/*
 * 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->ppaf_bitsize < 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_init(struct pblk *pblk)
{
        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 0;
}

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->sec_size);

        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_ppaf(struct pblk *pblk)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct nvm_addr_format ppaf = geo->ppaf;
        int power_len;

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

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

        pblk->ppaf.sec_offset = 0;
        pblk->ppaf.pln_offset = ppaf.sect_len;
        pblk->ppaf.ch_offset = pblk->ppaf.pln_offset + ppaf.pln_len;
        pblk->ppaf.lun_offset = pblk->ppaf.ch_offset + ppaf.ch_len;
        pblk->ppaf.pg_offset = pblk->ppaf.lun_offset + ppaf.lun_len;
        pblk->ppaf.blk_offset = pblk->ppaf.pg_offset + ppaf.pg_len;
        pblk->ppaf.sec_mask = (1ULL << ppaf.sect_len) - 1;
        pblk->ppaf.pln_mask = ((1ULL << ppaf.pln_len) - 1) <<
                                                        pblk->ppaf.pln_offset;
        pblk->ppaf.ch_mask = ((1ULL << ppaf.ch_len) - 1) <<
                                                        pblk->ppaf.ch_offset;
        pblk->ppaf.lun_mask = ((1ULL << ppaf.lun_len) - 1) <<
                                                        pblk->ppaf.lun_offset;
        pblk->ppaf.pg_mask = ((1ULL << ppaf.pg_len) - 1) <<
                                                        pblk->ppaf.pg_offset;
        pblk->ppaf.blk_mask = ((1ULL << ppaf.blk_len) - 1) <<
                                                        pblk->ppaf.blk_offset;

        pblk->ppaf_bitsize = pblk->ppaf.blk_offset + ppaf.blk_len;

        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;

        pblk->pgs_in_buffer = NVM_MEM_PAGE_WRITE * geo->sec_per_pg *
                                                geo->nr_planes * geo->nr_luns;

        if (pblk_init_global_caches(pblk))
                return -ENOMEM;

        /* Internal bios can be at most the sectors signaled by the device. */
        pblk->page_bio_pool = mempool_create_page_pool(nvm_max_phys_sects(dev),
                                                                        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->nr_luns, pblk_rec_cache);
        if (!pblk->rec_pool)
                goto free_gen_ws_pool;

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

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

        pblk->w_rq_pool = mempool_create_slab_pool(geo->nr_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_ppaf(pblk))
                goto free_r_end_wq;

        if (pblk_rwb_init(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);
        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);
}

static void pblk_luns_free(struct pblk *pblk)
{
        kfree(pblk->luns);
}

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

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_free_line_bitmaps(line);
        }
        spin_unlock(&l_mg->free_lock);
}

static void pblk_line_meta_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]);
        }

        kfree(pblk->lines);
}

static int pblk_bb_discovery(struct nvm_tgt_dev *dev, struct pblk_lun *rlun)
{
        struct nvm_geo *geo = &dev->geo;
        struct ppa_addr ppa;
        u8 *blks;
        int nr_blks, ret;

        nr_blks = geo->blks_per_lun * geo->plane_mode;
        blks = kmalloc(nr_blks, GFP_KERNEL);
        if (!blks)
                return -ENOMEM;

        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)
                goto out;

        nr_blks = nvm_bb_tbl_fold(dev->parent, blks, nr_blks);
        if (nr_blks < 0) {
                ret = nr_blks;
                goto out;
        }

        rlun->bb_list = blks;

        return 0;
out:
        kfree(blks);
        return ret;
}

static int pblk_bb_line(struct pblk *pblk, struct pblk_line *line,
                        int blk_per_line)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        struct pblk_lun *rlun;
        int bb_cnt = 0;
        int i;

        for (i = 0; i < blk_per_line; i++) {
                rlun = &pblk->luns[i];
                if (rlun->bb_list[line->id] == NVM_BLK_T_FREE)
                        continue;

                set_bit(pblk_ppa_to_pos(geo, rlun->bppa), line->blk_bitmap);
                bb_cnt++;
        }

        return bb_cnt;
}

static int pblk_alloc_line_bitmaps(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;
        }

        return 0;
}

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

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

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

        for (i = 0; i < geo->nr_luns; i++) {
                /* Stripe across channels */
                int ch = i % geo->nr_chnls;
                int lun_raw = i / geo->nr_chnls;
                int lunid = lun_raw + ch * geo->luns_per_chnl;

