LCOV - code coverage report
Current view: top level - block - badblocks.c (source / functions) Hit Total Coverage
Test: combined.info Lines: 0 245 0.0 %
Date: 2022-04-01 14:35:51 Functions: 0 10 0.0 %
Branches: 0 175 0.0 %

           Branch data     Line data    Source code
       1                 :            : // SPDX-License-Identifier: GPL-2.0
       2                 :            : /*
       3                 :            :  * Bad block management
       4                 :            :  *
       5                 :            :  * - Heavily based on MD badblocks code from Neil Brown
       6                 :            :  *
       7                 :            :  * Copyright (c) 2015, Intel Corporation.
       8                 :            :  */
       9                 :            : 
      10                 :            : #include <linux/badblocks.h>
      11                 :            : #include <linux/seqlock.h>
      12                 :            : #include <linux/device.h>
      13                 :            : #include <linux/kernel.h>
      14                 :            : #include <linux/module.h>
      15                 :            : #include <linux/stddef.h>
      16                 :            : #include <linux/types.h>
      17                 :            : #include <linux/slab.h>
      18                 :            : 
      19                 :            : /**
      20                 :            :  * badblocks_check() - check a given range for bad sectors
      21                 :            :  * @bb:         the badblocks structure that holds all badblock information
      22                 :            :  * @s:          sector (start) at which to check for badblocks
      23                 :            :  * @sectors:    number of sectors to check for badblocks
      24                 :            :  * @first_bad:  pointer to store location of the first badblock
      25                 :            :  * @bad_sectors: pointer to store number of badblocks after @first_bad
      26                 :            :  *
      27                 :            :  * We can record which blocks on each device are 'bad' and so just
      28                 :            :  * fail those blocks, or that stripe, rather than the whole device.
      29                 :            :  * Entries in the bad-block table are 64bits wide.  This comprises:
      30                 :            :  * Length of bad-range, in sectors: 0-511 for lengths 1-512
      31                 :            :  * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes)
      32                 :            :  *  A 'shift' can be set so that larger blocks are tracked and
      33                 :            :  *  consequently larger devices can be covered.
      34                 :            :  * 'Acknowledged' flag - 1 bit. - the most significant bit.
      35                 :            :  *
      36                 :            :  * Locking of the bad-block table uses a seqlock so badblocks_check
      37                 :            :  * might need to retry if it is very unlucky.
      38                 :            :  * We will sometimes want to check for bad blocks in a bi_end_io function,
      39                 :            :  * so we use the write_seqlock_irq variant.
      40                 :            :  *
      41                 :            :  * When looking for a bad block we specify a range and want to
      42                 :            :  * know if any block in the range is bad.  So we binary-search
      43                 :            :  * to the last range that starts at-or-before the given endpoint,
      44                 :            :  * (or "before the sector after the target range")
      45                 :            :  * then see if it ends after the given start.
      46                 :            :  *
      47                 :            :  * Return:
      48                 :            :  *  0: there are no known bad blocks in the range
      49                 :            :  *  1: there are known bad block which are all acknowledged
      50                 :            :  * -1: there are bad blocks which have not yet been acknowledged in metadata.
      51                 :            :  * plus the start/length of the first bad section we overlap.
      52                 :            :  */
      53                 :          0 : int badblocks_check(struct badblocks *bb, sector_t s, int sectors,
      54                 :            :                         sector_t *first_bad, int *bad_sectors)
      55                 :            : {
      56                 :          0 :         int hi;
      57                 :          0 :         int lo;
      58                 :          0 :         u64 *p = bb->page;
      59                 :          0 :         int rv;
      60                 :          0 :         sector_t target = s + sectors;
      61                 :          0 :         unsigned seq;
      62                 :            : 
      63         [ #  # ]:          0 :         if (bb->shift > 0) {
      64                 :            :                 /* round the start down, and the end up */
      65                 :          0 :                 s >>= bb->shift;
      66                 :          0 :                 target += (1<<bb->shift) - 1;
      67                 :          0 :                 target >>= bb->shift;
      68                 :          0 :                 sectors = target - s;
      69                 :            :         }
      70                 :            :         /* 'target' is now the first block after the bad range */
      71                 :            : 
      72                 :          0 : retry:
      73                 :          0 :         seq = read_seqbegin(&bb->lock);
      74                 :          0 :         lo = 0;
      75                 :          0 :         rv = 0;
      76                 :          0 :         hi = bb->count;
      77                 :            : 
      78                 :            :         /* Binary search between lo and hi for 'target'
      79                 :            :          * i.e. for the last range that starts before 'target'
      80                 :            :          */
      81                 :            :         /* INVARIANT: ranges before 'lo' and at-or-after 'hi'
      82                 :            :          * are known not to be the last range before target.
