These changes are the raw update to linux-4.4.6-rt14. Kernel sources

are taken from kernel.org, and rt patch from the rt wiki download page.

During the rebasing, the following patch collided:

Force tick interrupt and get rid of softirq magic(I70131fb85).

Collisions have been removed because its logic was found on the
source already.

Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>

7 files changed, 3076 insertions, 0 deletions

diff --git a/kernel/drivers/lightnvm/Kconfig b/kernel/drivers/lightnvm/Kconfig
new file mode 100644
index 000000000..85a339030
--- /dev/null
+++ b/kernel/drivers/lightnvm/Kconfig
@@ -0,0 +1,43 @@
+#
+# Open-Channel SSD NVM configuration
+#
+
+menuconfig NVM
+	bool "Open-Channel SSD target support"
+	depends on BLOCK
+	help
+	  Say Y here to get to enable Open-channel SSDs.
+
+	  Open-Channel SSDs implement a set of extension to SSDs, that
+	  exposes direct access to the underlying non-volatile memory.
+
+	  If you say N, all options in this submenu will be skipped and disabled
+	  only do this if you know what you are doing.
+
+if NVM
+
+config NVM_DEBUG
+	bool "Open-Channel SSD debugging support"
+	default n
+	---help---
+	Exposes a debug management interface to create/remove targets at:
+
+	  /sys/module/lnvm/parameters/configure_debug
+
+	It is required to create/remove targets without IOCTLs.
+
+config NVM_GENNVM
+	tristate "Generic NVM manager for Open-Channel SSDs"
+	---help---
+	NVM media manager for Open-Channel SSDs that offload management
+	functionality to device, while keeping data placement and garbage
+	collection decisions on the host.
+
+config NVM_RRPC
+	tristate "Round-robin Hybrid Open-Channel SSD target"
+	---help---
+	Allows an open-channel SSD to be exposed as a block device to the
+	host. The target is implemented using a linear mapping table and
+	cost-based garbage collection. It is optimized for 4K IO sizes.
+
+endif # NVM
diff --git a/kernel/drivers/lightnvm/Makefile b/kernel/drivers/lightnvm/Makefile
new file mode 100644
index 000000000..7e0f42acb
--- /dev/null
+++ b/kernel/drivers/lightnvm/Makefile
@@ -0,0 +1,7 @@
+#
+# Makefile for Open-Channel SSDs.
+#
+
+obj-$(CONFIG_NVM)		:= core.o
+obj-$(CONFIG_NVM_GENNVM) 	+= gennvm.o
+obj-$(CONFIG_NVM_RRPC)		+= rrpc.o
diff --git a/kernel/drivers/lightnvm/core.c b/kernel/drivers/lightnvm/core.c
new file mode 100644
index 000000000..8f41b245c
--- /dev/null
+++ b/kernel/drivers/lightnvm/core.c
@@ -0,0 +1,844 @@
+/*
+ * 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/blkdev.h>
+#include <linux/blk-mq.h>
+#include <linux/list.h>
+#include <linux/types.h>
+#include <linux/sem.h>
+#include <linux/bitmap.h>
+#include <linux/module.h>
+#include <linux/miscdevice.h>
+#include <linux/lightnvm.h>
+#include <uapi/linux/lightnvm.h>
+
+static LIST_HEAD(nvm_targets);
+static LIST_HEAD(nvm_mgrs);
+static LIST_HEAD(nvm_devices);
+static DECLARE_RWSEM(nvm_lock);
+
+static struct nvm_tgt_type *nvm_find_target_type(const char *name)
+{
+	struct nvm_tgt_type *tt;
+
+	list_for_each_entry(tt, &nvm_targets, list)
+		if (!strcmp(name, tt->name))
+			return tt;
+
+	return NULL;
+}
+
+int nvm_register_target(struct nvm_tgt_type *tt)
+{
+	int ret = 0;
+
+	down_write(&nvm_lock);
+	if (nvm_find_target_type(tt->name))
+		ret = -EEXIST;
+	else
+		list_add(&tt->list, &nvm_targets);
+	up_write(&nvm_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(nvm_register_target);
+
+void nvm_unregister_target(struct nvm_tgt_type *tt)
+{
+	if (!tt)
+		return;
+
+	down_write(&nvm_lock);
+	list_del(&tt->list);
+	up_write(&nvm_lock);
+}
+EXPORT_SYMBOL(nvm_unregister_target);
+
+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->ppalist_pool, mem_flags,
+								dma_handler);
+}
+EXPORT_SYMBOL(nvm_dev_dma_alloc);
+
+void nvm_dev_dma_free(struct nvm_dev *dev, void *ppa_list,
+							dma_addr_t dma_handler)
+{
+	dev->ops->dev_dma_free(dev->ppalist_pool, ppa_list, dma_handler);
+}
+EXPORT_SYMBOL(nvm_dev_dma_free);
+
+static struct nvmm_type *nvm_find_mgr_type(const char *name)
+{
+	struct nvmm_type *mt;
+
+	list_for_each_entry(mt, &nvm_mgrs, list)
+		if (!strcmp(name, mt->name))
+			return mt;
+
+	return NULL;
+}
+
+struct nvmm_type *nvm_init_mgr(struct nvm_dev *dev)
+{
+	struct nvmm_type *mt;
+	int ret;
+
+	lockdep_assert_held(&nvm_lock);
+
+	list_for_each_entry(mt, &nvm_mgrs, list) {
+		ret = mt->register_mgr(dev);
+		if (ret < 0) {
+			pr_err("nvm: media mgr failed to init (%d) on dev %s\n",
+								ret, dev->name);
+			return NULL; /* initialization failed */
+		} else if (ret > 0)
+			return mt;
+	}
+
+	return NULL;
+}
+
+int nvm_register_mgr(struct nvmm_type *mt)
+{
+	struct nvm_dev *dev;
+	int ret = 0;
+
+	down_write(&nvm_lock);
+	if (nvm_find_mgr_type(mt->name)) {
+		ret = -EEXIST;
+		goto finish;
+	} else {
+		list_add(&mt->list, &nvm_mgrs);
+	}
+
+	/* try to register media mgr if any device have none configured */
+	list_for_each_entry(dev, &nvm_devices, devices) {
+		if (dev->mt)
+			continue;
+
+		dev->mt = nvm_init_mgr(dev);
+	}
+finish:
+	up_write(&nvm_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(nvm_register_mgr);
+
+void nvm_unregister_mgr(struct nvmm_type *mt)
+{
+	if (!mt)
+		return;
+
+	down_write(&nvm_lock);
+	list_del(&mt->list);
+	up_write(&nvm_lock);
+}
+EXPORT_SYMBOL(nvm_unregister_mgr);
+
+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;
+}
+
+struct nvm_block *nvm_get_blk(struct nvm_dev *dev, struct nvm_lun *lun,
+							unsigned long flags)
+{
+	return dev->mt->get_blk(dev, lun, flags);
+}
+EXPORT_SYMBOL(nvm_get_blk);
+
+/* Assumes that all valid pages have already been moved on release to bm */
+void nvm_put_blk(struct nvm_dev *dev, struct nvm_block *blk)
+{
+	return dev->mt->put_blk(dev, blk);
+}
+EXPORT_SYMBOL(nvm_put_blk);
+
+int nvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)
+{
+	return dev->mt->submit_io(dev, rqd);
+}
+EXPORT_SYMBOL(nvm_submit_io);
+
+int nvm_erase_blk(struct nvm_dev *dev, struct nvm_block *blk)
+{
+	return dev->mt->erase_blk(dev, blk, 0);
+}
+EXPORT_SYMBOL(nvm_erase_blk);
+
+static int nvm_core_init(struct nvm_dev *dev)
+{
+	struct nvm_id *id = &dev->identity;
+	struct nvm_id_group *grp = &id->groups[0];
+
+	/* device values */
+	dev->nr_chnls = grp->num_ch;
+	dev->luns_per_chnl = grp->num_lun;
+	dev->pgs_per_blk = grp->num_pg;
+	dev->blks_per_lun = grp->num_blk;
+	dev->nr_planes = grp->num_pln;
+	dev->sec_size = grp->csecs;
+	dev->oob_size = grp->sos;
+	dev->sec_per_pg = grp->fpg_sz / grp->csecs;
+	memcpy(&dev->ppaf, &id->ppaf, sizeof(struct nvm_addr_format));
+
+	dev->plane_mode = NVM_PLANE_SINGLE;
+	dev->max_rq_size = dev->ops->max_phys_sect * dev->sec_size;
+
+	if (grp->mtype != 0) {
+		pr_err("nvm: memory type not supported\n");
+		return -EINVAL;
+	}
+
+	if (grp->fmtype != 0 && grp->fmtype != 1) {
+		pr_err("nvm: flash type not supported\n");
+		return -EINVAL;
+	}
+
+	if (grp->mpos & 0x020202)
+		dev->plane_mode = NVM_PLANE_DOUBLE;
+	if (grp->mpos & 0x040404)
+		dev->plane_mode = NVM_PLANE_QUAD;
+
+	/* calculated values */
+	dev->sec_per_pl = dev->sec_per_pg * dev->nr_planes;
+	dev->sec_per_blk = dev->sec_per_pl * dev->pgs_per_blk;
+	dev->sec_per_lun = dev->sec_per_blk * dev->blks_per_lun;
+	dev->nr_luns = dev->luns_per_chnl * dev->nr_chnls;
+
+	dev->total_blocks = dev->nr_planes *
+				dev->blks_per_lun *
+				dev->luns_per_chnl *
+				dev->nr_chnls;
+	dev->total_pages = dev->total_blocks * dev->pgs_per_blk;
+	INIT_LIST_HEAD(&dev->online_targets);
+
+	return 0;
+}
+
+static void nvm_free(struct nvm_dev *dev)
+{
+	if (!dev)
+		return;
+
+	if (dev->mt)
+		dev->mt->unregister_mgr(dev);
+}
+
+static int nvm_init(struct nvm_dev *dev)
+{
+	int ret = -EINVAL;
+
+	if (!dev->q || !dev->ops)
+		return ret;
+
+	if (dev->ops->identity(dev, &dev->identity)) {
+		pr_err("nvm: device could not be identified\n");
+		goto err;
+	}
+
+	pr_debug("nvm: ver:%x nvm_vendor:%x groups:%u\n",
+			dev->identity.ver_id, dev->identity.vmnt,
+							dev->identity.cgrps);
+
+	if (dev->identity.ver_id != 1) {
+		pr_err("nvm: device not supported by kernel.");
+		goto err;
+	}
+
+	if (dev->identity.cgrps != 1) {
+		pr_err("nvm: only one group configuration supported.");
+		goto err;
+	}
+
+	ret = nvm_core_init(dev);
+	if (ret) {
+		pr_err("nvm: could not initialize core structures.\n");
+		goto err;
+	}
+
+	pr_info("nvm: registered %s [%u/%u/%u/%u/%u/%u]\n",
+			dev->name, dev->sec_per_pg, dev->nr_planes,
+			dev->pgs_per_blk, dev->blks_per_lun, dev->nr_luns,
+			dev->nr_chnls);
+	return 0;
+err:
+	pr_err("nvm: failed to initialize nvm\n");
+	return ret;
+}
+
+static void nvm_exit(struct nvm_dev *dev)
+{
+	if (dev->ppalist_pool)
+		dev->ops->destroy_dma_pool(dev->ppalist_pool);
+	nvm_free(dev);
+
+	pr_info("nvm: successfully unloaded\n");
+}
+
+int nvm_register(struct request_queue *q, char *disk_name,
+							struct nvm_dev_ops *ops)
+{
+	struct nvm_dev *dev;
+	int ret;
+
+	if (!ops->identity)
+		return -EINVAL;
+
+	dev = kzalloc(sizeof(struct nvm_dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	dev->q = q;
+	dev->ops = ops;
+	strncpy(dev->name, disk_name, DISK_NAME_LEN);
+
+	ret = nvm_init(dev);
+	if (ret)
+		goto err_init;
+
+	if (dev->ops->max_phys_sect > 256) {
+		pr_info("nvm: max sectors supported is 256.\n");
+		ret = -EINVAL;
+		goto err_init;
+	}
+
+	if (dev->ops->max_phys_sect > 1) {
+		dev->ppalist_pool = dev->ops->create_dma_pool(dev, "ppalist");
+		if (!dev->ppalist_pool) {
+			pr_err("nvm: could not create ppa pool\n");
+			ret = -ENOMEM;
+			goto err_init;
