// SPDX-License-Identifier: GPL-2.0-only

  /*
   * Copyright (C) 2015 IT University of Copenhagen. All rights reserved.
   * Initial release: Matias Bjorling <m@bjorling.me>

   */

  #define pr_fmt(fmt) "nvm: " fmt

  #include <linux/list.h>
  #include <linux/types.h>
  #include <linux/sem.h>
  #include <linux/bitmap.h>

  #include <linux/module.h>

  #include <linux/moduleparam.h>

  #include <linux/miscdevice.h>
  #include <linux/lightnvm.h>

  #include <linux/sched/sysctl.h>

  static LIST_HEAD(nvm_tgt_types);

  static DECLARE_RWSEM(nvm_tgtt_lock);

  static LIST_HEAD(nvm_devices);
  static DECLARE_RWSEM(nvm_lock);

  /* Map between virtual and physical channel and lun */
  struct nvm_ch_map {
  	int ch_off;

  	int num_lun;

  	int *lun_offs;
  };
  
  struct nvm_dev_map {
  	struct nvm_ch_map *chnls;

  	int num_ch;

  };

  static void nvm_free(struct kref *ref);

  static struct nvm_target *nvm_find_target(struct nvm_dev *dev, const char *name)
  {
  	struct nvm_target *tgt;
  
  	list_for_each_entry(tgt, &dev->targets, list)
  		if (!strcmp(name, tgt->disk->disk_name))
  			return tgt;
  
  	return NULL;
  }

  static bool nvm_target_exists(const char *name)
  {
  	struct nvm_dev *dev;
  	struct nvm_target *tgt;
  	bool ret = false;
  
  	down_write(&nvm_lock);
  	list_for_each_entry(dev, &nvm_devices, devices) {
  		mutex_lock(&dev->mlock);
  		list_for_each_entry(tgt, &dev->targets, list) {
  			if (!strcmp(name, tgt->disk->disk_name)) {
  				ret = true;
  				mutex_unlock(&dev->mlock);
  				goto out;
  			}
  		}
  		mutex_unlock(&dev->mlock);
  	}
  
  out:
  	up_write(&nvm_lock);
  	return ret;
  }

  static int nvm_reserve_luns(struct nvm_dev *dev, int lun_begin, int lun_end)
  {
  	int i;
  
  	for (i = lun_begin; i <= lun_end; i++) {
  		if (test_and_set_bit(i, dev->lun_map)) {

  			pr_err("lun %d already allocated
  ", i);

  			goto err;
  		}
  	}
  
  	return 0;
  err:

  	while (--i >= lun_begin)

  		clear_bit(i, dev->lun_map);
  
  	return -EBUSY;
  }
  
  static void nvm_release_luns_err(struct nvm_dev *dev, int lun_begin,
  				 int lun_end)
  {
  	int i;
  
  	for (i = lun_begin; i <= lun_end; i++)
  		WARN_ON(!test_and_clear_bit(i, dev->lun_map));
  }

  static void nvm_remove_tgt_dev(struct nvm_tgt_dev *tgt_dev, int clear)

  {
  	struct nvm_dev *dev = tgt_dev->parent;
  	struct nvm_dev_map *dev_map = tgt_dev->map;
  	int i, j;

  	for (i = 0; i < dev_map->num_ch; i++) {

  		struct nvm_ch_map *ch_map = &dev_map->chnls[i];
  		int *lun_offs = ch_map->lun_offs;
  		int ch = i + ch_map->ch_off;

  		if (clear) {

  			for (j = 0; j < ch_map->num_lun; j++) {

  				int lun = j + lun_offs[j];

  				int lunid = (ch * dev->geo.num_lun) + lun;

  				WARN_ON(!test_and_clear_bit(lunid,
  							dev->lun_map));
  			}

  		}
  
  		kfree(ch_map->lun_offs);
  	}
  
  	kfree(dev_map->chnls);
  	kfree(dev_map);
  
  	kfree(tgt_dev->luns);
  	kfree(tgt_dev);
  }
  
  static struct nvm_tgt_dev *nvm_create_tgt_dev(struct nvm_dev *dev,

  					      u16 lun_begin, u16 lun_end,
  					      u16 op)

  {
  	struct nvm_tgt_dev *tgt_dev = NULL;
  	struct nvm_dev_map *dev_rmap = dev->rmap;
  	struct nvm_dev_map *dev_map;
  	struct ppa_addr *luns;

  	int num_lun = lun_end - lun_begin + 1;
  	int luns_left = num_lun;
  	int num_ch = num_lun / dev->geo.num_lun;
  	int num_ch_mod = num_lun % dev->geo.num_lun;
  	int bch = lun_begin / dev->geo.num_lun;
  	int blun = lun_begin % dev->geo.num_lun;

  	int lunid = 0;
  	int lun_balanced = 1;

  	int sec_per_lun, prev_num_lun;

  	int i, j;

  	num_ch = (num_ch_mod == 0) ? num_ch : num_ch + 1;

  
  	dev_map = kmalloc(sizeof(struct nvm_dev_map), GFP_KERNEL);
  	if (!dev_map)
  		goto err_dev;

  	dev_map->chnls = kcalloc(num_ch, sizeof(struct nvm_ch_map), GFP_KERNEL);

  	if (!dev_map->chnls)
  		goto err_chnls;

  	luns = kcalloc(num_lun, sizeof(struct ppa_addr), GFP_KERNEL);

  	if (!luns)
  		goto err_luns;

  	prev_num_lun = (luns_left > dev->geo.num_lun) ?
  					dev->geo.num_lun : luns_left;
  	for (i = 0; i < num_ch; i++) {

  		struct nvm_ch_map *ch_rmap = &dev_rmap->chnls[i + bch];
  		int *lun_roffs = ch_rmap->lun_offs;
  		struct nvm_ch_map *ch_map = &dev_map->chnls[i];
  		int *lun_offs;

  		int luns_in_chnl = (luns_left > dev->geo.num_lun) ?
  					dev->geo.num_lun : luns_left;

  		if (lun_balanced && prev_num_lun != luns_in_chnl)

  			lun_balanced = 0;
  
  		ch_map->ch_off = ch_rmap->ch_off = bch;

  		ch_map->num_lun = luns_in_chnl;

  
  		lun_offs = kcalloc(luns_in_chnl, sizeof(int), GFP_KERNEL);
  		if (!lun_offs)
  			goto err_ch;
  
  		for (j = 0; j < luns_in_chnl; j++) {
  			luns[lunid].ppa = 0;

  			luns[lunid].a.ch = i;
  			luns[lunid++].a.lun = j;

  
  			lun_offs[j] = blun;
  			lun_roffs[j + blun] = blun;
  		}
  
  		ch_map->lun_offs = lun_offs;
  
