linux_kernel/drivers/nvme/host/core.c

/*
 * NVM Express device driver
 * Copyright (c) 2011-2014, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.
 */

#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/hdreg.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/list_sort.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/pr.h>
#include <linux/ptrace.h>
#include <linux/nvme_ioctl.h>
#include <linux/t10-pi.h>
#include <linux/pm_qos.h>
#include <asm/unaligned.h>

#define CREATE_TRACE_POINTS
#include "trace.h"

#include "nvme.h"
#include "fabrics.h"

#define NVME_MINORS		(1U << MINORBITS)

unsigned int admin_timeout = 60;
module_param(admin_timeout, uint, 0644);
MODULE_PARM_DESC(admin_timeout, "timeout in seconds for admin commands");
EXPORT_SYMBOL_GPL(admin_timeout);

unsigned int nvme_io_timeout = 30;
module_param_named(io_timeout, nvme_io_timeout, uint, 0644);
MODULE_PARM_DESC(io_timeout, "timeout in seconds for I/O");
EXPORT_SYMBOL_GPL(nvme_io_timeout);

static unsigned char shutdown_timeout = 5;
module_param(shutdown_timeout, byte, 0644);
MODULE_PARM_DESC(shutdown_timeout, "timeout in seconds for controller shutdown");

static u8 nvme_max_retries = 5;
module_param_named(max_retries, nvme_max_retries, byte, 0644);
MODULE_PARM_DESC(max_retries, "max number of retries a command may have");

static unsigned long default_ps_max_latency_us = 100000;
module_param(default_ps_max_latency_us, ulong, 0644);
MODULE_PARM_DESC(default_ps_max_latency_us,
		 "max power saving latency for new devices; use PM QOS to change per device");

static bool force_apst;
module_param(force_apst, bool, 0644);
MODULE_PARM_DESC(force_apst, "allow APST for newly enumerated devices even if quirked off");

static bool streams;
module_param(streams, bool, 0644);
MODULE_PARM_DESC(streams, "turn on support for Streams write directives");

/*
 * nvme_wq - hosts nvme related works that are not reset or delete
 * nvme_reset_wq - hosts nvme reset works
 * nvme_delete_wq - hosts nvme delete works
 *
 * nvme_wq will host works such are scan, aen handling, fw activation,
 * keep-alive error recovery, periodic reconnects etc. nvme_reset_wq
 * runs reset works which also flush works hosted on nvme_wq for
 * serialization purposes. nvme_delete_wq host controller deletion
 * works which flush reset works for serialization.
 */
struct workqueue_struct *nvme_wq;
EXPORT_SYMBOL_GPL(nvme_wq);

struct workqueue_struct *nvme_reset_wq;
EXPORT_SYMBOL_GPL(nvme_reset_wq);

struct workqueue_struct *nvme_delete_wq;
EXPORT_SYMBOL_GPL(nvme_delete_wq);

static DEFINE_IDA(nvme_subsystems_ida);
static LIST_HEAD(nvme_subsystems);
static DEFINE_MUTEX(nvme_subsystems_lock);

static DEFINE_IDA(nvme_instance_ida);
static dev_t nvme_chr_devt;
static struct class *nvme_class;
static struct class *nvme_subsys_class;

static void nvme_ns_remove(struct nvme_ns *ns);
static int nvme_revalidate_disk(struct gendisk *disk);

static __le32 nvme_get_log_dw10(u8 lid, size_t size)
{
	return cpu_to_le32((((size / 4) - 1) << 16) | lid);
}

int nvme_reset_ctrl(struct nvme_ctrl *ctrl)
{
	if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING))
		return -EBUSY;
	if (!queue_work(nvme_reset_wq, &ctrl->reset_work))
		return -EBUSY;
	return 0;
}
EXPORT_SYMBOL_GPL(nvme_reset_ctrl);

int nvme_reset_ctrl_sync(struct nvme_ctrl *ctrl)
{
	int ret;

	ret = nvme_reset_ctrl(ctrl);
	if (!ret)
		flush_work(&ctrl->reset_work);
	return ret;
}
EXPORT_SYMBOL_GPL(nvme_reset_ctrl_sync);

static void nvme_delete_ctrl_work(struct work_struct *work)
{
	struct nvme_ctrl *ctrl =
		container_of(work, struct nvme_ctrl, delete_work);

	flush_work(&ctrl->reset_work);
	nvme_stop_ctrl(ctrl);
	nvme_remove_namespaces(ctrl);
	ctrl->ops->delete_ctrl(ctrl);
	nvme_uninit_ctrl(ctrl);
	nvme_put_ctrl(ctrl);
}

int nvme_delete_ctrl(struct nvme_ctrl *ctrl)
{
	if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_DELETING))
		return -EBUSY;
	if (!queue_work(nvme_delete_wq, &ctrl->delete_work))
		return -EBUSY;
	return 0;
}
EXPORT_SYMBOL_GPL(nvme_delete_ctrl);

int nvme_delete_ctrl_sync(struct nvme_ctrl *ctrl)
{
	int ret = 0;

	/*
	 * Keep a reference until the work is flushed since ->delete_ctrl
	 * can free the controller.
	 */
	nvme_get_ctrl(ctrl);
	ret = nvme_delete_ctrl(ctrl);
	if (!ret)
		flush_work(&ctrl->delete_work);
	nvme_put_ctrl(ctrl);
	return ret;
}
EXPORT_SYMBOL_GPL(nvme_delete_ctrl_sync);

static inline bool nvme_ns_has_pi(struct nvme_ns *ns)
{
	return ns->pi_type && ns->ms == sizeof(struct t10_pi_tuple);
}

static blk_status_t nvme_error_status(struct request *req)
{
	switch (nvme_req(req)->status & 0x7ff) {
	case NVME_SC_SUCCESS:
		return BLK_STS_OK;
	case NVME_SC_CAP_EXCEEDED:
		return BLK_STS_NOSPC;
	case NVME_SC_LBA_RANGE:
		return BLK_STS_TARGET;
	case NVME_SC_BAD_ATTRIBUTES:
	case NVME_SC_ONCS_NOT_SUPPORTED:
	case NVME_SC_INVALID_OPCODE:
	case NVME_SC_INVALID_FIELD:
	case NVME_SC_INVALID_NS:
		return BLK_STS_NOTSUPP;
	case NVME_SC_WRITE_FAULT:
	case NVME_SC_READ_ERROR:
	case NVME_SC_UNWRITTEN_BLOCK:
	case NVME_SC_ACCESS_DENIED:
	case NVME_SC_READ_ONLY:
	case NVME_SC_COMPARE_FAILED:
		return BLK_STS_MEDIUM;
	case NVME_SC_GUARD_CHECK:
	case NVME_SC_APPTAG_CHECK:
	case NVME_SC_REFTAG_CHECK:
	case NVME_SC_INVALID_PI:
		return BLK_STS_PROTECTION;
	case NVME_SC_RESERVATION_CONFLICT:
		return BLK_STS_NEXUS;
	default:
		return BLK_STS_IOERR;
	}
}

static inline bool nvme_req_needs_retry(struct request *req)
{
	if (blk_noretry_request(req))
		return false;
	if (nvme_req(req)->status & NVME_SC_DNR)
		return false;
	if (nvme_req(req)->retries >= nvme_max_retries)
		return false;
	return true;
}

void nvme_complete_rq(struct request *req)
{
	blk_status_t status = nvme_error_status(req);

	trace_nvme_complete_rq(req);

	if (unlikely(status != BLK_STS_OK && nvme_req_needs_retry(req))) {
		if (nvme_req_needs_failover(req, status)) {
			nvme_failover_req(req);
			return;
		}

		if (!blk_queue_dying(req->q)) {
			nvme_req(req)->retries++;
			blk_mq_requeue_request(req, true);
			return;
		}
	}
	blk_mq_end_request(req, status);
}
EXPORT_SYMBOL_GPL(nvme_complete_rq);

void nvme_cancel_request(struct request *req, void *data, bool reserved)
{
	if (!blk_mq_request_started(req))
		return;

	dev_dbg_ratelimited(((struct nvme_ctrl *) data)->device,
				"Cancelling I/O %d", req->tag);

	nvme_req(req)->status = NVME_SC_ABORT_REQ;
	blk_mq_complete_request(req);

}
EXPORT_SYMBOL_GPL(nvme_cancel_request);

bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
		enum nvme_ctrl_state new_state)
{
	enum nvme_ctrl_state old_state;
	unsigned long flags;
	bool changed = false;

	spin_lock_irqsave(&ctrl->lock, flags);

	old_state = ctrl->state;
	switch (new_state) {
	case NVME_CTRL_ADMIN_ONLY:
		switch (old_state) {
		case NVME_CTRL_RECONNECTING:
			changed = true;
			/* FALLTHRU */
		default:
			break;
		}
		break;
	case NVME_CTRL_LIVE:
		switch (old_state) {
		case NVME_CTRL_NEW:
		case NVME_CTRL_RESETTING:
		case NVME_CTRL_RECONNECTING:
			changed = true;
			/* FALLTHRU */
		default:
			break;
		}
		break;
	case NVME_CTRL_RESETTING:
		switch (old_state) {
		case NVME_CTRL_NEW:
		case NVME_CTRL_LIVE:
		case NVME_CTRL_ADMIN_ONLY:
			changed = true;
			/* FALLTHRU */
		default:
			break;
		}
		break;
	case NVME_CTRL_RECONNECTING:
		switch (old_state) {
		case NVME_CTRL_LIVE:
		case NVME_CTRL_RESETTING:
			changed = true;
			/* FALLTHRU */
		default:
			break;
		}
		break;
	case NVME_CTRL_DELETING:
		switch (old_state) {
		case NVME_CTRL_LIVE:
		case NVME_CTRL_ADMIN_ONLY:
		case NVME_CTRL_RESETTING:
		case NVME_CTRL_RECONNECTING:
			changed = true;
			/* FALLTHRU */
		default:
			break;
		}
		break;
	case NVME_CTRL_DEAD:
		switch (old_state) {
		case NVME_CTRL_DELETING:
			changed = true;
			/* FALLTHRU */
		default:
			break;
		}
		break;
	default:
		break;
	}

	if (changed)
		ctrl->state = new_state;

	spin_unlock_irqrestore(&ctrl->lock, flags);
	if (changed && ctrl->state == NVME_CTRL_LIVE)
		nvme_kick_requeue_lists(ctrl);
	return changed;
}
EXPORT_SYMBOL_GPL(nvme_change_ctrl_state);

static void nvme_free_ns_head(struct kref *ref)
{
	struct nvme_ns_head *head =
		container_of(ref, struct nvme_ns_head, ref);

	nvme_mpath_remove_disk(head);
	ida_simple_remove(&head->subsys->ns_ida, head->instance);
	list_del_init(&head->entry);
	cleanup_srcu_struct(&head->srcu);
	kfree(head);
}

static void nvme_put_ns_head(struct nvme_ns_head *head)
{
	kref_put(&head->ref, nvme_free_ns_head);
}

static void nvme_free_ns(struct kref *kref)
{
	struct nvme_ns *ns = container_of(kref, struct nvme_ns, kref);

	if (ns->ndev)
		nvme_nvm_unregister(ns);

	put_disk(ns->disk);
	nvme_put_ns_head(ns->head);
	nvme_put_ctrl(ns->ctrl);
	kfree(ns);
}

static void nvme_put_ns(struct nvme_ns *ns)
{
	kref_put(&ns->kref, nvme_free_ns);
}

struct request *nvme_alloc_request(struct request_queue *q,
		struct nvme_command *cmd, blk_mq_req_flags_t flags, int qid)
{
	unsigned op = nvme_is_write(cmd) ? REQ_OP_DRV_OUT : REQ_OP_DRV_IN;
	struct request *req;

	if (qid == NVME_QID_ANY) {
		req = blk_mq_alloc_request(q, op, flags);
	} else {
		req = blk_mq_alloc_request_hctx(q, op, flags,
				qid ? qid - 1 : 0);
	}
	if (IS_ERR(req))
		return req;

	req->cmd_flags |= REQ_FAILFAST_DRIVER;
	nvme_req(req)->cmd = cmd;

	return req;
}
EXPORT_SYMBOL_GPL(nvme_alloc_request);

static int nvme_toggle_streams(struct nvme_ctrl *ctrl, bool enable)
{
	struct nvme_command c;

	memset(&c, 0, sizeof(c));

	c.directive.opcode = nvme_admin_directive_send;
	c.directive.nsid = cpu_to_le32(NVME_NSID_ALL);
	c.directive.doper = NVME_DIR_SND_ID_OP_ENABLE;
	c.directive.dtype = NVME_DIR_IDENTIFY;
	c.directive.tdtype = NVME_DIR_STREAMS;
	c.directive.endir = enable ? NVME_DIR_ENDIR : 0;

	return nvme_submit_sync_cmd(ctrl->admin_q, &c, NULL, 0);
}

static int nvme_disable_streams(struct nvme_ctrl *ctrl)
{
	return nvme_toggle_streams(ctrl, false);
}

static int nvme_enable_streams(struct nvme_ctrl *ctrl)
{
	return nvme_toggle_streams(ctrl, true);
}

static int nvme_get_stream_params(struct nvme_ctrl *ctrl,
				  struct streams_directive_params *s, u32 nsid)
{
	struct nvme_command c;

	memset(&c, 0, sizeof(c));
	memset(s, 0, sizeof(*s));

	c.directive.opcode = nvme_admin_directive_recv;
	c.directive.nsid = cpu_to_le32(nsid);
	c.directive.numd = cpu_to_le32((sizeof(*s) >> 2) - 1);
	c.directive.doper = NVME_DIR_RCV_ST_OP_PARAM;
	c.directive.dtype = NVME_DIR_STREAMS;

	return nvme_submit_sync_cmd(ctrl->admin_q, &c, s, sizeof(*s));
}

static int nvme_configure_directives(struct nvme_ctrl *ctrl)
{
	struct streams_directive_params s;
	int ret;

	if (!(ctrl->oacs & NVME_CTRL_OACS_DIRECTIVES))
		return 0;
	if (!streams)
		return 0;

	ret = nvme_enable_streams(ctrl);
	if (ret)
		return ret;

	ret = nvme_get_stream_params(ctrl, &s, NVME_NSID_ALL);
	if (ret)
		return ret;

	ctrl->nssa = le16_to_cpu(s.nssa);
	if (ctrl->nssa < BLK_MAX_WRITE_HINTS - 1) {
		dev_info(ctrl->device, "too few streams (%u) available\n",
					ctrl->nssa);
		nvme_disable_streams(ctrl);
		return 0;
	}

	ctrl->nr_streams = min_t(unsigned, ctrl->nssa, BLK_MAX_WRITE_HINTS - 1);
	dev_info(ctrl->device, "Using %u streams\n", ctrl->nr_streams);
	return 0;
}

/*
 * Check if 'req' has a write hint associated with it. If it does, assign
 * a valid namespace stream to the write.
 */
static void nvme_assign_write_stream(struct nvme_ctrl *ctrl,
				     struct request *req, u16 *control,
				     u32 *dsmgmt)
{
	enum rw_hint streamid = req->write_hint;

	if (streamid == WRITE_LIFE_NOT_SET || streamid == WRITE_LIFE_NONE)
		streamid = 0;
	else {
		streamid--;
		if (WARN_ON_ONCE(streamid > ctrl->nr_streams))
			return;

