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 <richard@nod.at>
   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         if (ubi->fm_anchor) {
 120                 wl_tree_add(ubi->fm_anchor, &ubi->free);
 121                 ubi->free_count++;
 122         }
 123         if (ubi->fm_next_anchor) {
 124                 wl_tree_add(ubi->fm_next_anchor, &ubi->free);
 125                 ubi->free_count++;
 126         }
 127
 128         /* All available PEBs are in ubi->free, now is the time to get
 129          * the best anchor PEBs.
 130          */
 131         ubi->fm_anchor = ubi_wl_get_fm_peb(ubi, 1);
 132         ubi->fm_next_anchor = ubi_wl_get_fm_peb(ubi, 1);
 133
 134         for (;;) {
 135                 enough = 0;
 136                 if (pool->size < pool->max_size) {
 137                         if (!ubi->free.rb_node)
 138                                 break;
 139
 140                         e = wl_get_wle(ubi);
 141                         if (!e)
 142                                 break;
 143
 144                         pool->pebs[pool->size] = e->pnum;
 145                         pool->size++;
 146                 } else
 147                         enough++;
 148
 149                 if (wl_pool->size < wl_pool->max_size) {
 150                         if (!ubi->free.rb_node ||
 151                            (ubi->free_count - ubi->beb_rsvd_pebs < 5))
 152                                 break;
 153
 154                         e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
 155                         self_check_in_wl_tree(ubi, e, &ubi->free);
 156                         rb_erase(&e->u.rb, &ubi->free);
 157                         ubi->free_count--;
 158
 159                         wl_pool->pebs[wl_pool->size] = e->pnum;
 160                         wl_pool->size++;
 161                 } else
 162                         enough++;
 163
 164                 if (enough == 2)
 165                         break;
 166         }
 167
 168         wl_pool->used = 0;
 169         pool->used = 0;
 170
 171         spin_unlock(&ubi->wl_lock);
 172 }
 173
 174 /**
 175  * produce_free_peb - produce a free physical eraseblock.
 176  * @ubi: UBI device description object
 177  *
 178  * This function tries to make a free PEB by means of synchronous execution of
 179  * pending works. This may be needed if, for example the background thread is
 180  * disabled. Returns zero in case of success and a negative error code in case
 181  * of failure.
 182  */
 183 static int produce_free_peb(struct ubi_device *ubi)
 184 {
 185         int err;
 186
 187         while (!ubi->free.rb_node && ubi->works_count) {
 188                 dbg_wl("do one work synchronously");
 189                 err = do_work(ubi);
 190
 191                 if (err)
 192                         return err;
 193         }
 194
 195         return 0;
 196 }
 197
 198 /**
 199  * ubi_wl_get_peb - get a physical eraseblock.
 200  * @ubi: UBI device description object
 201  *
 202  * This function returns a physical eraseblock in case of success and a
 203  * negative error code in case of failure.
 204  * Returns with ubi->fm_eba_sem held in read mode!
 205  */
 206 int ubi_wl_get_peb(struct ubi_device *ubi)
 207 {
 208         int ret, attempts = 0;
 209         struct ubi_fm_pool *pool = &ubi->fm_pool;
 210         struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
 211
 212 again:
 213         down_read(&ubi->fm_eba_sem);
 214         spin_lock(&ubi->wl_lock);
 215
 216         /* We check here also for the WL pool because at this point we can
 217          * refill the WL pool synchronous. */
 218         if (pool->used == pool->size || wl_pool->used == wl_pool->size) {
 219                 spin_unlock(&ubi->wl_lock);
 220                 up_read(&ubi->fm_eba_sem);
 221                 ret = ubi_update_fastmap(ubi);
 222                 if (ret) {
 223                         ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
 224                         down_read(&ubi->fm_eba_sem);
 225                         return -ENOSPC;
 226                 }
 227                 down_read(&ubi->fm_eba_sem);
 228                 spin_lock(&ubi->wl_lock);
 229         }
 230
 231         if (pool->used == pool->size) {
 232                 spin_unlock(&ubi->wl_lock);
 233                 attempts++;
 234                 if (attempts == 10) {
 235                         ubi_err(ubi, "Unable to get a free PEB from user WL pool");
 236                         ret = -ENOSPC;
 237                         goto out;
 238                 }
 239                 up_read(&ubi->fm_eba_sem);
 240                 ret = produce_free_peb(ubi);
 241                 if (ret < 0) {
 242                         down_read(&ubi->fm_eba_sem);
 243                         goto out;
 244                 }
 245                 goto again;
 246         }
 247
 248         ubi_assert(pool->used < pool->size);
 249         ret = pool->pebs[pool->used++];
 250         prot_queue_add(ubi, ubi->lookuptbl[ret]);
 251         spin_unlock(&ubi->wl_lock);
 252 out:
 253         return ret;
 254 }
 255
 256 /* get_peb_for_wl - returns a PEB to be used internally by the WL sub-system.
 257  *
 258  * @ubi: UBI device description object
 259  */
 260 static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
 261 {
 262         struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
 263         int pnum;
 264
 265         ubi_assert(rwsem_is_locked(&ubi->fm_eba_sem));
 266
 267         if (pool->used == pool->size) {
 268                 /* We cannot update the fastmap here because this
 269                  * function is called in atomic context.
