/*
 * Copyright (C) 2016 CNEX Labs
 * Initial release: Javier Gonzalez <javier@cnexlabs.com>
 *                  Matias Bjorling <matias@cnexlabs.com>
 *
 * 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.
 *
 * pblk-core.c - pblk's core functionality
 *
 */

#include "pblk.h"

static void pblk_line_mark_bb(struct work_struct *work)
{
        struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
                                                                        ws);
        struct pblk *pblk = line_ws->pblk;
        struct nvm_tgt_dev *dev = pblk->dev;
        struct ppa_addr *ppa = line_ws->priv;
        int ret;

        ret = nvm_set_tgt_bb_tbl(dev, ppa, 1, NVM_BLK_T_GRWN_BAD);
        if (ret) {
                struct pblk_line *line;
                int pos;

                line = &pblk->lines[pblk_ppa_to_line(*ppa)];
                pos = pblk_ppa_to_pos(&dev->geo, *ppa);

                pr_err("pblk: failed to mark bb, line:%d, pos:%d\n",
                                line->id, pos);
        }

        kfree(ppa);
        mempool_free(line_ws, pblk->gen_ws_pool);
}

static void pblk_mark_bb(struct pblk *pblk, struct pblk_line *line,
                         struct ppa_addr ppa_addr)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct ppa_addr *ppa;
        int pos = pblk_ppa_to_pos(geo, ppa_addr);

        pr_debug("pblk: erase failed: line:%d, pos:%d\n", line->id, pos);
        atomic_long_inc(&pblk->erase_failed);

        atomic_dec(&line->blk_in_line);
        if (test_and_set_bit(pos, line->blk_bitmap))
                pr_err("pblk: attempted to erase bb: line:%d, pos:%d\n",
                                                        line->id, pos);

        /* Not necessary to mark bad blocks on 2.0 spec. */
        if (geo->version == NVM_OCSSD_SPEC_20)
                return;

        ppa = kmalloc(sizeof(struct ppa_addr), GFP_ATOMIC);
        if (!ppa)
                return;

        *ppa = ppa_addr;
        pblk_gen_run_ws(pblk, NULL, ppa, pblk_line_mark_bb,
                                                GFP_ATOMIC, pblk->bb_wq);
}

static void __pblk_end_io_erase(struct pblk *pblk, struct nvm_rq *rqd)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct nvm_chk_meta *chunk;
        struct pblk_line *line;
        int pos;

        line = &pblk->lines[pblk_ppa_to_line(rqd->ppa_addr)];
        pos = pblk_ppa_to_pos(geo, rqd->ppa_addr);
        chunk = &line->chks[pos];

        atomic_dec(&line->left_seblks);

        if (rqd->error) {
                chunk->state = NVM_CHK_ST_OFFLINE;
                pblk_mark_bb(pblk, line, rqd->ppa_addr);
        } else {
                chunk->state = NVM_CHK_ST_FREE;
        }

        atomic_dec(&pblk->inflight_io);
}

/* Erase completion assumes that only one block is erased at the time */
static void pblk_end_io_erase(struct nvm_rq *rqd)
{
        struct pblk *pblk = rqd->private;

        __pblk_end_io_erase(pblk, rqd);
        mempool_free(rqd, pblk->e_rq_pool);
}

/*
 * Get information for all chunks from the device.
 *
 * The caller is responsible for freeing the returned structure
 */
struct nvm_chk_meta *pblk_chunk_get_info(struct pblk *pblk)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct nvm_chk_meta *meta;
        struct ppa_addr ppa;
        unsigned long len;
        int ret;

        ppa.ppa = 0;

        len = geo->all_chunks * sizeof(*meta);
        meta = kzalloc(len, GFP_KERNEL);
        if (!meta)
                return ERR_PTR(-ENOMEM);

        ret = nvm_get_chunk_meta(dev, meta, ppa, geo->all_chunks);
        if (ret) {
                kfree(meta);
                return ERR_PTR(-EIO);
        }

        return meta;
}

struct nvm_chk_meta *pblk_chunk_get_off(struct pblk *pblk,
                                              struct nvm_chk_meta *meta,
                                              struct ppa_addr ppa)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        int ch_off = ppa.m.grp * geo->num_chk * geo->num_lun;
        int lun_off = ppa.m.pu * geo->num_chk;
        int chk_off = ppa.m.chk;

        return meta + ch_off + lun_off + chk_off;
}

void __pblk_map_invalidate(struct pblk *pblk, struct pblk_line *line,
                           u64 paddr)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct list_head *move_list = NULL;

        /* Lines being reclaimed (GC'ed) cannot be invalidated. Before the L2P
         * table is modified with reclaimed sectors, a check is done to endure
         * that newer updates are not overwritten.
         */
        spin_lock(&line->lock);
        WARN_ON(line->state == PBLK_LINESTATE_FREE);

        if (test_and_set_bit(paddr, line->invalid_bitmap)) {
                WARN_ONCE(1, "pblk: double invalidate\n");
                spin_unlock(&line->lock);
                return;
        }
        le32_add_cpu(line->vsc, -1);

        if (line->state == PBLK_LINESTATE_CLOSED)
                move_list = pblk_line_gc_list(pblk, line);
        spin_unlock(&line->lock);

        if (move_list) {
                spin_lock(&l_mg->gc_lock);
                spin_lock(&line->lock);
                /* Prevent moving a line that has just been chosen for GC */
                if (line->state == PBLK_LINESTATE_GC) {
                        spin_unlock(&line->lock);
                        spin_unlock(&l_mg->gc_lock);
                        return;
                }
                spin_unlock(&line->lock);

                list_move_tail(&line->list, move_list);
                spin_unlock(&l_mg->gc_lock);
        }
}

void pblk_map_invalidate(struct pblk *pblk, struct ppa_addr ppa)
{
        struct pblk_line *line;
        u64 paddr;
        int line_id;

#ifdef CONFIG_NVM_DEBUG
        /* Callers must ensure that the ppa points to a device address */
        BUG_ON(pblk_addr_in_cache(ppa));
        BUG_ON(pblk_ppa_empty(ppa));
#endif

        line_id = pblk_ppa_to_line(ppa);
        line = &pblk->lines[line_id];
        paddr = pblk_dev_ppa_to_line_addr(pblk, ppa);

        __pblk_map_invalidate(pblk, line, paddr);
}

static void pblk_invalidate_range(struct pblk *pblk, sector_t slba,
                                  unsigned int nr_secs)
{
        sector_t lba;

        spin_lock(&pblk->trans_lock);
        for (lba = slba; lba < slba + nr_secs; lba++) {
                struct ppa_addr ppa;

                ppa = pblk_trans_map_get(pblk, lba);

                if (!pblk_addr_in_cache(ppa) && !pblk_ppa_empty(ppa))
                        pblk_map_invalidate(pblk, ppa);

                pblk_ppa_set_empty(&ppa);
                pblk_trans_map_set(pblk, lba, ppa);
        }
        spin_unlock(&pblk->trans_lock);
}

/* Caller must guarantee that the request is a valid type */
struct nvm_rq *pblk_alloc_rqd(struct pblk *pblk, int type)
{
        mempool_t *pool;
        struct nvm_rq *rqd;
        int rq_size;

        switch (type) {
        case PBLK_WRITE:
        case PBLK_WRITE_INT:
                pool = pblk->w_rq_pool;
                rq_size = pblk_w_rq_size;
                break;
        case PBLK_READ:
                pool = pblk->r_rq_pool;
                rq_size = pblk_g_rq_size;
                break;
        default:
                pool = pblk->e_rq_pool;
                rq_size = pblk_g_rq_size;
        }

        rqd = mempool_alloc(pool, GFP_KERNEL);
        memset(rqd, 0, rq_size);

        return rqd;
}

/* Typically used on completion path. Cannot guarantee request consistency */
void pblk_free_rqd(struct pblk *pblk, struct nvm_rq *rqd, int type)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        mempool_t *pool;

        switch (type) {
        case PBLK_WRITE:
                kfree(((struct pblk_c_ctx *)nvm_rq_to_pdu(rqd))->lun_bitmap);
        case PBLK_WRITE_INT:
                pool = pblk->w_rq_pool;
                break;
        case PBLK_READ:
                pool = pblk->r_rq_pool;
                break;
        case PBLK_ERASE:
                pool = pblk->e_rq_pool;
                break;
        default:
                pr_err("pblk: trying to free unknown rqd type\n");
                return;
        }

        nvm_dev_dma_free(dev->parent, rqd->meta_list, rqd->dma_meta_list);
        mempool_free(rqd, pool);
}

void pblk_bio_free_pages(struct pblk *pblk, struct bio *bio, int off,
                         int nr_pages)
{
        struct bio_vec bv;
        int i;

