Merge tag 'for-5.18/write-streams-2022-03-18' of git://git.kernel.dk/linux-block

[linux-2.6-microblaze.git] / drivers / nvme / host / core.c

// SPDX-License-Identifier: GPL-2.0
/*
 * NVM Express device driver
 * Copyright (c) 2011-2014, Intel Corporation.
 */

#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/blk-integrity.h>
#include <linux/compat.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/hdreg.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/backing-dev.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/pr.h>
#include <linux/ptrace.h>
#include <linux/nvme_ioctl.h>
#include <linux/pm_qos.h>
#include <asm/unaligned.h>

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

#define CREATE_TRACE_POINTS
#include "trace.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 unsigned long apst_primary_timeout_ms = 100;
module_param(apst_primary_timeout_ms, ulong, 0644);
MODULE_PARM_DESC(apst_primary_timeout_ms,
        "primary APST timeout in ms");

static unsigned long apst_secondary_timeout_ms = 2000;
module_param(apst_secondary_timeout_ms, ulong, 0644);
MODULE_PARM_DESC(apst_secondary_timeout_ms,
        "secondary APST timeout in ms");

static unsigned long apst_primary_latency_tol_us = 15000;
module_param(apst_primary_latency_tol_us, ulong, 0644);
MODULE_PARM_DESC(apst_primary_latency_tol_us,
        "primary APST latency tolerance in us");

static unsigned long apst_secondary_latency_tol_us = 100000;
module_param(apst_secondary_latency_tol_us, ulong, 0644);
MODULE_PARM_DESC(apst_secondary_latency_tol_us,
        "secondary APST latency tolerance in us");

/*
 * 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 as scan, aen handling, fw activation,
 * keep-alive, 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 LIST_HEAD(nvme_subsystems);
static DEFINE_MUTEX(nvme_subsystems_lock);

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

static DEFINE_IDA(nvme_ns_chr_minor_ida);
static dev_t nvme_ns_chr_devt;
static struct class *nvme_ns_chr_class;

static void nvme_put_subsystem(struct nvme_subsystem *subsys);
static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
                                           unsigned nsid);
static void nvme_update_keep_alive(struct nvme_ctrl *ctrl,
                                   struct nvme_command *cmd);

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 && ctrl->tagset)
                queue_work(nvme_wq, &ctrl->scan_work);
}

/*
 * Use this function to proceed with scheduling reset_work for a controller
 * that had previously been set to the resetting state. This is intended for
 * code paths that can't be interrupted by other reset attempts. A hot removal
 * may prevent this from succeeding.
 */
int nvme_try_sched_reset(struct nvme_ctrl *ctrl)
{
        if (ctrl->state != NVME_CTRL_RESETTING)
                return -EBUSY;
        if (!queue_work(nvme_reset_wq, &ctrl->reset_work))
                return -EBUSY;
        return 0;
}
EXPORT_SYMBOL_GPL(nvme_try_sched_reset);

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

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

        set_bit(NVME_CTRL_FAILFAST_EXPIRED, &ctrl->flags);
        dev_info(ctrl->device, "failfast expired\n");
        nvme_kick_requeue_lists(ctrl);
}

static inline void nvme_start_failfast_work(struct nvme_ctrl *ctrl)
{
        if (!ctrl->opts || ctrl->opts->fast_io_fail_tmo == -1)
                return;

        schedule_delayed_work(&ctrl->failfast_work,
                              ctrl->opts->fast_io_fail_tmo * HZ);
}

static inline void nvme_stop_failfast_work(struct nvme_ctrl *ctrl)
{
        if (!ctrl->opts)
                return;

        cancel_delayed_work_sync(&ctrl->failfast_work);
        clear_bit(NVME_CTRL_FAILFAST_EXPIRED, &ctrl->flags);
}


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);
                if (ctrl->state != NVME_CTRL_LIVE)
                        ret = -ENETRESET;
        }

        return ret;
}

static void nvme_do_delete_ctrl(struct nvme_ctrl *ctrl)
{
        dev_info(ctrl->device,
                 "Removing ctrl: NQN \"%s\"\n", nvmf_ctrl_subsysnqn(ctrl));

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

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

        nvme_do_delete_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);

static void nvme_delete_ctrl_sync(struct nvme_ctrl *ctrl)
{
        /*
         * Keep a reference until nvme_do_delete_ctrl() complete,
         * since ->delete_ctrl can free the controller.
         */
        nvme_get_ctrl(ctrl);
        if (nvme_change_ctrl_state(ctrl, NVME_CTRL_DELETING))
                nvme_do_delete_ctrl(ctrl);
        nvme_put_ctrl(ctrl);
}

static blk_status_t nvme_error_status(u16 status)
{
        switch (status & 0x7ff) {
        case NVME_SC_SUCCESS:
                return BLK_STS_OK;
        case NVME_SC_CAP_EXCEEDED:
                return BLK_STS_NOSPC;
        case NVME_SC_LBA_RANGE:
        case NVME_SC_CMD_INTERRUPTED:
        case NVME_SC_NS_NOT_READY:
                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;
        case NVME_SC_HOST_PATH_ERROR:
                return BLK_STS_TRANSPORT;
        case NVME_SC_ZONE_TOO_MANY_ACTIVE:
                return BLK_STS_ZONE_ACTIVE_RESOURCE;
        case NVME_SC_ZONE_TOO_MANY_OPEN:
                return BLK_STS_ZONE_OPEN_RESOURCE;
        default:
                return BLK_STS_IOERR;
        }
}

static void nvme_retry_req(struct request *req)
{
        unsigned long delay = 0;
        u16 crd;

        /* The mask and shift result must be <= 3 */
        crd = (nvme_req(req)->status & NVME_SC_CRD) >> 11;
        if (crd)
                delay = nvme_req(req)->ctrl->crdt[crd - 1] * 100;

        nvme_req(req)->retries++;
        blk_mq_requeue_request(req, false);
        blk_mq_delay_kick_requeue_list(req->q, delay);
}

static void nvme_log_error(struct request *req)
{
        struct nvme_ns *ns = req->q->queuedata;
        struct nvme_request *nr = nvme_req(req);

        if (ns) {
                pr_err_ratelimited("%s: %s(0x%x) @ LBA %llu, %llu blocks, %s (sct 0x%x / sc 0x%x) %s%s\n",
                       ns->disk ? ns->disk->disk_name : "?",
                       nvme_get_opcode_str(nr->cmd->common.opcode),
                       nr->cmd->common.opcode,
                       (unsigned long long)nvme_sect_to_lba(ns, blk_rq_pos(req)),
                       (unsigned long long)blk_rq_bytes(req) >> ns->lba_shift,
                       nvme_get_error_status_str(nr->status),
                       nr->status >> 8 & 7,     /* Status Code Type */
                       nr->status & 0xff,       /* Status Code */
                       nr->status & NVME_SC_MORE ? "MORE " : "",
                       nr->status & NVME_SC_DNR  ? "DNR "  : "");
                return;
        }

        pr_err_ratelimited("%s: %s(0x%x), %s (sct 0x%x / sc 0x%x) %s%s\n",
                           dev_name(nr->ctrl->device),
                           nvme_get_admin_opcode_str(nr->cmd->common.opcode),
                           nr->cmd->common.opcode,
                           nvme_get_error_status_str(nr->status),
                           nr->status >> 8 & 7, /* Status Code Type */
                           nr->status & 0xff,   /* Status Code */
                           nr->status & NVME_SC_MORE ? "MORE " : "",
                           nr->status & NVME_SC_DNR  ? "DNR "  : "");
}

enum nvme_disposition {
        COMPLETE,
        RETRY,
        FAILOVER,
};

static inline enum nvme_disposition nvme_decide_disposition(struct request *req)
{
        if (likely(nvme_req(req)->status == 0))
                return COMPLETE;

        if (blk_noretry_request(req) ||
            (nvme_req(req)->status & NVME_SC_DNR) ||
            nvme_req(req)->retries >= nvme_max_retries)
                return COMPLETE;

        if (req->cmd_flags & REQ_NVME_MPATH) {
                if (nvme_is_path_error(nvme_req(req)->status) ||
                    blk_queue_dying(req->q))
                        return FAILOVER;
        } else {
                if (blk_queue_dying(req->q))
                        return COMPLETE;
        }

        return RETRY;
}

static inline void nvme_end_req_zoned(struct request *req)
{
        if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
            req_op(req) == REQ_OP_ZONE_APPEND)
                req->__sector = nvme_lba_to_sect(req->q->queuedata,
                        le64_to_cpu(nvme_req(req)->result.u64));
}

static inline void nvme_end_req(struct request *req)
{
        blk_status_t status = nvme_error_status(nvme_req(req)->status);

        if (unlikely(nvme_req(req)->status != NVME_SC_SUCCESS))
                nvme_log_error(req);
        nvme_end_req_zoned(req);
        nvme_trace_bio_complete(req);
        blk_mq_end_request(req, status);
}

void nvme_complete_rq(struct request *req)
{
        trace_nvme_complete_rq(req);
        nvme_cleanup_cmd(req);

        if (nvme_req(req)->ctrl->kas)
                nvme_req(req)->ctrl->comp_seen = true;

        switch (nvme_decide_disposition(req)) {
        case COMPLETE:
                nvme_end_req(req);
                return;
        case RETRY:
                nvme_retry_req(req);
                return;
        case FAILOVER:
                nvme_failover_req(req);
                return;
        }
}
EXPORT_SYMBOL_GPL(nvme_complete_rq);

void nvme_complete_batch_req(struct request *req)
{
        trace_nvme_complete_rq(req);
        nvme_cleanup_cmd(req);
        nvme_end_req_zoned(req);
}
EXPORT_SYMBOL_GPL(nvme_complete_batch_req);

/*
 * Called to unwind from ->queue_rq on a failed command submission so that the
 * multipathing code gets called to potentially failover to another path.
 * The caller needs to unwind all transport specific resource allocations and
 * must return propagate the return value.
 */
blk_status_t nvme_host_path_error(struct request *req)
{
        nvme_req(req)->status = NVME_SC_HOST_PATH_ERROR;
        blk_mq_set_request_complete(req);
        nvme_complete_rq(req);
        return BLK_STS_OK;
}
EXPORT_SYMBOL_GPL(nvme_host_path_error);

bool nvme_cancel_request(struct request *req, void *data, bool reserved)
{
        dev_dbg_ratelimited(((struct nvme_ctrl *) data)->device,
                                "Cancelling I/O %d", req->tag);

        /* don't abort one completed request */
        if (blk_mq_request_completed(req))
                return true;

        nvme_req(req)->status = NVME_SC_HOST_ABORTED_CMD;
        nvme_req(req)->flags |= NVME_REQ_CANCELLED;
        blk_mq_complete_request(req);
        return true;
}
EXPORT_SYMBOL_GPL(nvme_cancel_request);

void nvme_cancel_tagset(struct nvme_ctrl *ctrl)
{
        if (ctrl->tagset) {
                blk_mq_tagset_busy_iter(ctrl->tagset,
                                nvme_cancel_request, ctrl);
                blk_mq_tagset_wait_completed_request(ctrl->tagset);
        }
}
EXPORT_SYMBOL_GPL(nvme_cancel_tagset);

void nvme_cancel_admin_tagset(struct nvme_ctrl *ctrl)
{
        if (ctrl->admin_tagset) {
                blk_mq_tagset_busy_iter(ctrl->admin_tagset,
                                nvme_cancel_request, ctrl);
                blk_mq_tagset_wait_completed_request(ctrl->admin_tagset);
        }
}
EXPORT_SYMBOL_GPL(nvme_cancel_admin_tagset);

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_LIVE:
                switch (old_state) {
                case NVME_CTRL_NEW:
                case NVME_CTRL_RESETTING:
                case NVME_CTRL_CONNECTING:
                        changed = true;
                        fallthrough;
                default:
                        break;
                }
                break;
        case NVME_CTRL_RESETTING:
                switch (old_state) {
                case NVME_CTRL_NEW:
                case NVME_CTRL_LIVE:
                        changed = true;
                        fallthrough;
                default:
                        break;
                }
                break;
        case NVME_CTRL_CONNECTING:
                switch (old_state) {
                case NVME_CTRL_NEW:
                case NVME_CTRL_RESETTING:
                        changed = true;
                        fallthrough;
                default:
                        break;
                }
                break;
        case NVME_CTRL_DELETING:
                switch (old_state) {
                case NVME_CTRL_LIVE:
                case NVME_CTRL_RESETTING:
                case NVME_CTRL_CONNECTING:
                        changed = true;
                        fallthrough;
                default:
                        break;
                }
                break;
        case NVME_CTRL_DELETING_NOIO:
                switch (old_state) {
                case NVME_CTRL_DELETING:
                case NVME_CTRL_DEAD:
                        changed = true;
                        fallthrough;
                default:
                        break;
                }
                break;
        case NVME_CTRL_DEAD:
                switch (old_state) {
                case NVME_CTRL_DELETING:
                        changed = true;
                        fallthrough;
                default:
                        break;
                }
                break;
        default:
                break;
        }

        if (changed) {
                ctrl->state = new_state;
                wake_up_all(&ctrl->state_wq);
        }

        spin_unlock_irqrestore(&ctrl->lock, flags);
        if (!changed)
                return false;

        if (ctrl->state == NVME_CTRL_LIVE) {
                if (old_state == NVME_CTRL_CONNECTING)
                        nvme_stop_failfast_work(ctrl);
                nvme_kick_requeue_lists(ctrl);
        } else if (ctrl->state == NVME_CTRL_CONNECTING &&
                old_state == NVME_CTRL_RESETTING) {
                nvme_start_failfast_work(ctrl);
        }
        return changed;
}
EXPORT_SYMBOL_GPL(nvme_change_ctrl_state);