      83                 :            :          * VARIANT: hi-lo is the number of possible
      84                 :            :          * ranges, and decreases until it reaches 1
      85                 :            :          */
      86         [ #  # ]:          0 :         while (hi - lo > 1) {
      87                 :          0 :                 int mid = (lo + hi) / 2;
      88                 :          0 :                 sector_t a = BB_OFFSET(p[mid]);
      89                 :            : 
      90         [ #  # ]:          0 :                 if (a < target)
      91                 :            :                         /* This could still be the one, earlier ranges
      92                 :            :                          * could not.
      93                 :            :                          */
      94                 :            :                         lo = mid;
      95                 :            :                 else
      96                 :            :                         /* This and later ranges are definitely out. */
      97                 :            :                         hi = mid;
      98                 :            :         }
      99                 :            :         /* 'lo' might be the last that started before target, but 'hi' isn't */
     100         [ #  # ]:          0 :         if (hi > lo) {
     101                 :            :                 /* need to check all range that end after 's' to see if
     102                 :            :                  * any are unacknowledged.
     103                 :            :                  */
     104         [ #  # ]:          0 :                 while (lo >= 0 &&
     105         [ #  # ]:          0 :                        BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
     106         [ #  # ]:          0 :                         if (BB_OFFSET(p[lo]) < target) {
     107                 :            :                                 /* starts before the end, and finishes after
     108                 :            :                                  * the start, so they must overlap
     109                 :            :                                  */
     110   [ #  #  #  # ]:          0 :                                 if (rv != -1 && BB_ACK(p[lo]))
     111                 :            :                                         rv = 1;
     112                 :            :                                 else
     113                 :          0 :                                         rv = -1;
     114                 :          0 :                                 *first_bad = BB_OFFSET(p[lo]);
     115                 :          0 :                                 *bad_sectors = BB_LEN(p[lo]);
     116                 :            :                         }
     117                 :          0 :                         lo--;
     118                 :            :                 }
     119                 :            :         }
     120                 :            : 
     121         [ #  # ]:          0 :         if (read_seqretry(&bb->lock, seq))
     122                 :          0 :                 goto retry;
     123                 :            : 
     124                 :          0 :         return rv;
     125                 :            : }
     126                 :            : EXPORT_SYMBOL_GPL(badblocks_check);
     127                 :            : 
     128                 :          0 : static void badblocks_update_acked(struct badblocks *bb)
     129                 :            : {
     130                 :          0 :         u64 *p = bb->page;
     131                 :          0 :         int i;
     132                 :          0 :         bool unacked = false;
     133                 :            : 
     134                 :          0 :         if (!bb->unacked_exist)
     135                 :            :                 return;
     136                 :            : 
     137   [ #  #  #  # ]:          0 :         for (i = 0; i < bb->count ; i++) {
     138   [ #  #  #  # ]:          0 :                 if (!BB_ACK(p[i])) {
     139                 :            :                         unacked = true;
     140                 :            :                         break;
     141                 :            :                 }
     142                 :            :         }
     143                 :            : 
     144   [ #  #  #  # ]:          0 :         if (!unacked)
     145                 :          0 :                 bb->unacked_exist = 0;
     146                 :            : }
     147                 :            : 
     148                 :            : /**
     149                 :            :  * badblocks_set() - Add a range of bad blocks to the table.