 270                  * Let's fail here and refill/update it as soon as possible. */
 271                 if (!ubi->fm_work_scheduled) {
 272                         ubi->fm_work_scheduled = 1;
 273                         schedule_work(&ubi->fm_work);
 274                 }
 275                 return NULL;
 276         }
 277
 278         pnum = pool->pebs[pool->used++];
 279         return ubi->lookuptbl[pnum];
 280 }
 281
 282 /**
 283  * ubi_ensure_anchor_pebs - schedule wear-leveling to produce an anchor PEB.
 284  * @ubi: UBI device description object
 285  */
 286 int ubi_ensure_anchor_pebs(struct ubi_device *ubi)
 287 {
 288         struct ubi_work *wrk;
 289
 290         spin_lock(&ubi->wl_lock);
 291
 292         /* Do we have a next anchor? */
 293         if (!ubi->fm_next_anchor) {
 294                 ubi->fm_next_anchor = ubi_wl_get_fm_peb(ubi, 1);
 295                 if (!ubi->fm_next_anchor)
 296                         /* Tell wear leveling to produce a new anchor PEB */
 297                         ubi->fm_do_produce_anchor = 1;
 298         }
 299
 300         /* Do wear leveling to get a new anchor PEB or check the
 301          * existing next anchor candidate.
 302          */
 303         if (ubi->wl_scheduled) {
 304                 spin_unlock(&ubi->wl_lock);
 305                 return 0;
 306         }
 307         ubi->wl_scheduled = 1;
 308         spin_unlock(&ubi->wl_lock);
 309
 310         wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
 311         if (!wrk) {
 312                 spin_lock(&ubi->wl_lock);
 313                 ubi->wl_scheduled = 0;
 314                 spin_unlock(&ubi->wl_lock);
 315                 return -ENOMEM;
 316         }
 317
 318         wrk->func = &wear_leveling_worker;
 319         __schedule_ubi_work(ubi, wrk);
 320         return 0;
 321 }
 322
 323 /**
 324  * ubi_wl_put_fm_peb - returns a PEB used in a fastmap to the wear-leveling
 325  * sub-system.
 326  * see: ubi_wl_put_peb()
 327  *
 328  * @ubi: UBI device description object
 329  * @fm_e: physical eraseblock to return
 330  * @lnum: the last used logical eraseblock number for the PEB
 331  * @torture: if this physical eraseblock has to be tortured
 332  */
 333 int ubi_wl_put_fm_peb(struct ubi_device *ubi, struct ubi_wl_entry *fm_e,
 334                       int lnum, int torture)
 335 {
 336         struct ubi_wl_entry *e;
 337         int vol_id, pnum = fm_e->pnum;
 338
 339         dbg_wl("PEB %d", pnum);
 340
 341         ubi_assert(pnum >= 0);
 342         ubi_assert(pnum < ubi->peb_count);
 343
 344         spin_lock(&ubi->wl_lock);
 345         e = ubi->lookuptbl[pnum];
 346
 347         /* This can happen if we recovered from a fastmap the very
 348          * first time and writing now a new one. In this case the wl system
 349          * has never seen any PEB used by the original fastmap.
 350          */
 351         if (!e) {
 352                 e = fm_e;
 353                 ubi_assert(e->ec >= 0);
 354                 ubi->lookuptbl[pnum] = e;
 355         }
 356
 357         spin_unlock(&ubi->wl_lock);
 358
 359         vol_id = lnum ? UBI_FM_DATA_VOLUME_ID : UBI_FM_SB_VOLUME_ID;
 360         return schedule_erase(ubi, e, vol_id, lnum, torture, true);
 361 }
 362
 363 /**
 364  * ubi_is_erase_work - checks whether a work is erase work.
 365  * @wrk: The work object to be checked
 366  */
 367 int ubi_is_erase_work(struct ubi_work *wrk)
 368 {
 369         return wrk->func == erase_worker;
 370 }
 371
 372 static void ubi_fastmap_close(struct ubi_device *ubi)
 373 {
 374         int i;
 375
 376         return_unused_pool_pebs(ubi, &ubi->fm_pool);
 377         return_unused_pool_pebs(ubi, &ubi->fm_wl_pool);
 378
 379         if (ubi->fm_anchor) {
 380                 return_unused_peb(ubi, ubi->fm_anchor);
 381                 ubi->fm_anchor = NULL;
 382         }
 383
 384         if (ubi->fm_next_anchor) {
 385                 return_unused_peb(ubi, ubi->fm_next_anchor);
 386                 ubi->fm_next_anchor = NULL;
 387         }
 388
 389         if (ubi->fm) {
 390                 for (i = 0; i < ubi->fm->used_blocks; i++)
 391                         kfree(ubi->fm->e[i]);
 392         }
 393         kfree(ubi->fm);
 394 }
 395
 396 /**
 397  * may_reserve_for_fm - tests whether a PEB shall be reserved for fastmap.
 398  * See find_mean_wl_entry()
 399  *
 400  * @ubi: UBI device description object
 401  * @e: physical eraseblock to return
 402  * @root: RB tree to test against.
 403  */
 404 static struct ubi_wl_entry *may_reserve_for_fm(struct ubi_device *ubi,
 405                                            struct ubi_wl_entry *e,
 406                                            struct rb_root *root) {
 407         if (e && !ubi->fm_disabled && !ubi->fm &&
 408             e->pnum < UBI_FM_MAX_START)
 409                 e = rb_entry(rb_next(root->rb_node),
 410                              struct ubi_wl_entry, u.rb);
 411
 412         return e;
 413 }