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