		*control |= NVME_RW_DTYPE_STREAMS;
		*dsmgmt |= streamid << 16;
	}

	if (streamid < ARRAY_SIZE(req->q->write_hints))
		req->q->write_hints[streamid] += blk_rq_bytes(req) >> 9;
}

static inline void nvme_setup_flush(struct nvme_ns *ns,
		struct nvme_command *cmnd)
{
	memset(cmnd, 0, sizeof(*cmnd));
	cmnd->common.opcode = nvme_cmd_flush;
	cmnd->common.nsid = cpu_to_le32(ns->head->ns_id);
}

static blk_status_t nvme_setup_discard(struct nvme_ns *ns, struct request *req,
		struct nvme_command *cmnd)
{
	unsigned short segments = blk_rq_nr_discard_segments(req), n = 0;
	struct nvme_dsm_range *range;
	struct bio *bio;

	range = kmalloc_array(segments, sizeof(*range), GFP_ATOMIC);
	if (!range)
		return BLK_STS_RESOURCE;

	__rq_for_each_bio(bio, req) {
		u64 slba = nvme_block_nr(ns, bio->bi_iter.bi_sector);
		u32 nlb = bio->bi_iter.bi_size >> ns->lba_shift;

		range[n].cattr = cpu_to_le32(0);
		range[n].nlb = cpu_to_le32(nlb);
		range[n].slba = cpu_to_le64(slba);
		n++;
	}

	if (WARN_ON_ONCE(n != segments)) {
		kfree(range);
		return BLK_STS_IOERR;
	}

	memset(cmnd, 0, sizeof(*cmnd));
	cmnd->dsm.opcode = nvme_cmd_dsm;
	cmnd->dsm.nsid = cpu_to_le32(ns->head->ns_id);
	cmnd->dsm.nr = cpu_to_le32(segments - 1);
	cmnd->dsm.attributes = cpu_to_le32(NVME_DSMGMT_AD);

	req->special_vec.bv_page = virt_to_page(range);
	req->special_vec.bv_offset = offset_in_page(range);
	req->special_vec.bv_len = sizeof(*range) * segments;
	req->rq_flags |= RQF_SPECIAL_PAYLOAD;

	return BLK_STS_OK;
}

static inline blk_status_t nvme_setup_rw(struct nvme_ns *ns,
		struct request *req, struct nvme_command *cmnd)
{
	struct nvme_ctrl *ctrl = ns->ctrl;
	u16 control = 0;
	u32 dsmgmt = 0;

	if (req->cmd_flags & REQ_FUA)
		control |= NVME_RW_FUA;
	if (req->cmd_flags & (REQ_FAILFAST_DEV | REQ_RAHEAD))
		control |= NVME_RW_LR;

	if (req->cmd_flags & REQ_RAHEAD)
		dsmgmt |= NVME_RW_DSM_FREQ_PREFETCH;

	memset(cmnd, 0, sizeof(*cmnd));
	cmnd->rw.opcode = (rq_data_dir(req) ? nvme_cmd_write : nvme_cmd_read);
	cmnd->rw.nsid = cpu_to_le32(ns->head->ns_id);
	cmnd->rw.slba = cpu_to_le64(nvme_block_nr(ns, blk_rq_pos(req)));
	cmnd->rw.length = cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);

	if (req_op(req) == REQ_OP_WRITE && ctrl->nr_streams)
		nvme_assign_write_stream(ctrl, req, &control, &dsmgmt);

	if (ns->ms) {
		/*
		 * If formated with metadata, the block layer always provides a
		 * metadata buffer if CONFIG_BLK_DEV_INTEGRITY is enabled.  Else
		 * we enable the PRACT bit for protection information or set the
		 * namespace capacity to zero to prevent any I/O.
		 */
		if (!blk_integrity_rq(req)) {
			if (WARN_ON_ONCE(!nvme_ns_has_pi(ns)))
				return BLK_STS_NOTSUPP;
			control |= NVME_RW_PRINFO_PRACT;
		}

		switch (ns->pi_type) {
		case NVME_NS_DPS_PI_TYPE3:
			control |= NVME_RW_PRINFO_PRCHK_GUARD;
			break;
		case NVME_NS_DPS_PI_TYPE1:
		case NVME_NS_DPS_PI_TYPE2:
			control |= NVME_RW_PRINFO_PRCHK_GUARD |
					NVME_RW_PRINFO_PRCHK_REF;
			cmnd->rw.reftag = cpu_to_le32(
					nvme_block_nr(ns, blk_rq_pos(req)));
			break;
		}
	}

	cmnd->rw.control = cpu_to_le16(control);
	cmnd->rw.dsmgmt = cpu_to_le32(dsmgmt);
	return 0;
}

blk_status_t nvme_setup_cmd(struct nvme_ns *ns, struct request *req,
		struct nvme_command *cmd)
{
	blk_status_t ret = BLK_STS_OK;

	if (!(req->rq_flags & RQF_DONTPREP)) {
		nvme_req(req)->retries = 0;
		nvme_req(req)->flags = 0;
		req->rq_flags |= RQF_DONTPREP;
	}

	switch (req_op(req)) {
	case REQ_OP_DRV_IN:
	case REQ_OP_DRV_OUT:
		memcpy(cmd, nvme_req(req)->cmd, sizeof(*cmd));
		break;
	case REQ_OP_FLUSH:
		nvme_setup_flush(ns, cmd);
		break;
	case REQ_OP_WRITE_ZEROES:
		/* currently only aliased to deallocate for a few ctrls: */
	case REQ_OP_DISCARD:
		ret = nvme_setup_discard(ns, req, cmd);
		break;
	case REQ_OP_READ:
	case REQ_OP_WRITE:
		ret = nvme_setup_rw(ns, req, cmd);
		break;
	default:
		WARN_ON_ONCE(1);
		return BLK_STS_IOERR;
	}

	cmd->common.command_id = req->tag;
	if (ns)
		trace_nvme_setup_nvm_cmd(req->q->id, cmd);
	else
		trace_nvme_setup_admin_cmd(cmd);
	return ret;
}
EXPORT_SYMBOL_GPL(nvme_setup_cmd);

/*
 * Returns 0 on success.  If the result is negative, it's a Linux error code;
 * if the result is positive, it's an NVM Express status code
 */
int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
		union nvme_result *result, void *buffer, unsigned bufflen,
		unsigned timeout, int qid, int at_head,
		blk_mq_req_flags_t flags)
{
	struct request *req;
	int ret;

	req = nvme_alloc_request(q, cmd, flags, qid);
	if (IS_ERR(req))
		return PTR_ERR(req);

	req->timeout = timeout ? timeout : ADMIN_TIMEOUT;

	if (buffer && bufflen) {
		ret = blk_rq_map_kern(q, req, buffer, bufflen, GFP_KERNEL);
		if (ret)
			goto out;
	}

	blk_execute_rq(req->q, NULL, req, at_head);
	if (result)
		*result = nvme_req(req)->result;
	if (nvme_req(req)->flags & NVME_REQ_CANCELLED)
		ret = -EINTR;
	else
		ret = nvme_req(req)->status;
 out:
	blk_mq_free_request(req);
	return ret;
}
EXPORT_SYMBOL_GPL(__nvme_submit_sync_cmd);

int nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
		void *buffer, unsigned bufflen)
{
	return __nvme_submit_sync_cmd(q, cmd, NULL, buffer, bufflen, 0,
			NVME_QID_ANY, 0, 0);
}
EXPORT_SYMBOL_GPL(nvme_submit_sync_cmd);

static void *nvme_add_user_metadata(struct bio *bio, void __user *ubuf,
		unsigned len, u32 seed, bool write)
{
	struct bio_integrity_payload *bip;
	int ret = -ENOMEM;
	void *buf;

	buf = kmalloc(len, GFP_KERNEL);
	if (!buf)
		goto out;

	ret = -EFAULT;
	if (write && copy_from_user(buf, ubuf, len))
		goto out_free_meta;

	bip = bio_integrity_alloc(bio, GFP_KERNEL, 1);
	if (IS_ERR(bip)) {
		ret = PTR_ERR(bip);
		goto out_free_meta;
	}

	bip->bip_iter.bi_size = len;
	bip->bip_iter.bi_sector = seed;
	ret = bio_integrity_add_page(bio, virt_to_page(buf), len,
			offset_in_page(buf));
	if (ret == len)
		return buf;
	ret = -ENOMEM;
out_free_meta:
	kfree(buf);
out:
	return ERR_PTR(ret);
}

static int nvme_submit_user_cmd(struct request_queue *q,
		struct nvme_command *cmd, void __user *ubuffer,
		unsigned bufflen, void __user *meta_buffer, unsigned meta_len,
		u32 meta_seed, u32 *result, unsigned timeout)
{
	bool write = nvme_is_write(cmd);
	struct nvme_ns *ns = q->queuedata;
	struct gendisk *disk = ns ? ns->disk : NULL;
	struct request *req;
	struct bio *bio = NULL;
	void *meta = NULL;
	int ret;

	req = nvme_alloc_request(q, cmd, 0, NVME_QID_ANY);
	if (IS_ERR(req))
		return PTR_ERR(req);

	req->timeout = timeout ? timeout : ADMIN_TIMEOUT;

	if (ubuffer && bufflen) {
		ret = blk_rq_map_user(q, req, NULL, ubuffer, bufflen,
				GFP_KERNEL);
		if (ret)
			goto out;
		bio = req->bio;
		bio->bi_disk = disk;
		if (disk && meta_buffer && meta_len) {
			meta = nvme_add_user_metadata(bio, meta_buffer, meta_len,
					meta_seed, write);
			if (IS_ERR(meta)) {
				ret = PTR_ERR(meta);
				goto out_unmap;
			}
		}
	}

	blk_execute_rq(req->q, disk, req, 0);
	if (nvme_req(req)->flags & NVME_REQ_CANCELLED)
		ret = -EINTR;
	else
		ret = nvme_req(req)->status;
	if (result)
		*result = le32_to_cpu(nvme_req(req)->result.u32);
	if (meta && !ret && !write) {
		if (copy_to_user(meta_buffer, meta, meta_len))
			ret = -EFAULT;
	}
	kfree(meta);
 out_unmap:
	if (bio)
		blk_rq_unmap_user(bio);
 out:
	blk_mq_free_request(req);
	return ret;
}

static void nvme_keep_alive_end_io(struct request *rq, blk_status_t status)
{
	struct nvme_ctrl *ctrl = rq->end_io_data;

	blk_mq_free_request(rq);

	if (status) {
		dev_err(ctrl->device,
			"failed nvme_keep_alive_end_io error=%d\n",
				status);
		return;
	}

	schedule_delayed_work(&ctrl->ka_work, ctrl->kato * HZ);
}

static int nvme_keep_alive(struct nvme_ctrl *ctrl)
{
	struct nvme_command c;
	struct request *rq;

	memset(&c, 0, sizeof(c));
	c.common.opcode = nvme_admin_keep_alive;

	rq = nvme_alloc_request(ctrl->admin_q, &c, BLK_MQ_REQ_RESERVED,
			NVME_QID_ANY);
	if (IS_ERR(rq))
		return PTR_ERR(rq);

	rq->timeout = ctrl->kato * HZ;
	rq->end_io_data = ctrl;

	blk_execute_rq_nowait(rq->q, NULL, rq, 0, nvme_keep_alive_end_io);

	return 0;
}

static void nvme_keep_alive_work(struct work_struct *work)
{
	struct nvme_ctrl *ctrl = container_of(to_delayed_work(work),
			struct nvme_ctrl, ka_work);

	if (nvme_keep_alive(ctrl)) {
		/* allocation failure, reset the controller */
		dev_err(ctrl->device, "keep-alive failed\n");
		nvme_reset_ctrl(ctrl);
		return;
	}
}

void nvme_start_keep_alive(struct nvme_ctrl *ctrl)
{
	if (unlikely(ctrl->kato == 0))
		return;

	INIT_DELAYED_WORK(&ctrl->ka_work, nvme_keep_alive_work);
	schedule_delayed_work(&ctrl->ka_work, ctrl->kato * HZ);
}
EXPORT_SYMBOL_GPL(nvme_start_keep_alive);

void nvme_stop_keep_alive(struct nvme_ctrl *ctrl)
{
	if (unlikely(ctrl->kato == 0))
		return;

	cancel_delayed_work_sync(&ctrl->ka_work);
}
EXPORT_SYMBOL_GPL(nvme_stop_keep_alive);

static int nvme_identify_ctrl(struct nvme_ctrl *dev, struct nvme_id_ctrl **id)
{
	struct nvme_command c = { };
	int error;

	/* gcc-4.4.4 (at least) has issues with initializers and anon unions */
	c.identify.opcode = nvme_admin_identify;
	c.identify.cns = NVME_ID_CNS_CTRL;

	*id = kmalloc(sizeof(struct nvme_id_ctrl), GFP_KERNEL);
	if (!*id)
		return -ENOMEM;

	error = nvme_submit_sync_cmd(dev->admin_q, &c, *id,
			sizeof(struct nvme_id_ctrl));
	if (error)
		kfree(*id);
	return error;
}

static int nvme_identify_ns_descs(struct nvme_ctrl *ctrl, unsigned nsid,
		struct nvme_ns_ids *ids)
{
	struct nvme_command c = { };
	int status;
	void *data;
	int pos;
	int len;

	c.identify.opcode = nvme_admin_identify;
	c.identify.nsid = cpu_to_le32(nsid);
	c.identify.cns = NVME_ID_CNS_NS_DESC_LIST;

	data = kzalloc(NVME_IDENTIFY_DATA_SIZE, GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	status = nvme_submit_sync_cmd(ctrl->admin_q, &c, data,
				      NVME_IDENTIFY_DATA_SIZE);
	if (status)
		goto free_data;

	for (pos = 0; pos < NVME_IDENTIFY_DATA_SIZE; pos += len) {
		struct nvme_ns_id_desc *cur = data + pos;

		if (cur->nidl == 0)
			break;

		switch (cur->nidt) {
		case NVME_NIDT_EUI64:
			if (cur->nidl != NVME_NIDT_EUI64_LEN) {
				dev_warn(ctrl->device,
					 "ctrl returned bogus length: %d for NVME_NIDT_EUI64\n",
					 cur->nidl);
				goto free_data;
			}
			len = NVME_NIDT_EUI64_LEN;
			memcpy(ids->eui64, data + pos + sizeof(*cur), len);
			break;
		case NVME_NIDT_NGUID:
			if (cur->nidl != NVME_NIDT_NGUID_LEN) {
				dev_warn(ctrl->device,
					 "ctrl returned bogus length: %d for NVME_NIDT_NGUID\n",
					 cur->nidl);
				goto free_data;
			}
			len = NVME_NIDT_NGUID_LEN;
			memcpy(ids->nguid, data + pos + sizeof(*cur), len);
			break;
		case NVME_NIDT_UUID:
			if (cur->nidl != NVME_NIDT_UUID_LEN) {
				dev_warn(ctrl->device,
					 "ctrl returned bogus length: %d for NVME_NIDT_UUID\n",
					 cur->nidl);
				goto free_data;
			}
			len = NVME_NIDT_UUID_LEN;
			uuid_copy(&ids->uuid, data + pos + sizeof(*cur));
			break;
		default:
			/* Skip unnkown types */
			len = cur->nidl;
			break;
		}

		len += sizeof(*cur);
	}
free_data:
	kfree(data);
	return status;
}

static int nvme_identify_ns_list(struct nvme_ctrl *dev, unsigned nsid, __le32 *ns_list)
{
	struct nvme_command c = { };

	c.identify.opcode = nvme_admin_identify;
	c.identify.cns = NVME_ID_CNS_NS_ACTIVE_LIST;
	c.identify.nsid = cpu_to_le32(nsid);
	return nvme_submit_sync_cmd(dev->admin_q, &c, ns_list, 0x1000);
}

static struct nvme_id_ns *nvme_identify_ns(struct nvme_ctrl *ctrl,
		unsigned nsid)
{
	struct nvme_id_ns *id;
	struct nvme_command c = { };
	int error;