     150                 :            :  * @bb:         the badblocks structure that holds all badblock information
     151                 :            :  * @s:          first sector to mark as bad
     152                 :            :  * @sectors:    number of sectors to mark as bad
     153                 :            :  * @acknowledged: weather to mark the bad sectors as acknowledged
     154                 :            :  *
     155                 :            :  * This might extend the table, or might contract it if two adjacent ranges
     156                 :            :  * can be merged. We binary-search to find the 'insertion' point, then
     157                 :            :  * decide how best to handle it.
     158                 :            :  *
     159                 :            :  * Return:
     160                 :            :  *  0: success
     161                 :            :  *  1: failed to set badblocks (out of space)
     162                 :            :  */
     163                 :          0 : int badblocks_set(struct badblocks *bb, sector_t s, int sectors,
     164                 :            :                         int acknowledged)
     165                 :            : {
     166                 :          0 :         u64 *p;
     167                 :          0 :         int lo, hi;
     168                 :          0 :         int rv = 0;
     169                 :          0 :         unsigned long flags;
     170                 :            : 
     171         [ #  # ]:          0 :         if (bb->shift < 0)
     172                 :            :                 /* badblocks are disabled */
     173                 :            :                 return 1;
     174                 :            : 
     175         [ #  # ]:          0 :         if (bb->shift) {
     176                 :            :                 /* round the start down, and the end up */
     177                 :          0 :                 sector_t next = s + sectors;
     178                 :            : 
     179                 :          0 :                 s >>= bb->shift;
     180                 :          0 :                 next += (1<<bb->shift) - 1;
     181                 :          0 :                 next >>= bb->shift;
     182                 :          0 :                 sectors = next - s;
     183                 :            :         }
     184                 :            : 
     185                 :          0 :         write_seqlock_irqsave(&bb->lock, flags);
     186                 :            : 
     187                 :          0 :         p = bb->page;
     188                 :          0 :         lo = 0;
     189                 :          0 :         hi = bb->count;
     190                 :            :         /* Find the last range that starts at-or-before 's' */
     191         [ #  # ]:          0 :         while (hi - lo > 1) {
     192                 :          0 :                 int mid = (lo + hi) / 2;
     193                 :          0 :                 sector_t a = BB_OFFSET(p[mid]);
     194                 :            : 
     195         [ #  # ]:          0 :                 if (a <= s)
     196                 :            :                         lo = mid;
     197                 :            :                 else
     198                 :            :                         hi = mid;
     199                 :            :         }
     200   [ #  #  #  # ]:          0 :         if (hi > lo && BB_OFFSET(p[lo]) > s)
     201                 :          0 :                 hi = lo;
     202                 :            : 
     203         [ #  # ]:          0 :         if (hi > lo) {
     204                 :            :                 /* we found a range that might merge with the start
     205                 :            :                  * of our new range
     206                 :            :                  */
     207                 :          0 :                 sector_t a = BB_OFFSET(p[lo]);
     208                 :          0 :                 sector_t e = a + BB_LEN(p[lo]);
     209                 :          0 :                 int ack = BB_ACK(p[lo]);
     210                 :            : 
     211         [ #  # ]:          0 :                 if (e >= s) {
     212                 :            :                         /* Yes, we can merge with a previous range */
     213   [ #  #  #  # ]:          0 :                         if (s == a && s + sectors >= e)
     214                 :            :                                 /* new range covers old */
     215                 :            :                                 ack = acknowledged;
     216                 :            :                         else
     217                 :          0 :                                 ack = ack && acknowledged;
     218                 :            : 
     219                 :          0 :                         if (e < s + sectors)
     220                 :            :                                 e = s + sectors;
     221         [ #  # ]:          0 :                         if (e - a <= BB_MAX_LEN) {
     222         [ #  # ]:          0 :                                 p[lo] = BB_MAKE(a, e-a, ack);
     223                 :          0 :                                 s = e;
     224                 :            :                         } else {
     225                 :            :                                 /* does not all fit in one range,
     226                 :            :                                  * make p[lo] maximal
     227                 :            :                                  */
     228         [ #  # ]:          0 :                                 if (BB_LEN(p[lo]) != BB_MAX_LEN)
     229         [ #  # ]:          0 :                                         p[lo] = BB_MAKE(a, BB_MAX_LEN, ack);
     230                 :          0 :                                 s = a + BB_MAX_LEN;
     231                 :            :                         }
     232                 :          0 :                         sectors = e - s;
     233                 :            :                 }
     234                 :            :         }
     235   [ #  #  #  # ]:          0 :         if (sectors && hi < bb->count) {
     236                 :            :                 /* 'hi' points to the first range that starts after 's'.
