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         sector_t soffset; /* logical sector offset */
 101         u64 poffset; /* physical page offset */
 102         int lun_offset;
 103
 104         int nr_luns;
 105         struct rrpc_lun *luns;
 106
 107         /* calculated values */
 108         unsigned long long nr_sects;
 109         unsigned long total_blocks;
 110
 111         /* Write strategy variables. Move these into each for structure for each
 112          * strategy
 113          */
 114         atomic_t next_lun; /* Whenever a page is written, this is updated
 115                             * to point to the next write lun
 116                             */
 117
 118         spinlock_t bio_lock;
 119         struct bio_list requeue_bios;
 120         struct work_struct ws_requeue;
 121
 122         /* Simple translation map of logical addresses to physical addresses.
 123          * The logical addresses is known by the host system, while the physical
 124          * addresses are used when writing to the disk block device.
 125          */
 126         struct rrpc_addr *trans_map;
 127         /* also store a reverse map for garbage collection */
 128         struct rrpc_rev_addr *rev_trans_map;
 129         spinlock_t rev_lock;
 130
 131         struct rrpc_inflight inflights;
 132
 133         mempool_t *addr_pool;
 134         mempool_t *page_pool;
 135         mempool_t *gcb_pool;
 136         mempool_t *rq_pool;
 137
 138         struct timer_list gc_timer;
 139         struct workqueue_struct *krqd_wq;
 140         struct workqueue_struct *kgc_wq;
 141 };
 142
 143 struct rrpc_block_gc {
 144         struct rrpc *rrpc;
 145         struct rrpc_block *rblk;
 146         struct work_struct ws_gc;
 147 };
 148
 149 /* Logical to physical mapping */
 150 struct rrpc_addr {
 151         u64 addr;
 152         struct rrpc_block *rblk;
 153 };
 154
 155 /* Physical to logical mapping */
 156 struct rrpc_rev_addr {
 157         u64 addr;
 158 };
 159
 160 static inline struct rrpc_block *rrpc_get_rblk(struct rrpc_lun *rlun,
 161                                                                 int blk_id)
 162 {
 163         struct rrpc *rrpc = rlun->rrpc;
 164         int lun_blk = blk_id % rrpc->dev->blks_per_lun;
 165
 166         return &rlun->blocks[lun_blk];
 167 }
 168
 169 static inline sector_t rrpc_get_laddr(struct bio *bio)
 170 {
 171         return bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
 172 }
 173
 174 static inline unsigned int rrpc_get_pages(struct bio *bio)
 175 {
 176         return  bio->bi_iter.bi_size / RRPC_EXPOSED_PAGE_SIZE;
 177 }
 178
 179 static inline sector_t rrpc_get_sector(sector_t laddr)
 180 {
 181         return laddr * NR_PHY_IN_LOG;
 182 }
 183
 184 static inline int request_intersects(struct rrpc_inflight_rq *r,
 185                                 sector_t laddr_start, sector_t laddr_end)
 186 {
 187         return (laddr_end >= r->l_start) && (laddr_start <= r->l_end);
 188 }
 189
 190 static int __rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
 191                              unsigned pages, struct rrpc_inflight_rq *r)
 192 {
 193         sector_t laddr_end = laddr + pages - 1;
 194         struct rrpc_inflight_rq *rtmp;
 195
 196         WARN_ON(irqs_disabled());
 197
 198         spin_lock_irq(&rrpc->inflights.lock);
 199         list_for_each_entry(rtmp, &rrpc->inflights.reqs, list) {
 200                 if (unlikely(request_intersects(rtmp, laddr, laddr_end))) {
 201                         /* existing, overlapping request, come back later */
 202                         spin_unlock_irq(&rrpc->inflights.lock);
 203                         return 1;
 204                 }
 205         }
 206
 207         r->l_start = laddr;
 208         r->l_end = laddr_end;
 209
 210         list_add_tail(&r->list, &rrpc->inflights.reqs);
 211         spin_unlock_irq(&rrpc->inflights.lock);
 212         return 0;
 213 }
 214
 215 static inline int rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
 216                                  unsigned pages,
 217                                  struct rrpc_inflight_rq *r)
 218 {
 219         BUG_ON((laddr + pages) > rrpc->nr_sects);
 220
 221         return __rrpc_lock_laddr(rrpc, laddr, pages, r);
 222 }
 223
 224 static inline struct rrpc_inflight_rq *rrpc_get_inflight_rq(struct nvm_rq *rqd)
 225 {
 226         struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
 227
 228         return &rrqd->inflight_rq;
 229 }
 230
 231 static inline int rrpc_lock_rq(struct rrpc *rrpc, struct bio *bio,
 232                                                         struct nvm_rq *rqd)
 233 {
 234         sector_t laddr = rrpc_get_laddr(bio);
 235         unsigned int pages = rrpc_get_pages(bio);
 236         struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
 237
 238         return rrpc_lock_laddr(rrpc, laddr, pages, r);
 239 }
 240
 241 static inline void rrpc_unlock_laddr(struct rrpc *rrpc,
 242                                                 struct rrpc_inflight_rq *r)
 243 {
 244         unsigned long flags;
 245
 246         spin_lock_irqsave(&rrpc->inflights.lock, flags);
 247         list_del_init(&r->list);
 248         spin_unlock_irqrestore(&rrpc->inflights.lock, flags);
 249 }
 250
 251 static inline void rrpc_unlock_rq(struct rrpc *rrpc, struct nvm_rq *rqd)
 252 {
 253         struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
 254         uint8_t pages = rqd->nr_pages;
 255
 256         BUG_ON((r->l_start + pages) > rrpc->nr_sects);
 257
 258         rrpc_unlock_laddr(rrpc, r);
 259 }
 260
 261 #endif /* RRPC_H_ */