	/* gcc-4.4.4 (at least) has issues with initializers and anon unions */
	c.identify.opcode = nvme_admin_identify;
	c.identify.nsid = cpu_to_le32(nsid);
	c.identify.cns = NVME_ID_CNS_NS;

	id = kmalloc(sizeof(*id), GFP_KERNEL);
	if (!id)
		return NULL;

	error = nvme_submit_sync_cmd(ctrl->admin_q, &c, id, sizeof(*id));
	if (error) {
		dev_warn(ctrl->device, "Identify namespace failed\n");
		kfree(id);
		return NULL;
	}

	return id;
}

static int nvme_set_features(struct nvme_ctrl *dev, unsigned fid, unsigned dword11,
		      void *buffer, size_t buflen, u32 *result)
{
	struct nvme_command c;
	union nvme_result res;
	int ret;

	memset(&c, 0, sizeof(c));
	c.features.opcode = nvme_admin_set_features;
	c.features.fid = cpu_to_le32(fid);
	c.features.dword11 = cpu_to_le32(dword11);

	ret = __nvme_submit_sync_cmd(dev->admin_q, &c, &res,
			buffer, buflen, 0, NVME_QID_ANY, 0, 0);
	if (ret >= 0 && result)
		*result = le32_to_cpu(res.u32);
	return ret;
}

int nvme_set_queue_count(struct nvme_ctrl *ctrl, int *count)
{
	u32 q_count = (*count - 1) | ((*count - 1) << 16);
	u32 result;
	int status, nr_io_queues;

	status = nvme_set_features(ctrl, NVME_FEAT_NUM_QUEUES, q_count, NULL, 0,
			&result);
	if (status < 0)
		return status;

	/*
	 * Degraded controllers might return an error when setting the queue
	 * count.  We still want to be able to bring them online and offer
	 * access to the admin queue, as that might be only way to fix them up.
	 */
	if (status > 0) {
		dev_err(ctrl->device, "Could not set queue count (%d)\n", status);
		*count = 0;
	} else {
		nr_io_queues = min(result & 0xffff, result >> 16) + 1;
		*count = min(*count, nr_io_queues);
	}

	return 0;
}
EXPORT_SYMBOL_GPL(nvme_set_queue_count);

static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
{
	struct nvme_user_io io;
	struct nvme_command c;
	unsigned length, meta_len;
	void __user *metadata;

	if (copy_from_user(&io, uio, sizeof(io)))
		return -EFAULT;
	if (io.flags)
		return -EINVAL;

	switch (io.opcode) {
	case nvme_cmd_write:
	case nvme_cmd_read:
	case nvme_cmd_compare:
		break;
	default:
		return -EINVAL;
	}

	length = (io.nblocks + 1) << ns->lba_shift;
	meta_len = (io.nblocks + 1) * ns->ms;
	metadata = (void __user *)(uintptr_t)io.metadata;

	if (ns->ext) {
		length += meta_len;
		meta_len = 0;
	} else if (meta_len) {
		if ((io.metadata & 3) || !io.metadata)
			return -EINVAL;
	}

	memset(&c, 0, sizeof(c));
	c.rw.opcode = io.opcode;
	c.rw.flags = io.flags;
	c.rw.nsid = cpu_to_le32(ns->head->ns_id);
	c.rw.slba = cpu_to_le64(io.slba);
	c.rw.length = cpu_to_le16(io.nblocks);
	c.rw.control = cpu_to_le16(io.control);
	c.rw.dsmgmt = cpu_to_le32(io.dsmgmt);
	c.rw.reftag = cpu_to_le32(io.reftag);
	c.rw.apptag = cpu_to_le16(io.apptag);
	c.rw.appmask = cpu_to_le16(io.appmask);

	return nvme_submit_user_cmd(ns->queue, &c,
			(void __user *)(uintptr_t)io.addr, length,
			metadata, meta_len, io.slba, NULL, 0);
}

static u32 nvme_known_admin_effects(u8 opcode)
{
	switch (opcode) {
	case nvme_admin_format_nvm:
		return NVME_CMD_EFFECTS_CSUPP | NVME_CMD_EFFECTS_LBCC |
					NVME_CMD_EFFECTS_CSE_MASK;
	case nvme_admin_sanitize_nvm:
		return NVME_CMD_EFFECTS_CSE_MASK;
	default:
		break;
	}
	return 0;
}

static u32 nvme_passthru_start(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
								u8 opcode)
{
	u32 effects = 0;

	if (ns) {
		if (ctrl->effects)
			effects = le32_to_cpu(ctrl->effects->iocs[opcode]);
		if (effects & ~NVME_CMD_EFFECTS_CSUPP)
			dev_warn(ctrl->device,
				 "IO command:%02x has unhandled effects:%08x\n",
				 opcode, effects);
		return 0;
	}

	if (ctrl->effects)
		effects = le32_to_cpu(ctrl->effects->iocs[opcode]);
	else
		effects = nvme_known_admin_effects(opcode);

	/*
	 * For simplicity, IO to all namespaces is quiesced even if the command
	 * effects say only one namespace is affected.
	 */
	if (effects & (NVME_CMD_EFFECTS_LBCC | NVME_CMD_EFFECTS_CSE_MASK)) {
		nvme_start_freeze(ctrl);
		nvme_wait_freeze(ctrl);
	}
	return effects;
}

static void nvme_update_formats(struct nvme_ctrl *ctrl)
{
	struct nvme_ns *ns;

	mutex_lock(&ctrl->namespaces_mutex);
	list_for_each_entry(ns, &ctrl->namespaces, list) {
		if (ns->disk && nvme_revalidate_disk(ns->disk))
			nvme_ns_remove(ns);
	}
	mutex_unlock(&ctrl->namespaces_mutex);
}

static void nvme_passthru_end(struct nvme_ctrl *ctrl, u32 effects)
{
	/*
	 * Revalidate LBA changes prior to unfreezing. This is necessary to
	 * prevent memory corruption if a logical block size was changed by
	 * this command.
	 */
	if (effects & NVME_CMD_EFFECTS_LBCC)
		nvme_update_formats(ctrl);
	if (effects & (NVME_CMD_EFFECTS_LBCC | NVME_CMD_EFFECTS_CSE_MASK))
		nvme_unfreeze(ctrl);
	if (effects & NVME_CMD_EFFECTS_CCC)
		nvme_init_identify(ctrl);
	if (effects & (NVME_CMD_EFFECTS_NIC | NVME_CMD_EFFECTS_NCC))
		nvme_queue_scan(ctrl);
}

static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
			struct nvme_passthru_cmd __user *ucmd)
{
	struct nvme_passthru_cmd cmd;
	struct nvme_command c;
	unsigned timeout = 0;
	u32 effects;
	int status;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;
	if (copy_from_user(&cmd, ucmd, sizeof(cmd)))
		return -EFAULT;
	if (cmd.flags)
		return -EINVAL;

	memset(&c, 0, sizeof(c));
	c.common.opcode = cmd.opcode;
	c.common.flags = cmd.flags;
	c.common.nsid = cpu_to_le32(cmd.nsid);
	c.common.cdw2[0] = cpu_to_le32(cmd.cdw2);
	c.common.cdw2[1] = cpu_to_le32(cmd.cdw3);
	c.common.cdw10[0] = cpu_to_le32(cmd.cdw10);
	c.common.cdw10[1] = cpu_to_le32(cmd.cdw11);
	c.common.cdw10[2] = cpu_to_le32(cmd.cdw12);
	c.common.cdw10[3] = cpu_to_le32(cmd.cdw13);
	c.common.cdw10[4] = cpu_to_le32(cmd.cdw14);
	c.common.cdw10[5] = cpu_to_le32(cmd.cdw15);

	if (cmd.timeout_ms)
		timeout = msecs_to_jiffies(cmd.timeout_ms);

	effects = nvme_passthru_start(ctrl, ns, cmd.opcode);
	status = nvme_submit_user_cmd(ns ? ns->queue : ctrl->admin_q, &c,
			(void __user *)(uintptr_t)cmd.addr, cmd.data_len,
			(void __user *)(uintptr_t)cmd.metadata, cmd.metadata,
			0, &cmd.result, timeout);
	nvme_passthru_end(ctrl, effects);

	if (status >= 0) {
		if (put_user(cmd.result, &ucmd->result))
			return -EFAULT;
	}

	return status;
}

/*
 * Issue ioctl requests on the first available path.  Note that unlike normal
 * block layer requests we will not retry failed request on another controller.
 */
static struct nvme_ns *nvme_get_ns_from_disk(struct gendisk *disk,
		struct nvme_ns_head **head, int *srcu_idx)
{
#ifdef CONFIG_NVME_MULTIPATH
	if (disk->fops == &nvme_ns_head_ops) {
		*head = disk->private_data;
		*srcu_idx = srcu_read_lock(&(*head)->srcu);
		return nvme_find_path(*head);
	}
#endif
	*head = NULL;
	*srcu_idx = -1;
	return disk->private_data;
}

static void nvme_put_ns_from_disk(struct nvme_ns_head *head, int idx)
{
	if (head)
		srcu_read_unlock(&head->srcu, idx);
}

static int nvme_ns_ioctl(struct nvme_ns *ns, unsigned cmd, unsigned long arg)
{
	switch (cmd) {
	case NVME_IOCTL_ID:
		force_successful_syscall_return();
		return ns->head->ns_id;
	case NVME_IOCTL_ADMIN_CMD:
		return nvme_user_cmd(ns->ctrl, NULL, (void __user *)arg);
	case NVME_IOCTL_IO_CMD:
		return nvme_user_cmd(ns->ctrl, ns, (void __user *)arg);
	case NVME_IOCTL_SUBMIT_IO:
		return nvme_submit_io(ns, (void __user *)arg);
	default:
#ifdef CONFIG_NVM
		if (ns->ndev)
			return nvme_nvm_ioctl(ns, cmd, arg);
#endif
		if (is_sed_ioctl(cmd))
			return sed_ioctl(ns->ctrl->opal_dev, cmd,
					 (void __user *) arg);
		return -ENOTTY;
	}
}

static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
		unsigned int cmd, unsigned long arg)
{
	struct nvme_ns_head *head = NULL;
	struct nvme_ns *ns;
	int srcu_idx, ret;

	ns = nvme_get_ns_from_disk(bdev->bd_disk, &head, &srcu_idx);
	if (unlikely(!ns))
		ret = -EWOULDBLOCK;
	else
		ret = nvme_ns_ioctl(ns, cmd, arg);
	nvme_put_ns_from_disk(head, srcu_idx);
	return ret;
}

static int nvme_open(struct block_device *bdev, fmode_t mode)
{
	struct nvme_ns *ns = bdev->bd_disk->private_data;

#ifdef CONFIG_NVME_MULTIPATH
	/* should never be called due to GENHD_FL_HIDDEN */
	if (WARN_ON_ONCE(ns->head->disk))
		goto fail;
#endif
	if (!kref_get_unless_zero(&ns->kref))
		goto fail;
	if (!try_module_get(ns->ctrl->ops->module))
		goto fail_put_ns;

	return 0;

fail_put_ns:
	nvme_put_ns(ns);
fail:
	return -ENXIO;
}

static void nvme_release(struct gendisk *disk, fmode_t mode)
{
	struct nvme_ns *ns = disk->private_data;

	module_put(ns->ctrl->ops->module);
	nvme_put_ns(ns);
}

static int nvme_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
	/* some standard values */
	geo->heads = 1 << 6;
	geo->sectors = 1 << 5;
	geo->cylinders = get_capacity(bdev->bd_disk) >> 11;
	return 0;
}

#ifdef CONFIG_BLK_DEV_INTEGRITY
static void nvme_init_integrity(struct gendisk *disk, u16 ms, u8 pi_type)
{
	struct blk_integrity integrity;

	memset(&integrity, 0, sizeof(integrity));
	switch (pi_type) {
	case NVME_NS_DPS_PI_TYPE3:
		integrity.profile = &t10_pi_type3_crc;
		integrity.tag_size = sizeof(u16) + sizeof(u32);
		integrity.flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
		break;
	case NVME_NS_DPS_PI_TYPE1:
	case NVME_NS_DPS_PI_TYPE2:
		integrity.profile = &t10_pi_type1_crc;
		integrity.tag_size = sizeof(u16);
		integrity.flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
		break;
	default:
		integrity.profile = NULL;
		break;
	}
	integrity.tuple_size = ms;
	blk_integrity_register(disk, &integrity);
	blk_queue_max_integrity_segments(disk->queue, 1);
}
#else
static void nvme_init_integrity(struct gendisk *disk, u16 ms, u8 pi_type)
{
}
#endif /* CONFIG_BLK_DEV_INTEGRITY */

static void nvme_set_chunk_size(struct nvme_ns *ns)
{
	u32 chunk_size = (((u32)ns->noiob) << (ns->lba_shift - 9));
	blk_queue_chunk_sectors(ns->queue, rounddown_pow_of_two(chunk_size));
}

static void nvme_config_discard(struct nvme_ctrl *ctrl,
		unsigned stream_alignment, struct request_queue *queue)
{
	u32 size = queue_logical_block_size(queue);

	if (stream_alignment)
		size *= stream_alignment;