     237                 :            :                  * Maybe we can merge with the start of that range
     238                 :            :                  */
     239                 :          0 :                 sector_t a = BB_OFFSET(p[hi]);
     240                 :          0 :                 sector_t e = a + BB_LEN(p[hi]);
     241                 :          0 :                 int ack = BB_ACK(p[hi]);
     242                 :            : 
     243         [ #  # ]:          0 :                 if (a <= s + sectors) {
     244                 :            :                         /* merging is possible */
     245         [ #  # ]:          0 :                         if (e <= s + sectors) {
     246                 :            :                                 /* full overlap */
     247                 :            :                                 e = s + sectors;
     248                 :            :                                 ack = acknowledged;
     249                 :            :                         } else
     250                 :          0 :                                 ack = ack && acknowledged;
     251                 :            : 
     252                 :          0 :                         a = s;
     253         [ #  # ]:          0 :                         if (e - a <= BB_MAX_LEN) {
     254         [ #  # ]:          0 :                                 p[hi] = BB_MAKE(a, e-a, ack);
     255                 :          0 :                                 s = e;
     256                 :            :                         } else {
     257         [ #  # ]:          0 :                                 p[hi] = BB_MAKE(a, BB_MAX_LEN, ack);
     258                 :          0 :                                 s = a + BB_MAX_LEN;
     259                 :            :                         }
     260                 :          0 :                         sectors = e - s;
     261                 :          0 :                         lo = hi;
     262                 :          0 :                         hi++;
     263                 :            :                 }
     264                 :            :         }
     265   [ #  #  #  # ]:          0 :         if (sectors == 0 && hi < bb->count) {
     266                 :            :                 /* we might be able to combine lo and hi */
     267                 :            :                 /* Note: 's' is at the end of 'lo' */
     268                 :          0 :                 sector_t a = BB_OFFSET(p[hi]);
     269                 :          0 :                 int lolen = BB_LEN(p[lo]);
     270                 :          0 :                 int hilen = BB_LEN(p[hi]);
     271                 :          0 :                 int newlen = lolen + hilen - (s - a);
     272                 :            : 
     273         [ #  # ]:          0 :                 if (s >= a && newlen < BB_MAX_LEN) {
     274                 :            :                         /* yes, we can combine them */
     275   [ #  #  #  # ]:          0 :                         int ack = BB_ACK(p[lo]) && BB_ACK(p[hi]);
     276                 :            : 
     277         [ #  # ]:          0 :                         p[lo] = BB_MAKE(BB_OFFSET(p[lo]), newlen, ack);
     278                 :          0 :                         memmove(p + hi, p + hi + 1,
     279                 :          0 :                                 (bb->count - hi - 1) * 8);
     280                 :          0 :                         bb->count--;
     281                 :            :                 }
     282                 :            :         }
     283         [ #  # ]:          0 :         while (sectors) {
     284                 :            :                 /* didn't merge (it all).