        WARN_ON(off + nr_pages != bio->bi_vcnt);

        for (i = off; i < nr_pages + off; i++) {
                bv = bio->bi_io_vec[i];
                mempool_free(bv.bv_page, pblk->page_bio_pool);
        }
}

int pblk_bio_add_pages(struct pblk *pblk, struct bio *bio, gfp_t flags,
                       int nr_pages)
{
        struct request_queue *q = pblk->dev->q;
        struct page *page;
        int i, ret;

        for (i = 0; i < nr_pages; i++) {
                page = mempool_alloc(pblk->page_bio_pool, flags);

                ret = bio_add_pc_page(q, bio, page, PBLK_EXPOSED_PAGE_SIZE, 0);
                if (ret != PBLK_EXPOSED_PAGE_SIZE) {
                        pr_err("pblk: could not add page to bio\n");
                        mempool_free(page, pblk->page_bio_pool);
                        goto err;
                }
        }

        return 0;
err:
        pblk_bio_free_pages(pblk, bio, 0, i - 1);
        return -1;
}

static void pblk_write_kick(struct pblk *pblk)
{
        wake_up_process(pblk->writer_ts);
        mod_timer(&pblk->wtimer, jiffies + msecs_to_jiffies(1000));
}

void pblk_write_timer_fn(struct timer_list *t)
{
        struct pblk *pblk = from_timer(pblk, t, wtimer);

        /* kick the write thread every tick to flush outstanding data */
        pblk_write_kick(pblk);
}

void pblk_write_should_kick(struct pblk *pblk)
{
        unsigned int secs_avail = pblk_rb_read_count(&pblk->rwb);

        if (secs_avail >= pblk->min_write_pgs)
                pblk_write_kick(pblk);
}

void pblk_end_io_sync(struct nvm_rq *rqd)
{
        struct completion *waiting = rqd->private;

        complete(waiting);
}

static void pblk_wait_for_meta(struct pblk *pblk)
{
        do {
                if (!atomic_read(&pblk->inflight_io))
                        break;

                schedule();
        } while (1);
}

static void pblk_flush_writer(struct pblk *pblk)
{
        pblk_rb_flush(&pblk->rwb);
        do {
                if (!pblk_rb_sync_count(&pblk->rwb))
                        break;

                pblk_write_kick(pblk);
                schedule();
        } while (1);
}

struct list_head *pblk_line_gc_list(struct pblk *pblk, struct pblk_line *line)
{
        struct pblk_line_meta *lm = &pblk->lm;
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct list_head *move_list = NULL;
        int vsc = le32_to_cpu(*line->vsc);

        lockdep_assert_held(&line->lock);

        if (!vsc) {
                if (line->gc_group != PBLK_LINEGC_FULL) {
                        line->gc_group = PBLK_LINEGC_FULL;
                        move_list = &l_mg->gc_full_list;
                }
        } else if (vsc < lm->high_thrs) {
                if (line->gc_group != PBLK_LINEGC_HIGH) {
                        line->gc_group = PBLK_LINEGC_HIGH;
                        move_list = &l_mg->gc_high_list;
                }
        } else if (vsc < lm->mid_thrs) {
                if (line->gc_group != PBLK_LINEGC_MID) {
                        line->gc_group = PBLK_LINEGC_MID;
                        move_list = &l_mg->gc_mid_list;
                }
        } else if (vsc < line->sec_in_line) {
                if (line->gc_group != PBLK_LINEGC_LOW) {
                        line->gc_group = PBLK_LINEGC_LOW;
                        move_list = &l_mg->gc_low_list;
                }
        } else if (vsc == line->sec_in_line) {
                if (line->gc_group != PBLK_LINEGC_EMPTY) {
                        line->gc_group = PBLK_LINEGC_EMPTY;
                        move_list = &l_mg->gc_empty_list;
                }
        } else {
                line->state = PBLK_LINESTATE_CORRUPT;
                line->gc_group = PBLK_LINEGC_NONE;
                move_list =  &l_mg->corrupt_list;
                pr_err("pblk: corrupted vsc for line %d, vsc:%d (%d/%d/%d)\n",
                                                line->id, vsc,
                                                line->sec_in_line,
                                                lm->high_thrs, lm->mid_thrs);
        }

        return move_list;
}

void pblk_discard(struct pblk *pblk, struct bio *bio)
{
        sector_t slba = pblk_get_lba(bio);
        sector_t nr_secs = pblk_get_secs(bio);

        pblk_invalidate_range(pblk, slba, nr_secs);
}

void pblk_log_write_err(struct pblk *pblk, struct nvm_rq *rqd)
{
        atomic_long_inc(&pblk->write_failed);
#ifdef CONFIG_NVM_DEBUG
        pblk_print_failed_rqd(pblk, rqd, rqd->error);
#endif
}

void pblk_log_read_err(struct pblk *pblk, struct nvm_rq *rqd)
{
        /* Empty page read is not necessarily an error (e.g., L2P recovery) */
        if (rqd->error == NVM_RSP_ERR_EMPTYPAGE) {
                atomic_long_inc(&pblk->read_empty);
                return;
        }

        switch (rqd->error) {
        case NVM_RSP_WARN_HIGHECC:
                atomic_long_inc(&pblk->read_high_ecc);
                break;
        case NVM_RSP_ERR_FAILECC:
        case NVM_RSP_ERR_FAILCRC:
                atomic_long_inc(&pblk->read_failed);
                break;
        default:
                pr_err("pblk: unknown read error:%d\n", rqd->error);
        }
#ifdef CONFIG_NVM_DEBUG
        pblk_print_failed_rqd(pblk, rqd, rqd->error);
#endif
}

void pblk_set_sec_per_write(struct pblk *pblk, int sec_per_write)
{
        pblk->sec_per_write = sec_per_write;
}

int pblk_submit_io(struct pblk *pblk, struct nvm_rq *rqd)
{
        struct nvm_tgt_dev *dev = pblk->dev;

#ifdef CONFIG_NVM_DEBUG
        int ret;

        ret = pblk_check_io(pblk, rqd);
        if (ret)
                return ret;
#endif

        atomic_inc(&pblk->inflight_io);

        return nvm_submit_io(dev, rqd);
}

int pblk_submit_io_sync(struct pblk *pblk, struct nvm_rq *rqd)
{
        struct nvm_tgt_dev *dev = pblk->dev;

#ifdef CONFIG_NVM_DEBUG
        int ret;

        ret = pblk_check_io(pblk, rqd);
        if (ret)
                return ret;
#endif

        atomic_inc(&pblk->inflight_io);

        return nvm_submit_io_sync(dev, rqd);
}

static void pblk_bio_map_addr_endio(struct bio *bio)
{
        bio_put(bio);
}

struct bio *pblk_bio_map_addr(struct pblk *pblk, void *data,
                              unsigned int nr_secs, unsigned int len,
                              int alloc_type, gfp_t gfp_mask)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        void *kaddr = data;
        struct page *page;
        struct bio *bio;
        int i, ret;

        if (alloc_type == PBLK_KMALLOC_META)
                return bio_map_kern(dev->q, kaddr, len, gfp_mask);

        bio = bio_kmalloc(gfp_mask, nr_secs);
        if (!bio)
                return ERR_PTR(-ENOMEM);

        for (i = 0; i < nr_secs; i++) {
                page = vmalloc_to_page(kaddr);
                if (!page) {
                        pr_err("pblk: could not map vmalloc bio\n");
                        bio_put(bio);
                        bio = ERR_PTR(-ENOMEM);
                        goto out;
                }

                ret = bio_add_pc_page(dev->q, bio, page, PAGE_SIZE, 0);
                if (ret != PAGE_SIZE) {
                        pr_err("pblk: could not add page to bio\n");
                        bio_put(bio);
                        bio = ERR_PTR(-ENOMEM);
                        goto out;
                }

