drivers/lightnvm/rrpc.c

   1 /*
   2  * Copyright (C) 2015 IT University of Copenhagen
   3  * Initial release: Matias Bjorling <m@bjorling.me>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License version
   7  * 2 as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * Implementation of a Round-robin page-based Hybrid FTL for Open-channel SSDs.
  15  */
  16
  17 #include "rrpc.h"
  18
  19 static struct kmem_cache *rrpc_gcb_cache, *rrpc_rq_cache;
  20 static DECLARE_RWSEM(rrpc_lock);
  21
  22 static int rrpc_submit_io(struct rrpc *rrpc, struct bio *bio,
  23                                 struct nvm_rq *rqd, unsigned long flags);
  24
  25 #define rrpc_for_each_lun(rrpc, rlun, i) \
  26                 for ((i) = 0, rlun = &(rrpc)->luns[0]; \
  27                         (i) < (rrpc)->nr_luns; (i)++, rlun = &(rrpc)->luns[(i)])
  28
  29 static void rrpc_page_invalidate(struct rrpc *rrpc, struct rrpc_addr *a)
  30 {
  31         struct rrpc_block *rblk = a->rblk;
  32         unsigned int pg_offset;
  33
  34         lockdep_assert_held(&rrpc->rev_lock);
  35
  36         if (a->addr == ADDR_EMPTY || !rblk)
  37                 return;
  38
  39         spin_lock(&rblk->lock);
  40
  41         div_u64_rem(a->addr, rrpc->dev->sec_per_blk, &pg_offset);
  42         WARN_ON(test_and_set_bit(pg_offset, rblk->invalid_pages));
  43         rblk->nr_invalid_pages++;
  44
  45         spin_unlock(&rblk->lock);
  46
  47         rrpc->rev_trans_map[a->addr - rrpc->poffset].addr = ADDR_EMPTY;
  48 }
  49
  50 static void rrpc_invalidate_range(struct rrpc *rrpc, sector_t slba,
  51                                                                 unsigned len)
  52 {
  53         sector_t i;
  54
  55         spin_lock(&rrpc->rev_lock);
  56         for (i = slba; i < slba + len; i++) {
  57                 struct rrpc_addr *gp = &rrpc->trans_map[i];
  58
  59                 rrpc_page_invalidate(rrpc, gp);
  60                 gp->rblk = NULL;
  61         }
  62         spin_unlock(&rrpc->rev_lock);
  63 }
  64
  65 static struct nvm_rq *rrpc_inflight_laddr_acquire(struct rrpc *rrpc,
  66                                         sector_t laddr, unsigned int pages)
  67 {
  68         struct nvm_rq *rqd;
  69         struct rrpc_inflight_rq *inf;
  70
  71         rqd = mempool_alloc(rrpc->rq_pool, GFP_ATOMIC);
  72         if (!rqd)
  73                 return ERR_PTR(-ENOMEM);
  74
  75         inf = rrpc_get_inflight_rq(rqd);
  76         if (rrpc_lock_laddr(rrpc, laddr, pages, inf)) {
  77                 mempool_free(rqd, rrpc->rq_pool);
  78                 return NULL;
  79         }
  80
  81         return rqd;
  82 }
  83
  84 static void rrpc_inflight_laddr_release(struct rrpc *rrpc, struct nvm_rq *rqd)
  85 {
  86         struct rrpc_inflight_rq *inf = rrpc_get_inflight_rq(rqd);
  87
  88         rrpc_unlock_laddr(rrpc, inf);
  89
  90         mempool_free(rqd, rrpc->rq_pool);
  91 }
  92
  93 static void rrpc_discard(struct rrpc *rrpc, struct bio *bio)
  94 {
  95         sector_t slba = bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
  96         sector_t len = bio->bi_iter.bi_size / RRPC_EXPOSED_PAGE_SIZE;
  97         struct nvm_rq *rqd;
  98
  99         do {
 100                 rqd = rrpc_inflight_laddr_acquire(rrpc, slba, len);
 101                 schedule();
 102         } while (!rqd);
 103
 104         if (IS_ERR(rqd)) {
 105                 pr_err("rrpc: unable to acquire inflight IO\n");
 106                 bio_io_error(bio);
 107                 return;
 108         }
 109
 110         rrpc_invalidate_range(rrpc, slba, len);
 111         rrpc_inflight_laddr_release(rrpc, rqd);
 112 }
 113
 114 static int block_is_full(struct rrpc *rrpc, struct rrpc_block *rblk)
 115 {
 116         return (rblk->next_page == rrpc->dev->sec_per_blk);
 117 }
 118
 119 /* Calculate relative addr for the given block, considering instantiated LUNs */
 120 static u64 block_to_rel_addr(struct rrpc *rrpc, struct rrpc_block *rblk)
 121 {
 122         struct nvm_block *blk = rblk->parent;
 123         int lun_blk = blk->id % (rrpc->dev->blks_per_lun * rrpc->nr_luns);
 124
 125         return lun_blk * rrpc->dev->sec_per_blk;
 126 }
 127
 128 /* Calculate global addr for the given block */
 129 static u64 block_to_addr(struct rrpc *rrpc, struct rrpc_block *rblk)
 130 {
 131         struct nvm_block *blk = rblk->parent;
 132
 133         return blk->id * rrpc->dev->sec_per_blk;
 134 }
 135
 136 static struct ppa_addr linear_to_generic_addr(struct nvm_dev *dev,
 137                                                         struct ppa_addr r)
 138 {
 139         struct ppa_addr l;
 140         int secs, pgs, blks, luns;
 141         sector_t ppa = r.ppa;
 142
 143         l.ppa = 0;
 144
 145         div_u64_rem(ppa, dev->sec_per_pg, &secs);
 146         l.g.sec = secs;
 147
 148         sector_div(ppa, dev->sec_per_pg);
 149         div_u64_rem(ppa, dev->pgs_per_blk, &pgs);
 150         l.g.pg = pgs;
 151
 152         sector_div(ppa, dev->pgs_per_blk);
 153         div_u64_rem(ppa, dev->blks_per_lun, &blks);
 154         l.g.blk = blks;
 155
 156         sector_div(ppa, dev->blks_per_lun);
 157         div_u64_rem(ppa, dev->luns_per_chnl, &luns);
 158         l.g.lun = luns;
 159
 160         sector_div(ppa, dev->luns_per_chnl);
 161         l.g.ch = ppa;
 162
 163         return l;
 164 }
 165
 166 static struct ppa_addr rrpc_ppa_to_gaddr(struct nvm_dev *dev, u64 addr)
 167 {
 168         struct ppa_addr paddr;
 169
 170         paddr.ppa = addr;
 171         return linear_to_generic_addr(dev, paddr);
 172 }
 173
 174 /* requires lun->lock taken */
 175 static void rrpc_set_lun_cur(struct rrpc_lun *rlun, struct rrpc_block *rblk)
 176 {
 177         struct rrpc *rrpc = rlun->rrpc;
 178
 179         BUG_ON(!rblk);
 180
 181         if (rlun->cur) {
 182                 spin_lock(&rlun->cur->lock);
 183                 WARN_ON(!block_is_full(rrpc, rlun->cur));
 184                 spin_unlock(&rlun->cur->lock);
 185         }
 186         rlun->cur = rblk;
 187 }
 188
 189 static struct rrpc_block *rrpc_get_blk(struct rrpc *rrpc, struct rrpc_lun *rlun,
 190                                                         unsigned long flags)
 191 {
 192         struct nvm_lun *lun = rlun->parent;
 193         struct nvm_block *blk;
 194         struct rrpc_block *rblk;
 195