/*
 * Returns true for sink states that can't ever transition back to live.
 */
static bool nvme_state_terminal(struct nvme_ctrl *ctrl)
{
        switch (ctrl->state) {
        case NVME_CTRL_NEW:
        case NVME_CTRL_LIVE:
        case NVME_CTRL_RESETTING:
        case NVME_CTRL_CONNECTING:
                return false;
        case NVME_CTRL_DELETING:
        case NVME_CTRL_DELETING_NOIO:
        case NVME_CTRL_DEAD:
                return true;
        default:
                WARN_ONCE(1, "Unhandled ctrl state:%d", ctrl->state);
                return true;
        }
}

/*
 * Waits for the controller state to be resetting, or returns false if it is
 * not possible to ever transition to that state.
 */
bool nvme_wait_reset(struct nvme_ctrl *ctrl)
{
        wait_event(ctrl->state_wq,
                   nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING) ||
                   nvme_state_terminal(ctrl));
        return ctrl->state == NVME_CTRL_RESETTING;
}
EXPORT_SYMBOL_GPL(nvme_wait_reset);

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_free(&head->subsys->ns_ida, head->instance);
        cleanup_srcu_struct(&head->srcu);
        nvme_put_subsystem(head->subsys);
        kfree(head);
}

bool nvme_tryget_ns_head(struct nvme_ns_head *head)
{
        return kref_get_unless_zero(&head->ref);
}

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);

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

static inline bool nvme_get_ns(struct nvme_ns *ns)
{
        return kref_get_unless_zero(&ns->kref);
}

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

static inline void nvme_clear_nvme_request(struct request *req)
{
        nvme_req(req)->status = 0;
        nvme_req(req)->retries = 0;
        nvme_req(req)->flags = 0;
        req->rq_flags |= RQF_DONTPREP;
}

/* initialize a passthrough request */
void nvme_init_request(struct request *req, struct nvme_command *cmd)
{
        if (req->q->queuedata)
                req->timeout = NVME_IO_TIMEOUT;
        else /* no queuedata implies admin queue */
                req->timeout = NVME_ADMIN_TIMEOUT;

        /* passthru commands should let the driver set the SGL flags */
        cmd->common.flags &= ~NVME_CMD_SGL_ALL;

        req->cmd_flags |= REQ_FAILFAST_DRIVER;
        if (req->mq_hctx->type == HCTX_TYPE_POLL)
                req->cmd_flags |= REQ_POLLED;
        nvme_clear_nvme_request(req);
        memcpy(nvme_req(req)->cmd, cmd, sizeof(*cmd));
}
EXPORT_SYMBOL_GPL(nvme_init_request);

/*
 * For something we're not in a state to send to the device the default action
 * is to busy it and retry it after the controller state is recovered.  However,
 * if the controller is deleting or if anything is marked for failfast or
 * nvme multipath it is immediately failed.
 *
 * Note: commands used to initialize the controller will be marked for failfast.
 * Note: nvme cli/ioctl commands are marked for failfast.
 */
blk_status_t nvme_fail_nonready_command(struct nvme_ctrl *ctrl,
                struct request *rq)
{
        if (ctrl->state != NVME_CTRL_DELETING_NOIO &&
            ctrl->state != NVME_CTRL_DELETING &&
            ctrl->state != NVME_CTRL_DEAD &&
            !test_bit(NVME_CTRL_FAILFAST_EXPIRED, &ctrl->flags) &&
            !blk_noretry_request(rq) && !(rq->cmd_flags & REQ_NVME_MPATH))
                return BLK_STS_RESOURCE;
        return nvme_host_path_error(rq);
}
EXPORT_SYMBOL_GPL(nvme_fail_nonready_command);

bool __nvme_check_ready(struct nvme_ctrl *ctrl, struct request *rq,
                bool queue_live)
{
        struct nvme_request *req = nvme_req(rq);

        /*
         * currently we have a problem sending passthru commands
         * on the admin_q if the controller is not LIVE because we can't
         * make sure that they are going out after the admin connect,
         * controller enable and/or other commands in the initialization
         * sequence. until the controller will be LIVE, fail with
         * BLK_STS_RESOURCE so that they will be rescheduled.
         */
        if (rq->q == ctrl->admin_q && (req->flags & NVME_REQ_USERCMD))
                return false;

        if (ctrl->ops->flags & NVME_F_FABRICS) {
                /*
                 * Only allow commands on a live queue, except for the connect
                 * command, which is require to set the queue live in the
                 * appropinquate states.
                 */
                switch (ctrl->state) {
                case NVME_CTRL_CONNECTING:
                        if (blk_rq_is_passthrough(rq) && nvme_is_fabrics(req->cmd) &&
                            req->cmd->fabrics.fctype == nvme_fabrics_type_connect)
                                return true;
                        break;
                default:
                        break;
                case NVME_CTRL_DEAD:
                        return false;
                }
        }

        return queue_live;
}
EXPORT_SYMBOL_GPL(__nvme_check_ready);

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;

        /*
         * Some devices do not consider the DSM 'Number of Ranges' field when
         * determining how much data to DMA. Always allocate memory for maximum
         * number of segments to prevent device reading beyond end of buffer.
         */
        static const size_t alloc_size = sizeof(*range) * NVME_DSM_MAX_RANGES;

        range = kzalloc(alloc_size, GFP_ATOMIC | __GFP_NOWARN);
        if (!range) {
                /*
                 * If we fail allocation our range, fallback to the controller
                 * discard page. If that's also busy, it's safe to return
                 * busy, as we know we can make progress once that's freed.
                 */
                if (test_and_set_bit_lock(0, &ns->ctrl->discard_page_busy))
                        return BLK_STS_RESOURCE;

                range = page_address(ns->ctrl->discard_page);
        }

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

                if (n < segments) {
                        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)) {
                if (virt_to_page(range) == ns->ctrl->discard_page)
                        clear_bit_unlock(0, &ns->ctrl->discard_page_busy);
                else
                        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 = alloc_size;
        req->rq_flags |= RQF_SPECIAL_PAYLOAD;

        return BLK_STS_OK;
}

static inline blk_status_t nvme_setup_write_zeroes(struct nvme_ns *ns,
                struct request *req, struct nvme_command *cmnd)
{
        memset(cmnd, 0, sizeof(*cmnd));

        if (ns->ctrl->quirks & NVME_QUIRK_DEALLOCATE_ZEROES)
                return nvme_setup_discard(ns, req, cmnd);

        cmnd->write_zeroes.opcode = nvme_cmd_write_zeroes;
        cmnd->write_zeroes.nsid = cpu_to_le32(ns->head->ns_id);
        cmnd->write_zeroes.slba =
                cpu_to_le64(nvme_sect_to_lba(ns, blk_rq_pos(req)));
        cmnd->write_zeroes.length =
                cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);

        if (nvme_ns_has_pi(ns)) {
                cmnd->write_zeroes.control = cpu_to_le16(NVME_RW_PRINFO_PRACT);

                switch (ns->pi_type) {
                case NVME_NS_DPS_PI_TYPE1:
                case NVME_NS_DPS_PI_TYPE2:
                        cmnd->write_zeroes.reftag =
                                cpu_to_le32(t10_pi_ref_tag(req));
                        break;
                }
        }

        return BLK_STS_OK;
}

static inline blk_status_t nvme_setup_rw(struct nvme_ns *ns,
                struct request *req, struct nvme_command *cmnd,
                enum nvme_opcode op)
{
        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;

        cmnd->rw.opcode = op;
        cmnd->rw.flags = 0;
        cmnd->rw.nsid = cpu_to_le32(ns->head->ns_id);
        cmnd->rw.rsvd2 = 0;
        cmnd->rw.metadata = 0;
        cmnd->rw.slba = cpu_to_le64(nvme_sect_to_lba(ns, blk_rq_pos(req)));
        cmnd->rw.length = cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);
        cmnd->rw.reftag = 0;
        cmnd->rw.apptag = 0;
        cmnd->rw.appmask = 0;

        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;
                        if (op == nvme_cmd_zone_append)
                                control |= NVME_RW_APPEND_PIREMAP;
                        cmnd->rw.reftag = cpu_to_le32(t10_pi_ref_tag(req));
                        break;
                }
        }

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

void nvme_cleanup_cmd(struct request *req)
{
        if (req->rq_flags & RQF_SPECIAL_PAYLOAD) {
                struct nvme_ctrl *ctrl = nvme_req(req)->ctrl;

                if (req->special_vec.bv_page == ctrl->discard_page)
                        clear_bit_unlock(0, &ctrl->discard_page_busy);
                else
                        kfree(bvec_virt(&req->special_vec));
        }
}
EXPORT_SYMBOL_GPL(nvme_cleanup_cmd);

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

        if (!(req->rq_flags & RQF_DONTPREP))
                nvme_clear_nvme_request(req);

        switch (req_op(req)) {
        case REQ_OP_DRV_IN:
        case REQ_OP_DRV_OUT:
                /* these are setup prior to execution in nvme_init_request() */
                break;
        case REQ_OP_FLUSH:
                nvme_setup_flush(ns, cmd);
                break;
        case REQ_OP_ZONE_RESET_ALL:
        case REQ_OP_ZONE_RESET:
                ret = nvme_setup_zone_mgmt_send(ns, req, cmd, NVME_ZONE_RESET);
                break;
        case REQ_OP_ZONE_OPEN:
                ret = nvme_setup_zone_mgmt_send(ns, req, cmd, NVME_ZONE_OPEN);
                break;
        case REQ_OP_ZONE_CLOSE:
                ret = nvme_setup_zone_mgmt_send(ns, req, cmd, NVME_ZONE_CLOSE);
                break;
        case REQ_OP_ZONE_FINISH:
                ret = nvme_setup_zone_mgmt_send(ns, req, cmd, NVME_ZONE_FINISH);
                break;
        case REQ_OP_WRITE_ZEROES:
                ret = nvme_setup_write_zeroes(ns, req, cmd);
                break;
        case REQ_OP_DISCARD:
                ret = nvme_setup_discard(ns, req, cmd);
                break;
        case REQ_OP_READ:
                ret = nvme_setup_rw(ns, req, cmd, nvme_cmd_read);
                break;
        case REQ_OP_WRITE:
                ret = nvme_setup_rw(ns, req, cmd, nvme_cmd_write);
                break;
        case REQ_OP_ZONE_APPEND:
                ret = nvme_setup_rw(ns, req, cmd, nvme_cmd_zone_append);
                break;
        default:
                WARN_ON_ONCE(1);
                return BLK_STS_IOERR;
        }

        cmd->common.command_id = nvme_cid(req);
        trace_nvme_setup_cmd(req, cmd);
        return ret;
}
EXPORT_SYMBOL_GPL(nvme_setup_cmd);

/*
 * Return values:
 * 0:  success
 * >0: nvme controller's cqe status response
 * <0: kernel error in lieu of controller response
 */
static int nvme_execute_rq(struct request *rq, bool at_head)
{
        blk_status_t status;

        status = blk_execute_rq(rq, at_head);
        if (nvme_req(rq)->flags & NVME_REQ_CANCELLED)
                return -EINTR;
        if (nvme_req(rq)->status)
                return nvme_req(rq)->status;
        return blk_status_to_errno(status);
}

/*
 * 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;

        if (qid == NVME_QID_ANY)
                req = blk_mq_alloc_request(q, nvme_req_op(cmd), flags);
        else
                req = blk_mq_alloc_request_hctx(q, nvme_req_op(cmd), flags,
                                                qid ? qid - 1 : 0);

        if (IS_ERR(req))
                return PTR_ERR(req);
        nvme_init_request(req, cmd);

        if (timeout)
                req->timeout = timeout;

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

        ret = nvme_execute_rq(req, at_head);
        if (result && ret >= 0)
                *result = nvme_req(req)->result;
 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 u32 nvme_known_admin_effects(u8 opcode)
{
        switch (opcode) {
        case nvme_admin_format_nvm:
                return NVME_CMD_EFFECTS_LBCC | NVME_CMD_EFFECTS_NCC |
                        NVME_CMD_EFFECTS_CSE_MASK;
        case nvme_admin_sanitize_nvm:
                return NVME_CMD_EFFECTS_LBCC | NVME_CMD_EFFECTS_CSE_MASK;
        default:
                break;
        }
        return 0;
}

