// SPDX-License-Identifier: GPL-2.0
/*
 * 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"
#include "pblk-trace.h"

static unsigned int write_buffer_size;

module_param(write_buffer_size, uint, 0644);
MODULE_PARM_DESC(write_buffer_size, "number of entries in a write buffer");

struct pblk_global_caches {
        struct kmem_cache       *ws;
        struct kmem_cache       *rec;
        struct kmem_cache       *g_rq;
        struct kmem_cache       *w_rq;

        struct kref             kref;

        struct mutex            mutex; /* Ensures consistency between
                                        * caches and kref
                                        */
};

static struct pblk_global_caches pblk_caches = {
        .mutex = __MUTEX_INITIALIZER(pblk_caches.mutex),
        .kref = KREF_INIT(0),
};

struct bio_set pblk_bio_set;

static blk_qc_t pblk_submit_bio(struct bio *bio)
{
        struct pblk *pblk = bio->bi_bdev->bd_disk->queue->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;
                }
        }

        /* 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(&bio);
                pblk_submit_read(pblk, bio);
        } else {
                /* 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(&bio);

                pblk_write_to_cache(pblk, bio, PBLK_IOTYPE_USER);
        }

        return BLK_QC_T_NONE;
}

static const struct block_device_operations pblk_bops = {
        .owner          = THIS_MODULE,
        .submit_bio     = pblk_submit_bio,
};


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->capacity;
}

#ifdef CONFIG_NVM_PBLK_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) {
                guid_gen(&pblk->instance_uuid);
        } else {
                line = pblk_recov_l2p(pblk);
                if (IS_ERR(line)) {
                        pblk_err(pblk, "could not recover l2p table\n");
                        return -EFAULT;
                }
        }

#ifdef CONFIG_NVM_PBLK_DEBUG
        pblk_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)
                        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;
        int ret = 0;

        map_size = pblk_trans_map_size(pblk);
        pblk->trans_map = __vmalloc(map_size, GFP_KERNEL | __GFP_NOWARN |
                                    __GFP_RETRY_MAYFAIL | __GFP_HIGHMEM);
        if (!pblk->trans_map) {
                pblk_err(pblk, "failed to allocate L2P (need %zu of memory)\n",
                                map_size);
                return -ENOMEM;
        }

        pblk_ppa_set_empty(&ppa);

        for (i = 0; i < pblk->capacity; i++)
                pblk_trans_map_set(pblk, i, ppa);

        ret = pblk_l2p_recover(pblk, factory_init);
        if (ret)
                vfree(pblk->trans_map);

        return ret;
}

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

        pblk_rb_free(&pblk->rwb);
}

static int pblk_rwb_init(struct pblk *pblk)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        unsigned long buffer_size;
        int pgs_in_buffer, threshold;

        threshold = geo->mw_cunits * geo->all_luns;
        pgs_in_buffer = (max(geo->mw_cunits, geo->ws_opt) + geo->ws_opt)
                                                                * geo->all_luns;

        if (write_buffer_size && (write_buffer_size > pgs_in_buffer))
                buffer_size = write_buffer_size;
        else
                buffer_size = pgs_in_buffer;

        return pblk_rb_init(&pblk->rwb, buffer_size, threshold, geo->csecs);
}

static int pblk_set_addrf_12(struct pblk *pblk, 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) {
                pblk_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) {
                pblk_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) {
                        pblk_err(pblk, "bad configuration of sectors/pages\n");
                        return -EINVAL;
                }

                pblk->addrf_len = pblk_set_addrf_12(pblk, 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:
                pblk_err(pblk, "OCSSD revision not supported (%d)\n",
                                                                geo->version);
                return -EINVAL;
        }

        return 0;
}

static int pblk_create_global_caches(void)
{

        pblk_caches.ws = kmem_cache_create("pblk_blk_ws",
                                sizeof(struct pblk_line_ws), 0, 0, NULL);
        if (!pblk_caches.ws)
                return -ENOMEM;

        pblk_caches.rec = kmem_cache_create("pblk_rec",
                                sizeof(struct pblk_rec_ctx), 0, 0, NULL);
        if (!pblk_caches.rec)
                goto fail_destroy_ws;

