path: root/drivers/lightnvm/core.c

/*
 * Copyright (C) 2015 IT University of Copenhagen. All rights reserved.
 * Initial release: Matias Bjorling <m@bjorling.me>
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
 * USA.
 *
 */

#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 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("nvm: lun %d already allocated\n", 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(