drivers/lightnvm/rrpc.h

   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 #ifndef RRPC_H_
  18 #define RRPC_H_
  19
  20 #include <linux/blkdev.h>
  21 #include <linux/blk-mq.h>
  22 #include <linux/bio.h>
  23 #include <linux/module.h>
  24 #include <linux/kthread.h>
  25 #include <linux/vmalloc.h>
  26
  27 #include <linux/lightnvm.h>
  28
  29 /* Run only GC if less than 1/X blocks are free */
  30 #define GC_LIMIT_INVERSE 10
  31 #define GC_TIME_SECS 100
  32
  33 #define RRPC_SECTOR (512)
  34 #define RRPC_EXPOSED_PAGE_SIZE (4096)
  35
  36 #define NR_PHY_IN_LOG (RRPC_EXPOSED_PAGE_SIZE / RRPC_SECTOR)
  37
  38 struct rrpc_inflight {
  39         struct list_head reqs;
  40         spinlock_t lock;
  41 };
  42
  43 struct rrpc_inflight_rq {
  44         struct list_head list;
  45         sector_t l_start;
  46         sector_t l_end;
  47 };
  48
  49 struct rrpc_rq {
  50         struct rrpc_inflight_rq inflight_rq;
  51         unsigned long flags;
  52 };
  53
  54 struct rrpc_block {
  55         int id;                         /* id inside of LUN */
  56         struct rrpc_lun *rlun;
  57
  58         struct list_head prio;          /* LUN CG list */
  59         struct list_head list;          /* LUN free, used, bb list */
  60
  61 #define MAX_INVALID_PAGES_STORAGE 8
  62         /* Bitmap for invalid page intries */
  63         unsigned long invalid_pages[MAX_INVALID_PAGES_STORAGE];
  64         /* points to the next writable page within a block */
  65         unsigned int next_page;
  66         /* number of pages that are invalid, wrt host page size */
  67         unsigned int nr_invalid_pages;
  68
  69         int state;
  70
  71         spinlock_t lock;
  72         atomic_t data_cmnt_size; /* data pages committed to stable storage */
  73 };
  74
  75 struct rrpc_lun {
  76         struct rrpc *rrpc;
  77
  78         int id;
  79         struct ppa_addr bppa;
  80
  81         struct rrpc_block *cur, *gc_cur;
  82         struct rrpc_block *blocks;      /* Reference to block allocation */
  83
  84         struct list_head prio_list;     /* Blocks that may be GC'ed */
  85         struct list_head wblk_list;     /* Queued blocks to be written to */
  86
  87         /* lun block lists */
  88         struct list_head used_list;     /* In-use blocks */
  89         struct list_head free_list;     /* Not used blocks i.e. released
  90                                          * and ready for use
  91                                          */
  92         struct list_head bb_list;       /* Bad blocks. Mutually exclusive with
  93                                          * free_list and used_list
  94                                          */
  95         unsigned int nr_free_blocks;    /* Number of unused blocks */
  96
  97         struct work_struct ws_gc;
  98
  99         int reserved_blocks;
 100
 101         spinlock_t lock;
 102 };
 103
 104 struct rrpc {
 105         struct nvm_tgt_dev *dev;
 106         struct gendisk *disk;
 107
 108         sector_t soffset; /* logical sector offset */
 109
 110         int nr_luns;
 111         struct rrpc_lun *luns;
 112
 113         /* calculated values */
 114         unsigned long long nr_sects;
 115
 116         /* Write strategy variables. Move these into each for structure for each
 117          * strategy
 118          */
 119         atomic_t next_lun; /* Whenever a page is written, this is updated
 120                             * to point to the next write lun
 121                             */
 122
 123         spinlock_t bio_lock;
 124         struct bio_list requeue_bios;
 125         struct work_struct ws_requeue;
 126
 127         /* Simple translation map of logical addresses to physical addresses.
 128          * The logical addresses is known by the host system, while the physical
 129          * addresses are used when writing to the disk block device.
