Merge 4.14.23 into android-4.14

[GitHub/LineageOS/android_kernel_motorola_exynos9610.git] / drivers / nvme / host / fabrics.c

/*
 * NVMe over Fabrics common host code.
 * Copyright (c) 2015-2016 HGST, a Western Digital Company.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/parser.h>
#include <linux/seq_file.h>
#include "nvme.h"
#include "fabrics.h"

static LIST_HEAD(nvmf_transports);
static DECLARE_RWSEM(nvmf_transports_rwsem);

static LIST_HEAD(nvmf_hosts);
static DEFINE_MUTEX(nvmf_hosts_mutex);

static struct nvmf_host *nvmf_default_host;

static struct nvmf_host *__nvmf_host_find(const char *hostnqn)
{
        struct nvmf_host *host;

        list_for_each_entry(host, &nvmf_hosts, list) {
                if (!strcmp(host->nqn, hostnqn))
                        return host;
        }

        return NULL;
}

static struct nvmf_host *nvmf_host_add(const char *hostnqn)
{
        struct nvmf_host *host;

        mutex_lock(&nvmf_hosts_mutex);
        host = __nvmf_host_find(hostnqn);
        if (host) {
                kref_get(&host->ref);
                goto out_unlock;
        }

        host = kmalloc(sizeof(*host), GFP_KERNEL);
        if (!host)
                goto out_unlock;

        kref_init(&host->ref);
        memcpy(host->nqn, hostnqn, NVMF_NQN_SIZE);

        list_add_tail(&host->list, &nvmf_hosts);
out_unlock:
        mutex_unlock(&nvmf_hosts_mutex);
        return host;
}

static struct nvmf_host *nvmf_host_default(void)
{
        struct nvmf_host *host;

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

        kref_init(&host->ref);
        snprintf(host->nqn, NVMF_NQN_SIZE,
                "nqn.2014-08.org.nvmexpress:uuid:%pUb", &host->id);

        mutex_lock(&nvmf_hosts_mutex);
        list_add_tail(&host->list, &nvmf_hosts);
        mutex_unlock(&nvmf_hosts_mutex);

        return host;
}

static void nvmf_host_destroy(struct kref *ref)
{
        struct nvmf_host *host = container_of(ref, struct nvmf_host, ref);

        mutex_lock(&nvmf_hosts_mutex);
        list_del(&host->list);
        mutex_unlock(&nvmf_hosts_mutex);

        kfree(host);
}

static void nvmf_host_put(struct nvmf_host *host)
{
        if (host)
                kref_put(&host->ref, nvmf_host_destroy);
}

/**
 * nvmf_get_address() -  Get address/port
 * @ctrl:       Host NVMe controller instance which we got the address
 * @buf:        OUTPUT parameter that will contain the address/port
 * @size:       buffer size
 */
int nvmf_get_address(struct nvme_ctrl *ctrl, char *buf, int size)
{
        int len = 0;

        if (ctrl->opts->mask & NVMF_OPT_TRADDR)
                len += snprintf(buf, size, "traddr=%s", ctrl->opts->traddr);
        if (ctrl->opts->mask & NVMF_OPT_TRSVCID)
                len += snprintf(buf + len, size - len, "%strsvcid=%s",
                                (len) ? "," : "", ctrl->opts->trsvcid);
        if (ctrl->opts->mask & NVMF_OPT_HOST_TRADDR)
                len += snprintf(buf + len, size - len, "%shost_traddr=%s",
                                (len) ? "," : "", ctrl->opts->host_traddr);
        len += snprintf(buf + len, size - len, "\n");

        return len;
}
EXPORT_SYMBOL_GPL(nvmf_get_address);

/**
 * nvmf_reg_read32() -  NVMe Fabrics "Property Get" API function.
 * @ctrl:       Host NVMe controller instance maintaining the admin
 *              queue used to submit the property read command to
 *              the allocated NVMe controller resource on the target system.
 * @off:        Starting offset value of the targeted property
 *              register (see the fabrics section of the NVMe standard).
 * @val:        OUTPUT parameter that will contain the value of
 *              the property after a successful read.
 *
 * Used by the host system to retrieve a 32-bit capsule property value
 * from an NVMe controller on the target system.
 *
 * ("Capsule property" is an "PCIe register concept" applied to the
 * NVMe fabrics space.)
 *
 * Return:
 *      0: successful read
 *      > 0: NVMe error status code
 *      < 0: Linux errno error code
 */
int nvmf_reg_read32(struct nvme_ctrl *ctrl, u32 off, u32 *val)
{
        struct nvme_command cmd;
        union nvme_result res;
        int ret;

