/*
* Copyright (C) 2015 IT University of Copenhagen
* Initial release: Matias Bjorling <m@bjorling.me>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* Implementation of a Round-robin page-based Hybrid FTL for Open-channel SSDs.
*/
#ifndef RRPC_H_
#define RRPC_H_
#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/bio.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/vmalloc.h>
#include <linux/lightnvm.h>
/* Run only GC if less than 1/X blocks are free */
#define GC_LIMIT_INVERSE 10
#define GC_TIME_SECS 100
#define RRPC_SECTOR (512)
#define RRPC_EXPOSED_PAGE_SIZE (4096)
#define NR_PHY_IN_LOG (RRPC_EXPOSED_PAGE_SIZE / RRPC_SECTOR)
struct rrpc_inflight {
struct list_head reqs;
spinlock_t lock;
};
struct rrpc_inflight_rq {
struct list_head list;
sector_t l_start;
sector_t l_end;
};
struct rrpc_rq {
struct rrpc_inflight_rq inflight_rq;
unsigned long flags;
};
struct rrpc_block {
int id; /* id inside of LUN */
struct rrpc_lun *rlun;
struct list_head prio; /* LUN CG list */
struct list_head list; /* LUN free, used, bb list */
#define MAX_INVALID_PAGES_STORAGE 8
/* Bitmap for invalid page intries */
unsigned long invalid_pages[MAX_INVALID_PAGES_STORAGE];
/* points to the next writable page within a block */
unsigned int next_page;
/* number of pages that are invalid, wrt host page size */
unsigned int nr_invalid_pages;
int state;
spinlock_t lock;
atomic_t data_cmnt_size; /* data pages committed to stable storage */
};
struct rrpc_lun {
struct rrpc *rrpc;
int id;
struct ppa_addr bppa;
struct rrpc_block *cur, *gc_cur;
struct rrpc_block *blocks; /* Reference to block allocation */
struct list_head prio_list; /* Blocks that may be GC'ed */
struct list_head wblk_list; /* Queued blocks to be written to */
/* lun block lists */
struct list_head used_list; /* In-use blocks */
struct list_head free_list; /* Not used blocks i.e. released
* and ready for use
*/
struct list_head bb_list; /* Bad blocks. Mutually exclusive with
* free_list and used_list
*/
unsigned int nr_free_blocks; /* Number of unused blocks */
struct work_struct ws_gc;
int reserved_blocks;
spinlock_t lock;
};
struct rrpc {
struct nvm_tgt_dev *dev;
struct gendisk *disk;
sector_t soffset; /* logical sector offset */
int nr_luns;
struct rrpc_lun *luns;
/* calculated values */
unsigned long long nr_sects;
/* Write strategy variables. Move these into each for structure for each
* strategy
*/
atomic_t next_lun; /* Whenever a page is written, this is updated
* to point to the next write lun
*/
spinlock_t bio_lock;
struct bio_list requeue_bios;
struct work_struct ws_requeue;
/* Simple translation map of logical addresses to physical addresses.
* The logical addresses is known by the host system, while the physical
* addresses are used when writing to the disk block device.
