Linux 5.6-rc7

[linux.git] / drivers / nvme / host / fc.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2016 Avago Technologies.  All rights reserved.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/parser.h>
#include <uapi/scsi/fc/fc_fs.h>
#include <uapi/scsi/fc/fc_els.h>
#include <linux/delay.h>
#include <linux/overflow.h>

#include "nvme.h"
#include "fabrics.h"
#include <linux/nvme-fc-driver.h>
#include <linux/nvme-fc.h>
#include <scsi/scsi_transport_fc.h>

/* *************************** Data Structures/Defines ****************** */


enum nvme_fc_queue_flags {
        NVME_FC_Q_CONNECTED = 0,
        NVME_FC_Q_LIVE,
};

#define NVME_FC_DEFAULT_DEV_LOSS_TMO    60      /* seconds */

struct nvme_fc_queue {
        struct nvme_fc_ctrl     *ctrl;
        struct device           *dev;
        struct blk_mq_hw_ctx    *hctx;
        void                    *lldd_handle;
        size_t                  cmnd_capsule_len;
        u32                     qnum;
        u32                     rqcnt;
        u32                     seqno;

        u64                     connection_id;
        atomic_t                csn;

        unsigned long           flags;
} __aligned(sizeof(u64));       /* alignment for other things alloc'd with */

enum nvme_fcop_flags {
        FCOP_FLAGS_TERMIO       = (1 << 0),
        FCOP_FLAGS_AEN          = (1 << 1),
};

struct nvmefc_ls_req_op {
        struct nvmefc_ls_req    ls_req;

        struct nvme_fc_rport    *rport;
        struct nvme_fc_queue    *queue;
        struct request          *rq;
        u32                     flags;

        int                     ls_error;
        struct completion       ls_done;
        struct list_head        lsreq_list;     /* rport->ls_req_list */
        bool                    req_queued;
};

enum nvme_fcpop_state {
        FCPOP_STATE_UNINIT      = 0,
        FCPOP_STATE_IDLE        = 1,
        FCPOP_STATE_ACTIVE      = 2,
        FCPOP_STATE_ABORTED     = 3,
        FCPOP_STATE_COMPLETE    = 4,
};

struct nvme_fc_fcp_op {
        struct nvme_request     nreq;           /*
                                                 * nvme/host/core.c
                                                 * requires this to be
                                                 * the 1st element in the
                                                 * private structure
                                                 * associated with the
                                                 * request.
                                                 */
        struct nvmefc_fcp_req   fcp_req;

        struct nvme_fc_ctrl     *ctrl;
        struct nvme_fc_queue    *queue;
        struct request          *rq;

        atomic_t                state;
        u32                     flags;
        u32                     rqno;
        u32                     nents;

        struct nvme_fc_cmd_iu   cmd_iu;
        struct nvme_fc_ersp_iu  rsp_iu;
};

struct nvme_fcp_op_w_sgl {
        struct nvme_fc_fcp_op   op;
        struct scatterlist      sgl[NVME_INLINE_SG_CNT];
        uint8_t                 priv[0];
};

struct nvme_fc_lport {
        struct nvme_fc_local_port       localport;

        struct ida                      endp_cnt;
        struct list_head                port_list;      /* nvme_fc_port_list */
        struct list_head                endp_list;
        struct device                   *dev;   /* physical device for dma */
        struct nvme_fc_port_template    *ops;
        struct kref                     ref;
        atomic_t                        act_rport_cnt;
} __aligned(sizeof(u64));       /* alignment for other things alloc'd with */

struct nvme_fc_rport {
        struct nvme_fc_remote_port      remoteport;

        struct list_head                endp_list; /* for lport->endp_list */
        struct list_head                ctrl_list;
        struct list_head                ls_req_list;
        struct list_head                disc_list;
        struct device                   *dev;   /* physical device for dma */
        struct nvme_fc_lport            *lport;
        spinlock_t                      lock;
        struct kref                     ref;
        atomic_t                        act_ctrl_cnt;
        unsigned long                   dev_loss_end;
} __aligned(sizeof(u64));       /* alignment for other things alloc'd with */

enum nvme_fcctrl_flags {
        FCCTRL_TERMIO           = (1 << 0),
};

struct nvme_fc_ctrl {
        spinlock_t              lock;
        struct nvme_fc_queue    *queues;
        struct device           *dev;
        struct nvme_fc_lport    *lport;
        struct nvme_fc_rport    *rport;
        u32                     cnum;

        bool                    ioq_live;
        bool                    assoc_active;
        atomic_t                err_work_active;
        u64                     association_id;

        struct list_head        ctrl_list;      /* rport->ctrl_list */

        struct blk_mq_tag_set   admin_tag_set;
        struct blk_mq_tag_set   tag_set;

        struct delayed_work     connect_work;
        struct work_struct      err_work;

        struct kref             ref;
        u32                     flags;
        u32                     iocnt;
        wait_queue_head_t       ioabort_wait;