 196         spin_lock(&lun->lock);
 197         blk = nvm_get_blk_unlocked(rrpc->dev, rlun->parent, flags);
 198         if (!blk) {
 199                 pr_err("nvm: rrpc: cannot get new block from media manager\n");
 200                 spin_unlock(&lun->lock);
 201                 return NULL;
 202         }
 203
 204         rblk = rrpc_get_rblk(rlun, blk->id);
 205         list_add_tail(&rblk->list, &rlun->open_list);
 206         spin_unlock(&lun->lock);
 207
 208         blk->priv = rblk;
 209         bitmap_zero(rblk->invalid_pages, rrpc->dev->sec_per_blk);
 210         rblk->next_page = 0;
 211         rblk->nr_invalid_pages = 0;
 212         atomic_set(&rblk->data_cmnt_size, 0);
 213
 214         return rblk;
 215 }
 216
 217 static void rrpc_put_blk(struct rrpc *rrpc, struct rrpc_block *rblk)
 218 {
 219         struct rrpc_lun *rlun = rblk->rlun;
 220         struct nvm_lun *lun = rlun->parent;
 221
 222         spin_lock(&lun->lock);
 223         nvm_put_blk_unlocked(rrpc->dev, rblk->parent);
 224         list_del(&rblk->list);
 225         spin_unlock(&lun->lock);
 226 }
 227
 228 static void rrpc_put_blks(struct rrpc *rrpc)
 229 {
 230         struct rrpc_lun *rlun;
 231         int i;
 232
 233         for (i = 0; i < rrpc->nr_luns; i++) {
 234                 rlun = &rrpc->luns[i];
 235                 if (rlun->cur)
 236                         rrpc_put_blk(rrpc, rlun->cur);
 237                 if (rlun->gc_cur)
 238                         rrpc_put_blk(rrpc, rlun->gc_cur);
 239         }
 240 }
 241
 242 static struct rrpc_lun *get_next_lun(struct rrpc *rrpc)
 243 {
 244         int next = atomic_inc_return(&rrpc->next_lun);
 245
 246         return &rrpc->luns[next % rrpc->nr_luns];
 247 }
 248
 249 static void rrpc_gc_kick(struct rrpc *rrpc)
 250 {
 251         struct rrpc_lun *rlun;
 252         unsigned int i;
 253
 254         for (i = 0; i < rrpc->nr_luns; i++) {
 255                 rlun = &rrpc->luns[i];
 256                 queue_work(rrpc->krqd_wq, &rlun->ws_gc);
 257         }
 258 }
 259
 260 /*
 261  * timed GC every interval.
 262  */
 263 static void rrpc_gc_timer(unsigned long data)
 264 {
 265         struct rrpc *rrpc = (struct rrpc *)data;
 266
 267         rrpc_gc_kick(rrpc);
 268         mod_timer(&rrpc->gc_timer, jiffies + msecs_to_jiffies(10));
 269 }
 270
 271 static void rrpc_end_sync_bio(struct bio *bio)
 272 {
 273         struct completion *waiting = bio->bi_private;
 274
 275         if (bio->bi_error)
 276                 pr_err("nvm: gc request failed (%u).\n", bio->bi_error);
 277
 278         complete(waiting);
 279 }
 280
 281 /*
 282  * rrpc_move_valid_pages -- migrate live data off the block
 283  * @rrpc: the 'rrpc' structure
 284  * @block: the block from which to migrate live pages
 285  *
 286  * Description:
 287  *   GC algorithms may call this function to migrate remaining live
 288  *   pages off the block prior to erasing it. This function blocks
 289  *   further execution until the operation is complete.
 290  */
 291 static int rrpc_move_valid_pages(struct rrpc *rrpc, struct rrpc_block *rblk)
 292 {
 293         struct request_queue *q = rrpc->dev->q;
 294         struct rrpc_rev_addr *rev;
 295         struct nvm_rq *rqd;
 296         struct bio *bio;
 297         struct page *page;
 298         int slot;
 299         int nr_sec_per_blk = rrpc->dev->sec_per_blk;
 300         u64 phys_addr;
 301         DECLARE_COMPLETION_ONSTACK(wait);
 302
 303         if (bitmap_full(rblk->invalid_pages, nr_sec_per_blk))
 304                 return 0;
 305
 306         bio = bio_alloc(GFP_NOIO, 1);
 307         if (!bio) {
 308                 pr_err("nvm: could not alloc bio to gc\n");
 309                 return -ENOMEM;
 310         }
 311
 312         page = mempool_alloc(rrpc->page_pool, GFP_NOIO);
 313         if (!page) {
 314                 bio_put(bio);
 315                 return -ENOMEM;
 316         }
 317
 318         while ((slot = find_first_zero_bit(rblk->invalid_pages,
 319                                             nr_sec_per_blk)) < nr_sec_per_blk) {
 320
 321                 /* Lock laddr */
 322                 phys_addr = rblk->parent->id * nr_sec_per_blk + slot;
 323
 324 try:
 325                 spin_lock(&rrpc->rev_lock);
 326                 /* Get logical address from physical to logical table */
 327                 rev = &rrpc->rev_trans_map[phys_addr - rrpc->poffset];
 328                 /* already updated by previous regular write */
 329                 if (rev->addr == ADDR_EMPTY) {
 330                         spin_unlock(&rrpc->rev_lock);
 331                         continue;
 332                 }
 333
 334                 rqd = rrpc_inflight_laddr_acquire(rrpc, rev->addr, 1);
 335                 if (IS_ERR_OR_NULL(rqd)) {
 336                         spin_unlock(&rrpc->rev_lock);
 337                         schedule();
 338                         goto try;
 339                 }
 340
 341                 spin_unlock(&rrpc->rev_lock);
 342
 343                 /* Perform read to do GC */
 344                 bio->bi_iter.bi_sector = rrpc_get_sector(rev->addr);
 345                 bio->bi_rw = READ;
 346                 bio->bi_private = &wait;
 347                 bio->bi_end_io = rrpc_end_sync_bio;
 348
 349                 /* TODO: may fail when EXP_PG_SIZE > PAGE_SIZE */
 350                 bio_add_pc_page(q, bio, page, RRPC_EXPOSED_PAGE_SIZE, 0);
 351
 352                 if (rrpc_submit_io(rrpc, bio, rqd, NVM_IOTYPE_GC)) {
 353                         pr_err("rrpc: gc read failed.\n");
 354                         rrpc_inflight_laddr_release(rrpc, rqd);
 355                         goto finished;
 356                 }
 357                 wait_for_completion_io(&wait);
 358                 if (bio->bi_error) {
 359                         rrpc_inflight_laddr_release(rrpc, rqd);
 360                         goto finished;
 361                 }
 362
 363                 bio_reset(bio);
 364                 reinit_completion(&wait);
 365
 366                 bio->bi_iter.bi_sector = rrpc_get_sector(rev->addr);
 367                 bio->bi_rw = WRITE;
 368                 bio->bi_private = &wait;
 369                 bio->bi_end_io = rrpc_end_sync_bio;
 370
 371                 bio_add_pc_page(q, bio, page, RRPC_EXPOSED_PAGE_SIZE, 0);
 372
 373                 /* turn the command around and write the data back to a new