	BUILD_BUG_ON(PAGE_SIZE / sizeof(struct nvme_dsm_range) <
			NVME_DSM_MAX_RANGES);

	queue->limits.discard_alignment = 0;
	queue->limits.discard_granularity = size;

	blk_queue_max_discard_sectors(queue, UINT_MAX);
	blk_queue_max_discard_segments(queue, NVME_DSM_MAX_RANGES);
	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, queue);

	if (ctrl->quirks & NVME_QUIRK_DEALLOCATE_ZEROES)
		blk_queue_max_write_zeroes_sectors(queue, UINT_MAX);
}

static void nvme_report_ns_ids(struct nvme_ctrl *ctrl, unsigned int nsid,
		struct nvme_id_ns *id, struct nvme_ns_ids *ids)
{
	memset(ids, 0, sizeof(*ids));

	if (ctrl->vs >= NVME_VS(1, 1, 0))
		memcpy(ids->eui64, id->eui64, sizeof(id->eui64));
	if (ctrl->vs >= NVME_VS(1, 2, 0))
		memcpy(ids->nguid, id->nguid, sizeof(id->nguid));
	if (ctrl->vs >= NVME_VS(1, 3, 0)) {
		 /* Don't treat error as fatal we potentially
		  * already have a NGUID or EUI-64
		  */
		if (nvme_identify_ns_descs(ctrl, nsid, ids))
			dev_warn(ctrl->device,
				 "%s: Identify Descriptors failed\n", __func__);
	}
}

static bool nvme_ns_ids_valid(struct nvme_ns_ids *ids)
{
	return !uuid_is_null(&ids->uuid) ||
		memchr_inv(ids->nguid, 0, sizeof(ids->nguid)) ||
		memchr_inv(ids->eui64, 0, sizeof(ids->eui64));
}

static bool nvme_ns_ids_equal(struct nvme_ns_ids *a, struct nvme_ns_ids *b)
{
	return uuid_equal(&a->uuid, &b->uuid) &&
		memcmp(&a->nguid, &b->nguid, sizeof(a->nguid)) == 0 &&
		memcmp(&a->eui64, &b->eui64, sizeof(a->eui64)) == 0;
}

static void nvme_update_disk_info(struct gendisk *disk,
		struct nvme_ns *ns, struct nvme_id_ns *id)
{
	sector_t capacity = le64_to_cpup(&id->nsze) << (ns->lba_shift - 9);
	unsigned short bs = 1 << ns->lba_shift;
	unsigned stream_alignment = 0;

	if (ns->ctrl->nr_streams && ns->sws && ns->sgs)
		stream_alignment = ns->sws * ns->sgs;

	blk_mq_freeze_queue(disk->queue);
	blk_integrity_unregister(disk);

	blk_queue_logical_block_size(disk->queue, bs);
	blk_queue_physical_block_size(disk->queue, bs);
	blk_queue_io_min(disk->queue, bs);

	if (ns->ms && !ns->ext &&
	    (ns->ctrl->ops->flags & NVME_F_METADATA_SUPPORTED))
		nvme_init_integrity(disk, ns->ms, ns->pi_type);
	if (ns->ms && !nvme_ns_has_pi(ns) && !blk_get_integrity(disk))
		capacity = 0;
	set_capacity(disk, capacity);

	if (ns->ctrl->oncs & NVME_CTRL_ONCS_DSM)
		nvme_config_discard(ns->ctrl, stream_alignment, disk->queue);
	blk_mq_unfreeze_queue(disk->queue);
}

static void __nvme_revalidate_disk(struct gendisk *disk, struct nvme_id_ns *id)
{
	struct nvme_ns *ns = disk->private_data;

	/*
	 * If identify namespace failed, use default 512 byte block size so
	 * block layer can use before failing read/write for 0 capacity.
	 */
	ns->lba_shift = id->lbaf[id->flbas & NVME_NS_FLBAS_LBA_MASK].ds;
	if (ns->lba_shift == 0)
		ns->lba_shift = 9;
	ns->noiob = le16_to_cpu(id->noiob);
	ns->ext = ns->ms && (id->flbas & NVME_NS_FLBAS_META_EXT);
	ns->ms = le16_to_cpu(id->lbaf[id->flbas & NVME_NS_FLBAS_LBA_MASK].ms);
	/* the PI implementation requires metadata equal t10 pi tuple size */
	if (ns->ms == sizeof(struct t10_pi_tuple))
		ns->pi_type = id->dps & NVME_NS_DPS_PI_MASK;
	else
		ns->pi_type = 0;

	if (ns->noiob)
		nvme_set_chunk_size(ns);
	nvme_update_disk_info(disk, ns, id);
#ifdef CONFIG_NVME_MULTIPATH
	if (ns->head->disk)
		nvme_update_disk_info(ns->head->disk, ns, id);
#endif
}

static int nvme_revalidate_disk(struct gendisk *disk)
{
	struct nvme_ns *ns = disk->private_data;
	struct nvme_ctrl *ctrl = ns->ctrl;
	struct nvme_id_ns *id;
	struct nvme_ns_ids ids;
	int ret = 0;

	if (test_bit(NVME_NS_DEAD, &ns->flags)) {
		set_capacity(disk, 0);
		return -ENODEV;
	}

	id = nvme_identify_ns(ctrl, ns->head->ns_id);
	if (!id)
		return -ENODEV;

	if (id->ncap == 0) {
		ret = -ENODEV;
		goto out;
	}

	__nvme_revalidate_disk(disk, id);
	nvme_report_ns_ids(ctrl, ns->head->ns_id, id, &ids);
	if (!nvme_ns_ids_equal(&ns->head->ids, &ids)) {
		dev_err(ctrl->device,
			"identifiers changed for nsid %d\n", ns->head->ns_id);
		ret = -ENODEV;
	}

out:
	kfree(id);
	return ret;
}

static char nvme_pr_type(enum pr_type type)
{
	switch (type) {
	case PR_WRITE_EXCLUSIVE:
		return 1;
	case PR_EXCLUSIVE_ACCESS:
		return 2;
	case PR_WRITE_EXCLUSIVE_REG_ONLY:
		return 3;
	case PR_EXCLUSIVE_ACCESS_REG_ONLY:
		return 4;
	case PR_WRITE_EXCLUSIVE_ALL_REGS:
		return 5;
	case PR_EXCLUSIVE_ACCESS_ALL_REGS:
		return 6;
	default:
		return 0;
	}
};

static int nvme_pr_command(struct block_device *bdev, u32 cdw10,
				u64 key, u64 sa_key, u8 op)
{
	struct nvme_ns_head *head = NULL;
	struct nvme_ns *ns;
	struct nvme_command c;
	int srcu_idx, ret;
	u8 data[16] = { 0, };

	ns = nvme_get_ns_from_disk(bdev->bd_disk, &head, &srcu_idx);
	if (unlikely(!ns))
		return -EWOULDBLOCK;

	put_unaligned_le64(key, &data[0]);
	put_unaligned_le64(sa_key, &data[8]);

	memset(&c, 0, sizeof(c));
	c.common.opcode = op;
	c.common.nsid = cpu_to_le32(ns->head->ns_id);
	c.common.cdw10[0] = cpu_to_le32(cdw10);

	ret = nvme_submit_sync_cmd(ns->queue, &c, data, 16);
	nvme_put_ns_from_disk(head, srcu_idx);
	return ret;
}

static int nvme_pr_register(struct block_device *bdev, u64 old,
		u64 new, unsigned flags)
{
	u32 cdw10;

	if (flags & ~PR_FL_IGNORE_KEY)
		return -EOPNOTSUPP;

	cdw10 = old ? 2 : 0;
	cdw10 |= (flags & PR_FL_IGNORE_KEY) ? 1 << 3 : 0;
	cdw10 |= (1 << 30) | (1 << 31); /* PTPL=1 */
	return nvme_pr_command(bdev, cdw10, old, new, nvme_cmd_resv_register);
}

static int nvme_pr_reserve(struct block_device *bdev, u64 key,
		enum pr_type type, unsigned flags)
{
	u32 cdw10;

	if (flags & ~PR_FL_IGNORE_KEY)
		return -EOPNOTSUPP;

	cdw10 = nvme_pr_type(type) << 8;
	cdw10 |= ((flags & PR_FL_IGNORE_KEY) ? 1 << 3 : 0);
	return nvme_pr_command(bdev, cdw10, key, 0, nvme_cmd_resv_acquire);
}

static int nvme_pr_preempt(struct block_device *bdev, u64 old, u64 new,
		enum pr_type type, bool abort)
{
	u32 cdw10 = nvme_pr_type(type) << 8 | abort ? 2 : 1;
	return nvme_pr_command(bdev, cdw10, old, new, nvme_cmd_resv_acquire);
}

static int nvme_pr_clear(struct block_device *bdev, u64 key)
{
	u32 cdw10 = 1 | (key ? 1 << 3 : 0);
	return nvme_pr_command(bdev, cdw10, key, 0, nvme_cmd_resv_register);
}

static int nvme_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
{
	u32 cdw10 = nvme_pr_type(type) << 8 | key ? 1 << 3 : 0;
	return nvme_pr_command(bdev, cdw10, key, 0, nvme_cmd_resv_release);
}

static const struct pr_ops nvme_pr_ops = {
	.pr_register	= nvme_pr_register,
	.pr_reserve	= nvme_pr_reserve,
	.pr_release	= nvme_pr_release,
	.pr_preempt	= nvme_pr_preempt,
	.pr_clear	= nvme_pr_clear,
};

#ifdef CONFIG_BLK_SED_OPAL
int nvme_sec_submit(void *data, u16 spsp, u8 secp, void *buffer, size_t len,
		bool send)
{
	struct nvme_ctrl *ctrl = data;
	struct nvme_command cmd;

	memset(&cmd, 0, sizeof(cmd));
	if (send)
		cmd.common.opcode = nvme_admin_security_send;
	else
		cmd.common.opcode = nvme_admin_security_recv;
	cmd.common.nsid = 0;
	cmd.common.cdw10[0] = cpu_to_le32(((u32)secp) << 24 | ((u32)spsp) << 8);
	cmd.common.cdw10[1] = cpu_to_le32(len);

	return __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, NULL, buffer, len,
				      ADMIN_TIMEOUT, NVME_QID_ANY, 1, 0);
}
EXPORT_SYMBOL_GPL(nvme_sec_submit);
#endif /* CONFIG_BLK_SED_OPAL */

static const struct block_device_operations nvme_fops = {
	.owner		= THIS_MODULE,
	.ioctl		= nvme_ioctl,
	.compat_ioctl	= nvme_ioctl,
	.open		= nvme_open,
	.release	= nvme_release,
	.getgeo		= nvme_getgeo,
	.revalidate_disk= nvme_revalidate_disk,
	.pr_ops		= &nvme_pr_ops,
};

#ifdef CONFIG_NVME_MULTIPATH
static int nvme_ns_head_open(struct block_device *bdev, fmode_t mode)
{
	struct nvme_ns_head *head = bdev->bd_disk->private_data;

	if (!kref_get_unless_zero(&head->ref))
		return -ENXIO;
	return 0;
}

static void nvme_ns_head_release(struct gendisk *disk, fmode_t mode)
{
	nvme_put_ns_head(disk->private_data);
}

const struct block_device_operations nvme_ns_head_ops = {
	.owner		= THIS_MODULE,
	.open		= nvme_ns_head_open,
	.release	= nvme_ns_head_release,
	.ioctl		= nvme_ioctl,
	.compat_ioctl	= nvme_ioctl,
	.getgeo		= nvme_getgeo,
	.pr_ops		= &nvme_pr_ops,
};
#endif /* CONFIG_NVME_MULTIPATH */

static int nvme_wait_ready(struct nvme_ctrl *ctrl, u64 cap, bool enabled)
{
	unsigned long timeout =
		((NVME_CAP_TIMEOUT(cap) + 1) * HZ / 2) + jiffies;
	u32 csts, bit = enabled ? NVME_CSTS_RDY : 0;
	int ret;

	while ((ret = ctrl->ops->reg_read32(ctrl, NVME_REG_CSTS, &csts)) == 0) {
		if (csts == ~0)
			return -ENODEV;
		if ((csts & NVME_CSTS_RDY) == bit)
			break;

		msleep(100);
		if (fatal_signal_pending(current))
			return -EINTR;
		if (time_after(jiffies, timeout)) {
			dev_err(ctrl->device,
				"Device not ready; aborting %s\n", enabled ?
						"initialisation" : "reset");
			return -ENODEV;
		}
	}

	return ret;
}

/*
 * If the device has been passed off to us in an enabled state, just clear
 * the enabled bit.  The spec says we should set the 'shutdown notification
 * bits', but doing so may cause the device to complete commands to the
 * admin queue ... and we don't know what memory that might be pointing at!
 */
int nvme_disable_ctrl(struct nvme_ctrl *ctrl, u64 cap)
{
	int ret;

	ctrl->ctrl_config &= ~NVME_CC_SHN_MASK;
	ctrl->ctrl_config &= ~NVME_CC_ENABLE;

	ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
	if (ret)
		return ret;

	if (ctrl->quirks & NVME_QUIRK_DELAY_BEFORE_CHK_RDY)
		msleep(NVME_QUIRK_DELAY_AMOUNT);

	return nvme_wait_ready(ctrl, cap, false);
}
EXPORT_SYMBOL_GPL(nvme_disable_ctrl);

int nvme_enable_ctrl(struct nvme_ctrl *ctrl, u64 cap)
{
	/*
	 * Default to a 4K page size, with the intention to update this
	 * path in the future to accomodate architectures with differing
	 * kernel and IO page sizes.
	 */
	unsigned dev_page_min = NVME_CAP_MPSMIN(cap) + 12, page_shift = 12;
	int ret;

	if (page_shift < dev_page_min) {
		dev_err(ctrl->device,
			"Minimum device page size %u too large for host (%u)\n",
			1 << dev_page_min, 1 << page_shift);
		return -ENODEV;
	}

	ctrl->page_size = 1 << page_shift;

	ctrl->ctrl_config = NVME_CC_CSS_NVM;
	ctrl->ctrl_config |= (page_shift - 12) << NVME_CC_MPS_SHIFT;
	ctrl->ctrl_config |= NVME_CC_AMS_RR | NVME_CC_SHN_NONE;
	ctrl->ctrl_config |= NVME_CC_IOSQES | NVME_CC_IOCQES;
	ctrl->ctrl_config |= NVME_CC_ENABLE;

	ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
	if (ret)
		return ret;
	return nvme_wait_ready(ctrl, cap, true);
}
EXPORT_SYMBOL_GPL(nvme_enable_ctrl);

int nvme_shutdown_ctrl(struct nvme_ctrl *ctrl)
{
	unsigned long timeout = jiffies + (ctrl->shutdown_timeout * HZ);
	u32 csts;
	int ret;

	ctrl->ctrl_config &= ~NVME_CC_SHN_MASK;
	ctrl->ctrl_config |= NVME_CC_SHN_NORMAL;

	ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
	if (ret)
		return ret;

	while ((ret = ctrl->ops->reg_read32(ctrl, NVME_REG_CSTS, &csts)) == 0) {
		if ((csts & NVME_CSTS_SHST_MASK) == NVME_CSTS_SHST_CMPLT)
			break;

		msleep(100);
		if (fatal_signal_pending(current))
			return -EINTR;
		if (time_after(jiffies, timeout)) {
			dev_err(ctrl->device,
				"Device shutdown incomplete; abort shutdown\n");
			return -ENODEV;
		}
	}

	return ret;
}
EXPORT_SYMBOL_GPL(nvme_shutdown_ctrl);

static void nvme_set_queue_limits(struct nvme_ctrl *ctrl,
		struct request_queue *q)
{
	bool vwc = false;

	if (ctrl->max_hw_sectors) {
		u32 max_segments =
			(ctrl->max_hw_sectors / (ctrl->page_size >> 9)) + 1;

		blk_queue_max_hw_sectors(q, ctrl->max_hw_sectors);
		blk_queue_max_segments(q, min_t(u32, max_segments, USHRT_MAX));
	}
	if ((ctrl->quirks & NVME_QUIRK_STRIPE_SIZE) &&
	    is_power_of_2(ctrl->max_hw_sectors))
		blk_queue_chunk_sectors(q, ctrl->max_hw_sectors);
	blk_queue_virt_boundary(q, ctrl->page_size - 1);
	if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
		vwc = true;
	blk_queue_write_cache(q, vwc, vwc);
}

static int nvme_configure_timestamp(struct nvme_ctrl *ctrl)
{
	__le64 ts;
	int ret;

	if (!(ctrl->oncs & NVME_CTRL_ONCS_TIMESTAMP))
		return 0;

	ts = cpu_to_le64(ktime_to_ms(ktime_get_real()));
	ret = nvme_set_features(ctrl, NVME_FEAT_TIMESTAMP, 0, &ts, sizeof(ts),
			NULL);
	if (ret)
		dev_warn_once(ctrl->device,
			"could not set timestamp (%d)\n", ret);
	return ret;
}

static int nvme_configure_apst(struct nvme_ctrl *ctrl)
{
	/*
	 * APST (Autonomous Power State Transition) lets us program a
	 * table of power state transitions that the controller will
	 * perform automatically.  We configure it with a simple
	 * heuristic: we are willing to spend at most 2% of the time
	 * transitioning between power states.  Therefore, when running
	 * in any given state, we will enter the next lower-power
	 * non-operational state after waiting 50 * (enlat + exlat)
	 * microseconds, as long as that state's exit latency is under
	 * the requested maximum latency.
	 *
	 * We will not autonomously enter any non-operational state for
	 * which the total latency exceeds ps_max_latency_us.  Users
	 * can set ps_max_latency_us to zero to turn off APST.
	 */

	unsigned apste;
	struct nvme_feat_auto_pst *table;
	u64 max_lat_us = 0;
	int max_ps = -1;
	int ret;