                kaddr += PAGE_SIZE;
        }

        bio->bi_end_io = pblk_bio_map_addr_endio;
out:
        return bio;
}

int pblk_calc_secs(struct pblk *pblk, unsigned long secs_avail,
                   unsigned long secs_to_flush)
{
        int max = pblk->sec_per_write;
        int min = pblk->min_write_pgs;
        int secs_to_sync = 0;

        if (secs_avail >= max)
                secs_to_sync = max;
        else if (secs_avail >= min)
                secs_to_sync = min * (secs_avail / min);
        else if (secs_to_flush)
                secs_to_sync = min;

        return secs_to_sync;
}

void pblk_dealloc_page(struct pblk *pblk, struct pblk_line *line, int nr_secs)
{
        u64 addr;
        int i;

        spin_lock(&line->lock);
        addr = find_next_zero_bit(line->map_bitmap,
                                        pblk->lm.sec_per_line, line->cur_sec);
        line->cur_sec = addr - nr_secs;

        for (i = 0; i < nr_secs; i++, line->cur_sec--)
                WARN_ON(!test_and_clear_bit(line->cur_sec, line->map_bitmap));
        spin_unlock(&line->lock);
}

u64 __pblk_alloc_page(struct pblk *pblk, struct pblk_line *line, int nr_secs)
{
        u64 addr;
        int i;

        lockdep_assert_held(&line->lock);

        /* logic error: ppa out-of-bounds. Prevent generating bad address */
        if (line->cur_sec + nr_secs > pblk->lm.sec_per_line) {
                WARN(1, "pblk: page allocation out of bounds\n");
                nr_secs = pblk->lm.sec_per_line - line->cur_sec;
        }

        line->cur_sec = addr = find_next_zero_bit(line->map_bitmap,
                                        pblk->lm.sec_per_line, line->cur_sec);
        for (i = 0; i < nr_secs; i++, line->cur_sec++)
                WARN_ON(test_and_set_bit(line->cur_sec, line->map_bitmap));

        return addr;
}

u64 pblk_alloc_page(struct pblk *pblk, struct pblk_line *line, int nr_secs)
{
        u64 addr;

        /* Lock needed in case a write fails and a recovery needs to remap
         * failed write buffer entries
         */
        spin_lock(&line->lock);
        addr = __pblk_alloc_page(pblk, line, nr_secs);
        line->left_msecs -= nr_secs;
        WARN(line->left_msecs < 0, "pblk: page allocation out of bounds\n");
        spin_unlock(&line->lock);

        return addr;
}

u64 pblk_lookup_page(struct pblk *pblk, struct pblk_line *line)
{
        u64 paddr;

        spin_lock(&line->lock);
        paddr = find_next_zero_bit(line->map_bitmap,
                                        pblk->lm.sec_per_line, line->cur_sec);
        spin_unlock(&line->lock);

        return paddr;
}

/*
 * Submit emeta to one LUN in the raid line at the time to avoid a deadlock when
 * taking the per LUN semaphore.
 */
static int pblk_line_submit_emeta_io(struct pblk *pblk, struct pblk_line *line,
                                     void *emeta_buf, u64 paddr, int dir)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct pblk_line_meta *lm = &pblk->lm;
        void *ppa_list, *meta_list;
        struct bio *bio;
        struct nvm_rq rqd;
        dma_addr_t dma_ppa_list, dma_meta_list;
        int min = pblk->min_write_pgs;
        int left_ppas = lm->emeta_sec[0];
        int id = line->id;
        int rq_ppas, rq_len;
        int cmd_op, bio_op;
        int i, j;
        int ret;

        if (dir == PBLK_WRITE) {
                bio_op = REQ_OP_WRITE;
                cmd_op = NVM_OP_PWRITE;
        } else if (dir == PBLK_READ) {
                bio_op = REQ_OP_READ;
                cmd_op = NVM_OP_PREAD;
        } else
                return -EINVAL;

        meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
                                                        &dma_meta_list);
        if (!meta_list)
                return -ENOMEM;

        ppa_list = meta_list + pblk_dma_meta_size;
        dma_ppa_list = dma_meta_list + pblk_dma_meta_size;

next_rq:
        memset(&rqd, 0, sizeof(struct nvm_rq));

        rq_ppas = pblk_calc_secs(pblk, left_ppas, 0);
        rq_len = rq_ppas * geo->csecs;

        bio = pblk_bio_map_addr(pblk, emeta_buf, rq_ppas, rq_len,
                                        l_mg->emeta_alloc_type, GFP_KERNEL);
        if (IS_ERR(bio)) {
                ret = PTR_ERR(bio);
                goto free_rqd_dma;
        }

        bio->bi_iter.bi_sector = 0; /* internal bio */
        bio_set_op_attrs(bio, bio_op, 0);

        rqd.bio = bio;
        rqd.meta_list = meta_list;
        rqd.ppa_list = ppa_list;
        rqd.dma_meta_list = dma_meta_list;
        rqd.dma_ppa_list = dma_ppa_list;
        rqd.opcode = cmd_op;
        rqd.nr_ppas = rq_ppas;

        if (dir == PBLK_WRITE) {
                struct pblk_sec_meta *meta_list = rqd.meta_list;

                rqd.flags = pblk_set_progr_mode(pblk, PBLK_WRITE);
                for (i = 0; i < rqd.nr_ppas; ) {
                        spin_lock(&line->lock);
                        paddr = __pblk_alloc_page(pblk, line, min);
                        spin_unlock(&line->lock);
                        for (j = 0; j < min; j++, i++, paddr++) {
                                meta_list[i].lba = cpu_to_le64(ADDR_EMPTY);
                                rqd.ppa_list[i] =
                                        addr_to_gen_ppa(pblk, paddr, id);
                        }
                }
        } else {
                for (i = 0; i < rqd.nr_ppas; ) {
                        struct ppa_addr ppa = addr_to_gen_ppa(pblk, paddr, id);
                        int pos = pblk_ppa_to_pos(geo, ppa);
                        int read_type = PBLK_READ_RANDOM;

                        if (pblk_io_aligned(pblk, rq_ppas))
                                read_type = PBLK_READ_SEQUENTIAL;
                        rqd.flags = pblk_set_read_mode(pblk, read_type);

                        while (test_bit(pos, line->blk_bitmap)) {
                                paddr += min;
                                if (pblk_boundary_paddr_checks(pblk, paddr)) {
                                        pr_err("pblk: corrupt emeta line:%d\n",
                                                                line->id);
                                        bio_put(bio);
                                        ret = -EINTR;
                                        goto free_rqd_dma;
                                }

                                ppa = addr_to_gen_ppa(pblk, paddr, id);
                                pos = pblk_ppa_to_pos(geo, ppa);
                        }

                        if (pblk_boundary_paddr_checks(pblk, paddr + min)) {
                                pr_err("pblk: corrupt emeta line:%d\n",
                                                                line->id);
                                bio_put(bio);
                                ret = -EINTR;
                                goto free_rqd_dma;
                        }

                        for (j = 0; j < min; j++, i++, paddr++)
                                rqd.ppa_list[i] =
                                        addr_to_gen_ppa(pblk, paddr, line->id);
                }
        }

        ret = pblk_submit_io_sync(pblk, &rqd);
        if (ret) {
                pr_err("pblk: emeta I/O submission failed: %d\n", ret);
                bio_put(bio);
                goto free_rqd_dma;
        }

        atomic_dec(&pblk->inflight_io);

        if (rqd.error) {
                if (dir == PBLK_WRITE)
                        pblk_log_write_err(pblk, &rqd);
                else
                        pblk_log_read_err(pblk, &rqd);
        }

        emeta_buf += rq_len;
        left_ppas -= rq_ppas;
        if (left_ppas)
                goto next_rq;
free_rqd_dma:
        nvm_dev_dma_free(dev->parent, rqd.meta_list, rqd.dma_meta_list);
        return ret;
}

u64 pblk_line_smeta_start(struct pblk *pblk, struct pblk_line *line)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct pblk_line_meta *lm = &pblk->lm;
        int bit;