        memset(&cmd, 0, sizeof(cmd));
        cmd.prop_get.opcode = nvme_fabrics_command;
        cmd.prop_get.fctype = nvme_fabrics_type_property_get;
        cmd.prop_get.offset = cpu_to_le32(off);

        ret = __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, &res, NULL, 0, 0,
                        NVME_QID_ANY, 0, 0);

        if (ret >= 0)
                *val = le64_to_cpu(res.u64);
        if (unlikely(ret != 0))
                dev_err(ctrl->device,
                        "Property Get error: %d, offset %#x\n",
                        ret > 0 ? ret & ~NVME_SC_DNR : ret, off);

        return ret;
}
EXPORT_SYMBOL_GPL(nvmf_reg_read32);

/**
 * nvmf_reg_read64() -  NVMe Fabrics "Property Get" API function.
 * @ctrl:       Host NVMe controller instance maintaining the admin
 *              queue used to submit the property read command to
 *              the allocated controller resource on the target system.
 * @off:        Starting offset value of the targeted property
 *              register (see the fabrics section of the NVMe standard).
 * @val:        OUTPUT parameter that will contain the value of
 *              the property after a successful read.
 *
 * Used by the host system to retrieve a 64-bit capsule property value
 * from an NVMe controller on the target system.
 *
 * ("Capsule property" is an "PCIe register concept" applied to the
 * NVMe fabrics space.)
 *
 * Return:
 *      0: successful read
 *      > 0: NVMe error status code
 *      < 0: Linux errno error code
 */
int nvmf_reg_read64(struct nvme_ctrl *ctrl, u32 off, u64 *val)
{
        struct nvme_command cmd;
        union nvme_result res;
        int ret;

        memset(&cmd, 0, sizeof(cmd));
        cmd.prop_get.opcode = nvme_fabrics_command;
        cmd.prop_get.fctype = nvme_fabrics_type_property_get;
        cmd.prop_get.attrib = 1;
        cmd.prop_get.offset = cpu_to_le32(off);

        ret = __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, &res, NULL, 0, 0,
                        NVME_QID_ANY, 0, 0);

        if (ret >= 0)
                *val = le64_to_cpu(res.u64);
        if (unlikely(ret != 0))
                dev_err(ctrl->device,
                        "Property Get error: %d, offset %#x\n",
                        ret > 0 ? ret & ~NVME_SC_DNR : ret, off);
        return ret;
}
EXPORT_SYMBOL_GPL(nvmf_reg_read64);

/**
 * nvmf_reg_write32() -  NVMe Fabrics "Property Write" API function.
 * @ctrl:       Host NVMe controller instance maintaining the admin
 *              queue used to submit the property read command to
 *              the allocated NVMe controller resource on the target system.
 * @off:        Starting offset value of the targeted property
 *              register (see the fabrics section of the NVMe standard).
 * @val:        Input parameter that contains the value to be
 *              written to the property.
 *
 * Used by the NVMe host system to write a 32-bit capsule property value
 * to an NVMe controller on the target system.
 *
 * ("Capsule property" is an "PCIe register concept" applied to the
 * NVMe fabrics space.)
 *
 * Return:
 *      0: successful write
 *      > 0: NVMe error status code
 *      < 0: Linux errno error code
 */
int nvmf_reg_write32(struct nvme_ctrl *ctrl, u32 off, u32 val)
{
        struct nvme_command cmd;
        int ret;

        memset(&cmd, 0, sizeof(cmd));
        cmd.prop_set.opcode = nvme_fabrics_command;
        cmd.prop_set.fctype = nvme_fabrics_type_property_set;
        cmd.prop_set.attrib = 0;
        cmd.prop_set.offset = cpu_to_le32(off);
        cmd.prop_set.value = cpu_to_le64(val);

        ret = __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, NULL, NULL, 0, 0,
                        NVME_QID_ANY, 0, 0);
        if (unlikely(ret))
                dev_err(ctrl->device,
                        "Property Set error: %d, offset %#x\n",
                        ret > 0 ? ret & ~NVME_SC_DNR : ret, off);
        return ret;
}
EXPORT_SYMBOL_GPL(nvmf_reg_write32);