     285                 :            :                  * Need to add a range just before 'hi'
     286                 :            :                  */
     287         [ #  # ]:          0 :                 if (bb->count >= MAX_BADBLOCKS) {
     288                 :            :                         /* No room for more */
     289                 :            :                         rv = 1;
     290                 :            :                         break;
     291                 :            :                 } else {
     292                 :          0 :                         int this_sectors = sectors;
     293                 :            : 
     294                 :          0 :                         memmove(p + hi + 1, p + hi,
     295                 :          0 :                                 (bb->count - hi) * 8);
     296                 :          0 :                         bb->count++;
     297                 :            : 
     298                 :          0 :                         if (this_sectors > BB_MAX_LEN)
     299                 :            :                                 this_sectors = BB_MAX_LEN;
     300         [ #  # ]:          0 :                         p[hi] = BB_MAKE(s, this_sectors, acknowledged);
     301                 :          0 :                         sectors -= this_sectors;
     302                 :          0 :                         s += this_sectors;
     303                 :            :                 }
     304                 :            :         }
     305                 :            : 
     306                 :          0 :         bb->changed = 1;
     307         [ #  # ]:          0 :         if (!acknowledged)
     308                 :          0 :                 bb->unacked_exist = 1;
     309                 :            :         else
     310         [ #  # ]:          0 :                 badblocks_update_acked(bb);
     311                 :          0 :         write_sequnlock_irqrestore(&bb->lock, flags);
     312                 :            : 
     313                 :          0 :         return rv;
     314                 :            : }
     315                 :            : EXPORT_SYMBOL_GPL(badblocks_set);
     316                 :            : 
     317                 :            : /**
     318                 :            :  * badblocks_clear() - Remove a range of bad blocks to the table.
     319                 :            :  * @bb:         the badblocks structure that holds all badblock information
     320                 :            :  * @s:          first sector to mark as bad
     321                 :            :  * @sectors:    number of sectors to mark as bad
     322                 :            :  *
     323                 :            :  * This may involve extending the table if we spilt a region,
     324                 :            :  * but it must not fail.  So if the table becomes full, we just
     325                 :            :  * drop the remove request.
     326                 :            :  *
     327                 :            :  * Return:
     328                 :            :  *  0: success
     329                 :            :  *  1: failed to clear badblocks
     330                 :            :  */
     331                 :          0 : int badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
     332                 :            : {
     333                 :          0 :         u64 *p;
     334                 :          0 :         int lo, hi;
     335                 :          0 :         sector_t target = s + sectors;
     336                 :          0 :         int rv = 0;
     337                 :            : 
     338         [ #  # ]:          0 :         if (bb->shift > 0) {
     339                 :            :                 /* When clearing we round the start up and the end down.
     340                 :            :                  * This should not matter as the shift should align with
     341                 :            :                  * the block size and no rounding should ever be needed.
     342                 :            :                  * However it is better the think a block is bad when it
     343                 :            :                  * isn't than to think a block is not bad when it is.
     344                 :            :                  */
     345                 :          0 :                 s += (1<<bb->shift) - 1;
     346                 :          0 :                 s >>= bb->shift;
     347                 :          0 :                 target >>= bb->shift;
     348                 :          0 :                 sectors = target - s;
     349                 :            :         }
     350                 :            : 
     351                 :          0 :         write_seqlock_irq(&bb->lock);
     352                 :            : 
     353                 :          0 :         p = bb->page;
     354                 :          0 :         lo = 0;
     355                 :          0 :         hi = bb->count;
     356                 :            :         /* Find the last range that starts before 'target' */
     357         [ #  # ]:          0 :         while (hi - lo > 1) {
     358                 :          0 :                 int mid = (lo + hi) / 2;
     359                 :          0 :                 sector_t a = BB_OFFSET(p[mid]);
     360                 :            : 
     361         [ #  # ]:          0 :                 if (a < target)
     362                 :            :                         lo = mid;
     363                 :            :                 else
     364                 :            :                         hi = mid;
     365                 :            :         }
     366         [ #  # ]:          0 :         if (hi > lo) {
     367                 :            :                 /* p[lo] is the last range that could overlap the
     368                 :            :                  * current range.  Earlier ranges could also overlap,
     369                 :            :                  * but only this one can overlap the end of the range.
