/*
 * Copyright (C) 2015 IT University of Copenhagen (rrpc.c)
 * 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.
 *
 * Implementation of a physical block-device target for Open-channel SSDs.
 *
 * pblk-init.c - pblk's initialization.
 */

#include "pblk.h"

static struct kmem_cache *pblk_ws_cache, *pblk_rec_cache, *pblk_g_rq_cache,
                                *pblk_w_rq_cache;
static DECLARE_RWSEM(pblk_lock);
struct bio_set *pblk_bio_set;

static int pblk_rw_io(struct request_queue *q, struct pblk *pblk,
                          struct bio *bio)
{
        int ret;

        /* Read requests must be <= 256kb due to NVMe's 64 bit completion bitmap
         * constraint. Writes can be of arbitrary size.
         */
        if (bio_data_dir(bio) == READ) {
                blk_queue_split(q, &bio);
                ret = pblk_submit_read(pblk, bio);
                if (ret == NVM_IO_DONE && bio_flagged(bio, BIO_CLONED))
                        bio_put(bio);

                return ret;
        }

        /* Prevent deadlock in the case of a modest LUN configuration and large
         * user I/Os. Unless stalled, the rate limiter leaves at least 256KB
         * available for user I/O.
         */
        if (pblk_get_secs(bio) > pblk_rl_max_io(&pblk->rl))
                blk_queue_split(q, &bio);

        return pblk_write_to_cache(pblk, bio, PBLK_IOTYPE_USER);
}

static blk_qc_t pblk_make_rq(struct request_queue *q, struct bio *bio)
{
        struct pblk *pblk = q->queuedata;

        if (bio_op(bio) == REQ_OP_DISCARD) {
                pblk_discard(pblk, bio);
                if (!(bio->bi_opf & REQ_PREFLUSH)) {
                        bio_endio(bio);
                        return BLK_QC_T_NONE;
                }
        }

        switch (pblk_rw_io(q, pblk, bio)) {
        case NVM_IO_ERR:
                bio_io_error(bio);
                break;
        case NVM_IO_DONE:
                bio_endio(bio);
                break;
        }

        return BLK_QC_T_NONE;
}

static size_t pblk_trans_map_size(struct pblk *pblk)
{
        int entry_size = 8;

        if (pblk->addrf_len < 32)
                entry_size = 4;

        return entry_size * pblk->rl.nr_secs;
}

#ifdef CONFIG_NVM_DEBUG
static u32 pblk_l2p_crc(struct pblk *pblk)
{
        size_t map_size;
        u32 crc = ~(u32)0;

        map_size = pblk_trans_map_size(pblk);
        crc = crc32_le(crc, pblk->trans_map, map_size);
        return crc;
}
#endif

static void pblk_l2p_free(struct pblk *pblk)
{
        vfree(pblk->trans_map);
}

static int pblk_l2p_recover(struct pblk *pblk, bool factory_init)
{
        struct pblk_line *line = NULL;

        if (factory_init) {
                pblk_setup_uuid(pblk);
        } else {
                line = pblk_recov_l2p(pblk);
                if (IS_ERR(line)) {
                        pr_err("pblk: could not recover l2p table\n");
                        return -EFAULT;
                }
        }

#ifdef CONFIG_NVM_DEBUG
        pr_info("pblk init: L2P CRC: %x\n", pblk_l2p_crc(pblk));
#endif

        /* Free full lines directly as GC has not been started yet */
        pblk_gc_free_full_lines(pblk);

        if (!line) {
                /* Configure next line for user data */
                line = pblk_line_get_first_data(pblk);
                if (!line) {
                        pr_err("pblk: line list corrupted\n");
                        return -EFAULT;
                }
        }

        return 0;
}

static int pblk_l2p_init(struct pblk *pblk, bool factory_init)
{
        sector_t i;
        struct ppa_addr ppa;
        size_t map_size;

        map_size = pblk_trans_map_size(pblk);
        pblk->trans_map = vmalloc(map_size);
        if (!pblk->trans_map)
                return -ENOMEM;

        pblk_ppa_set_empty(&ppa);

        for (i = 0; i < pblk->rl.nr_secs; i++)
                pblk_trans_map_set(pblk, i, ppa);

        return pblk_l2p_recover(pblk, factory_init);
}

static void pblk_rwb_free(struct pblk *pblk)
{
        if (pblk_rb_tear_down_check(&pblk->rwb))
                pr_err("pblk: write buffer error on tear down\n");

        pblk_rb_data_free(&pblk->rwb);
        vfree(pblk_rb_entries_ref(&pblk->rwb));
}

static int pblk_rwb_init(struct pblk *pblk)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct pblk_rb_entry *entries;
        unsigned long nr_entries;
        unsigned int power_size, power_seg_sz;

        nr_entries = pblk_rb_calculate_size(pblk->pgs_in_buffer);

        entries = vzalloc(nr_entries * sizeof(struct pblk_rb_entry));
        if (!entries)
                return -ENOMEM;

        power_size = get_count_order(nr_entries);
        power_seg_sz = get_count_order(geo->csecs);

        return pblk_rb_init(&pblk->rwb, entries, power_size, power_seg_sz);
}

/* Minimum pages needed within a lun */
#define ADDR_POOL_SIZE 64

static int pblk_set_addrf_12(struct nvm_geo *geo, struct nvm_addrf_12 *dst)
{
        struct nvm_addrf_12 *src = (struct nvm_addrf_12 *)&geo->addrf;
        int power_len;

