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Matias Bjørlingae1519e2015-10-28 19:54:57 +01001/*
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
38struct rrpc_inflight {
39 struct list_head reqs;
40 spinlock_t lock;
41};
42
43struct rrpc_inflight_rq {
44 struct list_head list;
45 sector_t l_start;
46 sector_t l_end;
47};
48
49struct rrpc_rq {
50 struct rrpc_inflight_rq inflight_rq;
51 struct rrpc_addr *addr;
52 unsigned long flags;
53};
54
55struct 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
71struct 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
82struct 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
Matias Bjørlingb7ceb7d2015-11-02 17:12:27 +010089 u64 poffset; /* physical page offset */
Matias Bjørlingae1519e2015-10-28 19:54:57 +010090 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
131struct 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 */
138struct rrpc_addr {
Matias Bjørlingb7ceb7d2015-11-02 17:12:27 +0100139 u64 addr;
Matias Bjørlingae1519e2015-10-28 19:54:57 +0100140 struct rrpc_block *rblk;
141};
142
143/* Physical to logical mapping */
144struct rrpc_rev_addr {
Matias Bjørlingb7ceb7d2015-11-02 17:12:27 +0100145 u64 addr;
Matias Bjørlingae1519e2015-10-28 19:54:57 +0100146};
147
148static inline sector_t rrpc_get_laddr(struct bio *bio)
149{
150 return bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
151}
152
153static inline unsigned int rrpc_get_pages(struct bio *bio)
154{
155 return bio->bi_iter.bi_size / RRPC_EXPOSED_PAGE_SIZE;
156}
157
158static inline sector_t rrpc_get_sector(sector_t laddr)
159{
160 return laddr * NR_PHY_IN_LOG;
161}
162
163static 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
170static 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
193static 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
202static 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
209static 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
219static 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
229static 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_ */