// 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/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/list_sort.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/pr.h>
#include <linux/ptrace.h>
#include <linux/nvme_ioctl.h>
#include <linux/t10-pi.h>
#include <linux/pm_qos.h>
#include <asm/unaligned.h>

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

/*
 * nvme_wq - hosts nvme related works that are not reset or delete
 * nvme_reset_wq - hosts nvme reset works
 * nvme_delete_wq - hosts nvme delete works
 *
 * nvme_wq will host works such 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_chr_devt;
static struct class *nvme_class;
static struct class *nvme_subsys_class;

static int nvme_revalidate_disk(struct gendisk *disk);
static void nvme_put_subsystem(struct nvme_subsystem *subsys);
static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
                                           unsigned nsid);

static void nvme_set_queue_dying(struct nvme_ns *ns)
{
        /*
         * Revalidating a dead namespace sets capacity to 0. This will end
         * buffered writers dirtying pages that can't be synced.
         */
        if (!ns->disk || test_and_set_bit(NVME_NS_DEAD, &ns->flags))
                return;
        blk_set_queue_dying(ns->queue);
        /* Forcibly unquiesce queues to avoid blocking dispatch */
        blk_mq_unquiesce_queue(ns->queue);
        /*
         * Revalidate after unblocking dispatchers that may be holding bd_butex
         */
        revalidate_disk(ns->disk);
}

static 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);

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;
}
EXPORT_SYMBOL_GPL(nvme_reset_ctrl_sync);

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

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

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

        /*
         * 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))
                ret = -EBUSY;
        if (!ret)
                nvme_do_delete_ctrl(ctrl);
        nvme_put_ctrl(ctrl);
        return ret;
}

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

static blk_status_t nvme_error_status(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;
        default:
                return BLK_STS_IOERR;
        }
}

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

static void nvme_retry_req(struct request *req)
{
        struct nvme_ns *ns = req->q->queuedata;
        unsigned long delay = 0;
        u16 crd;

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

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

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

        trace_nvme_complete_rq(req);

        nvme_cleanup_cmd(req);

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

        if (unlikely(status != BLK_STS_OK && nvme_req_needs_retry(req))) {
                if ((req->cmd_flags & REQ_NVME_MPATH) &&
                    blk_path_error(status)) {
                        nvme_failover_req(req);
                        return;
                }

                if (!blk_queue_dying(req->q)) {
                        nvme_retry_req(req);
                        return;
                }
        }

        nvme_trace_bio_complete(req, status);
        blk_mq_end_request(req, status);
}
EXPORT_SYMBOL_GPL(nvme_complete_rq);

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;
        blk_mq_complete_request(req);
        return true;
}
EXPORT_SYMBOL_GPL(nvme_cancel_request);

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

        spin_lock_irqsave(&ctrl->lock, flags);

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

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

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

/*
 * 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_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_simple_remove(&head->subsys->ns_ida, head->instance);
        list_del_init(&head->entry);
        cleanup_srcu_struct(&head->srcu);
        nvme_put_subsystem(head->subsys);
        kfree(head);
}

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

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

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

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

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

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

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

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

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

        return req;
}
EXPORT_SYMBOL_GPL(nvme_alloc_request);

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

static inline void nvme_setup_flush(struct nvme_ns *ns,
                struct nvme_command *cmnd)
{
        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;
        }

        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)
{
        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);
        cmnd->write_zeroes.control = 0;
        return BLK_STS_OK;
}

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

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

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

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

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

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

                switch (ns->pi_type) {
                case NVME_NS_DPS_PI_TYPE3:
                        control |= NVME_RW_PRINFO_PRCHK_GUARD;
                        break;
                case NVME_NS_DPS_PI_TYPE1:
                case NVME_NS_DPS_PI_TYPE2:
                        control |= NVME_RW_PRINFO_PRCHK_GUARD |
                                        NVME_RW_PRINFO_PRCHK_REF;
                        cmnd->rw.reftag = cpu_to_le32(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_ns *ns = req->rq_disk->private_data;
                struct page *page = req->special_vec.bv_page;

                if (page == ns->ctrl->discard_page)
                        clear_bit_unlock(0, &ns->ctrl->discard_page_busy);
                else
                        kfree(page_address(page) + req->special_vec.bv_offset);
        }
}
EXPORT_SYMBOL_GPL(nvme_cleanup_cmd);