        /* This usually only happens on bad lines */
        bit = find_first_zero_bit(line->blk_bitmap, lm->blk_per_line);
        if (bit >= lm->blk_per_line)
                return -1;

        return bit * geo->ws_opt;
}

static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line,
                                     u64 paddr, int dir)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct pblk_line_meta *lm = &pblk->lm;
        struct bio *bio;
        struct nvm_rq rqd;
        __le64 *lba_list = NULL;
        int i, ret;
        int cmd_op, bio_op;
        int flags;

        if (dir == PBLK_WRITE) {
                bio_op = REQ_OP_WRITE;
                cmd_op = NVM_OP_PWRITE;
                flags = pblk_set_progr_mode(pblk, PBLK_WRITE);
                lba_list = emeta_to_lbas(pblk, line->emeta->buf);
        } else if (dir == PBLK_READ_RECOV || dir == PBLK_READ) {
                bio_op = REQ_OP_READ;
                cmd_op = NVM_OP_PREAD;
                flags = pblk_set_read_mode(pblk, PBLK_READ_SEQUENTIAL);
        } else
                return -EINVAL;

        memset(&rqd, 0, sizeof(struct nvm_rq));

        rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
                                                        &rqd.dma_meta_list);
        if (!rqd.meta_list)
                return -ENOMEM;

        rqd.ppa_list = rqd.meta_list + pblk_dma_meta_size;
        rqd.dma_ppa_list = rqd.dma_meta_list + pblk_dma_meta_size;

        bio = bio_map_kern(dev->q, line->smeta, lm->smeta_len, GFP_KERNEL);
        if (IS_ERR(bio)) {
                ret = PTR_ERR(bio);
                goto free_ppa_list;
        }

        bio->bi_iter.bi_sector = 0; /* internal bio */
        bio_set_op_attrs(bio, bio_op, 0);

        rqd.bio = bio;
        rqd.opcode = cmd_op;
        rqd.flags = flags;
        rqd.nr_ppas = lm->smeta_sec;

        for (i = 0; i < lm->smeta_sec; i++, paddr++) {
                struct pblk_sec_meta *meta_list = rqd.meta_list;

                rqd.ppa_list[i] = addr_to_gen_ppa(pblk, paddr, line->id);

                if (dir == PBLK_WRITE) {
                        __le64 addr_empty = cpu_to_le64(ADDR_EMPTY);

                        meta_list[i].lba = lba_list[paddr] = addr_empty;
                }
        }

        /*
         * This I/O is sent by the write thread when a line is replace. Since
         * the write thread is the only one sending write and erase commands,
         * there is no need to take the LUN semaphore.
         */
        ret = pblk_submit_io_sync(pblk, &rqd);
        if (ret) {
                pr_err("pblk: smeta I/O submission failed: %d\n", ret);
                bio_put(bio);
                goto free_ppa_list;
        }

        atomic_dec(&pblk->inflight_io);

        if (rqd.error) {
                if (dir == PBLK_WRITE)
                        pblk_log_write_err(pblk, &rqd);
                else if (dir == PBLK_READ)
                        pblk_log_read_err(pblk, &rqd);
        }

free_ppa_list:
        nvm_dev_dma_free(dev->parent, rqd.meta_list, rqd.dma_meta_list);

        return ret;
}

int pblk_line_read_smeta(struct pblk *pblk, struct pblk_line *line)
{
        u64 bpaddr = pblk_line_smeta_start(pblk, line);

        return pblk_line_submit_smeta_io(pblk, line, bpaddr, PBLK_READ_RECOV);
}

int pblk_line_read_emeta(struct pblk *pblk, struct pblk_line *line,
                         void *emeta_buf)
{
        return pblk_line_submit_emeta_io(pblk, line, emeta_buf,
                                                line->emeta_ssec, PBLK_READ);
}

static void pblk_setup_e_rq(struct pblk *pblk, struct nvm_rq *rqd,
                            struct ppa_addr ppa)
{
        rqd->opcode = NVM_OP_ERASE;
        rqd->ppa_addr = ppa;
        rqd->nr_ppas = 1;
        rqd->flags = pblk_set_progr_mode(pblk, PBLK_ERASE);
        rqd->bio = NULL;
}

static int pblk_blk_erase_sync(struct pblk *pblk, struct ppa_addr ppa)
{
        struct nvm_rq rqd;
        int ret = 0;

        memset(&rqd, 0, sizeof(struct nvm_rq));

        pblk_setup_e_rq(pblk, &rqd, ppa);

        /* The write thread schedules erases so that it minimizes disturbances
         * with writes. Thus, there is no need to take the LUN semaphore.
         */
        ret = pblk_submit_io_sync(pblk, &rqd);
        if (ret) {
                struct nvm_tgt_dev *dev = pblk->dev;
                struct nvm_geo *geo = &dev->geo;

                pr_err("pblk: could not sync erase line:%d,blk:%d\n",
                                        pblk_ppa_to_line(ppa),
                                        pblk_ppa_to_pos(geo, ppa));

                rqd.error = ret;
                goto out;
        }

out:
        rqd.private = pblk;
        __pblk_end_io_erase(pblk, &rqd);

        return ret;
}

int pblk_line_erase(struct pblk *pblk, struct pblk_line *line)
{
        struct pblk_line_meta *lm = &pblk->lm;
        struct ppa_addr ppa;
        int ret, bit = -1;

        /* Erase only good blocks, one at a time */
        do {
                spin_lock(&line->lock);
                bit = find_next_zero_bit(line->erase_bitmap, lm->blk_per_line,
                                                                bit + 1);
                if (bit >= lm->blk_per_line) {
                        spin_unlock(&line->lock);
                        break;
                }

                ppa = pblk->luns[bit].bppa; /* set ch and lun */
                ppa.a.blk = line->id;

                atomic_dec(&line->left_eblks);
                WARN_ON(test_and_set_bit(bit, line->erase_bitmap));
                spin_unlock(&line->lock);

                ret = pblk_blk_erase_sync(pblk, ppa);
                if (ret) {
                        pr_err("pblk: failed to erase line %d\n", line->id);
                        return ret;
                }
        } while (1);

        return 0;
}

static void pblk_line_setup_metadata(struct pblk_line *line,
                                     struct pblk_line_mgmt *l_mg,
                                     struct pblk_line_meta *lm)
{
        int meta_line;

        lockdep_assert_held(&l_mg->free_lock);

retry_meta:
        meta_line = find_first_zero_bit(&l_mg->meta_bitmap, PBLK_DATA_LINES);
        if (meta_line == PBLK_DATA_LINES) {
                spin_unlock(&l_mg->free_lock);
                io_schedule();
                spin_lock(&l_mg->free_lock);
                goto retry_meta;
        }

        set_bit(meta_line, &l_mg->meta_bitmap);
        line->meta_line = meta_line;

        line->smeta = l_mg->sline_meta[meta_line];
        line->emeta = l_mg->eline_meta[meta_line];

        memset(line->smeta, 0, lm->smeta_len);
        memset(line->emeta->buf, 0, lm->emeta_len[0]);

        line->emeta->mem = 0;
        atomic_set(&line->emeta->sync, 0);
}

/* For now lines are always assumed full lines. Thus, smeta former and current
 * lun bitmaps are omitted.
 */
static int pblk_line_init_metadata(struct pblk *pblk, struct pblk_line *line,
                                  struct pblk_line *cur)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct pblk_line_meta *lm = &pblk->lm;
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct pblk_emeta *emeta = line->emeta;

        struct line_emeta *emeta_buf = emeta->buf;
        struct line_smeta *smeta_buf = (struct line_smeta *)line->smeta;
        int nr_blk_line;

        /* After erasing the line, new bad blocks might appear and we risk
         * having an invalid line
         */
        nr_blk_line = lm->blk_per_line -
                        bitmap_weight(line->blk_bitmap, lm->blk_per_line);
        if (nr_blk_line < lm->min_blk_line) {
                spin_lock(&l_mg->free_lock);
                spin_lock(&line->lock);
                line->state = PBLK_LINESTATE_BAD;
                spin_unlock(&line->lock);

                list_add_tail(&line->list, &l_mg->bad_list);
                spin_unlock(&l_mg->free_lock);

                pr_debug("pblk: line %d is bad\n", line->id);

                return 0;
        }

        /* Run-time metadata */
        line->lun_bitmap = ((void *)(smeta_buf)) + sizeof(struct line_smeta);