+		}
+	}
+
+	/* register device with a supported media manager */
+	down_write(&nvm_lock);
+	dev->mt = nvm_init_mgr(dev);
+	list_add(&dev->devices, &nvm_devices);
+	up_write(&nvm_lock);
+
+	return 0;
+err_init:
+	kfree(dev);
+	return ret;
+}
+EXPORT_SYMBOL(nvm_register);
+
+void nvm_unregister(char *disk_name)
+{
+	struct nvm_dev *dev;
+
+	down_write(&nvm_lock);
+	dev = nvm_find_nvm_dev(disk_name);
+	if (!dev) {
+		pr_err("nvm: could not find device %s to unregister\n",
+								disk_name);
+		up_write(&nvm_lock);
+		return;
+	}
+
+	list_del(&dev->devices);
+	up_write(&nvm_lock);
+
+	nvm_exit(dev);
+	kfree(dev);
+}
+EXPORT_SYMBOL(nvm_unregister);
+
+static const struct block_device_operations nvm_fops = {
+	.owner		= THIS_MODULE,
+};
+
+static int nvm_create_target(struct nvm_dev *dev,
+						struct nvm_ioctl_create *create)
+{
+	struct nvm_ioctl_create_simple *s = &create->conf.s;
+	struct request_queue *tqueue;
+	struct gendisk *tdisk;
+	struct nvm_tgt_type *tt;
+	struct nvm_target *t;
+	void *targetdata;
+
+	if (!dev->mt) {
+		pr_info("nvm: device has no media manager registered.\n");
+		return -ENODEV;
+	}
+
+	down_write(&nvm_lock);
+	tt = nvm_find_target_type(create->tgttype);
+	if (!tt) {
+		pr_err("nvm: target type %s not found\n", create->tgttype);
+		up_write(&nvm_lock);
+		return -EINVAL;
+	}
+
+	list_for_each_entry(t, &dev->online_targets, list) {
+		if (!strcmp(create->tgtname, t->disk->disk_name)) {
+			pr_err("nvm: target name already exists.\n");
+			up_write(&nvm_lock);
+			return -EINVAL;
+		}
+	}
+	up_write(&nvm_lock);
+
+	t = kmalloc(sizeof(struct nvm_target), GFP_KERNEL);
+	if (!t)
+		return -ENOMEM;
+
+	tqueue = blk_alloc_queue_node(GFP_KERNEL, dev->q->node);
+	if (!tqueue)
+		goto err_t;
+	blk_queue_make_request(tqueue, tt->make_rq);
+
+	tdisk = alloc_disk(0);
+	if (!tdisk)
+		goto err_queue;
+
+	sprintf(tdisk->disk_name, "%s", create->tgtname);
+	tdisk->flags = GENHD_FL_EXT_DEVT;
+	tdisk->major = 0;
+	tdisk->first_minor = 0;
+	tdisk->fops = &nvm_fops;
+	tdisk->queue = tqueue;
+
+	targetdata = tt->init(dev, tdisk, s->lun_begin, s->lun_end);
+	if (IS_ERR(targetdata))
+		goto err_init;
+
+	tdisk->private_data = targetdata;
+	tqueue->queuedata = targetdata;
+
+	blk_queue_max_hw_sectors(tqueue, 8 * dev->ops->max_phys_sect);
+
+	set_capacity(tdisk, tt->capacity(targetdata));
+	add_disk(tdisk);
+
+	t->type = tt;
+	t->disk = tdisk;
+
+	down_write(&nvm_lock);
+	list_add_tail(&t->list, &dev->online_targets);
+	up_write(&nvm_lock);
+
+	return 0;
+err_init:
+	put_disk(tdisk);
+err_queue:
+	blk_cleanup_queue(tqueue);
+err_t:
+	kfree(t);
+	return -ENOMEM;
+}
+
+static void nvm_remove_target(struct nvm_target *t)
+{
+	struct nvm_tgt_type *tt = t->type;
+	struct gendisk *tdisk = t->disk;
+	struct request_queue *q = tdisk->queue;
+
+	lockdep_assert_held(&nvm_lock);
+
+	del_gendisk(tdisk);
+	blk_cleanup_queue(q);
+
+	if (tt->exit)
+		tt->exit(tdisk->private_data);
+
+	put_disk(tdisk);
+
+	list_del(&t->list);
+	kfree(t);
+}
+
+static int __nvm_configure_create(struct nvm_ioctl_create *create)
+{
+	struct nvm_dev *dev;
+	struct nvm_ioctl_create_simple *s;
+
+	down_write(&nvm_lock);
+	dev = nvm_find_nvm_dev(create->dev);
+	up_write(&nvm_lock);
+	if (!dev) {
+		pr_err("nvm: device not found\n");
+		return -EINVAL;
+	}
+
+	if (create->conf.type != NVM_CONFIG_TYPE_SIMPLE) {
+		pr_err("nvm: config type not valid\n");
+		return -EINVAL;
+	}
+	s = &create->conf.s;
+
+	if (s->lun_begin > s->lun_end || s->lun_end > dev->nr_luns) {
+		pr_err("nvm: lun out of bound (%u:%u > %u)\n",
+			s->lun_begin, s->lun_end, dev->nr_luns);
+		return -EINVAL;
+	}
+
+	return nvm_create_target(dev, create);
+}
+
+static int __nvm_configure_remove(struct nvm_ioctl_remove *remove)
+{
+	struct nvm_target *t = NULL;
+	struct nvm_dev *dev;
+	int ret = -1;
+
+	down_write(&nvm_lock);
+	list_for_each_entry(dev, &nvm_devices, devices)
+		list_for_each_entry(t, &dev->online_targets, list) {
+			if (!strcmp(remove->tgtname, t->disk->disk_name)) {
+				nvm_remove_target(t);
+				ret = 0;
+				break;
+			}
+		}
+	up_write(&nvm_lock);
+
+	if (ret) {
+		pr_err("nvm: target \"%s\" doesn't exist.\n", remove->tgtname);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_NVM_DEBUG
+static int nvm_configure_show(const char *val)
+{
+	struct nvm_dev *dev;
+	char opcode, devname[DISK_NAME_LEN];
+	int ret;
+
+	ret = sscanf(val, "%c %32s", &opcode, devname);
+	if (ret != 2) {
+		pr_err("nvm: invalid command. Use \"opcode devicename\".\n");
+		return -EINVAL;
+	}
+
+	down_write(&nvm_lock);
+	dev = nvm_find_nvm_dev(devname);
+	up_write(&nvm_lock);
+	if (!dev) {
+		pr_err("nvm: device not found\n");
+		return -EINVAL;
+	}
+
+	if (!dev->mt)
+		return 0;
+
+	dev->mt->lun_info_print(dev);
+
+	return 0;
+}
+
+static int nvm_configure_remove(const char *val)
+{
+	struct nvm_ioctl_remove remove;
+	char opcode;
+	int ret;
+
+	ret = sscanf(val, "%c %256s", &opcode, remove.tgtname);
+	if (ret != 2) {
+		pr_err("nvm: invalid command. Use \"d targetname\".\n");
+		return -EINVAL;
+	}
+
+	remove.flags = 0;
+
+	return __nvm_configure_remove(&remove);
+}
+
+static int nvm_configure_create(const char *val)
+{
+	struct nvm_ioctl_create create;
+	char opcode;
+	int lun_begin, lun_end, ret;
+
+	ret = sscanf(val, "%c %256s %256s %48s %u:%u", &opcode, create.dev,
+						create.tgtname, create.tgttype,
+						&lun_begin, &lun_end);
+	if (ret != 6) {
+		pr_err("nvm: invalid command. Use \"opcode device name tgttype lun_begin:lun_end\".\n");
+		return -EINVAL;
+	}
+
+	create.flags = 0;
+	create.conf.type = NVM_CONFIG_TYPE_SIMPLE;
+	create.conf.s.lun_begin = lun_begin;
+	create.conf.s.lun_end = lun_end;
+
+	return __nvm_configure_create(&create);
+}
+
+
+/* Exposes administrative interface through /sys/module/lnvm/configure_by_str */
+static int nvm_configure_by_str_event(const char *val,
+					const struct kernel_param *kp)
+{
+	char opcode;
+	int ret;
+
+	ret = sscanf(val, "%c", &opcode);
+	if (ret != 1) {
+		pr_err("nvm: string must have the format of \"cmd ...\"\n");
+		return -EINVAL;
+	}
+
+	switch (opcode) {
+	case 'a':
+		return nvm_configure_create(val);
+	case 'd':
+		return nvm_configure_remove(val);
+	case 's':
+		return nvm_configure_show(val);
+	default:
+		pr_err("nvm: invalid command\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int nvm_configure_get(char *buf, const struct kernel_param *kp)
+{
+	int sz = 0;
+	char *buf_start = buf;
+	struct nvm_dev *dev;
+
+	buf += sprintf(buf, "available devices:\n");
+	down_write(&nvm_lock);
+	list_for_each_entry(dev, &nvm_devices, devices) {
+		if (sz > 4095 - DISK_NAME_LEN)
+			break;
+		buf += sprintf(buf, " %32s\n", dev->name);
+	}
+	up_write(&nvm_lock);
+
+	return buf - buf_start - 1;
+}
+
+static const struct kernel_param_ops nvm_configure_by_str_event_param_ops = {
+	.set	= nvm_configure_by_str_event,
+	.get	= nvm_configure_get,
+};
+
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX	"lnvm."
+
+module_param_cb(configure_debug, &nvm_configure_by_str_event_param_ops, NULL,
+									0644);
+
+#endif /* CONFIG_NVM_DEBUG */
+
+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;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	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_lock);
+	list_for_each_entry(tt, &nvm_targets, 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_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;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	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];
+
+		sprintf(info->devname, "%s", dev->name);
+		if (dev->mt) {
+			info->bmversion[0] = dev->mt->version[0];
+			info->bmversion[1] = dev->mt->version[1];
+			info->bmversion[2] = dev->mt->version[2];
+			sprintf(info->bmname, "%s", dev->mt->name);
+		} else {
+			sprintf(info->bmname, "none");
+		}
+
+		i++;
+		if (i > 31) {
+			pr_err("nvm: max 31 devices can be reported.\n");
+			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 (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (copy_from_user(&create, arg, sizeof(struct nvm_ioctl_create)))
+		return -EFAULT;
+
+	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) {
+		pr_err("nvm: no flags supported\n");
+		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 (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	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("nvm: no flags supported\n");
+		return -EINVAL;
+	}
+
+	return __nvm_configure_remove(&remove);
+}
+
+static long nvm_ctl_ioctl(struct file *file, uint cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+
+	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);
+	}
+	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,
+};
+
+MODULE_ALIAS_MISCDEV(MISC_DYNAMIC_MINOR);
+
+static int __init nvm_mod_init(void)
+{
+	int ret;
+
+	ret = misc_register(&_nvm_misc);
+	if (ret)
+		pr_err("nvm: misc_register failed for control device");
+
+	return ret;
+}
+
+static void __exit nvm_mod_exit(void)
+{
+	misc_deregister(&_nvm_misc);
+}
+
+MODULE_AUTHOR("Matias Bjorling <m@bjorling.me>");
+MODULE_LICENSE("GPL v2");
+MODULE_VERSION("0.1");
+module_init(nvm_mod_init);
+module_exit(nvm_mod_exit);
diff --git a/kernel/drivers/lightnvm/gennvm.c b/kernel/drivers/lightnvm/gennvm.c
new file mode 100644
index 000000000..a54b33995
--- /dev/null
+++ b/kernel/drivers/lightnvm/gennvm.c
@@ -0,0 +1,524 @@
+/*
+ * Copyright (C) 2015 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.
+ *
+ * Implementation of a generic nvm manager for Open-Channel SSDs.