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

        nvme_clear_nvme_request(req);

        memset(cmd, 0, sizeof(*cmd));
        switch (req_op(req)) {
        case REQ_OP_DRV_IN:
        case REQ_OP_DRV_OUT:
                memcpy(cmd, nvme_req(req)->cmd, sizeof(*cmd));
                break;
        case REQ_OP_FLUSH:
                nvme_setup_flush(ns, cmd);
                break;
        case REQ_OP_WRITE_ZEROES:
                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:
        case REQ_OP_WRITE:
                ret = nvme_setup_rw(ns, req, cmd);
                break;
        default:
                WARN_ON_ONCE(1);
                return BLK_STS_IOERR;
        }

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

static void nvme_end_sync_rq(struct request *rq, blk_status_t error)
{
        struct completion *waiting = rq->end_io_data;

        rq->end_io_data = NULL;
        complete(waiting);
}

static void nvme_execute_rq_polled(struct request_queue *q,
                struct gendisk *bd_disk, struct request *rq, int at_head)
{
        DECLARE_COMPLETION_ONSTACK(wait);

        WARN_ON_ONCE(!test_bit(QUEUE_FLAG_POLL, &q->queue_flags));

        rq->cmd_flags |= REQ_HIPRI;
        rq->end_io_data = &wait;
        blk_execute_rq_nowait(q, bd_disk, rq, at_head, nvme_end_sync_rq);

        while (!completion_done(&wait)) {
                blk_poll(q, request_to_qc_t(rq->mq_hctx, rq), true);
                cond_resched();
        }
}

/*
 * 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, bool poll)
{
        struct request *req;
        int ret;

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

        req->timeout = timeout ? timeout : ADMIN_TIMEOUT;

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

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

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

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

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

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

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

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

static int nvme_submit_user_cmd(struct request_queue *q,
                struct nvme_command *cmd, void __user *ubuffer,
                unsigned bufflen, void __user *meta_buffer, unsigned meta_len,
                u32 meta_seed, u64 *result, unsigned timeout)
{
        bool write = nvme_is_write(cmd);
        struct nvme_ns *ns = q->queuedata;
        struct gendisk *disk = ns ? ns->disk : NULL;
        struct request *req;
        struct bio *bio = NULL;
        void *meta = NULL;
        int ret;

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

        req->timeout = timeout ? timeout : ADMIN_TIMEOUT;
        nvme_req(req)->flags |= NVME_REQ_USERCMD;

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

        blk_execute_rq(req->q, disk, req, 0);
        if (nvme_req(req)->flags & NVME_REQ_CANCELLED)
                ret = -EINTR;
        else
                ret = nvme_req(req)->status;
        if (result)
                *result = le64_to_cpu(nvme_req(req)->result.u64);
        if (meta && !ret && !write) {
                if (copy_to_user(meta_buffer, meta, meta_len))
                        ret = -EFAULT;
        }
        kfree(meta);
 out_unmap:
        if (bio)
                blk_rq_unmap_user(bio);
 out:
        blk_mq_free_request(req);
        return ret;
}

static void nvme_keep_alive_end_io(struct request *rq, blk_status_t status)
{
        struct nvme_ctrl *ctrl = rq->end_io_data;
        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)
                queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ);
}

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

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

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

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

        return 0;
}

static void nvme_keep_alive_work(struct work_struct *work)
{

        struct nvme_ctrl *ctrl = container_of(to_delayed_work(work),
                        struct nvme_ctrl, ka_work);
        bool comp_seen = ctrl->comp_seen;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        memset(&c, 0, sizeof(c));
        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, false);
        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_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
{
        struct nvme_user_io io;
        struct nvme_command c;
        unsigned length, meta_len;
        void __user *metadata;

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

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

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

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

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

        return nvme_submit_user_cmd(ns->queue, &c,
                        (void __user *)(uintptr_t)io.addr, length,
                        metadata, meta_len, lower_32_bits(io.slba), NULL, 0);
}

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

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

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

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

        /*
         * For simplicity, IO to all namespaces is quiesced even if the command
         * effects say only one namespace is affected.
         */
        if (effects & (NVME_CMD_EFFECTS_LBCC | NVME_CMD_EFFECTS_CSE_MASK)) {
                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_update_formats(struct nvme_ctrl *ctrl)
{
        struct nvme_ns *ns;

        down_read(&ctrl->namespaces_rwsem);
        list_for_each_entry(ns, &ctrl->namespaces, list)
                if (ns->disk && nvme_revalidate_disk(ns->disk))
                        nvme_set_queue_dying(ns);
        up_read(&ctrl->namespaces_rwsem);
}