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

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

        if (ctrl->effects)
                effects = le32_to_cpu(ctrl->effects->acs[opcode]);
        effects |= nvme_known_admin_effects(opcode);

        return effects;
}
EXPORT_SYMBOL_NS_GPL(nvme_command_effects, NVME_TARGET_PASSTHRU);

static u32 nvme_passthru_start(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
                               u8 opcode)
{
        u32 effects = nvme_command_effects(ctrl, ns, 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_CSE_MASK) {
                mutex_lock(&ctrl->scan_lock);
                mutex_lock(&ctrl->subsys->lock);
                nvme_mpath_start_freeze(ctrl->subsys);
                nvme_mpath_wait_freeze(ctrl->subsys);
                nvme_start_freeze(ctrl);
                nvme_wait_freeze(ctrl);
        }
        return effects;
}

static void nvme_passthru_end(struct nvme_ctrl *ctrl, u32 effects,
                              struct nvme_command *cmd, int status)
{
        if (effects & NVME_CMD_EFFECTS_CSE_MASK) {
                nvme_unfreeze(ctrl);
                nvme_mpath_unfreeze(ctrl->subsys);
                mutex_unlock(&ctrl->subsys->lock);
                nvme_remove_invalid_namespaces(ctrl, NVME_NSID_ALL);
                mutex_unlock(&ctrl->scan_lock);
        }
        if (effects & NVME_CMD_EFFECTS_CCC)
                nvme_init_ctrl_finish(ctrl);
        if (effects & (NVME_CMD_EFFECTS_NIC | NVME_CMD_EFFECTS_NCC)) {
                nvme_queue_scan(ctrl);
                flush_work(&ctrl->scan_work);
        }

        switch (cmd->common.opcode) {
        case nvme_admin_set_features:
                switch (le32_to_cpu(cmd->common.cdw10) & 0xFF) {
                case NVME_FEAT_KATO:
                        /*
                         * Keep alive commands interval on the host should be
                         * updated when KATO is modified by Set Features
                         * commands.
                         */
                        if (!status)
                                nvme_update_keep_alive(ctrl, cmd);
                        break;
                default:
                        break;
                }
                break;
        default:
                break;
        }
}

int nvme_execute_passthru_rq(struct request *rq)
{
        struct nvme_command *cmd = nvme_req(rq)->cmd;
        struct nvme_ctrl *ctrl = nvme_req(rq)->ctrl;
        struct nvme_ns *ns = rq->q->queuedata;
        u32 effects;
        int  ret;

        effects = nvme_passthru_start(ctrl, ns, cmd->common.opcode);
        ret = nvme_execute_rq(rq, false);
        if (effects) /* nothing to be done for zero cmd effects */
                nvme_passthru_end(ctrl, effects, cmd, ret);

        return ret;
}
EXPORT_SYMBOL_NS_GPL(nvme_execute_passthru_rq, NVME_TARGET_PASSTHRU);

/*
 * Recommended frequency for KATO commands per NVMe 1.4 section 7.12.1:
 * 
 *   The host should send Keep Alive commands at half of the Keep Alive Timeout
 *   accounting for transport roundtrip times [..].
 */
static void nvme_queue_keep_alive_work(struct nvme_ctrl *ctrl)
{
        queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ / 2);
}

static void nvme_keep_alive_end_io(struct request *rq, blk_status_t status)
{
        struct nvme_ctrl *ctrl = rq->end_io_data;
        unsigned long flags;
        bool startka = false;

        blk_mq_free_request(rq);

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

        ctrl->comp_seen = false;
        spin_lock_irqsave(&ctrl->lock, flags);
        if (ctrl->state == NVME_CTRL_LIVE ||
            ctrl->state == NVME_CTRL_CONNECTING)
                startka = true;
        spin_unlock_irqrestore(&ctrl->lock, flags);
        if (startka)
                nvme_queue_keep_alive_work(ctrl);
}

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);
        bool comp_seen = ctrl->comp_seen;
        struct request *rq;

        if ((ctrl->ctratt & NVME_CTRL_ATTR_TBKAS) && comp_seen) {
                dev_dbg(ctrl->device,
                        "reschedule traffic based keep-alive timer\n");
                ctrl->comp_seen = false;
                nvme_queue_keep_alive_work(ctrl);
                return;
        }

        rq = blk_mq_alloc_request(ctrl->admin_q, nvme_req_op(&ctrl->ka_cmd),
                                  BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT);
        if (IS_ERR(rq)) {
                /* allocation failure, reset the controller */
                dev_err(ctrl->device, "keep-alive failed: %ld\n", PTR_ERR(rq));
                nvme_reset_ctrl(ctrl);
                return;
        }
        nvme_init_request(rq, &ctrl->ka_cmd);

        rq->timeout = ctrl->kato * HZ;
        rq->end_io_data = ctrl;
        blk_execute_rq_nowait(rq, false, nvme_keep_alive_end_io);
}

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

        nvme_queue_keep_alive_work(ctrl);
}

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 void nvme_update_keep_alive(struct nvme_ctrl *ctrl,
                                   struct nvme_command *cmd)
{
        unsigned int new_kato =
                DIV_ROUND_UP(le32_to_cpu(cmd->common.cdw11), 1000);

        dev_info(ctrl->device,
                 "keep alive interval updated from %u ms to %u ms\n",
                 ctrl->kato * 1000 / 2, new_kato * 1000 / 2);

        nvme_stop_keep_alive(ctrl);
        ctrl->kato = new_kato;
        nvme_start_keep_alive(ctrl);
}

/*
 * In NVMe 1.0 the CNS field was just a binary controller or namespace
 * flag, thus sending any new CNS opcodes has a big chance of not working.
 * Qemu unfortunately had that bug after reporting a 1.1 version compliance
 * (but not for any later version).
 */
static bool nvme_ctrl_limited_cns(struct nvme_ctrl *ctrl)
{
        if (ctrl->quirks & NVME_QUIRK_IDENTIFY_CNS)
                return ctrl->vs < NVME_VS(1, 2, 0);
        return ctrl->vs < NVME_VS(1, 1, 0);
}

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_process_ns_desc(struct nvme_ctrl *ctrl, struct nvme_ns_ids *ids,
                struct nvme_ns_id_desc *cur, bool *csi_seen)
{
        const char *warn_str = "ctrl returned bogus length:";
        void *data = cur;

        switch (cur->nidt) {
        case NVME_NIDT_EUI64:
                if (cur->nidl != NVME_NIDT_EUI64_LEN) {
                        dev_warn(ctrl->device, "%s %d for NVME_NIDT_EUI64\n",
                                 warn_str, cur->nidl);
                        return -1;
                }
                memcpy(ids->eui64, data + sizeof(*cur), NVME_NIDT_EUI64_LEN);
                return NVME_NIDT_EUI64_LEN;
        case NVME_NIDT_NGUID:
                if (cur->nidl != NVME_NIDT_NGUID_LEN) {
                        dev_warn(ctrl->device, "%s %d for NVME_NIDT_NGUID\n",
                                 warn_str, cur->nidl);
                        return -1;
                }
                memcpy(ids->nguid, data + sizeof(*cur), NVME_NIDT_NGUID_LEN);
                return NVME_NIDT_NGUID_LEN;
        case NVME_NIDT_UUID:
                if (cur->nidl != NVME_NIDT_UUID_LEN) {
                        dev_warn(ctrl->device, "%s %d for NVME_NIDT_UUID\n",
                                 warn_str, cur->nidl);
                        return -1;
                }
                uuid_copy(&ids->uuid, data + sizeof(*cur));
                return NVME_NIDT_UUID_LEN;
        case NVME_NIDT_CSI:
                if (cur->nidl != NVME_NIDT_CSI_LEN) {
                        dev_warn(ctrl->device, "%s %d for NVME_NIDT_CSI\n",
                                 warn_str, cur->nidl);
                        return -1;
                }
                memcpy(&ids->csi, data + sizeof(*cur), NVME_NIDT_CSI_LEN);
                *csi_seen = true;
                return NVME_NIDT_CSI_LEN;
        default:
                /* Skip unknown types */
                return cur->nidl;
        }
}

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

        if (ctrl->vs < NVME_VS(1, 3, 0) && !nvme_multi_css(ctrl))
                return 0;
        if (ctrl->quirks & NVME_QUIRK_NO_NS_DESC_LIST)
                return 0;

        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) {
                dev_warn(ctrl->device,
                        "Identify Descriptors failed (nsid=%u, status=0x%x)\n",
                        nsid, 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;

                len = nvme_process_ns_desc(ctrl, ids, cur, &csi_seen);
                if (len < 0)
                        break;

                len += sizeof(*cur);
        }

        if (nvme_multi_css(ctrl) && !csi_seen) {
                dev_warn(ctrl->device, "Command set not reported for nsid:%d\n",
                         nsid);
                status = -EINVAL;
        }

free_data:
        kfree(data);
        return status;
}

static int nvme_identify_ns(struct nvme_ctrl *ctrl, unsigned nsid,
                        struct nvme_ns_ids *ids, 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 -ENOMEM;

        error = nvme_submit_sync_cmd(ctrl->admin_q, &c, *id, sizeof(**id));
        if (error) {
                dev_warn(ctrl->device, "Identify namespace failed (%d)\n", error);
                goto out_free_id;
        }

        error = NVME_SC_INVALID_NS | NVME_SC_DNR;
        if ((*id)->ncap == 0) /* namespace not allocated or attached */
                goto out_free_id;

        if (ctrl->vs >= NVME_VS(1, 1, 0) &&
            !memchr_inv(ids->eui64, 0, sizeof(ids->eui64)))
                memcpy(ids->eui64, (*id)->eui64, sizeof(ids->eui64));
        if (ctrl->vs >= NVME_VS(1, 2, 0) &&
            !memchr_inv(ids->nguid, 0, sizeof(ids->nguid)))
                memcpy(ids->nguid, (*id)->nguid, sizeof(ids->nguid));

        return 0;

out_free_id:
        kfree(*id);
        return error;
}

static int nvme_features(struct nvme_ctrl *dev, u8 op, unsigned int fid,
                unsigned int dword11, void *buffer, size_t buflen, u32 *result)
{
        union nvme_result res = { 0 };
        struct nvme_command c = { };
        int ret;

        c.features.opcode = op;
        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_features(struct nvme_ctrl *dev, unsigned int fid,
                      unsigned int dword11, void *buffer, size_t buflen,
                      u32 *result)
{
        return nvme_features(dev, nvme_admin_set_features, fid, dword11, buffer,
                             buflen, result);
}
EXPORT_SYMBOL_GPL(nvme_set_features);

int nvme_get_features(struct nvme_ctrl *dev, unsigned int fid,
                      unsigned int dword11, void *buffer, size_t buflen,
                      u32 *result)
{
        return nvme_features(dev, nvme_admin_get_features, fid, dword11, buffer,
                             buflen, result);
}
EXPORT_SYMBOL_GPL(nvme_get_features);

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);

#define NVME_AEN_SUPPORTED \
        (NVME_AEN_CFG_NS_ATTR | NVME_AEN_CFG_FW_ACT | \
         NVME_AEN_CFG_ANA_CHANGE | NVME_AEN_CFG_DISC_CHANGE)

static void nvme_enable_aen(struct nvme_ctrl *ctrl)
{
        u32 result, supported_aens = ctrl->oaes & NVME_AEN_SUPPORTED;
        int status;

        if (!supported_aens)
                return;

        status = nvme_set_features(ctrl, NVME_FEAT_ASYNC_EVENT, supported_aens,
                        NULL, 0, &result);
        if (status)
                dev_warn(ctrl->device, "Failed to configure AEN (cfg %x)\n",
                         supported_aens);

        queue_work(nvme_wq, &ctrl->async_event_work);
}

static int nvme_ns_open(struct nvme_ns *ns)
{

        /* should never be called due to GENHD_FL_HIDDEN */
        if (WARN_ON_ONCE(nvme_ns_head_multipath(ns->head)))
                goto fail;
        if (!nvme_get_ns(ns))
                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_ns_release(struct nvme_ns *ns)
{

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

static int nvme_open(struct block_device *bdev, fmode_t mode)
{
        return nvme_ns_open(bdev->bd_disk->private_data);
}

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

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,
                                u32 max_integrity_segments)
{
        struct blk_integrity 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, max_integrity_segments);
}
#else
static void nvme_init_integrity(struct gendisk *disk, u16 ms, u8 pi_type,
                                u32 max_integrity_segments)
{
}
#endif /* CONFIG_BLK_DEV_INTEGRITY */

static void nvme_config_discard(struct gendisk *disk, struct nvme_ns *ns)
{
        struct nvme_ctrl *ctrl = ns->ctrl;
        struct request_queue *queue = disk->queue;
        u32 size = queue_logical_block_size(queue);

        if (ctrl->max_discard_sectors == 0) {
                blk_queue_flag_clear(QUEUE_FLAG_DISCARD, queue);
                return;
        }

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

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

        /* If discard is already enabled, don't reset queue limits */
        if (blk_queue_flag_test_and_set(QUEUE_FLAG_DISCARD, queue))
                return;

        blk_queue_max_discard_sectors(queue, ctrl->max_discard_sectors);
        blk_queue_max_discard_segments(queue, ctrl->max_discard_segments);

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

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 &&
                a->csi == b->csi;
}

static void nvme_configure_metadata(struct nvme_ns *ns, struct nvme_id_ns *id)
{
        struct nvme_ctrl *ctrl = ns->ctrl;

        /*
         * The PI implementation requires the metadata size to be equal to the
         * t10 pi tuple size.
         */
        ns->ms = le16_to_cpu(id->lbaf[id->flbas & NVME_NS_FLBAS_LBA_MASK].ms);
        if (ns->ms == sizeof(struct t10_pi_tuple))
                ns->pi_type = id->dps & NVME_NS_DPS_PI_MASK;
        else
                ns->pi_type = 0;

        ns->features &= ~(NVME_NS_METADATA_SUPPORTED | NVME_NS_EXT_LBAS);
        if (!ns->ms || !(ctrl->ops->flags & NVME_F_METADATA_SUPPORTED))
                return;

        if (ctrl->ops->flags & NVME_F_FABRICS) {
                /*
                 * The NVMe over Fabrics specification only supports metadata as
                 * part of the extended data LBA.  We rely on HCA/HBA support to
                 * remap the separate metadata buffer from the block layer.
                 */
                if (WARN_ON_ONCE(!(id->flbas & NVME_NS_FLBAS_META_EXT)))
                        return;

                ns->features |= NVME_NS_EXT_LBAS;