        struct nvme_fc_fcp_op   aen_ops[NVME_NR_AEN_COMMANDS];

        struct nvme_ctrl        ctrl;
};

static inline struct nvme_fc_ctrl *
to_fc_ctrl(struct nvme_ctrl *ctrl)
{
        return container_of(ctrl, struct nvme_fc_ctrl, ctrl);
}

static inline struct nvme_fc_lport *
localport_to_lport(struct nvme_fc_local_port *portptr)
{
        return container_of(portptr, struct nvme_fc_lport, localport);
}

static inline struct nvme_fc_rport *
remoteport_to_rport(struct nvme_fc_remote_port *portptr)
{
        return container_of(portptr, struct nvme_fc_rport, remoteport);
}

static inline struct nvmefc_ls_req_op *
ls_req_to_lsop(struct nvmefc_ls_req *lsreq)
{
        return container_of(lsreq, struct nvmefc_ls_req_op, ls_req);
}

static inline struct nvme_fc_fcp_op *
fcp_req_to_fcp_op(struct nvmefc_fcp_req *fcpreq)
{
        return container_of(fcpreq, struct nvme_fc_fcp_op, fcp_req);
}



/* *************************** Globals **************************** */


static DEFINE_SPINLOCK(nvme_fc_lock);

static LIST_HEAD(nvme_fc_lport_list);
static DEFINE_IDA(nvme_fc_local_port_cnt);
static DEFINE_IDA(nvme_fc_ctrl_cnt);

static struct workqueue_struct *nvme_fc_wq;

static bool nvme_fc_waiting_to_unload;
static DECLARE_COMPLETION(nvme_fc_unload_proceed);

/*
 * These items are short-term. They will eventually be moved into
 * a generic FC class. See comments in module init.
 */
static struct device *fc_udev_device;


/* *********************** FC-NVME Port Management ************************ */

static void __nvme_fc_delete_hw_queue(struct nvme_fc_ctrl *,
                        struct nvme_fc_queue *, unsigned int);

static void
nvme_fc_free_lport(struct kref *ref)
{
        struct nvme_fc_lport *lport =
                container_of(ref, struct nvme_fc_lport, ref);
        unsigned long flags;

        WARN_ON(lport->localport.port_state != FC_OBJSTATE_DELETED);
        WARN_ON(!list_empty(&lport->endp_list));

        /* remove from transport list */
        spin_lock_irqsave(&nvme_fc_lock, flags);
        list_del(&lport->port_list);
        if (nvme_fc_waiting_to_unload && list_empty(&nvme_fc_lport_list))
                complete(&nvme_fc_unload_proceed);
        spin_unlock_irqrestore(&nvme_fc_lock, flags);

        ida_simple_remove(&nvme_fc_local_port_cnt, lport->localport.port_num);
        ida_destroy(&lport->endp_cnt);

        put_device(lport->dev);

        kfree(lport);
}

static void
nvme_fc_lport_put(struct nvme_fc_lport *lport)
{
        kref_put(&lport->ref, nvme_fc_free_lport);
}

static int
nvme_fc_lport_get(struct nvme_fc_lport *lport)
{
        return kref_get_unless_zero(&lport->ref);
}


static struct nvme_fc_lport *
nvme_fc_attach_to_unreg_lport(struct nvme_fc_port_info *pinfo,
                        struct nvme_fc_port_template *ops,
                        struct device *dev)
{
        struct nvme_fc_lport *lport;
        unsigned long flags;

        spin_lock_irqsave(&nvme_fc_lock, flags);

        list_for_each_entry(lport, &nvme_fc_lport_list, port_list) {
                if (lport->localport.node_name != pinfo->node_name ||
                    lport->localport.port_name != pinfo->port_name)
                        continue;

                if (lport->dev != dev) {
                        lport = ERR_PTR(-EXDEV);
                        goto out_done;
                }

                if (lport->localport.port_state != FC_OBJSTATE_DELETED) {
                        lport = ERR_PTR(-EEXIST);
                        goto out_done;
                }

                if (!nvme_fc_lport_get(lport)) {
                        /*
                         * fails if ref cnt already 0. If so,
                         * act as if lport already deleted
                         */
                        lport = NULL;
                        goto out_done;
                }

                /* resume the lport */

                lport->ops = ops;
                lport->localport.port_role = pinfo->port_role;
                lport->localport.port_id = pinfo->port_id;
                lport->localport.port_state = FC_OBJSTATE_ONLINE;

                spin_unlock_irqrestore(&nvme_fc_lock, flags);

                return lport;
        }

        lport = NULL;

out_done:
        spin_unlock_irqrestore(&nvme_fc_lock, flags);