	/*
	 * If APST isn't supported or if we haven't been initialized yet,
	 * then don't do anything.
	 */
	if (!ctrl->apsta)
		return 0;

	if (ctrl->npss > 31) {
		dev_warn(ctrl->device, "NPSS is invalid; not using APST\n");
		return 0;
	}

	table = kzalloc(sizeof(*table), GFP_KERNEL);
	if (!table)
		return 0;

	if (!ctrl->apst_enabled || ctrl->ps_max_latency_us == 0) {
		/* Turn off APST. */
		apste = 0;
		dev_dbg(ctrl->device, "APST disabled\n");
	} else {
		__le64 target = cpu_to_le64(0);
		int state;

		/*
		 * Walk through all states from lowest- to highest-power.
		 * According to the spec, lower-numbered states use more
		 * power.  NPSS, despite the name, is the index of the
		 * lowest-power state, not the number of states.
		 */
		for (state = (int)ctrl->npss; state >= 0; state--) {
			u64 total_latency_us, exit_latency_us, transition_ms;

			if (target)
				table->entries[state] = target;

			/*
			 * Don't allow transitions to the deepest state
			 * if it's quirked off.
			 */
			if (state == ctrl->npss &&
			    (ctrl->quirks & NVME_QUIRK_NO_DEEPEST_PS))
				continue;

			/*
			 * Is this state a useful non-operational state for
			 * higher-power states to autonomously transition to?
			 */
			if (!(ctrl->psd[state].flags &
			      NVME_PS_FLAGS_NON_OP_STATE))
				continue;

			exit_latency_us =
				(u64)le32_to_cpu(ctrl->psd[state].exit_lat);
			if (exit_latency_us > ctrl->ps_max_latency_us)
				continue;

			total_latency_us =
				exit_latency_us +
				le32_to_cpu(ctrl->psd[state].entry_lat);

			/*
			 * This state is good.  Use it as the APST idle
			 * target for higher power states.
			 */
			transition_ms = total_latency_us + 19;
			do_div(transition_ms, 20);
			if (transition_ms > (1 << 24) - 1)
				transition_ms = (1 << 24) - 1;

			target = cpu_to_le64((state << 3) |
					     (transition_ms << 8));

			if (max_ps == -1)
				max_ps = state;

			if (total_latency_us > max_lat_us)
				max_lat_us = total_latency_us;
		}

		apste = 1;

		if (max_ps == -1) {
			dev_dbg(ctrl->device, "APST enabled but no non-operational states are available\n");
		} else {
			dev_dbg(ctrl->device, "APST enabled: max PS = %d, max round-trip latency = %lluus, table = %*phN\n",
				max_ps, max_lat_us, (int)sizeof(*table), table);
		}
	}

	ret = nvme_set_features(ctrl, NVME_FEAT_AUTO_PST, apste,
				table, sizeof(*table), NULL);
	if (ret)
		dev_err(ctrl->device, "failed to set APST feature (%d)\n", ret);

	kfree(table);
	return ret;
}

static void nvme_set_latency_tolerance(struct device *dev, s32 val)
{
	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
	u64 latency;

	switch (val) {
	case PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT:
	case PM_QOS_LATENCY_ANY:
		latency = U64_MAX;
		break;

	default:
		latency = val;
	}

	if (ctrl->ps_max_latency_us != latency) {
		ctrl->ps_max_latency_us = latency;
		nvme_configure_apst(ctrl);
	}
}

struct nvme_core_quirk_entry {
	/*
	 * NVMe model and firmware strings are padded with spaces.  For
	 * simplicity, strings in the quirk table are padded with NULLs
	 * instead.
	 */
	u16 vid;
	const char *mn;
	const char *fr;
	unsigned long quirks;
};

static const struct nvme_core_quirk_entry core_quirks[] = {
	{
		/*
		 * This Toshiba device seems to die using any APST states.  See:
		 * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1678184/comments/11
		 */
		.vid = 0x1179,
		.mn = "THNSF5256GPUK TOSHIBA",
		.quirks = NVME_QUIRK_NO_APST,
	}
};

/* match is null-terminated but idstr is space-padded. */
static bool string_matches(const char *idstr, const char *match, size_t len)
{
	size_t matchlen;

	if (!match)
		return true;

	matchlen = strlen(match);
	WARN_ON_ONCE(matchlen > len);

	if (memcmp(idstr, match, matchlen))
		return false;

	for (; matchlen < len; matchlen++)
		if (idstr[matchlen] != ' ')
			return false;

	return true;
}

static bool quirk_matches(const struct nvme_id_ctrl *id,
			  const struct nvme_core_quirk_entry *q)
{
	return q->vid == le16_to_cpu(id->vid) &&
		string_matches(id->mn, q->mn, sizeof(id->mn)) &&
		string_matches(id->fr, q->fr, sizeof(id->fr));
}

static void nvme_init_subnqn(struct nvme_subsystem *subsys, struct nvme_ctrl *ctrl,
		struct nvme_id_ctrl *id)
{
	size_t nqnlen;
	int off;

	nqnlen = strnlen(id->subnqn, NVMF_NQN_SIZE);
	if (nqnlen > 0 && nqnlen < NVMF_NQN_SIZE) {
		strncpy(subsys->subnqn, id->subnqn, NVMF_NQN_SIZE);
		return;
	}

	if (ctrl->vs >= NVME_VS(1, 2, 1))
		dev_warn(ctrl->device, "missing or invalid SUBNQN field.\n");

	/* Generate a "fake" NQN per Figure 254 in NVMe 1.3 + ECN 001 */
	off = snprintf(subsys->subnqn, NVMF_NQN_SIZE,
			"nqn.2014.08.org.nvmexpress:%4x%4x",
			le16_to_cpu(id->vid), le16_to_cpu(id->ssvid));
	memcpy(subsys->subnqn + off, id->sn, sizeof(id->sn));
	off += sizeof(id->sn);
	memcpy(subsys->subnqn + off, id->mn, sizeof(id->mn));
	off += sizeof(id->mn);
	memset(subsys->subnqn + off, 0, sizeof(subsys->subnqn) - off);
}

static void __nvme_release_subsystem(struct nvme_subsystem *subsys)
{
	ida_simple_remove(&nvme_subsystems_ida, subsys->instance);
	kfree(subsys);
}

static void nvme_release_subsystem(struct device *dev)
{
	__nvme_release_subsystem(container_of(dev, struct nvme_subsystem, dev));
}

static void nvme_destroy_subsystem(struct kref *ref)
{
	struct nvme_subsystem *subsys =
			container_of(ref, struct nvme_subsystem, ref);

	mutex_lock(&nvme_subsystems_lock);
	list_del(&subsys->entry);
	mutex_unlock(&nvme_subsystems_lock);

	ida_destroy(&subsys->ns_ida);
	device_del(&subsys->dev);
	put_device(&subsys->dev);
}

static void nvme_put_subsystem(struct nvme_subsystem *subsys)
{
	kref_put(&subsys->ref, nvme_destroy_subsystem);
}

static struct nvme_subsystem *__nvme_find_get_subsystem(const char *subsysnqn)
{
	struct nvme_subsystem *subsys;

	lockdep_assert_held(&nvme_subsystems_lock);

	list_for_each_entry(subsys, &nvme_subsystems, entry) {
		if (strcmp(subsys->subnqn, subsysnqn))
			continue;
		if (!kref_get_unless_zero(&subsys->ref))
			continue;
		return subsys;
	}

	return NULL;
}

#define SUBSYS_ATTR_RO(_name, _mode, _show)			\
	struct device_attribute subsys_attr_##_name = \
		__ATTR(_name, _mode, _show, NULL)

static ssize_t nvme_subsys_show_nqn(struct device *dev,
				    struct device_attribute *attr,
				    char *buf)
{
	struct nvme_subsystem *subsys =
		container_of(dev, struct nvme_subsystem, dev);

	return snprintf(buf, PAGE_SIZE, "%s\n", subsys->subnqn);
}
static SUBSYS_ATTR_RO(subsysnqn, S_IRUGO, nvme_subsys_show_nqn);

#define nvme_subsys_show_str_function(field)				\
static ssize_t subsys_##field##_show(struct device *dev,		\
			    struct device_attribute *attr, char *buf)	\
{									\
	struct nvme_subsystem *subsys =					\
		container_of(dev, struct nvme_subsystem, dev);		\
	return sprintf(buf, "%.*s\n",					\
		       (int)sizeof(subsys->field), subsys->field);	\
}									\
static SUBSYS_ATTR_RO(field, S_IRUGO, subsys_##field##_show);

nvme_subsys_show_str_function(model);
nvme_subsys_show_str_function(serial);
nvme_subsys_show_str_function(firmware_rev);

static struct attribute *nvme_subsys_attrs[] = {
	&subsys_attr_model.attr,
	&subsys_attr_serial.attr,
	&subsys_attr_firmware_rev.attr,
	&subsys_attr_subsysnqn.attr,
	NULL,
};

static struct attribute_group nvme_subsys_attrs_group = {
	.attrs = nvme_subsys_attrs,
};

static const struct attribute_group *nvme_subsys_attrs_groups[] = {
	&nvme_subsys_attrs_group,
	NULL,
};

static int nvme_active_ctrls(struct nvme_subsystem *subsys)
{
	int count = 0;
	struct nvme_ctrl *ctrl;

	mutex_lock(&subsys->lock);
	list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) {
		if (ctrl->state != NVME_CTRL_DELETING &&
		    ctrl->state != NVME_CTRL_DEAD)
			count++;
	}
	mutex_unlock(&subsys->lock);

	return count;
}

static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
{
	struct nvme_subsystem *subsys, *found;
	int ret;

	subsys = kzalloc(sizeof(*subsys), GFP_KERNEL);
	if (!subsys)
		return -ENOMEM;
	ret = ida_simple_get(&nvme_subsystems_ida, 0, 0, GFP_KERNEL);
	if (ret < 0) {
		kfree(subsys);
		return ret;
	}
	subsys->instance = ret;
	mutex_init(&subsys->lock);
	kref_init(&subsys->ref);
	INIT_LIST_HEAD(&subsys->ctrls);
	INIT_LIST_HEAD(&subsys->nsheads);
	nvme_init_subnqn(subsys, ctrl, id);
	memcpy(subsys->serial, id->sn, sizeof(subsys->serial));
	memcpy(subsys->model, id->mn, sizeof(subsys->model));
	memcpy(subsys->firmware_rev, id->fr, sizeof(subsys->firmware_rev));
	subsys->vendor_id = le16_to_cpu(id->vid);
	subsys->cmic = id->cmic;

	subsys->dev.class = nvme_subsys_class;
	subsys->dev.release = nvme_release_subsystem;
	subsys->dev.groups = nvme_subsys_attrs_groups;
	dev_set_name(&subsys->dev, "nvme-subsys%d", subsys->instance);
	device_initialize(&subsys->dev);

	mutex_lock(&nvme_subsystems_lock);
	found = __nvme_find_get_subsystem(subsys->subnqn);
	if (found) {
		/*
		 * Verify that the subsystem actually supports multiple
		 * controllers, else bail out.
		 */
		if (nvme_active_ctrls(found) && !(id->cmic & (1 << 1))) {
			dev_err(ctrl->device,
				"ignoring ctrl due to duplicate subnqn (%s).\n",
				found->subnqn);
			nvme_put_subsystem(found);
			ret = -EINVAL;
			goto out_unlock;
		}

		__nvme_release_subsystem(subsys);
		subsys = found;
	} else {
		ret = device_add(&subsys->dev);
		if (ret) {
			dev_err(ctrl->device,
				"failed to register subsystem device.\n");
			goto out_unlock;
		}
		ida_init(&subsys->ns_ida);
		list_add_tail(&subsys->entry, &nvme_subsystems);
	}

	ctrl->subsys = subsys;
	mutex_unlock(&nvme_subsystems_lock);

	if (sysfs_create_link(&subsys->dev.kobj, &ctrl->device->kobj,
			dev_name(ctrl->device))) {
		dev_err(ctrl->device,
			"failed to create sysfs link from subsystem.\n");
		/* the transport driver will eventually put the subsystem */
		return -EINVAL;
	}

	mutex_lock(&subsys->lock);
	list_add_tail(&ctrl->subsys_entry, &subsys->ctrls);
	mutex_unlock(&subsys->lock);

	return 0;

out_unlock:
	mutex_unlock(&nvme_subsystems_lock);
	put_device(&subsys->dev);
	return ret;
}

static int nvme_get_log(struct nvme_ctrl *ctrl, u8 log_page, void *log,
			size_t size)
{
	struct nvme_command c = { };

	c.common.opcode = nvme_admin_get_log_page;
	c.common.nsid = cpu_to_le32(NVME_NSID_ALL);
	c.common.cdw10[0] = nvme_get_log_dw10(log_page, size);

	return nvme_submit_sync_cmd(ctrl->admin_q, &c, log, size);
}

static int nvme_get_effects_log(struct nvme_ctrl *ctrl)
{
	int ret;

	if (!ctrl->effects)
		ctrl->effects = kzalloc(sizeof(*ctrl->effects), GFP_KERNEL);

	if (!ctrl->effects)
		return 0;

	ret = nvme_get_log(ctrl, NVME_LOG_CMD_EFFECTS, ctrl->effects,
					sizeof(*ctrl->effects));
	if (ret) {
		kfree(ctrl->effects);
		ctrl->effects = NULL;
	}
	return ret;
}