                /*
                 * The current fabrics transport drivers support namespace
                 * metadata formats only if nvme_ns_has_pi() returns true.
                 * Suppress support for all other formats so the namespace will
                 * have a 0 capacity and not be usable through the block stack.
                 *
                 * Note, this check will need to be modified if any drivers
                 * gain the ability to use other metadata formats.
                 */
                if (ctrl->max_integrity_segments && nvme_ns_has_pi(ns))
                        ns->features |= NVME_NS_METADATA_SUPPORTED;
        } else {
                /*
                 * For PCIe controllers, we can't easily remap the separate
                 * metadata buffer from the block layer and thus require a
                 * separate metadata buffer for block layer metadata/PI support.
                 * We allow extended LBAs for the passthrough interface, though.
                 */
                if (id->flbas & NVME_NS_FLBAS_META_EXT)
                        ns->features |= NVME_NS_EXT_LBAS;
                else
                        ns->features |= NVME_NS_METADATA_SUPPORTED;
        }
}

static void nvme_set_queue_limits(struct nvme_ctrl *ctrl,
                struct request_queue *q)
{
        bool vwc = ctrl->vwc & NVME_CTRL_VWC_PRESENT;

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

                max_segments = min_not_zero(max_segments, ctrl->max_segments);
                blk_queue_max_hw_sectors(q, ctrl->max_hw_sectors);
                blk_queue_max_segments(q, min_t(u32, max_segments, USHRT_MAX));
        }
        blk_queue_virt_boundary(q, NVME_CTRL_PAGE_SIZE - 1);
        blk_queue_dma_alignment(q, 7);
        blk_queue_write_cache(q, vwc, vwc);
}

static void nvme_update_disk_info(struct gendisk *disk,
                struct nvme_ns *ns, struct nvme_id_ns *id)
{
        sector_t capacity = nvme_lba_to_sect(ns, le64_to_cpu(id->nsze));
        unsigned short bs = 1 << ns->lba_shift;
        u32 atomic_bs, phys_bs, io_opt = 0;

        /*
         * The block layer can't support LBA sizes larger than the page size
         * yet, so catch this early and don't allow block I/O.
         */
        if (ns->lba_shift > PAGE_SHIFT) {
                capacity = 0;
                bs = (1 << 9);
        }

        blk_integrity_unregister(disk);

        atomic_bs = phys_bs = bs;
        if (id->nabo == 0) {
                /*
                 * Bit 1 indicates whether NAWUPF is defined for this namespace
                 * and whether it should be used instead of AWUPF. If NAWUPF ==
                 * 0 then AWUPF must be used instead.
                 */
                if (id->nsfeat & NVME_NS_FEAT_ATOMICS && id->nawupf)
                        atomic_bs = (1 + le16_to_cpu(id->nawupf)) * bs;
                else
                        atomic_bs = (1 + ns->ctrl->subsys->awupf) * bs;
        }

        if (id->nsfeat & NVME_NS_FEAT_IO_OPT) {
                /* NPWG = Namespace Preferred Write Granularity */
                phys_bs = bs * (1 + le16_to_cpu(id->npwg));
                /* NOWS = Namespace Optimal Write Size */
                io_opt = bs * (1 + le16_to_cpu(id->nows));
        }

        blk_queue_logical_block_size(disk->queue, bs);
        /*
         * Linux filesystems assume writing a single physical block is
         * an atomic operation. Hence limit the physical block size to the
         * value of the Atomic Write Unit Power Fail parameter.
         */
        blk_queue_physical_block_size(disk->queue, min(phys_bs, atomic_bs));
        blk_queue_io_min(disk->queue, phys_bs);
        blk_queue_io_opt(disk->queue, io_opt);

        /*
         * Register a metadata profile for PI, or the plain non-integrity NVMe
         * metadata masquerading as Type 0 if supported, otherwise reject block
         * I/O to namespaces with metadata except when the namespace supports
         * PI, as it can strip/insert in that case.
         */
        if (ns->ms) {
                if (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY) &&
                    (ns->features & NVME_NS_METADATA_SUPPORTED))
                        nvme_init_integrity(disk, ns->ms, ns->pi_type,
                                            ns->ctrl->max_integrity_segments);
                else if (!nvme_ns_has_pi(ns))
                        capacity = 0;
        }

        set_capacity_and_notify(disk, capacity);

        nvme_config_discard(disk, ns);
        blk_queue_max_write_zeroes_sectors(disk->queue,
                                           ns->ctrl->max_zeroes_sectors);

        set_disk_ro(disk, (id->nsattr & NVME_NS_ATTR_RO) ||
                test_bit(NVME_NS_FORCE_RO, &ns->flags));
}

static inline bool nvme_first_scan(struct gendisk *disk)
{
        /* nvme_alloc_ns() scans the disk prior to adding it */
        return !disk_live(disk);
}

static void nvme_set_chunk_sectors(struct nvme_ns *ns, struct nvme_id_ns *id)
{
        struct nvme_ctrl *ctrl = ns->ctrl;
        u32 iob;

        if ((ctrl->quirks & NVME_QUIRK_STRIPE_SIZE) &&
            is_power_of_2(ctrl->max_hw_sectors))
                iob = ctrl->max_hw_sectors;
        else
                iob = nvme_lba_to_sect(ns, le16_to_cpu(id->noiob));

        if (!iob)
                return;

        if (!is_power_of_2(iob)) {
                if (nvme_first_scan(ns->disk))
                        pr_warn("%s: ignoring unaligned IO boundary:%u\n",
                                ns->disk->disk_name, iob);
                return;
        }

        if (blk_queue_is_zoned(ns->disk->queue)) {
                if (nvme_first_scan(ns->disk))
                        pr_warn("%s: ignoring zoned namespace IO boundary\n",
                                ns->disk->disk_name);
                return;
        }

        blk_queue_chunk_sectors(ns->queue, iob);
}

static int nvme_update_ns_info(struct nvme_ns *ns, struct nvme_id_ns *id)
{
        unsigned lbaf = id->flbas & NVME_NS_FLBAS_LBA_MASK;
        int ret;

        blk_mq_freeze_queue(ns->disk->queue);
        ns->lba_shift = id->lbaf[lbaf].ds;
        nvme_set_queue_limits(ns->ctrl, ns->queue);

        nvme_configure_metadata(ns, id);
        nvme_set_chunk_sectors(ns, id);
        nvme_update_disk_info(ns->disk, ns, id);

        if (ns->head->ids.csi == NVME_CSI_ZNS) {
                ret = nvme_update_zone_info(ns, lbaf);
                if (ret)
                        goto out_unfreeze;
        }

        set_bit(NVME_NS_READY, &ns->flags);
        blk_mq_unfreeze_queue(ns->disk->queue);

        if (blk_queue_is_zoned(ns->queue)) {
                ret = nvme_revalidate_zones(ns);
                if (ret && !nvme_first_scan(ns->disk))
                        return ret;
        }

        if (nvme_ns_head_multipath(ns->head)) {
                blk_mq_freeze_queue(ns->head->disk->queue);
                nvme_update_disk_info(ns->head->disk, ns, id);
                nvme_mpath_revalidate_paths(ns);
                blk_stack_limits(&ns->head->disk->queue->limits,
                                 &ns->queue->limits, 0);
                disk_update_readahead(ns->head->disk);
                blk_mq_unfreeze_queue(ns->head->disk->queue);
        }
        return 0;

out_unfreeze:
        /*
         * If probing fails due an unsupported feature, hide the block device,
         * but still allow other access.
         */
        if (ret == -ENODEV) {
                ns->disk->flags |= GENHD_FL_HIDDEN;
                set_bit(NVME_NS_READY, &ns->flags);
                ret = 0;
        }
        blk_mq_unfreeze_queue(ns->disk->queue);
        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_send_ns_head_pr_command(struct block_device *bdev,
                struct nvme_command *c, u8 data[16])
{
        struct nvme_ns_head *head = bdev->bd_disk->private_data;
        int srcu_idx = srcu_read_lock(&head->srcu);
        struct nvme_ns *ns = nvme_find_path(head);
        int ret = -EWOULDBLOCK;

        if (ns) {
                c->common.nsid = cpu_to_le32(ns->head->ns_id);
                ret = nvme_submit_sync_cmd(ns->queue, c, data, 16);
        }
        srcu_read_unlock(&head->srcu, srcu_idx);
        return ret;
}
        
static int nvme_send_ns_pr_command(struct nvme_ns *ns, struct nvme_command *c,
                u8 data[16])
{
        c->common.nsid = cpu_to_le32(ns->head->ns_id);
        return nvme_submit_sync_cmd(ns->queue, c, data, 16);
}

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

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

        c.common.opcode = op;
        c.common.cdw10 = cpu_to_le32(cdw10);

        if (IS_ENABLED(CONFIG_NVME_MULTIPATH) &&
            bdev->bd_disk->fops == &nvme_ns_head_ops)
                return nvme_send_ns_head_pr_command(bdev, &c, data);
        return nvme_send_ns_pr_command(bdev->bd_disk->private_data, &c, data);
}

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);
}

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 = { };

        if (send)
                cmd.common.opcode = nvme_admin_security_send;
        else
                cmd.common.opcode = nvme_admin_security_recv;
        cmd.common.nsid = 0;
        cmd.common.cdw10 = cpu_to_le32(((u32)secp) << 24 | ((u32)spsp) << 8);
        cmd.common.cdw11 = cpu_to_le32(len);

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

#ifdef CONFIG_BLK_DEV_ZONED
static int nvme_report_zones(struct gendisk *disk, sector_t sector,
                unsigned int nr_zones, report_zones_cb cb, void *data)
{
        return nvme_ns_report_zones(disk->private_data, sector, nr_zones, cb,
                        data);
}
#else
#define nvme_report_zones       NULL
#endif /* CONFIG_BLK_DEV_ZONED */

static const struct block_device_operations nvme_bdev_ops = {
        .owner          = THIS_MODULE,
        .ioctl          = nvme_ioctl,
        .open           = nvme_open,
        .release        = nvme_release,
        .getgeo         = nvme_getgeo,
        .report_zones   = nvme_report_zones,
        .pr_ops         = &nvme_pr_ops,
};

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;

                usleep_range(1000, 2000);
                if (fatal_signal_pending(current))
                        return -EINTR;
                if (time_after(jiffies, timeout)) {
                        dev_err(ctrl->device,
                                "Device not ready; aborting %s, CSTS=0x%x\n",
                                enabled ? "initialisation" : "reset", csts);
                        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)
{
        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, ctrl->cap, false);
}
EXPORT_SYMBOL_GPL(nvme_disable_ctrl);

int nvme_enable_ctrl(struct nvme_ctrl *ctrl)
{
        unsigned dev_page_min;
        int ret;

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

        if (NVME_CTRL_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 << NVME_CTRL_PAGE_SHIFT);
                return -ENODEV;
        }

        if (NVME_CAP_CSS(ctrl->cap) & NVME_CAP_CSS_CSI)
                ctrl->ctrl_config = NVME_CC_CSS_CSI;
        else
                ctrl->ctrl_config = NVME_CC_CSS_NVM;
        ctrl->ctrl_config |= (NVME_CTRL_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, 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 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_acre(struct nvme_ctrl *ctrl)
{
        struct nvme_feat_host_behavior *host;
        int ret;

        /* Don't bother enabling the feature if retry delay is not reported */
        if (!ctrl->crdt[0])
                return 0;

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

        host->acre = NVME_ENABLE_ACRE;
        ret = nvme_set_features(ctrl, NVME_FEAT_HOST_BEHAVIOR, 0,
                                host, sizeof(*host), NULL);
        kfree(host);
        return ret;
}

/*
 * The function checks whether the given total (exlat + enlat) latency of
 * a power state allows the latter to be used as an APST transition target.
 * It does so by comparing the latency to the primary and secondary latency
 * tolerances defined by module params. If there's a match, the corresponding
 * timeout value is returned and the matching tolerance index (1 or 2) is
 * reported.
 */
static bool nvme_apst_get_transition_time(u64 total_latency,
                u64 *transition_time, unsigned *last_index)
{
        if (total_latency <= apst_primary_latency_tol_us) {
                if (*last_index == 1)
                        return false;
                *last_index = 1;
                *transition_time = apst_primary_timeout_ms;
                return true;
        }
        if (apst_secondary_timeout_ms &&
                total_latency <= apst_secondary_latency_tol_us) {
                if (*last_index <= 2)
                        return false;
                *last_index = 2;
                *transition_time = apst_secondary_timeout_ms;
                return true;
        }
        return false;
}

/*
 * APST (Autonomous Power State Transition) lets us program a table of power
 * state transitions that the controller will perform automatically.
 *
 * Depending on module params, one of the two supported techniques will be used:
 *
 * - If the parameters provide explicit timeouts and tolerances, they will be
 *   used to build a table with up to 2 non-operational states to transition to.
 *   The default parameter values were selected based on the values used by
 *   Microsoft's and Intel's NVMe drivers. Yet, since we don't implement dynamic
 *   regeneration of the APST table in the event of switching between external
 *   and battery power, the timeouts and tolerances reflect a compromise
 *   between values used by Microsoft for AC and battery scenarios.
 * - If not, we'll configure the table 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.
 */
static int nvme_configure_apst(struct nvme_ctrl *ctrl)
{
        struct nvme_feat_auto_pst *table;
        unsigned apste = 0;
        u64 max_lat_us = 0;
        __le64 target = 0;
        int max_ps = -1;
        int state;
        int ret;
        unsigned last_lt_index = UINT_MAX;

        /*
         * 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. */
                dev_dbg(ctrl->device, "APST disabled\n");
                goto done;
        }

        /*
         * 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. It can be used as the APST idle target
                 * for higher power states.
                 */
                if (apst_primary_timeout_ms && apst_primary_latency_tol_us) {
                        if (!nvme_apst_get_transition_time(total_latency_us,
                                        &transition_ms, &last_lt_index))
                                continue;
                } else {
                        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;
        }