 374                  * address
 375                  */
 376                 if (rrpc_submit_io(rrpc, bio, rqd, NVM_IOTYPE_GC)) {
 377                         pr_err("rrpc: gc write failed.\n");
 378                         rrpc_inflight_laddr_release(rrpc, rqd);
 379                         goto finished;
 380                 }
 381                 wait_for_completion_io(&wait);
 382
 383                 rrpc_inflight_laddr_release(rrpc, rqd);
 384                 if (bio->bi_error)
 385                         goto finished;
 386
 387                 bio_reset(bio);
 388         }
 389
 390 finished:
 391         mempool_free(page, rrpc->page_pool);
 392         bio_put(bio);
 393
 394         if (!bitmap_full(rblk->invalid_pages, nr_sec_per_blk)) {
 395                 pr_err("nvm: failed to garbage collect block\n");
 396                 return -EIO;
 397         }
 398
 399         return 0;
 400 }
 401
 402 static void rrpc_block_gc(struct work_struct *work)
 403 {
 404         struct rrpc_block_gc *gcb = container_of(work, struct rrpc_block_gc,
 405                                                                         ws_gc);
 406         struct rrpc *rrpc = gcb->rrpc;
 407         struct rrpc_block *rblk = gcb->rblk;
 408         struct nvm_dev *dev = rrpc->dev;
 409         struct nvm_lun *lun = rblk->parent->lun;
 410         struct rrpc_lun *rlun = &rrpc->luns[lun->id - rrpc->lun_offset];
 411
 412         mempool_free(gcb, rrpc->gcb_pool);
 413         pr_debug("nvm: block '%lu' being reclaimed\n", rblk->parent->id);
 414
 415         if (rrpc_move_valid_pages(rrpc, rblk))
 416                 goto put_back;
 417
 418         if (nvm_erase_blk(dev, rblk->parent))
 419                 goto put_back;
 420
 421         rrpc_put_blk(rrpc, rblk);
 422
 423         return;
 424
 425 put_back:
 426         spin_lock(&rlun->lock);
 427         list_add_tail(&rblk->prio, &rlun->prio_list);
 428         spin_unlock(&rlun->lock);
 429 }
 430
 431 /* the block with highest number of invalid pages, will be in the beginning
 432  * of the list
 433  */
 434 static struct rrpc_block *rblock_max_invalid(struct rrpc_block *ra,
 435                                                         struct rrpc_block *rb)
 436 {
 437         if (ra->nr_invalid_pages == rb->nr_invalid_pages)
 438                 return ra;
 439
 440         return (ra->nr_invalid_pages < rb->nr_invalid_pages) ? rb : ra;
 441 }
 442
 443 /* linearly find the block with highest number of invalid pages
 444  * requires lun->lock
 445  */
 446 static struct rrpc_block *block_prio_find_max(struct rrpc_lun *rlun)
 447 {
 448         struct list_head *prio_list = &rlun->prio_list;
 449         struct rrpc_block *rblock, *max;
 450
 451         BUG_ON(list_empty(prio_list));
 452
 453         max = list_first_entry(prio_list, struct rrpc_block, prio);
 454         list_for_each_entry(rblock, prio_list, prio)
 455                 max = rblock_max_invalid(max, rblock);
 456
 457         return max;
 458 }
 459
 460 static void rrpc_lun_gc(struct work_struct *work)
 461 {
 462         struct rrpc_lun *rlun = container_of(work, struct rrpc_lun, ws_gc);
 463         struct rrpc *rrpc = rlun->rrpc;
 464         struct nvm_lun *lun = rlun->parent;
 465         struct rrpc_block_gc *gcb;
 466         unsigned int nr_blocks_need;
 467
 468         nr_blocks_need = rrpc->dev->blks_per_lun / GC_LIMIT_INVERSE;
 469
 470         if (nr_blocks_need < rrpc->nr_luns)
 471                 nr_blocks_need = rrpc->nr_luns;
 472
 473         spin_lock(&rlun->lock);
 474         while (nr_blocks_need > lun->nr_free_blocks &&
 475                                         !list_empty(&rlun->prio_list)) {
 476                 struct rrpc_block *rblock = block_prio_find_max(rlun);
 477                 struct nvm_block *block = rblock->parent;
 478
 479                 if (!rblock->nr_invalid_pages)
 480                         break;
 481
 482                 gcb = mempool_alloc(rrpc->gcb_pool, GFP_ATOMIC);
 483                 if (!gcb)
 484                         break;
 485
 486                 list_del_init(&rblock->prio);
 487
 488                 BUG_ON(!block_is_full(rrpc, rblock));
 489
 490                 pr_debug("rrpc: selected block '%lu' for GC\n", block->id);
 491
 492                 gcb->rrpc = rrpc;
 493                 gcb->rblk = rblock;
 494                 INIT_WORK(&gcb->ws_gc, rrpc_block_gc);
 495
 496                 queue_work(rrpc->kgc_wq, &gcb->ws_gc);
 497
 498                 nr_blocks_need--;
 499         }
 500         spin_unlock(&rlun->lock);
 501
 502         /* TODO: Hint that request queue can be started again */
 503 }
 504
 505 static void rrpc_gc_queue(struct work_struct *work)
 506 {
 507         struct rrpc_block_gc *gcb = container_of(work, struct rrpc_block_gc,
 508                                                                         ws_gc);
 509         struct rrpc *rrpc = gcb->rrpc;
 510         struct rrpc_block *rblk = gcb->rblk;
 511         struct nvm_lun *lun = rblk->parent->lun;
 512         struct nvm_block *blk = rblk->parent;
 513         struct rrpc_lun *rlun = &rrpc->luns[lun->id - rrpc->lun_offset];
 514
 515         spin_lock(&rlun->lock);
 516         list_add_tail(&rblk->prio, &rlun->prio_list);
 517         spin_unlock(&rlun->lock);
 518
 519         spin_lock(&lun->lock);
 520         lun->nr_open_blocks--;
 521         lun->nr_closed_blocks++;
 522         blk->state &= ~NVM_BLK_ST_OPEN;
 523         blk->state |= NVM_BLK_ST_CLOSED;
 524         list_move_tail(&rblk->list, &rlun->closed_list);
 525         spin_unlock(&lun->lock);
 526
 527         mempool_free(gcb, rrpc->gcb_pool);
 528         pr_debug("nvm: block '%lu' is full, allow GC (sched)\n",
 529                                                         rblk->parent->id);
 530 }
 531
 532 static const struct block_device_operations rrpc_fops = {
 533         .owner          = THIS_MODULE,
 534 };
 535
 536 static struct rrpc_lun *rrpc_get_lun_rr(struct rrpc *rrpc, int is_gc)
 537 {
 538         unsigned int i;
 539         struct rrpc_lun *rlun, *max_free;
 540
 541         if (!is_gc)
 542                 return get_next_lun(rrpc);
 543
 544         /* during GC, we don't care about RR, instead we want to make
 545          * sure that we maintain evenness between the block luns.