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

static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
                        struct nvme_passthru_cmd __user *ucmd)
{
        struct nvme_passthru_cmd cmd;
        struct nvme_command c;
        unsigned timeout = 0;
        u32 effects;
        u64 result;
        int status;

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

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

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

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

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

        return status;
}

static int nvme_user_cmd64(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
                        struct nvme_passthru_cmd64 __user *ucmd)
{
        struct nvme_passthru_cmd64 cmd;
        struct nvme_command c;
        unsigned timeout = 0;
        u32 effects;
        int status;

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

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

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

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

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

        return status;
}

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

                *head = disk->private_data;
                *srcu_idx = srcu_read_lock(&(*head)->srcu);
                ns = nvme_find_path(*head);
                if (!ns)
                        srcu_read_unlock(&(*head)->srcu, *srcu_idx);
                return ns;
        }
#endif
        *head = NULL;
        *srcu_idx = -1;
        return disk->private_data;
}

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

static bool is_ctrl_ioctl(unsigned int cmd)
{
        if (cmd == NVME_IOCTL_ADMIN_CMD || cmd == NVME_IOCTL_ADMIN64_CMD)
                return true;
        if (is_sed_ioctl(cmd))
                return true;
        return false;
}

static int nvme_handle_ctrl_ioctl(struct nvme_ns *ns, unsigned int cmd,
                                  void __user *argp,
                                  struct nvme_ns_head *head,
                                  int srcu_idx)
{
        struct nvme_ctrl *ctrl = ns->ctrl;
        int ret;

        nvme_get_ctrl(ns->ctrl);
        nvme_put_ns_from_disk(head, srcu_idx);

        switch (cmd) {
        case NVME_IOCTL_ADMIN_CMD:
                ret = nvme_user_cmd(ctrl, NULL, argp);
                break;
        case NVME_IOCTL_ADMIN64_CMD:
                ret = nvme_user_cmd64(ctrl, NULL, argp);
                break;
        default:
                ret = sed_ioctl(ctrl->opal_dev, cmd, argp);
                break;
        }
        nvme_put_ctrl(ctrl);
        return ret;
}

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

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

        /*
         * Handle ioctls that apply to the controller instead of the namespace
         * seperately and drop the ns SRCU reference early.  This avoids a
         * deadlock when deleting namespaces using the passthrough interface.
         */
        if (is_ctrl_ioctl(cmd))
                return nvme_handle_ctrl_ioctl(ns, cmd, argp, head, srcu_idx);

        switch (cmd) {
        case NVME_IOCTL_ID:
                force_successful_syscall_return();
                ret = ns->head->ns_id;
                break;
        case NVME_IOCTL_IO_CMD:
                ret = nvme_user_cmd(ns->ctrl, ns, argp);
                break;
        case NVME_IOCTL_SUBMIT_IO:
                ret = nvme_submit_io(ns, argp);
                break;
        case NVME_IOCTL_IO64_CMD:
                ret = nvme_user_cmd64(ns->ctrl, ns, argp);
                break;
        default:
                if (ns->ndev)
                        ret = nvme_nvm_ioctl(ns, cmd, arg);
                else
                        ret = -ENOTTY;
        }

        nvme_put_ns_from_disk(head, srcu_idx);
        return ret;
}

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

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

        return 0;

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

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

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

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

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

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

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

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->oncs & NVME_CTRL_ONCS_DSM)) {
                blk_queue_flag_clear(QUEUE_FLAG_DISCARD, queue);
                return;
        }

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

        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, UINT_MAX);
        blk_queue_max_discard_segments(queue, NVME_DSM_MAX_RANGES);