        return lport;
}

/**
 * nvme_fc_register_localport - transport entry point called by an
 *                              LLDD to register the existence of a NVME
 *                              host FC port.
 * @pinfo:     pointer to information about the port to be registered
 * @template:  LLDD entrypoints and operational parameters for the port
 * @dev:       physical hardware device node port corresponds to. Will be
 *             used for DMA mappings
 * @portptr:   pointer to a local port pointer. Upon success, the routine
 *             will allocate a nvme_fc_local_port structure and place its
 *             address in the local port pointer. Upon failure, local port
 *             pointer will be set to 0.
 *
 * Returns:
 * a completion status. Must be 0 upon success; a negative errno
 * (ex: -ENXIO) upon failure.
 */
int
nvme_fc_register_localport(struct nvme_fc_port_info *pinfo,
                        struct nvme_fc_port_template *template,
                        struct device *dev,
                        struct nvme_fc_local_port **portptr)
{
        struct nvme_fc_lport *newrec;
        unsigned long flags;
        int ret, idx;

        if (!template->localport_delete || !template->remoteport_delete ||
            !template->ls_req || !template->fcp_io ||
            !template->ls_abort || !template->fcp_abort ||
            !template->max_hw_queues || !template->max_sgl_segments ||
            !template->max_dif_sgl_segments || !template->dma_boundary ||
            !template->module) {
                ret = -EINVAL;
                goto out_reghost_failed;
        }

        /*
         * look to see if there is already a localport that had been
         * deregistered and in the process of waiting for all the
         * references to fully be removed.  If the references haven't
         * expired, we can simply re-enable the localport. Remoteports
         * and controller reconnections should resume naturally.
         */
        newrec = nvme_fc_attach_to_unreg_lport(pinfo, template, dev);

        /* found an lport, but something about its state is bad */
        if (IS_ERR(newrec)) {
                ret = PTR_ERR(newrec);
                goto out_reghost_failed;

        /* found existing lport, which was resumed */
        } else if (newrec) {
                *portptr = &newrec->localport;
                return 0;
        }

        /* nothing found - allocate a new localport struct */

        newrec = kmalloc((sizeof(*newrec) + template->local_priv_sz),
                         GFP_KERNEL);
        if (!newrec) {
                ret = -ENOMEM;
                goto out_reghost_failed;
        }

        idx = ida_simple_get(&nvme_fc_local_port_cnt, 0, 0, GFP_KERNEL);
        if (idx < 0) {
                ret = -ENOSPC;
                goto out_fail_kfree;
        }

        if (!get_device(dev) && dev) {
                ret = -ENODEV;
                goto out_ida_put;
        }

        INIT_LIST_HEAD(&newrec->port_list);
        INIT_LIST_HEAD(&newrec->endp_list);
        kref_init(&newrec->ref);
        atomic_set(&newrec->act_rport_cnt, 0);
        newrec->ops = template;
        newrec->dev = dev;
        ida_init(&newrec->endp_cnt);
        newrec->localport.private = &newrec[1];
        newrec->localport.node_name = pinfo->node_name;
        newrec->localport.port_name = pinfo->port_name;
        newrec->localport.port_role = pinfo->port_role;
        newrec->localport.port_id = pinfo->port_id;
        newrec->localport.port_state = FC_OBJSTATE_ONLINE;
        newrec->localport.port_num = idx;

        spin_lock_irqsave(&nvme_fc_lock, flags);
        list_add_tail(&newrec->port_list, &nvme_fc_lport_list);
        spin_unlock_irqrestore(&nvme_fc_lock, flags);

        if (dev)
                dma_set_seg_boundary(dev, template->dma_boundary);

        *portptr = &newrec->localport;
        return 0;

out_ida_put:
        ida_simple_remove(&nvme_fc_local_port_cnt, idx);
out_fail_kfree:
        kfree(newrec);
out_reghost_failed:
        *portptr = NULL;

        return ret;
}
EXPORT_SYMBOL_GPL(nvme_fc_register_localport);

/**
 * nvme_fc_unregister_localport - transport entry point called by an
 *                              LLDD to deregister/remove a previously
 *                              registered a NVME host FC port.
 * @portptr: pointer to the (registered) local port that is to be deregistered.
 *
 * Returns:
 * a completion status. Must be 0 upon success; a negative errno
 * (ex: -ENXIO) upon failure.
 */
int
nvme_fc_unregister_localport(struct nvme_fc_local_port *portptr)
{
        struct nvme_fc_lport *lport = localport_to_lport(portptr);
        unsigned long flags;

        if (!portptr)
                return -EINVAL;

        spin_lock_irqsave(&nvme_fc_lock, flags);

        if (portptr->port_state != FC_OBJSTATE_ONLINE) {
                spin_unlock_irqrestore(&nvme_fc_lock, flags);
                return -EINVAL;
        }
        portptr->port_state = FC_OBJSTATE_DELETED;

        spin_unlock_irqrestore(&nvme_fc_lock, flags);

        if (atomic_read(&lport->act_rport_cnt) == 0)
                lport->ops->localport_delete(&lport->localport);

        nvme_fc_lport_put(lport);

        return 0;
}
EXPORT_SYMBOL_GPL(nvme_fc_unregister_localport);