  		/* when starting a new channel, lun offset is reset */
  		blun = 0;
  		luns_left -= luns_in_chnl;
  	}

  	dev_map->num_ch = num_ch;

  
  	tgt_dev = kmalloc(sizeof(struct nvm_tgt_dev), GFP_KERNEL);
  	if (!tgt_dev)
  		goto err_ch;

  	/* Inherit device geometry from parent */

  	memcpy(&tgt_dev->geo, &dev->geo, sizeof(struct nvm_geo));

  	/* Target device only owns a portion of the physical device */

  	tgt_dev->geo.num_ch = num_ch;
  	tgt_dev->geo.num_lun = (lun_balanced) ? prev_num_lun : -1;
  	tgt_dev->geo.all_luns = num_lun;
  	tgt_dev->geo.all_chunks = num_lun * dev->geo.num_chk;

  	tgt_dev->geo.op = op;

  	sec_per_lun = dev->geo.clba * dev->geo.num_chk;
  	tgt_dev->geo.total_secs = num_lun * sec_per_lun;

  	tgt_dev->q = dev->q;
  	tgt_dev->map = dev_map;
  	tgt_dev->luns = luns;

  	tgt_dev->parent = dev;
  
  	return tgt_dev;
  err_ch:

  	while (--i >= 0)

  		kfree(dev_map->chnls[i].lun_offs);
  	kfree(luns);
  err_luns:
  	kfree(dev_map->chnls);
  err_chnls:
  	kfree(dev_map);
  err_dev:
  	return tgt_dev;
  }

  static struct nvm_tgt_type *__nvm_find_target_type(const char *name)

  {

  	struct nvm_tgt_type *tt;

  	list_for_each_entry(tt, &nvm_tgt_types, list)
  		if (!strcmp(name, tt->name))
  			return tt;

  	return NULL;
  }
  
  static struct nvm_tgt_type *nvm_find_target_type(const char *name)
  {
  	struct nvm_tgt_type *tt;
  
  	down_write(&nvm_tgtt_lock);
  	tt = __nvm_find_target_type(name);
  	up_write(&nvm_tgtt_lock);

  	return tt;
  }

  static int nvm_config_check_luns(struct nvm_geo *geo, int lun_begin,
  				 int lun_end)
  {
  	if (lun_begin > lun_end || lun_end >= geo->all_luns) {

  		pr_err("lun out of bound (%u:%u > %u)
  ",

  			lun_begin, lun_end, geo->all_luns - 1);
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static int __nvm_config_simple(struct nvm_dev *dev,
  			       struct nvm_ioctl_create_simple *s)
  {
  	struct nvm_geo *geo = &dev->geo;
  
  	if (s->lun_begin == -1 && s->lun_end == -1) {
  		s->lun_begin = 0;
  		s->lun_end = geo->all_luns - 1;
  	}
  
  	return nvm_config_check_luns(geo, s->lun_begin, s->lun_end);
  }
  
  static int __nvm_config_extended(struct nvm_dev *dev,
  				 struct nvm_ioctl_create_extended *e)
  {

  	if (e->lun_begin == 0xFFFF && e->lun_end == 0xFFFF) {
  		e->lun_begin = 0;
  		e->lun_end = dev->geo.all_luns - 1;
  	}
  
  	/* op not set falls into target's default */

  	if (e->op == 0xFFFF) {

  		e->op = NVM_TARGET_DEFAULT_OP;

  	} else if (e->op < NVM_TARGET_MIN_OP || e->op > NVM_TARGET_MAX_OP) {

  		pr_err("invalid over provisioning value
  ");

  		return -EINVAL;
  	}

  	return nvm_config_check_luns(&dev->geo, e->lun_begin, e->lun_end);

  }

  static int nvm_create_tgt(struct nvm_dev *dev, struct nvm_ioctl_create *create)
  {

  	struct nvm_ioctl_create_extended e;

  	struct request_queue *tqueue;
  	struct gendisk *tdisk;
  	struct nvm_tgt_type *tt;
  	struct nvm_target *t;
  	struct nvm_tgt_dev *tgt_dev;
  	void *targetdata;

  	unsigned int mdts;

  	int ret;

  	switch (create->conf.type) {
  	case NVM_CONFIG_TYPE_SIMPLE:
  		ret = __nvm_config_simple(dev, &create->conf.s);
  		if (ret)
  			return ret;
  
  		e.lun_begin = create->conf.s.lun_begin;
  		e.lun_end = create->conf.s.lun_end;
  		e.op = NVM_TARGET_DEFAULT_OP;
  		break;
  	case NVM_CONFIG_TYPE_EXTENDED:
  		ret = __nvm_config_extended(dev, &create->conf.e);
  		if (ret)
  			return ret;
  
  		e = create->conf.e;
  		break;
  	default:

  		pr_err("config type not valid
  ");

  		return -EINVAL;
  	}

  	tt = nvm_find_target_type(create->tgttype);

  	if (!tt) {

  		pr_err("target type %s not found
  ", create->tgttype);

  		return -EINVAL;
  	}

  	if ((tt->flags & NVM_TGT_F_HOST_L2P) != (dev->geo.dom & NVM_RSP_L2P)) {

  		pr_err("device is incompatible with target L2P type.
  ");

  		return -EINVAL;
  	}

  	if (nvm_target_exists(create->tgtname)) {

  		pr_err("target name already exists (%s)
  ",

  							create->tgtname);

  		return -EINVAL;
  	}

  	ret = nvm_reserve_luns(dev, e.lun_begin, e.lun_end);

  	if (ret)
  		return ret;

  
  	t = kmalloc(sizeof(struct nvm_target), GFP_KERNEL);

  	if (!t) {
  		ret = -ENOMEM;

  		goto err_reserve;