        /* Re-calculate channel and lun format to adapt to configuration */
        power_len = get_count_order(geo->num_ch);
        if (1 << power_len != geo->num_ch) {
                pr_err("pblk: supports only power-of-two channel config.\n");
                return -EINVAL;
        }
        dst->ch_len = power_len;

        power_len = get_count_order(geo->num_lun);
        if (1 << power_len != geo->num_lun) {
                pr_err("pblk: supports only power-of-two LUN config.\n");
                return -EINVAL;
        }
        dst->lun_len = power_len;

        dst->blk_len = src->blk_len;
        dst->pg_len = src->pg_len;
        dst->pln_len = src->pln_len;
        dst->sec_len = src->sec_len;

        dst->sec_offset = 0;
        dst->pln_offset = dst->sec_len;
        dst->ch_offset = dst->pln_offset + dst->pln_len;
        dst->lun_offset = dst->ch_offset + dst->ch_len;
        dst->pg_offset = dst->lun_offset + dst->lun_len;
        dst->blk_offset = dst->pg_offset + dst->pg_len;

        dst->sec_mask = ((1ULL << dst->sec_len) - 1) << dst->sec_offset;
        dst->pln_mask = ((1ULL << dst->pln_len) - 1) << dst->pln_offset;
        dst->ch_mask = ((1ULL << dst->ch_len) - 1) << dst->ch_offset;
        dst->lun_mask = ((1ULL << dst->lun_len) - 1) << dst->lun_offset;
        dst->pg_mask = ((1ULL << dst->pg_len) - 1) << dst->pg_offset;
        dst->blk_mask = ((1ULL << dst->blk_len) - 1) << dst->blk_offset;

        return dst->blk_offset + src->blk_len;
}

static int pblk_set_addrf_20(struct nvm_geo *geo, struct nvm_addrf *adst,
                             struct pblk_addrf *udst)
{
        struct nvm_addrf *src = &geo->addrf;

        adst->ch_len = get_count_order(geo->num_ch);
        adst->lun_len = get_count_order(geo->num_lun);
        adst->chk_len = src->chk_len;
        adst->sec_len = src->sec_len;

        adst->sec_offset = 0;
        adst->ch_offset = adst->sec_len;
        adst->lun_offset = adst->ch_offset + adst->ch_len;
        adst->chk_offset = adst->lun_offset + adst->lun_len;

        adst->sec_mask = ((1ULL << adst->sec_len) - 1) << adst->sec_offset;
        adst->chk_mask = ((1ULL << adst->chk_len) - 1) << adst->chk_offset;
        adst->lun_mask = ((1ULL << adst->lun_len) - 1) << adst->lun_offset;
        adst->ch_mask = ((1ULL << adst->ch_len) - 1) << adst->ch_offset;

        udst->sec_stripe = geo->ws_opt;
        udst->ch_stripe = geo->num_ch;
        udst->lun_stripe = geo->num_lun;

        udst->sec_lun_stripe = udst->sec_stripe * udst->ch_stripe;
        udst->sec_ws_stripe = udst->sec_lun_stripe * udst->lun_stripe;

        return adst->chk_offset + adst->chk_len;
}

static int pblk_set_addrf(struct pblk *pblk)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        int mod;

        switch (geo->version) {
        case NVM_OCSSD_SPEC_12:
                div_u64_rem(geo->clba, pblk->min_write_pgs, &mod);
                if (mod) {
                        pr_err("pblk: bad configuration of sectors/pages\n");
                        return -EINVAL;
                }

                pblk->addrf_len = pblk_set_addrf_12(geo, (void *)&pblk->addrf);
                break;
        case NVM_OCSSD_SPEC_20:
                pblk->addrf_len = pblk_set_addrf_20(geo, (void *)&pblk->addrf,
                                                                &pblk->uaddrf);
                break;
        default:
                pr_err("pblk: OCSSD revision not supported (%d)\n",
                                                                geo->version);
                return -EINVAL;
        }

        return 0;
}

static int pblk_init_global_caches(struct pblk *pblk)
{
        down_write(&pblk_lock);
        pblk_ws_cache = kmem_cache_create("pblk_blk_ws",
                                sizeof(struct pblk_line_ws), 0, 0, NULL);
        if (!pblk_ws_cache) {
                up_write(&pblk_lock);
                return -ENOMEM;
        }

        pblk_rec_cache = kmem_cache_create("pblk_rec",
                                sizeof(struct pblk_rec_ctx), 0, 0, NULL);
        if (!pblk_rec_cache) {
                kmem_cache_destroy(pblk_ws_cache);
                up_write(&pblk_lock);
                return -ENOMEM;
        }

        pblk_g_rq_cache = kmem_cache_create("pblk_g_rq", pblk_g_rq_size,
                                0, 0, NULL);
        if (!pblk_g_rq_cache) {
                kmem_cache_destroy(pblk_ws_cache);
                kmem_cache_destroy(pblk_rec_cache);
                up_write(&pblk_lock);
                return -ENOMEM;
        }

        pblk_w_rq_cache = kmem_cache_create("pblk_w_rq", pblk_w_rq_size,
                                0, 0, NULL);
        if (!pblk_w_rq_cache) {
                kmem_cache_destroy(pblk_ws_cache);
                kmem_cache_destroy(pblk_rec_cache);
                kmem_cache_destroy(pblk_g_rq_cache);
                up_write(&pblk_lock);
                return -ENOMEM;
        }
        up_write(&pblk_lock);

        return 0;
}

static void pblk_free_global_caches(struct pblk *pblk)
{
        kmem_cache_destroy(pblk_ws_cache);
        kmem_cache_destroy(pblk_rec_cache);
        kmem_cache_destroy(pblk_g_rq_cache);
        kmem_cache_destroy(pblk_w_rq_cache);
}