        pblk_caches.g_rq = kmem_cache_create("pblk_g_rq", pblk_g_rq_size,
                                0, 0, NULL);
        if (!pblk_caches.g_rq)
                goto fail_destroy_rec;

        pblk_caches.w_rq = kmem_cache_create("pblk_w_rq", pblk_w_rq_size,
                                0, 0, NULL);
        if (!pblk_caches.w_rq)
                goto fail_destroy_g_rq;

        return 0;

fail_destroy_g_rq:
        kmem_cache_destroy(pblk_caches.g_rq);
fail_destroy_rec:
        kmem_cache_destroy(pblk_caches.rec);
fail_destroy_ws:
        kmem_cache_destroy(pblk_caches.ws);

        return -ENOMEM;
}

static int pblk_get_global_caches(void)
{
        int ret = 0;

        mutex_lock(&pblk_caches.mutex);

        if (kref_get_unless_zero(&pblk_caches.kref))
                goto out;

        ret = pblk_create_global_caches();
        if (!ret)
                kref_init(&pblk_caches.kref);

out:
        mutex_unlock(&pblk_caches.mutex);
        return ret;
}

static void pblk_destroy_global_caches(struct kref *ref)
{
        struct pblk_global_caches *c;

        c = container_of(ref, struct pblk_global_caches, kref);

        kmem_cache_destroy(c->ws);
        kmem_cache_destroy(c->rec);
        kmem_cache_destroy(c->g_rq);
        kmem_cache_destroy(c->w_rq);
}

static void pblk_put_global_caches(void)
{
        mutex_lock(&pblk_caches.mutex);
        kref_put(&pblk_caches.kref, pblk_destroy_global_caches);
        mutex_unlock(&pblk_caches.mutex);
}

static int pblk_core_init(struct pblk *pblk)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        int ret, 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->min_write_pgs = geo->ws_opt;
        pblk->min_write_pgs_data = pblk->min_write_pgs;
        max_write_ppas = pblk->min_write_pgs * geo->all_luns;
        pblk->max_write_pgs = min_t(int, max_write_ppas, NVM_MAX_VLBA);
        pblk->max_write_pgs = min_t(int, pblk->max_write_pgs,
                queue_max_hw_sectors(dev->q) / (geo->csecs >> SECTOR_SHIFT));
        pblk_set_sec_per_write(pblk, pblk->min_write_pgs);

        pblk->oob_meta_size = geo->sos;
        if (!pblk_is_oob_meta_supported(pblk)) {
                /* For drives which does not have OOB metadata feature
                 * in order to support recovery feature we need to use
                 * so called packed metadata. Packed metada will store
                 * the same information as OOB metadata (l2p table mapping,
                 * but in the form of the single page at the end of
                 * every write request.
                 */
                if (pblk->min_write_pgs
                        * sizeof(struct pblk_sec_meta) > PAGE_SIZE) {
                        /* We want to keep all the packed metadata on single
                         * page per write requests. So we need to ensure that
                         * it will fit.
                         *
                         * This is more like sanity check, since there is
                         * no device with such a big minimal write size
                         * (above 1 metabytes).
                         */
                        pblk_err(pblk, "Not supported min write size\n");
                        return -EINVAL;
                }
                /* For packed meta approach we do some simplification.
                 * On read path we always issue requests which size
                 * equal to max_write_pgs, with all pages filled with
                 * user payload except of last one page which will be
                 * filled with packed metadata.
                 */
                pblk->max_write_pgs = pblk->min_write_pgs;
                pblk->min_write_pgs_data = pblk->min_write_pgs - 1;
        }

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

        if (pblk_get_global_caches())
                goto fail_free_pad_dist;