+ */
+
+#include "gennvm.h"
+
+static void gennvm_blocks_free(struct nvm_dev *dev)
+{
+	struct gen_nvm *gn = dev->mp;
+	struct gen_lun *lun;
+	int i;
+
+	gennvm_for_each_lun(gn, lun, i) {
+		if (!lun->vlun.blocks)
+			break;
+		vfree(lun->vlun.blocks);
+	}
+}
+
+static void gennvm_luns_free(struct nvm_dev *dev)
+{
+	struct gen_nvm *gn = dev->mp;
+
+	kfree(gn->luns);
+}
+
+static int gennvm_luns_init(struct nvm_dev *dev, struct gen_nvm *gn)
+{
+	struct gen_lun *lun;
+	int i;
+
+	gn->luns = kcalloc(dev->nr_luns, sizeof(struct gen_lun), GFP_KERNEL);
+	if (!gn->luns)
+		return -ENOMEM;
+
+	gennvm_for_each_lun(gn, lun, i) {
+		spin_lock_init(&lun->vlun.lock);
+		INIT_LIST_HEAD(&lun->free_list);
+		INIT_LIST_HEAD(&lun->used_list);
+		INIT_LIST_HEAD(&lun->bb_list);
+
+		lun->reserved_blocks = 2; /* for GC only */
+		lun->vlun.id = i;
+		lun->vlun.lun_id = i % dev->luns_per_chnl;
+		lun->vlun.chnl_id = i / dev->luns_per_chnl;
+		lun->vlun.nr_free_blocks = dev->blks_per_lun;
+		lun->vlun.nr_inuse_blocks = 0;
+		lun->vlun.nr_bad_blocks = 0;
+	}
+	return 0;
+}
+
+static int gennvm_block_bb(struct ppa_addr ppa, int nr_blocks, u8 *blks,
+								void *private)
+{
+	struct gen_nvm *gn = private;
+	struct nvm_dev *dev = gn->dev;
+	struct gen_lun *lun;
+	struct nvm_block *blk;
+	int i;
+
+	lun = &gn->luns[(dev->luns_per_chnl * ppa.g.ch) + ppa.g.lun];
+
+	for (i = 0; i < nr_blocks; i++) {
+		if (blks[i] == 0)
+			continue;
+
+		blk = &lun->vlun.blocks[i];
+		if (!blk) {
+			pr_err("gennvm: BB data is out of bounds.\n");
+			return -EINVAL;
+		}
+
+		list_move_tail(&blk->list, &lun->bb_list);
+		lun->vlun.nr_bad_blocks++;
+	}
+
+	return 0;
+}
+
+static int gennvm_block_map(u64 slba, u32 nlb, __le64 *entries, void *private)
+{
+	struct nvm_dev *dev = private;
+	struct gen_nvm *gn = dev->mp;
+	sector_t max_pages = dev->total_pages * (dev->sec_size >> 9);
+	u64 elba = slba + nlb;
+	struct gen_lun *lun;
+	struct nvm_block *blk;
+	u64 i;
+	int lun_id;
+
+	if (unlikely(elba > dev->total_pages)) {
+		pr_err("gennvm: L2P data from device is out of bounds!\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < nlb; i++) {
+		u64 pba = le64_to_cpu(entries[i]);
+
+		if (unlikely(pba >= max_pages && pba != U64_MAX)) {
+			pr_err("gennvm: L2P data entry is out of bounds!\n");
+			return -EINVAL;
+		}
+
+		/* Address zero is a special one. The first page on a disk is
+		 * protected. It often holds internal device boot
+		 * information.
+		 */
+		if (!pba)
+			continue;
+
+		/* resolve block from physical address */
+		lun_id = div_u64(pba, dev->sec_per_lun);
+		lun = &gn->luns[lun_id];
+
+		/* Calculate block offset into lun */
+		pba = pba - (dev->sec_per_lun * lun_id);
+		blk = &lun->vlun.blocks[div_u64(pba, dev->sec_per_blk)];
+
+		if (!blk->type) {
+			/* at this point, we don't know anything about the
+			 * block. It's up to the FTL on top to re-etablish the
+			 * block state
+			 */
+			list_move_tail(&blk->list, &lun->used_list);
+			blk->type = 1;
+			lun->vlun.nr_free_blocks--;
+			lun->vlun.nr_inuse_blocks++;
+		}
+	}
+
+	return 0;
+}
+
+static int gennvm_blocks_init(struct nvm_dev *dev, struct gen_nvm *gn)
+{
+	struct gen_lun *lun;
+	struct nvm_block *block;
+	sector_t lun_iter, blk_iter, cur_block_id = 0;
+	int ret;
+
+	gennvm_for_each_lun(gn, lun, lun_iter) {
+		lun->vlun.blocks = vzalloc(sizeof(struct nvm_block) *
+							dev->blks_per_lun);
+		if (!lun->vlun.blocks)
+			return -ENOMEM;
+
+		for (blk_iter = 0; blk_iter < dev->blks_per_lun; blk_iter++) {
+			block = &lun->vlun.blocks[blk_iter];
+
+			INIT_LIST_HEAD(&block->list);
+
+			block->lun = &lun->vlun;
+			block->id = cur_block_id++;
+
+			/* First block is reserved for device */
+			if (unlikely(lun_iter == 0 && blk_iter == 0)) {
+				lun->vlun.nr_free_blocks--;
+				continue;
+			}
+
+			list_add_tail(&block->list, &lun->free_list);
+		}
+
+		if (dev->ops->get_bb_tbl) {
+			struct ppa_addr ppa;
+
+			ppa.ppa = 0;
+			ppa.g.ch = lun->vlun.chnl_id;
+			ppa.g.lun = lun->vlun.id;
+			ppa = generic_to_dev_addr(dev, ppa);
+
+			ret = dev->ops->get_bb_tbl(dev, ppa,
+						dev->blks_per_lun,
+						gennvm_block_bb, gn);
+			if (ret)
+				pr_err("gennvm: could not read BB table\n");
+		}
+	}
+
+	if (dev->ops->get_l2p_tbl) {
+		ret = dev->ops->get_l2p_tbl(dev, 0, dev->total_pages,
+							gennvm_block_map, dev);
+		if (ret) {
+			pr_err("gennvm: could not read L2P table.\n");
+			pr_warn("gennvm: default block initialization");
+		}
+	}
+
+	return 0;
+}
+
+static void gennvm_free(struct nvm_dev *dev)
+{
+	gennvm_blocks_free(dev);
+	gennvm_luns_free(dev);
+	kfree(dev->mp);
+	dev->mp = NULL;
+}
+
+static int gennvm_register(struct nvm_dev *dev)
+{
+	struct gen_nvm *gn;
+	int ret;
+
+	if (!try_module_get(THIS_MODULE))
+		return -ENODEV;
+
+	gn = kzalloc(sizeof(struct gen_nvm), GFP_KERNEL);
+	if (!gn)
+		return -ENOMEM;
+
+	gn->dev = dev;
+	gn->nr_luns = dev->nr_luns;
+	dev->mp = gn;
+
+	ret = gennvm_luns_init(dev, gn);
+	if (ret) {
+		pr_err("gennvm: could not initialize luns\n");
+		goto err;
+	}
+
+	ret = gennvm_blocks_init(dev, gn);
+	if (ret) {
+		pr_err("gennvm: could not initialize blocks\n");
+		goto err;
+	}
+
+	return 1;
+err:
+	gennvm_free(dev);
+	module_put(THIS_MODULE);
+	return ret;
+}
+
+static void gennvm_unregister(struct nvm_dev *dev)
+{
+	gennvm_free(dev);
+	module_put(THIS_MODULE);
+}
+
+static struct nvm_block *gennvm_get_blk(struct nvm_dev *dev,
+				struct nvm_lun *vlun, unsigned long flags)
+{
+	struct gen_lun *lun = container_of(vlun, struct gen_lun, vlun);
+	struct nvm_block *blk = NULL;
+	int is_gc = flags & NVM_IOTYPE_GC;
+
+	spin_lock(&vlun->lock);
+
+	if (list_empty(&lun->free_list)) {
+		pr_err_ratelimited("gennvm: lun %u have no free pages available",
+								lun->vlun.id);
+		goto out;
+	}
+
+	if (!is_gc && lun->vlun.nr_free_blocks < lun->reserved_blocks)
+		goto out;
+
+	blk = list_first_entry(&lun->free_list, struct nvm_block, list);
+	list_move_tail(&blk->list, &lun->used_list);
+	blk->type = 1;
+
+	lun->vlun.nr_free_blocks--;
+	lun->vlun.nr_inuse_blocks++;
+
+out:
+	spin_unlock(&vlun->lock);
+	return blk;
+}
+
+static void gennvm_put_blk(struct nvm_dev *dev, struct nvm_block *blk)
+{
+	struct nvm_lun *vlun = blk->lun;
+	struct gen_lun *lun = container_of(vlun, struct gen_lun, vlun);
+
+	spin_lock(&vlun->lock);
+
+	switch (blk->type) {
+	case 1:
+		list_move_tail(&blk->list, &lun->free_list);
+		lun->vlun.nr_free_blocks++;
+		lun->vlun.nr_inuse_blocks--;
+		blk->type = 0;
+		break;
+	case 2:
+		list_move_tail(&blk->list, &lun->bb_list);
+		lun->vlun.nr_bad_blocks++;
+		lun->vlun.nr_inuse_blocks--;
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		pr_err("gennvm: erroneous block type (%lu -> %u)\n",
+							blk->id, blk->type);
+		list_move_tail(&blk->list, &lun->bb_list);
+		lun->vlun.nr_bad_blocks++;
+		lun->vlun.nr_inuse_blocks--;
+	}
+
+	spin_unlock(&vlun->lock);
+}
+
+static void gennvm_addr_to_generic_mode(struct nvm_dev *dev, struct nvm_rq *rqd)
+{
+	int i;
+
+	if (rqd->nr_pages > 1) {
+		for (i = 0; i < rqd->nr_pages; i++)
+			rqd->ppa_list[i] = dev_to_generic_addr(dev,
+							rqd->ppa_list[i]);
+	} else {
+		rqd->ppa_addr = dev_to_generic_addr(dev, rqd->ppa_addr);
+	}
+}
+
+static void gennvm_generic_to_addr_mode(struct nvm_dev *dev, struct nvm_rq *rqd)
+{
+	int i;
+
+	if (rqd->nr_pages > 1) {
+		for (i = 0; i < rqd->nr_pages; i++)
+			rqd->ppa_list[i] = generic_to_dev_addr(dev,
+							rqd->ppa_list[i]);
+	} else {
+		rqd->ppa_addr = generic_to_dev_addr(dev, rqd->ppa_addr);
+	}
+}
+
+static int gennvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)
+{
+	if (!dev->ops->submit_io)
+		return 0;
+
+	/* Convert address space */
+	gennvm_generic_to_addr_mode(dev, rqd);
+
+	rqd->dev = dev;
+	return dev->ops->submit_io(dev, rqd);
+}
+
+static void gennvm_blk_set_type(struct nvm_dev *dev, struct ppa_addr *ppa,
+								int type)
+{
+	struct gen_nvm *gn = dev->mp;
+	struct gen_lun *lun;
+	struct nvm_block *blk;
+
+	if (unlikely(ppa->g.ch > dev->nr_chnls ||
+					ppa->g.lun > dev->luns_per_chnl ||
+					ppa->g.blk > dev->blks_per_lun)) {
+		WARN_ON_ONCE(1);
+		pr_err("gennvm: ppa broken (ch: %u > %u lun: %u > %u blk: %u > %u",
+				ppa->g.ch, dev->nr_chnls,
+				ppa->g.lun, dev->luns_per_chnl,
+				ppa->g.blk, dev->blks_per_lun);
+		return;
+	}
+
+	lun = &gn->luns[ppa->g.lun * ppa->g.ch];
+	blk = &lun->vlun.blocks[ppa->g.blk];
+
+	/* will be moved to bb list on put_blk from target */
+	blk->type = type;
+}
+
+/* mark block bad. It is expected the target recover from the error. */
+static void gennvm_mark_blk_bad(struct nvm_dev *dev, struct nvm_rq *rqd)
+{
+	int i;
+
+	if (!dev->ops->set_bb_tbl)
+		return;
+
+	if (dev->ops->set_bb_tbl(dev, rqd, 1))
+		return;
+
+	gennvm_addr_to_generic_mode(dev, rqd);
+
+	/* look up blocks and mark them as bad */
+	if (rqd->nr_pages > 1)
+		for (i = 0; i < rqd->nr_pages; i++)
+			gennvm_blk_set_type(dev, &rqd->ppa_list[i], 2);
+	else
+		gennvm_blk_set_type(dev, &rqd->ppa_addr, 2);
+}
+
+static int gennvm_end_io(struct nvm_rq *rqd, int error)
+{
+	struct nvm_tgt_instance *ins = rqd->ins;