 546          */
 547         max_free = &rrpc->luns[0];
 548         /* prevent GC-ing lun from devouring pages of a lun with
 549          * little free blocks. We don't take the lock as we only need an
 550          * estimate.
 551          */
 552         rrpc_for_each_lun(rrpc, rlun, i) {
 553                 if (rlun->parent->nr_free_blocks >
 554                                         max_free->parent->nr_free_blocks)
 555                         max_free = rlun;
 556         }
 557
 558         return max_free;
 559 }
 560
 561 static struct rrpc_addr *rrpc_update_map(struct rrpc *rrpc, sector_t laddr,
 562                                         struct rrpc_block *rblk, u64 paddr)
 563 {
 564         struct rrpc_addr *gp;
 565         struct rrpc_rev_addr *rev;
 566
 567         BUG_ON(laddr >= rrpc->nr_sects);
 568
 569         gp = &rrpc->trans_map[laddr];
 570         spin_lock(&rrpc->rev_lock);
 571         if (gp->rblk)
 572                 rrpc_page_invalidate(rrpc, gp);
 573
 574         gp->addr = paddr;
 575         gp->rblk = rblk;
 576
 577         rev = &rrpc->rev_trans_map[gp->addr - rrpc->poffset];
 578         rev->addr = laddr;
 579         spin_unlock(&rrpc->rev_lock);
 580
 581         return gp;
 582 }
 583
 584 static u64 rrpc_alloc_addr(struct rrpc *rrpc, struct rrpc_block *rblk)
 585 {
 586         u64 addr = ADDR_EMPTY;
 587
 588         spin_lock(&rblk->lock);
 589         if (block_is_full(rrpc, rblk))
 590                 goto out;
 591
 592         addr = block_to_addr(rrpc, rblk) + rblk->next_page;
 593
 594         rblk->next_page++;
 595 out:
 596         spin_unlock(&rblk->lock);
 597         return addr;
 598 }
 599
 600 /* Simple round-robin Logical to physical address translation.
 601  *
 602  * Retrieve the mapping using the active append point. Then update the ap for
 603  * the next write to the disk.
 604  *
 605  * Returns rrpc_addr with the physical address and block. Remember to return to
 606  * rrpc->addr_cache when request is finished.
 607  */
 608 static struct rrpc_addr *rrpc_map_page(struct rrpc *rrpc, sector_t laddr,
 609                                                                 int is_gc)
 610 {
 611         struct rrpc_lun *rlun;
 612         struct rrpc_block *rblk;
 613         struct nvm_lun *lun;
 614         u64 paddr;
 615
 616         rlun = rrpc_get_lun_rr(rrpc, is_gc);
 617         lun = rlun->parent;
 618
 619         if (!is_gc && lun->nr_free_blocks < rrpc->nr_luns * 4)
 620                 return NULL;
 621
 622         spin_lock(&rlun->lock);
 623
 624         rblk = rlun->cur;
 625 retry:
 626         paddr = rrpc_alloc_addr(rrpc, rblk);
 627
 628         if (paddr == ADDR_EMPTY) {
 629                 rblk = rrpc_get_blk(rrpc, rlun, 0);
 630                 if (rblk) {
 631                         rrpc_set_lun_cur(rlun, rblk);
 632                         goto retry;
 633                 }
 634
 635                 if (is_gc) {
 636                         /* retry from emergency gc block */
 637                         paddr = rrpc_alloc_addr(rrpc, rlun->gc_cur);
 638                         if (paddr == ADDR_EMPTY) {
 639                                 rblk = rrpc_get_blk(rrpc, rlun, 1);
 640                                 if (!rblk) {
 641                                         pr_err("rrpc: no more blocks");
 642                                         goto err;
 643                                 }
 644
 645                                 rlun->gc_cur = rblk;
 646                                 paddr = rrpc_alloc_addr(rrpc, rlun->gc_cur);
 647                         }
 648                         rblk = rlun->gc_cur;
 649                 }
 650         }
 651
 652         spin_unlock(&rlun->lock);
 653         return rrpc_update_map(rrpc, laddr, rblk, paddr);
 654 err:
 655         spin_unlock(&rlun->lock);
 656         return NULL;
 657 }
 658
 659 static void rrpc_run_gc(struct rrpc *rrpc, struct rrpc_block *rblk)
 660 {
 661         struct rrpc_block_gc *gcb;
 662
 663         gcb = mempool_alloc(rrpc->gcb_pool, GFP_ATOMIC);
 664         if (!gcb) {
 665                 pr_err("rrpc: unable to queue block for gc.");
 666                 return;
 667         }
 668
 669         gcb->rrpc = rrpc;
 670         gcb->rblk = rblk;
 671
 672         INIT_WORK(&gcb->ws_gc, rrpc_gc_queue);
 673         queue_work(rrpc->kgc_wq, &gcb->ws_gc);
 674 }
 675
 676 static void rrpc_end_io_write(struct rrpc *rrpc, struct rrpc_rq *rrqd,
 677                                                 sector_t laddr, uint8_t npages)
 678 {
 679         struct rrpc_addr *p;
 680         struct rrpc_block *rblk;
 681         struct nvm_lun *lun;
 682         int cmnt_size, i;
 683
 684         for (i = 0; i < npages; i++) {
 685                 p = &rrpc->trans_map[laddr + i];
 686                 rblk = p->rblk;
 687                 lun = rblk->parent->lun;
 688
 689                 cmnt_size = atomic_inc_return(&rblk->data_cmnt_size);
 690                 if (unlikely(cmnt_size == rrpc->dev->sec_per_blk))
 691                         rrpc_run_gc(rrpc, rblk);
 692         }
 693 }
 694
 695 static void rrpc_end_io(struct nvm_rq *rqd)
 696 {
 697         struct rrpc *rrpc = container_of(rqd->ins, struct rrpc, instance);
 698         struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
 699         uint8_t npages = rqd->nr_pages;
 700         sector_t laddr = rrpc_get_laddr(rqd->bio) - npages;
 701
 702         if (bio_data_dir(rqd->bio) == WRITE)
 703                 rrpc_end_io_write(rrpc, rrqd, laddr, npages);
 704
 705         bio_put(rqd->bio);
 706
 707         if (rrqd->flags & NVM_IOTYPE_GC)
 708                 return;
 709
 710         rrpc_unlock_rq(rrpc, rqd);
 711
 712         if (npages > 1)
 713                 nvm_dev_dma_free(rrpc->dev, rqd->ppa_list, rqd->dma_ppa_list);
 714         if (rqd->metadata)
 715                 nvm_dev_dma_free(rrpc->dev, rqd->metadata, rqd->dma_metadata);
 716
 717         mempool_free(rqd, rrpc->rq_pool);