  	}

  	tgt_dev = nvm_create_tgt_dev(dev, e.lun_begin, e.lun_end, e.op);

  	if (!tgt_dev) {

  		pr_err("could not create target device
  ");

  		ret = -ENOMEM;

  		goto err_t;
  	}

  	tdisk = alloc_disk(0);

  	if (!tdisk) {
  		ret = -ENOMEM;

  		goto err_dev;

  	}

  	tqueue = blk_alloc_queue(dev->q->node);

  	if (!tqueue) {
  		ret = -ENOMEM;

  		goto err_disk;

  	}

  	strlcpy(tdisk->disk_name, create->tgtname, sizeof(tdisk->disk_name));

  	tdisk->flags = GENHD_FL_EXT_DEVT;
  	tdisk->major = 0;
  	tdisk->first_minor = 0;

  	tdisk->fops = tt->bops;

  	tdisk->queue = tqueue;

  	targetdata = tt->init(tgt_dev, tdisk, create->flags);

  	if (IS_ERR(targetdata)) {
  		ret = PTR_ERR(targetdata);

  		goto err_init;

  	}

  
  	tdisk->private_data = targetdata;
  	tqueue->queuedata = targetdata;

  	mdts = (dev->geo.csecs >> 9) * NVM_MAX_VLBA;
  	if (dev->geo.mdts) {
  		mdts = min_t(u32, dev->geo.mdts,
  				(dev->geo.csecs >> 9) * NVM_MAX_VLBA);
  	}
  	blk_queue_max_hw_sectors(tqueue, mdts);

  
  	set_capacity(tdisk, tt->capacity(targetdata));
  	add_disk(tdisk);

  	if (tt->sysfs_init && tt->sysfs_init(tdisk)) {
  		ret = -ENOMEM;

  		goto err_sysfs;

  	}

  	t->type = tt;
  	t->disk = tdisk;
  	t->dev = tgt_dev;
  
  	mutex_lock(&dev->mlock);
  	list_add_tail(&t->list, &dev->targets);
  	mutex_unlock(&dev->mlock);

  	__module_get(tt->owner);

  	return 0;

  err_sysfs:
  	if (tt->exit)

  		tt->exit(targetdata, true);

  err_init:

  	blk_cleanup_queue(tqueue);

  	tdisk->queue = NULL;

  err_disk:
  	put_disk(tdisk);

  err_dev:

  	nvm_remove_tgt_dev(tgt_dev, 0);

  err_t:
  	kfree(t);
  err_reserve:

  	nvm_release_luns_err(dev, e.lun_begin, e.lun_end);

  	return ret;

  }

  static void __nvm_remove_target(struct nvm_target *t, bool graceful)

  {
  	struct nvm_tgt_type *tt = t->type;
  	struct gendisk *tdisk = t->disk;
  	struct request_queue *q = tdisk->queue;
  
  	del_gendisk(tdisk);
  	blk_cleanup_queue(q);

  	if (tt->sysfs_exit)
  		tt->sysfs_exit(tdisk);

  	if (tt->exit)

  		tt->exit(tdisk->private_data, graceful);

  	nvm_remove_tgt_dev(t->dev, 1);

  	put_disk(tdisk);

  	module_put(t->type->owner);

  
  	list_del(&t->list);
  	kfree(t);
  }
  
  /**
   * nvm_remove_tgt - Removes a target from the media manager

   * @remove:	ioctl structure with target name to remove.
   *
   * Returns:
   * 0: on success
   * 1: on not found
   * <0: on error
   */

  static int nvm_remove_tgt(struct nvm_ioctl_remove *remove)

  {

  	struct nvm_target *t = NULL;

  	struct nvm_dev *dev;

  	down_read(&nvm_lock);
  	list_for_each_entry(dev, &nvm_devices, devices) {
  		mutex_lock(&dev->mlock);
  		t = nvm_find_target(dev, remove->tgtname);
  		if (t) {
  			mutex_unlock(&dev->mlock);
  			break;
  		}

  		mutex_unlock(&dev->mlock);

  	}

  	up_read(&nvm_lock);

  	if (!t) {
  		pr_err("failed to remove target %s
  ",
  				remove->tgtname);

  		return 1;

  	}

  	__nvm_remove_target(t, true);

  	kref_put(&dev->ref, nvm_free);

  
  	return 0;
  }
  
  static int nvm_register_map(struct nvm_dev *dev)
  {
  	struct nvm_dev_map *rmap;
  	int i, j;
  
  	rmap = kmalloc(sizeof(struct nvm_dev_map), GFP_KERNEL);
  	if (!rmap)
  		goto err_rmap;

  	rmap->chnls = kcalloc(dev->geo.num_ch, sizeof(struct nvm_ch_map),

  								GFP_KERNEL);
  	if (!rmap->chnls)
  		goto err_chnls;

  	for (i = 0; i < dev->geo.num_ch; i++) {

  		struct nvm_ch_map *ch_rmap;
  		int *lun_roffs;

  		int luns_in_chnl = dev->geo.num_lun;

  
  		ch_rmap = &rmap->chnls[i];
  
  		ch_rmap->ch_off = -1;

  		ch_rmap->num_lun = luns_in_chnl;

  
  		lun_roffs = kcalloc(luns_in_chnl, sizeof(int), GFP_KERNEL);
  		if (!lun_roffs)
  			goto err_ch;
  
  		for (j = 0; j < luns_in_chnl; j++)
  			lun_roffs[j] = -1;
  
  		ch_rmap->lun_offs = lun_roffs;
  	}
  
  	dev->rmap = rmap;
  
  	return 0;
  err_ch:
  	while (--i >= 0)
  		kfree(rmap->chnls[i].lun_offs);
  err_chnls:
  	kfree(rmap);
  err_rmap:
  	return -ENOMEM;
  }

  static void nvm_unregister_map(struct nvm_dev *dev)
  {
  	struct nvm_dev_map *rmap = dev->rmap;
  	int i;

  	for (i = 0; i < dev->geo.num_ch; i++)

  		kfree(rmap->chnls[i].lun_offs);
  
  	kfree(rmap->chnls);
  	kfree(rmap);
  }

  static void nvm_map_to_dev(struct nvm_tgt_dev *tgt_dev, struct ppa_addr *p)

