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