/**
 * nvmf_log_connect_error() - Error-parsing-diagnostic print
 * out function for connect() errors.
 *
 * @ctrl: the specific /dev/nvmeX device that had the error.
 *
 * @errval: Error code to be decoded in a more human-friendly
 *          printout.
 *
 * @offset: For use with the NVMe error code NVME_SC_CONNECT_INVALID_PARAM.
 *
 * @cmd: This is the SQE portion of a submission capsule.
 *
 * @data: This is the "Data" portion of a submission capsule.
 */
static void nvmf_log_connect_error(struct nvme_ctrl *ctrl,
                int errval, int offset, struct nvme_command *cmd,
                struct nvmf_connect_data *data)
{
        int err_sctype = errval & (~NVME_SC_DNR);

        switch (err_sctype) {

        case (NVME_SC_CONNECT_INVALID_PARAM):
                if (offset >> 16) {
                        char *inv_data = "Connect Invalid Data Parameter";

                        switch (offset & 0xffff) {
                        case (offsetof(struct nvmf_connect_data, cntlid)):
                                dev_err(ctrl->device,
                                        "%s, cntlid: %d\n",
                                        inv_data, data->cntlid);
                                break;
                        case (offsetof(struct nvmf_connect_data, hostnqn)):
                                dev_err(ctrl->device,
                                        "%s, hostnqn \"%s\"\n",
                                        inv_data, data->hostnqn);
                                break;
                        case (offsetof(struct nvmf_connect_data, subsysnqn)):
                                dev_err(ctrl->device,
                                        "%s, subsysnqn \"%s\"\n",
                                        inv_data, data->subsysnqn);
                                break;
                        default:
                                dev_err(ctrl->device,
                                        "%s, starting byte offset: %d\n",
                                       inv_data, offset & 0xffff);
                                break;
                        }
                } else {
                        char *inv_sqe = "Connect Invalid SQE Parameter";

                        switch (offset) {
                        case (offsetof(struct nvmf_connect_command, qid)):
                                dev_err(ctrl->device,
                                       "%s, qid %d\n",
                                        inv_sqe, cmd->connect.qid);
                                break;
                        default:
                                dev_err(ctrl->device,
                                        "%s, starting byte offset: %d\n",
                                        inv_sqe, offset);
                        }
                }
                break;

        case NVME_SC_CONNECT_INVALID_HOST:
                dev_err(ctrl->device,
                        "Connect for subsystem %s is not allowed, hostnqn: %s\n",
                        data->subsysnqn, data->hostnqn);
                break;

        case NVME_SC_CONNECT_CTRL_BUSY:
                dev_err(ctrl->device,
                        "Connect command failed: controller is busy or not available\n");
                break;

        case NVME_SC_CONNECT_FORMAT:
                dev_err(ctrl->device,
                        "Connect incompatible format: %d",
                        cmd->connect.recfmt);
                break;

        default:
                dev_err(ctrl->device,
                        "Connect command failed, error wo/DNR bit: %d\n",
                        err_sctype);
                break;
        } /* switch (err_sctype) */
}

/**
 * nvmf_connect_admin_queue() - NVMe Fabrics Admin Queue "Connect"
 *                              API function.
 * @ctrl:       Host nvme controller instance used to request
 *              a new NVMe controller allocation on the target
 *              system and  establish an NVMe Admin connection to
 *              that controller.
 *
 * This function enables an NVMe host device to request a new allocation of
 * an NVMe controller resource on a target system as well establish a
 * fabrics-protocol connection of the NVMe Admin queue between the
 * host system device and the allocated NVMe controller on the
 * target system via a NVMe Fabrics "Connect" command.
 *
 * Return:
 *      0: success
 *      > 0: NVMe error status code
 *      < 0: Linux errno error code
 *
 */
int nvmf_connect_admin_queue(struct nvme_ctrl *ctrl)
{
        struct nvme_command cmd;
        union nvme_result res;
        struct nvmf_connect_data *data;
        int ret;

        memset(&cmd, 0, sizeof(cmd));
        cmd.connect.opcode = nvme_fabrics_command;
        cmd.connect.fctype = nvme_fabrics_type_connect;
        cmd.connect.qid = 0;
        cmd.connect.sqsize = cpu_to_le16(NVME_AQ_DEPTH - 1);