 718 }
 719
 720 static int rrpc_read_ppalist_rq(struct rrpc *rrpc, struct bio *bio,
 721                         struct nvm_rq *rqd, unsigned long flags, int npages)
 722 {
 723         struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
 724         struct rrpc_addr *gp;
 725         sector_t laddr = rrpc_get_laddr(bio);
 726         int is_gc = flags & NVM_IOTYPE_GC;
 727         int i;
 728
 729         if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd)) {
 730                 nvm_dev_dma_free(rrpc->dev, rqd->ppa_list, rqd->dma_ppa_list);
 731                 return NVM_IO_REQUEUE;
 732         }
 733
 734         for (i = 0; i < npages; i++) {
 735                 /* We assume that mapping occurs at 4KB granularity */
 736                 BUG_ON(!(laddr + i >= 0 && laddr + i < rrpc->nr_sects));
 737                 gp = &rrpc->trans_map[laddr + i];
 738
 739                 if (gp->rblk) {
 740                         rqd->ppa_list[i] = rrpc_ppa_to_gaddr(rrpc->dev,
 741                                                                 gp->addr);
 742                 } else {
 743                         BUG_ON(is_gc);
 744                         rrpc_unlock_laddr(rrpc, r);
 745                         nvm_dev_dma_free(rrpc->dev, rqd->ppa_list,
 746                                                         rqd->dma_ppa_list);
 747                         return NVM_IO_DONE;
 748                 }
 749         }
 750
 751         rqd->opcode = NVM_OP_HBREAD;
 752
 753         return NVM_IO_OK;
 754 }
 755
 756 static int rrpc_read_rq(struct rrpc *rrpc, struct bio *bio, struct nvm_rq *rqd,
 757                                                         unsigned long flags)
 758 {
 759         struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
 760         int is_gc = flags & NVM_IOTYPE_GC;
 761         sector_t laddr = rrpc_get_laddr(bio);
 762         struct rrpc_addr *gp;
 763
 764         if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd))
 765                 return NVM_IO_REQUEUE;
 766
 767         BUG_ON(!(laddr >= 0 && laddr < rrpc->nr_sects));
 768         gp = &rrpc->trans_map[laddr];
 769
 770         if (gp->rblk) {
 771                 rqd->ppa_addr = rrpc_ppa_to_gaddr(rrpc->dev, gp->addr);
 772         } else {
 773                 BUG_ON(is_gc);
 774                 rrpc_unlock_rq(rrpc, rqd);
 775                 return NVM_IO_DONE;
 776         }
 777
 778         rqd->opcode = NVM_OP_HBREAD;
 779         rrqd->addr = gp;
 780
 781         return NVM_IO_OK;
 782 }
 783
 784 static int rrpc_write_ppalist_rq(struct rrpc *rrpc, struct bio *bio,
 785                         struct nvm_rq *rqd, unsigned long flags, int npages)
 786 {
 787         struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
 788         struct rrpc_addr *p;
 789         sector_t laddr = rrpc_get_laddr(bio);
 790         int is_gc = flags & NVM_IOTYPE_GC;
 791         int i;
 792
 793         if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd)) {
 794                 nvm_dev_dma_free(rrpc->dev, rqd->ppa_list, rqd->dma_ppa_list);
 795                 return NVM_IO_REQUEUE;
 796         }
 797
 798         for (i = 0; i < npages; i++) {
 799                 /* We assume that mapping occurs at 4KB granularity */
 800                 p = rrpc_map_page(rrpc, laddr + i, is_gc);
 801                 if (!p) {
 802                         BUG_ON(is_gc);
 803                         rrpc_unlock_laddr(rrpc, r);
 804                         nvm_dev_dma_free(rrpc->dev, rqd->ppa_list,
 805                                                         rqd->dma_ppa_list);
 806                         rrpc_gc_kick(rrpc);
 807                         return NVM_IO_REQUEUE;
 808                 }
 809
 810                 rqd->ppa_list[i] = rrpc_ppa_to_gaddr(rrpc->dev,
 811                                                                 p->addr);
 812         }
 813
 814         rqd->opcode = NVM_OP_HBWRITE;
 815
 816         return NVM_IO_OK;
 817 }
 818
 819 static int rrpc_write_rq(struct rrpc *rrpc, struct bio *bio,
 820                                 struct nvm_rq *rqd, unsigned long flags)
 821 {
 822         struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
 823         struct rrpc_addr *p;
 824         int is_gc = flags & NVM_IOTYPE_GC;
 825         sector_t laddr = rrpc_get_laddr(bio);
 826
 827         if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd))
 828                 return NVM_IO_REQUEUE;
 829
 830         p = rrpc_map_page(rrpc, laddr, is_gc);
 831         if (!p) {
 832                 BUG_ON(is_gc);
 833                 rrpc_unlock_rq(rrpc, rqd);
 834                 rrpc_gc_kick(rrpc);
 835                 return NVM_IO_REQUEUE;
 836         }
 837
 838         rqd->ppa_addr = rrpc_ppa_to_gaddr(rrpc->dev, p->addr);
 839         rqd->opcode = NVM_OP_HBWRITE;
 840         rrqd->addr = p;
 841
 842         return NVM_IO_OK;
 843 }
 844
 845 static int rrpc_setup_rq(struct rrpc *rrpc, struct bio *bio,
 846                         struct nvm_rq *rqd, unsigned long flags, uint8_t npages)
 847 {
 848         if (npages > 1) {
 849                 rqd->ppa_list = nvm_dev_dma_alloc(rrpc->dev, GFP_KERNEL,
 850                                                         &rqd->dma_ppa_list);
 851                 if (!rqd->ppa_list) {
 852                         pr_err("rrpc: not able to allocate ppa list\n");
 853                         return NVM_IO_ERR;
 854                 }
 855
 856                 if (bio_rw(bio) == WRITE)
 857                         return rrpc_write_ppalist_rq(rrpc, bio, rqd, flags,
 858                                                                         npages);
 859
 860                 return rrpc_read_ppalist_rq(rrpc, bio, rqd, flags, npages);
 861         }
 862
 863         if (bio_rw(bio) == WRITE)
 864                 return rrpc_write_rq(rrpc, bio, rqd, flags);
 865
 866         return rrpc_read_rq(rrpc, bio, rqd, flags);
 867 }
 868