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

        ret = mempool_init_slab_pool(&pblk->gen_ws_pool, PBLK_GEN_WS_POOL_SIZE,
                                     pblk_caches.ws);
        if (ret)
                goto free_page_bio_pool;

        ret = mempool_init_slab_pool(&pblk->rec_pool, geo->all_luns,
                                     pblk_caches.rec);
        if (ret)
                goto free_gen_ws_pool;

        ret = mempool_init_slab_pool(&pblk->r_rq_pool, geo->all_luns,
                                     pblk_caches.g_rq);
        if (ret)
                goto free_rec_pool;

        ret = mempool_init_slab_pool(&pblk->e_rq_pool, geo->all_luns,
                                     pblk_caches.g_rq);
        if (ret)
                goto free_r_rq_pool;

        ret = mempool_init_slab_pool(&pblk->w_rq_pool, geo->all_luns,
                                     pblk_caches.w_rq);
        if (ret)
                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);
        INIT_LIST_HEAD(&pblk->resubmit_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_exit(&pblk->w_rq_pool);
free_e_rq_pool:
        mempool_exit(&pblk->e_rq_pool);
free_r_rq_pool:
        mempool_exit(&pblk->r_rq_pool);
free_rec_pool:
        mempool_exit(&pblk->rec_pool);
free_gen_ws_pool:
        mempool_exit(&pblk->gen_ws_pool);
free_page_bio_pool:
        mempool_exit(&pblk->page_bio_pool);
free_global_caches:
        pblk_put_global_caches();
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_exit(&pblk->page_bio_pool);
        mempool_exit(&pblk->gen_ws_pool);
        mempool_exit(&pblk->rec_pool);
        mempool_exit(&pblk->r_rq_pool);
        mempool_exit(&pblk->e_rq_pool);
        mempool_exit(&pblk->w_rq_pool);

        pblk_put_global_caches();
        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]);
                kvfree(l_mg->eline_meta[i]->buf);
                kfree(l_mg->eline_meta[i]);
        }

        mempool_destroy(l_mg->bitmap_pool);
        kmem_cache_destroy(l_mg->bitmap_cache);
}

static void pblk_line_meta_free(struct pblk_line_mgmt *l_mg,
                                struct pblk_line *line)
{
        struct pblk_w_err_gc *w_err_gc = line->w_err_gc;

        kfree(line->blk_bitmap);
        kfree(line->erase_bitmap);
        kfree(line->chks);

        kvfree(w_err_gc->lba_list);
        kfree(w_err_gc);
}

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

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

                pblk_line_free(line);
                pblk_line_meta_free(l_mg, line);
        }

        pblk_line_mg_free(pblk);

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

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) {
                pblk_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 int pblk_set_provision(struct pblk *pblk, int nr_free_chks)
{
        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, clba;
        int minimum;

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

        minimum = pblk_get_min_chks(pblk);
        provisioned = nr_free_chks;
        provisioned *= (100 - pblk->op);
        sector_div(provisioned, 100);

        if ((nr_free_chks - provisioned) < minimum) {
                if (geo->op != NVM_TARGET_DEFAULT_OP) {
                        pblk_err(pblk, "OP too small to create a sane instance\n");
                        return -EINTR;
                }

                /* If the user did not specify an OP value, and PBLK_DEFAULT_OP
                 * is not enough, calculate and set sane value
                 */

                provisioned = nr_free_chks - minimum;
                pblk->op =  (100 * minimum) / nr_free_chks;
                pblk_info(pblk, "Default OP insufficient, adjusting OP to %d\n",
                                pblk->op);
        }

        pblk->op_blks = nr_free_chks - provisioned;

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

        /* 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);

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

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

        return 0;
}

static int pblk_setup_line_meta_chk(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;

                trace_pblk_chunk_state(pblk_disk_name(pblk), &ppa,
                                        chunk->state);

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

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

        nr_bad_chks = pblk_setup_line_meta_chk(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)
                goto free_blk_bitmap;


        line->chks = kmalloc_array(lm->blk_per_line,
                                   sizeof(struct nvm_chk_meta), GFP_KERNEL);
        if (!line->chks)
                goto free_erase_bitmap;

        line->w_err_gc = kzalloc(sizeof(struct pblk_w_err_gc), GFP_KERNEL);
        if (!line->w_err_gc)
                goto free_chks;

        return 0;

free_chks:
        kfree(line->chks);
free_erase_bitmap:
        kfree(line->erase_bitmap);
free_blk_bitmap:
        kfree(line->blk_bitmap);
        return -ENOMEM;
}