/*
 * Initialize the cached copies of the Identify data and various controller
 * register in our nvme_ctrl structure.  This should be called as soon as
 * the admin queue is fully up and running.
 */
int nvme_init_identify(struct nvme_ctrl *ctrl)
{
	struct nvme_id_ctrl *id;
	u64 cap;
	int ret, page_shift;
	u32 max_hw_sectors;
	bool prev_apst_enabled;

	ret = ctrl->ops->reg_read32(ctrl, NVME_REG_VS, &ctrl->vs);
	if (ret) {
		dev_err(ctrl->device, "Reading VS failed (%d)\n", ret);
		return ret;
	}

	ret = ctrl->ops->reg_read64(ctrl, NVME_REG_CAP, &cap);
	if (ret) {
		dev_err(ctrl->device, "Reading CAP failed (%d)\n", ret);
		return ret;
	}
	page_shift = NVME_CAP_MPSMIN(cap) + 12;

	if (ctrl->vs >= NVME_VS(1, 1, 0))
		ctrl->subsystem = NVME_CAP_NSSRC(cap);

	ret = nvme_identify_ctrl(ctrl, &id);
	if (ret) {
		dev_err(ctrl->device, "Identify Controller failed (%d)\n", ret);
		return -EIO;
	}

	if (id->lpa & NVME_CTRL_LPA_CMD_EFFECTS_LOG) {
		ret = nvme_get_effects_log(ctrl);
		if (ret < 0)
			return ret;
	}

	if (!ctrl->identified) {
		int i;

		ret = nvme_init_subsystem(ctrl, id);
		if (ret)
			goto out_free;

		/*
		 * Check for quirks.  Quirk can depend on firmware version,
		 * so, in principle, the set of quirks present can change
		 * across a reset.  As a possible future enhancement, we
		 * could re-scan for quirks every time we reinitialize
		 * the device, but we'd have to make sure that the driver
		 * behaves intelligently if the quirks change.
		 */
		for (i = 0; i < ARRAY_SIZE(core_quirks); i++) {
			if (quirk_matches(id, &core_quirks[i]))
				ctrl->quirks |= core_quirks[i].quirks;
		}
	}

	if (force_apst && (ctrl->quirks & NVME_QUIRK_NO_DEEPEST_PS)) {
		dev_warn(ctrl->device, "forcibly allowing all power states due to nvme_core.force_apst -- use at your own risk\n");
		ctrl->quirks &= ~NVME_QUIRK_NO_DEEPEST_PS;
	}

	ctrl->oacs = le16_to_cpu(id->oacs);
	ctrl->oncs = le16_to_cpup(&id->oncs);
	atomic_set(&ctrl->abort_limit, id->acl + 1);
	ctrl->vwc = id->vwc;
	ctrl->cntlid = le16_to_cpup(&id->cntlid);
	if (id->mdts)
		max_hw_sectors = 1 << (id->mdts + page_shift - 9);
	else
		max_hw_sectors = UINT_MAX;
	ctrl->max_hw_sectors =
		min_not_zero(ctrl->max_hw_sectors, max_hw_sectors);

	nvme_set_queue_limits(ctrl, ctrl->admin_q);
	ctrl->sgls = le32_to_cpu(id->sgls);
	ctrl->kas = le16_to_cpu(id->kas);

	if (id->rtd3e) {
		/* us -> s */
		u32 transition_time = le32_to_cpu(id->rtd3e) / 1000000;

		ctrl->shutdown_timeout = clamp_t(unsigned int, transition_time,
						 shutdown_timeout, 60);

		if (ctrl->shutdown_timeout != shutdown_timeout)
			dev_info(ctrl->device,
				 "Shutdown timeout set to %u seconds\n",
				 ctrl->shutdown_timeout);
	} else
		ctrl->shutdown_timeout = shutdown_timeout;

	ctrl->npss = id->npss;
	ctrl->apsta = id->apsta;
	prev_apst_enabled = ctrl->apst_enabled;
	if (ctrl->quirks & NVME_QUIRK_NO_APST) {
		if (force_apst && id->apsta) {
			dev_warn(ctrl->device, "forcibly allowing APST due to nvme_core.force_apst -- use at your own risk\n");
			ctrl->apst_enabled = true;
		} else {
			ctrl->apst_enabled = false;
		}
	} else {
		ctrl->apst_enabled = id->apsta;
	}
	memcpy(ctrl->psd, id->psd, sizeof(ctrl->psd));

	if (ctrl->ops->flags & NVME_F_FABRICS) {
		ctrl->icdoff = le16_to_cpu(id->icdoff);
		ctrl->ioccsz = le32_to_cpu(id->ioccsz);
		ctrl->iorcsz = le32_to_cpu(id->iorcsz);
		ctrl->maxcmd = le16_to_cpu(id->maxcmd);

		/*
		 * In fabrics we need to verify the cntlid matches the
		 * admin connect
		 */
		if (ctrl->cntlid != le16_to_cpu(id->cntlid)) {
			ret = -EINVAL;
			goto out_free;
		}

		if (!ctrl->opts->discovery_nqn && !ctrl->kas) {
			dev_err(ctrl->device,
				"keep-alive support is mandatory for fabrics\n");
			ret = -EINVAL;
			goto out_free;
		}
	} else {
		ctrl->cntlid = le16_to_cpu(id->cntlid);
		ctrl->hmpre = le32_to_cpu(id->hmpre);
		ctrl->hmmin = le32_to_cpu(id->hmmin);
		ctrl->hmminds = le32_to_cpu(id->hmminds);
		ctrl->hmmaxd = le16_to_cpu(id->hmmaxd);
	}

	kfree(id);

	if (ctrl->apst_enabled && !prev_apst_enabled)
		dev_pm_qos_expose_latency_tolerance(ctrl->device);
	else if (!ctrl->apst_enabled && prev_apst_enabled)
		dev_pm_qos_hide_latency_tolerance(ctrl->device);

	ret = nvme_configure_apst(ctrl);
	if (ret < 0)
		return ret;
	
	ret = nvme_configure_timestamp(ctrl);
	if (ret < 0)
		return ret;

	ret = nvme_configure_directives(ctrl);
	if (ret < 0)
		return ret;

	ctrl->identified = true;

	return 0;

out_free:
	kfree(id);
	return ret;
}
EXPORT_SYMBOL_GPL(nvme_init_identify);

static int nvme_dev_open(struct inode *inode, struct file *file)
{
	struct nvme_ctrl *ctrl =
		container_of(inode->i_cdev, struct nvme_ctrl, cdev);

	switch (ctrl->state) {
	case NVME_CTRL_LIVE:
	case NVME_CTRL_ADMIN_ONLY:
		break;
	default:
		return -EWOULDBLOCK;
	}

	file->private_data = ctrl;
	return 0;
}

static int nvme_dev_user_cmd(struct nvme_ctrl *ctrl, void __user *argp)
{
	struct nvme_ns *ns;
	int ret;

	mutex_lock(&ctrl->namespaces_mutex);
	if (list_empty(&ctrl->namespaces)) {
		ret = -ENOTTY;
		goto out_unlock;
	}

	ns = list_first_entry(&ctrl->namespaces, struct nvme_ns, list);
	if (ns != list_last_entry(&ctrl->namespaces, struct nvme_ns, list)) {
		dev_warn(ctrl->device,
			"NVME_IOCTL_IO_CMD not supported when multiple namespaces present!\n");
		ret = -EINVAL;
		goto out_unlock;
	}

	dev_warn(ctrl->device,
		"using deprecated NVME_IOCTL_IO_CMD ioctl on the char device!\n");
	kref_get(&ns->kref);
	mutex_unlock(&ctrl->namespaces_mutex);

	ret = nvme_user_cmd(ctrl, ns, argp);
	nvme_put_ns(ns);
	return ret;

out_unlock:
	mutex_unlock(&ctrl->namespaces_mutex);
	return ret;
}

static long nvme_dev_ioctl(struct file *file, unsigned int cmd,
		unsigned long arg)
{
	struct nvme_ctrl *ctrl = file->private_data;
	void __user *argp = (void __user *)arg;

	switch (cmd) {
	case NVME_IOCTL_ADMIN_CMD:
		return nvme_user_cmd(ctrl, NULL, argp);
	case NVME_IOCTL_IO_CMD:
		return nvme_dev_user_cmd(ctrl, argp);
	case NVME_IOCTL_RESET:
		dev_warn(ctrl->device, "resetting controller\n");
		return nvme_reset_ctrl_sync(ctrl);
	case NVME_IOCTL_SUBSYS_RESET:
		return nvme_reset_subsystem(ctrl);
	case NVME_IOCTL_RESCAN:
		nvme_queue_scan(ctrl);
		return 0;
	default:
		return -ENOTTY;
	}
}

static const struct file_operations nvme_dev_fops = {
	.owner		= THIS_MODULE,
	.open		= nvme_dev_open,
	.unlocked_ioctl	= nvme_dev_ioctl,
	.compat_ioctl	= nvme_dev_ioctl,
};

static ssize_t nvme_sysfs_reset(struct device *dev,
				struct device_attribute *attr, const char *buf,
				size_t count)
{
	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
	int ret;

	ret = nvme_reset_ctrl_sync(ctrl);
	if (ret < 0)
		return ret;
	return count;
}
static DEVICE_ATTR(reset_controller, S_IWUSR, NULL, nvme_sysfs_reset);

static ssize_t nvme_sysfs_rescan(struct device *dev,
				struct device_attribute *attr, const char *buf,
				size_t count)
{
	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);

	nvme_queue_scan(ctrl);
	return count;
}
static DEVICE_ATTR(rescan_controller, S_IWUSR, NULL, nvme_sysfs_rescan);

static inline struct nvme_ns_head *dev_to_ns_head(struct device *dev)
{
	struct gendisk *disk = dev_to_disk(dev);

	if (disk->fops == &nvme_fops)
		return nvme_get_ns_from_dev(dev)->head;
	else
		return disk->private_data;
}

static ssize_t wwid_show(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	struct nvme_ns_head *head = dev_to_ns_head(dev);
	struct nvme_ns_ids *ids = &head->ids;
	struct nvme_subsystem *subsys = head->subsys;
	int serial_len = sizeof(subsys->serial);
	int model_len = sizeof(subsys->model);

	if (!uuid_is_null(&ids->uuid))
		return sprintf(buf, "uuid.%pU\n", &ids->uuid);

	if (memchr_inv(ids->nguid, 0, sizeof(ids->nguid)))
		return sprintf(buf, "eui.%16phN\n", ids->nguid);

	if (memchr_inv(ids->eui64, 0, sizeof(ids->eui64)))
		return sprintf(buf, "eui.%8phN\n", ids->eui64);

	while (serial_len > 0 && (subsys->serial[serial_len - 1] == ' ' ||
				  subsys->serial[serial_len - 1] == '\0'))
		serial_len--;
	while (model_len > 0 && (subsys->model[model_len - 1] == ' ' ||
				 subsys->model[model_len - 1] == '\0'))
		model_len--;

	return sprintf(buf, "nvme.%04x-%*phN-%*phN-%08x\n", subsys->vendor_id,
		serial_len, subsys->serial, model_len, subsys->model,
		head->ns_id);
}
static DEVICE_ATTR(wwid, S_IRUGO, wwid_show, NULL);

static ssize_t nguid_show(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	return sprintf(buf, "%pU\n", dev_to_ns_head(dev)->ids.nguid);
}
static DEVICE_ATTR(nguid, S_IRUGO, nguid_show, NULL);

static ssize_t uuid_show(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	struct nvme_ns_ids *ids = &dev_to_ns_head(dev)->ids;

	/* For backward compatibility expose the NGUID to userspace if
	 * we have no UUID set
	 */
	if (uuid_is_null(&ids->uuid)) {
		printk_ratelimited(KERN_WARNING
				   "No UUID available providing old NGUID\n");
		return sprintf(buf, "%pU\n", ids->nguid);
	}
	return sprintf(buf, "%pU\n", &ids->uuid);
}
static DEVICE_ATTR(uuid, S_IRUGO, uuid_show, NULL);

static ssize_t eui_show(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	return sprintf(buf, "%8ph\n", dev_to_ns_head(dev)->ids.eui64);
}
static DEVICE_ATTR(eui, S_IRUGO, eui_show, NULL);

static ssize_t nsid_show(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	return sprintf(buf, "%d\n", dev_to_ns_head(dev)->ns_id);
}
static DEVICE_ATTR(nsid, S_IRUGO, nsid_show, NULL);

static struct attribute *nvme_ns_id_attrs[] = {
	&dev_attr_wwid.attr,
	&dev_attr_uuid.attr,
	&dev_attr_nguid.attr,
	&dev_attr_eui.attr,
	&dev_attr_nsid.attr,
	NULL,
};

static umode_t nvme_ns_id_attrs_are_visible(struct kobject *kobj,
		struct attribute *a, int n)
{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct nvme_ns_ids *ids = &dev_to_ns_head(dev)->ids;

	if (a == &dev_attr_uuid.attr) {
		if (uuid_is_null(&ids->uuid) &&
		    !memchr_inv(ids->nguid, 0, sizeof(ids->nguid)))
			return 0;
	}
	if (a == &dev_attr_nguid.attr) {
		if (!memchr_inv(ids->nguid, 0, sizeof(ids->nguid)))
			return 0;
	}
	if (a == &dev_attr_eui.attr) {
		if (!memchr_inv(ids->eui64, 0, sizeof(ids->eui64)))
			return 0;
	}
	return a->mode;
}

const struct attribute_group nvme_ns_id_attr_group = {
	.attrs		= nvme_ns_id_attrs,
	.is_visible	= nvme_ns_id_attrs_are_visible,
};

#define nvme_show_str_function(field)						\
static ssize_t  field##_show(struct device *dev,				\
			    struct device_attribute *attr, char *buf)		\
{										\
        struct nvme_ctrl *ctrl = dev_get_drvdata(dev);				\
        return sprintf(buf, "%.*s\n",						\
		(int)sizeof(ctrl->subsys->field), ctrl->subsys->field);		\
}										\
static DEVICE_ATTR(field, S_IRUGO, field##_show, NULL);

nvme_show_str_function(model);
nvme_show_str_function(serial);
nvme_show_str_function(firmware_rev);