/*
 * TRADDR strings, per FC-NVME are fixed format:
 *   "nn-0x<16hexdigits>:pn-0x<16hexdigits>" - 43 characters
 * udev event will only differ by prefix of what field is
 * being specified:
 *    "NVMEFC_HOST_TRADDR=" or "NVMEFC_TRADDR=" - 19 max characters
 *  19 + 43 + null_fudge = 64 characters
 */
#define FCNVME_TRADDR_LENGTH            64

static void
nvme_fc_signal_discovery_scan(struct nvme_fc_lport *lport,
                struct nvme_fc_rport *rport)
{
        char hostaddr[FCNVME_TRADDR_LENGTH];    /* NVMEFC_HOST_TRADDR=...*/
        char tgtaddr[FCNVME_TRADDR_LENGTH];     /* NVMEFC_TRADDR=...*/
        char *envp[4] = { "FC_EVENT=nvmediscovery", hostaddr, tgtaddr, NULL };

        if (!(rport->remoteport.port_role & FC_PORT_ROLE_NVME_DISCOVERY))
                return;

        snprintf(hostaddr, sizeof(hostaddr),
                "NVMEFC_HOST_TRADDR=nn-0x%016llx:pn-0x%016llx",
                lport->localport.node_name, lport->localport.port_name);
        snprintf(tgtaddr, sizeof(tgtaddr),
                "NVMEFC_TRADDR=nn-0x%016llx:pn-0x%016llx",
                rport->remoteport.node_name, rport->remoteport.port_name);
        kobject_uevent_env(&fc_udev_device->kobj, KOBJ_CHANGE, envp);
}

static void
nvme_fc_free_rport(struct kref *ref)
{
        struct nvme_fc_rport *rport =
                container_of(ref, struct nvme_fc_rport, ref);
        struct nvme_fc_lport *lport =
                        localport_to_lport(rport->remoteport.localport);
        unsigned long flags;

        WARN_ON(rport->remoteport.port_state != FC_OBJSTATE_DELETED);
        WARN_ON(!list_empty(&rport->ctrl_list));

        /* remove from lport list */
        spin_lock_irqsave(&nvme_fc_lock, flags);
        list_del(&rport->endp_list);
        spin_unlock_irqrestore(&nvme_fc_lock, flags);

        WARN_ON(!list_empty(&rport->disc_list));
        ida_simple_remove(&lport->endp_cnt, rport->remoteport.port_num);

        kfree(rport);

        nvme_fc_lport_put(lport);
}

static void
nvme_fc_rport_put(struct nvme_fc_rport *rport)
{
        kref_put(&rport->ref, nvme_fc_free_rport);
}

static int
nvme_fc_rport_get(struct nvme_fc_rport *rport)
{
        return kref_get_unless_zero(&rport->ref);
}

static void
nvme_fc_resume_controller(struct nvme_fc_ctrl *ctrl)
{
        switch (ctrl->ctrl.state) {
        case NVME_CTRL_NEW:
        case NVME_CTRL_CONNECTING:
                /*
                 * As all reconnects were suppressed, schedule a
                 * connect.
                 */
                dev_info(ctrl->ctrl.device,
                        "NVME-FC{%d}: connectivity re-established. "
                        "Attempting reconnect\n", ctrl->cnum);

                queue_delayed_work(nvme_wq, &ctrl->connect_work, 0);
                break;

        case NVME_CTRL_RESETTING:
                /*
                 * Controller is already in the process of terminating the
                 * association. No need to do anything further. The reconnect
                 * step will naturally occur after the reset completes.
                 */
                break;

        default:
                /* no action to take - let it delete */
                break;
        }
}

static struct nvme_fc_rport *
nvme_fc_attach_to_suspended_rport(struct nvme_fc_lport *lport,
                                struct nvme_fc_port_info *pinfo)
{
        struct nvme_fc_rport *rport;
        struct nvme_fc_ctrl *ctrl;
        unsigned long flags;

        spin_lock_irqsave(&nvme_fc_lock, flags);

        list_for_each_entry(rport, &lport->endp_list, endp_list) {
                if (rport->remoteport.node_name != pinfo->node_name ||
                    rport->remoteport.port_name != pinfo->port_name)
                        continue;

                if (!nvme_fc_rport_get(rport)) {
                        rport = ERR_PTR(-ENOLCK);
                        goto out_done;
                }

                spin_unlock_irqrestore(&nvme_fc_lock, flags);

                spin_lock_irqsave(&rport->lock, flags);

                /* has it been unregistered */
                if (rport->remoteport.port_state != FC_OBJSTATE_DELETED) {
                        /* means lldd called us twice */
                        spin_unlock_irqrestore(&rport->lock, flags);
                        nvme_fc_rport_put(rport);
                        return ERR_PTR(-ESTALE);
                }

                rport->remoteport.port_role = pinfo->port_role;
                rport->remoteport.port_id = pinfo->port_id;
                rport->remoteport.port_state = FC_OBJSTATE_ONLINE;
                rport->dev_loss_end = 0;

