drivers/mtd/ubi/fastmap-wl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2012 Linutronix GmbH
   4  * Copyright (c) 2014 sigma star gmbh
   5  * Author: Richard Weinberger <[email protected]>
   6  */
   7
   8 /**
   9  * update_fastmap_work_fn - calls ubi_update_fastmap from a work queue
  10  * @wrk: the work description object
  11  */
  12 static void update_fastmap_work_fn(struct work_struct *wrk)
  13 {
  14         struct ubi_device *ubi = container_of(wrk, struct ubi_device, fm_work);
  15
  16         ubi_update_fastmap(ubi);
  17         spin_lock(&ubi->wl_lock);
  18         ubi->fm_work_scheduled = 0;
  19         spin_unlock(&ubi->wl_lock);
  20 }
  21
  22 /**
  23  * find_anchor_wl_entry - find wear-leveling entry to used as anchor PEB.
  24  * @root: the RB-tree where to look for
  25  */
  26 static struct ubi_wl_entry *find_anchor_wl_entry(struct rb_root *root)
  27 {
  28         struct rb_node *p;
  29         struct ubi_wl_entry *e, *victim = NULL;
  30         int max_ec = UBI_MAX_ERASECOUNTER;
  31
  32         ubi_rb_for_each_entry(p, e, root, u.rb) {
  33                 if (e->pnum < UBI_FM_MAX_START && e->ec < max_ec) {
  34                         victim = e;
  35                         max_ec = e->ec;
  36                 }
  37         }
  38
  39         return victim;
  40 }
  41
  42 static inline void return_unused_peb(struct ubi_device *ubi,
  43                                      struct ubi_wl_entry *e)
  44 {
  45         wl_tree_add(e, &ubi->free);
  46         ubi->free_count++;
  47 }
  48
  49 /**
  50  * return_unused_pool_pebs - returns unused PEB to the free tree.
  51  * @ubi: UBI device description object
  52  * @pool: fastmap pool description object
  53  */
  54 static void return_unused_pool_pebs(struct ubi_device *ubi,
  55                                     struct ubi_fm_pool *pool)
  56 {
  57         int i;
  58         struct ubi_wl_entry *e;
  59
  60         for (i = pool->used; i < pool->size; i++) {
  61                 e = ubi->lookuptbl[pool->pebs[i]];
  62                 return_unused_peb(ubi, e);
  63         }
  64 }
  65
  66 /**
  67  * ubi_wl_get_fm_peb - find a physical erase block with a given maximal number.
  68  * @ubi: UBI device description object
  69  * @anchor: This PEB will be used as anchor PEB by fastmap
  70  *
  71  * The function returns a physical erase block with a given maximal number
  72  * and removes it from the wl subsystem.
  73  * Must be called with wl_lock held!
  74  */
  75 struct ubi_wl_entry *ubi_wl_get_fm_peb(struct ubi_device *ubi, int anchor)
  76 {
  77         struct ubi_wl_entry *e = NULL;
  78
  79         if (!ubi->free.rb_node || (ubi->free_count - ubi->beb_rsvd_pebs < 1))
  80                 goto out;
  81
  82         if (anchor)
  83                 e = find_anchor_wl_entry(&ubi->free);
  84         else
  85                 e = find_mean_wl_entry(ubi, &ubi->free);
  86
  87         if (!e)
  88                 goto out;
  89
  90         self_check_in_wl_tree(ubi, e, &ubi->free);
  91
  92         /* remove it from the free list,
  93          * the wl subsystem does no longer know this erase block */
  94         rb_erase(&e->u.rb, &ubi->free);
  95         ubi->free_count--;
  96 out:
  97         return e;
  98 }
  99
 100 /**
 101  * ubi_refill_pools - refills all fastmap PEB pools.
 102  * @ubi: UBI device description object
 103  */
 104 void ubi_refill_pools(struct ubi_device *ubi)
 105 {
 106         struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
 107         struct ubi_fm_pool *pool = &ubi->fm_pool;
 108         struct ubi_wl_entry *e;
 109         int enough;
 110
 111         spin_lock(&ubi->wl_lock);
 112
 113         return_unused_pool_pebs(ubi, wl_pool);
 114         return_unused_pool_pebs(ubi, pool);
 115
 116         wl_pool->size = 0;
 117         pool->size = 0;
 118
 119         for (;;) {
 120                 enough = 0;
 121                 if (pool->size < pool->max_size) {
 122                         if (!ubi->free.rb_node)
 123                                 break;
 124
 125                         e = wl_get_wle(ubi);
 126                         if (!e)
 127                                 break;
 128
 129                         pool->pebs[pool->size] = e->pnum;
 130                         pool->size++;
 131                 } else
 132                         enough++;
 133
 134                 if (wl_pool->size < wl_pool->max_size) {
 135                         if (!ubi->free.rb_node ||
 136                            (ubi->free_count - ubi->beb_rsvd_pebs < 5))
 137                                 break;
 138
 139                         e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
 140                         self_check_in_wl_tree(ubi, e, &ubi->free);
 141                         rb_erase(&e->u.rb, &ubi->free);
 142                         ubi->free_count--;
 143
 144                         wl_pool->pebs[wl_pool->size] = e->pnum;
 145                         wl_pool->size++;
 146                 } else
 147                         enough++;
 148
 149                 if (enough == 2)
 150                         break;
 151         }
 152
 153         wl_pool->used = 0;
 154         pool->used = 0;
 155
 156         spin_unlock(&ubi->wl_lock);
 157 }
 158
 159 /**
 160  * produce_free_peb - produce a free physical eraseblock.