        /*
         * Set keep-alive timeout in seconds granularity (ms * 1000)
         * and add a grace period for controller kato enforcement
         */
        cmd.connect.kato = ctrl->opts->discovery_nqn ? 0 :
                cpu_to_le32((ctrl->kato + NVME_KATO_GRACE) * 1000);

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

        uuid_copy(&data->hostid, &ctrl->opts->host->id);
        data->cntlid = cpu_to_le16(0xffff);
        strncpy(data->subsysnqn, ctrl->opts->subsysnqn, NVMF_NQN_SIZE);
        strncpy(data->hostnqn, ctrl->opts->host->nqn, NVMF_NQN_SIZE);

        ret = __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, &res,
                        data, sizeof(*data), 0, NVME_QID_ANY, 1,
                        BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT);
        if (ret) {
                nvmf_log_connect_error(ctrl, ret, le32_to_cpu(res.u32),
                                       &cmd, data);
                goto out_free_data;
        }

        ctrl->cntlid = le16_to_cpu(res.u16);

out_free_data:
        kfree(data);
        return ret;
}
EXPORT_SYMBOL_GPL(nvmf_connect_admin_queue);

/**
 * nvmf_connect_io_queue() - NVMe Fabrics I/O Queue "Connect"
 *                           API function.
 * @ctrl:       Host nvme controller instance used to establish an
 *              NVMe I/O queue connection to the already allocated NVMe
 *              controller on the target system.
 * @qid:        NVMe I/O queue number for the new I/O connection between
 *              host and target (note qid == 0 is illegal as this is
 *              the Admin queue, per NVMe standard).
 *
 * This function issues a fabrics-protocol connection
 * of a NVMe I/O queue (via NVMe Fabrics "Connect" command)
 * between the host system device and the allocated NVMe controller
 * on the target system.
 *
 * Return:
 *      0: success
 *      > 0: NVMe error status code
 *      < 0: Linux errno error code
 */
int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid)
{
        struct nvme_command cmd;
        struct nvmf_connect_data *data;
        union nvme_result res;
        int ret;

        memset(&cmd, 0, sizeof(cmd));
        cmd.connect.opcode = nvme_fabrics_command;
        cmd.connect.fctype = nvme_fabrics_type_connect;
        cmd.connect.qid = cpu_to_le16(qid);
        cmd.connect.sqsize = cpu_to_le16(ctrl->sqsize);

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

        uuid_copy(&data->hostid, &ctrl->opts->host->id);
        data->cntlid = cpu_to_le16(ctrl->cntlid);
        strncpy(data->subsysnqn, ctrl->opts->subsysnqn, NVMF_NQN_SIZE);
        strncpy(data->hostnqn, ctrl->opts->host->nqn, NVMF_NQN_SIZE);

        ret = __nvme_submit_sync_cmd(ctrl->connect_q, &cmd, &res,
                        data, sizeof(*data), 0, qid, 1,
                        BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT);
        if (ret) {
                nvmf_log_connect_error(ctrl, ret, le32_to_cpu(res.u32),
                                       &cmd, data);
        }
        kfree(data);
        return ret;
}
EXPORT_SYMBOL_GPL(nvmf_connect_io_queue);

bool nvmf_should_reconnect(struct nvme_ctrl *ctrl)
{
        if (ctrl->opts->max_reconnects != -1 &&
            ctrl->nr_reconnects < ctrl->opts->max_reconnects)
                return true;

        return false;
}
EXPORT_SYMBOL_GPL(nvmf_should_reconnect);

/**
 * nvmf_register_transport() - NVMe Fabrics Library registration function.
 * @ops:        Transport ops instance to be registered to the
 *              common fabrics library.
 *
 * API function that registers the type of specific transport fabric
 * being implemented to the common NVMe fabrics library. Part of
 * the overall init sequence of starting up a fabrics driver.
 */
int nvmf_register_transport(struct nvmf_transport_ops *ops)
{
        if (!ops->create_ctrl)
                return -EINVAL;

        down_write(&nvmf_transports_rwsem);
        list_add_tail(&ops->entry, &nvmf_transports);
        up_write(&nvmf_transports_rwsem);

        return 0;
}
EXPORT_SYMBOL_GPL(nvmf_register_transport);

