Note: 's' is at the end of 'lo' */
sector_t a = BB_OFFSET(p[hi]);
int lolen = BB_LEN(p[lo]);
int hilen = BB_LEN(p[hi]);
int newlen = lolen + hilen - (s - a);
if (s >= a && newlen < BB_MAX_LEN) {
/* yes, we can combine them */
int ack = BB_ACK(p[lo]) && BB_ACK(p[hi]);
p[lo] = BB_MAKE(BB_OFFSET(p[lo]), newlen, ack);
memmove(p + hi, p + hi + 1,
(bb->count - hi - 1) * 8);
bb->count--;
}
}
while (sectors) {
/* didn't merge (it all).
* Need to add a range just before 'hi'
*/
if (bb->count >= MAX_BADBLOCKS) {
/* No room for more */
rv = 1;
break;
} else {
int this_sectors = sectors;
memmove(p + hi + 1, p + hi,
(bb->count - hi) * 8);
bb->count++;
if (this_sectors > BB_MAX_LEN)
this_sectors = BB_MAX_LEN;
p[hi] = BB_MAKE(s, this_sectors, acknowledged);
sectors -= this_sectors;
s += this_sectors;
}
}
bb->changed = 1;
if (!acknowledged)
bb->unacked_exist = 1;
else
badblocks_update_acked(bb);
write_sequnlock_irqrestore(&bb->lock, flags);
return rv;
}
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:
* 0: success
* 1: failed to clear badblocks
*/
int badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
{
u64 *p;
int lo, hi;
sector_t target = s + sectors;
int rv = 0;
if (bb->shift > 0) {
/* 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.
*/
s += (1<<bb->shift) - 1;
s >>= bb->shift;
target >>= bb->shift;
}
write_seqlock_irq(&bb->lock);
p = bb->page;
lo = 0;
hi = bb->count;
/* Find the last range that starts before 'target' */
while (hi - lo > 1) {
int mid = (lo + hi) / 2;
sector_t a = BB_OFFSET(p[mid]);
if (a < target)
lo = mid;
else
hi = mid;
}
if (hi > lo) {
/* p[lo] is the last range that could overlap the
* current range. Earlier ranges could also overlap,
* but only this one can overlap the end of the range.
*/
if ((BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > target) &&
(BB_OFFSET(p[lo]) < target)) {
/* Partial overlap, leave the tail of this range */
int ack = BB_ACK(p[lo]);
sector_t a = BB_OFFSET(p[lo]);
sector_t end = a + BB_LEN(p[lo]);
if (a < s) {
/* we need to split this range */
if (bb->count >= MAX_BADBLOCKS) {
rv = -ENOSPC;
goto out;
}
memmove(p+lo+1, p+lo, (bb->count - lo) * 8);
bb->count++;
p[lo] = BB_MAKE(a, s-a, ack);
lo++;
}
p[lo] = BB_MAKE(target, end - target, ack);
/* there is no longer an overlap */
hi = lo;
lo--;
}
while (lo >= 0 &&
(BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) &&
(BB_OFFSET(p[lo]) < target)) {
/* This range does overlap */
if (BB_OFFSET(p[lo]) < s) {
/* Keep the early parts of this range. */
int ack = BB_ACK(p[lo]);
sector_t start = BB_OFFSET(p[lo]);
p[lo] = BB_MAKE(start, s - start, ack);
/* now low doesn't overlap, so.. */
break;
}
lo--;
}
/* 'lo' is strictly before, 'hi' is strictly after,
* anything between needs to be discarded
*/
if (hi - lo > 1) {
memmove(p+lo+1, p+hi, (bb->count - hi) * 8);
bb->count -= (hi - lo - 1);
}
}
badblocks_update_acked(bb);
bb->changed = 1;
out:
write_sequnlock_irq(&bb->lock);
return rv;
}
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);
}
}
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;
else
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);
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