 161  * @ubi: UBI device description object
 162  *
 163  * This function tries to make a free PEB by means of synchronous execution of
 164  * pending works. This may be needed if, for example the background thread is
 165  * disabled. Returns zero in case of success and a negative error code in case
 166  * of failure.
 167  */
 168 static int produce_free_peb(struct ubi_device *ubi)
 169 {
 170         int err;
 171
 172         while (!ubi->free.rb_node && ubi->works_count) {
 173                 dbg_wl("do one work synchronously");
 174                 err = do_work(ubi);
 175
 176                 if (err)
 177                         return err;
 178         }
 179
 180         return 0;
 181 }
 182
 183 /**
 184  * ubi_wl_get_peb - get a physical eraseblock.
 185  * @ubi: UBI device description object
 186  *
 187  * This function returns a physical eraseblock in case of success and a
 188  * negative error code in case of failure.
 189  * Returns with ubi->fm_eba_sem held in read mode!
 190  */
 191 int ubi_wl_get_peb(struct ubi_device *ubi)
 192 {
 193         int ret, attempts = 0;
 194         struct ubi_fm_pool *pool = &ubi->fm_pool;
 195         struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
 196
 197 again:
 198         down_read(&ubi->fm_eba_sem);
 199         spin_lock(&ubi->wl_lock);
 200
 201         /* We check here also for the WL pool because at this point we can
 202          * refill the WL pool synchronous. */
 203         if (pool->used == pool->size || wl_pool->used == wl_pool->size) {
 204                 spin_unlock(&ubi->wl_lock);
 205                 up_read(&ubi->fm_eba_sem);
 206                 ret = ubi_update_fastmap(ubi);
 207                 if (ret) {
 208                         ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
 209                         down_read(&ubi->fm_eba_sem);
 210                         return -ENOSPC;
 211                 }
 212                 down_read(&ubi->fm_eba_sem);
 213                 spin_lock(&ubi->wl_lock);
 214         }
 215
 216         if (pool->used == pool->size) {
 217                 spin_unlock(&ubi->wl_lock);
 218                 attempts++;
 219                 if (attempts == 10) {
 220                         ubi_err(ubi, "Unable to get a free PEB from user WL pool");
 221                         ret = -ENOSPC;
 222                         goto out;
 223                 }
 224                 up_read(&ubi->fm_eba_sem);
 225                 ret = produce_free_peb(ubi);
 226                 if (ret < 0) {
 227                         down_read(&ubi->fm_eba_sem);
 228                         goto out;
 229                 }
 230                 goto again;
 231         }
 232
 233         ubi_assert(pool->used < pool->size);
 234         ret = pool->pebs[pool->used++];
 235         prot_queue_add(ubi, ubi->lookuptbl[ret]);
 236         spin_unlock(&ubi->wl_lock);
 237 out:
 238         return ret;
 239 }
 240
 241 /* get_peb_for_wl - returns a PEB to be used internally by the WL sub-system.
 242  *
 243  * @ubi: UBI device description object
 244  */
 245 static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
 246 {
 247         struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
 248         int pnum;
 249
 250         ubi_assert(rwsem_is_locked(&ubi->fm_eba_sem));
 251
 252         if (pool->used == pool->size) {
 253                 /* We cannot update the fastmap here because this
 254                  * function is called in atomic context.
 255                  * Let's fail here and refill/update it as soon as possible. */
 256                 if (!ubi->fm_work_scheduled) {
 257                         ubi->fm_work_scheduled = 1;
 258                         schedule_work(&ubi->fm_work);
 259                 }
 260                 return NULL;
 261         }
 262
 263         pnum = pool->pebs[pool->used++];
 264         return ubi->lookuptbl[pnum];
 265 }
 266
 267 /**
 268  * ubi_ensure_anchor_pebs - schedule wear-leveling to produce an anchor PEB.