        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);
        apste = 1;

done:
        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;
                if (ctrl->state == NVME_CTRL_LIVE)
                        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,
        },
        {
                /*
                 * This LiteON CL1-3D*-Q11 firmware version has a race
                 * condition associated with actions related to suspend to idle
                 * LiteON has resolved the problem in future firmware
                 */
                .vid = 0x14a4,
                .fr = "22301111",
                .quirks = NVME_QUIRK_SIMPLE_SUSPEND,
        },
        {
                /*
                 * This Kioxia CD6-V Series / HPE PE8030 device times out and
                 * aborts I/O during any load, but more easily reproducible
                 * with discards (fstrim).
                 *
                 * The device is left in a state where it is also not possible
                 * to use "nvme set-feature" to disable APST, but booting with
                 * nvme_core.default_ps_max_latency=0 works.
                 */
                .vid = 0x1e0f,
                .mn = "KCD6XVUL6T40",
                .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;

        if(!(ctrl->quirks & NVME_QUIRK_IGNORE_DEV_SUBNQN)) {
                nqnlen = strnlen(id->subnqn, NVMF_NQN_SIZE);
                if (nqnlen > 0 && nqnlen < NVMF_NQN_SIZE) {
                        strlcpy(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:%04x%04x",
                        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 device *dev)
{
        struct nvme_subsystem *subsys =
                container_of(dev, struct nvme_subsystem, dev);

        if (subsys->instance >= 0)
                ida_free(&nvme_instance_ida, subsys->instance);
        kfree(subsys);
}

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);

        /*
         * Fail matches for discovery subsystems. This results
         * in each discovery controller bound to a unique subsystem.
         * This avoids issues with validating controller values
         * that can only be true when there is a single unique subsystem.
         * There may be multiple and completely independent entities
         * that provide discovery controllers.
         */
        if (!strcmp(subsysnqn, NVME_DISC_SUBSYS_NAME))
                return NULL;

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

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

        switch (subsys->subtype) {
        case NVME_NQN_DISC:
                return sysfs_emit(buf, "discovery\n");
        case NVME_NQN_NVME:
                return sysfs_emit(buf, "nvm\n");
        default:
                return sysfs_emit(buf, "reserved\n");
        }
}
static SUBSYS_ATTR_RO(subsystype, S_IRUGO, nvme_subsys_show_type);

#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 sysfs_emit(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,
        &subsys_attr_subsystype.attr,
#ifdef CONFIG_NVME_MULTIPATH
        &subsys_attr_iopolicy.attr,
#endif
        NULL,
};

static const 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 inline bool nvme_discovery_ctrl(struct nvme_ctrl *ctrl)
{
        return ctrl->opts && ctrl->opts->discovery_nqn;
}

static bool nvme_validate_cntlid(struct nvme_subsystem *subsys,
                struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
{
        struct nvme_ctrl *tmp;

        lockdep_assert_held(&nvme_subsystems_lock);

        list_for_each_entry(tmp, &subsys->ctrls, subsys_entry) {
                if (nvme_state_terminal(tmp))
                        continue;

                if (tmp->cntlid == ctrl->cntlid) {
                        dev_err(ctrl->device,
                                "Duplicate cntlid %u with %s, subsys %s, rejecting\n",
                                ctrl->cntlid, dev_name(tmp->device),
                                subsys->subnqn);
                        return false;
                }

                if ((id->cmic & NVME_CTRL_CMIC_MULTI_CTRL) ||
                    nvme_discovery_ctrl(ctrl))
                        continue;

                dev_err(ctrl->device,
                        "Subsystem does not support multiple controllers\n");
                return false;
        }

        return true;
}

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;

        subsys->instance = -1;
        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;

        /* Versions prior to 1.4 don't necessarily report a valid type */
        if (id->cntrltype == NVME_CTRL_DISC ||
            !strcmp(subsys->subnqn, NVME_DISC_SUBSYS_NAME))
                subsys->subtype = NVME_NQN_DISC;
        else
                subsys->subtype = NVME_NQN_NVME;

        if (nvme_discovery_ctrl(ctrl) && subsys->subtype != NVME_NQN_DISC) {
                dev_err(ctrl->device,
                        "Subsystem %s is not a discovery controller",
                        subsys->subnqn);
                kfree(subsys);
                return -EINVAL;
        }
        subsys->awupf = le16_to_cpu(id->awupf);
        nvme_mpath_default_iopolicy(subsys);

        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", ctrl->instance);
        device_initialize(&subsys->dev);

        mutex_lock(&nvme_subsystems_lock);
        found = __nvme_find_get_subsystem(subsys->subnqn);
        if (found) {
                put_device(&subsys->dev);
                subsys = found;

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

        ret = sysfs_create_link(&subsys->dev.kobj, &ctrl->device->kobj,
                                dev_name(ctrl->device));
        if (ret) {
                dev_err(ctrl->device,
                        "failed to create sysfs link from subsystem.\n");
                goto out_put_subsystem;
        }

        if (!found)
                subsys->instance = ctrl->instance;
        ctrl->subsys = subsys;
        list_add_tail(&ctrl->subsys_entry, &subsys->ctrls);
        mutex_unlock(&nvme_subsystems_lock);
        return 0;

out_put_subsystem:
        nvme_put_subsystem(subsys);
out_unlock:
        mutex_unlock(&nvme_subsystems_lock);
        return ret;
}

int nvme_get_log(struct nvme_ctrl *ctrl, u32 nsid, u8 log_page, u8 lsp, u8 csi,
                void *log, size_t size, u64 offset)
{
        struct nvme_command c = { };
        u32 dwlen = nvme_bytes_to_numd(size);

        c.get_log_page.opcode = nvme_admin_get_log_page;
        c.get_log_page.nsid = cpu_to_le32(nsid);
        c.get_log_page.lid = log_page;
        c.get_log_page.lsp = lsp;
        c.get_log_page.numdl = cpu_to_le16(dwlen & ((1 << 16) - 1));
        c.get_log_page.numdu = cpu_to_le16(dwlen >> 16);
        c.get_log_page.lpol = cpu_to_le32(lower_32_bits(offset));
        c.get_log_page.lpou = cpu_to_le32(upper_32_bits(offset));
        c.get_log_page.csi = csi;

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

static int nvme_get_effects_log(struct nvme_ctrl *ctrl, u8 csi,
                                struct nvme_effects_log **log)
{
        struct nvme_effects_log *cel = xa_load(&ctrl->cels, csi);
        int ret;

        if (cel)
                goto out;

        cel = kzalloc(sizeof(*cel), GFP_KERNEL);
        if (!cel)
                return -ENOMEM;

        ret = nvme_get_log(ctrl, 0x00, NVME_LOG_CMD_EFFECTS, 0, csi,
                        cel, sizeof(*cel), 0);
        if (ret) {
                kfree(cel);
                return ret;
        }

        xa_store(&ctrl->cels, csi, cel, GFP_KERNEL);
out:
        *log = cel;
        return 0;
}

static inline u32 nvme_mps_to_sectors(struct nvme_ctrl *ctrl, u32 units)
{
        u32 page_shift = NVME_CAP_MPSMIN(ctrl->cap) + 12, val;

        if (check_shl_overflow(1U, units + page_shift - 9, &val))
                return UINT_MAX;
        return val;
}

static int nvme_init_non_mdts_limits(struct nvme_ctrl *ctrl)
{
        struct nvme_command c = { };
        struct nvme_id_ctrl_nvm *id;
        int ret;

        if (ctrl->oncs & NVME_CTRL_ONCS_DSM) {
                ctrl->max_discard_sectors = UINT_MAX;
                ctrl->max_discard_segments = NVME_DSM_MAX_RANGES;
        } else {
                ctrl->max_discard_sectors = 0;
                ctrl->max_discard_segments = 0;
        }

        /*
         * Even though NVMe spec explicitly states that MDTS is not applicable
         * to the write-zeroes, we are cautious and limit the size to the
         * controllers max_hw_sectors value, which is based on the MDTS field
         * and possibly other limiting factors.
         */
        if ((ctrl->oncs & NVME_CTRL_ONCS_WRITE_ZEROES) &&
            !(ctrl->quirks & NVME_QUIRK_DISABLE_WRITE_ZEROES))
                ctrl->max_zeroes_sectors = ctrl->max_hw_sectors;
        else
                ctrl->max_zeroes_sectors = 0;

        if (nvme_ctrl_limited_cns(ctrl))
                return 0;

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

        c.identify.opcode = nvme_admin_identify;
        c.identify.cns = NVME_ID_CNS_CS_CTRL;
        c.identify.csi = NVME_CSI_NVM;

        ret = nvme_submit_sync_cmd(ctrl->admin_q, &c, id, sizeof(*id));
        if (ret)
                goto free_data;

        if (id->dmrl)
                ctrl->max_discard_segments = id->dmrl;
        if (id->dmrsl)
                ctrl->max_discard_sectors = le32_to_cpu(id->dmrsl);
        if (id->wzsl)
                ctrl->max_zeroes_sectors = nvme_mps_to_sectors(ctrl, id->wzsl);

free_data:
        kfree(id);
        return ret;
}

static int nvme_init_identify(struct nvme_ctrl *ctrl)
{
        struct nvme_id_ctrl *id;
        u32 max_hw_sectors;
        bool prev_apst_enabled;
        int ret;

        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, NVME_CSI_NVM, &ctrl->effects);
                if (ret < 0)
                        goto out_free;
        }

        if (!(ctrl->ops->flags & NVME_F_FABRICS))
                ctrl->cntlid = le16_to_cpu(id->cntlid);

        if (!ctrl->identified) {
                unsigned 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->crdt[0] = le16_to_cpu(id->crdt1);
        ctrl->crdt[1] = le16_to_cpu(id->crdt2);
        ctrl->crdt[2] = le16_to_cpu(id->crdt3);

        ctrl->oacs = le16_to_cpu(id->oacs);
        ctrl->oncs = le16_to_cpu(id->oncs);
        ctrl->mtfa = le16_to_cpu(id->mtfa);
        ctrl->oaes = le32_to_cpu(id->oaes);
        ctrl->wctemp = le16_to_cpu(id->wctemp);
        ctrl->cctemp = le16_to_cpu(id->cctemp);

        atomic_set(&ctrl->abort_limit, id->acl + 1);
        ctrl->vwc = id->vwc;
        if (id->mdts)
                max_hw_sectors = nvme_mps_to_sectors(ctrl, id->mdts);
        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);
        ctrl->max_namespaces = le32_to_cpu(id->mnan);
        ctrl->ctratt = le32_to_cpu(id->ctratt);

        ctrl->cntrltype = id->cntrltype;
        ctrl->dctype = id->dctype;

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

                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)) {
                        dev_err(ctrl->device,
                                "Mismatching cntlid: Connect %u vs Identify "
                                "%u, rejecting\n",
                                ctrl->cntlid, le16_to_cpu(id->cntlid));
                        ret = -EINVAL;
                        goto out_free;
                }

                if (!nvme_discovery_ctrl(ctrl) && !ctrl->kas) {
                        dev_err(ctrl->device,
                                "keep-alive support is mandatory for fabrics\n");
                        ret = -EINVAL;
                        goto out_free;
                }
        } else {
                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);
        }

        ret = nvme_mpath_init_identify(ctrl, id);
        if (ret < 0)
                goto out_free;

        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);

out_free:
        kfree(id);
        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_ctrl_finish(struct nvme_ctrl *ctrl)
{
        int ret;

        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;
        }

        ctrl->sqsize = min_t(u16, NVME_CAP_MQES(ctrl->cap), ctrl->sqsize);

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

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

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

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

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

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

        if (!ctrl->identified && !nvme_discovery_ctrl(ctrl)) {
                ret = nvme_hwmon_init(ctrl);
                if (ret < 0)
                        return ret;
        }

        ctrl->identified = true;

        return 0;
}
EXPORT_SYMBOL_GPL(nvme_init_ctrl_finish);

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:
                break;
        default:
                return -EWOULDBLOCK;
        }

        nvme_get_ctrl(ctrl);
        if (!try_module_get(ctrl->ops->module)) {
                nvme_put_ctrl(ctrl);
                return -EINVAL;
        }

        file->private_data = ctrl;
        return 0;
}

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

        module_put(ctrl->ops->module);
        nvme_put_ctrl(ctrl);
        return 0;
}

static const struct file_operations nvme_dev_fops = {
        .owner          = THIS_MODULE,
        .open           = nvme_dev_open,
        .release        = nvme_dev_release,
        .unlocked_ioctl = nvme_dev_ioctl,
        .compat_ioctl   = compat_ptr_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_bdev_ops)
                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 sysfs_emit(buf, "uuid.%pU\n", &ids->uuid);

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

        if (memchr_inv(ids->eui64, 0, sizeof(ids->eui64)))
                return sysfs_emit(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 sysfs_emit(buf, "nvme.%04x-%*phN-%*phN-%08x\n", subsys->vendor_id,
                serial_len, subsys->serial, model_len, subsys->model,
                head->ns_id);
}
static DEVICE_ATTR_RO(wwid);

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

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 sysfs_emit(buf, "%pU\n", ids->nguid);
        }
        return sysfs_emit(buf, "%pU\n", &ids->uuid);
}
static DEVICE_ATTR_RO(uuid);

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

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

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,
#ifdef CONFIG_NVME_MULTIPATH
        &dev_attr_ana_grpid.attr,
        &dev_attr_ana_state.attr,
#endif
        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;
        }
#ifdef CONFIG_NVME_MULTIPATH
        if (a == &dev_attr_ana_grpid.attr || a == &dev_attr_ana_state.attr) {
                if (dev_to_disk(dev)->fops != &nvme_bdev_ops) /* per-path attr */
                        return 0;
                if (!nvme_ctrl_use_ana(nvme_get_ns_from_dev(dev)->ctrl))
                        return 0;
        }
#endif
        return a->mode;
}

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

const struct attribute_group *nvme_ns_id_attr_groups[] = {
        &nvme_ns_id_attr_group,
        NULL,
};