#define nvme_show_int_function(field)						\
static ssize_t  field##_show(struct device *dev,				\
			    struct device_attribute *attr, char *buf)		\
{										\
        struct nvme_ctrl *ctrl = dev_get_drvdata(dev);				\
        return sprintf(buf, "%d\n", ctrl->field);	\
}										\
static DEVICE_ATTR(field, S_IRUGO, field##_show, NULL);

nvme_show_int_function(cntlid);

static ssize_t nvme_sysfs_delete(struct device *dev,
				struct device_attribute *attr, const char *buf,
				size_t count)
{
	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);

	if (device_remove_file_self(dev, attr))
		nvme_delete_ctrl_sync(ctrl);
	return count;
}
static DEVICE_ATTR(delete_controller, S_IWUSR, NULL, nvme_sysfs_delete);

static ssize_t nvme_sysfs_show_transport(struct device *dev,
					 struct device_attribute *attr,
					 char *buf)
{
	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%s\n", ctrl->ops->name);
}
static DEVICE_ATTR(transport, S_IRUGO, nvme_sysfs_show_transport, NULL);

static ssize_t nvme_sysfs_show_state(struct device *dev,
				     struct device_attribute *attr,
				     char *buf)
{
	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
	static const char *const state_name[] = {
		[NVME_CTRL_NEW]		= "new",
		[NVME_CTRL_LIVE]	= "live",
		[NVME_CTRL_ADMIN_ONLY]	= "only-admin",
		[NVME_CTRL_RESETTING]	= "resetting",
		[NVME_CTRL_RECONNECTING]= "reconnecting",
		[NVME_CTRL_DELETING]	= "deleting",
		[NVME_CTRL_DEAD]	= "dead",
	};

	if ((unsigned)ctrl->state < ARRAY_SIZE(state_name) &&
	    state_name[ctrl->state])
		return sprintf(buf, "%s\n", state_name[ctrl->state]);

	return sprintf(buf, "unknown state\n");
}

static DEVICE_ATTR(state, S_IRUGO, nvme_sysfs_show_state, NULL);

static ssize_t nvme_sysfs_show_subsysnqn(struct device *dev,
					 struct device_attribute *attr,
					 char *buf)
{
	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%s\n", ctrl->subsys->subnqn);
}
static DEVICE_ATTR(subsysnqn, S_IRUGO, nvme_sysfs_show_subsysnqn, NULL);

static ssize_t nvme_sysfs_show_address(struct device *dev,
					 struct device_attribute *attr,
					 char *buf)
{
	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);

	return ctrl->ops->get_address(ctrl, buf, PAGE_SIZE);
}
static DEVICE_ATTR(address, S_IRUGO, nvme_sysfs_show_address, NULL);

static struct attribute *nvme_dev_attrs[] = {
	&dev_attr_reset_controller.attr,
	&dev_attr_rescan_controller.attr,
	&dev_attr_model.attr,
	&dev_attr_serial.attr,
	&dev_attr_firmware_rev.attr,
	&dev_attr_cntlid.attr,
	&dev_attr_delete_controller.attr,
	&dev_attr_transport.attr,
	&dev_attr_subsysnqn.attr,
	&dev_attr_address.attr,
	&dev_attr_state.attr,
	NULL
};

static umode_t nvme_dev_attrs_are_visible(struct kobject *kobj,
		struct attribute *a, int n)
{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);

	if (a == &dev_attr_delete_controller.attr && !ctrl->ops->delete_ctrl)
		return 0;
	if (a == &dev_attr_address.attr && !ctrl->ops->get_address)
		return 0;

	return a->mode;
}

static struct attribute_group nvme_dev_attrs_group = {
	.attrs		= nvme_dev_attrs,
	.is_visible	= nvme_dev_attrs_are_visible,
};

static const struct attribute_group *nvme_dev_attr_groups[] = {
	&nvme_dev_attrs_group,
	NULL,
};

static struct nvme_ns_head *__nvme_find_ns_head(struct nvme_subsystem *subsys,
		unsigned nsid)
{
	struct nvme_ns_head *h;

	lockdep_assert_held(&subsys->lock);

	list_for_each_entry(h, &subsys->nsheads, entry) {
		if (h->ns_id == nsid && kref_get_unless_zero(&h->ref))
			return h;
	}

	return NULL;
}

static int __nvme_check_ids(struct nvme_subsystem *subsys,
		struct nvme_ns_head *new)
{
	struct nvme_ns_head *h;

	lockdep_assert_held(&subsys->lock);

	list_for_each_entry(h, &subsys->nsheads, entry) {
		if (nvme_ns_ids_valid(&new->ids) &&
		    nvme_ns_ids_equal(&new->ids, &h->ids))
			return -EINVAL;
	}

	return 0;
}

static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
		unsigned nsid, struct nvme_id_ns *id)
{
	struct nvme_ns_head *head;
	int ret = -ENOMEM;

	head = kzalloc(sizeof(*head), GFP_KERNEL);
	if (!head)
		goto out;
	ret = ida_simple_get(&ctrl->subsys->ns_ida, 1, 0, GFP_KERNEL);
	if (ret < 0)
		goto out_free_head;
	head->instance = ret;
	INIT_LIST_HEAD(&head->list);
	init_srcu_struct(&head->srcu);
	head->subsys = ctrl->subsys;
	head->ns_id = nsid;
	kref_init(&head->ref);

	nvme_report_ns_ids(ctrl, nsid, id, &head->ids);

	ret = __nvme_check_ids(ctrl->subsys, head);
	if (ret) {
		dev_err(ctrl->device,
			"duplicate IDs for nsid %d\n", nsid);
		goto out_cleanup_srcu;
	}

	ret = nvme_mpath_alloc_disk(ctrl, head);
	if (ret)
		goto out_cleanup_srcu;

	list_add_tail(&head->entry, &ctrl->subsys->nsheads);
	return head;
out_cleanup_srcu:
	cleanup_srcu_struct(&head->srcu);
	ida_simple_remove(&ctrl->subsys->ns_ida, head->instance);
out_free_head:
	kfree(head);
out:
	return ERR_PTR(ret);
}

static int nvme_init_ns_head(struct nvme_ns *ns, unsigned nsid,
		struct nvme_id_ns *id, bool *new)
{
	struct nvme_ctrl *ctrl = ns->ctrl;
	bool is_shared = id->nmic & (1 << 0);
	struct nvme_ns_head *head = NULL;
	int ret = 0;

	mutex_lock(&ctrl->subsys->lock);
	if (is_shared)
		head = __nvme_find_ns_head(ctrl->subsys, nsid);
	if (!head) {
		head = nvme_alloc_ns_head(ctrl, nsid, id);
		if (IS_ERR(head)) {
			ret = PTR_ERR(head);
			goto out_unlock;
		}

		*new = true;
	} else {
		struct nvme_ns_ids ids;

		nvme_report_ns_ids(ctrl, nsid, id, &ids);
		if (!nvme_ns_ids_equal(&head->ids, &ids)) {
			dev_err(ctrl->device,
				"IDs don't match for shared namespace %d\n",
					nsid);
			ret = -EINVAL;
			goto out_unlock;
		}

		*new = false;
	}

	list_add_tail(&ns->siblings, &head->list);
	ns->head = head;

out_unlock:
	mutex_unlock(&ctrl->subsys->lock);
	return ret;
}

static int ns_cmp(void *priv, struct list_head *a, struct list_head *b)
{
	struct nvme_ns *nsa = container_of(a, struct nvme_ns, list);
	struct nvme_ns *nsb = container_of(b, struct nvme_ns, list);

	return nsa->head->ns_id - nsb->head->ns_id;
}

static struct nvme_ns *nvme_find_get_ns(struct nvme_ctrl *ctrl, unsigned nsid)
{
	struct nvme_ns *ns, *ret = NULL;

	mutex_lock(&ctrl->namespaces_mutex);
	list_for_each_entry(ns, &ctrl->namespaces, list) {
		if (ns->head->ns_id == nsid) {
			if (!kref_get_unless_zero(&ns->kref))
				continue;
			ret = ns;
			break;
		}
		if (ns->head->ns_id > nsid)
			break;
	}
	mutex_unlock(&ctrl->namespaces_mutex);
	return ret;
}

static int nvme_setup_streams_ns(struct nvme_ctrl *ctrl, struct nvme_ns *ns)
{
	struct streams_directive_params s;
	int ret;

	if (!ctrl->nr_streams)
		return 0;

	ret = nvme_get_stream_params(ctrl, &s, ns->head->ns_id);
	if (ret)
		return ret;

	ns->sws = le32_to_cpu(s.sws);
	ns->sgs = le16_to_cpu(s.sgs);

	if (ns->sws) {
		unsigned int bs = 1 << ns->lba_shift;

		blk_queue_io_min(ns->queue, bs * ns->sws);
		if (ns->sgs)
			blk_queue_io_opt(ns->queue, bs * ns->sws * ns->sgs);
	}

	return 0;
}

static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
{
	struct nvme_ns *ns;
	struct gendisk *disk;
	struct nvme_id_ns *id;
	char disk_name[DISK_NAME_LEN];
	int node = dev_to_node(ctrl->dev), flags = GENHD_FL_EXT_DEVT;
	bool new = true;

	ns = kzalloc_node(sizeof(*ns), GFP_KERNEL, node);
	if (!ns)
		return;

	ns->queue = blk_mq_init_queue(ctrl->tagset);
	if (IS_ERR(ns->queue))
		goto out_free_ns;
	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, ns->queue);
	ns->queue->queuedata = ns;
	ns->ctrl = ctrl;

	kref_init(&ns->kref);
	ns->lba_shift = 9; /* set to a default value for 512 until disk is validated */

	blk_queue_logical_block_size(ns->queue, 1 << ns->lba_shift);
	nvme_set_queue_limits(ctrl, ns->queue);

	id = nvme_identify_ns(ctrl, nsid);
	if (!id)
		goto out_free_queue;

	if (id->ncap == 0)
		goto out_free_id;

	if (nvme_init_ns_head(ns, nsid, id, &new))
		goto out_free_id;
	nvme_setup_streams_ns(ctrl, ns);
	
#ifdef CONFIG_NVME_MULTIPATH
	/*
	 * If multipathing is enabled we need to always use the subsystem
	 * instance number for numbering our devices to avoid conflicts
	 * between subsystems that have multiple controllers and thus use
	 * the multipath-aware subsystem node and those that have a single
	 * controller and use the controller node directly.
	 */
	if (ns->head->disk) {
		sprintf(disk_name, "nvme%dc%dn%d", ctrl->subsys->instance,
				ctrl->cntlid, ns->head->instance);
		flags = GENHD_FL_HIDDEN;
	} else {
		sprintf(disk_name, "nvme%dn%d", ctrl->subsys->instance,
				ns->head->instance);
	}
#else
	/*
	 * But without the multipath code enabled, multiple controller per
	 * subsystems are visible as devices and thus we cannot use the
	 * subsystem instance.
	 */
	sprintf(disk_name, "nvme%dn%d", ctrl->instance, ns->head->instance);
#endif

	if ((ctrl->quirks & NVME_QUIRK_LIGHTNVM) && id->vs[0] == 0x1) {
		if (nvme_nvm_register(ns, disk_name, node)) {
			dev_warn(ctrl->device, "LightNVM init failure\n");
			goto out_unlink_ns;
		}
	}

	disk = alloc_disk_node(0, node);
	if (!disk)
		goto out_unlink_ns;

	disk->fops = &nvme_fops;
	disk->private_data = ns;
	disk->queue = ns->queue;
	disk->flags = flags;
	memcpy(disk->disk_name, disk_name, DISK_NAME_LEN);
	ns->disk = disk;

	__nvme_revalidate_disk(disk, id);

	mutex_lock(&ctrl->namespaces_mutex);
	list_add_tail(&ns->list, &ctrl->namespaces);
	mutex_unlock(&ctrl->namespaces_mutex);

	nvme_get_ctrl(ctrl);

	kfree(id);

	device_add_disk(ctrl->device, ns->disk);
	if (sysfs_create_group(&disk_to_dev(ns->disk)->kobj,
					&nvme_ns_id_attr_group))
		pr_warn("%s: failed to create sysfs group for identification\n",
			ns->disk->disk_name);
	if (ns->ndev && nvme_nvm_register_sysfs(ns))
		pr_warn("%s: failed to register lightnvm sysfs group for identification\n",
			ns->disk->disk_name);

	if (new)
		nvme_mpath_add_disk(ns->head);
	nvme_mpath_add_disk_links(ns);
	return;
 out_unlink_ns:
	mutex_lock(&ctrl->subsys->lock);
	list_del_rcu(&ns->siblings);
	mutex_unlock(&ctrl->subsys->lock);
 out_free_id:
	kfree(id);
 out_free_queue:
	blk_cleanup_queue(ns->queue);
 out_free_ns:
	kfree(ns);
}

static void nvme_ns_remove(struct nvme_ns *ns)
{
	if (test_and_set_bit(NVME_NS_REMOVING, &ns->flags))
		return;

	if (ns->disk && ns->disk->flags & GENHD_FL_UP) {
		nvme_mpath_remove_disk_links(ns);
		sysfs_remove_group(&disk_to_dev(ns->disk)->kobj,
					&nvme_ns_id_attr_group);
		if (ns->ndev)
			nvme_nvm_unregister_sysfs(ns);
		del_gendisk(ns->disk);
		blk_cleanup_queue(ns->queue);
		if (blk_get_integrity(ns->disk))
			blk_integrity_unregister(ns->disk);
	}

	mutex_lock(&ns->ctrl->subsys->lock);
	nvme_mpath_clear_current_path(ns);
	list_del_rcu(&ns->siblings);
	mutex_unlock(&ns->ctrl->subsys->lock);

	mutex_lock(&ns->ctrl->namespaces_mutex);
	list_del_init(&ns->list);
	mutex_unlock(&ns->ctrl->namespaces_mutex);

	synchronize_srcu(&ns->head->srcu);
	nvme_mpath_check_last_path(ns);
	nvme_put_ns(ns);
}

static void nvme_validate_ns(struct nvme_ctrl *ctrl, unsigned nsid)
{
	struct nvme_ns *ns;

	ns = nvme_find_get_ns(ctrl, nsid);
	if (ns) {
		if (ns->disk && revalidate_disk(ns->disk))
			nvme_ns_remove(ns);
		nvme_put_ns(ns);
	} else
		nvme_alloc_ns(ctrl, nsid);
}

static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
					unsigned nsid)
{
	struct nvme_ns *ns, *next;

	list_for_each_entry_safe(ns, next, &ctrl->namespaces, list) {
		if (ns->head->ns_id > nsid)
			nvme_ns_remove(ns);
	}
}

static int nvme_scan_ns_list(struct nvme_ctrl *ctrl, unsigned nn)
{
	struct nvme_ns *ns;
	__le32 *ns_list;
	unsigned i, j, nsid, prev = 0, num_lists = DIV_ROUND_UP(nn, 1024);
	int ret = 0;

	ns_list = kzalloc(0x1000, GFP_KERNEL);
	if (!ns_list)
		return -ENOMEM;

	for (i = 0; i < num_lists; i++) {
		ret = nvme_identify_ns_list(ctrl, prev, ns_list);
		if (ret)
			goto free;

		for (j = 0; j < min(nn, 1024U); j++) {
			nsid = le32_to_cpu(ns_list[j]);
			if (!nsid)
				goto out;

			nvme_validate_ns(ctrl, nsid);

			while (++prev < nsid) {
				ns = nvme_find_get_ns(ctrl, prev);
				if (ns) {
					nvme_ns_remove(ns);
					nvme_put_ns(ns);
				}
			}
		}
		nn -= j;
	}
 out:
	nvme_remove_invalid_namespaces(ctrl, prev);
 free:
	kfree(ns_list);
	return ret;
}

static void nvme_scan_ns_sequential(struct nvme_ctrl *ctrl, unsigned nn)
{
	unsigned i;

	for (i = 1; i <= nn; i++)
		nvme_validate_ns(ctrl, i);

	nvme_remove_invalid_namespaces(ctrl, nn);
}

static void nvme_scan_work(struct work_struct *work)
{
	struct nvme_ctrl *ctrl =
		container_of(work, struct nvme_ctrl, scan_work);
	struct nvme_id_ctrl *id;
	unsigned nn;

	if (ctrl->state != NVME_CTRL_LIVE)
		return;

	WARN_ON_ONCE(!ctrl->tagset);

	if (nvme_identify_ctrl(ctrl, &id))
		return;

	nn = le32_to_cpu(id->nn);
	if (ctrl->vs >= NVME_VS(1, 1, 0) &&
	    !(ctrl->quirks & NVME_QUIRK_IDENTIFY_CNS)) {
		if (!nvme_scan_ns_list(ctrl, nn))
			goto done;
	}
	nvme_scan_ns_sequential(ctrl, nn);
 done:
	mutex_lock(&ctrl->namespaces_mutex);
	list_sort(NULL, &ctrl->namespaces, ns_cmp);
	mutex_unlock(&ctrl->namespaces_mutex);
	kfree(id);
}

void nvme_queue_scan(struct nvme_ctrl *ctrl)
{
	/*
	 * Only new queue scan work when admin and IO queues are both alive
	 */
	if (ctrl->state == NVME_CTRL_LIVE)
		queue_work(nvme_wq, &ctrl->scan_work);
}
EXPORT_SYMBOL_GPL(nvme_queue_scan);