                /*
                 * kick off a reconnect attempt on all associations to the
                 * remote port. A successful reconnects will resume i/o.
                 */
                list_for_each_entry(ctrl, &rport->ctrl_list, ctrl_list)
                        nvme_fc_resume_controller(ctrl);

                spin_unlock_irqrestore(&rport->lock, flags);

                return rport;
        }

        rport = NULL;

out_done:
        spin_unlock_irqrestore(&nvme_fc_lock, flags);

        return rport;
}

static inline void
__nvme_fc_set_dev_loss_tmo(struct nvme_fc_rport *rport,
                        struct nvme_fc_port_info *pinfo)
{
        if (pinfo->dev_loss_tmo)
                rport->remoteport.dev_loss_tmo = pinfo->dev_loss_tmo;
        else
                rport->remoteport.dev_loss_tmo = NVME_FC_DEFAULT_DEV_LOSS_TMO;
}

/**
 * nvme_fc_register_remoteport - transport entry point called by an
 *                              LLDD to register the existence of a NVME
 *                              subsystem FC port on its fabric.
 * @localport: pointer to the (registered) local port that the remote
 *             subsystem port is connected to.
 * @pinfo:     pointer to information about the port to be registered
 * @portptr:   pointer to a remote port pointer. Upon success, the routine
 *             will allocate a nvme_fc_remote_port structure and place its
 *             address in the remote port pointer. Upon failure, remote port
 *             pointer will be set to 0.
 *
 * Returns:
 * a completion status. Must be 0 upon success; a negative errno
 * (ex: -ENXIO) upon failure.
 */
int
nvme_fc_register_remoteport(struct nvme_fc_local_port *localport,
                                struct nvme_fc_port_info *pinfo,
                                struct nvme_fc_remote_port **portptr)
{
        struct nvme_fc_lport *lport = localport_to_lport(localport);
        struct nvme_fc_rport *newrec;
        unsigned long flags;
        int ret, idx;

        if (!nvme_fc_lport_get(lport)) {
                ret = -ESHUTDOWN;
                goto out_reghost_failed;
        }

        /*
         * look to see if there is already a remoteport that is waiting
         * for a reconnect (within dev_loss_tmo) with the same WWN's.
         * If so, transition to it and reconnect.
         */
        newrec = nvme_fc_attach_to_suspended_rport(lport, pinfo);

        /* found an rport, but something about its state is bad */
        if (IS_ERR(newrec)) {
                ret = PTR_ERR(newrec);
                goto out_lport_put;

        /* found existing rport, which was resumed */
        } else if (newrec) {
                nvme_fc_lport_put(lport);
                __nvme_fc_set_dev_loss_tmo(newrec, pinfo);
                nvme_fc_signal_discovery_scan(lport, newrec);
                *portptr = &newrec->remoteport;
                return 0;
        }

        /* nothing found - allocate a new remoteport struct */

        newrec = kmalloc((sizeof(*newrec) + lport->ops->remote_priv_sz),
                         GFP_KERNEL);
        if (!newrec) {
                ret = -ENOMEM;
                goto out_lport_put;
        }

        idx = ida_simple_get(&lport->endp_cnt, 0, 0, GFP_KERNEL);
        if (idx < 0) {
                ret = -ENOSPC;
                goto out_kfree_rport;
        }

        INIT_LIST_HEAD(&newrec->endp_list);
        INIT_LIST_HEAD(&newrec->ctrl_list);
        INIT_LIST_HEAD(&newrec->ls_req_list);
        INIT_LIST_HEAD(&newrec->disc_list);
        kref_init(&newrec->ref);
        atomic_set(&newrec->act_ctrl_cnt, 0);
        spin_lock_init(&newrec->lock);
        newrec->remoteport.localport = &lport->localport;
        newrec->dev = lport->dev;
        newrec->lport = lport;
        newrec->remoteport.private = &newrec[1];
        newrec->remoteport.port_role = pinfo->port_role;
        newrec->remoteport.node_name = pinfo->node_name;
        newrec->remoteport.port_name = pinfo->port_name;
        newrec->remoteport.port_id = pinfo->port_id;
        newrec->remoteport.port_state = FC_OBJSTATE_ONLINE;
        newrec->remoteport.port_num = idx;
        __nvme_fc_set_dev_loss_tmo(newrec, pinfo);

        spin_lock_irqsave(&nvme_fc_lock, flags);
        list_add_tail(&newrec->endp_list, &lport->endp_list);
        spin_unlock_irqrestore(&nvme_fc_lock, flags);

        nvme_fc_signal_discovery_scan(lport, newrec);