+	int ret = 0;
+
+	switch (error) {
+	case NVM_RSP_SUCCESS:
+		break;
+	case NVM_RSP_ERR_EMPTYPAGE:
+		break;
+	case NVM_RSP_ERR_FAILWRITE:
+		gennvm_mark_blk_bad(rqd->dev, rqd);
+	default:
+		ret++;
+	}
+
+	ret += ins->tt->end_io(rqd, error);
+
+	return ret;
+}
+
+static int gennvm_erase_blk(struct nvm_dev *dev, struct nvm_block *blk,
+							unsigned long flags)
+{
+	int plane_cnt = 0, pl_idx, ret;
+	struct ppa_addr addr;
+	struct nvm_rq rqd;
+
+	if (!dev->ops->erase_block)
+		return 0;
+
+	addr = block_to_ppa(dev, blk);
+
+	if (dev->plane_mode == NVM_PLANE_SINGLE) {
+		rqd.nr_pages = 1;
+		rqd.ppa_addr = addr;
+	} else {
+		plane_cnt = (1 << dev->plane_mode);
+		rqd.nr_pages = plane_cnt;
+
+		rqd.ppa_list = nvm_dev_dma_alloc(dev, GFP_KERNEL,
+							&rqd.dma_ppa_list);
+		if (!rqd.ppa_list) {
+			pr_err("gennvm: failed to allocate dma memory\n");
+			return -ENOMEM;
+		}
+
+		for (pl_idx = 0; pl_idx < plane_cnt; pl_idx++) {
+			addr.g.pl = pl_idx;
+			rqd.ppa_list[pl_idx] = addr;
+		}
+	}
+
+	gennvm_generic_to_addr_mode(dev, &rqd);
+
+	ret = dev->ops->erase_block(dev, &rqd);
+
+	if (plane_cnt)
+		nvm_dev_dma_free(dev, rqd.ppa_list, rqd.dma_ppa_list);
+
+	return ret;
+}
+
+static struct nvm_lun *gennvm_get_lun(struct nvm_dev *dev, int lunid)
+{
+	struct gen_nvm *gn = dev->mp;
+
+	return &gn->luns[lunid].vlun;
+}
+
+static void gennvm_lun_info_print(struct nvm_dev *dev)
+{
+	struct gen_nvm *gn = dev->mp;
+	struct gen_lun *lun;
+	unsigned int i;
+
+
+	gennvm_for_each_lun(gn, lun, i) {
+		spin_lock(&lun->vlun.lock);
+
+		pr_info("%s: lun%8u\t%u\t%u\t%u\n",
+				dev->name, i,
+				lun->vlun.nr_free_blocks,
+				lun->vlun.nr_inuse_blocks,
+				lun->vlun.nr_bad_blocks);
+
+		spin_unlock(&lun->vlun.lock);
+	}
+}
+
+static struct nvmm_type gennvm = {
+	.name		= "gennvm",
+	.version	= {0, 1, 0},
+
+	.register_mgr	= gennvm_register,
+	.unregister_mgr	= gennvm_unregister,
+
+	.get_blk	= gennvm_get_blk,
+	.put_blk	= gennvm_put_blk,
+
+	.submit_io	= gennvm_submit_io,
+	.end_io		= gennvm_end_io,
+	.erase_blk	= gennvm_erase_blk,
+
+	.get_lun	= gennvm_get_lun,
+	.lun_info_print = gennvm_lun_info_print,
+};
+
+static int __init gennvm_module_init(void)
+{
+	return nvm_register_mgr(&gennvm);
+}
+
+static void gennvm_module_exit(void)
+{
+	nvm_unregister_mgr(&gennvm);
+}
+
+module_init(gennvm_module_init);
+module_exit(gennvm_module_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Generic media manager for Open-Channel SSDs");
diff --git a/kernel/drivers/lightnvm/gennvm.h b/kernel/drivers/lightnvm/gennvm.h
new file mode 100644
index 000000000..9c24b5b32
--- /dev/null
+++ b/kernel/drivers/lightnvm/gennvm.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright: Matias Bjorling <mb@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.
+ *
+ */
+
+#ifndef GENNVM_H_
+#define GENNVM_H_
+
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+
+#include <linux/lightnvm.h>
+
+struct gen_lun {
+	struct nvm_lun vlun;
+
+	int reserved_blocks;
+	/* lun block lists */
+	struct list_head used_list;	/* In-use blocks */
+	struct list_head free_list;	/* Not used blocks i.e. released
+					 * and ready for use
+					 */
+	struct list_head bb_list;	/* Bad blocks. Mutually exclusive with
+					 * free_list and used_list
+					 */
+};
+
+struct gen_nvm {
+	struct nvm_dev *dev;
+
+	int nr_luns;
+	struct gen_lun *luns;
+};
+
+#define gennvm_for_each_lun(bm, lun, i) \
+		for ((i) = 0, lun = &(bm)->luns[0]; \
+			(i) < (bm)->nr_luns; (i)++, lun = &(bm)->luns[(i)])
+
+#endif /* GENNVM_H_ */
diff --git a/kernel/drivers/lightnvm/rrpc.c b/kernel/drivers/lightnvm/rrpc.c
new file mode 100644
index 000000000..134e4faba
--- /dev/null
+++ b/kernel/drivers/lightnvm/rrpc.c
@@ -0,0 +1,1371 @@
+/*
+ * Copyright (C) 2015 IT University of Copenhagen
+ * 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.
+ *
+ * Implementation of a Round-robin page-based Hybrid FTL for Open-channel SSDs.
+ */
+
+#include "rrpc.h"
+
+static struct kmem_cache *rrpc_gcb_cache, *rrpc_rq_cache;
+static DECLARE_RWSEM(rrpc_lock);
+
+static int rrpc_submit_io(struct rrpc *rrpc, struct bio *bio,
+				struct nvm_rq *rqd, unsigned long flags);
+
+#define rrpc_for_each_lun(rrpc, rlun, i) \
+		for ((i) = 0, rlun = &(rrpc)->luns[0]; \
+			(i) < (rrpc)->nr_luns; (i)++, rlun = &(rrpc)->luns[(i)])
+
+static void rrpc_page_invalidate(struct rrpc *rrpc, struct rrpc_addr *a)
+{
+	struct rrpc_block *rblk = a->rblk;
+	unsigned int pg_offset;
+
+	lockdep_assert_held(&rrpc->rev_lock);
+
+	if (a->addr == ADDR_EMPTY || !rblk)
+		return;
+
+	spin_lock(&rblk->lock);
+
+	div_u64_rem(a->addr, rrpc->dev->pgs_per_blk, &pg_offset);
+	WARN_ON(test_and_set_bit(pg_offset, rblk->invalid_pages));
+	rblk->nr_invalid_pages++;
+
+	spin_unlock(&rblk->lock);
+
+	rrpc->rev_trans_map[a->addr - rrpc->poffset].addr = ADDR_EMPTY;
+}
+
+static void rrpc_invalidate_range(struct rrpc *rrpc, sector_t slba,
+								unsigned len)
+{
+	sector_t i;
+
+	spin_lock(&rrpc->rev_lock);
+	for (i = slba; i < slba + len; i++) {
+		struct rrpc_addr *gp = &rrpc->trans_map[i];
+
+		rrpc_page_invalidate(rrpc, gp);
+		gp->rblk = NULL;
+	}
+	spin_unlock(&rrpc->rev_lock);
+}
+
+static struct nvm_rq *rrpc_inflight_laddr_acquire(struct rrpc *rrpc,
+					sector_t laddr, unsigned int pages)
+{
+	struct nvm_rq *rqd;
+	struct rrpc_inflight_rq *inf;
+
+	rqd = mempool_alloc(rrpc->rq_pool, GFP_ATOMIC);
+	if (!rqd)
+		return ERR_PTR(-ENOMEM);
+
+	inf = rrpc_get_inflight_rq(rqd);
+	if (rrpc_lock_laddr(rrpc, laddr, pages, inf)) {
+		mempool_free(rqd, rrpc->rq_pool);
+		return NULL;
+	}
+
+	return rqd;
+}
+
+static void rrpc_inflight_laddr_release(struct rrpc *rrpc, struct nvm_rq *rqd)
+{
+	struct rrpc_inflight_rq *inf = rrpc_get_inflight_rq(rqd);
+
+	rrpc_unlock_laddr(rrpc, inf);
+
+	mempool_free(rqd, rrpc->rq_pool);
+}
+
+static void rrpc_discard(struct rrpc *rrpc, struct bio *bio)
+{
+	sector_t slba = bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
+	sector_t len = bio->bi_iter.bi_size / RRPC_EXPOSED_PAGE_SIZE;
+	struct nvm_rq *rqd;
+
+	do {
+		rqd = rrpc_inflight_laddr_acquire(rrpc, slba, len);
+		schedule();
+	} while (!rqd);
+
+	if (IS_ERR(rqd)) {
+		pr_err("rrpc: unable to acquire inflight IO\n");
+		bio_io_error(bio);
+		return;
+	}
+
+	rrpc_invalidate_range(rrpc, slba, len);
+	rrpc_inflight_laddr_release(rrpc, rqd);
+}
+
+static int block_is_full(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+	return (rblk->next_page == rrpc->dev->pgs_per_blk);
+}
+
+static u64 block_to_addr(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+	struct nvm_block *blk = rblk->parent;
+
+	return blk->id * rrpc->dev->pgs_per_blk;
+}
+
+static struct ppa_addr linear_to_generic_addr(struct nvm_dev *dev,
+							struct ppa_addr r)
+{
+	struct ppa_addr l;
+	int secs, pgs, blks, luns;
+	sector_t ppa = r.ppa;
+
+	l.ppa = 0;
+
+	div_u64_rem(ppa, dev->sec_per_pg, &secs);
+	l.g.sec = secs;
+
+	sector_div(ppa, dev->sec_per_pg);
+	div_u64_rem(ppa, dev->sec_per_blk, &pgs);
+	l.g.pg = pgs;
+
+	sector_div(ppa, dev->pgs_per_blk);
+	div_u64_rem(ppa, dev->blks_per_lun, &blks);
+	l.g.blk = blks;
+
+	sector_div(ppa, dev->blks_per_lun);
+	div_u64_rem(ppa, dev->luns_per_chnl, &luns);
+	l.g.lun = luns;
+
+	sector_div(ppa, dev->luns_per_chnl);
+	l.g.ch = ppa;
+
+	return l;
+}
+
+static struct ppa_addr rrpc_ppa_to_gaddr(struct nvm_dev *dev, u64 addr)
+{
+	struct ppa_addr paddr;
+
+	paddr.ppa = addr;
+	return linear_to_generic_addr(dev, paddr);
+}
+
+/* requires lun->lock taken */
+static void rrpc_set_lun_cur(struct rrpc_lun *rlun, struct rrpc_block *rblk)
+{
+	struct rrpc *rrpc = rlun->rrpc;
+
+	BUG_ON(!rblk);
+
+	if (rlun->cur) {
+		spin_lock(&rlun->cur->lock);
+		WARN_ON(!block_is_full(rrpc, rlun->cur));
+		spin_unlock(&rlun->cur->lock);
+	}
+	rlun->cur = rblk;
+}
+
+static struct rrpc_block *rrpc_get_blk(struct rrpc *rrpc, struct rrpc_lun *rlun,
+							unsigned long flags)
+{
+	struct nvm_block *blk;
+	struct rrpc_block *rblk;
+
+	blk = nvm_get_blk(rrpc->dev, rlun->parent, flags);
+	if (!blk)
+		return NULL;
+
+	rblk = &rlun->blocks[blk->id];
+	blk->priv = rblk;
+
+	bitmap_zero(rblk->invalid_pages, rrpc->dev->pgs_per_blk);
+	rblk->next_page = 0;
+	rblk->nr_invalid_pages = 0;
+	atomic_set(&rblk->data_cmnt_size, 0);
+
+	return rblk;
+}
+
+static void rrpc_put_blk(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+	nvm_put_blk(rrpc->dev, rblk->parent);
+}
+
+static void rrpc_put_blks(struct rrpc *rrpc)
+{
+	struct rrpc_lun *rlun;
+	int i;
+
+	for (i = 0; i < rrpc->nr_luns; i++) {
+		rlun = &rrpc->luns[i];
+		if (rlun->cur)
+			rrpc_put_blk(rrpc, rlun->cur);
+		if (rlun->gc_cur)
+			rrpc_put_blk(rrpc, rlun->gc_cur);
+	}
+}
+
+static struct rrpc_lun *get_next_lun(struct rrpc *rrpc)
+{
+	int next = atomic_inc_return(&rrpc->next_lun);
+
+	return &rrpc->luns[next % rrpc->nr_luns];
+}
+
+static void rrpc_gc_kick(struct rrpc *rrpc)
+{
+	struct rrpc_lun *rlun;
+	unsigned int i;
+
+	for (i = 0; i < rrpc->nr_luns; i++) {
+		rlun = &rrpc->luns[i];
+		queue_work(rrpc->krqd_wq, &rlun->ws_gc);
+	}
+}
+
+/*
+ * timed GC every interval.