static int pblk_core_init(struct pblk *pblk)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        int max_write_ppas;

        atomic64_set(&pblk->user_wa, 0);
        atomic64_set(&pblk->pad_wa, 0);
        atomic64_set(&pblk->gc_wa, 0);
        pblk->user_rst_wa = 0;
        pblk->pad_rst_wa = 0;
        pblk->gc_rst_wa = 0;

        atomic64_set(&pblk->nr_flush, 0);
        pblk->nr_flush_rst = 0;

        pblk->pgs_in_buffer = geo->mw_cunits * geo->all_luns;

        pblk->min_write_pgs = geo->ws_opt * (geo->csecs / PAGE_SIZE);
        max_write_ppas = pblk->min_write_pgs * geo->all_luns;
        pblk->max_write_pgs = min_t(int, max_write_ppas, NVM_MAX_VLBA);
        pblk_set_sec_per_write(pblk, pblk->min_write_pgs);

        if (pblk->max_write_pgs > PBLK_MAX_REQ_ADDRS) {
                pr_err("pblk: vector list too big(%u > %u)\n",
                                pblk->max_write_pgs, PBLK_MAX_REQ_ADDRS);
                return -EINVAL;
        }

        pblk->pad_dist = kzalloc((pblk->min_write_pgs - 1) * sizeof(atomic64_t),
                                                                GFP_KERNEL);
        if (!pblk->pad_dist)
                return -ENOMEM;

        if (pblk_init_global_caches(pblk))
                goto fail_free_pad_dist;

        /* Internal bios can be at most the sectors signaled by the device. */
        pblk->page_bio_pool = mempool_create_page_pool(NVM_MAX_VLBA, 0);
        if (!pblk->page_bio_pool)
                goto free_global_caches;

        pblk->gen_ws_pool = mempool_create_slab_pool(PBLK_GEN_WS_POOL_SIZE,
                                                        pblk_ws_cache);
        if (!pblk->gen_ws_pool)
                goto free_page_bio_pool;

        pblk->rec_pool = mempool_create_slab_pool(geo->all_luns,
                                                        pblk_rec_cache);
        if (!pblk->rec_pool)
                goto free_gen_ws_pool;

        pblk->r_rq_pool = mempool_create_slab_pool(geo->all_luns,
                                                        pblk_g_rq_cache);
        if (!pblk->r_rq_pool)
                goto free_rec_pool;

        pblk->e_rq_pool = mempool_create_slab_pool(geo->all_luns,
                                                        pblk_g_rq_cache);
        if (!pblk->e_rq_pool)
                goto free_r_rq_pool;

        pblk->w_rq_pool = mempool_create_slab_pool(geo->all_luns,
                                                        pblk_w_rq_cache);
        if (!pblk->w_rq_pool)
                goto free_e_rq_pool;

        pblk->close_wq = alloc_workqueue("pblk-close-wq",
                        WQ_MEM_RECLAIM | WQ_UNBOUND, PBLK_NR_CLOSE_JOBS);
        if (!pblk->close_wq)
                goto free_w_rq_pool;

        pblk->bb_wq = alloc_workqueue("pblk-bb-wq",
                        WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
        if (!pblk->bb_wq)
                goto free_close_wq;

        pblk->r_end_wq = alloc_workqueue("pblk-read-end-wq",
                        WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
        if (!pblk->r_end_wq)
                goto free_bb_wq;

        if (pblk_set_addrf(pblk))
                goto free_r_end_wq;

        INIT_LIST_HEAD(&pblk->compl_list);

        return 0;

free_r_end_wq:
        destroy_workqueue(pblk->r_end_wq);
free_bb_wq:
        destroy_workqueue(pblk->bb_wq);
free_close_wq:
        destroy_workqueue(pblk->close_wq);
free_w_rq_pool:
        mempool_destroy(pblk->w_rq_pool);
free_e_rq_pool:
        mempool_destroy(pblk->e_rq_pool);
free_r_rq_pool:
        mempool_destroy(pblk->r_rq_pool);
free_rec_pool:
        mempool_destroy(pblk->rec_pool);
free_gen_ws_pool:
        mempool_destroy(pblk->gen_ws_pool);
free_page_bio_pool:
        mempool_destroy(pblk->page_bio_pool);
free_global_caches:
        pblk_free_global_caches(pblk);
fail_free_pad_dist:
        kfree(pblk->pad_dist);
        return -ENOMEM;
}

static void pblk_core_free(struct pblk *pblk)
{
        if (pblk->close_wq)
                destroy_workqueue(pblk->close_wq);

        if (pblk->r_end_wq)
                destroy_workqueue(pblk->r_end_wq);

        if (pblk->bb_wq)
                destroy_workqueue(pblk->bb_wq);

        mempool_destroy(pblk->page_bio_pool);
        mempool_destroy(pblk->gen_ws_pool);
        mempool_destroy(pblk->rec_pool);
        mempool_destroy(pblk->r_rq_pool);
        mempool_destroy(pblk->e_rq_pool);
        mempool_destroy(pblk->w_rq_pool);

        pblk_free_global_caches(pblk);
        kfree(pblk->pad_dist);
}

static void pblk_line_mg_free(struct pblk *pblk)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        int i;

        kfree(l_mg->bb_template);
        kfree(l_mg->bb_aux);
        kfree(l_mg->vsc_list);

        for (i = 0; i < PBLK_DATA_LINES; i++) {
                kfree(l_mg->sline_meta[i]);
                pblk_mfree(l_mg->eline_meta[i]->buf, l_mg->emeta_alloc_type);
                kfree(l_mg->eline_meta[i]);
        }
}