        /* Mark LUNs allocated in this line (all for now) */
        bitmap_set(line->lun_bitmap, 0, lm->lun_bitmap_len);

        smeta_buf->header.identifier = cpu_to_le32(PBLK_MAGIC);
        memcpy(smeta_buf->header.uuid, pblk->instance_uuid, 16);
        smeta_buf->header.id = cpu_to_le32(line->id);
        smeta_buf->header.type = cpu_to_le16(line->type);
        smeta_buf->header.version_major = SMETA_VERSION_MAJOR;
        smeta_buf->header.version_minor = SMETA_VERSION_MINOR;

        /* Start metadata */
        smeta_buf->seq_nr = cpu_to_le64(line->seq_nr);
        smeta_buf->window_wr_lun = cpu_to_le32(geo->all_luns);

        /* Fill metadata among lines */
        if (cur) {
                memcpy(line->lun_bitmap, cur->lun_bitmap, lm->lun_bitmap_len);
                smeta_buf->prev_id = cpu_to_le32(cur->id);
                cur->emeta->buf->next_id = cpu_to_le32(line->id);
        } else {
                smeta_buf->prev_id = cpu_to_le32(PBLK_LINE_EMPTY);
        }

        /* All smeta must be set at this point */
        smeta_buf->header.crc = cpu_to_le32(
                        pblk_calc_meta_header_crc(pblk, &smeta_buf->header));
        smeta_buf->crc = cpu_to_le32(pblk_calc_smeta_crc(pblk, smeta_buf));

        /* End metadata */
        memcpy(&emeta_buf->header, &smeta_buf->header,
                                                sizeof(struct line_header));

        emeta_buf->header.version_major = EMETA_VERSION_MAJOR;
        emeta_buf->header.version_minor = EMETA_VERSION_MINOR;
        emeta_buf->header.crc = cpu_to_le32(
                        pblk_calc_meta_header_crc(pblk, &emeta_buf->header));

        emeta_buf->seq_nr = cpu_to_le64(line->seq_nr);
        emeta_buf->nr_lbas = cpu_to_le64(line->sec_in_line);
        emeta_buf->nr_valid_lbas = cpu_to_le64(0);
        emeta_buf->next_id = cpu_to_le32(PBLK_LINE_EMPTY);
        emeta_buf->crc = cpu_to_le32(0);
        emeta_buf->prev_id = smeta_buf->prev_id;

        return 1;
}

/* For now lines are always assumed full lines. Thus, smeta former and current
 * lun bitmaps are omitted.
 */
static int pblk_line_init_bb(struct pblk *pblk, struct pblk_line *line,
                             int init)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct pblk_line_meta *lm = &pblk->lm;
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        u64 off;
        int bit = -1;
        int emeta_secs;

        line->sec_in_line = lm->sec_per_line;

        /* Capture bad block information on line mapping bitmaps */
        while ((bit = find_next_bit(line->blk_bitmap, lm->blk_per_line,
                                        bit + 1)) < lm->blk_per_line) {
                off = bit * geo->ws_opt;
                bitmap_shift_left(l_mg->bb_aux, l_mg->bb_template, off,
                                                        lm->sec_per_line);
                bitmap_or(line->map_bitmap, line->map_bitmap, l_mg->bb_aux,
                                                        lm->sec_per_line);
                line->sec_in_line -= geo->clba;
        }

        /* Mark smeta metadata sectors as bad sectors */
        bit = find_first_zero_bit(line->blk_bitmap, lm->blk_per_line);
        off = bit * geo->ws_opt;
        bitmap_set(line->map_bitmap, off, lm->smeta_sec);
        line->sec_in_line -= lm->smeta_sec;
        line->smeta_ssec = off;
        line->cur_sec = off + lm->smeta_sec;

        if (init && pblk_line_submit_smeta_io(pblk, line, off, PBLK_WRITE)) {
                pr_debug("pblk: line smeta I/O failed. Retry\n");
                return 1;
        }

        bitmap_copy(line->invalid_bitmap, line->map_bitmap, lm->sec_per_line);

        /* Mark emeta metadata sectors as bad sectors. We need to consider bad
         * blocks to make sure that there are enough sectors to store emeta
         */
        emeta_secs = lm->emeta_sec[0];
        off = lm->sec_per_line;
        while (emeta_secs) {
                off -= geo->ws_opt;
                if (!test_bit(off, line->invalid_bitmap)) {
                        bitmap_set(line->invalid_bitmap, off, geo->ws_opt);
                        emeta_secs -= geo->ws_opt;
                }
        }

        line->emeta_ssec = off;
        line->sec_in_line -= lm->emeta_sec[0];
        line->nr_valid_lbas = 0;
        line->left_msecs = line->sec_in_line;
        *line->vsc = cpu_to_le32(line->sec_in_line);

        if (lm->sec_per_line - line->sec_in_line !=
                bitmap_weight(line->invalid_bitmap, lm->sec_per_line)) {
                spin_lock(&line->lock);
                line->state = PBLK_LINESTATE_BAD;
                spin_unlock(&line->lock);

                list_add_tail(&line->list, &l_mg->bad_list);
                pr_err("pblk: unexpected line %d is bad\n", line->id);

                return 0;
        }

        return 1;
}

static int pblk_prepare_new_line(struct pblk *pblk, struct pblk_line *line)
{
        struct pblk_line_meta *lm = &pblk->lm;
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        int blk_to_erase = atomic_read(&line->blk_in_line);
        int i;

        for (i = 0; i < lm->blk_per_line; i++) {
                struct pblk_lun *rlun = &pblk->luns[i];
                int pos = pblk_ppa_to_pos(geo, rlun->bppa);
                int state = line->chks[pos].state;

                /* Free chunks should not be erased */
                if (state & NVM_CHK_ST_FREE) {
                        set_bit(pblk_ppa_to_pos(geo, rlun->bppa),
                                                        line->erase_bitmap);
                        blk_to_erase--;
                }
        }

        return blk_to_erase;
}

static int pblk_line_prepare(struct pblk *pblk, struct pblk_line *line)
{
        struct pblk_line_meta *lm = &pblk->lm;
        int blk_to_erase;

        line->map_bitmap = kzalloc(lm->sec_bitmap_len, GFP_ATOMIC);
        if (!line->map_bitmap)
                return -ENOMEM;

        /* will be initialized using bb info from map_bitmap */
        line->invalid_bitmap = kmalloc(lm->sec_bitmap_len, GFP_ATOMIC);
        if (!line->invalid_bitmap) {
                kfree(line->map_bitmap);
                return -ENOMEM;
        }

        /* Bad blocks do not need to be erased */
        bitmap_copy(line->erase_bitmap, line->blk_bitmap, lm->blk_per_line);

        spin_lock(&line->lock);

        /* If we have not written to this line, we need to mark up free chunks
         * as already erased
         */
        if (line->state == PBLK_LINESTATE_NEW) {
                blk_to_erase = pblk_prepare_new_line(pblk, line);
                line->state = PBLK_LINESTATE_FREE;
        } else {
                blk_to_erase = atomic_read(&line->blk_in_line);
        }

        if (line->state != PBLK_LINESTATE_FREE) {
                kfree(line->map_bitmap);
                kfree(line->invalid_bitmap);
                spin_unlock(&line->lock);
                WARN(1, "pblk: corrupted line %d, state %d\n",
                                                        line->id, line->state);
                return -EAGAIN;
        }

        line->state = PBLK_LINESTATE_OPEN;

        atomic_set(&line->left_eblks, blk_to_erase);
        atomic_set(&line->left_seblks, blk_to_erase);

        line->meta_distance = lm->meta_distance;
        spin_unlock(&line->lock);

        kref_init(&line->ref);

        return 0;
}

int pblk_line_recov_alloc(struct pblk *pblk, struct pblk_line *line)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        int ret;

        spin_lock(&l_mg->free_lock);
        l_mg->data_line = line;
        list_del(&line->list);

        ret = pblk_line_prepare(pblk, line);
        if (ret) {
                list_add(&line->list, &l_mg->free_list);
                spin_unlock(&l_mg->free_lock);
                return ret;
        }
        spin_unlock(&l_mg->free_lock);

        pblk_rl_free_lines_dec(&pblk->rl, line, true);