+ */
+static void rrpc_gc_timer(unsigned long data)
+{
+	struct rrpc *rrpc = (struct rrpc *)data;
+
+	rrpc_gc_kick(rrpc);
+	mod_timer(&rrpc->gc_timer, jiffies + msecs_to_jiffies(10));
+}
+
+static void rrpc_end_sync_bio(struct bio *bio)
+{
+	struct completion *waiting = bio->bi_private;
+
+	if (bio->bi_error)
+		pr_err("nvm: gc request failed (%u).\n", bio->bi_error);
+
+	complete(waiting);
+}
+
+/*
+ * rrpc_move_valid_pages -- migrate live data off the block
+ * @rrpc: the 'rrpc' structure
+ * @block: the block from which to migrate live pages
+ *
+ * Description:
+ *   GC algorithms may call this function to migrate remaining live
+ *   pages off the block prior to erasing it. This function blocks
+ *   further execution until the operation is complete.
+ */
+static int rrpc_move_valid_pages(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+	struct request_queue *q = rrpc->dev->q;
+	struct rrpc_rev_addr *rev;
+	struct nvm_rq *rqd;
+	struct bio *bio;
+	struct page *page;
+	int slot;
+	int nr_pgs_per_blk = rrpc->dev->pgs_per_blk;
+	u64 phys_addr;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	if (bitmap_full(rblk->invalid_pages, nr_pgs_per_blk))
+		return 0;
+
+	bio = bio_alloc(GFP_NOIO, 1);
+	if (!bio) {
+		pr_err("nvm: could not alloc bio to gc\n");
+		return -ENOMEM;
+	}
+
+	page = mempool_alloc(rrpc->page_pool, GFP_NOIO);
+
+	while ((slot = find_first_zero_bit(rblk->invalid_pages,
+					    nr_pgs_per_blk)) < nr_pgs_per_blk) {
+
+		/* Lock laddr */
+		phys_addr = (rblk->parent->id * nr_pgs_per_blk) + slot;
+
+try:
+		spin_lock(&rrpc->rev_lock);
+		/* Get logical address from physical to logical table */
+		rev = &rrpc->rev_trans_map[phys_addr - rrpc->poffset];
+		/* already updated by previous regular write */
+		if (rev->addr == ADDR_EMPTY) {
+			spin_unlock(&rrpc->rev_lock);
+			continue;
+		}
+
+		rqd = rrpc_inflight_laddr_acquire(rrpc, rev->addr, 1);
+		if (IS_ERR_OR_NULL(rqd)) {
+			spin_unlock(&rrpc->rev_lock);
+			schedule();
+			goto try;
+		}
+
+		spin_unlock(&rrpc->rev_lock);
+
+		/* Perform read to do GC */
+		bio->bi_iter.bi_sector = rrpc_get_sector(rev->addr);
+		bio->bi_rw = READ;
+		bio->bi_private = &wait;
+		bio->bi_end_io = rrpc_end_sync_bio;
+
+		/* TODO: may fail when EXP_PG_SIZE > PAGE_SIZE */
+		bio_add_pc_page(q, bio, page, RRPC_EXPOSED_PAGE_SIZE, 0);
+
+		if (rrpc_submit_io(rrpc, bio, rqd, NVM_IOTYPE_GC)) {
+			pr_err("rrpc: gc read failed.\n");
+			rrpc_inflight_laddr_release(rrpc, rqd);
+			goto finished;
+		}
+		wait_for_completion_io(&wait);
+
+		bio_reset(bio);
+		reinit_completion(&wait);
+
+		bio->bi_iter.bi_sector = rrpc_get_sector(rev->addr);
+		bio->bi_rw = WRITE;
+		bio->bi_private = &wait;
+		bio->bi_end_io = rrpc_end_sync_bio;
+
+		bio_add_pc_page(q, bio, page, RRPC_EXPOSED_PAGE_SIZE, 0);
+
+		/* turn the command around and write the data back to a new
+		 * address
+		 */
+		if (rrpc_submit_io(rrpc, bio, rqd, NVM_IOTYPE_GC)) {
+			pr_err("rrpc: gc write failed.\n");
+			rrpc_inflight_laddr_release(rrpc, rqd);
+			goto finished;
+		}
+		wait_for_completion_io(&wait);
+
+		rrpc_inflight_laddr_release(rrpc, rqd);
+
+		bio_reset(bio);
+	}
+
+finished:
+	mempool_free(page, rrpc->page_pool);
+	bio_put(bio);
+
+	if (!bitmap_full(rblk->invalid_pages, nr_pgs_per_blk)) {
+		pr_err("nvm: failed to garbage collect block\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static void rrpc_block_gc(struct work_struct *work)
+{
+	struct rrpc_block_gc *gcb = container_of(work, struct rrpc_block_gc,
+									ws_gc);
+	struct rrpc *rrpc = gcb->rrpc;
+	struct rrpc_block *rblk = gcb->rblk;
+	struct nvm_dev *dev = rrpc->dev;
+
+	pr_debug("nvm: block '%lu' being reclaimed\n", rblk->parent->id);
+
+	if (rrpc_move_valid_pages(rrpc, rblk))
+		goto done;
+
+	nvm_erase_blk(dev, rblk->parent);
+	rrpc_put_blk(rrpc, rblk);
+done:
+	mempool_free(gcb, rrpc->gcb_pool);
+}
+
+/* the block with highest number of invalid pages, will be in the beginning
+ * of the list
+ */
+static struct rrpc_block *rblock_max_invalid(struct rrpc_block *ra,
+							struct rrpc_block *rb)
+{
+	if (ra->nr_invalid_pages == rb->nr_invalid_pages)
+		return ra;
+
+	return (ra->nr_invalid_pages < rb->nr_invalid_pages) ? rb : ra;
+}
+
+/* linearly find the block with highest number of invalid pages
+ * requires lun->lock
+ */
+static struct rrpc_block *block_prio_find_max(struct rrpc_lun *rlun)
+{
+	struct list_head *prio_list = &rlun->prio_list;
+	struct rrpc_block *rblock, *max;
+
+	BUG_ON(list_empty(prio_list));
+
+	max = list_first_entry(prio_list, struct rrpc_block, prio);
+	list_for_each_entry(rblock, prio_list, prio)
+		max = rblock_max_invalid(max, rblock);
+
+	return max;
+}
+
+static void rrpc_lun_gc(struct work_struct *work)
+{
+	struct rrpc_lun *rlun = container_of(work, struct rrpc_lun, ws_gc);
+	struct rrpc *rrpc = rlun->rrpc;
+	struct nvm_lun *lun = rlun->parent;
+	struct rrpc_block_gc *gcb;
+	unsigned int nr_blocks_need;
+
+	nr_blocks_need = rrpc->dev->blks_per_lun / GC_LIMIT_INVERSE;
+
+	if (nr_blocks_need < rrpc->nr_luns)
+		nr_blocks_need = rrpc->nr_luns;
+
+	spin_lock(&lun->lock);
+	while (nr_blocks_need > lun->nr_free_blocks &&
+					!list_empty(&rlun->prio_list)) {
+		struct rrpc_block *rblock = block_prio_find_max(rlun);
+		struct nvm_block *block = rblock->parent;
+
+		if (!rblock->nr_invalid_pages)
+			break;
+
+		list_del_init(&rblock->prio);
+
+		BUG_ON(!block_is_full(rrpc, rblock));
+
+		pr_debug("rrpc: selected block '%lu' for GC\n", block->id);
+
+		gcb = mempool_alloc(rrpc->gcb_pool, GFP_ATOMIC);
+		if (!gcb)
+			break;
+
+		gcb->rrpc = rrpc;
+		gcb->rblk = rblock;
+		INIT_WORK(&gcb->ws_gc, rrpc_block_gc);
+
+		queue_work(rrpc->kgc_wq, &gcb->ws_gc);
+
+		nr_blocks_need--;
+	}
+	spin_unlock(&lun->lock);
+
+	/* TODO: Hint that request queue can be started again */
+}
+
+static void rrpc_gc_queue(struct work_struct *work)
+{
+	struct rrpc_block_gc *gcb = container_of(work, struct rrpc_block_gc,
+									ws_gc);
+	struct rrpc *rrpc = gcb->rrpc;
+	struct rrpc_block *rblk = gcb->rblk;
+	struct nvm_lun *lun = rblk->parent->lun;
+	struct rrpc_lun *rlun = &rrpc->luns[lun->id - rrpc->lun_offset];
+
+	spin_lock(&rlun->lock);
+	list_add_tail(&rblk->prio, &rlun->prio_list);
+	spin_unlock(&rlun->lock);
+
+	mempool_free(gcb, rrpc->gcb_pool);
+	pr_debug("nvm: block '%lu' is full, allow GC (sched)\n",
+							rblk->parent->id);
+}
+
+static const struct block_device_operations rrpc_fops = {
+	.owner		= THIS_MODULE,
+};
+
+static struct rrpc_lun *rrpc_get_lun_rr(struct rrpc *rrpc, int is_gc)
+{
+	unsigned int i;
+	struct rrpc_lun *rlun, *max_free;
+
+	if (!is_gc)
+		return get_next_lun(rrpc);
+
+	/* during GC, we don't care about RR, instead we want to make
+	 * sure that we maintain evenness between the block luns.
+	 */
+	max_free = &rrpc->luns[0];
+	/* prevent GC-ing lun from devouring pages of a lun with
+	 * little free blocks. We don't take the lock as we only need an
+	 * estimate.
+	 */
+	rrpc_for_each_lun(rrpc, rlun, i) {
+		if (rlun->parent->nr_free_blocks >
+					max_free->parent->nr_free_blocks)
+			max_free = rlun;
+	}
+
+	return max_free;
+}
+
+static struct rrpc_addr *rrpc_update_map(struct rrpc *rrpc, sector_t laddr,
+					struct rrpc_block *rblk, u64 paddr)
+{
+	struct rrpc_addr *gp;
+	struct rrpc_rev_addr *rev;
+
+	BUG_ON(laddr >= rrpc->nr_pages);
+
+	gp = &rrpc->trans_map[laddr];
+	spin_lock(&rrpc->rev_lock);
+	if (gp->rblk)
+		rrpc_page_invalidate(rrpc, gp);
+
+	gp->addr = paddr;
+	gp->rblk = rblk;
+
+	rev = &rrpc->rev_trans_map[gp->addr - rrpc->poffset];
+	rev->addr = laddr;
+	spin_unlock(&rrpc->rev_lock);
+
+	return gp;
+}
+
+static u64 rrpc_alloc_addr(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+	u64 addr = ADDR_EMPTY;
+
+	spin_lock(&rblk->lock);
+	if (block_is_full(rrpc, rblk))
+		goto out;
+
+	addr = block_to_addr(rrpc, rblk) + rblk->next_page;
+
+	rblk->next_page++;
+out:
+	spin_unlock(&rblk->lock);
+	return addr;
+}
+
+/* Simple round-robin Logical to physical address translation.