*/
struct rrpc_addr *trans_map;
/* also store a reverse map for garbage collection */
struct rrpc_rev_addr *rev_trans_map;
spinlock_t rev_lock;
struct rrpc_inflight inflights;
mempool_t *addr_pool;
mempool_t *page_pool;
mempool_t *gcb_pool;
mempool_t *rq_pool;
struct timer_list gc_timer;
struct workqueue_struct *krqd_wq;
struct workqueue_struct *kgc_wq;
};
struct rrpc_block_gc {
struct rrpc *rrpc;
struct rrpc_block *rblk;
struct work_struct ws_gc;
};
/* Logical to physical mapping */
struct rrpc_addr {
u64 addr;
struct rrpc_block *rblk;
};
/* Physical to logical mapping */
struct rrpc_rev_addr {
u64 addr;
};
static inline struct ppa_addr rrpc_linear_to_generic_addr(struct nvm_geo *geo,
struct ppa_addr r)
{
struct ppa_addr l;
int secs, pgs;
sector_t ppa = r.ppa;
l.ppa = 0;
div_u64_rem(ppa, geo->sec_per_pg, &secs);
l.g.sec = secs;
sector_div(ppa, geo->sec_per_pg);
div_u64_rem(ppa, geo->pgs_per_blk, &pgs);
l.g.pg = pgs;
return l;
}
static inline struct ppa_addr rrpc_recov_addr(struct nvm_tgt_dev *dev, u64 pba)
{
return linear_to_generic_addr(&dev->geo, pba);
}
static inline u64 rrpc_blk_to_ppa(struct rrpc *rrpc, struct rrpc_block *rblk)
{
struct nvm_tgt_dev *dev = rrpc->dev;
struct nvm_geo *geo = &dev->geo;
struct rrpc_lun *rlun = rblk->rlun;
return (rlun->id * geo->sec_per_lun) + (rblk->id * geo->sec_per_blk);
}
static inline sector_t rrpc_get_laddr(struct bio *bio)
{
return bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
}
static inline unsigned int rrpc_get_pages(struct bio *bio)
{
return bio->bi_iter.bi_size / RRPC_EXPOSED_PAGE_SIZE;
}
static inline sector_t rrpc_get_sector(sector_t laddr)
{
return laddr * NR_PHY_IN_LOG;
}
static inline int request_intersects(struct rrpc_inflight_rq *r,
sector_t laddr_start, sector_t laddr_end)
{
return (laddr_end >= r->l_start) && (laddr_start <= r->l_end);
}
static int __rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
unsigned int pages, struct rrpc_inflight_rq *r)
{
sector_t laddr_end = laddr + pages - 1;
struct rrpc_inflight_rq *rtmp;
WARN_ON(irqs_disabled());
spin_lock_irq(&rrpc->inflights.lock);
list_for_each_entry(rtmp, &rrpc->inflights.reqs, list) {
if (unlikely(request_intersects(rtmp, laddr, laddr_end))) {
/* existing, overlapping request, come back later */
spin_unlock_irq(&rrpc->inflights.lock);
return 1;
}
}
r->l_start = laddr;
r->l_end = laddr_end;
list_add_tail(&r->list, &rrpc->inflights.reqs);
spin_unlock_irq(&rrpc->inflights.lock);
return 0;
}
static inline int rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
unsigned int pages,
struct rrpc_inflight_rq *r)
{
BUG_ON((laddr + pages) > rrpc->nr_sects);
return __rrpc_lock_laddr(rrpc, laddr, pages, r);
}
static inline struct rrpc_inflight_rq *rrpc_get_inflight_rq(struct nvm_rq *rqd)
{
struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
return &rrqd->inflight_rq;
}
static inline int rrpc_lock_rq(struct rrpc *rrpc, struct bio *bio,
struct nvm_rq *rqd)
{
sector_t laddr = rrpc_get_laddr(bio);
unsigned int pages = rrpc_get_pages(bio);
struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
return rrpc_lock_laddr(rrpc, laddr, pages, r);
}
static inline void rrpc_unlock_laddr(struct rrpc *rrpc,
struct rrpc_inflight_rq *r)
{
unsigned long flags;
spin_lock_irqsave(&rrpc->inflights.lock, flags);
list_del_init(&r->list);
spin_unlock_irqrestore(&rrpc->inflights.lock, flags);
}
static inline void rrpc_unlock_rq(struct rrpc *rrpc, struct nvm_rq *rqd)
{
struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
uint8_t pages = rqd->nr_ppas;
BUG_ON((r->l_start + pages) > rrpc->nr_sects);
rrpc_unlock_laddr(rrpc, r);
}
#endif /* RRPC_H_ */
