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         struct rrpc_addr *addr;
  52         unsigned long flags;
  53 };
  54
  55 struct rrpc_block {
  56         struct nvm_block *parent;
  57         struct rrpc_lun *rlun;
  58         struct list_head prio;
  59
  60 #define MAX_INVALID_PAGES_STORAGE 8
  61         /* Bitmap for invalid page intries */
  62         unsigned long invalid_pages[MAX_INVALID_PAGES_STORAGE];
  63         /* points to the next writable page within a block */
  64         unsigned int next_page;
  65         /* number of pages that are invalid, wrt host page size */
  66         unsigned int nr_invalid_pages;
  67
  68         spinlock_t lock;
  69         atomic_t data_cmnt_size; /* data pages committed to stable storage */
  70 };
  71
  72 struct rrpc_lun {
  73         struct rrpc *rrpc;
  74         struct nvm_lun *parent;
  75         struct rrpc_block *cur, *gc_cur;
  76         struct rrpc_block *blocks;      /* Reference to block allocation */
  77
  78         struct list_head prio_list;     /* Blocks that may be GC'ed */
  79         struct list_head wblk_list;     /* Queued blocks to be written to */
  80
  81         struct work_struct ws_gc;
  82
  83         spinlock_t lock;
  84 };
  85
  86 struct rrpc {
  87         /* instance must be kept in top to resolve rrpc in unprep */
  88         struct nvm_tgt_instance instance;
  89
  90         struct nvm_dev *dev;
  91         struct gendisk *disk;
  92
  93         sector_t soffset; /* logical sector offset */
  94         u64 poffset; /* physical page offset */
  95         int lun_offset;
  96
  97         int nr_luns;
  98         struct rrpc_lun *luns;
  99
 100         /* calculated values */
 101         unsigned long long nr_sects;
 102         unsigned long total_blocks;
 103
 104         /* Write strategy variables. Move these into each for structure for each
 105          * strategy
 106          */
 107         atomic_t next_lun; /* Whenever a page is written, this is updated
 108                             * to point to the next write lun
 109                             */
 110
 111         spinlock_t bio_lock;
 112         struct bio_list requeue_bios;
 113         struct work_struct ws_requeue;
 114
 115         /* Simple translation map of logical addresses to physical addresses.
 116          * The logical addresses is known by the host system, while the physical
 117          * addresses are used when writing to the disk block device.
 118          */
 119         struct rrpc_addr *trans_map;
 120         /* also store a reverse map for garbage collection */
 121         struct rrpc_rev_addr *rev_trans_map;
 122         spinlock_t rev_lock;
 123
 124         struct rrpc_inflight inflights;
 125
 126         mempool_t *addr_pool;
 127         mempool_t *page_pool;
 128         mempool_t *gcb_pool;
 129         mempool_t *rq_pool;
 130
 131         struct timer_list gc_timer;
 132         struct workqueue_struct *krqd_wq;
 133         struct workqueue_struct *kgc_wq;
 134 };
 135
 136 struct rrpc_block_gc {
 137         struct rrpc *rrpc;
 138         struct rrpc_block *rblk;
 139         struct work_struct ws_gc;
 140 };
 141
 142 /* Logical to physical mapping */
 143 struct rrpc_addr {
 144         u64 addr;
 145         struct rrpc_block *rblk;
 146 };
 147
 148 /* Physical to logical mapping */
 149 struct rrpc_rev_addr {
 150         u64 addr;
 151 };
 152
 153 static inline struct rrpc_block *rrpc_get_rblk(struct rrpc_lun *rlun,
 154                                                                 int blk_id)
 155 {
 156         struct rrpc *rrpc = rlun->rrpc;
 157         int lun_blk = blk_id % rrpc->dev->blks_per_lun;
 158
 159         return &rlun->blocks[lun_blk];
 160 }
 161
 162 static inline sector_t rrpc_get_laddr(struct bio *bio)
 163 {
 164         return bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
 165 }
 166
 167 static inline unsigned int rrpc_get_pages(struct bio *bio)
 168 {
 169         return  bio->bi_iter.bi_size / RRPC_EXPOSED_PAGE_SIZE;
 170 }
 171
 172 static inline sector_t rrpc_get_sector(sector_t laddr)
 173 {
 174         return laddr * NR_PHY_IN_LOG;
 175 }
 176
 177 static inline int request_intersects(struct rrpc_inflight_rq *r,
 178                                 sector_t laddr_start, sector_t laddr_end)
 179 {
 180         return (laddr_end >= r->l_start) && (laddr_start <= r->l_end);
 181 }
 182
 183 static int __rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
 184                              unsigned int pages, struct rrpc_inflight_rq *r)
 185 {
 186         sector_t laddr_end = laddr + pages - 1;
 187         struct rrpc_inflight_rq *rtmp;
 188
 189         WARN_ON(irqs_disabled());
 190
 191         spin_lock_irq(&rrpc->inflights.lock);
 192         list_for_each_entry(rtmp, &rrpc->inflights.reqs, list) {
 193                 if (unlikely(request_intersects(rtmp, laddr, laddr_end))) {
 194                         /* existing, overlapping request, come back later */
 195                         spin_unlock_irq(&rrpc->inflights.lock);
 196                         return 1;
 197                 }
 198         }
 199
 200         r->l_start = laddr;
 201         r->l_end = laddr_end;
 202
 203         list_add_tail(&r->list, &rrpc->inflights.reqs);
 204         spin_unlock_irq(&rrpc->inflights.lock);
 205         return 0;
 206 }
 207
 208 static inline int rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
 209                                  unsigned int pages,
 210                                  struct rrpc_inflight_rq *r)
 211 {
 212         BUG_ON((laddr + pages) > rrpc->nr_sects);
 213
 214         return __rrpc_lock_laddr(rrpc, laddr, pages, r);
 215 }
 216
 217 static inline struct rrpc_inflight_rq *rrpc_get_inflight_rq(struct nvm_rq *rqd)
 218 {
 219         struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
 220
 221         return &rrqd->inflight_rq;
 222 }
 223
 224 static inline int rrpc_lock_rq(struct rrpc *rrpc, struct bio *bio,
 225                                                         struct nvm_rq *rqd)
 226 {
 227         sector_t laddr = rrpc_get_laddr(bio);
 228         unsigned int pages = rrpc_get_pages(bio);
 229         struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
 230
 231         return rrpc_lock_laddr(rrpc, laddr, pages, r);
 232 }
 233
 234 static inline void rrpc_unlock_laddr(struct rrpc *rrpc,
 235                                                 struct rrpc_inflight_rq *r)
 236 {
 237         unsigned long flags;
 238
 239         spin_lock_irqsave(&rrpc->inflights.lock, flags);
 240         list_del_init(&r->list);
 241         spin_unlock_irqrestore(&rrpc->inflights.lock, flags);
 242 }
 243
 244 static inline void rrpc_unlock_rq(struct rrpc *rrpc, struct nvm_rq *rqd)
 245 {
 246         struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
 247         uint8_t pages = rqd->nr_ppas;
 248
 249         BUG_ON((r->l_start + pages) > rrpc->nr_sects);
 250
 251         rrpc_unlock_laddr(rrpc, r);
 252 }
 253
 254 #endif /* RRPC_H_ */