/**
 * nvmf_unregister_transport() - NVMe Fabrics Library unregistration function.
 * @ops:        Transport ops instance to be unregistered from the
 *              common fabrics library.
 *
 * Fabrics API function that unregisters the type of specific transport
 * fabric being implemented from the common NVMe fabrics library.
 * Part of the overall exit sequence of unloading the implemented driver.
 */
void nvmf_unregister_transport(struct nvmf_transport_ops *ops)
{
        down_write(&nvmf_transports_rwsem);
        list_del(&ops->entry);
        up_write(&nvmf_transports_rwsem);
}
EXPORT_SYMBOL_GPL(nvmf_unregister_transport);

static struct nvmf_transport_ops *nvmf_lookup_transport(
                struct nvmf_ctrl_options *opts)
{
        struct nvmf_transport_ops *ops;

        lockdep_assert_held(&nvmf_transports_rwsem);

        list_for_each_entry(ops, &nvmf_transports, entry) {
                if (strcmp(ops->name, opts->transport) == 0)
                        return ops;
        }

        return NULL;
}

static const match_table_t opt_tokens = {
        { NVMF_OPT_TRANSPORT,           "transport=%s"          },
        { NVMF_OPT_TRADDR,              "traddr=%s"             },
        { NVMF_OPT_TRSVCID,             "trsvcid=%s"            },
        { NVMF_OPT_NQN,                 "nqn=%s"                },
        { NVMF_OPT_QUEUE_SIZE,          "queue_size=%d"         },
        { NVMF_OPT_NR_IO_QUEUES,        "nr_io_queues=%d"       },
        { NVMF_OPT_RECONNECT_DELAY,     "reconnect_delay=%d"    },
        { NVMF_OPT_CTRL_LOSS_TMO,       "ctrl_loss_tmo=%d"      },
        { NVMF_OPT_KATO,                "keep_alive_tmo=%d"     },
        { NVMF_OPT_HOSTNQN,             "hostnqn=%s"            },
        { NVMF_OPT_HOST_TRADDR,         "host_traddr=%s"        },
        { NVMF_OPT_HOST_ID,             "hostid=%s"             },
        { NVMF_OPT_ERR,                 NULL                    }
};

static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
                const char *buf)
{
        substring_t args[MAX_OPT_ARGS];
        char *options, *o, *p;
        int token, ret = 0;
        size_t nqnlen  = 0;
        int ctrl_loss_tmo = NVMF_DEF_CTRL_LOSS_TMO;
        uuid_t hostid;

        /* Set defaults */
        opts->queue_size = NVMF_DEF_QUEUE_SIZE;
        opts->nr_io_queues = num_online_cpus();
        opts->reconnect_delay = NVMF_DEF_RECONNECT_DELAY;
        opts->kato = NVME_DEFAULT_KATO;

        options = o = kstrdup(buf, GFP_KERNEL);
        if (!options)
                return -ENOMEM;

        uuid_gen(&hostid);

        while ((p = strsep(&o, ",\n")) != NULL) {
                if (!*p)
                        continue;

                token = match_token(p, opt_tokens, args);
                opts->mask |= token;
                switch (token) {
                case NVMF_OPT_TRANSPORT:
                        p = match_strdup(args);
                        if (!p) {
                                ret = -ENOMEM;
                                goto out;
                        }
                        opts->transport = p;
                        break;
                case NVMF_OPT_NQN:
                        p = match_strdup(args);
                        if (!p) {
                                ret = -ENOMEM;
                                goto out;
                        }
                        opts->subsysnqn = p;
                        nqnlen = strlen(opts->subsysnqn);
                        if (nqnlen >= NVMF_NQN_SIZE) {
                                pr_err("%s needs to be < %d bytes\n",
                                        opts->subsysnqn, NVMF_NQN_SIZE);
                                ret = -EINVAL;
                                goto out;
                        }
                        opts->discovery_nqn =
                                !(strcmp(opts->subsysnqn,
                                         NVME_DISC_SUBSYS_NAME));
                        if (opts->discovery_nqn)
                                opts->nr_io_queues = 0;
                        break;
                case NVMF_OPT_TRADDR:
                        p = match_strdup(args);
                        if (!p) {
                                ret = -ENOMEM;
                                goto out;
                        }
                        opts->traddr = p;
                        break;
                case NVMF_OPT_TRSVCID:
                        p = match_strdup(args);
                        if (!p) {
                                ret = -ENOMEM;
                                goto out;
                        }
                        opts->trsvcid = p;
                        break;
                case NVMF_OPT_QUEUE_SIZE:
                        if (match_int(args, &token)) {
                                ret = -EINVAL;
                                goto out;
                        }
                        if (token < NVMF_MIN_QUEUE_SIZE ||
                            token > NVMF_MAX_QUEUE_SIZE) {
                                pr_err("Invalid queue_size %d\n", token);
                                ret = -EINVAL;
                                goto out;
                        }
                        opts->queue_size = token;
                        break;
                case NVMF_OPT_NR_IO_QUEUES:
                        if (match_int(args, &token)) {
                                ret = -EINVAL;
                                goto out;
                        }
                        if (token <= 0) {
                                pr_err("Invalid number of IOQs %d\n", token);
                                ret = -EINVAL;
                                goto out;
                        }
                        opts->nr_io_queues = min_t(unsigned int,
                                        num_online_cpus(), token);
                        break;
                case NVMF_OPT_KATO:
                        if (match_int(args, &token)) {
                                ret = -EINVAL;
                                goto out;
                        }