+ *
+ * Retrieve the mapping using the active append point. Then update the ap for
+ * the next write to the disk.
+ *
+ * Returns rrpc_addr with the physical address and block. Remember to return to
+ * rrpc->addr_cache when request is finished.
+ */
+static struct rrpc_addr *rrpc_map_page(struct rrpc *rrpc, sector_t laddr,
+								int is_gc)
+{
+	struct rrpc_lun *rlun;
+	struct rrpc_block *rblk;
+	struct nvm_lun *lun;
+	u64 paddr;
+
+	rlun = rrpc_get_lun_rr(rrpc, is_gc);
+	lun = rlun->parent;
+
+	if (!is_gc && lun->nr_free_blocks < rrpc->nr_luns * 4)
+		return NULL;
+
+	spin_lock(&rlun->lock);
+
+	rblk = rlun->cur;
+retry:
+	paddr = rrpc_alloc_addr(rrpc, rblk);
+
+	if (paddr == ADDR_EMPTY) {
+		rblk = rrpc_get_blk(rrpc, rlun, 0);
+		if (rblk) {
+			rrpc_set_lun_cur(rlun, rblk);
+			goto retry;
+		}
+
+		if (is_gc) {
+			/* retry from emergency gc block */
+			paddr = rrpc_alloc_addr(rrpc, rlun->gc_cur);
+			if (paddr == ADDR_EMPTY) {
+				rblk = rrpc_get_blk(rrpc, rlun, 1);
+				if (!rblk) {
+					pr_err("rrpc: no more blocks");
+					goto err;
+				}
+
+				rlun->gc_cur = rblk;
+				paddr = rrpc_alloc_addr(rrpc, rlun->gc_cur);
+			}
+			rblk = rlun->gc_cur;
+		}
+	}
+
+	spin_unlock(&rlun->lock);
+	return rrpc_update_map(rrpc, laddr, rblk, paddr);
+err:
+	spin_unlock(&rlun->lock);
+	return NULL;
+}
+
+static void rrpc_run_gc(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+	struct rrpc_block_gc *gcb;
+
+	gcb = mempool_alloc(rrpc->gcb_pool, GFP_ATOMIC);
+	if (!gcb) {
+		pr_err("rrpc: unable to queue block for gc.");
+		return;
+	}
+
+	gcb->rrpc = rrpc;
+	gcb->rblk = rblk;
+
+	INIT_WORK(&gcb->ws_gc, rrpc_gc_queue);
+	queue_work(rrpc->kgc_wq, &gcb->ws_gc);
+}
+
+static void rrpc_end_io_write(struct rrpc *rrpc, struct rrpc_rq *rrqd,
+						sector_t laddr, uint8_t npages)
+{
+	struct rrpc_addr *p;
+	struct rrpc_block *rblk;
+	struct nvm_lun *lun;
+	int cmnt_size, i;
+
+	for (i = 0; i < npages; i++) {
+		p = &rrpc->trans_map[laddr + i];
+		rblk = p->rblk;
+		lun = rblk->parent->lun;
+
+		cmnt_size = atomic_inc_return(&rblk->data_cmnt_size);
+		if (unlikely(cmnt_size == rrpc->dev->pgs_per_blk))
+			rrpc_run_gc(rrpc, rblk);
+	}
+}
+
+static int rrpc_end_io(struct nvm_rq *rqd, int error)
+{
+	struct rrpc *rrpc = container_of(rqd->ins, struct rrpc, instance);
+	struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
+	uint8_t npages = rqd->nr_pages;
+	sector_t laddr = rrpc_get_laddr(rqd->bio) - npages;
+
+	if (bio_data_dir(rqd->bio) == WRITE)
+		rrpc_end_io_write(rrpc, rrqd, laddr, npages);
+
+	if (rrqd->flags & NVM_IOTYPE_GC)
+		return 0;
+
+	rrpc_unlock_rq(rrpc, rqd);
+	bio_put(rqd->bio);
+
+	if (npages > 1)
+		nvm_dev_dma_free(rrpc->dev, rqd->ppa_list, rqd->dma_ppa_list);
+	if (rqd->metadata)
+		nvm_dev_dma_free(rrpc->dev, rqd->metadata, rqd->dma_metadata);
+
+	mempool_free(rqd, rrpc->rq_pool);
+
+	return 0;
+}
+
+static int rrpc_read_ppalist_rq(struct rrpc *rrpc, struct bio *bio,
+			struct nvm_rq *rqd, unsigned long flags, int npages)
+{
+	struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
+	struct rrpc_addr *gp;
+	sector_t laddr = rrpc_get_laddr(bio);
+	int is_gc = flags & NVM_IOTYPE_GC;
+	int i;
+
+	if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd)) {
+		nvm_dev_dma_free(rrpc->dev, rqd->ppa_list, rqd->dma_ppa_list);
+		return NVM_IO_REQUEUE;
+	}
+
+	for (i = 0; i < npages; i++) {
+		/* We assume that mapping occurs at 4KB granularity */
+		BUG_ON(!(laddr + i >= 0 && laddr + i < rrpc->nr_pages));
+		gp = &rrpc->trans_map[laddr + i];
+
+		if (gp->rblk) {
+			rqd->ppa_list[i] = rrpc_ppa_to_gaddr(rrpc->dev,
+								gp->addr);
+		} else {
+			BUG_ON(is_gc);
+			rrpc_unlock_laddr(rrpc, r);
+			nvm_dev_dma_free(rrpc->dev, rqd->ppa_list,
+							rqd->dma_ppa_list);
+			return NVM_IO_DONE;
+		}
+	}
+
+	rqd->opcode = NVM_OP_HBREAD;
+
+	return NVM_IO_OK;
+}
+
+static int rrpc_read_rq(struct rrpc *rrpc, struct bio *bio, struct nvm_rq *rqd,
+							unsigned long flags)
+{
+	struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
+	int is_gc = flags & NVM_IOTYPE_GC;
+	sector_t laddr = rrpc_get_laddr(bio);
+	struct rrpc_addr *gp;
+
+	if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd))
+		return NVM_IO_REQUEUE;
+
+	BUG_ON(!(laddr >= 0 && laddr < rrpc->nr_pages));
+	gp = &rrpc->trans_map[laddr];
+
+	if (gp->rblk) {
+		rqd->ppa_addr = rrpc_ppa_to_gaddr(rrpc->dev, gp->addr);
+	} else {
+		BUG_ON(is_gc);
+		rrpc_unlock_rq(rrpc, rqd);
+		return NVM_IO_DONE;
+	}
+
+	rqd->opcode = NVM_OP_HBREAD;
+	rrqd->addr = gp;
+
+	return NVM_IO_OK;
+}
+
+static int rrpc_write_ppalist_rq(struct rrpc *rrpc, struct bio *bio,
+			struct nvm_rq *rqd, unsigned long flags, int npages)
+{
+	struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
+	struct rrpc_addr *p;
+	sector_t laddr = rrpc_get_laddr(bio);
+	int is_gc = flags & NVM_IOTYPE_GC;
+	int i;
+
+	if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd)) {
+		nvm_dev_dma_free(rrpc->dev, rqd->ppa_list, rqd->dma_ppa_list);
+		return NVM_IO_REQUEUE;
+	}
+
+	for (i = 0; i < npages; i++) {
+		/* We assume that mapping occurs at 4KB granularity */
+		p = rrpc_map_page(rrpc, laddr + i, is_gc);
+		if (!p) {
+			BUG_ON(is_gc);
+			rrpc_unlock_laddr(rrpc, r);
+			nvm_dev_dma_free(rrpc->dev, rqd->ppa_list,
+							rqd->dma_ppa_list);
+			rrpc_gc_kick(rrpc);
+			return NVM_IO_REQUEUE;
+		}
+
+		rqd->ppa_list[i] = rrpc_ppa_to_gaddr(rrpc->dev,
+								p->addr);
+	}
+
+	rqd->opcode = NVM_OP_HBWRITE;
+
+	return NVM_IO_OK;
+}
+
+static int rrpc_write_rq(struct rrpc *rrpc, struct bio *bio,
+				struct nvm_rq *rqd, unsigned long flags)
+{
+	struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
+	struct rrpc_addr *p;
+	int is_gc = flags & NVM_IOTYPE_GC;
+	sector_t laddr = rrpc_get_laddr(bio);
+
+	if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd))
+		return NVM_IO_REQUEUE;
+
+	p = rrpc_map_page(rrpc, laddr, is_gc);
+	if (!p) {
+		BUG_ON(is_gc);
+		rrpc_unlock_rq(rrpc, rqd);
+		rrpc_gc_kick(rrpc);
+		return NVM_IO_REQUEUE;
+	}
+
+	rqd->ppa_addr = rrpc_ppa_to_gaddr(rrpc->dev, p->addr);
+	rqd->opcode = NVM_OP_HBWRITE;
+	rrqd->addr = p;
+
+	return NVM_IO_OK;
+}
+
+static int rrpc_setup_rq(struct rrpc *rrpc, struct bio *bio,
+			struct nvm_rq *rqd, unsigned long flags, uint8_t npages)
+{
+	if (npages > 1) {
+		rqd->ppa_list = nvm_dev_dma_alloc(rrpc->dev, GFP_KERNEL,
+							&rqd->dma_ppa_list);
+		if (!rqd->ppa_list) {
+			pr_err("rrpc: not able to allocate ppa list\n");
+			return NVM_IO_ERR;
+		}
+
+		if (bio_rw(bio) == WRITE)
+			return rrpc_write_ppalist_rq(rrpc, bio, rqd, flags,
+									npages);
+
+		return rrpc_read_ppalist_rq(rrpc, bio, rqd, flags, npages);
+	}
+
+	if (bio_rw(bio) == WRITE)
+		return rrpc_write_rq(rrpc, bio, rqd, flags);
+
+	return rrpc_read_rq(rrpc, bio, rqd, flags);
+}
+
+static int rrpc_submit_io(struct rrpc *rrpc, struct bio *bio,
+				struct nvm_rq *rqd, unsigned long flags)
+{
+	int err;
+	struct rrpc_rq *rrq = nvm_rq_to_pdu(rqd);
+	uint8_t nr_pages = rrpc_get_pages(bio);
+	int bio_size = bio_sectors(bio) << 9;
+
+	if (bio_size < rrpc->dev->sec_size)
+		return NVM_IO_ERR;
+	else if (bio_size > rrpc->dev->max_rq_size)
+		return NVM_IO_ERR;
+
+	err = rrpc_setup_rq(rrpc, bio, rqd, flags, nr_pages);
+	if (err)
+		return err;
+
+	bio_get(bio);
+	rqd->bio = bio;
+	rqd->ins = &rrpc->instance;
+	rqd->nr_pages = nr_pages;
+	rrq->flags = flags;
+
+	err = nvm_submit_io(rrpc->dev, rqd);
+	if (err) {
+		pr_err("rrpc: I/O submission failed: %d\n", err);
+		return NVM_IO_ERR;
+	}
+
+	return NVM_IO_OK;
+}
+
+static blk_qc_t rrpc_make_rq(struct request_queue *q, struct bio *bio)
+{
+	struct rrpc *rrpc = q->queuedata;
+	struct nvm_rq *rqd;
