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