        *portptr = &newrec->remoteport;
        return 0;

out_kfree_rport:
        kfree(newrec);
out_lport_put:
        nvme_fc_lport_put(lport);
out_reghost_failed:
        *portptr = NULL;
        return ret;
}
EXPORT_SYMBOL_GPL(nvme_fc_register_remoteport);

static int
nvme_fc_abort_lsops(struct nvme_fc_rport *rport)
{
        struct nvmefc_ls_req_op *lsop;
        unsigned long flags;

restart:
        spin_lock_irqsave(&rport->lock, flags);

        list_for_each_entry(lsop, &rport->ls_req_list, lsreq_list) {
                if (!(lsop->flags & FCOP_FLAGS_TERMIO)) {
                        lsop->flags |= FCOP_FLAGS_TERMIO;
                        spin_unlock_irqrestore(&rport->lock, flags);
                        rport->lport->ops->ls_abort(&rport->lport->localport,
                                                &rport->remoteport,
                                                &lsop->ls_req);
                        goto restart;
                }
        }
        spin_unlock_irqrestore(&rport->lock, flags);

        return 0;
}

static void
nvme_fc_ctrl_connectivity_loss(struct nvme_fc_ctrl *ctrl)
{
        dev_info(ctrl->ctrl.device,
                "NVME-FC{%d}: controller connectivity lost. Awaiting "
                "Reconnect", ctrl->cnum);

        switch (ctrl->ctrl.state) {
        case NVME_CTRL_NEW:
        case NVME_CTRL_LIVE:
                /*
                 * Schedule a controller reset. The reset will terminate the
                 * association and schedule the reconnect timer.  Reconnects
                 * will be attempted until either the ctlr_loss_tmo
                 * (max_retries * connect_delay) expires or the remoteport's
                 * dev_loss_tmo expires.
                 */
                if (nvme_reset_ctrl(&ctrl->ctrl)) {
                        dev_warn(ctrl->ctrl.device,
                                "NVME-FC{%d}: Couldn't schedule reset.\n",
                                ctrl->cnum);
                        nvme_delete_ctrl(&ctrl->ctrl);
                }
                break;

        case NVME_CTRL_CONNECTING:
                /*
                 * The association has already been terminated and the
                 * controller is attempting reconnects.  No need to do anything
                 * futher.  Reconnects will be attempted until either the
                 * ctlr_loss_tmo (max_retries * connect_delay) expires or the
                 * remoteport's dev_loss_tmo expires.
                 */
                break;

        case NVME_CTRL_RESETTING:
                /*
                 * Controller is already in the process of terminating the
                 * association.  No need to do anything further. The reconnect
                 * step will kick in naturally after the association is
                 * terminated.
                 */
                break;

        case NVME_CTRL_DELETING:
        default:
                /* no action to take - let it delete */
                break;
        }
}

/**
 * nvme_fc_unregister_remoteport - transport entry point called by an
 *                              LLDD to deregister/remove a previously
 *                              registered a NVME subsystem FC port.
 * @portptr: pointer to the (registered) remote port that is to be
 *           deregistered.
 *
 * Returns:
 * a completion status. Must be 0 upon success; a negative errno
 * (ex: -ENXIO) upon failure.
 */
int
nvme_fc_unregister_remoteport(struct nvme_fc_remote_port *portptr)
{
        struct nvme_fc_rport *rport = remoteport_to_rport(portptr);
        struct nvme_fc_ctrl *ctrl;
        unsigned long flags;

        if (!portptr)
                return -EINVAL;

        spin_lock_irqsave(&rport->lock, flags);

        if (portptr->port_state != FC_OBJSTATE_ONLINE) {
                spin_unlock_irqrestore(&rport->lock, flags);
                return -EINVAL;
        }
        portptr->port_state = FC_OBJSTATE_DELETED;

        rport->dev_loss_end = jiffies + (portptr->dev_loss_tmo * HZ);

        list_for_each_entry(ctrl, &rport->ctrl_list, ctrl_list) {
                /* if dev_loss_tmo==0, dev loss is immediate */
                if (!portptr->dev_loss_tmo) {
                        dev_warn(ctrl->ctrl.device,
                                "NVME-FC{%d}: controller connectivity lost.\n",
                                ctrl->cnum);
                        nvme_delete_ctrl(&ctrl->ctrl);
                } else
                        nvme_fc_ctrl_connectivity_loss(ctrl);
        }

        spin_unlock_irqrestore(&rport->lock, flags);

        nvme_fc_abort_lsops(rport);

        if (atomic_read(&rport->act_ctrl_cnt) == 0)
                rport->lport->ops->remoteport_delete(portptr);

        /*
         * release the reference, which will allow, if all controllers
         * go away, which should only occur after dev_loss_tmo occurs,
         * for the rport to be torn down.
         */
        nvme_fc_rport_put(rport);

        return 0;
}
EXPORT_SYMBOL_GPL(nvme_fc_unregister_remoteport);