                        if (token < 0) {
                                pr_err("Invalid keep_alive_tmo %d\n", token);
                                ret = -EINVAL;
                                goto out;
                        } else if (token == 0 && !opts->discovery_nqn) {
                                /* Allowed for debug */
                                pr_warn("keep_alive_tmo 0 won't execute keep alives!!!\n");
                        }
                        opts->kato = token;

                        if (opts->discovery_nqn && opts->kato) {
                                pr_err("Discovery controllers cannot accept KATO != 0\n");
                                ret = -EINVAL;
                                goto out;
                        }

                        break;
                case NVMF_OPT_CTRL_LOSS_TMO:
                        if (match_int(args, &token)) {
                                ret = -EINVAL;
                                goto out;
                        }

                        if (token < 0)
                                pr_warn("ctrl_loss_tmo < 0 will reconnect forever\n");
                        ctrl_loss_tmo = token;
                        break;
                case NVMF_OPT_HOSTNQN:
                        if (opts->host) {
                                pr_err("hostnqn already user-assigned: %s\n",
                                       opts->host->nqn);
                                ret = -EADDRINUSE;
                                goto out;
                        }
                        p = match_strdup(args);
                        if (!p) {
                                ret = -ENOMEM;
                                goto out;
                        }
                        nqnlen = strlen(p);
                        if (nqnlen >= NVMF_NQN_SIZE) {
                                pr_err("%s needs to be < %d bytes\n",
                                        p, NVMF_NQN_SIZE);
                                kfree(p);
                                ret = -EINVAL;
                                goto out;
                        }
                        opts->host = nvmf_host_add(p);
                        kfree(p);
                        if (!opts->host) {
                                ret = -ENOMEM;
                                goto out;
                        }
                        break;
                case NVMF_OPT_RECONNECT_DELAY:
                        if (match_int(args, &token)) {
                                ret = -EINVAL;
                                goto out;
                        }
                        if (token <= 0) {
                                pr_err("Invalid reconnect_delay %d\n", token);
                                ret = -EINVAL;
                                goto out;
                        }
                        opts->reconnect_delay = token;
                        break;
                case NVMF_OPT_HOST_TRADDR:
                        p = match_strdup(args);
                        if (!p) {
                                ret = -ENOMEM;
                                goto out;
                        }
                        opts->host_traddr = p;
                        break;
                case NVMF_OPT_HOST_ID:
                        p = match_strdup(args);
                        if (!p) {
                                ret = -ENOMEM;
                                goto out;
                        }
                        if (uuid_parse(p, &hostid)) {
                                pr_err("Invalid hostid %s\n", p);
                                ret = -EINVAL;
                                goto out;
                        }
                        break;
                default:
                        pr_warn("unknown parameter or missing value '%s' in ctrl creation request\n",
                                p);
                        ret = -EINVAL;
                        goto out;
                }
        }

        if (ctrl_loss_tmo < 0)
                opts->max_reconnects = -1;
        else
                opts->max_reconnects = DIV_ROUND_UP(ctrl_loss_tmo,
                                                opts->reconnect_delay);

        if (!opts->host) {
                kref_get(&nvmf_default_host->ref);
                opts->host = nvmf_default_host;
        }