static void pblk_line_meta_free(struct pblk_line *line)
{
        kfree(line->blk_bitmap);
        kfree(line->erase_bitmap);
        kfree(line->chks);
}

static void pblk_lines_free(struct pblk *pblk)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct pblk_line *line;
        int i;

        spin_lock(&l_mg->free_lock);
        for (i = 0; i < l_mg->nr_lines; i++) {
                line = &pblk->lines[i];

                pblk_line_free(pblk, line);
                pblk_line_meta_free(line);
        }
        spin_unlock(&l_mg->free_lock);

        pblk_line_mg_free(pblk);

        kfree(pblk->luns);
        kfree(pblk->lines);
}

static int pblk_bb_get_tbl(struct nvm_tgt_dev *dev, struct pblk_lun *rlun,
                           u8 *blks, int nr_blks)
{
        struct ppa_addr ppa;
        int ret;

        ppa.ppa = 0;
        ppa.g.ch = rlun->bppa.g.ch;
        ppa.g.lun = rlun->bppa.g.lun;

        ret = nvm_get_tgt_bb_tbl(dev, ppa, blks);
        if (ret)
                return ret;

        nr_blks = nvm_bb_tbl_fold(dev->parent, blks, nr_blks);
        if (nr_blks < 0)
                return -EIO;

        return 0;
}

static void *pblk_bb_get_meta(struct pblk *pblk)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        u8 *meta;
        int i, nr_blks, blk_per_lun;
        int ret;

        blk_per_lun = geo->num_chk * geo->pln_mode;
        nr_blks = blk_per_lun * geo->all_luns;

        meta = kmalloc(nr_blks, GFP_KERNEL);
        if (!meta)
                return ERR_PTR(-ENOMEM);

        for (i = 0; i < geo->all_luns; i++) {
                struct pblk_lun *rlun = &pblk->luns[i];
                u8 *meta_pos = meta + i * blk_per_lun;

                ret = pblk_bb_get_tbl(dev, rlun, meta_pos, blk_per_lun);
                if (ret) {
                        kfree(meta);
                        return ERR_PTR(-EIO);
                }
        }

        return meta;
}

static void *pblk_chunk_get_meta(struct pblk *pblk)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;

        if (geo->version == NVM_OCSSD_SPEC_12)
                return pblk_bb_get_meta(pblk);
        else
                return pblk_chunk_get_info(pblk);
}

static int pblk_luns_init(struct pblk *pblk)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct pblk_lun *rlun;
        int i;

        /* TODO: Implement unbalanced LUN support */
        if (geo->num_lun < 0) {
                pr_err("pblk: unbalanced LUN config.\n");
                return -EINVAL;
        }

        pblk->luns = kcalloc(geo->all_luns, sizeof(struct pblk_lun),
                                                                GFP_KERNEL);
        if (!pblk->luns)
                return -ENOMEM;

        for (i = 0; i < geo->all_luns; i++) {
                /* Stripe across channels */
                int ch = i % geo->num_ch;
                int lun_raw = i / geo->num_ch;
                int lunid = lun_raw + ch * geo->num_lun;

                rlun = &pblk->luns[i];
                rlun->bppa = dev->luns[lunid];

                sema_init(&rlun->wr_sem, 1);
        }

        return 0;
}

/* See comment over struct line_emeta definition */
static unsigned int calc_emeta_len(struct pblk *pblk)
{
        struct pblk_line_meta *lm = &pblk->lm;
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;

        /* Round to sector size so that lba_list starts on its own sector */
        lm->emeta_sec[1] = DIV_ROUND_UP(
                        sizeof(struct line_emeta) + lm->blk_bitmap_len +
                        sizeof(struct wa_counters), geo->csecs);
        lm->emeta_len[1] = lm->emeta_sec[1] * geo->csecs;

        /* Round to sector size so that vsc_list starts on its own sector */
        lm->dsec_per_line = lm->sec_per_line - lm->emeta_sec[0];
        lm->emeta_sec[2] = DIV_ROUND_UP(lm->dsec_per_line * sizeof(u64),
                        geo->csecs);
        lm->emeta_len[2] = lm->emeta_sec[2] * geo->csecs;

        lm->emeta_sec[3] = DIV_ROUND_UP(l_mg->nr_lines * sizeof(u32),
                        geo->csecs);
        lm->emeta_len[3] = lm->emeta_sec[3] * geo->csecs;

        lm->vsc_list_len = l_mg->nr_lines * sizeof(u32);

        return (lm->emeta_len[1] + lm->emeta_len[2] + lm->emeta_len[3]);
}

static void pblk_set_provision(struct pblk *pblk, long nr_free_blks)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct pblk_line_meta *lm = &pblk->lm;
        struct nvm_geo *geo = &dev->geo;
        sector_t provisioned;
        int sec_meta, blk_meta;

        if (geo->op == NVM_TARGET_DEFAULT_OP)
                pblk->op = PBLK_DEFAULT_OP;
        else
                pblk->op = geo->op;

        provisioned = nr_free_blks;
        provisioned *= (100 - pblk->op);
        sector_div(provisioned, 100);

        pblk->op_blks = nr_free_blks - provisioned;

        /* Internally pblk manages all free blocks, but all calculations based
         * on user capacity consider only provisioned blocks
         */
        pblk->rl.total_blocks = nr_free_blks;
        pblk->rl.nr_secs = nr_free_blks * geo->clba;