     370                 :            :                  */
     371   [ #  #  #  # ]:          0 :                 if ((BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > target) &&
     372                 :            :                     (BB_OFFSET(p[lo]) < target)) {
     373                 :            :                         /* Partial overlap, leave the tail of this range */
     374                 :          0 :                         int ack = BB_ACK(p[lo]);
     375                 :          0 :                         sector_t a = BB_OFFSET(p[lo]);
     376                 :          0 :                         sector_t end = a + BB_LEN(p[lo]);
     377                 :            : 
     378         [ #  # ]:          0 :                         if (a < s) {
     379                 :            :                                 /* we need to split this range */
     380         [ #  # ]:          0 :                                 if (bb->count >= MAX_BADBLOCKS) {
     381                 :          0 :                                         rv = -ENOSPC;
     382                 :          0 :                                         goto out;
     383                 :            :                                 }
     384                 :          0 :                                 memmove(p+lo+1, p+lo, (bb->count - lo) * 8);
     385                 :          0 :                                 bb->count++;
     386         [ #  # ]:          0 :                                 p[lo] = BB_MAKE(a, s-a, ack);
     387                 :          0 :                                 lo++;
     388                 :            :                         }
     389         [ #  # ]:          0 :                         p[lo] = BB_MAKE(target, end - target, ack);
     390                 :            :                         /* there is no longer an overlap */
     391                 :          0 :                         hi = lo;
     392                 :          0 :                         lo--;
     393                 :            :                 }
     394         [ #  # ]:          0 :                 while (lo >= 0 &&
     395   [ #  #  #  # ]:          0 :                        (BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) &&
     396                 :            :                        (BB_OFFSET(p[lo]) < target)) {
     397                 :            :                         /* This range does overlap */
     398         [ #  # ]:          0 :                         if (BB_OFFSET(p[lo]) < s) {
     399                 :            :                                 /* Keep the early parts of this range. */
     400                 :          0 :                                 int ack = BB_ACK(p[lo]);
     401                 :          0 :                                 sector_t start = BB_OFFSET(p[lo]);
     402                 :            : 
     403         [ #  # ]:          0 :                                 p[lo] = BB_MAKE(start, s - start, ack);
     404                 :            :                                 /* now low doesn't overlap, so.. */
     405                 :          0 :                                 break;
     406                 :            :                         }
     407                 :          0 :                         lo--;
     408                 :            :                 }
     409                 :            :                 /* 'lo' is strictly before, 'hi' is strictly after,
     410                 :            :                  * anything between needs to be discarded
     411                 :            :                  */
     412         [ #  # ]:          0 :                 if (hi - lo > 1) {
     413                 :          0 :                         memmove(p+lo+1, p+hi, (bb->count - hi) * 8);
     414                 :          0 :                         bb->count -= (hi - lo - 1);
     415                 :            :                 }
     416                 :            :         }
     417                 :            : 
     418         [ #  # ]:          0 :         badblocks_update_acked(bb);
     419                 :          0 :         bb->changed = 1;
     420                 :          0 : out:
     421                 :          0 :         write_sequnlock_irq(&bb->lock);
     422                 :          0 :         return rv;
     423                 :            : }
     424                 :            : EXPORT_SYMBOL_GPL(badblocks_clear);
     425                 :            : 
     426                 :            : /**
     427                 :            :  * ack_all_badblocks() - Acknowledge all bad blocks in a list.