        if (!pblk_line_init_bb(pblk, line, 0)) {
                list_add(&line->list, &l_mg->free_list);
                return -EINTR;
        }

        return 0;
}

void pblk_line_recov_close(struct pblk *pblk, struct pblk_line *line)
{
        kfree(line->map_bitmap);
        line->map_bitmap = NULL;
        line->smeta = NULL;
        line->emeta = NULL;
}

struct pblk_line *pblk_line_get(struct pblk *pblk)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct pblk_line_meta *lm = &pblk->lm;
        struct pblk_line *line;
        int ret, bit;

        lockdep_assert_held(&l_mg->free_lock);

retry:
        if (list_empty(&l_mg->free_list)) {
                pr_err("pblk: no free lines\n");
                return NULL;
        }

        line = list_first_entry(&l_mg->free_list, struct pblk_line, list);
        list_del(&line->list);
        l_mg->nr_free_lines--;

        bit = find_first_zero_bit(line->blk_bitmap, lm->blk_per_line);
        if (unlikely(bit >= lm->blk_per_line)) {
                spin_lock(&line->lock);
                line->state = PBLK_LINESTATE_BAD;
                spin_unlock(&line->lock);

                list_add_tail(&line->list, &l_mg->bad_list);

                pr_debug("pblk: line %d is bad\n", line->id);
                goto retry;
        }

        ret = pblk_line_prepare(pblk, line);
        if (ret) {
                if (ret == -EAGAIN) {
                        list_add(&line->list, &l_mg->corrupt_list);
                        goto retry;
                } else {
                        pr_err("pblk: failed to prepare line %d\n", line->id);
                        list_add(&line->list, &l_mg->free_list);
                        l_mg->nr_free_lines++;
                        return NULL;
                }
        }

        return line;
}

static struct pblk_line *pblk_line_retry(struct pblk *pblk,
                                         struct pblk_line *line)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct pblk_line *retry_line;

retry:
        spin_lock(&l_mg->free_lock);
        retry_line = pblk_line_get(pblk);
        if (!retry_line) {
                l_mg->data_line = NULL;
                spin_unlock(&l_mg->free_lock);
                return NULL;
        }

        retry_line->smeta = line->smeta;
        retry_line->emeta = line->emeta;
        retry_line->meta_line = line->meta_line;

        pblk_line_free(pblk, line);
        l_mg->data_line = retry_line;
        spin_unlock(&l_mg->free_lock);

        pblk_rl_free_lines_dec(&pblk->rl, line, false);

        if (pblk_line_erase(pblk, retry_line))
                goto retry;

        return retry_line;
}

static void pblk_set_space_limit(struct pblk *pblk)
{
        struct pblk_rl *rl = &pblk->rl;

        atomic_set(&rl->rb_space, 0);
}

struct pblk_line *pblk_line_get_first_data(struct pblk *pblk)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct pblk_line *line;

        spin_lock(&l_mg->free_lock);
        line = pblk_line_get(pblk);
        if (!line) {
                spin_unlock(&l_mg->free_lock);
                return NULL;
        }

        line->seq_nr = l_mg->d_seq_nr++;
        line->type = PBLK_LINETYPE_DATA;
        l_mg->data_line = line;

        pblk_line_setup_metadata(line, l_mg, &pblk->lm);

        /* Allocate next line for preparation */
        l_mg->data_next = pblk_line_get(pblk);
        if (!l_mg->data_next) {
                /* If we cannot get a new line, we need to stop the pipeline.
                 * Only allow as many writes in as we can store safely and then
                 * fail gracefully
                 */
                pblk_set_space_limit(pblk);

                l_mg->data_next = NULL;
        } else {
                l_mg->data_next->seq_nr = l_mg->d_seq_nr++;
                l_mg->data_next->type = PBLK_LINETYPE_DATA;
        }
        spin_unlock(&l_mg->free_lock);

        if (pblk_line_erase(pblk, line)) {
                line = pblk_line_retry(pblk, line);
                if (!line)
                        return NULL;
        }

retry_setup:
        if (!pblk_line_init_metadata(pblk, line, NULL)) {
                line = pblk_line_retry(pblk, line);
                if (!line)
                        return NULL;

                goto retry_setup;
        }

        if (!pblk_line_init_bb(pblk, line, 1)) {
                line = pblk_line_retry(pblk, line);
                if (!line)
                        return NULL;

                goto retry_setup;
        }

        pblk_rl_free_lines_dec(&pblk->rl, line, true);

        return line;
}

static void pblk_stop_writes(struct pblk *pblk, struct pblk_line *line)
{
        lockdep_assert_held(&pblk->l_mg.free_lock);

        pblk_set_space_limit(pblk);
        pblk->state = PBLK_STATE_STOPPING;
}

static void pblk_line_close_meta_sync(struct pblk *pblk)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct pblk_line_meta *lm = &pblk->lm;
        struct pblk_line *line, *tline;
        LIST_HEAD(list);

        spin_lock(&l_mg->close_lock);
        if (list_empty(&l_mg->emeta_list)) {
                spin_unlock(&l_mg->close_lock);
                return;
        }

        list_cut_position(&list, &l_mg->emeta_list, l_mg->emeta_list.prev);
        spin_unlock(&l_mg->close_lock);

        list_for_each_entry_safe(line, tline, &list, list) {
                struct pblk_emeta *emeta = line->emeta;

                while (emeta->mem < lm->emeta_len[0]) {
                        int ret;

                        ret = pblk_submit_meta_io(pblk, line);
                        if (ret) {
                                pr_err("pblk: sync meta line %d failed (%d)\n",
                                                        line->id, ret);
                                return;
                        }
                }
        }

        pblk_wait_for_meta(pblk);
        flush_workqueue(pblk->close_wq);
}

void pblk_pipeline_stop(struct pblk *pblk)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        int ret;

        spin_lock(&l_mg->free_lock);
        if (pblk->state == PBLK_STATE_RECOVERING ||
                                        pblk->state == PBLK_STATE_STOPPED) {
                spin_unlock(&l_mg->free_lock);
                return;
        }
        pblk->state = PBLK_STATE_RECOVERING;
        spin_unlock(&l_mg->free_lock);

        pblk_flush_writer(pblk);
        pblk_wait_for_meta(pblk);

        ret = pblk_recov_pad(pblk);
        if (ret) {
                pr_err("pblk: could not close data on teardown(%d)\n", ret);
                return;
        }

        flush_workqueue(pblk->bb_wq);
        pblk_line_close_meta_sync(pblk);

        spin_lock(&l_mg->free_lock);
        pblk->state = PBLK_STATE_STOPPED;
        l_mg->data_line = NULL;
        l_mg->data_next = NULL;
        spin_unlock(&l_mg->free_lock);
}

struct pblk_line *pblk_line_replace_data(struct pblk *pblk)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct pblk_line *cur, *new = NULL;
        unsigned int left_seblks;

        cur = l_mg->data_line;
        new = l_mg->data_next;
        if (!new)
                goto out;
        l_mg->data_line = new;

        spin_lock(&l_mg->free_lock);
        pblk_line_setup_metadata(new, l_mg, &pblk->lm);
        spin_unlock(&l_mg->free_lock);

retry_erase:
        left_seblks = atomic_read(&new->left_seblks);
        if (left_seblks) {
                /* If line is not fully erased, erase it */
                if (atomic_read(&new->left_eblks)) {
                        if (pblk_line_erase(pblk, new))
                                goto out;
                } else {
                        io_schedule();
                }
                goto retry_erase;
        }

retry_setup:
        if (!pblk_line_init_metadata(pblk, new, cur)) {
                new = pblk_line_retry(pblk, new);
                if (!new)
                        goto out;

                goto retry_setup;
        }

        if (!pblk_line_init_bb(pblk, new, 1)) {
                new = pblk_line_retry(pblk, new);
                if (!new)
                        goto out;

                goto retry_setup;
        }

        pblk_rl_free_lines_dec(&pblk->rl, new, true);