+	int err;
+
+	if (bio->bi_rw & REQ_DISCARD) {
+		rrpc_discard(rrpc, bio);
+		return BLK_QC_T_NONE;
+	}
+
+	rqd = mempool_alloc(rrpc->rq_pool, GFP_KERNEL);
+	if (!rqd) {
+		pr_err_ratelimited("rrpc: not able to queue bio.");
+		bio_io_error(bio);
+		return BLK_QC_T_NONE;
+	}
+	memset(rqd, 0, sizeof(struct nvm_rq));
+
+	err = rrpc_submit_io(rrpc, bio, rqd, NVM_IOTYPE_NONE);
+	switch (err) {
+	case NVM_IO_OK:
+		return BLK_QC_T_NONE;
+	case NVM_IO_ERR:
+		bio_io_error(bio);
+		break;
+	case NVM_IO_DONE:
+		bio_endio(bio);
+		break;
+	case NVM_IO_REQUEUE:
+		spin_lock(&rrpc->bio_lock);
+		bio_list_add(&rrpc->requeue_bios, bio);
+		spin_unlock(&rrpc->bio_lock);
+		queue_work(rrpc->kgc_wq, &rrpc->ws_requeue);
+		break;
+	}
+
+	mempool_free(rqd, rrpc->rq_pool);
+	return BLK_QC_T_NONE;
+}
+
+static void rrpc_requeue(struct work_struct *work)
+{
+	struct rrpc *rrpc = container_of(work, struct rrpc, ws_requeue);
+	struct bio_list bios;
+	struct bio *bio;
+
+	bio_list_init(&bios);
+
+	spin_lock(&rrpc->bio_lock);
+	bio_list_merge(&bios, &rrpc->requeue_bios);
+	bio_list_init(&rrpc->requeue_bios);
+	spin_unlock(&rrpc->bio_lock);
+
+	while ((bio = bio_list_pop(&bios)))
+		rrpc_make_rq(rrpc->disk->queue, bio);
+}
+
+static void rrpc_gc_free(struct rrpc *rrpc)
+{
+	struct rrpc_lun *rlun;
+	int i;
+
+	if (rrpc->krqd_wq)
+		destroy_workqueue(rrpc->krqd_wq);
+
+	if (rrpc->kgc_wq)
+		destroy_workqueue(rrpc->kgc_wq);
+
+	if (!rrpc->luns)
+		return;
+
+	for (i = 0; i < rrpc->nr_luns; i++) {
+		rlun = &rrpc->luns[i];
+
+		if (!rlun->blocks)
+			break;
+		vfree(rlun->blocks);
+	}
+}
+
+static int rrpc_gc_init(struct rrpc *rrpc)
+{
+	rrpc->krqd_wq = alloc_workqueue("rrpc-lun", WQ_MEM_RECLAIM|WQ_UNBOUND,
+								rrpc->nr_luns);
+	if (!rrpc->krqd_wq)
+		return -ENOMEM;
+
+	rrpc->kgc_wq = alloc_workqueue("rrpc-bg", WQ_MEM_RECLAIM, 1);
+	if (!rrpc->kgc_wq)
+		return -ENOMEM;
+
+	setup_timer(&rrpc->gc_timer, rrpc_gc_timer, (unsigned long)rrpc);
+
+	return 0;
+}
+
+static void rrpc_map_free(struct rrpc *rrpc)
+{
+	vfree(rrpc->rev_trans_map);
+	vfree(rrpc->trans_map);
+}
+
+static int rrpc_l2p_update(u64 slba, u32 nlb, __le64 *entries, void *private)
+{
+	struct rrpc *rrpc = (struct rrpc *)private;
+	struct nvm_dev *dev = rrpc->dev;
+	struct rrpc_addr *addr = rrpc->trans_map + slba;
+	struct rrpc_rev_addr *raddr = rrpc->rev_trans_map;
+	sector_t max_pages = dev->total_pages * (dev->sec_size >> 9);
+	u64 elba = slba + nlb;
+	u64 i;
+
+	if (unlikely(elba > dev->total_pages)) {
+		pr_err("nvm: L2P data from device is out of bounds!\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < nlb; i++) {
+		u64 pba = le64_to_cpu(entries[i]);
+		/* LNVM treats address-spaces as silos, LBA and PBA are
+		 * equally large and zero-indexed.
+		 */
+		if (unlikely(pba >= max_pages && pba != U64_MAX)) {
+			pr_err("nvm: L2P data entry is out of bounds!\n");
+			return -EINVAL;
+		}
+
+		/* Address zero is a special one. The first page on a disk is
+		 * protected. As it often holds internal device boot
+		 * information.
+		 */
+		if (!pba)
+			continue;
+
+		addr[i].addr = pba;
+		raddr[pba].addr = slba + i;
+	}
+
+	return 0;
+}
+
+static int rrpc_map_init(struct rrpc *rrpc)
+{
+	struct nvm_dev *dev = rrpc->dev;
+	sector_t i;
+	int ret;
+
+	rrpc->trans_map = vzalloc(sizeof(struct rrpc_addr) * rrpc->nr_pages);
+	if (!rrpc->trans_map)
+		return -ENOMEM;
+
+	rrpc->rev_trans_map = vmalloc(sizeof(struct rrpc_rev_addr)
+							* rrpc->nr_pages);
+	if (!rrpc->rev_trans_map)
+		return -ENOMEM;
+
+	for (i = 0; i < rrpc->nr_pages; i++) {
+		struct rrpc_addr *p = &rrpc->trans_map[i];
+		struct rrpc_rev_addr *r = &rrpc->rev_trans_map[i];
+
+		p->addr = ADDR_EMPTY;
+		r->addr = ADDR_EMPTY;
+	}
+
+	if (!dev->ops->get_l2p_tbl)
+		return 0;
+
+	/* Bring up the mapping table from device */
+	ret = dev->ops->get_l2p_tbl(dev, 0, dev->total_pages,
+							rrpc_l2p_update, rrpc);
+	if (ret) {
+		pr_err("nvm: rrpc: could not read L2P table.\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+
+/* Minimum pages needed within a lun */
+#define PAGE_POOL_SIZE 16
+#define ADDR_POOL_SIZE 64
+
+static int rrpc_core_init(struct rrpc *rrpc)
+{
+	down_write(&rrpc_lock);
+	if (!rrpc_gcb_cache) {
+		rrpc_gcb_cache = kmem_cache_create("rrpc_gcb",
+				sizeof(struct rrpc_block_gc), 0, 0, NULL);
+		if (!rrpc_gcb_cache) {
+			up_write(&rrpc_lock);
+			return -ENOMEM;
+		}
+
+		rrpc_rq_cache = kmem_cache_create("rrpc_rq",
+				sizeof(struct nvm_rq) + sizeof(struct rrpc_rq),
+				0, 0, NULL);
+		if (!rrpc_rq_cache) {
+			kmem_cache_destroy(rrpc_gcb_cache);
+			up_write(&rrpc_lock);
+			return -ENOMEM;
+		}
+	}
+	up_write(&rrpc_lock);
+
+	rrpc->page_pool = mempool_create_page_pool(PAGE_POOL_SIZE, 0);
+	if (!rrpc->page_pool)
+		return -ENOMEM;
+
+	rrpc->gcb_pool = mempool_create_slab_pool(rrpc->dev->nr_luns,
+								rrpc_gcb_cache);
+	if (!rrpc->gcb_pool)
+		return -ENOMEM;
+
+	rrpc->rq_pool = mempool_create_slab_pool(64, rrpc_rq_cache);
+	if (!rrpc->rq_pool)
+		return -ENOMEM;
+
+	spin_lock_init(&rrpc->inflights.lock);
+	INIT_LIST_HEAD(&rrpc->inflights.reqs);
+
+	return 0;
+}
+
+static void rrpc_core_free(struct rrpc *rrpc)
+{
+	mempool_destroy(rrpc->page_pool);
+	mempool_destroy(rrpc->gcb_pool);
+	mempool_destroy(rrpc->rq_pool);
+}
+
+static void rrpc_luns_free(struct rrpc *rrpc)
+{
+	kfree(rrpc->luns);
+}
+
+static int rrpc_luns_init(struct rrpc *rrpc, int lun_begin, int lun_end)
+{
+	struct nvm_dev *dev = rrpc->dev;
+	struct rrpc_lun *rlun;
+	int i, j;
+
+	spin_lock_init(&rrpc->rev_lock);
+
+	rrpc->luns = kcalloc(rrpc->nr_luns, sizeof(struct rrpc_lun),
+								GFP_KERNEL);
+	if (!rrpc->luns)
+		return -ENOMEM;
+
+	/* 1:1 mapping */
+	for (i = 0; i < rrpc->nr_luns; i++) {
+		struct nvm_lun *lun = dev->mt->get_lun(dev, lun_begin + i);
+
+		if (dev->pgs_per_blk >
+				MAX_INVALID_PAGES_STORAGE * BITS_PER_LONG) {
+			pr_err("rrpc: number of pages per block too high.");
+			goto err;
+		}
+
+		rlun = &rrpc->luns[i];
+		rlun->rrpc = rrpc;
+		rlun->parent = lun;
+		INIT_LIST_HEAD(&rlun->prio_list);
+		INIT_WORK(&rlun->ws_gc, rrpc_lun_gc);
+		spin_lock_init(&rlun->lock);
+
+		rrpc->total_blocks += dev->blks_per_lun;
+		rrpc->nr_pages += dev->sec_per_lun;
+
+		rlun->blocks = vzalloc(sizeof(struct rrpc_block) *
+						rrpc->dev->blks_per_lun);
+		if (!rlun->blocks)
+			goto err;
+
+		for (j = 0; j < rrpc->dev->blks_per_lun; j++) {
+			struct rrpc_block *rblk = &rlun->blocks[j];
+			struct nvm_block *blk = &lun->blocks[j];
+
+			rblk->parent = blk;
+			INIT_LIST_HEAD(&rblk->prio);
+			spin_lock_init(&rblk->lock);
+		}
+	}
+
+	return 0;
+err:
+	return -ENOMEM;
+}
+
+static void rrpc_free(struct rrpc *rrpc)
+{
+	rrpc_gc_free(rrpc);
+	rrpc_map_free(rrpc);
+	rrpc_core_free(rrpc);
+	rrpc_luns_free(rrpc);
+
+	kfree(rrpc);
+}
+
+static void rrpc_exit(void *private)
+{
+	struct rrpc *rrpc = private;
+
+	del_timer(&rrpc->gc_timer);
+
+	flush_workqueue(rrpc->krqd_wq);
+	flush_workqueue(rrpc->kgc_wq);
+
+	rrpc_free(rrpc);
+}
+
+static sector_t rrpc_capacity(void *private)
+{
+	struct rrpc *rrpc = private;
+	struct nvm_dev *dev = rrpc->dev;
+	sector_t reserved, provisioned;
+
+	/* cur, gc, and two emergency blocks for each lun */
+	reserved = rrpc->nr_luns * dev->max_pages_per_blk * 4;
+	provisioned = rrpc->nr_pages - reserved;
+
+	if (reserved > rrpc->nr_pages) {
+		pr_err("rrpc: not enough space available to expose storage.\n");
+		return 0;
+	}
+
+	sector_div(provisioned, 10);
+	return provisioned * 9 * NR_PHY_IN_LOG;
+}
+
+/*
+ * Looks up the logical address from reverse trans map and check if its valid by
+ * comparing the logical to physical address with the physical address.