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

                sema_init(&rlun->wr_sem, 1);

                ret = pblk_bb_discovery(dev, rlun);
                if (ret) {
                        while (--i >= 0)
                                kfree(pblk->luns[i].bb_list);
                        return ret;
                }
        }

        return 0;
}

static int pblk_lines_configure(struct pblk *pblk, int flags)
{
        struct pblk_line *line = NULL;
        int ret = 0;

        if (!(flags & NVM_TARGET_FACTORY)) {
                line = pblk_recov_l2p(pblk);
                if (IS_ERR(line)) {
                        pr_err("pblk: could not recover l2p table\n");
                        ret = -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");
                        ret = -EFAULT;
                }
        }

        return ret;
}

/* 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,
                        geo->sec_size);
        lm->emeta_len[1] = lm->emeta_sec[1] * geo->sec_size;

        /* 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->sec_size);
        lm->emeta_len[2] = lm->emeta_sec[2] * geo->sec_size;

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

        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 nvm_geo *geo = &dev->geo;
        sector_t provisioned;

        pblk->over_pct = 20;

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

        /* 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->sec_per_blk;
        pblk->capacity = provisioned * geo->sec_per_blk;
        atomic_set(&pblk->rl.free_blocks, nr_free_blks);
}

static int pblk_lines_alloc_metadata(struct pblk *pblk)
{
        struct pblk_line_mgmt *l_mg = &pblk->l_mg;
        struct pblk_line_meta *lm = &pblk->lm;
        int i;

        /* 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;
                }
        }

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

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

        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]);

        return -ENOMEM;
}

static int pblk_lines_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;
        struct pblk_line *line;
        unsigned int smeta_len, emeta_len;
        long nr_bad_blks, nr_free_blks;
        int bb_distance, max_write_ppas, mod;
        int i, ret;

        pblk->min_write_pgs = geo->sec_per_pl * (geo->sec_size / PAGE_SIZE);
        max_write_ppas = pblk->min_write_pgs * geo->nr_luns;
        pblk->max_write_pgs = (max_write_ppas < nvm_max_phys_sects(dev)) ?
                                max_write_ppas : nvm_max_phys_sects(dev);
        pblk_set_sec_per_write(pblk, pblk->min_write_pgs);

        if (pblk->max_write_pgs > PBLK_MAX_REQ_ADDRS) {
                pr_err("pblk: cannot support device max_phys_sect\n");
                return -EINVAL;
        }

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

        l_mg->nr_lines = geo->blks_per_lun;
        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);

        lm->sec_per_line = geo->sec_per_blk * geo->nr_luns;
        lm->blk_per_line = geo->nr_luns;
        lm->blk_bitmap_len = BITS_TO_LONGS(geo->nr_luns) * sizeof(long);
        lm->sec_bitmap_len = BITS_TO_LONGS(lm->sec_per_line) * sizeof(long);
        lm->lun_bitmap_len = BITS_TO_LONGS(geo->nr_luns) * sizeof(long);
        lm->mid_thrs = lm->sec_per_line / 2;
        lm->high_thrs = lm->sec_per_line / 4;
        lm->meta_distance = (geo->nr_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->sec_per_pl;
        lm->smeta_len = lm->smeta_sec * geo->sec_size;

        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->sec_per_pl;
        lm->emeta_len[0] = lm->emeta_sec[0] * geo->sec_size;

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

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

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

        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);
                ret = -EINVAL;
                goto fail;
        }

        ret = pblk_lines_alloc_metadata(pblk);
        if (ret)
                goto fail;

        l_mg->bb_template = kzalloc(lm->sec_bitmap_len, GFP_KERNEL);
        if (!l_mg->bb_template) {
                ret = -ENOMEM;
                goto fail_free_meta;
        }

