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         struct nvm_lun *parent;
  78
  79         struct rrpc_block *cur, *gc_cur;
  80         struct rrpc_block *blocks;      /* Reference to block allocation */
  81
  82         struct list_head prio_list;     /* Blocks that may be GC'ed */
  83         struct list_head wblk_list;     /* Queued blocks to be written to */
  84
  85         /* lun block lists */
  86         struct list_head used_list;     /* In-use blocks */
  87         struct list_head free_list;     /* Not used blocks i.e. released
  88                                          * and ready for use
  89                                          */
  90         struct list_head bb_list;       /* Bad blocks. Mutually exclusive with
  91                                          * free_list and used_list
  92                                          */
  93         unsigned int nr_free_blocks;    /* Number of unused blocks */
  94
  95         struct work_struct ws_gc;
  96
  97         int reserved_blocks;
  98
  99         spinlock_t lock;
 100 };
 101
 102 struct rrpc {
 103         /* instance must be kept in top to resolve rrpc in unprep */
 104         struct nvm_tgt_instance instance;
 105
 106         struct nvm_tgt_dev *dev;
 107         struct gendisk *disk;
 108
 109         sector_t soffset; /* logical sector offset */
 110         u64 poffset; /* physical page offset */
 111
 112         int nr_luns;
 113         struct rrpc_lun *luns;
 114
 115         /* calculated values */
 116         unsigned long long nr_sects;
 117
 118         /* Write strategy variables. Move these into each for structure for each
 119          * strategy
 120          */
 121         atomic_t next_lun; /* Whenever a page is written, this is updated
 122                             * to point to the next write lun
 123                             */
 124
 125         spinlock_t bio_lock;
 126         struct bio_list requeue_bios;
 127         struct work_struct ws_requeue;
 128
 129         /* Simple translation map of logical addresses to physical addresses.
 130          * The logical addresses is known by the host system, while the physical
 131          * addresses are used when writing to the disk block device.
 132          */
 133         struct rrpc_addr *trans_map;
 134         /* also store a reverse map for garbage collection */
 135         struct rrpc_rev_addr *rev_trans_map;
 136         spinlock_t rev_lock;
 137
 138         struct rrpc_inflight inflights;
 139
 140         mempool_t *addr_pool;
 141         mempool_t *page_pool;
 142         mempool_t *gcb_pool;
 143         mempool_t *rq_pool;
 144
 145         struct timer_list gc_timer;
 146         struct workqueue_struct *krqd_wq;
 147         struct workqueue_struct *kgc_wq;
 148 };
 149
 150 struct rrpc_block_gc {
 151         struct rrpc *rrpc;
 152         struct rrpc_block *rblk;
 153         struct work_struct ws_gc;
 154 };
 155
 156 /* Logical to physical mapping */
 157 struct rrpc_addr {
 158         u64 addr;
 159         struct rrpc_block *rblk;
 160 };
 161
 162 /* Physical to logical mapping */
 163 struct rrpc_rev_addr {
 164         u64 addr;
 165 };
 166
 167 static inline u64 rrpc_blk_to_ppa(struct rrpc *rrpc, struct rrpc_block *rblk)
 168 {
 169         struct nvm_tgt_dev *dev = rrpc->dev;
 170         struct nvm_geo *geo = &dev->geo;
 171         struct rrpc_lun *rlun = rblk->rlun;
 172         struct nvm_lun *lun = rlun->parent;
 173
 174         return (lun->id * geo->sec_per_lun) + (rblk->id * geo->sec_per_blk);
 175 }
 176
 177 static inline sector_t rrpc_get_laddr(struct bio *bio)
 178 {
 179         return bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
 180 }
 181
 182 static inline unsigned int rrpc_get_pages(struct bio *bio)
 183 {
 184         return  bio->bi_iter.bi_size / RRPC_EXPOSED_PAGE_SIZE;
 185 }
 186
 187 static inline sector_t rrpc_get_sector(sector_t laddr)
 188 {
 189         return laddr * NR_PHY_IN_LOG;
 190 }
 191
 192 static inline int request_intersects(struct rrpc_inflight_rq *r,
 193                                 sector_t laddr_start, sector_t laddr_end)
 194 {
 195         return (laddr_end >= r->l_start) && (laddr_start <= r->l_end);
 196 }
 197
 198 static int __rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
 199                              unsigned int pages, struct rrpc_inflight_rq *r)
 200 {
 201         sector_t laddr_end = laddr + pages - 1;
 202         struct rrpc_inflight_rq *rtmp;
 203
 204         WARN_ON(irqs_disabled());
 205
 206         spin_lock_irq(&rrpc->inflights.lock);
 207         list_for_each_entry(rtmp, &rrpc->inflights.reqs, list) {
 208                 if (unlikely(request_intersects(rtmp, laddr, laddr_end))) {
 209                         /* existing, overlapping request, come back later */
 210                         spin_unlock_irq(&rrpc->inflights.lock);
 211                         return 1;
 212                 }
 213         }
 214
 215         r->l_start = laddr;
 216         r->l_end = laddr_end;
 217
 218         list_add_tail(&r->list, &rrpc->inflights.reqs);
 219         spin_unlock_irq(&rrpc->inflights.lock);
 220         return 0;
 221 }
 222
 223 static inline int rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
 224                                  unsigned int pages,
 225                                  struct rrpc_inflight_rq *r)
 226 {
 227         BUG_ON((laddr + pages) > rrpc->nr_sects);
 228
 229         return __rrpc_lock_laddr(rrpc, laddr, pages, r);
 230 }
 231
 232 static inline struct rrpc_inflight_rq *rrpc_get_inflight_rq(struct nvm_rq *rqd)
 233 {
 234         struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
 235
 236         return &rrqd->inflight_rq;
 237 }
 238
 239 static inline int rrpc_lock_rq(struct rrpc *rrpc, struct bio *bio,
 240                                                         struct nvm_rq *rqd)
 241 {
 242         sector_t laddr = rrpc_get_laddr(bio);
 243         unsigned int pages = rrpc_get_pages(bio);
 244         struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
 245
 246         return rrpc_lock_laddr(rrpc, laddr, pages, r);
 247 }
 248
 249 static inline void rrpc_unlock_laddr(struct rrpc *rrpc,
 250                                                 struct rrpc_inflight_rq *r)
 251 {
 252         unsigned long flags;
 253
 254         spin_lock_irqsave(&rrpc->inflights.lock, flags);
 255         list_del_init(&r->list);
 256         spin_unlock_irqrestore(&rrpc->inflights.lock, flags);
 257 }
 258
 259 static inline void rrpc_unlock_rq(struct rrpc *rrpc, struct nvm_rq *rqd)
 260 {
 261         struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
 262         uint8_t pages = rqd->nr_ppas;
 263
 264         BUG_ON((r->l_start + pages) > rrpc->nr_sects);
 265
 266         rrpc_unlock_laddr(rrpc, r);
 267 }
 268
 269 #endif /* RRPC_H_ */