     428                 :            :  * @bb:         the badblocks structure that holds all badblock information
     429                 :            :  *
     430                 :            :  * This only succeeds if ->changed is clear.  It is used by
     431                 :            :  * in-kernel metadata updates
     432                 :            :  */
     433                 :          0 : void ack_all_badblocks(struct badblocks *bb)
     434                 :            : {
     435   [ #  #  #  # ]:          0 :         if (bb->page == NULL || bb->changed)
     436                 :            :                 /* no point even trying */
     437                 :            :                 return;
     438                 :          0 :         write_seqlock_irq(&bb->lock);
     439                 :            : 
     440   [ #  #  #  # ]:          0 :         if (bb->changed == 0 && bb->unacked_exist) {
     441                 :          0 :                 u64 *p = bb->page;
     442                 :          0 :                 int i;
     443                 :            : 
     444         [ #  # ]:          0 :                 for (i = 0; i < bb->count ; i++) {
     445         [ #  # ]:          0 :                         if (!BB_ACK(p[i])) {
     446                 :          0 :                                 sector_t start = BB_OFFSET(p[i]);
     447                 :          0 :                                 int len = BB_LEN(p[i]);
     448                 :            : 
     449                 :          0 :                                 p[i] = BB_MAKE(start, len, 1);
     450                 :            :                         }
     451                 :            :                 }
     452                 :          0 :                 bb->unacked_exist = 0;
     453                 :            :         }
     454                 :          0 :         write_sequnlock_irq(&bb->lock);
     455                 :            : }
     456                 :            : EXPORT_SYMBOL_GPL(ack_all_badblocks);
     457                 :            : 
     458                 :            : /**
     459                 :            :  * badblocks_show() - sysfs access to bad-blocks list
     460                 :            :  * @bb:         the badblocks structure that holds all badblock information
     461                 :            :  * @page:       buffer received from sysfs
     462                 :            :  * @unack:      weather to show unacknowledged badblocks
     463                 :            :  *
     464                 :            :  * Return:
     465                 :            :  *  Length of returned data
     466                 :            :  */
     467                 :          0 : ssize_t badblocks_show(struct badblocks *bb, char *page, int unack)
     468                 :            : {
     469                 :          0 :         size_t len;
     470                 :          0 :         int i;
     471                 :          0 :         u64 *p = bb->page;
     472                 :          0 :         unsigned seq;
     473                 :            : 
     474         [ #  # ]:          0 :         if (bb->shift < 0)
     475                 :            :                 return 0;
     476                 :            : 
     477                 :          0 : retry:
     478                 :          0 :         seq = read_seqbegin(&bb->lock);
     479                 :            : 
     480                 :          0 :         len = 0;
     481                 :          0 :         i = 0;
     482                 :            : 
     483   [ #  #  #  # ]:          0 :         while (len < PAGE_SIZE && i < bb->count) {
     484                 :          0 :                 sector_t s = BB_OFFSET(p[i]);
     485                 :          0 :                 unsigned int length = BB_LEN(p[i]);
     486                 :          0 :                 int ack = BB_ACK(p[i]);
     487                 :            : 
     488                 :          0 :                 i++;
     489                 :            : 
     490         [ #  # ]:          0 :                 if (unack && ack)
     491                 :          0 :                         continue;
     492                 :            : 
     493                 :          0 :                 len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n",
     494                 :            :                                 (unsigned long long)s << bb->shift,
     495                 :          0 :                                 length << bb->shift);
     496                 :            :         }
     497         [ #  # ]:          0 :         if (unack && len == 0)
     498                 :          0 :                 bb->unacked_exist = 0;
     499                 :            : 
     500         [ #  # ]:          0 :         if (read_seqretry(&bb->lock, seq))
     501                 :          0 :                 goto retry;
     502                 :            : 
     503                 :          0 :         return len;
     504                 :            : }
     505                 :            : EXPORT_SYMBOL_GPL(badblocks_show);
     506                 :            : 
     507                 :            : /**
     508                 :            :  * badblocks_store() - sysfs access to bad-blocks list
     509                 :            :  * @bb:         the badblocks structure that holds all badblock information
     510                 :            :  * @page:       buffer received from sysfs
     511                 :            :  * @len:        length of data received from sysfs
     512                 :            :  * @unack:      weather to show unacknowledged badblocks
     513                 :            :  *
     514                 :            :  * Return:
     515                 :            :  *  Length of the buffer processed or -ve error.