#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 sysfs_emit(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 sysfs_emit(buf, "%d\n", ctrl->field);                            \
}                                                                               \
static DEVICE_ATTR(field, S_IRUGO, field##_show, NULL);

nvme_show_int_function(cntlid);
nvme_show_int_function(numa_node);
nvme_show_int_function(queue_count);
nvme_show_int_function(sqsize);
nvme_show_int_function(kato);

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 sysfs_emit(buf, "%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_RESETTING]   = "resetting",
                [NVME_CTRL_CONNECTING]  = "connecting",
                [NVME_CTRL_DELETING]    = "deleting",
                [NVME_CTRL_DELETING_NOIO]= "deleting (no IO)",
                [NVME_CTRL_DEAD]        = "dead",
        };

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

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

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

        return sysfs_emit(buf, "%s\n", ctrl->opts->host->nqn);
}
static DEVICE_ATTR(hostnqn, S_IRUGO, nvme_sysfs_show_hostnqn, NULL);

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

        return sysfs_emit(buf, "%pU\n", &ctrl->opts->host->id);
}
static DEVICE_ATTR(hostid, S_IRUGO, nvme_sysfs_show_hostid, 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 ssize_t nvme_ctrl_loss_tmo_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
        struct nvmf_ctrl_options *opts = ctrl->opts;

        if (ctrl->opts->max_reconnects == -1)
                return sysfs_emit(buf, "off\n");
        return sysfs_emit(buf, "%d\n",
                          opts->max_reconnects * opts->reconnect_delay);
}

static ssize_t nvme_ctrl_loss_tmo_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
        struct nvmf_ctrl_options *opts = ctrl->opts;
        int ctrl_loss_tmo, err;

        err = kstrtoint(buf, 10, &ctrl_loss_tmo);
        if (err)
                return -EINVAL;

        if (ctrl_loss_tmo < 0)
                opts->max_reconnects = -1;
        else
                opts->max_reconnects = DIV_ROUND_UP(ctrl_loss_tmo,
                                                opts->reconnect_delay);
        return count;
}
static DEVICE_ATTR(ctrl_loss_tmo, S_IRUGO | S_IWUSR,
        nvme_ctrl_loss_tmo_show, nvme_ctrl_loss_tmo_store);

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

        if (ctrl->opts->reconnect_delay == -1)
                return sysfs_emit(buf, "off\n");
        return sysfs_emit(buf, "%d\n", ctrl->opts->reconnect_delay);
}

static ssize_t nvme_ctrl_reconnect_delay_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
        unsigned int v;
        int err;

        err = kstrtou32(buf, 10, &v);
        if (err)
                return err;

        ctrl->opts->reconnect_delay = v;
        return count;
}
static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR,
        nvme_ctrl_reconnect_delay_show, nvme_ctrl_reconnect_delay_store);

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

        if (ctrl->opts->fast_io_fail_tmo == -1)
                return sysfs_emit(buf, "off\n");
        return sysfs_emit(buf, "%d\n", ctrl->opts->fast_io_fail_tmo);
}

static ssize_t nvme_ctrl_fast_io_fail_tmo_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
        struct nvmf_ctrl_options *opts = ctrl->opts;
        int fast_io_fail_tmo, err;

        err = kstrtoint(buf, 10, &fast_io_fail_tmo);
        if (err)
                return -EINVAL;

        if (fast_io_fail_tmo < 0)
                opts->fast_io_fail_tmo = -1;
        else
                opts->fast_io_fail_tmo = fast_io_fail_tmo;
        return count;
}
static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
        nvme_ctrl_fast_io_fail_tmo_show, nvme_ctrl_fast_io_fail_tmo_store);

static ssize_t cntrltype_show(struct device *dev,
                              struct device_attribute *attr, char *buf)
{
        static const char * const type[] = {
                [NVME_CTRL_IO] = "io\n",
                [NVME_CTRL_DISC] = "discovery\n",
                [NVME_CTRL_ADMIN] = "admin\n",
        };
        struct nvme_ctrl *ctrl = dev_get_drvdata(dev);

        if (ctrl->cntrltype > NVME_CTRL_ADMIN || !type[ctrl->cntrltype])
                return sysfs_emit(buf, "reserved\n");

        return sysfs_emit(buf, type[ctrl->cntrltype]);
}
static DEVICE_ATTR_RO(cntrltype);

static ssize_t dctype_show(struct device *dev,
                           struct device_attribute *attr, char *buf)
{
        static const char * const type[] = {
                [NVME_DCTYPE_NOT_REPORTED] = "none\n",
                [NVME_DCTYPE_DDC] = "ddc\n",
                [NVME_DCTYPE_CDC] = "cdc\n",
        };
        struct nvme_ctrl *ctrl = dev_get_drvdata(dev);

        if (ctrl->dctype > NVME_DCTYPE_CDC || !type[ctrl->dctype])
                return sysfs_emit(buf, "reserved\n");

        return sysfs_emit(buf, type[ctrl->dctype]);
}
static DEVICE_ATTR_RO(dctype);

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,
        &dev_attr_numa_node.attr,
        &dev_attr_queue_count.attr,
        &dev_attr_sqsize.attr,
        &dev_attr_hostnqn.attr,
        &dev_attr_hostid.attr,
        &dev_attr_ctrl_loss_tmo.attr,
        &dev_attr_reconnect_delay.attr,
        &dev_attr_fast_io_fail_tmo.attr,
        &dev_attr_kato.attr,
        &dev_attr_cntrltype.attr,
        &dev_attr_dctype.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;
        if (a == &dev_attr_hostnqn.attr && !ctrl->opts)
                return 0;
        if (a == &dev_attr_hostid.attr && !ctrl->opts)
                return 0;
        if (a == &dev_attr_ctrl_loss_tmo.attr && !ctrl->opts)
                return 0;
        if (a == &dev_attr_reconnect_delay.attr && !ctrl->opts)
                return 0;
        if (a == &dev_attr_fast_io_fail_tmo.attr && !ctrl->opts)
                return 0;

        return a->mode;
}

static const 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)
                        continue;
                if (!list_empty(&h->list) && nvme_tryget_ns_head(h))
                        return h;
        }

        return NULL;
}

static int nvme_subsys_check_duplicate_ids(struct nvme_subsystem *subsys,
                struct nvme_ns_ids *ids)
{
        bool has_uuid = !uuid_is_null(&ids->uuid);
        bool has_nguid = memchr_inv(ids->nguid, 0, sizeof(ids->nguid));
        bool has_eui64 = memchr_inv(ids->eui64, 0, sizeof(ids->eui64));
        struct nvme_ns_head *h;

        lockdep_assert_held(&subsys->lock);

        list_for_each_entry(h, &subsys->nsheads, entry) {
                if (has_uuid && uuid_equal(&ids->uuid, &h->ids.uuid))
                        return -EINVAL;
                if (has_nguid &&
                    memcmp(&ids->nguid, &h->ids.nguid, sizeof(ids->nguid)) == 0)
                        return -EINVAL;
                if (has_eui64 &&
                    memcmp(&ids->eui64, &h->ids.eui64, sizeof(ids->eui64)) == 0)
                        return -EINVAL;
        }

        return 0;
}

static void nvme_cdev_rel(struct device *dev)
{
        ida_free(&nvme_ns_chr_minor_ida, MINOR(dev->devt));
}

void nvme_cdev_del(struct cdev *cdev, struct device *cdev_device)
{
        cdev_device_del(cdev, cdev_device);
        put_device(cdev_device);
}

int nvme_cdev_add(struct cdev *cdev, struct device *cdev_device,
                const struct file_operations *fops, struct module *owner)
{
        int minor, ret;

        minor = ida_alloc(&nvme_ns_chr_minor_ida, GFP_KERNEL);
        if (minor < 0)
                return minor;
        cdev_device->devt = MKDEV(MAJOR(nvme_ns_chr_devt), minor);
        cdev_device->class = nvme_ns_chr_class;
        cdev_device->release = nvme_cdev_rel;
        device_initialize(cdev_device);
        cdev_init(cdev, fops);
        cdev->owner = owner;
        ret = cdev_device_add(cdev, cdev_device);
        if (ret)
                put_device(cdev_device);

        return ret;
}

static int nvme_ns_chr_open(struct inode *inode, struct file *file)
{
        return nvme_ns_open(container_of(inode->i_cdev, struct nvme_ns, cdev));
}

static int nvme_ns_chr_release(struct inode *inode, struct file *file)
{
        nvme_ns_release(container_of(inode->i_cdev, struct nvme_ns, cdev));
        return 0;
}

static const struct file_operations nvme_ns_chr_fops = {
        .owner          = THIS_MODULE,
        .open           = nvme_ns_chr_open,
        .release        = nvme_ns_chr_release,
        .unlocked_ioctl = nvme_ns_chr_ioctl,
        .compat_ioctl   = compat_ptr_ioctl,
};

static int nvme_add_ns_cdev(struct nvme_ns *ns)
{
        int ret;

        ns->cdev_device.parent = ns->ctrl->device;
        ret = dev_set_name(&ns->cdev_device, "ng%dn%d",
                           ns->ctrl->instance, ns->head->instance);
        if (ret)
                return ret;

        return nvme_cdev_add(&ns->cdev, &ns->cdev_device, &nvme_ns_chr_fops,
                             ns->ctrl->ops->module);
}

static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
                unsigned nsid, struct nvme_ns_ids *ids)
{
        struct nvme_ns_head *head;
        size_t size = sizeof(*head);
        int ret = -ENOMEM;

#ifdef CONFIG_NVME_MULTIPATH
        size += num_possible_nodes() * sizeof(struct nvme_ns *);
#endif

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

        if (head->ids.csi) {
                ret = nvme_get_effects_log(ctrl, head->ids.csi, &head->effects);
                if (ret)
                        goto out_cleanup_srcu;
        } else
                head->effects = ctrl->effects;

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

        list_add_tail(&head->entry, &ctrl->subsys->nsheads);

        kref_get(&ctrl->subsys->ref);

        return head;
out_cleanup_srcu:
        cleanup_srcu_struct(&head->srcu);
out_ida_remove:
        ida_free(&ctrl->subsys->ns_ida, head->instance);
out_free_head:
        kfree(head);
out:
        if (ret > 0)
                ret = blk_status_to_errno(nvme_error_status(ret));
        return ERR_PTR(ret);
}

static int nvme_global_check_duplicate_ids(struct nvme_subsystem *this,
                struct nvme_ns_ids *ids)
{
        struct nvme_subsystem *s;
        int ret = 0;

        /*
         * Note that this check is racy as we try to avoid holding the global
         * lock over the whole ns_head creation.  But it is only intended as
         * a sanity check anyway.
         */
        mutex_lock(&nvme_subsystems_lock);
        list_for_each_entry(s, &nvme_subsystems, entry) {
                if (s == this)
                        continue;
                mutex_lock(&s->lock);
                ret = nvme_subsys_check_duplicate_ids(s, ids);
                mutex_unlock(&s->lock);
                if (ret)
                        break;
        }
        mutex_unlock(&nvme_subsystems_lock);

        return ret;
}

static int nvme_init_ns_head(struct nvme_ns *ns, unsigned nsid,
                struct nvme_ns_ids *ids, bool is_shared)
{
        struct nvme_ctrl *ctrl = ns->ctrl;
        struct nvme_ns_head *head = NULL;
        int ret;

        ret = nvme_global_check_duplicate_ids(ctrl->subsys, ids);
        if (ret) {
                dev_err(ctrl->device,
                        "globally duplicate IDs for nsid %d\n", nsid);
                return ret;
        }

        mutex_lock(&ctrl->subsys->lock);
        head = nvme_find_ns_head(ctrl->subsys, nsid);
        if (!head) {
                ret = nvme_subsys_check_duplicate_ids(ctrl->subsys, ids);
                if (ret) {
                        dev_err(ctrl->device,
                                "duplicate IDs in subsystem for nsid %d\n",
                                nsid);
                        goto out_unlock;
                }
                head = nvme_alloc_ns_head(ctrl, nsid, ids);
                if (IS_ERR(head)) {
                        ret = PTR_ERR(head);
                        goto out_unlock;
                }
                head->shared = is_shared;
        } else {
                ret = -EINVAL;
                if (!is_shared || !head->shared) {
                        dev_err(ctrl->device,
                                "Duplicate unshared namespace %d\n", nsid);
                        goto out_put_ns_head;
                }
                if (!nvme_ns_ids_equal(&head->ids, ids)) {
                        dev_err(ctrl->device,
                                "IDs don't match for shared namespace %d\n",
                                        nsid);
                        goto out_put_ns_head;
                }

                if (!multipath && !list_empty(&head->list)) {
                        dev_warn(ctrl->device,
                                "Found shared namespace %d, but multipathing not supported.\n",
                                nsid);
                        dev_warn_once(ctrl->device,
                                "Support for shared namespaces without CONFIG_NVME_MULTIPATH is deprecated and will be removed in Linux 6.0\n.");
                }
        }

        list_add_tail_rcu(&ns->siblings, &head->list);
        ns->head = head;
        mutex_unlock(&ctrl->subsys->lock);
        return 0;

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

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

        down_read(&ctrl->namespaces_rwsem);
        list_for_each_entry(ns, &ctrl->namespaces, list) {
                if (ns->head->ns_id == nsid) {
                        if (!nvme_get_ns(ns))
                                continue;
                        ret = ns;
                        break;
                }
                if (ns->head->ns_id > nsid)
                        break;
        }
        up_read(&ctrl->namespaces_rwsem);
        return ret;
}
EXPORT_SYMBOL_NS_GPL(nvme_find_get_ns, NVME_TARGET_PASSTHRU);