 130          */
 131         struct rrpc_addr *trans_map;
 132         /* also store a reverse map for garbage collection */
 133         struct rrpc_rev_addr *rev_trans_map;
 134         spinlock_t rev_lock;
 135
 136         struct rrpc_inflight inflights;
 137
 138         mempool_t *addr_pool;
 139         mempool_t *page_pool;
 140         mempool_t *gcb_pool;
 141         mempool_t *rq_pool;
 142
 143         struct timer_list gc_timer;
 144         struct workqueue_struct *krqd_wq;
 145         struct workqueue_struct *kgc_wq;
 146 };
 147
 148 struct rrpc_block_gc {
 149         struct rrpc *rrpc;
 150         struct rrpc_block *rblk;
 151         struct work_struct ws_gc;
 152 };
 153
 154 /* Logical to physical mapping */
 155 struct rrpc_addr {
 156         u64 addr;
 157         struct rrpc_block *rblk;
 158 };
 159
 160 /* Physical to logical mapping */
 161 struct rrpc_rev_addr {
 162         u64 addr;
 163 };
 164
 165 static inline struct ppa_addr rrpc_linear_to_generic_addr(struct nvm_geo *geo,
 166                                                           struct ppa_addr r)
 167 {
 168         struct ppa_addr l;
 169         int secs, pgs;
 170         sector_t ppa = r.ppa;
 171
 172         l.ppa = 0;
 173
 174         div_u64_rem(ppa, geo->sec_per_pg, &secs);
 175         l.g.sec = secs;
 176
 177         sector_div(ppa, geo->sec_per_pg);
 178         div_u64_rem(ppa, geo->pgs_per_blk, &pgs);
 179         l.g.pg = pgs;
 180
 181         return l;
 182 }
 183
 184 static inline struct ppa_addr rrpc_recov_addr(struct nvm_tgt_dev *dev, u64 pba)
 185 {
 186         return linear_to_generic_addr(&dev->geo, pba);
 187 }
 188
 189 static inline u64 rrpc_blk_to_ppa(struct rrpc *rrpc, struct rrpc_block *rblk)
 190 {
 191         struct nvm_tgt_dev *dev = rrpc->dev;
 192         struct nvm_geo *geo = &dev->geo;
 193         struct rrpc_lun *rlun = rblk->rlun;
 194
 195         return (rlun->id * geo->sec_per_lun) + (rblk->id * geo->sec_per_blk);
 196 }
 197
 198 static inline sector_t rrpc_get_laddr(struct bio *bio)
 199 {
 200         return bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
 201 }
 202
 203 static inline unsigned int rrpc_get_pages(struct bio *bio)
 204 {
 205         return  bio->bi_iter.bi_size / RRPC_EXPOSED_PAGE_SIZE;
 206 }
 207
 208 static inline sector_t rrpc_get_sector(sector_t laddr)
 209 {
 210         return laddr * NR_PHY_IN_LOG;
 211 }
 212
 213 static inline int request_intersects(struct rrpc_inflight_rq *r,
 214                                 sector_t laddr_start, sector_t laddr_end)
 215 {
 216         return (laddr_end >= r->l_start) && (laddr_start <= r->l_end);
 217 }
 218
 219 static int __rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
 220                              unsigned int pages, struct rrpc_inflight_rq *r)
 221 {
 222         sector_t laddr_end = laddr + pages - 1;
 223         struct rrpc_inflight_rq *rtmp;
 224
 225         WARN_ON(irqs_disabled());
 226
 227         spin_lock_irq(&rrpc->inflights.lock);
 228         list_for_each_entry(rtmp, &rrpc->inflights.reqs, list) {
 229                 if (unlikely(request_intersects(rtmp, laddr, laddr_end))) {
 230                         /* existing, overlapping request, come back later */
 231                         spin_unlock_irq(&rrpc->inflights.lock);
 232                         return 1;
 233                 }
 234         }
 235
 236         r->l_start = laddr;
 237         r->l_end = laddr_end;
 238
 239         list_add_tail(&r->list, &rrpc->inflights.reqs);
 240         spin_unlock_irq(&rrpc->inflights.lock);
 241         return 0;
 242 }
 243
 244 static inline int rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
 245                                  unsigned int pages,
 246                                  struct rrpc_inflight_rq *r)
 247 {
 248         BUG_ON((laddr + pages) > rrpc->nr_sects);
 249
 250         return __rrpc_lock_laddr(rrpc, laddr, pages, r);
 251 }
 252
 253 static inline struct rrpc_inflight_rq *rrpc_get_inflight_rq(struct nvm_rq *rqd)
 254 {
 255         struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
 256
 257         return &rrqd->inflight_rq;
 258 }
 259
 260 static inline int rrpc_lock_rq(struct rrpc *rrpc, struct bio *bio,
 261                                                         struct nvm_rq *rqd)
 262 {
 263         sector_t laddr = rrpc_get_laddr(bio);
 264         unsigned int pages = rrpc_get_pages(bio);
 265         struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
 266
 267         return rrpc_lock_laddr(rrpc, laddr, pages, r);
 268 }
 269
 270 static inline void rrpc_unlock_laddr(struct rrpc *rrpc,
 271                                                 struct rrpc_inflight_rq *r)
 272 {
 273         unsigned long flags;
 274
 275         spin_lock_irqsave(&rrpc->inflights.lock, flags);
 276         list_del_init(&r->list);
 277         spin_unlock_irqrestore(&rrpc->inflights.lock, flags);
 278 }
 279
 280 static inline void rrpc_unlock_rq(struct rrpc *rrpc, struct nvm_rq *rqd)
 281 {
 282         struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
 283         uint8_t pages = rqd->nr_ppas;
 284
 285         BUG_ON((r->l_start + pages) > rrpc->nr_sects);
 286
 287         rrpc_unlock_laddr(rrpc, r);
 288 }
 289
 290 #endif /* RRPC_H_ */