  {
  	struct nvm_dev_map *dev_map = tgt_dev->map;

  	struct nvm_ch_map *ch_map = &dev_map->chnls[p->a.ch];
  	int lun_off = ch_map->lun_offs[p->a.lun];

  	p->a.ch += ch_map->ch_off;
  	p->a.lun += lun_off;

  }

  static void nvm_map_to_tgt(struct nvm_tgt_dev *tgt_dev, struct ppa_addr *p)

  {
  	struct nvm_dev *dev = tgt_dev->parent;
  	struct nvm_dev_map *dev_rmap = dev->rmap;

  	struct nvm_ch_map *ch_rmap = &dev_rmap->chnls[p->a.ch];
  	int lun_roff = ch_rmap->lun_offs[p->a.lun];

  	p->a.ch -= ch_rmap->ch_off;
  	p->a.lun -= lun_roff;

  }

  static void nvm_ppa_tgt_to_dev(struct nvm_tgt_dev *tgt_dev,
  				struct ppa_addr *ppa_list, int nr_ppas)

  {
  	int i;

  	for (i = 0; i < nr_ppas; i++) {
  		nvm_map_to_dev(tgt_dev, &ppa_list[i]);

  		ppa_list[i] = generic_to_dev_addr(tgt_dev->parent, ppa_list[i]);

  	}

  }

  static void nvm_ppa_dev_to_tgt(struct nvm_tgt_dev *tgt_dev,
  				struct ppa_addr *ppa_list, int nr_ppas)
  {
  	int i;
  
  	for (i = 0; i < nr_ppas; i++) {

  		ppa_list[i] = dev_to_generic_addr(tgt_dev->parent, ppa_list[i]);

  		nvm_map_to_tgt(tgt_dev, &ppa_list[i]);

  	}

  }

  static void nvm_rq_tgt_to_dev(struct nvm_tgt_dev *tgt_dev, struct nvm_rq *rqd)

  {

  	struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);

  	nvm_ppa_tgt_to_dev(tgt_dev, ppa_list, rqd->nr_ppas);

  }
  
  static void nvm_rq_dev_to_tgt(struct nvm_tgt_dev *tgt_dev, struct nvm_rq *rqd)
  {

  	struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);

  	nvm_ppa_dev_to_tgt(tgt_dev, ppa_list, rqd->nr_ppas);

  }

  int nvm_register_tgt_type(struct nvm_tgt_type *tt)

  {
  	int ret = 0;

  	down_write(&nvm_tgtt_lock);

  	if (__nvm_find_target_type(tt->name))

  		ret = -EEXIST;
  	else

  		list_add(&tt->list, &nvm_tgt_types);

  	up_write(&nvm_tgtt_lock);

  
  	return ret;
  }

  EXPORT_SYMBOL(nvm_register_tgt_type);

  void nvm_unregister_tgt_type(struct nvm_tgt_type *tt)

  {
  	if (!tt)
  		return;

  	down_write(&nvm_tgtt_lock);

  	list_del(&tt->list);

  	up_write(&nvm_tgtt_lock);

  }

  EXPORT_SYMBOL(nvm_unregister_tgt_type);

  
  void *nvm_dev_dma_alloc(struct nvm_dev *dev, gfp_t mem_flags,
  							dma_addr_t *dma_handler)
  {

  	return dev->ops->dev_dma_alloc(dev, dev->dma_pool, mem_flags,

  								dma_handler);
  }
  EXPORT_SYMBOL(nvm_dev_dma_alloc);

  void nvm_dev_dma_free(struct nvm_dev *dev, void *addr, dma_addr_t dma_handler)

  {

  	dev->ops->dev_dma_free(dev->dma_pool, addr, dma_handler);

  }
  EXPORT_SYMBOL(nvm_dev_dma_free);

  static struct nvm_dev *nvm_find_nvm_dev(const char *name)
  {
  	struct nvm_dev *dev;
  
  	list_for_each_entry(dev, &nvm_devices, devices)
  		if (!strcmp(name, dev->name))
  			return dev;
  
  	return NULL;
  }

  static int nvm_set_rqd_ppalist(struct nvm_tgt_dev *tgt_dev, struct nvm_rq *rqd,
  			const struct ppa_addr *ppas, int nr_ppas)
  {
  	struct nvm_dev *dev = tgt_dev->parent;
  	struct nvm_geo *geo = &tgt_dev->geo;
  	int i, plane_cnt, pl_idx;
  	struct ppa_addr ppa;

  	if (geo->pln_mode == NVM_PLANE_SINGLE && nr_ppas == 1) {

  		rqd->nr_ppas = nr_ppas;
  		rqd->ppa_addr = ppas[0];
  
  		return 0;
  	}
  
  	rqd->nr_ppas = nr_ppas;
  	rqd->ppa_list = nvm_dev_dma_alloc(dev, GFP_KERNEL, &rqd->dma_ppa_list);
  	if (!rqd->ppa_list) {

  		pr_err("failed to allocate dma memory
  ");

  		return -ENOMEM;
  	}

  	plane_cnt = geo->pln_mode;

  	rqd->nr_ppas *= plane_cnt;
  
  	for (i = 0; i < nr_ppas; i++) {
  		for (pl_idx = 0; pl_idx < plane_cnt; pl_idx++) {
  			ppa = ppas[i];
  			ppa.g.pl = pl_idx;
  			rqd->ppa_list[(pl_idx * nr_ppas) + i] = ppa;
  		}
  	}
  
  	return 0;
  }
  
  static void nvm_free_rqd_ppalist(struct nvm_tgt_dev *tgt_dev,
  			struct nvm_rq *rqd)
  {
  	if (!rqd->ppa_list)
  		return;
  
  	nvm_dev_dma_free(tgt_dev->parent, rqd->ppa_list, rqd->dma_ppa_list);
  }

  static int nvm_set_flags(struct nvm_geo *geo, struct nvm_rq *rqd)
  {
  	int flags = 0;
  
  	if (geo->version == NVM_OCSSD_SPEC_20)
  		return 0;
  
  	if (rqd->is_seq)
  		flags |= geo->pln_mode >> 1;
  
  	if (rqd->opcode == NVM_OP_PREAD)
  		flags |= (NVM_IO_SCRAMBLE_ENABLE | NVM_IO_SUSPEND);
  	else if (rqd->opcode == NVM_OP_PWRITE)
  		flags |= NVM_IO_SCRAMBLE_ENABLE;
  
  	return flags;
  }

  int nvm_submit_io(struct nvm_tgt_dev *tgt_dev, struct nvm_rq *rqd, void *buf)