        /* Consider sectors used for metadata */
        sec_meta = (lm->smeta_sec + lm->emeta_sec[0]) * l_mg->nr_free_lines;
        blk_meta = DIV_ROUND_UP(sec_meta, geo->clba);

        pblk->capacity = (provisioned - blk_meta) * geo->clba;

        atomic_set(&pblk->rl.free_blocks, nr_free_blks);
        atomic_set(&pblk->rl.free_user_blocks, nr_free_blks);
}

static int pblk_setup_line_meta_12(struct pblk *pblk, struct pblk_line *line,
                                   void *chunk_meta)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct pblk_line_meta *lm = &pblk->lm;
        int i, chk_per_lun, nr_bad_chks = 0;

        chk_per_lun = geo->num_chk * geo->pln_mode;

        for (i = 0; i < lm->blk_per_line; i++) {
                struct pblk_lun *rlun = &pblk->luns[i];
                struct nvm_chk_meta *chunk;
                int pos = pblk_ppa_to_pos(geo, rlun->bppa);
                u8 *lun_bb_meta = chunk_meta + pos * chk_per_lun;

                chunk = &line->chks[pos];

                /*
                 * In 1.2 spec. chunk state is not persisted by the device. Thus
                 * some of the values are reset each time pblk is instantiated.
                 */
                if (lun_bb_meta[line->id] == NVM_BLK_T_FREE)
                        chunk->state =  NVM_CHK_ST_FREE;
                else
                        chunk->state = NVM_CHK_ST_OFFLINE;

                chunk->type = NVM_CHK_TP_W_SEQ;
                chunk->wi = 0;
                chunk->slba = -1;
                chunk->cnlb = geo->clba;
                chunk->wp = 0;

                if (!(chunk->state & NVM_CHK_ST_OFFLINE))
                        continue;

                set_bit(pos, line->blk_bitmap);
                nr_bad_chks++;
        }

        return nr_bad_chks;
}

static int pblk_setup_line_meta_20(struct pblk *pblk, struct pblk_line *line,
                                   struct nvm_chk_meta *meta)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct pblk_line_meta *lm = &pblk->lm;
        int i, nr_bad_chks = 0;

        for (i = 0; i < lm->blk_per_line; i++) {
                struct pblk_lun *rlun = &pblk->luns[i];
                struct nvm_chk_meta *chunk;
                struct nvm_chk_meta *chunk_meta;
                struct ppa_addr ppa;
                int pos;

                ppa = rlun->bppa;
                pos = pblk_ppa_to_pos(geo, ppa);
                chunk = &line->chks[pos];

                ppa.m.chk = line->id;
                chunk_meta = pblk_chunk_get_off(pblk, meta, ppa);

                chunk->state = chunk_meta->state;
                chunk->type = chunk_meta->type;
                chunk->wi = chunk_meta->wi;
                chunk->slba = chunk_meta->slba;
                chunk->cnlb = chunk_meta->cnlb;
                chunk->wp = chunk_meta->wp;

                if (!(chunk->state & NVM_CHK_ST_OFFLINE))
                        continue;

                if (chunk->type & NVM_CHK_TP_SZ_SPEC) {
                        WARN_ONCE(1, "pblk: custom-sized chunks unsupported\n");
                        continue;
                }

                set_bit(pos, line->blk_bitmap);
                nr_bad_chks++;
        }

        return nr_bad_chks;
}

static long pblk_setup_line_meta(struct pblk *pblk, struct pblk_line *line,
                                 void *chunk_meta, int line_id)
{
        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;
        long nr_bad_chks, chk_in_line;

        line->pblk = pblk;
        line->id = line_id;
        line->type = PBLK_LINETYPE_FREE;
        line->state = PBLK_LINESTATE_NEW;
        line->gc_group = PBLK_LINEGC_NONE;
        line->vsc = &l_mg->vsc_list[line_id];
        spin_lock_init(&line->lock);

        if (geo->version == NVM_OCSSD_SPEC_12)
                nr_bad_chks = pblk_setup_line_meta_12(pblk, line, chunk_meta);
        else
                nr_bad_chks = pblk_setup_line_meta_20(pblk, line, chunk_meta);

        chk_in_line = lm->blk_per_line - nr_bad_chks;
        if (nr_bad_chks < 0 || nr_bad_chks > lm->blk_per_line ||
                                        chk_in_line < lm->min_blk_line) {
                line->state = PBLK_LINESTATE_BAD;
                list_add_tail(&line->list, &l_mg->bad_list);
                return 0;
        }

        atomic_set(&line->blk_in_line, chk_in_line);
        list_add_tail(&line->list, &l_mg->free_list);
        l_mg->nr_free_lines++;

        return chk_in_line;
}

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

        line->blk_bitmap = kzalloc(lm->blk_bitmap_len, GFP_KERNEL);
        if (!line->blk_bitmap)
                return -ENOMEM;

        line->erase_bitmap = kzalloc(lm->blk_bitmap_len, GFP_KERNEL);
        if (!line->erase_bitmap) {
                kfree(line->blk_bitmap);
                return -ENOMEM;
        }

        line->chks = kmalloc(lm->blk_per_line * sizeof(struct nvm_chk_meta),
                                                                GFP_KERNEL);
        if (!line->chks) {
                kfree(line->erase_bitmap);
                kfree(line->blk_bitmap);
                return -ENOMEM;
        }

        return 0;
}

static int pblk_line_mg_init(struct pblk *pblk)
{
        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;
        int i, bb_distance;

        l_mg->nr_lines = geo->num_chk;
        l_mg->log_line = l_mg->data_line = NULL;
        l_mg->l_seq_nr = l_mg->d_seq_nr = 0;
        l_mg->nr_free_lines = 0;
        bitmap_zero(&l_mg->meta_bitmap, PBLK_DATA_LINES);