     516                 :            :  */
     517                 :          0 : ssize_t badblocks_store(struct badblocks *bb, const char *page, size_t len,
     518                 :            :                         int unack)
     519                 :            : {
     520                 :          0 :         unsigned long long sector;
     521                 :          0 :         int length;
     522                 :          0 :         char newline;
     523                 :            : 
     524      [ #  #  # ]:          0 :         switch (sscanf(page, "%llu %d%c", &sector, &length, &newline)) {
     525                 :          0 :         case 3:
     526         [ #  # ]:          0 :                 if (newline != '\n')
     527                 :            :                         return -EINVAL;
     528                 :            :                 /* fall through */
     529                 :            :         case 2:
     530         [ #  # ]:          0 :                 if (length <= 0)
     531                 :            :                         return -EINVAL;
     532                 :          0 :                 break;
     533                 :            :         default:
     534                 :            :                 return -EINVAL;
     535                 :            :         }
     536                 :            : 
     537         [ #  # ]:          0 :         if (badblocks_set(bb, sector, length, !unack))
     538                 :            :                 return -ENOSPC;
     539                 :            :         else
     540                 :          0 :                 return len;
     541                 :            : }
     542                 :            : EXPORT_SYMBOL_GPL(badblocks_store);
     543                 :            : 
     544                 :          0 : static int __badblocks_init(struct device *dev, struct badblocks *bb,
     545                 :            :                 int enable)
     546                 :            : {
     547                 :          0 :         bb->dev = dev;
     548                 :          0 :         bb->count = 0;
     549         [ #  # ]:          0 :         if (enable)
     550                 :          0 :                 bb->shift = 0;
     551                 :            :         else
     552                 :          0 :                 bb->shift = -1;
     553         [ #  # ]:          0 :         if (dev)
     554                 :          0 :                 bb->page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL);
     555                 :            :         else
     556                 :          0 :                 bb->page = kzalloc(PAGE_SIZE, GFP_KERNEL);
     557         [ #  # ]:          0 :         if (!bb->page) {
     558                 :          0 :                 bb->shift = -1;
     559                 :          0 :                 return -ENOMEM;
     560                 :            :         }
     561                 :          0 :         seqlock_init(&bb->lock);
     562                 :            : 
     563                 :          0 :         return 0;
     564                 :            : }
     565                 :            : 
     566                 :            : /**
     567                 :            :  * badblocks_init() - initialize the badblocks structure
     568                 :            :  * @bb:         the badblocks structure that holds all badblock information
     569                 :            :  * @enable:     weather to enable badblocks accounting
     570                 :            :  *
     571                 :            :  * Return:
     572                 :            :  *  0: success
     573                 :            :  *  -ve errno: on error
     574                 :            :  */
     575                 :          0 : int badblocks_init(struct badblocks *bb, int enable)
     576                 :            : {
     577                 :          0 :         return __badblocks_init(NULL, bb, enable);
     578                 :            : }
     579                 :            : EXPORT_SYMBOL_GPL(badblocks_init);
     580                 :            : 
     581                 :          0 : int devm_init_badblocks(struct device *dev, struct badblocks *bb)
     582                 :            : {
     583         [ #  # ]:          0 :         if (!bb)
     584                 :            :                 return -EINVAL;
     585                 :          0 :         return __badblocks_init(dev, bb, 1);
     586                 :            : }
     587                 :            : EXPORT_SYMBOL_GPL(devm_init_badblocks);
     588                 :            : 
     589                 :            : /**
     590                 :            :  * badblocks_exit() - free the badblocks structure
     591                 :            :  * @bb:         the badblocks structure that holds all badblock information
     592                 :            :  */
     593                 :          0 : void badblocks_exit(struct badblocks *bb)
     594                 :            : {
     595         [ #  # ]:          0 :         if (!bb)
     596                 :            :                 return;
     597         [ #  # ]:          0 :         if (bb->dev)
     598                 :          0 :                 devm_kfree(bb->dev, bb->page);
     599                 :            :         else
     600                 :          0 :                 kfree(bb->page);
     601                 :          0 :         bb->page = NULL;
     602                 :            : }
     603                 :            : EXPORT_SYMBOL_GPL(badblocks_exit);

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