        uuid_copy(&opts->host->id, &hostid);

out:
        kfree(options);
        return ret;
}

static int nvmf_check_required_opts(struct nvmf_ctrl_options *opts,
                unsigned int required_opts)
{
        if ((opts->mask & required_opts) != required_opts) {
                int i;

                for (i = 0; i < ARRAY_SIZE(opt_tokens); i++) {
                        if ((opt_tokens[i].token & required_opts) &&
                            !(opt_tokens[i].token & opts->mask)) {
                                pr_warn("missing parameter '%s'\n",
                                        opt_tokens[i].pattern);
                        }
                }

                return -EINVAL;
        }

        return 0;
}

static int nvmf_check_allowed_opts(struct nvmf_ctrl_options *opts,
                unsigned int allowed_opts)
{
        if (opts->mask & ~allowed_opts) {
                int i;

                for (i = 0; i < ARRAY_SIZE(opt_tokens); i++) {
                        if ((opt_tokens[i].token & opts->mask) &&
                            (opt_tokens[i].token & ~allowed_opts)) {
                                pr_warn("invalid parameter '%s'\n",
                                        opt_tokens[i].pattern);
                        }
                }

                return -EINVAL;
        }

        return 0;
}

void nvmf_free_options(struct nvmf_ctrl_options *opts)
{
        nvmf_host_put(opts->host);
        kfree(opts->transport);
        kfree(opts->traddr);
        kfree(opts->trsvcid);
        kfree(opts->subsysnqn);
        kfree(opts->host_traddr);
        kfree(opts);
}
EXPORT_SYMBOL_GPL(nvmf_free_options);

#define NVMF_REQUIRED_OPTS      (NVMF_OPT_TRANSPORT | NVMF_OPT_NQN)
#define NVMF_ALLOWED_OPTS       (NVMF_OPT_QUEUE_SIZE | NVMF_OPT_NR_IO_QUEUES | \
                                 NVMF_OPT_KATO | NVMF_OPT_HOSTNQN | \
                                 NVMF_OPT_HOST_ID)

static struct nvme_ctrl *
nvmf_create_ctrl(struct device *dev, const char *buf, size_t count)
{
        struct nvmf_ctrl_options *opts;
        struct nvmf_transport_ops *ops;
        struct nvme_ctrl *ctrl;
        int ret;

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

        ret = nvmf_parse_options(opts, buf);
        if (ret)
                goto out_free_opts;

        /*
         * Check the generic options first as we need a valid transport for
         * the lookup below.  Then clear the generic flags so that transport
         * drivers don't have to care about them.
         */
        ret = nvmf_check_required_opts(opts, NVMF_REQUIRED_OPTS);
        if (ret)
                goto out_free_opts;
        opts->mask &= ~NVMF_REQUIRED_OPTS;

        down_read(&nvmf_transports_rwsem);
        ops = nvmf_lookup_transport(opts);
        if (!ops) {
                pr_info("no handler found for transport %s.\n",
                        opts->transport);
                ret = -EINVAL;
                goto out_unlock;
        }

        ret = nvmf_check_required_opts(opts, ops->required_opts);
        if (ret)
                goto out_unlock;
        ret = nvmf_check_allowed_opts(opts, NVMF_ALLOWED_OPTS |
                                ops->allowed_opts | ops->required_opts);
        if (ret)
                goto out_unlock;

        ctrl = ops->create_ctrl(dev, opts);
        if (IS_ERR(ctrl)) {
                ret = PTR_ERR(ctrl);
                goto out_unlock;
        }

        if (strcmp(ctrl->subnqn, opts->subsysnqn)) {
                dev_warn(ctrl->device,
                        "controller returned incorrect NQN: \"%s\".\n",
                        ctrl->subnqn);
                up_read(&nvmf_transports_rwsem);
                ctrl->ops->delete_ctrl(ctrl);
                return ERR_PTR(-EINVAL);
        }

        up_read(&nvmf_transports_rwsem);
        return ctrl;

out_unlock:
        up_read(&nvmf_transports_rwsem);
out_free_opts:
        nvmf_free_options(opts);
        return ERR_PTR(ret);
}

static struct class *nvmf_class;
static struct device *nvmf_device;
static DEFINE_MUTEX(nvmf_dev_mutex);