        INIT_LIST_HEAD(&l_mg->free_list);
        INIT_LIST_HEAD(&l_mg->corrupt_list);
        INIT_LIST_HEAD(&l_mg->bad_list);
        INIT_LIST_HEAD(&l_mg->gc_full_list);
        INIT_LIST_HEAD(&l_mg->gc_high_list);
        INIT_LIST_HEAD(&l_mg->gc_mid_list);
        INIT_LIST_HEAD(&l_mg->gc_low_list);
        INIT_LIST_HEAD(&l_mg->gc_empty_list);

        INIT_LIST_HEAD(&l_mg->emeta_list);

        l_mg->gc_lists[0] = &l_mg->gc_high_list;
        l_mg->gc_lists[1] = &l_mg->gc_mid_list;
        l_mg->gc_lists[2] = &l_mg->gc_low_list;

        spin_lock_init(&l_mg->free_lock);
        spin_lock_init(&l_mg->close_lock);
        spin_lock_init(&l_mg->gc_lock);

        l_mg->vsc_list = kcalloc(l_mg->nr_lines, sizeof(__le32), GFP_KERNEL);
        if (!l_mg->vsc_list)
                goto fail;

        l_mg->bb_template = kzalloc(lm->sec_bitmap_len, GFP_KERNEL);
        if (!l_mg->bb_template)
                goto fail_free_vsc_list;

        l_mg->bb_aux = kzalloc(lm->sec_bitmap_len, GFP_KERNEL);
        if (!l_mg->bb_aux)
                goto fail_free_bb_template;

        /* smeta is always small enough to fit on a kmalloc memory allocation,
         * emeta depends on the number of LUNs allocated to the pblk instance
         */
        for (i = 0; i < PBLK_DATA_LINES; i++) {
                l_mg->sline_meta[i] = kmalloc(lm->smeta_len, GFP_KERNEL);
                if (!l_mg->sline_meta[i])
                        goto fail_free_smeta;
        }

        /* emeta allocates three different buffers for managing metadata with
         * in-memory and in-media layouts
         */
        for (i = 0; i < PBLK_DATA_LINES; i++) {
                struct pblk_emeta *emeta;

                emeta = kmalloc(sizeof(struct pblk_emeta), GFP_KERNEL);
                if (!emeta)
                        goto fail_free_emeta;

                if (lm->emeta_len[0] > KMALLOC_MAX_CACHE_SIZE) {
                        l_mg->emeta_alloc_type = PBLK_VMALLOC_META;

                        emeta->buf = vmalloc(lm->emeta_len[0]);
                        if (!emeta->buf) {
                                kfree(emeta);
                                goto fail_free_emeta;
                        }

                        emeta->nr_entries = lm->emeta_sec[0];
                        l_mg->eline_meta[i] = emeta;
                } else {
                        l_mg->emeta_alloc_type = PBLK_KMALLOC_META;

                        emeta->buf = kmalloc(lm->emeta_len[0], GFP_KERNEL);
                        if (!emeta->buf) {
                                kfree(emeta);
                                goto fail_free_emeta;
                        }

                        emeta->nr_entries = lm->emeta_sec[0];
                        l_mg->eline_meta[i] = emeta;
                }
        }

        for (i = 0; i < l_mg->nr_lines; i++)
                l_mg->vsc_list[i] = cpu_to_le32(EMPTY_ENTRY);

        bb_distance = (geo->all_luns) * geo->ws_opt;
        for (i = 0; i < lm->sec_per_line; i += bb_distance)
                bitmap_set(l_mg->bb_template, i, geo->ws_opt);

        return 0;

fail_free_emeta:
        while (--i >= 0) {
                if (l_mg->emeta_alloc_type == PBLK_VMALLOC_META)
                        vfree(l_mg->eline_meta[i]->buf);
                else
                        kfree(l_mg->eline_meta[i]->buf);
                kfree(l_mg->eline_meta[i]);
        }
fail_free_smeta:
        for (i = 0; i < PBLK_DATA_LINES; i++)
                kfree(l_mg->sline_meta[i]);
        kfree(l_mg->bb_aux);
fail_free_bb_template:
        kfree(l_mg->bb_template);
fail_free_vsc_list:
        kfree(l_mg->vsc_list);
fail:
        return -ENOMEM;
}

static int pblk_line_meta_init(struct pblk *pblk)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct pblk_line_meta *lm = &pblk->lm;
        unsigned int smeta_len, emeta_len;
        int i;

        lm->sec_per_line = geo->clba * geo->all_luns;
        lm->blk_per_line = geo->all_luns;
        lm->blk_bitmap_len = BITS_TO_LONGS(geo->all_luns) * sizeof(long);
        lm->sec_bitmap_len = BITS_TO_LONGS(lm->sec_per_line) * sizeof(long);
        lm->lun_bitmap_len = BITS_TO_LONGS(geo->all_luns) * sizeof(long);
        lm->mid_thrs = lm->sec_per_line / 2;
        lm->high_thrs = lm->sec_per_line / 4;
        lm->meta_distance = (geo->all_luns / 2) * pblk->min_write_pgs;

        /* Calculate necessary pages for smeta. See comment over struct
         * line_smeta definition
         */
        i = 1;
add_smeta_page:
        lm->smeta_sec = i * geo->ws_opt;
        lm->smeta_len = lm->smeta_sec * geo->csecs;

        smeta_len = sizeof(struct line_smeta) + lm->lun_bitmap_len;
        if (smeta_len > lm->smeta_len) {
                i++;
                goto add_smeta_page;
        }