/*
 * This function iterates the namespace list unlocked to allow recovery from
 * controller failure. It is up to the caller to ensure the namespace list is
 * not modified by scan work while this function is executing.
 */
void nvme_remove_namespaces(struct nvme_ctrl *ctrl)
{
	struct nvme_ns *ns, *next;

	/*
	 * The dead states indicates the controller was not gracefully
	 * disconnected. In that case, we won't be able to flush any data while
	 * removing the namespaces' disks; fail all the queues now to avoid
	 * potentially having to clean up the failed sync later.
	 */
	if (ctrl->state == NVME_CTRL_DEAD)
		nvme_kill_queues(ctrl);

	list_for_each_entry_safe(ns, next, &ctrl->namespaces, list)
		nvme_ns_remove(ns);
}
EXPORT_SYMBOL_GPL(nvme_remove_namespaces);

static void nvme_aen_uevent(struct nvme_ctrl *ctrl)
{
	char *envp[2] = { NULL, NULL };
	u32 aen_result = ctrl->aen_result;

	ctrl->aen_result = 0;
	if (!aen_result)
		return;

	envp[0] = kasprintf(GFP_KERNEL, "NVME_AEN=%#08x", aen_result);
	if (!envp[0])
		return;
	kobject_uevent_env(&ctrl->device->kobj, KOBJ_CHANGE, envp);
	kfree(envp[0]);
}

static void nvme_async_event_work(struct work_struct *work)
{
	struct nvme_ctrl *ctrl =
		container_of(work, struct nvme_ctrl, async_event_work);

	nvme_aen_uevent(ctrl);
	ctrl->ops->submit_async_event(ctrl);
}

static bool nvme_ctrl_pp_status(struct nvme_ctrl *ctrl)
{

	u32 csts;

	if (ctrl->ops->reg_read32(ctrl, NVME_REG_CSTS, &csts))
		return false;

	if (csts == ~0)
		return false;

	return ((ctrl->ctrl_config & NVME_CC_ENABLE) && (csts & NVME_CSTS_PP));
}

static void nvme_get_fw_slot_info(struct nvme_ctrl *ctrl)
{
	struct nvme_fw_slot_info_log *log;

	log = kmalloc(sizeof(*log), GFP_KERNEL);
	if (!log)
		return;

	if (nvme_get_log(ctrl, NVME_LOG_FW_SLOT, log, sizeof(*log)))
		dev_warn(ctrl->device,
				"Get FW SLOT INFO log error\n");
	kfree(log);
}

static void nvme_fw_act_work(struct work_struct *work)
{
	struct nvme_ctrl *ctrl = container_of(work,
				struct nvme_ctrl, fw_act_work);
	unsigned long fw_act_timeout;

	if (ctrl->mtfa)
		fw_act_timeout = jiffies +
				msecs_to_jiffies(ctrl->mtfa * 100);
	else
		fw_act_timeout = jiffies +
				msecs_to_jiffies(admin_timeout * 1000);

	nvme_stop_queues(ctrl);
	while (nvme_ctrl_pp_status(ctrl)) {
		if (time_after(jiffies, fw_act_timeout)) {
			dev_warn(ctrl->device,
				"Fw activation timeout, reset controller\n");
			nvme_reset_ctrl(ctrl);
			break;
		}
		msleep(100);
	}

	if (ctrl->state != NVME_CTRL_LIVE)
		return;

	nvme_start_queues(ctrl);
	/* read FW slot information to clear the AER */
	nvme_get_fw_slot_info(ctrl);
}

void nvme_complete_async_event(struct nvme_ctrl *ctrl, __le16 status,
		union nvme_result *res)
{
	u32 result = le32_to_cpu(res->u32);

	if (le16_to_cpu(status) >> 1 != NVME_SC_SUCCESS)
		return;

	switch (result & 0x7) {
	case NVME_AER_ERROR:
	case NVME_AER_SMART:
	case NVME_AER_CSS:
	case NVME_AER_VS:
		ctrl->aen_result = result;
		break;
	default:
		break;
	}

	switch (result & 0xff07) {
	case NVME_AER_NOTICE_NS_CHANGED:
		dev_info(ctrl->device, "rescanning\n");
		nvme_queue_scan(ctrl);
		break;
	case NVME_AER_NOTICE_FW_ACT_STARTING:
		queue_work(nvme_wq, &ctrl->fw_act_work);
		break;
	default:
		dev_warn(ctrl->device, "async event result %08x\n", result);
	}
	queue_work(nvme_wq, &ctrl->async_event_work);
}
EXPORT_SYMBOL_GPL(nvme_complete_async_event);

void nvme_stop_ctrl(struct nvme_ctrl *ctrl)
{
	nvme_stop_keep_alive(ctrl);
	flush_work(&ctrl->async_event_work);
	flush_work(&ctrl->scan_work);
	cancel_work_sync(&ctrl->fw_act_work);
}
EXPORT_SYMBOL_GPL(nvme_stop_ctrl);

void nvme_start_ctrl(struct nvme_ctrl *ctrl)
{
	if (ctrl->kato)
		nvme_start_keep_alive(ctrl);

	if (ctrl->queue_count > 1) {
		nvme_queue_scan(ctrl);
		queue_work(nvme_wq, &ctrl->async_event_work);
		nvme_start_queues(ctrl);
	}
}
EXPORT_SYMBOL_GPL(nvme_start_ctrl);

void nvme_uninit_ctrl(struct nvme_ctrl *ctrl)
{
	cdev_device_del(&ctrl->cdev, ctrl->device);
}
EXPORT_SYMBOL_GPL(nvme_uninit_ctrl);

static void nvme_free_ctrl(struct device *dev)
{
	struct nvme_ctrl *ctrl =
		container_of(dev, struct nvme_ctrl, ctrl_device);
	struct nvme_subsystem *subsys = ctrl->subsys;

	ida_simple_remove(&nvme_instance_ida, ctrl->instance);
	kfree(ctrl->effects);

	if (subsys) {
		mutex_lock(&subsys->lock);
		list_del(&ctrl->subsys_entry);
		mutex_unlock(&subsys->lock);
		sysfs_remove_link(&subsys->dev.kobj, dev_name(ctrl->device));
	}

	ctrl->ops->free_ctrl(ctrl);

	if (subsys)
		nvme_put_subsystem(subsys);
}

/*
 * Initialize a NVMe controller structures.  This needs to be called during
 * earliest initialization so that we have the initialized structured around
 * during probing.
 */
int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
		const struct nvme_ctrl_ops *ops, unsigned long quirks)
{
	int ret;

	ctrl->state = NVME_CTRL_NEW;
	spin_lock_init(&ctrl->lock);
	INIT_LIST_HEAD(&ctrl->namespaces);
	mutex_init(&ctrl->namespaces_mutex);
	ctrl->dev = dev;
	ctrl->ops = ops;
	ctrl->quirks = quirks;
	INIT_WORK(&ctrl->scan_work, nvme_scan_work);
	INIT_WORK(&ctrl->async_event_work, nvme_async_event_work);
	INIT_WORK(&ctrl->fw_act_work, nvme_fw_act_work);
	INIT_WORK(&ctrl->delete_work, nvme_delete_ctrl_work);

	ret = ida_simple_get(&nvme_instance_ida, 0, 0, GFP_KERNEL);
	if (ret < 0)
		goto out;
	ctrl->instance = ret;

	device_initialize(&ctrl->ctrl_device);
	ctrl->device = &ctrl->ctrl_device;
	ctrl->device->devt = MKDEV(MAJOR(nvme_chr_devt), ctrl->instance);
	ctrl->device->class = nvme_class;
	ctrl->device->parent = ctrl->dev;
	ctrl->device->groups = nvme_dev_attr_groups;
	ctrl->device->release = nvme_free_ctrl;
	dev_set_drvdata(ctrl->device, ctrl);
	ret = dev_set_name(ctrl->device, "nvme%d", ctrl->instance);
	if (ret)
		goto out_release_instance;

	cdev_init(&ctrl->cdev, &nvme_dev_fops);
	ctrl->cdev.owner = ops->module;
	ret = cdev_device_add(&ctrl->cdev, ctrl->device);
	if (ret)
		goto out_free_name;

	/*
	 * Initialize latency tolerance controls.  The sysfs files won't
	 * be visible to userspace unless the device actually supports APST.
	 */
	ctrl->device->power.set_latency_tolerance = nvme_set_latency_tolerance;
	dev_pm_qos_update_user_latency_tolerance(ctrl->device,
		min(default_ps_max_latency_us, (unsigned long)S32_MAX));

	return 0;
out_free_name:
	kfree_const(dev->kobj.name);
out_release_instance:
	ida_simple_remove(&nvme_instance_ida, ctrl->instance);
out:
	return ret;
}
EXPORT_SYMBOL_GPL(nvme_init_ctrl);

/**
 * nvme_kill_queues(): Ends all namespace queues
 * @ctrl: the dead controller that needs to end
 *
 * Call this function when the driver determines it is unable to get the
 * controller in a state capable of servicing IO.
 */
void nvme_kill_queues(struct nvme_ctrl *ctrl)
{
	struct nvme_ns *ns;

	mutex_lock(&ctrl->namespaces_mutex);

	/* Forcibly unquiesce queues to avoid blocking dispatch */
	if (ctrl->admin_q)
		blk_mq_unquiesce_queue(ctrl->admin_q);

	list_for_each_entry(ns, &ctrl->namespaces, list) {
		/*
		 * Revalidating a dead namespace sets capacity to 0. This will
		 * end buffered writers dirtying pages that can't be synced.
		 */
		if (!ns->disk || test_and_set_bit(NVME_NS_DEAD, &ns->flags))
			continue;
		revalidate_disk(ns->disk);
		blk_set_queue_dying(ns->queue);

		/* Forcibly unquiesce queues to avoid blocking dispatch */
		blk_mq_unquiesce_queue(ns->queue);
	}
	mutex_unlock(&ctrl->namespaces_mutex);
}
EXPORT_SYMBOL_GPL(nvme_kill_queues);

void nvme_unfreeze(struct nvme_ctrl *ctrl)
{
	struct nvme_ns *ns;

	mutex_lock(&ctrl->namespaces_mutex);
	list_for_each_entry(ns, &ctrl->namespaces, list)
		blk_mq_unfreeze_queue(ns->queue);
	mutex_unlock(&ctrl->namespaces_mutex);
}
EXPORT_SYMBOL_GPL(nvme_unfreeze);

void nvme_wait_freeze_timeout(struct nvme_ctrl *ctrl, long timeout)
{
	struct nvme_ns *ns;

	mutex_lock(&ctrl->namespaces_mutex);
	list_for_each_entry(ns, &ctrl->namespaces, list) {
		timeout = blk_mq_freeze_queue_wait_timeout(ns->queue, timeout);
		if (timeout <= 0)
			break;
	}
	mutex_unlock(&ctrl->namespaces_mutex);
}
EXPORT_SYMBOL_GPL(nvme_wait_freeze_timeout);

void nvme_wait_freeze(struct nvme_ctrl *ctrl)
{
	struct nvme_ns *ns;

	mutex_lock(&ctrl->namespaces_mutex);
	list_for_each_entry(ns, &ctrl->namespaces, list)
		blk_mq_freeze_queue_wait(ns->queue);
	mutex_unlock(&ctrl->namespaces_mutex);
}
EXPORT_SYMBOL_GPL(nvme_wait_freeze);

void nvme_start_freeze(struct nvme_ctrl *ctrl)
{
	struct nvme_ns *ns;

	mutex_lock(&ctrl->namespaces_mutex);
	list_for_each_entry(ns, &ctrl->namespaces, list)
		blk_freeze_queue_start(ns->queue);
	mutex_unlock(&ctrl->namespaces_mutex);
}
EXPORT_SYMBOL_GPL(nvme_start_freeze);

void nvme_stop_queues(struct nvme_ctrl *ctrl)
{
	struct nvme_ns *ns;

	mutex_lock(&ctrl->namespaces_mutex);
	list_for_each_entry(ns, &ctrl->namespaces, list)
		blk_mq_quiesce_queue(ns->queue);
	mutex_unlock(&ctrl->namespaces_mutex);
}
EXPORT_SYMBOL_GPL(nvme_stop_queues);

void nvme_start_queues(struct nvme_ctrl *ctrl)
{
	struct nvme_ns *ns;

	mutex_lock(&ctrl->namespaces_mutex);
	list_for_each_entry(ns, &ctrl->namespaces, list)
		blk_mq_unquiesce_queue(ns->queue);
	mutex_unlock(&ctrl->namespaces_mutex);
}
EXPORT_SYMBOL_GPL(nvme_start_queues);

int nvme_reinit_tagset(struct nvme_ctrl *ctrl, struct blk_mq_tag_set *set)
{
	if (!ctrl->ops->reinit_request)
		return 0;

	return blk_mq_tagset_iter(set, set->driver_data,
			ctrl->ops->reinit_request);
}
EXPORT_SYMBOL_GPL(nvme_reinit_tagset);

int __init nvme_core_init(void)
{
	int result = -ENOMEM;

	nvme_wq = alloc_workqueue("nvme-wq",
			WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS, 0);
	if (!nvme_wq)
		goto out;

	nvme_reset_wq = alloc_workqueue("nvme-reset-wq",
			WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS, 0);
	if (!nvme_reset_wq)
		goto destroy_wq;

	nvme_delete_wq = alloc_workqueue("nvme-delete-wq",
			WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS, 0);
	if (!nvme_delete_wq)
		goto destroy_reset_wq;

	result = alloc_chrdev_region(&nvme_chr_devt, 0, NVME_MINORS, "nvme");
	if (result < 0)
		goto destroy_delete_wq;

	nvme_class = class_create(THIS_MODULE, "nvme");
	if (IS_ERR(nvme_class)) {
		result = PTR_ERR(nvme_class);
		goto unregister_chrdev;
	}

	nvme_subsys_class = class_create(THIS_MODULE, "nvme-subsystem");
	if (IS_ERR(nvme_subsys_class)) {
		result = PTR_ERR(nvme_subsys_class);
		goto destroy_class;
	}
	return 0;

destroy_class:
	class_destroy(nvme_class);
unregister_chrdev:
	unregister_chrdev_region(nvme_chr_devt, NVME_MINORS);
destroy_delete_wq:
	destroy_workqueue(nvme_delete_wq);
destroy_reset_wq:
	destroy_workqueue(nvme_reset_wq);
destroy_wq:
	destroy_workqueue(nvme_wq);
out:
	return result;
}

void nvme_core_exit(void)
{
	ida_destroy(&nvme_subsystems_ida);
	class_destroy(nvme_subsys_class);
	class_destroy(nvme_class);
	unregister_chrdev_region(nvme_chr_devt, NVME_MINORS);
	destroy_workqueue(nvme_delete_wq);
	destroy_workqueue(nvme_reset_wq);
	destroy_workqueue(nvme_wq);
}

MODULE_LICENSE("GPL");
MODULE_VERSION("1.0");
module_init(nvme_core_init);
module_exit(nvme_core_exit);