 269  * @ubi: UBI device description object
 270  */
 271 int ubi_ensure_anchor_pebs(struct ubi_device *ubi)
 272 {
 273         struct ubi_work *wrk;
 274         struct ubi_wl_entry *anchor;
 275
 276         spin_lock(&ubi->wl_lock);
 277
 278         /* Do we already have an anchor? */
 279         if (ubi->fm_anchor) {
 280                 spin_unlock(&ubi->wl_lock);
 281                 return 0;
 282         }
 283
 284         /* See if we can find an anchor PEB on the list of free PEBs */
 285         anchor = ubi_wl_get_fm_peb(ubi, 1);
 286         if (anchor) {
 287                 ubi->fm_anchor = anchor;
 288                 spin_unlock(&ubi->wl_lock);
 289                 return 0;
 290         }
 291
 292         /* No luck, trigger wear leveling to produce a new anchor PEB */
 293         ubi->fm_do_produce_anchor = 1;
 294         if (ubi->wl_scheduled) {
 295                 spin_unlock(&ubi->wl_lock);
 296                 return 0;
 297         }
 298         ubi->wl_scheduled = 1;
 299         spin_unlock(&ubi->wl_lock);
 300
 301         wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
 302         if (!wrk) {
 303                 spin_lock(&ubi->wl_lock);
 304                 ubi->wl_scheduled = 0;
 305                 spin_unlock(&ubi->wl_lock);
 306                 return -ENOMEM;
 307         }
 308
 309         wrk->func = &wear_leveling_worker;
 310         __schedule_ubi_work(ubi, wrk);
 311         return 0;
 312 }
 313
 314 /**
 315  * ubi_wl_put_fm_peb - returns a PEB used in a fastmap to the wear-leveling
 316  * sub-system.
 317  * see: ubi_wl_put_peb()
 318  *
 319  * @ubi: UBI device description object
 320  * @fm_e: physical eraseblock to return
 321  * @lnum: the last used logical eraseblock number for the PEB
 322  * @torture: if this physical eraseblock has to be tortured
 323  */
 324 int ubi_wl_put_fm_peb(struct ubi_device *ubi, struct ubi_wl_entry *fm_e,
 325                       int lnum, int torture)
 326 {
 327         struct ubi_wl_entry *e;
 328         int vol_id, pnum = fm_e->pnum;
 329
 330         dbg_wl("PEB %d", pnum);
 331
 332         ubi_assert(pnum >= 0);
 333         ubi_assert(pnum < ubi->peb_count);
 334
 335         spin_lock(&ubi->wl_lock);
 336         e = ubi->lookuptbl[pnum];
 337
 338         /* This can happen if we recovered from a fastmap the very
 339          * first time and writing now a new one. In this case the wl system
 340          * has never seen any PEB used by the original fastmap.
 341          */
 342         if (!e) {
 343                 e = fm_e;
 344                 ubi_assert(e->ec >= 0);
 345                 ubi->lookuptbl[pnum] = e;
 346         }
 347
 348         spin_unlock(&ubi->wl_lock);
 349
 350         vol_id = lnum ? UBI_FM_DATA_VOLUME_ID : UBI_FM_SB_VOLUME_ID;
 351         return schedule_erase(ubi, e, vol_id, lnum, torture, true);
 352 }
 353
 354 /**
 355  * ubi_is_erase_work - checks whether a work is erase work.
 356  * @wrk: The work object to be checked
 357  */
 358 int ubi_is_erase_work(struct ubi_work *wrk)
 359 {
 360         return wrk->func == erase_worker;
 361 }
 362
 363 static void ubi_fastmap_close(struct ubi_device *ubi)
 364 {
 365         int i;
 366
 367         return_unused_pool_pebs(ubi, &ubi->fm_pool);
 368         return_unused_pool_pebs(ubi, &ubi->fm_wl_pool);
 369
 370         if (ubi->fm_anchor) {
 371                 return_unused_peb(ubi, ubi->fm_anchor);
 372                 ubi->fm_anchor = NULL;
 373         }
 374
 375         if (ubi->fm) {
 376                 for (i = 0; i < ubi->fm->used_blocks; i++)
 377                         kfree(ubi->fm->e[i]);
 378         }
 379         kfree(ubi->fm);
 380 }
 381
 382 /**
 383  * may_reserve_for_fm - tests whether a PEB shall be reserved for fastmap.
 384  * See find_mean_wl_entry()
 385  *
 386  * @ubi: UBI device description object
 387  * @e: physical eraseblock to return
 388  * @root: RB tree to test against.
 389  */
 390 static struct ubi_wl_entry *may_reserve_for_fm(struct ubi_device *ubi,
 391                                            struct ubi_wl_entry *e,
 392                                            struct rb_root *root) {
 393         if (e && !ubi->fm_disabled && !ubi->fm &&
 394             e->pnum < UBI_FM_MAX_START)
 395                 e = rb_entry(rb_next(root->rb_node),
 396                              struct ubi_wl_entry, u.rb);
 397
 398         return e;
 399 }