        /* Calculate necessary pages for emeta. See comment over struct
         * line_emeta definition
         */
        i = 1;
add_emeta_page:
        lm->emeta_sec[0] = i * geo->ws_opt;
        lm->emeta_len[0] = lm->emeta_sec[0] * geo->csecs;

        emeta_len = calc_emeta_len(pblk);
        if (emeta_len > lm->emeta_len[0]) {
                i++;
                goto add_emeta_page;
        }

        lm->emeta_bb = geo->all_luns > i ? geo->all_luns - i : 0;

        lm->min_blk_line = 1;
        if (geo->all_luns > 1)
                lm->min_blk_line += DIV_ROUND_UP(lm->smeta_sec +
                                        lm->emeta_sec[0], geo->clba);

        if (lm->min_blk_line > lm->blk_per_line) {
                pr_err("pblk: config. not supported. Min. LUN in line:%d\n",
                                                        lm->blk_per_line);

                return -EINVAL;
        }

        return 0;
}

static int pblk_lines_init(struct pblk *pblk)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct pblk_line *line;
        void *chunk_meta;
        long nr_free_chks = 0;
        int i, ret;

        ret = pblk_line_meta_init(pblk);
        if (ret)
                return ret;

        ret = pblk_line_mg_init(pblk);
        if (ret)
                return ret;

        ret = pblk_luns_init(pblk);
        if (ret)
                goto fail_free_meta;

        chunk_meta = pblk_chunk_get_meta(pblk);
        if (IS_ERR(chunk_meta)) {
                ret = PTR_ERR(chunk_meta);
                goto fail_free_luns;
        }

        pblk->lines = kcalloc(l_mg->nr_lines, sizeof(struct pblk_line),
                                                                GFP_KERNEL);
        if (!pblk->lines) {
                ret = -ENOMEM;
                goto fail_free_chunk_meta;
        }

        for (i = 0; i < l_mg->nr_lines; i++) {
                line = &pblk->lines[i];

                ret = pblk_alloc_line_meta(pblk, line);
                if (ret)
                        goto fail_free_lines;

                nr_free_chks += pblk_setup_line_meta(pblk, line, chunk_meta, i);
        }

        pblk_set_provision(pblk, nr_free_chks);

        kfree(chunk_meta);
        return 0;

fail_free_lines:
        while (--i >= 0)
                pblk_line_meta_free(&pblk->lines[i]);
        kfree(pblk->lines);
fail_free_chunk_meta:
        kfree(chunk_meta);
fail_free_luns:
        kfree(pblk->luns);
fail_free_meta:
        pblk_line_mg_free(pblk);

        return ret;
}

static int pblk_writer_init(struct pblk *pblk)
{
        pblk->writer_ts = kthread_create(pblk_write_ts, pblk, "pblk-writer-t");
        if (IS_ERR(pblk->writer_ts)) {
                int err = PTR_ERR(pblk->writer_ts);

                if (err != -EINTR)
                        pr_err("pblk: could not allocate writer kthread (%d)\n",
                                        err);
                return err;
        }

        timer_setup(&pblk->wtimer, pblk_write_timer_fn, 0);
        mod_timer(&pblk->wtimer, jiffies + msecs_to_jiffies(100));

        return 0;
}

static void pblk_writer_stop(struct pblk *pblk)
{
        /* The pipeline must be stopped and the write buffer emptied before the
         * write thread is stopped
         */
        WARN(pblk_rb_read_count(&pblk->rwb),
                        "Stopping not fully persisted write buffer\n");

        WARN(pblk_rb_sync_count(&pblk->rwb),
                        "Stopping not fully synced write buffer\n");

        del_timer_sync(&pblk->wtimer);
        if (pblk->writer_ts)
                kthread_stop(pblk->writer_ts);
}

static void pblk_free(struct pblk *pblk)
{
        pblk_lines_free(pblk);
        pblk_l2p_free(pblk);
        pblk_rwb_free(pblk);
        pblk_core_free(pblk);

        kfree(pblk);
}

static void pblk_tear_down(struct pblk *pblk)
{
        pblk_pipeline_stop(pblk);
        pblk_writer_stop(pblk);
        pblk_rb_sync_l2p(&pblk->rwb);
        pblk_rl_free(&pblk->rl);

        pr_debug("pblk: consistent tear down\n");
}

static void pblk_exit(void *private)
{
        struct pblk *pblk = private;

        down_write(&pblk_lock);
        pblk_gc_exit(pblk);
        pblk_tear_down(pblk);

#ifdef CONFIG_NVM_DEBUG
        pr_info("pblk exit: L2P CRC: %x\n", pblk_l2p_crc(pblk));
#endif

        pblk_free(pblk);
        up_write(&pblk_lock);
}

static sector_t pblk_capacity(void *private)
{
        struct pblk *pblk = private;

        return pblk->capacity * NR_PHY_IN_LOG;
}

static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk,
                       int flags)
{
        struct nvm_geo *geo = &dev->geo;
        struct request_queue *bqueue = dev->q;
        struct request_queue *tqueue = tdisk->queue;
        struct pblk *pblk;
        int ret;