  {

  	struct nvm_dev *dev = tgt_dev->parent;

  	int ret;

  	if (!dev->ops->submit_io)
  		return -ENODEV;

  	nvm_rq_tgt_to_dev(tgt_dev, rqd);

  
  	rqd->dev = tgt_dev;

  	rqd->flags = nvm_set_flags(&tgt_dev->geo, rqd);

  
  	/* In case of error, fail with right address format */

  	ret = dev->ops->submit_io(dev, rqd, buf);

  	if (ret)
  		nvm_rq_dev_to_tgt(tgt_dev, rqd);
  	return ret;

  }
  EXPORT_SYMBOL(nvm_submit_io);

  static void nvm_sync_end_io(struct nvm_rq *rqd)
  {
  	struct completion *waiting = rqd->private;
  
  	complete(waiting);
  }

  static int nvm_submit_io_wait(struct nvm_dev *dev, struct nvm_rq *rqd,
  			      void *buf)

  {
  	DECLARE_COMPLETION_ONSTACK(wait);
  	int ret = 0;
  
  	rqd->end_io = nvm_sync_end_io;
  	rqd->private = &wait;

  	ret = dev->ops->submit_io(dev, rqd, buf);

  	if (ret)
  		return ret;
  
  	wait_for_completion_io(&wait);
  
  	return 0;
  }

  int nvm_submit_io_sync(struct nvm_tgt_dev *tgt_dev, struct nvm_rq *rqd,
  		       void *buf)

  {

  	struct nvm_dev *dev = tgt_dev->parent;
  	int ret;

  	if (!dev->ops->submit_io)

  		return -ENODEV;
  
  	nvm_rq_tgt_to_dev(tgt_dev, rqd);

  	rqd->dev = tgt_dev;

  	rqd->flags = nvm_set_flags(&tgt_dev->geo, rqd);

  	ret = nvm_submit_io_wait(dev, rqd, buf);

  
  	return ret;

  }

  EXPORT_SYMBOL(nvm_submit_io_sync);

  void nvm_end_io(struct nvm_rq *rqd)

  {

  	struct nvm_tgt_dev *tgt_dev = rqd->dev;

  
  	/* Convert address space */
  	if (tgt_dev)

  		nvm_rq_dev_to_tgt(tgt_dev, rqd);

  	if (rqd->end_io)
  		rqd->end_io(rqd);

  }
  EXPORT_SYMBOL(nvm_end_io);

  static int nvm_submit_io_sync_raw(struct nvm_dev *dev, struct nvm_rq *rqd)
  {

  	if (!dev->ops->submit_io)

  		return -ENODEV;

  	rqd->dev = NULL;

  	rqd->flags = nvm_set_flags(&dev->geo, rqd);

  	return nvm_submit_io_wait(dev, rqd, NULL);

  }
  
  static int nvm_bb_chunk_sense(struct nvm_dev *dev, struct ppa_addr ppa)
  {
  	struct nvm_rq rqd = { NULL };
  	struct bio bio;
  	struct bio_vec bio_vec;
  	struct page *page;
  	int ret;
  
  	page = alloc_page(GFP_KERNEL);
  	if (!page)
  		return -ENOMEM;
  
  	bio_init(&bio, &bio_vec, 1);
  	bio_add_page(&bio, page, PAGE_SIZE, 0);
  	bio_set_op_attrs(&bio, REQ_OP_READ, 0);
  
  	rqd.bio = &bio;
  	rqd.opcode = NVM_OP_PREAD;
  	rqd.is_seq = 1;
  	rqd.nr_ppas = 1;
  	rqd.ppa_addr = generic_to_dev_addr(dev, ppa);
  
  	ret = nvm_submit_io_sync_raw(dev, &rqd);
  	if (ret)
  		return ret;
  
  	__free_page(page);
  
  	return rqd.error;
  }

  /*

   * Scans a 1.2 chunk first and last page to determine if its state.
   * If the chunk is found to be open, also scan it to update the write
   * pointer.

   */

  static int nvm_bb_chunk_scan(struct nvm_dev *dev, struct ppa_addr ppa,
  			     struct nvm_chk_meta *meta)

  {

  	struct nvm_geo *geo = &dev->geo;

  	int ret, pg, pl;

  	/* sense first page */
  	ret = nvm_bb_chunk_sense(dev, ppa);
  	if (ret < 0) /* io error */
  		return ret;
  	else if (ret == 0) /* valid data */
  		meta->state = NVM_CHK_ST_OPEN;
  	else if (ret > 0) {
  		/*
  		 * If empty page, the chunk is free, else it is an
  		 * actual io error. In that case, mark it offline.
  		 */
  		switch (ret) {
  		case NVM_RSP_ERR_EMPTYPAGE:
  			meta->state = NVM_CHK_ST_FREE;
  			return 0;
  		case NVM_RSP_ERR_FAILCRC:
  		case NVM_RSP_ERR_FAILECC:
  		case NVM_RSP_WARN_HIGHECC:
  			meta->state = NVM_CHK_ST_OPEN;
  			goto scan;
  		default:
  			return -ret; /* other io error */
  		}
  	}
  