/*
 * Add the namespace to the controller list while keeping the list ordered.
 */
static void nvme_ns_add_to_ctrl_list(struct nvme_ns *ns)
{
        struct nvme_ns *tmp;

        list_for_each_entry_reverse(tmp, &ns->ctrl->namespaces, list) {
                if (tmp->head->ns_id < ns->head->ns_id) {
                        list_add(&ns->list, &tmp->list);
                        return;
                }
        }
        list_add(&ns->list, &ns->ctrl->namespaces);
}

static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
                struct nvme_ns_ids *ids)
{
        struct nvme_ns *ns;
        struct gendisk *disk;
        struct nvme_id_ns *id;
        int node = ctrl->numa_node;

        if (nvme_identify_ns(ctrl, nsid, ids, &id))
                return;

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

        disk = blk_mq_alloc_disk(ctrl->tagset, ns);
        if (IS_ERR(disk))
                goto out_free_ns;
        disk->fops = &nvme_bdev_ops;
        disk->private_data = ns;

        ns->disk = disk;
        ns->queue = disk->queue;

        if (ctrl->opts && ctrl->opts->data_digest)
                blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, ns->queue);

        blk_queue_flag_set(QUEUE_FLAG_NONROT, ns->queue);
        if (ctrl->ops->flags & NVME_F_PCI_P2PDMA)
                blk_queue_flag_set(QUEUE_FLAG_PCI_P2PDMA, ns->queue);

        ns->ctrl = ctrl;
        kref_init(&ns->kref);

        if (nvme_init_ns_head(ns, nsid, ids, id->nmic & NVME_NS_NMIC_SHARED))
                goto out_cleanup_disk;

        /*
         * If multipathing is enabled, the device name for all disks and not
         * just those that represent shared namespaces needs to be based on the
         * subsystem instance.  Using the controller instance for private
         * namespaces could lead to naming collisions between shared and private
         * namespaces if they don't use a common numbering scheme.
         *
         * If multipathing is not enabled, disk names must use the controller
         * instance as shared namespaces will show up as multiple block
         * devices.
         */
        if (ns->head->disk) {
                sprintf(disk->disk_name, "nvme%dc%dn%d", ctrl->subsys->instance,
                        ctrl->instance, ns->head->instance);
                disk->flags |= GENHD_FL_HIDDEN;
        } else if (multipath) {
                sprintf(disk->disk_name, "nvme%dn%d", ctrl->subsys->instance,
                        ns->head->instance);
        } else {
                sprintf(disk->disk_name, "nvme%dn%d", ctrl->instance,
                        ns->head->instance);
        }

        if (nvme_update_ns_info(ns, id))
                goto out_unlink_ns;

        down_write(&ctrl->namespaces_rwsem);
        nvme_ns_add_to_ctrl_list(ns);
        up_write(&ctrl->namespaces_rwsem);
        nvme_get_ctrl(ctrl);

        if (device_add_disk(ctrl->device, ns->disk, nvme_ns_id_attr_groups))
                goto out_cleanup_ns_from_list;

        if (!nvme_ns_head_multipath(ns->head))
                nvme_add_ns_cdev(ns);

        nvme_mpath_add_disk(ns, id);
        nvme_fault_inject_init(&ns->fault_inject, ns->disk->disk_name);
        kfree(id);

        return;

 out_cleanup_ns_from_list:
        nvme_put_ctrl(ctrl);
        down_write(&ctrl->namespaces_rwsem);
        list_del_init(&ns->list);
        up_write(&ctrl->namespaces_rwsem);
 out_unlink_ns:
        mutex_lock(&ctrl->subsys->lock);
        list_del_rcu(&ns->siblings);
        if (list_empty(&ns->head->list))
                list_del_init(&ns->head->entry);
        mutex_unlock(&ctrl->subsys->lock);
        nvme_put_ns_head(ns->head);
 out_cleanup_disk:
        blk_cleanup_disk(disk);
 out_free_ns:
        kfree(ns);
 out_free_id:
        kfree(id);
}

static void nvme_ns_remove(struct nvme_ns *ns)
{
        bool last_path = false;

        if (test_and_set_bit(NVME_NS_REMOVING, &ns->flags))
                return;

        clear_bit(NVME_NS_READY, &ns->flags);
        set_capacity(ns->disk, 0);
        nvme_fault_inject_fini(&ns->fault_inject);

        mutex_lock(&ns->ctrl->subsys->lock);
        list_del_rcu(&ns->siblings);
        if (list_empty(&ns->head->list)) {
                list_del_init(&ns->head->entry);
                last_path = true;
        }
        mutex_unlock(&ns->ctrl->subsys->lock);

        /* guarantee not available in head->list */
        synchronize_rcu();

        /* wait for concurrent submissions */
        if (nvme_mpath_clear_current_path(ns))
                synchronize_srcu(&ns->head->srcu);

        if (!nvme_ns_head_multipath(ns->head))
                nvme_cdev_del(&ns->cdev, &ns->cdev_device);
        del_gendisk(ns->disk);
        blk_cleanup_queue(ns->queue);

        down_write(&ns->ctrl->namespaces_rwsem);
        list_del_init(&ns->list);
        up_write(&ns->ctrl->namespaces_rwsem);

        if (last_path)
                nvme_mpath_shutdown_disk(ns->head);
        nvme_put_ns(ns);
}

static void nvme_ns_remove_by_nsid(struct nvme_ctrl *ctrl, u32 nsid)
{
        struct nvme_ns *ns = nvme_find_get_ns(ctrl, nsid);

        if (ns) {
                nvme_ns_remove(ns);
                nvme_put_ns(ns);
        }
}

static void nvme_validate_ns(struct nvme_ns *ns, struct nvme_ns_ids *ids)
{
        struct nvme_id_ns *id;
        int ret = NVME_SC_INVALID_NS | NVME_SC_DNR;

        if (test_bit(NVME_NS_DEAD, &ns->flags))
                goto out;

        ret = nvme_identify_ns(ns->ctrl, ns->head->ns_id, ids, &id);
        if (ret)
                goto out;

        ret = NVME_SC_INVALID_NS | NVME_SC_DNR;
        if (!nvme_ns_ids_equal(&ns->head->ids, ids)) {
                dev_err(ns->ctrl->device,
                        "identifiers changed for nsid %d\n", ns->head->ns_id);
                goto out_free_id;
        }

        ret = nvme_update_ns_info(ns, id);

out_free_id:
        kfree(id);
out:
        /*
         * Only remove the namespace if we got a fatal error back from the
         * device, otherwise ignore the error and just move on.
         *
         * TODO: we should probably schedule a delayed retry here.
         */
        if (ret > 0 && (ret & NVME_SC_DNR))
                nvme_ns_remove(ns);
}

static void nvme_validate_or_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
{
        struct nvme_ns_ids ids = { };
        struct nvme_ns *ns;

        if (nvme_identify_ns_descs(ctrl, nsid, &ids))
                return;

        ns = nvme_find_get_ns(ctrl, nsid);
        if (ns) {
                nvme_validate_ns(ns, &ids);
                nvme_put_ns(ns);
                return;
        }

        switch (ids.csi) {
        case NVME_CSI_NVM:
                nvme_alloc_ns(ctrl, nsid, &ids);
                break;
        case NVME_CSI_ZNS:
                if (!IS_ENABLED(CONFIG_BLK_DEV_ZONED)) {
                        dev_warn(ctrl->device,
                                "nsid %u not supported without CONFIG_BLK_DEV_ZONED\n",
                                nsid);
                        break;
                }
                if (!nvme_multi_css(ctrl)) {
                        dev_warn(ctrl->device,
                                "command set not reported for nsid: %d\n",
                                nsid);
                        break;
                }
                nvme_alloc_ns(ctrl, nsid, &ids);
                break;
        default:
                dev_warn(ctrl->device, "unknown csi %u for nsid %u\n",
                        ids.csi, nsid);
                break;
        }
}

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

        down_write(&ctrl->namespaces_rwsem);
        list_for_each_entry_safe(ns, next, &ctrl->namespaces, list) {
                if (ns->head->ns_id > nsid || test_bit(NVME_NS_DEAD, &ns->flags))
                        list_move_tail(&ns->list, &rm_list);
        }
        up_write(&ctrl->namespaces_rwsem);

        list_for_each_entry_safe(ns, next, &rm_list, list)
                nvme_ns_remove(ns);

}

static int nvme_scan_ns_list(struct nvme_ctrl *ctrl)
{
        const int nr_entries = NVME_IDENTIFY_DATA_SIZE / sizeof(__le32);
        __le32 *ns_list;
        u32 prev = 0;
        int ret = 0, i;

        if (nvme_ctrl_limited_cns(ctrl))
                return -EOPNOTSUPP;

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

        for (;;) {
                struct nvme_command cmd = {
                        .identify.opcode        = nvme_admin_identify,
                        .identify.cns           = NVME_ID_CNS_NS_ACTIVE_LIST,
                        .identify.nsid          = cpu_to_le32(prev),
                };

                ret = nvme_submit_sync_cmd(ctrl->admin_q, &cmd, ns_list,
                                            NVME_IDENTIFY_DATA_SIZE);
                if (ret) {
                        dev_warn(ctrl->device,
                                "Identify NS List failed (status=0x%x)\n", ret);
                        goto free;
                }

                for (i = 0; i < nr_entries; i++) {
                        u32 nsid = le32_to_cpu(ns_list[i]);

                        if (!nsid)      /* end of the list? */
                                goto out;
                        nvme_validate_or_alloc_ns(ctrl, nsid);
                        while (++prev < nsid)
                                nvme_ns_remove_by_nsid(ctrl, prev);
                }
        }
 out:
        nvme_remove_invalid_namespaces(ctrl, prev);
 free:
        kfree(ns_list);
        return ret;
}

static void nvme_scan_ns_sequential(struct nvme_ctrl *ctrl)
{
        struct nvme_id_ctrl *id;
        u32 nn, i;

        if (nvme_identify_ctrl(ctrl, &id))
                return;
        nn = le32_to_cpu(id->nn);
        kfree(id);

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

        nvme_remove_invalid_namespaces(ctrl, nn);
}

static void nvme_clear_changed_ns_log(struct nvme_ctrl *ctrl)
{
        size_t log_size = NVME_MAX_CHANGED_NAMESPACES * sizeof(__le32);
        __le32 *log;
        int error;

        log = kzalloc(log_size, GFP_KERNEL);
        if (!log)
                return;

        /*
         * We need to read the log to clear the AEN, but we don't want to rely
         * on it for the changed namespace information as userspace could have
         * raced with us in reading the log page, which could cause us to miss
         * updates.
         */
        error = nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_CHANGED_NS, 0,
                        NVME_CSI_NVM, log, log_size, 0);
        if (error)
                dev_warn(ctrl->device,
                        "reading changed ns log failed: %d\n", error);

        kfree(log);
}

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

        /* No tagset on a live ctrl means IO queues could not created */
        if (ctrl->state != NVME_CTRL_LIVE || !ctrl->tagset)
                return;

        if (test_and_clear_bit(NVME_AER_NOTICE_NS_CHANGED, &ctrl->events)) {
                dev_info(ctrl->device, "rescanning namespaces.\n");
                nvme_clear_changed_ns_log(ctrl);
        }

        mutex_lock(&ctrl->scan_lock);
        if (nvme_scan_ns_list(ctrl) != 0)
                nvme_scan_ns_sequential(ctrl);
        mutex_unlock(&ctrl->scan_lock);
}

/*
 * 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;
        LIST_HEAD(ns_list);

        /*
         * make sure to requeue I/O to all namespaces as these
         * might result from the scan itself and must complete
         * for the scan_work to make progress
         */
        nvme_mpath_clear_ctrl_paths(ctrl);

        /* prevent racing with ns scanning */
        flush_work(&ctrl->scan_work);

        /*
         * 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);

        /* this is a no-op when called from the controller reset handler */
        nvme_change_ctrl_state(ctrl, NVME_CTRL_DELETING_NOIO);

        down_write(&ctrl->namespaces_rwsem);
        list_splice_init(&ctrl->namespaces, &ns_list);
        up_write(&ctrl->namespaces_rwsem);

        list_for_each_entry_safe(ns, next, &ns_list, list)
                nvme_ns_remove(ns);
}
EXPORT_SYMBOL_GPL(nvme_remove_namespaces);

static int nvme_class_uevent(struct device *dev, struct kobj_uevent_env *env)
{
        struct nvme_ctrl *ctrl =
                container_of(dev, struct nvme_ctrl, ctrl_device);
        struct nvmf_ctrl_options *opts = ctrl->opts;
        int ret;

        ret = add_uevent_var(env, "NVME_TRTYPE=%s", ctrl->ops->name);
        if (ret)
                return ret;

        if (opts) {
                ret = add_uevent_var(env, "NVME_TRADDR=%s", opts->traddr);
                if (ret)
                        return ret;

                ret = add_uevent_var(env, "NVME_TRSVCID=%s",
                                opts->trsvcid ?: "none");
                if (ret)
                        return ret;

                ret = add_uevent_var(env, "NVME_HOST_TRADDR=%s",
                                opts->host_traddr ?: "none");
                if (ret)
                        return ret;

                ret = add_uevent_var(env, "NVME_HOST_IFACE=%s",
                                opts->host_iface ?: "none");
        }
        return ret;
}

static void nvme_change_uevent(struct nvme_ctrl *ctrl, char *envdata)
{
        char *envp[2] = { envdata, NULL };

        kobject_uevent_env(&ctrl->device->kobj, KOBJ_CHANGE, envp);
}

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);