        /* pblk supports 1.2 and 2.0 versions */
        if (!(geo->version == NVM_OCSSD_SPEC_12 ||
                                        geo->version == NVM_OCSSD_SPEC_20)) {
                pr_err("pblk: OCSSD version not supported (%u)\n",
                                                        geo->version);
                return ERR_PTR(-EINVAL);
        }

        if (geo->version == NVM_OCSSD_SPEC_12 && geo->dom & NVM_RSP_L2P) {
                pr_err("pblk: host-side L2P table not supported. (%x)\n",
                                                        geo->dom);
                return ERR_PTR(-EINVAL);
        }

        pblk = kzalloc(sizeof(struct pblk), GFP_KERNEL);
        if (!pblk)
                return ERR_PTR(-ENOMEM);

        pblk->dev = dev;
        pblk->disk = tdisk;
        pblk->state = PBLK_STATE_RUNNING;
        pblk->gc.gc_enabled = 0;

        spin_lock_init(&pblk->trans_lock);
        spin_lock_init(&pblk->lock);

#ifdef CONFIG_NVM_DEBUG
        atomic_long_set(&pblk->inflight_writes, 0);
        atomic_long_set(&pblk->padded_writes, 0);
        atomic_long_set(&pblk->padded_wb, 0);
        atomic_long_set(&pblk->req_writes, 0);
        atomic_long_set(&pblk->sub_writes, 0);
        atomic_long_set(&pblk->sync_writes, 0);
        atomic_long_set(&pblk->inflight_reads, 0);
        atomic_long_set(&pblk->cache_reads, 0);
        atomic_long_set(&pblk->sync_reads, 0);
        atomic_long_set(&pblk->recov_writes, 0);
        atomic_long_set(&pblk->recov_writes, 0);
        atomic_long_set(&pblk->recov_gc_writes, 0);
        atomic_long_set(&pblk->recov_gc_reads, 0);
#endif

        atomic_long_set(&pblk->read_failed, 0);
        atomic_long_set(&pblk->read_empty, 0);
        atomic_long_set(&pblk->read_high_ecc, 0);
        atomic_long_set(&pblk->read_failed_gc, 0);
        atomic_long_set(&pblk->write_failed, 0);
        atomic_long_set(&pblk->erase_failed, 0);

        ret = pblk_core_init(pblk);
        if (ret) {
                pr_err("pblk: could not initialize core\n");
                goto fail;
        }

        ret = pblk_lines_init(pblk);
        if (ret) {
                pr_err("pblk: could not initialize lines\n");
                goto fail_free_core;
        }

        ret = pblk_rwb_init(pblk);
        if (ret) {
                pr_err("pblk: could not initialize write buffer\n");
                goto fail_free_lines;
        }

        ret = pblk_l2p_init(pblk, flags & NVM_TARGET_FACTORY);
        if (ret) {
                pr_err("pblk: could not initialize maps\n");
                goto fail_free_rwb;
        }

        ret = pblk_writer_init(pblk);
        if (ret) {
                if (ret != -EINTR)
                        pr_err("pblk: could not initialize write thread\n");
                goto fail_free_l2p;
        }

        ret = pblk_gc_init(pblk);
        if (ret) {
                pr_err("pblk: could not initialize gc\n");
                goto fail_stop_writer;
        }

        /* inherit the size from the underlying device */
        blk_queue_logical_block_size(tqueue, queue_physical_block_size(bqueue));
        blk_queue_max_hw_sectors(tqueue, queue_max_hw_sectors(bqueue));

        blk_queue_write_cache(tqueue, true, false);

        tqueue->limits.discard_granularity = geo->clba * geo->csecs;
        tqueue->limits.discard_alignment = 0;
        blk_queue_max_discard_sectors(tqueue, UINT_MAX >> 9);
        blk_queue_flag_set(QUEUE_FLAG_DISCARD, tqueue);

        pr_info("pblk(%s): luns:%u, lines:%d, secs:%llu, buf entries:%u\n",
                        tdisk->disk_name,
                        geo->all_luns, pblk->l_mg.nr_lines,
                        (unsigned long long)pblk->rl.nr_secs,
                        pblk->rwb.nr_entries);

        wake_up_process(pblk->writer_ts);

        /* Check if we need to start GC */
        pblk_gc_should_kick(pblk);

        return pblk;

fail_stop_writer:
        pblk_writer_stop(pblk);
fail_free_l2p:
        pblk_l2p_free(pblk);
fail_free_rwb:
        pblk_rwb_free(pblk);
fail_free_lines:
        pblk_lines_free(pblk);
fail_free_core:
        pblk_core_free(pblk);
fail:
        kfree(pblk);
        return ERR_PTR(ret);
}

/* physical block device target */
static struct nvm_tgt_type tt_pblk = {
        .name           = "pblk",
        .version        = {1, 0, 0},

        .make_rq        = pblk_make_rq,
        .capacity       = pblk_capacity,

        .init           = pblk_init,
        .exit           = pblk_exit,

        .sysfs_init     = pblk_sysfs_init,
        .sysfs_exit     = pblk_sysfs_exit,
        .owner          = THIS_MODULE,
};

static int __init pblk_module_init(void)
{
        int ret;

        pblk_bio_set = bioset_create(BIO_POOL_SIZE, 0, 0);
        if (!pblk_bio_set)
                return -ENOMEM;
        ret = nvm_register_tgt_type(&tt_pblk);
        if (ret)
                bioset_free(pblk_bio_set);
        return ret;
}

static void pblk_module_exit(void)
{
        bioset_free(pblk_bio_set);
        nvm_unregister_tgt_type(&tt_pblk);
}

module_init(pblk_module_init);
module_exit(pblk_module_exit);
MODULE_AUTHOR("Javier Gonzalez <javier@cnexlabs.com>");
MODULE_AUTHOR("Matias Bjorling <matias@cnexlabs.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Physical Block-Device for Open-Channel SSDs");