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->gc_werr_list);

        INIT_LIST_HEAD(&l_mg->emeta_list);

        l_mg->gc_lists[0] = &l_mg->gc_werr_list;
        l_mg->gc_lists[1] = &l_mg->gc_high_list;
        l_mg->gc_lists[2] = &l_mg->gc_mid_list;
        l_mg->gc_lists[3] = &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;
        }

        l_mg->bitmap_cache = kmem_cache_create("pblk_lm_bitmap",
                        lm->sec_bitmap_len, 0, 0, NULL);
        if (!l_mg->bitmap_cache)
                goto fail_free_smeta;

        /* the bitmap pool is used for both valid and map bitmaps */
        l_mg->bitmap_pool = mempool_create_slab_pool(PBLK_DATA_LINES * 2,
                                l_mg->bitmap_cache);
        if (!l_mg->bitmap_pool)
                goto fail_destroy_bitmap_cache;

        /* 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;

                emeta->buf = kvmalloc(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) {
                kvfree(l_mg->eline_meta[i]->buf);
                kfree(l_mg->eline_meta[i]);
        }

        mempool_destroy(l_mg->bitmap_pool);
fail_destroy_bitmap_cache:
        kmem_cache_destroy(l_mg->bitmap_cache);
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) {
                pblk_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;
        int 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_get_chunk_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);

                trace_pblk_line_state(pblk_disk_name(pblk), line->id,
                                                                line->state);
        }

        if (!nr_free_chks) {
                pblk_err(pblk, "too many bad blocks prevent for sane instance\n");
                ret = -EINTR;
                goto fail_free_lines;
        }

        ret = pblk_set_provision(pblk, nr_free_chks);
        if (ret)
                goto fail_free_lines;

        vfree(chunk_meta);
        return 0;

fail_free_lines:
        while (--i >= 0)
                pblk_line_meta_free(l_mg, &pblk->lines[i]);
        kfree(pblk->lines);
fail_free_chunk_meta:
        vfree(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)
                        pblk_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, bool graceful)
{
        if (graceful)
                __pblk_pipeline_flush(pblk);
        __pblk_pipeline_stop(pblk);
        pblk_writer_stop(pblk);
        pblk_rb_sync_l2p(&pblk->rwb);
        pblk_rl_free(&pblk->rl);

        pblk_debug(pblk, "consistent tear down (graceful:%d)\n", graceful);
}

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

        pblk_gc_exit(pblk, graceful);
        pblk_tear_down(pblk, graceful);

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

        pblk_free(pblk);
}

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

        pblk->dev = dev;
        pblk->disk = tdisk;
        pblk->state = PBLK_STATE_RUNNING;
        trace_pblk_state(pblk_disk_name(pblk), pblk->state);
        pblk->gc.gc_enabled = 0;

        if (!(geo->version == NVM_OCSSD_SPEC_12 ||
                                        geo->version == NVM_OCSSD_SPEC_20)) {
                pblk_err(pblk, "OCSSD version not supported (%u)\n",
                                                        geo->version);
                kfree(pblk);
                return ERR_PTR(-EINVAL);
        }

        if (geo->ext) {
                pblk_err(pblk, "extended metadata not supported\n");
                kfree(pblk);
                return ERR_PTR(-EINVAL);
        }

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

#ifdef CONFIG_NVM_PBLK_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) {
                pblk_err(pblk, "could not initialize core\n");
                goto fail;
        }

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

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

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

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

        ret = pblk_gc_init(pblk);
        if (ret) {
                pblk_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);

        pblk_info(pblk, "luns:%u, lines:%d, secs:%llu, buf entries:%u\n",
                        geo->all_luns, pblk->l_mg.nr_lines,
                        (unsigned long long)pblk->capacity,
                        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},

        .bops           = &pblk_bops,
        .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;

        ret = bioset_init(&pblk_bio_set, BIO_POOL_SIZE, 0, 0);
        if (ret)
                return ret;
        ret = nvm_register_tgt_type(&tt_pblk);
        if (ret)
                bioset_exit(&pblk_bio_set);
        return ret;
}

static void pblk_module_exit(void)
{
        bioset_exit(&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");