  	/* sense last page */
  	ppa.g.pg = geo->num_pg - 1;
  	ppa.g.pl = geo->num_pln - 1;
  
  	ret = nvm_bb_chunk_sense(dev, ppa);
  	if (ret < 0) /* io error */
  		return ret;
  	else if (ret == 0) { /* Chunk fully written */
  		meta->state = NVM_CHK_ST_CLOSED;
  		meta->wp = geo->clba;
  		return 0;
  	} else if (ret > 0) {
  		switch (ret) {
  		case NVM_RSP_ERR_EMPTYPAGE:
  		case NVM_RSP_ERR_FAILCRC:
  		case NVM_RSP_ERR_FAILECC:
  		case NVM_RSP_WARN_HIGHECC:
  			meta->state = NVM_CHK_ST_OPEN;
  			break;
  		default:
  			return -ret; /* other io error */
  		}
  	}
  
  scan:
  	/*
  	 * chunk is open, we scan sequentially to update the write pointer.
  	 * We make the assumption that targets write data across all planes
  	 * before moving to the next page.
  	 */
  	for (pg = 0; pg < geo->num_pg; pg++) {
  		for (pl = 0; pl < geo->num_pln; pl++) {
  			ppa.g.pg = pg;
  			ppa.g.pl = pl;
  
  			ret = nvm_bb_chunk_sense(dev, ppa);
  			if (ret < 0) /* io error */
  				return ret;
  			else if (ret == 0) {
  				meta->wp += geo->ws_min;
  			} else if (ret > 0) {
  				switch (ret) {
  				case NVM_RSP_ERR_EMPTYPAGE:
  					return 0;
  				case NVM_RSP_ERR_FAILCRC:
  				case NVM_RSP_ERR_FAILECC:
  				case NVM_RSP_WARN_HIGHECC:
  					meta->wp += geo->ws_min;
  					break;
  				default:
  					return -ret; /* other io error */
  				}
  			}
  		}
  	}
  
  	return 0;
  }
  
  /*
   * folds a bad block list from its plane representation to its
   * chunk representation.
   *
   * If any of the planes status are bad or grown bad, the chunk is marked
   * offline. If not bad, the first plane state acts as the chunk state.
   */
  static int nvm_bb_to_chunk(struct nvm_dev *dev, struct ppa_addr ppa,
  			   u8 *blks, int nr_blks, struct nvm_chk_meta *meta)
  {
  	struct nvm_geo *geo = &dev->geo;
  	int ret, blk, pl, offset, blktype;

  	for (blk = 0; blk < geo->num_chk; blk++) {
  		offset = blk * geo->pln_mode;

  		blktype = blks[offset];

  		for (pl = 0; pl < geo->pln_mode; pl++) {

  			if (blks[offset + pl] &
  					(NVM_BLK_T_BAD|NVM_BLK_T_GRWN_BAD)) {
  				blktype = blks[offset + pl];
  				break;
  			}
  		}

  		ppa.g.blk = blk;
  
  		meta->wp = 0;
  		meta->type = NVM_CHK_TP_W_SEQ;
  		meta->wi = 0;
  		meta->slba = generic_to_dev_addr(dev, ppa).ppa;
  		meta->cnlb = dev->geo.clba;
  
  		if (blktype == NVM_BLK_T_FREE) {
  			ret = nvm_bb_chunk_scan(dev, ppa, meta);
  			if (ret)
  				return ret;
  		} else {
  			meta->state = NVM_CHK_ST_OFFLINE;
  		}
  
  		meta++;

  	}

  	return 0;

  }

  static int nvm_get_bb_meta(struct nvm_dev *dev, sector_t slba,
  			   int nchks, struct nvm_chk_meta *meta)
  {
  	struct nvm_geo *geo = &dev->geo;
  	struct ppa_addr ppa;
  	u8 *blks;
  	int ch, lun, nr_blks;

  	int ret = 0;

  
  	ppa.ppa = slba;
  	ppa = dev_to_generic_addr(dev, ppa);
  
  	if (ppa.g.blk != 0)
  		return -EINVAL;
  
  	if ((nchks % geo->num_chk) != 0)
  		return -EINVAL;
  
  	nr_blks = geo->num_chk * geo->pln_mode;
  
  	blks = kmalloc(nr_blks, GFP_KERNEL);
  	if (!blks)
  		return -ENOMEM;
  
  	for (ch = ppa.g.ch; ch < geo->num_ch; ch++) {
  		for (lun = ppa.g.lun; lun < geo->num_lun; lun++) {
  			struct ppa_addr ppa_gen, ppa_dev;
  
  			if (!nchks)
  				goto done;
  
  			ppa_gen.ppa = 0;
  			ppa_gen.g.ch = ch;
  			ppa_gen.g.lun = lun;
  			ppa_dev = generic_to_dev_addr(dev, ppa_gen);
  
  			ret = dev->ops->get_bb_tbl(dev, ppa_dev, blks);
  			if (ret)
  				goto done;
  
  			ret = nvm_bb_to_chunk(dev, ppa_gen, blks, nr_blks,
  									meta);
  			if (ret)
  				goto done;
  
  			meta += geo->num_chk;
  			nchks -= geo->num_chk;
  		}
  	}
  done:
  	kfree(blks);
  	return ret;
  }
  
  int nvm_get_chunk_meta(struct nvm_tgt_dev *tgt_dev, struct ppa_addr ppa,
  		       int nchks, struct nvm_chk_meta *meta)

  {

  	struct nvm_dev *dev = tgt_dev->parent;

  	nvm_ppa_tgt_to_dev(tgt_dev, &ppa, 1);

  	if (dev->geo.version == NVM_OCSSD_SPEC_12)
  		return nvm_get_bb_meta(dev, (sector_t)ppa.ppa, nchks, meta);
  
  	return dev->ops->get_chk_meta(dev, (sector_t)ppa.ppa, nchks, meta);
  }
  EXPORT_SYMBOL_GPL(nvm_get_chunk_meta);
  
  int nvm_set_chunk_meta(struct nvm_tgt_dev *tgt_dev, struct ppa_addr *ppas,
  		       int nr_ppas, int type)
  {
  	struct nvm_dev *dev = tgt_dev->parent;
  	struct nvm_rq rqd;
  	int ret;
  
  	if (dev->geo.version == NVM_OCSSD_SPEC_20)
  		return 0;
  
  	if (nr_ppas > NVM_MAX_VLBA) {

  		pr_err("unable to update all blocks atomically
  ");

  		return -EINVAL;
  	}
  
  	memset(&rqd, 0, sizeof(struct nvm_rq));
  
  	nvm_set_rqd_ppalist(tgt_dev, &rqd, ppas, nr_ppas);
  	nvm_rq_tgt_to_dev(tgt_dev, &rqd);
  
  	ret = dev->ops->set_bb_tbl(dev, &rqd.ppa_addr, rqd.nr_ppas, type);
  	nvm_free_rqd_ppalist(tgt_dev, &rqd);
  	if (ret)
  		return -EINVAL;
  
  	return 0;