+ * Returns 0 on free, otherwise 1 if in use
+ */
+static void rrpc_block_map_update(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+	struct nvm_dev *dev = rrpc->dev;
+	int offset;
+	struct rrpc_addr *laddr;
+	u64 paddr, pladdr;
+
+	for (offset = 0; offset < dev->pgs_per_blk; offset++) {
+		paddr = block_to_addr(rrpc, rblk) + offset;
+
+		pladdr = rrpc->rev_trans_map[paddr].addr;
+		if (pladdr == ADDR_EMPTY)
+			continue;
+
+		laddr = &rrpc->trans_map[pladdr];
+
+		if (paddr == laddr->addr) {
+			laddr->rblk = rblk;
+		} else {
+			set_bit(offset, rblk->invalid_pages);
+			rblk->nr_invalid_pages++;
+		}
+	}
+}
+
+static int rrpc_blocks_init(struct rrpc *rrpc)
+{
+	struct rrpc_lun *rlun;
+	struct rrpc_block *rblk;
+	int lun_iter, blk_iter;
+
+	for (lun_iter = 0; lun_iter < rrpc->nr_luns; lun_iter++) {
+		rlun = &rrpc->luns[lun_iter];
+
+		for (blk_iter = 0; blk_iter < rrpc->dev->blks_per_lun;
+								blk_iter++) {
+			rblk = &rlun->blocks[blk_iter];
+			rrpc_block_map_update(rrpc, rblk);
+		}
+	}
+
+	return 0;
+}
+
+static int rrpc_luns_configure(struct rrpc *rrpc)
+{
+	struct rrpc_lun *rlun;
+	struct rrpc_block *rblk;
+	int i;
+
+	for (i = 0; i < rrpc->nr_luns; i++) {
+		rlun = &rrpc->luns[i];
+
+		rblk = rrpc_get_blk(rrpc, rlun, 0);
+		if (!rblk)
+			goto err;
+
+		rrpc_set_lun_cur(rlun, rblk);
+
+		/* Emergency gc block */
+		rblk = rrpc_get_blk(rrpc, rlun, 1);
+		if (!rblk)
+			goto err;
+		rlun->gc_cur = rblk;
+	}
+
+	return 0;
+err:
+	rrpc_put_blks(rrpc);
+	return -EINVAL;
+}
+
+static struct nvm_tgt_type tt_rrpc;
+
+static void *rrpc_init(struct nvm_dev *dev, struct gendisk *tdisk,
+						int lun_begin, int lun_end)
+{
+	struct request_queue *bqueue = dev->q;
+	struct request_queue *tqueue = tdisk->queue;
+	struct rrpc *rrpc;
+	int ret;
+
+	if (!(dev->identity.dom & NVM_RSP_L2P)) {
+		pr_err("nvm: rrpc: device does not support l2p (%x)\n",
+							dev->identity.dom);
+		return ERR_PTR(-EINVAL);
+	}
+
+	rrpc = kzalloc(sizeof(struct rrpc), GFP_KERNEL);
+	if (!rrpc)
+		return ERR_PTR(-ENOMEM);
+
+	rrpc->instance.tt = &tt_rrpc;
+	rrpc->dev = dev;
+	rrpc->disk = tdisk;
+
+	bio_list_init(&rrpc->requeue_bios);
+	spin_lock_init(&rrpc->bio_lock);
+	INIT_WORK(&rrpc->ws_requeue, rrpc_requeue);
+
+	rrpc->nr_luns = lun_end - lun_begin + 1;
+
+	/* simple round-robin strategy */
+	atomic_set(&rrpc->next_lun, -1);
+
+	ret = rrpc_luns_init(rrpc, lun_begin, lun_end);
+	if (ret) {
+		pr_err("nvm: rrpc: could not initialize luns\n");
+		goto err;
+	}
+
+	rrpc->poffset = dev->sec_per_lun * lun_begin;
+	rrpc->lun_offset = lun_begin;
+
+	ret = rrpc_core_init(rrpc);
+	if (ret) {
+		pr_err("nvm: rrpc: could not initialize core\n");
+		goto err;
+	}
+
+	ret = rrpc_map_init(rrpc);
+	if (ret) {
+		pr_err("nvm: rrpc: could not initialize maps\n");
+		goto err;
+	}
+
+	ret = rrpc_blocks_init(rrpc);
+	if (ret) {
+		pr_err("nvm: rrpc: could not initialize state for blocks\n");
+		goto err;
+	}
+
+	ret = rrpc_luns_configure(rrpc);
+	if (ret) {
+		pr_err("nvm: rrpc: not enough blocks available in LUNs.\n");
+		goto err;
+	}
+
+	ret = rrpc_gc_init(rrpc);
+	if (ret) {
+		pr_err("nvm: rrpc: could not initialize gc\n");
+		goto err;
+	}
+
+	/* 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));
+
+	pr_info("nvm: rrpc initialized with %u luns and %llu pages.\n",
+			rrpc->nr_luns, (unsigned long long)rrpc->nr_pages);
+
+	mod_timer(&rrpc->gc_timer, jiffies + msecs_to_jiffies(10));
+
+	return rrpc;
+err:
+	rrpc_free(rrpc);
+	return ERR_PTR(ret);
+}
+
+/* round robin, page-based FTL, and cost-based GC */
+static struct nvm_tgt_type tt_rrpc = {
+	.name		= "rrpc",
+	.version	= {1, 0, 0},
+
+	.make_rq	= rrpc_make_rq,
+	.capacity	= rrpc_capacity,
+	.end_io		= rrpc_end_io,
+
+	.init		= rrpc_init,
+	.exit		= rrpc_exit,
+};
+
+static int __init rrpc_module_init(void)
+{
+	return nvm_register_target(&tt_rrpc);
+}
+
+static void rrpc_module_exit(void)
+{
+	nvm_unregister_target(&tt_rrpc);
+}
+
+module_init(rrpc_module_init);
+module_exit(rrpc_module_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Block-Device Target for Open-Channel SSDs");
diff --git a/kernel/drivers/lightnvm/rrpc.h b/kernel/drivers/lightnvm/rrpc.h
new file mode 100644
index 000000000..a9696a06c
--- /dev/null
+++ b/kernel/drivers/lightnvm/rrpc.h
@@ -0,0 +1,239 @@
+/*
+ * Copyright (C) 2015 IT University of Copenhagen
+ * 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.
+ *
+ * Implementation of a Round-robin page-based Hybrid FTL for Open-channel SSDs.
+ */
+
+#ifndef RRPC_H_
+#define RRPC_H_
+
+#include <linux/blkdev.h>
+#include <linux/blk-mq.h>
+#include <linux/bio.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/vmalloc.h>
+
+#include <linux/lightnvm.h>
+
+/* Run only GC if less than 1/X blocks are free */
+#define GC_LIMIT_INVERSE 10
+#define GC_TIME_SECS 100
+
+#define RRPC_SECTOR (512)
+#define RRPC_EXPOSED_PAGE_SIZE (4096)
+
+#define NR_PHY_IN_LOG (RRPC_EXPOSED_PAGE_SIZE / RRPC_SECTOR)
+
+struct rrpc_inflight {
+	struct list_head reqs;
+	spinlock_t lock;
+};
+
+struct rrpc_inflight_rq {
+	struct list_head list;
+	sector_t l_start;
+	sector_t l_end;
+};
+
+struct rrpc_rq {
+	struct rrpc_inflight_rq inflight_rq;
+	struct rrpc_addr *addr;
+	unsigned long flags;
+};
+
+struct rrpc_block {
+	struct nvm_block *parent;
+	struct list_head prio;
+
+#define MAX_INVALID_PAGES_STORAGE 8
+	/* Bitmap for invalid page intries */
+	unsigned long invalid_pages[MAX_INVALID_PAGES_STORAGE];
+	/* points to the next writable page within a block */
+	unsigned int next_page;
+	/* number of pages that are invalid, wrt host page size */
+	unsigned int nr_invalid_pages;
+
+	spinlock_t lock;
+	atomic_t data_cmnt_size; /* data pages committed to stable storage */
+};
+
+struct rrpc_lun {
+	struct rrpc *rrpc;
+	struct nvm_lun *parent;
+	struct rrpc_block *cur, *gc_cur;
+	struct rrpc_block *blocks;	/* Reference to block allocation */
+	struct list_head prio_list;		/* Blocks that may be GC'ed */
+	struct work_struct ws_gc;
+
+	spinlock_t lock;
+};
+
+struct rrpc {
+	/* instance must be kept in top to resolve rrpc in unprep */
+	struct nvm_tgt_instance instance;
+
+	struct nvm_dev *dev;
+	struct gendisk *disk;
+
+	u64 poffset; /* physical page offset */
+	int lun_offset;
+
+	int nr_luns;
+	struct rrpc_lun *luns;
+
+	/* calculated values */
+	unsigned long long nr_pages;
+	unsigned long total_blocks;
+
+	/* Write strategy variables. Move these into each for structure for each
+	 * strategy
+	 */
+	atomic_t next_lun; /* Whenever a page is written, this is updated
+			    * to point to the next write lun
+			    */
+
+	spinlock_t bio_lock;
+	struct bio_list requeue_bios;
+	struct work_struct ws_requeue;
+
+	/* Simple translation map of logical addresses to physical addresses.
+	 * The logical addresses is known by the host system, while the physical
+	 * addresses are used when writing to the disk block device.
+	 */
+	struct rrpc_addr *trans_map;
+	/* also store a reverse map for garbage collection */
+	struct rrpc_rev_addr *rev_trans_map;
+	spinlock_t rev_lock;
+
+	struct rrpc_inflight inflights;
+
+	mempool_t *addr_pool;
+	mempool_t *page_pool;
+	mempool_t *gcb_pool;
+	mempool_t *rq_pool;
+
+	struct timer_list gc_timer;
+	struct workqueue_struct *krqd_wq;
+	struct workqueue_struct *kgc_wq;
+};
+
+struct rrpc_block_gc {
+	struct rrpc *rrpc;
+	struct rrpc_block *rblk;
+	struct work_struct ws_gc;
+};
+
+/* Logical to physical mapping */
+struct rrpc_addr {
+	u64 addr;
+	struct rrpc_block *rblk;
+};
+
+/* Physical to logical mapping */
+struct rrpc_rev_addr {
+	u64 addr;
+};
+
+static inline sector_t rrpc_get_laddr(struct bio *bio)
+{
+	return bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
+}
+
+static inline unsigned int rrpc_get_pages(struct bio *bio)
+{
+	return  bio->bi_iter.bi_size / RRPC_EXPOSED_PAGE_SIZE;
+}
+
+static inline sector_t rrpc_get_sector(sector_t laddr)
+{
+	return laddr * NR_PHY_IN_LOG;
+}
+
+static inline int request_intersects(struct rrpc_inflight_rq *r,
+				sector_t laddr_start, sector_t laddr_end)
+{
+	return (laddr_end >= r->l_start && laddr_end <= r->l_end) &&
+		(laddr_start >= r->l_start && laddr_start <= r->l_end);
+}
+
+static int __rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
+			     unsigned pages, struct rrpc_inflight_rq *r)
+{
+	sector_t laddr_end = laddr + pages - 1;
+	struct rrpc_inflight_rq *rtmp;
+
+	spin_lock_irq(&rrpc->inflights.lock);
+	list_for_each_entry(rtmp, &rrpc->inflights.reqs, list) {
+		if (unlikely(request_intersects(rtmp, laddr, laddr_end))) {
+			/* existing, overlapping request, come back later */
+			spin_unlock_irq(&rrpc->inflights.lock);
+			return 1;
+		}
+	}
+
+	r->l_start = laddr;
+	r->l_end = laddr_end;
+
+	list_add_tail(&r->list, &rrpc->inflights.reqs);
+	spin_unlock_irq(&rrpc->inflights.lock);
+	return 0;
+}
+
+static inline int rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
+				 unsigned pages,
+				 struct rrpc_inflight_rq *r)
+{
+	BUG_ON((laddr + pages) > rrpc->nr_pages);
+
+	return __rrpc_lock_laddr(rrpc, laddr, pages, r);
+}
+
+static inline struct rrpc_inflight_rq *rrpc_get_inflight_rq(struct nvm_rq *rqd)
+{
+	struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
+
+	return &rrqd->inflight_rq;
+}
+
+static inline int rrpc_lock_rq(struct rrpc *rrpc, struct bio *bio,
+							struct nvm_rq *rqd)
+{
+	sector_t laddr = rrpc_get_laddr(bio);
+	unsigned int pages = rrpc_get_pages(bio);
+	struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
+
+	return rrpc_lock_laddr(rrpc, laddr, pages, r);
+}
+
+static inline void rrpc_unlock_laddr(struct rrpc *rrpc,
+						struct rrpc_inflight_rq *r)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&rrpc->inflights.lock, flags);
+	list_del_init(&r->list);
+	spin_unlock_irqrestore(&rrpc->inflights.lock, flags);
+}
+
+static inline void rrpc_unlock_rq(struct rrpc *rrpc, struct nvm_rq *rqd)
+{
+	struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
+	uint8_t pages = rqd->nr_pages;
+
+	BUG_ON((r->l_start + pages) > rrpc->nr_pages);
+
+	rrpc_unlock_laddr(rrpc, r);
+}
+
+#endif /* RRPC_H_ */