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

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

        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);

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

        nr_free_blks = 0;
        for (i = 0; i < l_mg->nr_lines; i++) {
                int blk_in_line;

                line = &pblk->lines[i];

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

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

                nr_bad_blks = pblk_bb_line(pblk, line, lm->blk_per_line);
                if (nr_bad_blks < 0 || nr_bad_blks > lm->blk_per_line) {
                        pblk_free_line_bitmaps(line);
                        ret = -EINVAL;
                        goto fail_free_lines;
                }

                blk_in_line = lm->blk_per_line - nr_bad_blks;
                if (blk_in_line < lm->min_blk_line) {
                        line->state = PBLK_LINESTATE_BAD;
                        list_add_tail(&line->list, &l_mg->bad_list);
                        continue;
                }

                nr_free_blks += blk_in_line;
                atomic_set(&line->blk_in_line, blk_in_line);

                l_mg->nr_free_lines++;
                list_add_tail(&line->list, &l_mg->free_list);
        }

        pblk_set_provision(pblk, nr_free_blks);

        /* Cleanup per-LUN bad block lists - managed within lines on run-time */
        for (i = 0; i < geo->nr_luns; i++)
                kfree(pblk->luns[i].bb_list);

        return 0;
fail_free_lines:
        while (--i >= 0)
                pblk_free_line_bitmaps(&pblk->lines[i]);
fail_free_bb_aux:
        kfree(l_mg->bb_aux);
fail_free_bb_template:
        kfree(l_mg->bb_template);
fail_free_meta:
        pblk_line_meta_free(pblk);
fail:
        for (i = 0; i < geo->nr_luns; i++)
                kfree(pblk->luns[i].bb_list);

        return ret;
}

static int pblk_writer_init(struct pblk *pblk)
{
        timer_setup(&pblk->wtimer, pblk_write_timer_fn, 0);
        mod_timer(&pblk->wtimer, jiffies + msecs_to_jiffies(100));

        pblk->writer_ts = kthread_create(pblk_write_ts, pblk, "pblk-writer-t");
        if (IS_ERR(pblk->writer_ts)) {
                pr_err("pblk: could not allocate writer kthread\n");
                return PTR_ERR(pblk->writer_ts);
        }

        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");

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

static void pblk_free(struct pblk *pblk)
{
        pblk_luns_free(pblk);
        pblk_lines_free(pblk);
        pblk_line_meta_free(pblk);
        pblk_core_free(pblk);
        pblk_l2p_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_rwb_free(pblk);
        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;

        if (dev->identity.dom & NVM_RSP_L2P) {
                pr_err("pblk: host-side L2P table not supported. (%x)\n",
                                                        dev->identity.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);

        if (flags & NVM_TARGET_FACTORY)
                pblk_setup_uuid(pblk);

#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->nr_flush, 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_luns_init(pblk, dev->luns);
        if (ret) {
                pr_err("pblk: could not initialize luns\n");
                goto fail;
        }

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

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

        ret = pblk_l2p_init(pblk);
        if (ret) {
                pr_err("pblk: could not initialize maps\n");
                goto fail_free_core;
        }

        ret = pblk_lines_configure(pblk, flags);
        if (ret) {
                pr_err("pblk: could not configure lines\n");
                goto fail_free_l2p;
        }

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

        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->pgs_per_blk * geo->pfpg_size;
        tqueue->limits.discard_alignment = 0;
        blk_queue_max_discard_sectors(tqueue, UINT_MAX >> 9);
        queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, tqueue);

        pr_info("pblk init: luns:%u, lines:%d, secs:%llu, buf entries:%u\n",
                        geo->nr_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_lines:
        pblk_lines_free(pblk);
fail_free_l2p:
        pblk_l2p_free(pblk);
fail_free_core:
        pblk_core_free(pblk);
fail_free_line_meta:
        pblk_line_meta_free(pblk);
fail_free_luns:
        pblk_luns_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");