 869 static int rrpc_submit_io(struct rrpc *rrpc, struct bio *bio,
 870                                 struct nvm_rq *rqd, unsigned long flags)
 871 {
 872         int err;
 873         struct rrpc_rq *rrq = nvm_rq_to_pdu(rqd);
 874         uint8_t nr_pages = rrpc_get_pages(bio);
 875         int bio_size = bio_sectors(bio) << 9;
 876
 877         if (bio_size < rrpc->dev->sec_size)
 878                 return NVM_IO_ERR;
 879         else if (bio_size > rrpc->dev->max_rq_size)
 880                 return NVM_IO_ERR;
 881
 882         err = rrpc_setup_rq(rrpc, bio, rqd, flags, nr_pages);
 883         if (err)
 884                 return err;
 885
 886         bio_get(bio);
 887         rqd->bio = bio;
 888         rqd->ins = &rrpc->instance;
 889         rqd->nr_pages = nr_pages;
 890         rrq->flags = flags;
 891
 892         err = nvm_submit_io(rrpc->dev, rqd);
 893         if (err) {
 894                 pr_err("rrpc: I/O submission failed: %d\n", err);
 895                 bio_put(bio);
 896                 if (!(flags & NVM_IOTYPE_GC)) {
 897                         rrpc_unlock_rq(rrpc, rqd);
 898                         if (rqd->nr_pages > 1)
 899                                 nvm_dev_dma_free(rrpc->dev,
 900                         rqd->ppa_list, rqd->dma_ppa_list);
 901                 }
 902                 return NVM_IO_ERR;
 903         }
 904
 905         return NVM_IO_OK;
 906 }
 907
 908 static blk_qc_t rrpc_make_rq(struct request_queue *q, struct bio *bio)
 909 {
 910         struct rrpc *rrpc = q->queuedata;
 911         struct nvm_rq *rqd;
 912         int err;
 913
 914         if (bio->bi_rw & REQ_DISCARD) {
 915                 rrpc_discard(rrpc, bio);
 916                 return BLK_QC_T_NONE;
 917         }
 918
 919         rqd = mempool_alloc(rrpc->rq_pool, GFP_KERNEL);
 920         if (!rqd) {
 921                 pr_err_ratelimited("rrpc: not able to queue bio.");
 922                 bio_io_error(bio);
 923                 return BLK_QC_T_NONE;
 924         }
 925         memset(rqd, 0, sizeof(struct nvm_rq));
 926
 927         err = rrpc_submit_io(rrpc, bio, rqd, NVM_IOTYPE_NONE);
 928         switch (err) {
 929         case NVM_IO_OK:
 930                 return BLK_QC_T_NONE;
 931         case NVM_IO_ERR:
 932                 bio_io_error(bio);
 933                 break;
 934         case NVM_IO_DONE:
 935                 bio_endio(bio);
 936                 break;
 937         case NVM_IO_REQUEUE:
 938                 spin_lock(&rrpc->bio_lock);
 939                 bio_list_add(&rrpc->requeue_bios, bio);
 940                 spin_unlock(&rrpc->bio_lock);
 941                 queue_work(rrpc->kgc_wq, &rrpc->ws_requeue);
 942                 break;
 943         }
 944
 945         mempool_free(rqd, rrpc->rq_pool);
 946         return BLK_QC_T_NONE;
 947 }
 948
 949 static void rrpc_requeue(struct work_struct *work)
 950 {
 951         struct rrpc *rrpc = container_of(work, struct rrpc, ws_requeue);
 952         struct bio_list bios;
 953         struct bio *bio;
 954
 955         bio_list_init(&bios);
 956
 957         spin_lock(&rrpc->bio_lock);
 958         bio_list_merge(&bios, &rrpc->requeue_bios);
 959         bio_list_init(&rrpc->requeue_bios);
 960         spin_unlock(&rrpc->bio_lock);
 961
 962         while ((bio = bio_list_pop(&bios)))
 963                 rrpc_make_rq(rrpc->disk->queue, bio);
 964 }
 965
 966 static void rrpc_gc_free(struct rrpc *rrpc)
 967 {
 968         struct rrpc_lun *rlun;
 969         int i;
 970
 971         if (rrpc->krqd_wq)
 972                 destroy_workqueue(rrpc->krqd_wq);
 973
 974         if (rrpc->kgc_wq)
 975                 destroy_workqueue(rrpc->kgc_wq);
 976
 977         if (!rrpc->luns)
 978                 return;
 979
 980         for (i = 0; i < rrpc->nr_luns; i++) {
 981                 rlun = &rrpc->luns[i];
 982
 983                 if (!rlun->blocks)
 984                         break;
 985                 vfree(rlun->blocks);
 986         }
 987 }
 988
 989 static int rrpc_gc_init(struct rrpc *rrpc)
 990 {
 991         rrpc->krqd_wq = alloc_workqueue("rrpc-lun", WQ_MEM_RECLAIM|WQ_UNBOUND,
 992                                                                 rrpc->nr_luns);
 993         if (!rrpc->krqd_wq)
 994                 return -ENOMEM;
 995
 996         rrpc->kgc_wq = alloc_workqueue("rrpc-bg", WQ_MEM_RECLAIM, 1);
 997         if (!rrpc->kgc_wq)
 998                 return -ENOMEM;
 999
1000         setup_timer(&rrpc->gc_timer, rrpc_gc_timer, (unsigned long)rrpc);
1001
1002         return 0;
1003 }
1004
1005 static void rrpc_map_free(struct rrpc *rrpc)
1006 {
1007         vfree(rrpc->rev_trans_map);
1008         vfree(rrpc->trans_map);
1009 }
1010
1011 static int rrpc_l2p_update(u64 slba, u32 nlb, __le64 *entries, void *private)
1012 {
1013         struct rrpc *rrpc = (struct rrpc *)private;
1014         struct nvm_dev *dev = rrpc->dev;
1015         struct rrpc_addr *addr = rrpc->trans_map + slba;
1016         struct rrpc_rev_addr *raddr = rrpc->rev_trans_map;
1017         u64 elba = slba + nlb;
1018         u64 i;
1019
1020         if (unlikely(elba > dev->total_secs)) {
1021                 pr_err("nvm: L2P data from device is out of bounds!\n");
1022                 return -EINVAL;
1023         }
1024
1025         for (i = 0; i < nlb; i++) {
1026                 u64 pba = le64_to_cpu(entries[i]);
1027                 unsigned int mod;
1028                 /* LNVM treats address-spaces as silos, LBA and PBA are
1029                  * equally large and zero-indexed.
1030                  */
1031                 if (unlikely(pba >= dev->total_secs && pba != U64_MAX)) {
1032                         pr_err("nvm: L2P data entry is out of bounds!\n");
1033                         return -EINVAL;
1034                 }
1035
1036                 /* Address zero is a special one. The first page on a disk is
1037                  * protected. As it often holds internal device boot
1038                  * information.