        /* Allocate next line for preparation */
        spin_lock(&l_mg->free_lock);
        l_mg->data_next = pblk_line_get(pblk);
        if (!l_mg->data_next) {
                /* If we cannot get a new line, we need to stop the pipeline.
                 * Only allow as many writes in as we can store safely and then
                 * fail gracefully
                 */
                pblk_stop_writes(pblk, new);
                l_mg->data_next = NULL;
        } else {
                l_mg->data_next->seq_nr = l_mg->d_seq_nr++;
                l_mg->data_next->type = PBLK_LINETYPE_DATA;
        }
        spin_unlock(&l_mg->free_lock);

out:
        return new;
}

void pblk_line_free(struct pblk *pblk, struct pblk_line *line)
{
        kfree(line->map_bitmap);
        kfree(line->invalid_bitmap);

        *line->vsc = cpu_to_le32(EMPTY_ENTRY);

        line->map_bitmap = NULL;
        line->invalid_bitmap = NULL;
        line->smeta = NULL;
        line->emeta = NULL;
}

static void __pblk_line_put(struct pblk *pblk, struct pblk_line *line)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct pblk_gc *gc = &pblk->gc;

        spin_lock(&line->lock);
        WARN_ON(line->state != PBLK_LINESTATE_GC);
        line->state = PBLK_LINESTATE_FREE;
        line->gc_group = PBLK_LINEGC_NONE;
        pblk_line_free(pblk, line);
        spin_unlock(&line->lock);

        atomic_dec(&gc->pipeline_gc);

        spin_lock(&l_mg->free_lock);
        list_add_tail(&line->list, &l_mg->free_list);
        l_mg->nr_free_lines++;
        spin_unlock(&l_mg->free_lock);

        pblk_rl_free_lines_inc(&pblk->rl, line);
}

static void pblk_line_put_ws(struct work_struct *work)
{
        struct pblk_line_ws *line_put_ws = container_of(work,
                                                struct pblk_line_ws, ws);
        struct pblk *pblk = line_put_ws->pblk;
        struct pblk_line *line = line_put_ws->line;

        __pblk_line_put(pblk, line);
        mempool_free(line_put_ws, pblk->gen_ws_pool);
}

void pblk_line_put(struct kref *ref)
{
        struct pblk_line *line = container_of(ref, struct pblk_line, ref);
        struct pblk *pblk = line->pblk;

        __pblk_line_put(pblk, line);
}

void pblk_line_put_wq(struct kref *ref)
{
        struct pblk_line *line = container_of(ref, struct pblk_line, ref);
        struct pblk *pblk = line->pblk;
        struct pblk_line_ws *line_put_ws;

        line_put_ws = mempool_alloc(pblk->gen_ws_pool, GFP_ATOMIC);
        if (!line_put_ws)
                return;

        line_put_ws->pblk = pblk;
        line_put_ws->line = line;
        line_put_ws->priv = NULL;

        INIT_WORK(&line_put_ws->ws, pblk_line_put_ws);
        queue_work(pblk->r_end_wq, &line_put_ws->ws);
}

int pblk_blk_erase_async(struct pblk *pblk, struct ppa_addr ppa)
{
        struct nvm_rq *rqd;
        int err;

        rqd = pblk_alloc_rqd(pblk, PBLK_ERASE);

        pblk_setup_e_rq(pblk, rqd, ppa);

        rqd->end_io = pblk_end_io_erase;
        rqd->private = pblk;

        /* The write thread schedules erases so that it minimizes disturbances
         * with writes. Thus, there is no need to take the LUN semaphore.
         */
        err = pblk_submit_io(pblk, rqd);
        if (err) {
                struct nvm_tgt_dev *dev = pblk->dev;
                struct nvm_geo *geo = &dev->geo;

                pr_err("pblk: could not async erase line:%d,blk:%d\n",
                                        pblk_ppa_to_line(ppa),
                                        pblk_ppa_to_pos(geo, ppa));
        }

        return err;
}

struct pblk_line *pblk_line_get_data(struct pblk *pblk)
{
        return pblk->l_mg.data_line;
}

/* For now, always erase next line */
struct pblk_line *pblk_line_get_erase(struct pblk *pblk)
{
        return pblk->l_mg.data_next;
}

int pblk_line_is_full(struct pblk_line *line)
{
        return (line->left_msecs == 0);
}

static void pblk_line_should_sync_meta(struct pblk *pblk)
{
        if (pblk_rl_is_limit(&pblk->rl))
                pblk_line_close_meta_sync(pblk);
}

void pblk_line_close(struct pblk *pblk, struct pblk_line *line)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct pblk_line_meta *lm = &pblk->lm;
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct list_head *move_list;
        int i;

#ifdef CONFIG_NVM_DEBUG
        WARN(!bitmap_full(line->map_bitmap, lm->sec_per_line),
                                "pblk: corrupt closed line %d\n", line->id);
#endif

        spin_lock(&l_mg->free_lock);
        WARN_ON(!test_and_clear_bit(line->meta_line, &l_mg->meta_bitmap));
        spin_unlock(&l_mg->free_lock);

        spin_lock(&l_mg->gc_lock);
        spin_lock(&line->lock);
        WARN_ON(line->state != PBLK_LINESTATE_OPEN);
        line->state = PBLK_LINESTATE_CLOSED;
        move_list = pblk_line_gc_list(pblk, line);

        list_add_tail(&line->list, move_list);

        kfree(line->map_bitmap);
        line->map_bitmap = NULL;
        line->smeta = NULL;
        line->emeta = NULL;

        for (i = 0; i < lm->blk_per_line; i++) {
                struct pblk_lun *rlun = &pblk->luns[i];
                int pos = pblk_ppa_to_pos(geo, rlun->bppa);
                int state = line->chks[pos].state;

                if (!(state & NVM_CHK_ST_OFFLINE))
                        state = NVM_CHK_ST_CLOSED;
        }

        spin_unlock(&line->lock);
        spin_unlock(&l_mg->gc_lock);
}

void pblk_line_close_meta(struct pblk *pblk, struct pblk_line *line)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct pblk_line_meta *lm = &pblk->lm;
        struct pblk_emeta *emeta = line->emeta;
        struct line_emeta *emeta_buf = emeta->buf;
        struct wa_counters *wa = emeta_to_wa(lm, emeta_buf);

        /* No need for exact vsc value; avoid a big line lock and take aprox. */
        memcpy(emeta_to_vsc(pblk, emeta_buf), l_mg->vsc_list, lm->vsc_list_len);
        memcpy(emeta_to_bb(emeta_buf), line->blk_bitmap, lm->blk_bitmap_len);

        wa->user = cpu_to_le64(atomic64_read(&pblk->user_wa));
        wa->pad = cpu_to_le64(atomic64_read(&pblk->pad_wa));
        wa->gc = cpu_to_le64(atomic64_read(&pblk->gc_wa));

        emeta_buf->nr_valid_lbas = cpu_to_le64(line->nr_valid_lbas);
        emeta_buf->crc = cpu_to_le32(pblk_calc_emeta_crc(pblk, emeta_buf));

        spin_lock(&l_mg->close_lock);
        spin_lock(&line->lock);
        list_add_tail(&line->list, &l_mg->emeta_list);
        spin_unlock(&line->lock);
        spin_unlock(&l_mg->close_lock);

        pblk_line_should_sync_meta(pblk);
}

void pblk_line_close_ws(struct work_struct *work)
{
        struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
                                                                        ws);
        struct pblk *pblk = line_ws->pblk;
        struct pblk_line *line = line_ws->line;

        pblk_line_close(pblk, line);
        mempool_free(line_ws, pblk->gen_ws_pool);
}

void pblk_gen_run_ws(struct pblk *pblk, struct pblk_line *line, void *priv,
                      void (*work)(struct work_struct *), gfp_t gfp_mask,
                      struct workqueue_struct *wq)
{
        struct pblk_line_ws *line_ws;

        line_ws = mempool_alloc(pblk->gen_ws_pool, gfp_mask);

        line_ws->pblk = pblk;
        line_ws->line = line;
        line_ws->priv = priv;

        INIT_WORK(&line_ws->ws, work);
        queue_work(wq, &line_ws->ws);
}

static void __pblk_down_page(struct pblk *pblk, struct ppa_addr *ppa_list,
                             int nr_ppas, int pos)
{
        struct pblk_lun *rlun = &pblk->luns[pos];
        int ret;