static ssize_t nvmf_dev_write(struct file *file, const char __user *ubuf,
                size_t count, loff_t *pos)
{
        struct seq_file *seq_file = file->private_data;
        struct nvme_ctrl *ctrl;
        const char *buf;
        int ret = 0;

        if (count > PAGE_SIZE)
                return -ENOMEM;

        buf = memdup_user_nul(ubuf, count);
        if (IS_ERR(buf))
                return PTR_ERR(buf);

        mutex_lock(&nvmf_dev_mutex);
        if (seq_file->private) {
                ret = -EINVAL;
                goto out_unlock;
        }

        ctrl = nvmf_create_ctrl(nvmf_device, buf, count);
        if (IS_ERR(ctrl)) {
                ret = PTR_ERR(ctrl);
                goto out_unlock;
        }

        seq_file->private = ctrl;

out_unlock:
        mutex_unlock(&nvmf_dev_mutex);
        kfree(buf);
        return ret ? ret : count;
}

static int nvmf_dev_show(struct seq_file *seq_file, void *private)
{
        struct nvme_ctrl *ctrl;
        int ret = 0;

        mutex_lock(&nvmf_dev_mutex);
        ctrl = seq_file->private;
        if (!ctrl) {
                ret = -EINVAL;
                goto out_unlock;
        }

        seq_printf(seq_file, "instance=%d,cntlid=%d\n",
                        ctrl->instance, ctrl->cntlid);

out_unlock:
        mutex_unlock(&nvmf_dev_mutex);
        return ret;
}

static int nvmf_dev_open(struct inode *inode, struct file *file)
{
        /*
         * The miscdevice code initializes file->private_data, but doesn't
         * make use of it later.
         */
        file->private_data = NULL;
        return single_open(file, nvmf_dev_show, NULL);
}

static int nvmf_dev_release(struct inode *inode, struct file *file)
{
        struct seq_file *seq_file = file->private_data;
        struct nvme_ctrl *ctrl = seq_file->private;

        if (ctrl)
                nvme_put_ctrl(ctrl);
        return single_release(inode, file);
}

static const struct file_operations nvmf_dev_fops = {
        .owner          = THIS_MODULE,
        .write          = nvmf_dev_write,
        .read           = seq_read,
        .open           = nvmf_dev_open,
        .release        = nvmf_dev_release,
};

static struct miscdevice nvmf_misc = {
        .minor          = MISC_DYNAMIC_MINOR,
        .name           = "nvme-fabrics",
        .fops           = &nvmf_dev_fops,
};

static int __init nvmf_init(void)
{
        int ret;

        nvmf_default_host = nvmf_host_default();
        if (!nvmf_default_host)
                return -ENOMEM;

        nvmf_class = class_create(THIS_MODULE, "nvme-fabrics");
        if (IS_ERR(nvmf_class)) {
                pr_err("couldn't register class nvme-fabrics\n");
                ret = PTR_ERR(nvmf_class);
                goto out_free_host;
        }

        nvmf_device =
                device_create(nvmf_class, NULL, MKDEV(0, 0), NULL, "ctl");
        if (IS_ERR(nvmf_device)) {
                pr_err("couldn't create nvme-fabris device!\n");
                ret = PTR_ERR(nvmf_device);
                goto out_destroy_class;
        }

        ret = misc_register(&nvmf_misc);
        if (ret) {
                pr_err("couldn't register misc device: %d\n", ret);
                goto out_destroy_device;
        }

        return 0;

out_destroy_device:
        device_destroy(nvmf_class, MKDEV(0, 0));
out_destroy_class:
        class_destroy(nvmf_class);
out_free_host:
        nvmf_host_put(nvmf_default_host);
        return ret;
}

static void __exit nvmf_exit(void)
{
        misc_deregister(&nvmf_misc);
        device_destroy(nvmf_class, MKDEV(0, 0));
        class_destroy(nvmf_class);
        nvmf_host_put(nvmf_default_host);

        BUILD_BUG_ON(sizeof(struct nvmf_connect_command) != 64);
        BUILD_BUG_ON(sizeof(struct nvmf_property_get_command) != 64);
        BUILD_BUG_ON(sizeof(struct nvmf_property_set_command) != 64);
        BUILD_BUG_ON(sizeof(struct nvmf_connect_data) != 1024);
}

MODULE_LICENSE("GPL v2");

module_init(nvmf_init);
module_exit(nvmf_exit);