1039                  */
1040                 if (!pba)
1041                         continue;
1042
1043                 div_u64_rem(pba, rrpc->nr_sects, &mod);
1044
1045                 addr[i].addr = pba;
1046                 raddr[mod].addr = slba + i;
1047         }
1048
1049         return 0;
1050 }
1051
1052 static int rrpc_map_init(struct rrpc *rrpc)
1053 {
1054         struct nvm_dev *dev = rrpc->dev;
1055         sector_t i;
1056         int ret;
1057
1058         rrpc->trans_map = vzalloc(sizeof(struct rrpc_addr) * rrpc->nr_sects);
1059         if (!rrpc->trans_map)
1060                 return -ENOMEM;
1061
1062         rrpc->rev_trans_map = vmalloc(sizeof(struct rrpc_rev_addr)
1063                                                         * rrpc->nr_sects);
1064         if (!rrpc->rev_trans_map)
1065                 return -ENOMEM;
1066
1067         for (i = 0; i < rrpc->nr_sects; i++) {
1068                 struct rrpc_addr *p = &rrpc->trans_map[i];
1069                 struct rrpc_rev_addr *r = &rrpc->rev_trans_map[i];
1070
1071                 p->addr = ADDR_EMPTY;
1072                 r->addr = ADDR_EMPTY;
1073         }
1074
1075         if (!dev->ops->get_l2p_tbl)
1076                 return 0;
1077
1078         /* Bring up the mapping table from device */
1079         ret = dev->ops->get_l2p_tbl(dev, 0, dev->total_secs, rrpc_l2p_update,
1080                                                                         rrpc);
1081         if (ret) {
1082                 pr_err("nvm: rrpc: could not read L2P table.\n");
1083                 return -EINVAL;
1084         }
1085
1086         return 0;
1087 }
1088
1089
1090 /* Minimum pages needed within a lun */
1091 #define PAGE_POOL_SIZE 16
1092 #define ADDR_POOL_SIZE 64
1093
1094 static int rrpc_core_init(struct rrpc *rrpc)
1095 {
1096         down_write(&rrpc_lock);
1097         if (!rrpc_gcb_cache) {
1098                 rrpc_gcb_cache = kmem_cache_create("rrpc_gcb",
1099                                 sizeof(struct rrpc_block_gc), 0, 0, NULL);
1100                 if (!rrpc_gcb_cache) {
1101                         up_write(&rrpc_lock);
1102                         return -ENOMEM;
1103                 }
1104
1105                 rrpc_rq_cache = kmem_cache_create("rrpc_rq",
1106                                 sizeof(struct nvm_rq) + sizeof(struct rrpc_rq),
1107                                 0, 0, NULL);
1108                 if (!rrpc_rq_cache) {
1109                         kmem_cache_destroy(rrpc_gcb_cache);
1110                         up_write(&rrpc_lock);
1111                         return -ENOMEM;
1112                 }
1113         }
1114         up_write(&rrpc_lock);
1115
1116         rrpc->page_pool = mempool_create_page_pool(PAGE_POOL_SIZE, 0);
1117         if (!rrpc->page_pool)
1118                 return -ENOMEM;
1119
1120         rrpc->gcb_pool = mempool_create_slab_pool(rrpc->dev->nr_luns,
1121                                                                 rrpc_gcb_cache);
1122         if (!rrpc->gcb_pool)
1123                 return -ENOMEM;
1124
1125         rrpc->rq_pool = mempool_create_slab_pool(64, rrpc_rq_cache);
1126         if (!rrpc->rq_pool)
1127                 return -ENOMEM;
1128
1129         spin_lock_init(&rrpc->inflights.lock);
1130         INIT_LIST_HEAD(&rrpc->inflights.reqs);
1131
1132         return 0;
1133 }
1134
1135 static void rrpc_core_free(struct rrpc *rrpc)
1136 {
1137         mempool_destroy(rrpc->page_pool);
1138         mempool_destroy(rrpc->gcb_pool);
1139         mempool_destroy(rrpc->rq_pool);
1140 }
1141
1142 static void rrpc_luns_free(struct rrpc *rrpc)
1143 {
1144         kfree(rrpc->luns);
1145 }
1146
1147 static int rrpc_luns_init(struct rrpc *rrpc, int lun_begin, int lun_end)
1148 {
1149         struct nvm_dev *dev = rrpc->dev;
1150         struct rrpc_lun *rlun;
1151         int i, j;
1152
1153         if (dev->sec_per_blk > MAX_INVALID_PAGES_STORAGE * BITS_PER_LONG) {
1154                 pr_err("rrpc: number of pages per block too high.");
1155                 return -EINVAL;
1156         }
1157
1158         spin_lock_init(&rrpc->rev_lock);
1159
1160         rrpc->luns = kcalloc(rrpc->nr_luns, sizeof(struct rrpc_lun),
1161                                                                 GFP_KERNEL);
1162         if (!rrpc->luns)
1163                 return -ENOMEM;
1164
1165         /* 1:1 mapping */
1166         for (i = 0; i < rrpc->nr_luns; i++) {
1167                 struct nvm_lun *lun = dev->mt->get_lun(dev, lun_begin + i);
1168
1169                 rlun = &rrpc->luns[i];
1170                 rlun->rrpc = rrpc;
1171                 rlun->parent = lun;
1172                 INIT_LIST_HEAD(&rlun->prio_list);
1173                 INIT_LIST_HEAD(&rlun->open_list);
1174                 INIT_LIST_HEAD(&rlun->closed_list);
1175
1176                 INIT_WORK(&rlun->ws_gc, rrpc_lun_gc);
1177                 spin_lock_init(&rlun->lock);
1178
1179                 rrpc->total_blocks += dev->blks_per_lun;
1180                 rrpc->nr_sects += dev->sec_per_lun;
1181
1182                 rlun->blocks = vzalloc(sizeof(struct rrpc_block) *
1183                                                 rrpc->dev->blks_per_lun);
1184                 if (!rlun->blocks)
1185                         goto err;
1186
1187                 for (j = 0; j < rrpc->dev->blks_per_lun; j++) {
1188                         struct rrpc_block *rblk = &rlun->blocks[j];
1189                         struct nvm_block *blk = &lun->blocks[j];
1190
1191                         rblk->parent = blk;
1192                         rblk->rlun = rlun;
1193                         INIT_LIST_HEAD(&rblk->prio);
1194                         spin_lock_init(&rblk->lock);
1195                 }
1196         }
1197
1198         return 0;
1199 err:
1200         return -ENOMEM;
1201 }
1202
1203 static void rrpc_free(struct rrpc *rrpc)
1204 {
1205         rrpc_gc_free(rrpc);
1206         rrpc_map_free(rrpc);
1207         rrpc_core_free(rrpc);
1208         rrpc_luns_free(rrpc);
1209
1210         kfree(rrpc);
1211 }
1212
1213 static void rrpc_exit(void *private)
1214 {
1215         struct rrpc *rrpc = private;
1216
1217         del_timer(&rrpc->gc_timer);
1218
1219         flush_workqueue(rrpc->krqd_wq);
1220         flush_workqueue(rrpc->kgc_wq);
1221
1222         rrpc_free(rrpc);
1223 }
1224
1225 static sector_t rrpc_capacity(void *private)
1226 {
1227         struct rrpc *rrpc = private;
1228         struct nvm_dev *dev = rrpc->dev;
1229         sector_t reserved, provisioned;
1230
1231         /* cur, gc, and two emergency blocks for each lun */
1232         reserved = rrpc->nr_luns * dev->max_pages_per_blk * 4;
1233         provisioned = rrpc->nr_sects - reserved;
1234
1235         if (reserved > rrpc->nr_sects) {
1236                 pr_err("rrpc: not enough space available to expose storage.\n");
1237                 return 0;
1238         }
1239
1240         sector_div(provisioned, 10);
1241         return provisioned * 9 * NR_PHY_IN_LOG;
1242 }
1243
1244 /*
1245  * Looks up the logical address from reverse trans map and check if its valid by
1246  * comparing the logical to physical address with the physical address.