/**
 * nvme_fc_rescan_remoteport - transport entry point called by an
 *                              LLDD to request a nvme device rescan.
 * @remoteport: pointer to the (registered) remote port that is to be
 *              rescanned.
 *
 * Returns: N/A
 */
void
nvme_fc_rescan_remoteport(struct nvme_fc_remote_port *remoteport)
{
        struct nvme_fc_rport *rport = remoteport_to_rport(remoteport);

        nvme_fc_signal_discovery_scan(rport->lport, rport);
}
EXPORT_SYMBOL_GPL(nvme_fc_rescan_remoteport);

int
nvme_fc_set_remoteport_devloss(struct nvme_fc_remote_port *portptr,
                        u32 dev_loss_tmo)
{
        struct nvme_fc_rport *rport = remoteport_to_rport(portptr);
        unsigned long flags;

        spin_lock_irqsave(&rport->lock, flags);

        if (portptr->port_state != FC_OBJSTATE_ONLINE) {
                spin_unlock_irqrestore(&rport->lock, flags);
                return -EINVAL;
        }

        /* a dev_loss_tmo of 0 (immediate) is allowed to be set */
        rport->remoteport.dev_loss_tmo = dev_loss_tmo;

        spin_unlock_irqrestore(&rport->lock, flags);

        return 0;
}
EXPORT_SYMBOL_GPL(nvme_fc_set_remoteport_devloss);


/* *********************** FC-NVME DMA Handling **************************** */

/*
 * The fcloop device passes in a NULL device pointer. Real LLD's will
 * pass in a valid device pointer. If NULL is passed to the dma mapping
 * routines, depending on the platform, it may or may not succeed, and
 * may crash.
 *
 * As such:
 * Wrapper all the dma routines and check the dev pointer.
 *
 * If simple mappings (return just a dma address, we'll noop them,
 * returning a dma address of 0.
 *
 * On more complex mappings (dma_map_sg), a pseudo routine fills
 * in the scatter list, setting all dma addresses to 0.
 */

static inline dma_addr_t
fc_dma_map_single(struct device *dev, void *ptr, size_t size,
                enum dma_data_direction dir)
{
        return dev ? dma_map_single(dev, ptr, size, dir) : (dma_addr_t)0L;
}

static inline int
fc_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
        return dev ? dma_mapping_error(dev, dma_addr) : 0;
}

static inline void
fc_dma_unmap_single(struct device *dev, dma_addr_t addr, size_t size,
        enum dma_data_direction dir)
{
        if (dev)
                dma_unmap_single(dev, addr, size, dir);
}

static inline void
fc_dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
                enum dma_data_direction dir)
{
        if (dev)
                dma_sync_single_for_cpu(dev, addr, size, dir);
}

static inline void
fc_dma_sync_single_for_device(struct device *dev, dma_addr_t addr, size_t size,
                enum dma_data_direction dir)
{
        if (dev)
                dma_sync_single_for_device(dev, addr, size, dir);
}

/* pseudo dma_map_sg call */
static int
fc_map_sg(struct scatterlist *sg, int nents)
{
        struct scatterlist *s;
        int i;

        WARN_ON(nents == 0 || sg[0].length == 0);

        for_each_sg(sg, s, nents, i) {
                s->dma_address = 0L;
#ifdef CONFIG_NEED_SG_DMA_LENGTH
                s->dma_length = s->length;
#endif
        }
        return nents;
}

static inline int
fc_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
                enum dma_data_direction dir)
{
        return dev ? dma_map_sg(dev, sg, nents, dir) : fc_map_sg(sg, nents);
}

static inline void
fc_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
                enum dma_data_direction dir)
{
        if (dev)
                dma_unmap_sg(dev, sg, nents, dir);
}

/* *********************** FC-NVME LS Handling **************************** */

static void nvme_fc_ctrl_put(struct nvme_fc_ctrl *);
static int nvme_fc_ctrl_get(struct nvme_fc_ctrl *);


static void
__nvme_fc_finish_ls_req(struct nvmefc_ls_req_op *lsop)
{
        struct nvme_fc_rport *rport = lsop->rport;
        struct nvmefc_ls_req *lsreq = &lsop->ls_req;
        unsigned long flags;

        spin_lock_irqsave(&rport->lock, flags);

        if (!lsop->req_queued) {
                spin_unlock_irqrestore(&rport->lock, flags);
                return;
        }

        list_del(&lsop->lsreq_list);

        lsop->req_queued = false;

        spin_unlock_irqrestore(&rport->lock, flags);

        fc_dma_unmap_single(rport->dev, lsreq->rqstdma,
                                  (lsreq->rqstlen + lsreq->rsplen),
                                  DMA_BIDIRECTIONAL);

        nvme_fc_rport_put(rport);
}

static int
__nvme_fc_send_ls_req(struct nvme_fc_rport *rport,
                struct nvmefc_ls_req_op *lsop,
                void (*done)(struct nvmefc_ls_req *req, int status))
{
        struct nvmefc_ls_req *lsreq = &lsop->ls_req;
        unsigned long flags;
        int ret = 0;

        if (rport->remoteport.port_state != FC_OBJSTATE_ONLINE)
                return -ECONNREFUSED;

        if (!nvme_fc_rport_get(rport))
                return -ESHUTDOWN;

        lsreq->done = done;
        lsop->rport = rport;
        lsop->req_queued = false;
        INIT_LIST_HEAD(&lsop->lsreq_list);
        init_completion(&lsop->ls_done);