  }

  EXPORT_SYMBOL_GPL(nvm_set_chunk_meta);

  static int nvm_core_init(struct nvm_dev *dev)
  {

  	struct nvm_geo *geo = &dev->geo;

  	int ret;

  	dev->lun_map = kcalloc(BITS_TO_LONGS(geo->all_luns),

  					sizeof(unsigned long), GFP_KERNEL);
  	if (!dev->lun_map)
  		return -ENOMEM;

  	INIT_LIST_HEAD(&dev->area_list);
  	INIT_LIST_HEAD(&dev->targets);

  	mutex_init(&dev->mlock);

  	spin_lock_init(&dev->lock);

  	ret = nvm_register_map(dev);
  	if (ret)
  		goto err_fmtype;

  	return 0;

  err_fmtype:
  	kfree(dev->lun_map);
  	return ret;

  }

  static void nvm_free(struct kref *ref)

  {

  	struct nvm_dev *dev = container_of(ref, struct nvm_dev, ref);

  	if (dev->dma_pool)
  		dev->ops->destroy_dma_pool(dev->dma_pool);

  	if (dev->rmap)
  		nvm_unregister_map(dev);

  	kfree(dev->lun_map);

  	kfree(dev);

  }
  
  static int nvm_init(struct nvm_dev *dev)
  {

  	struct nvm_geo *geo = &dev->geo;

  	int ret = -EINVAL;

  	if (dev->ops->identity(dev)) {

  		pr_err("device could not be identified
  ");

  		goto err;
  	}

  	pr_debug("ver:%u.%u nvm_vendor:%x
  ", geo->major_ver_id,
  			geo->minor_ver_id, geo->vmnt);

  	ret = nvm_core_init(dev);
  	if (ret) {

  		pr_err("could not initialize core structures.
  ");

  		goto err;
  	}

  	pr_info("registered %s [%u/%u/%u/%u/%u]
  ",

  			dev->name, dev->geo.ws_min, dev->geo.ws_opt,
  			dev->geo.num_chk, dev->geo.all_luns,
  			dev->geo.num_ch);

  	return 0;
  err:

  	pr_err("failed to initialize nvm
  ");

  	return ret;
  }

  struct nvm_dev *nvm_alloc_dev(int node)

  {

  	struct nvm_dev *dev;
  
  	dev = kzalloc_node(sizeof(struct nvm_dev), GFP_KERNEL, node);
  	if (dev)
  		kref_init(&dev->ref);
  
  	return dev;

  }

  EXPORT_SYMBOL(nvm_alloc_dev);

  int nvm_register(struct nvm_dev *dev)

  {

  	int ret, exp_pool_size;

  	if (!dev->q || !dev->ops) {
  		kref_put(&dev->ref, nvm_free);

  		return -EINVAL;

  	}

  	ret = nvm_init(dev);

  	if (ret) {
  		kref_put(&dev->ref, nvm_free);

  		return ret;

  	}

  	exp_pool_size = max_t(int, PAGE_SIZE,
  			      (NVM_MAX_VLBA * (sizeof(u64) + dev->geo.sos)));
  	exp_pool_size = round_up(exp_pool_size, PAGE_SIZE);
  
  	dev->dma_pool = dev->ops->create_dma_pool(dev, "ppalist",
  						  exp_pool_size);

  	if (!dev->dma_pool) {

  		pr_err("could not create dma pool
  ");

  		kref_put(&dev->ref, nvm_free);

  		return -ENOMEM;

  	}

  	/* register device with a supported media manager */

  	down_write(&nvm_lock);
  	list_add(&dev->devices, &nvm_devices);
  	up_write(&nvm_lock);

  	return 0;

  }
  EXPORT_SYMBOL(nvm_register);

  void nvm_unregister(struct nvm_dev *dev)

  {

  	struct nvm_target *t, *tmp;
  
  	mutex_lock(&dev->mlock);
  	list_for_each_entry_safe(t, tmp, &dev->targets, list) {
  		if (t->dev->parent != dev)
  			continue;

  		__nvm_remove_target(t, false);

  		kref_put(&dev->ref, nvm_free);

  	}
  	mutex_unlock(&dev->mlock);

  	down_write(&nvm_lock);

  	list_del(&dev->devices);
  	up_write(&nvm_lock);

  	kref_put(&dev->ref, nvm_free);

  }
  EXPORT_SYMBOL(nvm_unregister);

  static int __nvm_configure_create(struct nvm_ioctl_create *create)
  {
  	struct nvm_dev *dev;

  	int ret;

  	down_write(&nvm_lock);

  	dev = nvm_find_nvm_dev(create->dev);

  	up_write(&nvm_lock);

  	if (!dev) {

  		pr_err("device not found
  ");

  		return -EINVAL;
  	}

  	kref_get(&dev->ref);
  	ret = nvm_create_tgt(dev, create);
  	if (ret)
  		kref_put(&dev->ref, nvm_free);
  
  	return ret;