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

static void nvme_config_write_zeroes(struct gendisk *disk, struct nvme_ns *ns)
{
        u64 max_blocks;

        if (!(ns->ctrl->oncs & NVME_CTRL_ONCS_WRITE_ZEROES) ||
            (ns->ctrl->quirks & NVME_QUIRK_DISABLE_WRITE_ZEROES))
                return;
        /*
         * Even though NVMe spec explicitly states that MDTS is not
         * applicable to the write-zeroes:- "The restriction does not apply to
         * commands that do not transfer data between the host and the
         * controller (e.g., Write Uncorrectable ro Write Zeroes command).".
         * In order to be more cautious use controller's max_hw_sectors value
         * to configure the maximum sectors for the write-zeroes which is
         * configured based on the controller's MDTS field in the
         * nvme_init_identify() if available.
         */
        if (ns->ctrl->max_hw_sectors == UINT_MAX)
                max_blocks = (u64)USHRT_MAX + 1;
        else
                max_blocks = ns->ctrl->max_hw_sectors + 1;

        blk_queue_max_write_zeroes_sectors(disk->queue,
                                           nvme_lba_to_sect(ns, max_blocks));
}

static int nvme_report_ns_ids(struct nvme_ctrl *ctrl, unsigned int nsid,
                struct nvme_id_ns *id, struct nvme_ns_ids *ids)
{
        int ret = 0;

        memset(ids, 0, sizeof(*ids));

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

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

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

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

        if (ns->lba_shift > PAGE_SHIFT) {
                /* unsupported block size, set capacity to 0 later */
                bs = (1 << 9);
        }
        blk_mq_freeze_queue(disk->queue);
        blk_integrity_unregister(disk);

        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 & (1 << 1) && id->nawupf)
                        atomic_bs = (1 + le16_to_cpu(id->nawupf)) * bs;
                else
                        atomic_bs = (1 + ns->ctrl->subsys->awupf) * bs;
        } else {
                atomic_bs = bs;
        }
        phys_bs = bs;
        io_opt = bs;
        if (id->nsfeat & (1 << 4)) {
                /* NPWG = Namespace Preferred Write Granularity */
                phys_bs *= 1 + le16_to_cpu(id->npwg);
                /* NOWS = Namespace Optimal Write Size */
                io_opt *= 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);

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

        set_capacity(disk, capacity);

        nvme_config_discard(disk, ns);
        nvme_config_write_zeroes(disk, ns);

        if (id->nsattr & (1 << 0))
                set_disk_ro(disk, true);
        else
                set_disk_ro(disk, false);

        blk_mq_unfreeze_queue(disk->queue);
}

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

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

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

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

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

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

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

        __nvme_revalidate_disk(disk, id);
        ret = nvme_report_ns_ids(ctrl, ns->head->ns_id, id, &ids);
        if (ret)
                goto free_id;

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

free_id:
        kfree(id);
out:
        /*
         * Only fail the function if we got a fatal error back from the
         * device, otherwise ignore the error and just move on.
         */
        if (ret == -ENOMEM || (ret > 0 && !(ret & NVME_SC_DNR)))
                ret = 0;
        else if (ret > 0)
                ret = blk_status_to_errno(nvme_error_status(ret));
        return ret;
}

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

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

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

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

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

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

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

        if (flags & ~PR_FL_IGNORE_KEY)
                return -EOPNOTSUPP;

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

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

        if (flags & ~PR_FL_IGNORE_KEY)
                return -EOPNOTSUPP;

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

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

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

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

static const struct pr_ops nvme_pr_ops = {
        .pr_register    = nvme_pr_register,
        .pr_reserve     = nvme_pr_reserve,
        .pr_release     = nvme_pr_release,

        .pr_preempt     = nvme_pr_preempt,
        .pr_clear       = nvme_pr_clear,
};

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

        memset(&cmd, 0, sizeof(cmd));
        if (send)
                cmd.common.opcode = nvme_admin_security_send;
        else
                cmd.common.opcode = nvme_admin_security_recv;
        cmd.common.nsid = 0;
        cmd.common.cdw10 = 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,
                                      ADMIN_TIMEOUT, NVME_QID_ANY, 1, 0, false);
}
EXPORT_SYMBOL_GPL(nvme_sec_submit);
#endif /* CONFIG_BLK_SED_OPAL */