1247  * Returns 0 on free, otherwise 1 if in use
1248  */
1249 static void rrpc_block_map_update(struct rrpc *rrpc, struct rrpc_block *rblk)
1250 {
1251         struct nvm_dev *dev = rrpc->dev;
1252         int offset;
1253         struct rrpc_addr *laddr;
1254         u64 bpaddr, paddr, pladdr;
1255
1256         bpaddr = block_to_rel_addr(rrpc, rblk);
1257         for (offset = 0; offset < dev->sec_per_blk; offset++) {
1258                 paddr = bpaddr + offset;
1259
1260                 pladdr = rrpc->rev_trans_map[paddr].addr;
1261                 if (pladdr == ADDR_EMPTY)
1262                         continue;
1263
1264                 laddr = &rrpc->trans_map[pladdr];
1265
1266                 if (paddr == laddr->addr) {
1267                         laddr->rblk = rblk;
1268                 } else {
1269                         set_bit(offset, rblk->invalid_pages);
1270                         rblk->nr_invalid_pages++;
1271                 }
1272         }
1273 }
1274
1275 static int rrpc_blocks_init(struct rrpc *rrpc)
1276 {
1277         struct rrpc_lun *rlun;
1278         struct rrpc_block *rblk;
1279         int lun_iter, blk_iter;
1280
1281         for (lun_iter = 0; lun_iter < rrpc->nr_luns; lun_iter++) {
1282                 rlun = &rrpc->luns[lun_iter];
1283
1284                 for (blk_iter = 0; blk_iter < rrpc->dev->blks_per_lun;
1285                                                                 blk_iter++) {
1286                         rblk = &rlun->blocks[blk_iter];
1287                         rrpc_block_map_update(rrpc, rblk);
1288                 }
1289         }
1290
1291         return 0;
1292 }
1293
1294 static int rrpc_luns_configure(struct rrpc *rrpc)
1295 {
1296         struct rrpc_lun *rlun;
1297         struct rrpc_block *rblk;
1298         int i;
1299
1300         for (i = 0; i < rrpc->nr_luns; i++) {
1301                 rlun = &rrpc->luns[i];
1302
1303                 rblk = rrpc_get_blk(rrpc, rlun, 0);
1304                 if (!rblk)
1305                         goto err;
1306
1307                 rrpc_set_lun_cur(rlun, rblk);
1308
1309                 /* Emergency gc block */
1310                 rblk = rrpc_get_blk(rrpc, rlun, 1);
1311                 if (!rblk)
1312                         goto err;
1313                 rlun->gc_cur = rblk;
1314         }
1315
1316         return 0;
1317 err:
1318         rrpc_put_blks(rrpc);
1319         return -EINVAL;
1320 }
1321
1322 static struct nvm_tgt_type tt_rrpc;
1323
1324 static void *rrpc_init(struct nvm_dev *dev, struct gendisk *tdisk,
1325                                                 int lun_begin, int lun_end)
1326 {
1327         struct request_queue *bqueue = dev->q;
1328         struct request_queue *tqueue = tdisk->queue;
1329         struct rrpc *rrpc;
1330         int ret;
1331
1332         if (!(dev->identity.dom & NVM_RSP_L2P)) {
1333                 pr_err("nvm: rrpc: device does not support l2p (%x)\n",
1334                                                         dev->identity.dom);
1335                 return ERR_PTR(-EINVAL);
1336         }
1337
1338         rrpc = kzalloc(sizeof(struct rrpc), GFP_KERNEL);
1339         if (!rrpc)
1340                 return ERR_PTR(-ENOMEM);
1341
1342         rrpc->instance.tt = &tt_rrpc;
1343         rrpc->dev = dev;
1344         rrpc->disk = tdisk;
1345
1346         bio_list_init(&rrpc->requeue_bios);
1347         spin_lock_init(&rrpc->bio_lock);
1348         INIT_WORK(&rrpc->ws_requeue, rrpc_requeue);
1349
1350         rrpc->nr_luns = lun_end - lun_begin + 1;
1351
1352         /* simple round-robin strategy */
1353         atomic_set(&rrpc->next_lun, -1);
1354
1355         ret = rrpc_luns_init(rrpc, lun_begin, lun_end);
1356         if (ret) {
1357                 pr_err("nvm: rrpc: could not initialize luns\n");
1358                 goto err;
1359         }
1360
1361         rrpc->poffset = dev->sec_per_lun * lun_begin;
1362         rrpc->lun_offset = lun_begin;
1363
1364         ret = rrpc_core_init(rrpc);
1365         if (ret) {
1366                 pr_err("nvm: rrpc: could not initialize core\n");
1367                 goto err;
1368         }
1369
1370         ret = rrpc_map_init(rrpc);
1371         if (ret) {
1372                 pr_err("nvm: rrpc: could not initialize maps\n");
1373                 goto err;
1374         }
1375
1376         ret = rrpc_blocks_init(rrpc);
1377         if (ret) {
1378                 pr_err("nvm: rrpc: could not initialize state for blocks\n");
1379                 goto err;
1380         }
1381
1382         ret = rrpc_luns_configure(rrpc);
1383         if (ret) {
1384                 pr_err("nvm: rrpc: not enough blocks available in LUNs.\n");
1385                 goto err;
1386         }
1387
1388         ret = rrpc_gc_init(rrpc);
1389         if (ret) {
1390                 pr_err("nvm: rrpc: could not initialize gc\n");
1391                 goto err;
1392         }
1393
1394         /* inherit the size from the underlying device */
1395         blk_queue_logical_block_size(tqueue, queue_physical_block_size(bqueue));
1396         blk_queue_max_hw_sectors(tqueue, queue_max_hw_sectors(bqueue));
1397
1398         pr_info("nvm: rrpc initialized with %u luns and %llu pages.\n",
1399                         rrpc->nr_luns, (unsigned long long)rrpc->nr_sects);
1400
1401         mod_timer(&rrpc->gc_timer, jiffies + msecs_to_jiffies(10));
1402
1403         return rrpc;
1404 err:
1405         rrpc_free(rrpc);
1406         return ERR_PTR(ret);
1407 }
1408
1409 /* round robin, page-based FTL, and cost-based GC */
1410 static struct nvm_tgt_type tt_rrpc = {
1411         .name           = "rrpc",
1412         .version        = {1, 0, 0},
1413
1414         .make_rq        = rrpc_make_rq,
1415         .capacity       = rrpc_capacity,
1416         .end_io         = rrpc_end_io,
1417
1418         .init           = rrpc_init,
1419         .exit           = rrpc_exit,
1420 };
1421
1422 static int __init rrpc_module_init(void)
1423 {
1424         return nvm_register_target(&tt_rrpc);
1425 }
1426
1427 static void rrpc_module_exit(void)
1428 {
1429         nvm_unregister_target(&tt_rrpc);
1430 }
1431
1432 module_init(rrpc_module_init);
1433 module_exit(rrpc_module_exit);
1434 MODULE_LICENSE("GPL v2");
1435 MODULE_DESCRIPTION("Block-Device Target for Open-Channel SSDs");