  }

  static long nvm_ioctl_info(struct file *file, void __user *arg)
  {
  	struct nvm_ioctl_info *info;
  	struct nvm_tgt_type *tt;
  	int tgt_iter = 0;

  	info = memdup_user(arg, sizeof(struct nvm_ioctl_info));
  	if (IS_ERR(info))
  		return -EFAULT;
  
  	info->version[0] = NVM_VERSION_MAJOR;
  	info->version[1] = NVM_VERSION_MINOR;
  	info->version[2] = NVM_VERSION_PATCH;

  	down_write(&nvm_tgtt_lock);

  	list_for_each_entry(tt, &nvm_tgt_types, list) {

  		struct nvm_ioctl_info_tgt *tgt = &info->tgts[tgt_iter];
  
  		tgt->version[0] = tt->version[0];
  		tgt->version[1] = tt->version[1];
  		tgt->version[2] = tt->version[2];
  		strncpy(tgt->tgtname, tt->name, NVM_TTYPE_NAME_MAX);
  
  		tgt_iter++;
  	}
  
  	info->tgtsize = tgt_iter;

  	up_write(&nvm_tgtt_lock);

  	if (copy_to_user(arg, info, sizeof(struct nvm_ioctl_info))) {
  		kfree(info);

  		return -EFAULT;

  	}

  
  	kfree(info);
  	return 0;
  }
  
  static long nvm_ioctl_get_devices(struct file *file, void __user *arg)
  {
  	struct nvm_ioctl_get_devices *devices;
  	struct nvm_dev *dev;
  	int i = 0;

  	devices = kzalloc(sizeof(struct nvm_ioctl_get_devices), GFP_KERNEL);
  	if (!devices)
  		return -ENOMEM;
  
  	down_write(&nvm_lock);
  	list_for_each_entry(dev, &nvm_devices, devices) {
  		struct nvm_ioctl_device_info *info = &devices->info[i];

  		strlcpy(info->devname, dev->name, sizeof(info->devname));

  		/* kept for compatibility */
  		info->bmversion[0] = 1;
  		info->bmversion[1] = 0;
  		info->bmversion[2] = 0;

  		strlcpy(info->bmname, "gennvm", sizeof(info->bmname));

  		i++;

  		if (i >= ARRAY_SIZE(devices->info)) {
  			pr_err("max %zd devices can be reported.
  ",
  			       ARRAY_SIZE(devices->info));

  			break;
  		}
  	}
  	up_write(&nvm_lock);
  
  	devices->nr_devices = i;

  	if (copy_to_user(arg, devices,
  			 sizeof(struct nvm_ioctl_get_devices))) {
  		kfree(devices);

  		return -EFAULT;

  	}

  
  	kfree(devices);
  	return 0;
  }
  
  static long nvm_ioctl_dev_create(struct file *file, void __user *arg)
  {
  	struct nvm_ioctl_create create;

  	if (copy_from_user(&create, arg, sizeof(struct nvm_ioctl_create)))
  		return -EFAULT;

  	if (create.conf.type == NVM_CONFIG_TYPE_EXTENDED &&
  	    create.conf.e.rsv != 0) {

  		pr_err("reserved config field in use
  ");

  		return -EINVAL;
  	}

  	create.dev[DISK_NAME_LEN - 1] = '\0';
  	create.tgttype[NVM_TTYPE_NAME_MAX - 1] = '\0';
  	create.tgtname[DISK_NAME_LEN - 1] = '\0';
  
  	if (create.flags != 0) {

  		__u32 flags = create.flags;
  
  		/* Check for valid flags */
  		if (flags & NVM_TARGET_FACTORY)
  			flags &= ~NVM_TARGET_FACTORY;
  
  		if (flags) {

  			pr_err("flag not supported
  ");

  			return -EINVAL;
  		}

  	}
  
  	return __nvm_configure_create(&create);
  }
  
  static long nvm_ioctl_dev_remove(struct file *file, void __user *arg)
  {
  	struct nvm_ioctl_remove remove;

  	if (copy_from_user(&remove, arg, sizeof(struct nvm_ioctl_remove)))
  		return -EFAULT;
  
  	remove.tgtname[DISK_NAME_LEN - 1] = '\0';
  
  	if (remove.flags != 0) {

  		pr_err("no flags supported
  ");

  		return -EINVAL;
  	}

  	return nvm_remove_tgt(&remove);

  }

  /* kept for compatibility reasons */

  static long nvm_ioctl_dev_init(struct file *file, void __user *arg)
  {
  	struct nvm_ioctl_dev_init init;

  	if (copy_from_user(&init, arg, sizeof(struct nvm_ioctl_dev_init)))
  		return -EFAULT;
  
  	if (init.flags != 0) {

  		pr_err("no flags supported
  ");

  		return -EINVAL;
  	}

  	return 0;

  }

  /* Kept for compatibility reasons */

  static long nvm_ioctl_dev_factory(struct file *file, void __user *arg)
  {
  	struct nvm_ioctl_dev_factory fact;

  	if (copy_from_user(&fact, arg, sizeof(struct nvm_ioctl_dev_factory)))
  		return -EFAULT;
  
  	fact.dev[DISK_NAME_LEN - 1] = '\0';
  
  	if (fact.flags & ~(NVM_FACTORY_NR_BITS - 1))
  		return -EINVAL;

  	return 0;

  }

  static long nvm_ctl_ioctl(struct file *file, uint cmd, unsigned long arg)
  {
  	void __user *argp = (void __user *)arg;

  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;

  	switch (cmd) {
  	case NVM_INFO:
  		return nvm_ioctl_info(file, argp);
  	case NVM_GET_DEVICES:
  		return nvm_ioctl_get_devices(file, argp);
  	case NVM_DEV_CREATE:
  		return nvm_ioctl_dev_create(file, argp);
  	case NVM_DEV_REMOVE:
  		return nvm_ioctl_dev_remove(file, argp);

  	case NVM_DEV_INIT:
  		return nvm_ioctl_dev_init(file, argp);

  	case NVM_DEV_FACTORY:
  		return nvm_ioctl_dev_factory(file, argp);

  	}
  	return 0;
  }
  
  static const struct file_operations _ctl_fops = {
  	.open = nonseekable_open,
  	.unlocked_ioctl = nvm_ctl_ioctl,
  	.owner = THIS_MODULE,
  	.llseek  = noop_llseek,
  };
  
  static struct miscdevice _nvm_misc = {
  	.minor		= MISC_DYNAMIC_MINOR,
  	.name		= "lightnvm",
  	.nodename	= "lightnvm/control",
  	.fops		= &_ctl_fops,
  };

  builtin_misc_device(_nvm_misc);