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

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

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

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

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

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

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

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

        return ret;
}

/*
 * If the device has been passed off to us in an enabled state, just clear
 * the enabled bit.  The spec says we should set the 'shutdown notification
 * bits', but doing so may cause the device to complete commands to the
 * admin queue ... and we don't know what memory that might be pointing at!
 */
int nvme_disable_ctrl(struct nvme_ctrl *ctrl)
{
        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)
{
        /*
         * Default to a 4K page size, with the intention to update this
         * path in the future to accomodate architectures with differing
         * kernel and IO page sizes.
         */
        unsigned dev_page_min, page_shift = 12;
        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 (page_shift < dev_page_min) {
                dev_err(ctrl->device,
                        "Minimum device page size %u too large for host (%u)\n",
                        1 << dev_page_min, 1 << page_shift);
                return -ENODEV;
        }

        ctrl->page_size = 1 << page_shift;

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

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

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

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

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

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

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

        return ret;
}
EXPORT_SYMBOL_GPL(nvme_shutdown_ctrl);

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

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

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

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

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

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

static int nvme_configure_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;
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

                        if (total_latency_us > max_lat_us)
                                max_lat_us = total_latency_us;
                }

                apste = 1;

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

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

        kfree(table);
        return ret;
}

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

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

        default:
                latency = val;
        }

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

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

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

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

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

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

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

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

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

static 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 (tmp->state == NVME_CTRL_DELETING ||
                    tmp->state == NVME_CTRL_DEAD)
                        continue;

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

                if ((id->cmic & (1 << 1)) ||
                    (ctrl->opts && ctrl->opts->discovery_nqn))
                        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;
        subsys->awupf = le16_to_cpu(id->awupf);
#ifdef CONFIG_NVME_MULTIPATH
        subsys->iopolicy = NVME_IOPOLICY_NUMA;
#endif

        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,
                void *log, size_t size, u64 offset)
{
        struct nvme_command c = { };
        unsigned long dwlen = size / 4 - 1;

        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));

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

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

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

        if (!ctrl->effects)
                return 0;

        ret = nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_CMD_EFFECTS, 0,
                        ctrl->effects, sizeof(*ctrl->effects), 0);
        if (ret) {
                kfree(ctrl->effects);
                ctrl->effects = NULL;
        }
        return ret;
}

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

        ret = ctrl->ops->reg_read32(ctrl, NVME_REG_VS, &ctrl->vs);
        if (ret) {
                dev_err(ctrl->device, "Reading VS failed (%d)\n", ret);
                return ret;
        }
        page_shift = NVME_CAP_MPSMIN(ctrl->cap) + 12;
        ctrl->sqsize = min_t(int, NVME_CAP_MQES(ctrl->cap), ctrl->sqsize);

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

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

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

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

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

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

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

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

        ctrl->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 = 1 << (id->mdts + page_shift - 9);
        else
                max_hw_sectors = UINT_MAX;
        ctrl->max_hw_sectors =
                min_not_zero(ctrl->max_hw_sectors, max_hw_sectors);

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

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

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

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

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

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

                /*
                 * In fabrics we need to verify the cntlid matches the
                 * admin connect
                 */
                if (ctrl->cntlid != le16_to_cpu(id->cntlid)) {
                        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 (!ctrl->opts->discovery_nqn && !ctrl->kas) {
                        dev_err(ctrl->device,
                                "keep-alive support is mandatory for fabrics\n");
                        ret = -EINVAL;
                        goto out_free;
                }
        } else {
                ctrl->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(ctrl, id);
        kfree(id);

        if (ret < 0)
                return ret;

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

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

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

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

        if (!ctrl->identified)
                nvme_hwmon_init(ctrl);

        ctrl->identified = true;

        return 0;

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

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

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

        file->private_data = ctrl;
        return 0;
}

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

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

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

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

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

out_unlock:
        up_read(&ctrl->namespaces_rwsem);
        return ret;
}

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

        switch (cmd) {
        case NVME_IOCTL_ADMIN_CMD:
                return nvme_user_cmd(ctrl, NULL, argp);
        case NVME_IOCTL_ADMIN64_CMD:
                return nvme_user_cmd64(ctrl, NULL, argp);
        case NVME_IOCTL_IO_CMD:
                return nvme_dev_user_cmd(ctrl, argp);
        case NVME_IOCTL_RESET:
                dev_warn(ctrl->device, "resetting controller\n");
                return nvme_reset_ctrl_sync(ctrl);
        case NVME_IOCTL_SUBSYS_RESET:
                return nvme_reset_subsystem(ctrl);
        case NVME_IOCTL_RESCAN:
                nvme_queue_scan(ctrl);
                return 0;
        default:
                return -ENOTTY;
        }
}

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