        /*
         * Only send one inflight I/O per LUN. Since we map at a page
         * granurality, all ppas in the I/O will map to the same LUN
         */
#ifdef CONFIG_NVM_DEBUG
        int i;

        for (i = 1; i < nr_ppas; i++)
                WARN_ON(ppa_list[0].a.lun != ppa_list[i].a.lun ||
                                ppa_list[0].a.ch != ppa_list[i].a.ch);
#endif

        ret = down_timeout(&rlun->wr_sem, msecs_to_jiffies(30000));
        if (ret == -ETIME || ret == -EINTR)
                pr_err("pblk: taking lun semaphore timed out: err %d\n", -ret);
}

void pblk_down_page(struct pblk *pblk, struct ppa_addr *ppa_list, int nr_ppas)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        int pos = pblk_ppa_to_pos(geo, ppa_list[0]);

        __pblk_down_page(pblk, ppa_list, nr_ppas, pos);
}

void pblk_down_rq(struct pblk *pblk, struct ppa_addr *ppa_list, int nr_ppas,
                  unsigned long *lun_bitmap)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        int pos = pblk_ppa_to_pos(geo, ppa_list[0]);

        /* If the LUN has been locked for this same request, do no attempt to
         * lock it again
         */
        if (test_and_set_bit(pos, lun_bitmap))
                return;

        __pblk_down_page(pblk, ppa_list, nr_ppas, pos);
}

void pblk_up_page(struct pblk *pblk, struct ppa_addr *ppa_list, int nr_ppas)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct pblk_lun *rlun;
        int pos = pblk_ppa_to_pos(geo, ppa_list[0]);

#ifdef CONFIG_NVM_DEBUG
        int i;

        for (i = 1; i < nr_ppas; i++)
                WARN_ON(ppa_list[0].a.lun != ppa_list[i].a.lun ||
                                ppa_list[0].a.ch != ppa_list[i].a.ch);
#endif

        rlun = &pblk->luns[pos];
        up(&rlun->wr_sem);
}

void pblk_up_rq(struct pblk *pblk, struct ppa_addr *ppa_list, int nr_ppas,
                unsigned long *lun_bitmap)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct pblk_lun *rlun;
        int num_lun = geo->all_luns;
        int bit = -1;

        while ((bit = find_next_bit(lun_bitmap, num_lun, bit + 1)) < num_lun) {
                rlun = &pblk->luns[bit];
                up(&rlun->wr_sem);
        }
}

void pblk_update_map(struct pblk *pblk, sector_t lba, struct ppa_addr ppa)
{
        struct ppa_addr ppa_l2p;

        /* logic error: lba out-of-bounds. Ignore update */
        if (!(lba < pblk->rl.nr_secs)) {
                WARN(1, "pblk: corrupted L2P map request\n");
                return;
        }

        spin_lock(&pblk->trans_lock);
        ppa_l2p = pblk_trans_map_get(pblk, lba);

        if (!pblk_addr_in_cache(ppa_l2p) && !pblk_ppa_empty(ppa_l2p))
                pblk_map_invalidate(pblk, ppa_l2p);

        pblk_trans_map_set(pblk, lba, ppa);
        spin_unlock(&pblk->trans_lock);
}

void pblk_update_map_cache(struct pblk *pblk, sector_t lba, struct ppa_addr ppa)
{

#ifdef CONFIG_NVM_DEBUG
        /* Callers must ensure that the ppa points to a cache address */
        BUG_ON(!pblk_addr_in_cache(ppa));
        BUG_ON(pblk_rb_pos_oob(&pblk->rwb, pblk_addr_to_cacheline(ppa)));
#endif

        pblk_update_map(pblk, lba, ppa);
}

int pblk_update_map_gc(struct pblk *pblk, sector_t lba, struct ppa_addr ppa_new,
                       struct pblk_line *gc_line, u64 paddr_gc)
{
        struct ppa_addr ppa_l2p, ppa_gc;
        int ret = 1;

#ifdef CONFIG_NVM_DEBUG
        /* Callers must ensure that the ppa points to a cache address */
        BUG_ON(!pblk_addr_in_cache(ppa_new));
        BUG_ON(pblk_rb_pos_oob(&pblk->rwb, pblk_addr_to_cacheline(ppa_new)));
#endif

        /* logic error: lba out-of-bounds. Ignore update */
        if (!(lba < pblk->rl.nr_secs)) {
                WARN(1, "pblk: corrupted L2P map request\n");
                return 0;
        }

        spin_lock(&pblk->trans_lock);
        ppa_l2p = pblk_trans_map_get(pblk, lba);
        ppa_gc = addr_to_gen_ppa(pblk, paddr_gc, gc_line->id);

        if (!pblk_ppa_comp(ppa_l2p, ppa_gc)) {
                spin_lock(&gc_line->lock);
                WARN(!test_bit(paddr_gc, gc_line->invalid_bitmap),
                                                "pblk: corrupted GC update");
                spin_unlock(&gc_line->lock);

                ret = 0;
                goto out;
        }

        pblk_trans_map_set(pblk, lba, ppa_new);
out:
        spin_unlock(&pblk->trans_lock);
        return ret;
}

void pblk_update_map_dev(struct pblk *pblk, sector_t lba,
                         struct ppa_addr ppa_mapped, struct ppa_addr ppa_cache)
{
        struct ppa_addr ppa_l2p;

#ifdef CONFIG_NVM_DEBUG
        /* Callers must ensure that the ppa points to a device address */
        BUG_ON(pblk_addr_in_cache(ppa_mapped));
#endif
        /* Invalidate and discard padded entries */
        if (lba == ADDR_EMPTY) {
                atomic64_inc(&pblk->pad_wa);
#ifdef CONFIG_NVM_DEBUG
                atomic_long_inc(&pblk->padded_wb);
#endif
                if (!pblk_ppa_empty(ppa_mapped))
                        pblk_map_invalidate(pblk, ppa_mapped);
                return;
        }

        /* logic error: lba out-of-bounds. Ignore update */
        if (!(lba < pblk->rl.nr_secs)) {
                WARN(1, "pblk: corrupted L2P map request\n");
                return;
        }

        spin_lock(&pblk->trans_lock);
        ppa_l2p = pblk_trans_map_get(pblk, lba);

        /* Do not update L2P if the cacheline has been updated. In this case,
         * the mapped ppa must be invalidated
         */
        if (!pblk_ppa_comp(ppa_l2p, ppa_cache)) {
                if (!pblk_ppa_empty(ppa_mapped))
                        pblk_map_invalidate(pblk, ppa_mapped);
                goto out;
        }

#ifdef CONFIG_NVM_DEBUG
        WARN_ON(!pblk_addr_in_cache(ppa_l2p) && !pblk_ppa_empty(ppa_l2p));
#endif

        pblk_trans_map_set(pblk, lba, ppa_mapped);
out:
        spin_unlock(&pblk->trans_lock);
}

void pblk_lookup_l2p_seq(struct pblk *pblk, struct ppa_addr *ppas,
                         sector_t blba, int nr_secs)
{
        int i;

        spin_lock(&pblk->trans_lock);
        for (i = 0; i < nr_secs; i++) {
                struct ppa_addr ppa;

                ppa = ppas[i] = pblk_trans_map_get(pblk, blba + i);

                /* If the L2P entry maps to a line, the reference is valid */
                if (!pblk_ppa_empty(ppa) && !pblk_addr_in_cache(ppa)) {
                        int line_id = pblk_ppa_to_line(ppa);
                        struct pblk_line *line = &pblk->lines[line_id];

                        kref_get(&line->ref);
                }
        }
        spin_unlock(&pblk->trans_lock);
}

void pblk_lookup_l2p_rand(struct pblk *pblk, struct ppa_addr *ppas,
                          u64 *lba_list, int nr_secs)
{
        u64 lba;
        int i;

        spin_lock(&pblk->trans_lock);
        for (i = 0; i < nr_secs; i++) {
                lba = lba_list[i];
                if (lba != ADDR_EMPTY) {
                        /* logic error: lba out-of-bounds. Ignore update */
                        if (!(lba < pblk->rl.nr_secs)) {
                                WARN(1, "pblk: corrupted L2P map request\n");
                                continue;
                        }
                        ppas[i] = pblk_trans_map_get(pblk, lba);
                }
        }
        spin_unlock(&pblk->trans_lock);
}