        /*
         * The transport drivers must guarantee AER submission here is safe by
         * flushing ctrl async_event_work after changing the controller state
         * from LIVE and before freeing the admin queue.
        */
        if (ctrl->state == NVME_CTRL_LIVE)
                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_NSID_ALL, NVME_LOG_FW_SLOT, 0, NVME_CSI_NVM,
                        log, sizeof(*log), 0))
                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_try_sched_reset(ctrl);
                        return;
                }
                msleep(100);
        }

        if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_LIVE))
                return;

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

static void nvme_handle_aen_notice(struct nvme_ctrl *ctrl, u32 result)
{
        u32 aer_notice_type = (result & 0xff00) >> 8;

        trace_nvme_async_event(ctrl, aer_notice_type);

        switch (aer_notice_type) {
        case NVME_AER_NOTICE_NS_CHANGED:
                set_bit(NVME_AER_NOTICE_NS_CHANGED, &ctrl->events);
                nvme_queue_scan(ctrl);
                break;
        case NVME_AER_NOTICE_FW_ACT_STARTING:
                /*
                 * We are (ab)using the RESETTING state to prevent subsequent
                 * recovery actions from interfering with the controller's
                 * firmware activation.
                 */
                if (nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING))
                        queue_work(nvme_wq, &ctrl->fw_act_work);
                break;
#ifdef CONFIG_NVME_MULTIPATH
        case NVME_AER_NOTICE_ANA:
                if (!ctrl->ana_log_buf)
                        break;
                queue_work(nvme_wq, &ctrl->ana_work);
                break;
#endif
        case NVME_AER_NOTICE_DISC_CHANGED:
                ctrl->aen_result = result;
                break;
        default:
                dev_warn(ctrl->device, "async event result %08x\n", result);
        }
}

void nvme_complete_async_event(struct nvme_ctrl *ctrl, __le16 status,
                volatile union nvme_result *res)
{
        u32 result = le32_to_cpu(res->u32);
        u32 aer_type = result & 0x07;

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

        switch (aer_type) {
        case NVME_AER_NOTICE:
                nvme_handle_aen_notice(ctrl, result);
                break;
        case NVME_AER_ERROR:
        case NVME_AER_SMART:
        case NVME_AER_CSS:
        case NVME_AER_VS:
                trace_nvme_async_event(ctrl, aer_type);
                ctrl->aen_result = result;
                break;
        default:
                break;
        }
        queue_work(nvme_wq, &ctrl->async_event_work);
}
EXPORT_SYMBOL_GPL(nvme_complete_async_event);

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

void nvme_start_ctrl(struct nvme_ctrl *ctrl)
{
        nvme_start_keep_alive(ctrl);

        nvme_enable_aen(ctrl);

        if (ctrl->queue_count > 1) {
                nvme_queue_scan(ctrl);
                nvme_start_queues(ctrl);
        }

        nvme_change_uevent(ctrl, "NVME_EVENT=connected");
}
EXPORT_SYMBOL_GPL(nvme_start_ctrl);

void nvme_uninit_ctrl(struct nvme_ctrl *ctrl)
{
        nvme_hwmon_exit(ctrl);
        nvme_fault_inject_fini(&ctrl->fault_inject);
        dev_pm_qos_hide_latency_tolerance(ctrl->device);
        cdev_device_del(&ctrl->cdev, ctrl->device);
        nvme_put_ctrl(ctrl);
}
EXPORT_SYMBOL_GPL(nvme_uninit_ctrl);

static void nvme_free_cels(struct nvme_ctrl *ctrl)
{
        struct nvme_effects_log *cel;
        unsigned long i;

        xa_for_each(&ctrl->cels, i, cel) {
                xa_erase(&ctrl->cels, i);
                kfree(cel);
        }

        xa_destroy(&ctrl->cels);
}

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;

        if (!subsys || ctrl->instance != subsys->instance)
                ida_free(&nvme_instance_ida, ctrl->instance);

        nvme_free_cels(ctrl);
        nvme_mpath_uninit(ctrl);
        __free_page(ctrl->discard_page);

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

        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;
        clear_bit(NVME_CTRL_FAILFAST_EXPIRED, &ctrl->flags);
        spin_lock_init(&ctrl->lock);
        mutex_init(&ctrl->scan_lock);
        INIT_LIST_HEAD(&ctrl->namespaces);
        xa_init(&ctrl->cels);
        init_rwsem(&ctrl->namespaces_rwsem);
        ctrl->dev = dev;
        ctrl->ops = ops;
        ctrl->quirks = quirks;
        ctrl->numa_node = NUMA_NO_NODE;
        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);
        init_waitqueue_head(&ctrl->state_wq);

        INIT_DELAYED_WORK(&ctrl->ka_work, nvme_keep_alive_work);
        INIT_DELAYED_WORK(&ctrl->failfast_work, nvme_failfast_work);
        memset(&ctrl->ka_cmd, 0, sizeof(ctrl->ka_cmd));
        ctrl->ka_cmd.common.opcode = nvme_admin_keep_alive;

        BUILD_BUG_ON(NVME_DSM_MAX_RANGES * sizeof(struct nvme_dsm_range) >
                        PAGE_SIZE);
        ctrl->discard_page = alloc_page(GFP_KERNEL);
        if (!ctrl->discard_page) {
                ret = -ENOMEM;
                goto out;
        }

        ret = ida_alloc(&nvme_instance_ida, 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_ctrl_base_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;

        nvme_get_ctrl(ctrl);
        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));

        nvme_fault_inject_init(&ctrl->fault_inject, dev_name(ctrl->device));
        nvme_mpath_init_ctrl(ctrl);

        return 0;
out_free_name:
        nvme_put_ctrl(ctrl);
        kfree_const(ctrl->device->kobj.name);
out_release_instance:
        ida_free(&nvme_instance_ida, ctrl->instance);
out:
        if (ctrl->discard_page)
                __free_page(ctrl->discard_page);
        return ret;
}
EXPORT_SYMBOL_GPL(nvme_init_ctrl);

static void nvme_start_ns_queue(struct nvme_ns *ns)
{
        if (test_and_clear_bit(NVME_NS_STOPPED, &ns->flags))
                blk_mq_unquiesce_queue(ns->queue);
}

static void nvme_stop_ns_queue(struct nvme_ns *ns)
{
        if (!test_and_set_bit(NVME_NS_STOPPED, &ns->flags))
                blk_mq_quiesce_queue(ns->queue);
        else
                blk_mq_wait_quiesce_done(ns->queue);
}

/*
 * Prepare a queue for teardown.
 *
 * This must forcibly unquiesce queues to avoid blocking dispatch, and only set
 * the capacity to 0 after that to avoid blocking dispatchers that may be
 * holding bd_butex.  This will end buffered writers dirtying pages that can't
 * be synced.
 */
static void nvme_set_queue_dying(struct nvme_ns *ns)
{
        if (test_and_set_bit(NVME_NS_DEAD, &ns->flags))
                return;

        blk_mark_disk_dead(ns->disk);
        nvme_start_ns_queue(ns);

        set_capacity_and_notify(ns->disk, 0);
}

/**
 * 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;

        down_read(&ctrl->namespaces_rwsem);

        /* Forcibly unquiesce queues to avoid blocking dispatch */
        if (ctrl->admin_q && !blk_queue_dying(ctrl->admin_q))
                nvme_start_admin_queue(ctrl);

        list_for_each_entry(ns, &ctrl->namespaces, list)
                nvme_set_queue_dying(ns);

        up_read(&ctrl->namespaces_rwsem);
}
EXPORT_SYMBOL_GPL(nvme_kill_queues);

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

        down_read(&ctrl->namespaces_rwsem);
        list_for_each_entry(ns, &ctrl->namespaces, list)
                blk_mq_unfreeze_queue(ns->queue);
        up_read(&ctrl->namespaces_rwsem);
}
EXPORT_SYMBOL_GPL(nvme_unfreeze);

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

        down_read(&ctrl->namespaces_rwsem);
        list_for_each_entry(ns, &ctrl->namespaces, list) {
                timeout = blk_mq_freeze_queue_wait_timeout(ns->queue, timeout);
                if (timeout <= 0)
                        break;
        }
        up_read(&ctrl->namespaces_rwsem);
        return timeout;
}
EXPORT_SYMBOL_GPL(nvme_wait_freeze_timeout);

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

        down_read(&ctrl->namespaces_rwsem);
        list_for_each_entry(ns, &ctrl->namespaces, list)
                blk_mq_freeze_queue_wait(ns->queue);
        up_read(&ctrl->namespaces_rwsem);
}
EXPORT_SYMBOL_GPL(nvme_wait_freeze);

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

        down_read(&ctrl->namespaces_rwsem);
        list_for_each_entry(ns, &ctrl->namespaces, list)
                blk_freeze_queue_start(ns->queue);
        up_read(&ctrl->namespaces_rwsem);
}
EXPORT_SYMBOL_GPL(nvme_start_freeze);

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

        down_read(&ctrl->namespaces_rwsem);
        list_for_each_entry(ns, &ctrl->namespaces, list)
                nvme_stop_ns_queue(ns);
        up_read(&ctrl->namespaces_rwsem);
}
EXPORT_SYMBOL_GPL(nvme_stop_queues);

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

        down_read(&ctrl->namespaces_rwsem);
        list_for_each_entry(ns, &ctrl->namespaces, list)
                nvme_start_ns_queue(ns);
        up_read(&ctrl->namespaces_rwsem);
}
EXPORT_SYMBOL_GPL(nvme_start_queues);

void nvme_stop_admin_queue(struct nvme_ctrl *ctrl)
{
        if (!test_and_set_bit(NVME_CTRL_ADMIN_Q_STOPPED, &ctrl->flags))
                blk_mq_quiesce_queue(ctrl->admin_q);
        else
                blk_mq_wait_quiesce_done(ctrl->admin_q);
}
EXPORT_SYMBOL_GPL(nvme_stop_admin_queue);

void nvme_start_admin_queue(struct nvme_ctrl *ctrl)
{
        if (test_and_clear_bit(NVME_CTRL_ADMIN_Q_STOPPED, &ctrl->flags))
                blk_mq_unquiesce_queue(ctrl->admin_q);
}
EXPORT_SYMBOL_GPL(nvme_start_admin_queue);

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

        down_read(&ctrl->namespaces_rwsem);
        list_for_each_entry(ns, &ctrl->namespaces, list)
                blk_sync_queue(ns->queue);
        up_read(&ctrl->namespaces_rwsem);
}
EXPORT_SYMBOL_GPL(nvme_sync_io_queues);

void nvme_sync_queues(struct nvme_ctrl *ctrl)
{
        nvme_sync_io_queues(ctrl);
        if (ctrl->admin_q)
                blk_sync_queue(ctrl->admin_q);
}
EXPORT_SYMBOL_GPL(nvme_sync_queues);

struct nvme_ctrl *nvme_ctrl_from_file(struct file *file)
{
        if (file->f_op != &nvme_dev_fops)
                return NULL;
        return file->private_data;
}
EXPORT_SYMBOL_NS_GPL(nvme_ctrl_from_file, NVME_TARGET_PASSTHRU);

/*
 * Check we didn't inadvertently grow the command structure sizes:
 */
static inline void _nvme_check_size(void)
{
        BUILD_BUG_ON(sizeof(struct nvme_common_command) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_rw_command) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_identify) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_features) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_download_firmware) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_format_cmd) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_dsm_cmd) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_write_zeroes_cmd) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_abort_cmd) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_get_log_page_command) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_command) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_id_ctrl) != NVME_IDENTIFY_DATA_SIZE);
        BUILD_BUG_ON(sizeof(struct nvme_id_ns) != NVME_IDENTIFY_DATA_SIZE);
        BUILD_BUG_ON(sizeof(struct nvme_id_ns_zns) != NVME_IDENTIFY_DATA_SIZE);
        BUILD_BUG_ON(sizeof(struct nvme_id_ctrl_zns) != NVME_IDENTIFY_DATA_SIZE);
        BUILD_BUG_ON(sizeof(struct nvme_id_ctrl_nvm) != NVME_IDENTIFY_DATA_SIZE);
        BUILD_BUG_ON(sizeof(struct nvme_lba_range_type) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_smart_log) != 512);
        BUILD_BUG_ON(sizeof(struct nvme_dbbuf) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_directive_cmd) != 64);
}


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

        _nvme_check_size();

        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_ctrl_base_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_class->dev_uevent = nvme_class_uevent;

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

        result = alloc_chrdev_region(&nvme_ns_chr_devt, 0, NVME_MINORS,
                                     "nvme-generic");
        if (result < 0)
                goto destroy_subsys_class;

        nvme_ns_chr_class = class_create(THIS_MODULE, "nvme-generic");
        if (IS_ERR(nvme_ns_chr_class)) {
                result = PTR_ERR(nvme_ns_chr_class);
                goto unregister_generic_ns;
        }

        return 0;

unregister_generic_ns:
        unregister_chrdev_region(nvme_ns_chr_devt, NVME_MINORS);
destroy_subsys_class:
        class_destroy(nvme_subsys_class);
destroy_class:
        class_destroy(nvme_class);
unregister_chrdev:
        unregister_chrdev_region(nvme_ctrl_base_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;
}

static void __exit nvme_core_exit(void)
{
        class_destroy(nvme_ns_chr_class);
        class_destroy(nvme_subsys_class);
        class_destroy(nvme_class);
        unregister_chrdev_region(nvme_ns_chr_devt, NVME_MINORS);
        unregister_chrdev_region(nvme_ctrl_base_chr_devt, NVME_MINORS);
        destroy_workqueue(nvme_delete_wq);
        destroy_workqueue(nvme_reset_wq);
        destroy_workqueue(nvme_wq);
        ida_destroy(&nvme_ns_chr_minor_ida);
        ida_destroy(&nvme_instance_ida);
}

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