        lsreq->rqstdma = fc_dma_map_single(rport->dev, lsreq->rqstaddr,
                                  lsreq->rqstlen + lsreq->rsplen,
                                  DMA_BIDIRECTIONAL);
        if (fc_dma_mapping_error(rport->dev, lsreq->rqstdma)) {
                ret = -EFAULT;
                goto out_putrport;
        }
        lsreq->rspdma = lsreq->rqstdma + lsreq->rqstlen;

        spin_lock_irqsave(&rport->lock, flags);

        list_add_tail(&lsop->lsreq_list, &rport->ls_req_list);

        lsop->req_queued = true;

        spin_unlock_irqrestore(&rport->lock, flags);

        ret = rport->lport->ops->ls_req(&rport->lport->localport,
                                        &rport->remoteport, lsreq);
        if (ret)
                goto out_unlink;

        return 0;

out_unlink:
        lsop->ls_error = ret;
        spin_lock_irqsave(&rport->lock, flags);
        lsop->req_queued = false;
        list_del(&lsop->lsreq_list);
        spin_unlock_irqrestore(&rport->lock, flags);
        fc_dma_unmap_single(rport->dev, lsreq->rqstdma,
                                  (lsreq->rqstlen + lsreq->rsplen),
                                  DMA_BIDIRECTIONAL);
out_putrport:
        nvme_fc_rport_put(rport);

        return ret;
}

static void
nvme_fc_send_ls_req_done(struct nvmefc_ls_req *lsreq, int status)
{
        struct nvmefc_ls_req_op *lsop = ls_req_to_lsop(lsreq);

        lsop->ls_error = status;
        complete(&lsop->ls_done);
}

static int
nvme_fc_send_ls_req(struct nvme_fc_rport *rport, struct nvmefc_ls_req_op *lsop)
{
        struct nvmefc_ls_req *lsreq = &lsop->ls_req;
        struct fcnvme_ls_rjt *rjt = lsreq->rspaddr;
        int ret;

        ret = __nvme_fc_send_ls_req(rport, lsop, nvme_fc_send_ls_req_done);

        if (!ret) {
                /*
                 * No timeout/not interruptible as we need the struct
                 * to exist until the lldd calls us back. Thus mandate
                 * wait until driver calls back. lldd responsible for
                 * the timeout action
                 */
                wait_for_completion(&lsop->ls_done);

                __nvme_fc_finish_ls_req(lsop);

                ret = lsop->ls_error;
        }

        if (ret)
                return ret;

        /* ACC or RJT payload ? */
        if (rjt->w0.ls_cmd == FCNVME_LS_RJT)
                return -ENXIO;

        return 0;
}

static int
nvme_fc_send_ls_req_async(struct nvme_fc_rport *rport,
                struct nvmefc_ls_req_op *lsop,
                void (*done)(struct nvmefc_ls_req *req, int status))
{
        /* don't wait for completion */

        return __nvme_fc_send_ls_req(rport, lsop, done);
}

/* Validation Error indexes into the string table below */
enum {
        VERR_NO_ERROR           = 0,
        VERR_LSACC              = 1,
        VERR_LSDESC_RQST        = 2,
        VERR_LSDESC_RQST_LEN    = 3,
        VERR_ASSOC_ID           = 4,
        VERR_ASSOC_ID_LEN       = 5,
        VERR_CONN_ID            = 6,
        VERR_CONN_ID_LEN        = 7,
        VERR_CR_ASSOC           = 8,
        VERR_CR_ASSOC_ACC_LEN   = 9,
        VERR_CR_CONN            = 10,
        VERR_CR_CONN_ACC_LEN    = 11,
        VERR_DISCONN            = 12,
        VERR_DISCONN_ACC_LEN    = 13,
};

static char *validation_errors[] = {
        "OK",
        "Not LS_ACC",
        "Not LSDESC_RQST",
        "Bad LSDESC_RQST Length",
        "Not Association ID",
        "Bad Association ID Length",
        "Not Connection ID",
        "Bad Connection ID Length",
        "Not CR_ASSOC Rqst",
        "Bad CR_ASSOC ACC Length",
        "Not CR_CONN Rqst",
        "Bad CR_CONN ACC Length",
        "Not Disconnect Rqst",
        "Bad Disconnect ACC Length",
};

static int
nvme_fc_connect_admin_queue(struct nvme_fc_ctrl *ctrl,
        struct nvme_fc_queue *queue, u16 qsize, u16 ersp_ratio)
{
        struct nvmefc_ls_req_op *lsop;
        struct nvmefc_ls_req *lsreq;
        struct fcnvme_ls_cr_assoc_rqst *assoc_rqst;
        struct fcnvme_ls_cr_assoc_acc *assoc_acc;
        int ret, fcret = 0;

        lsop = kzalloc((sizeof(*lsop) +
                         ctrl->lport->ops->lsrqst_priv_sz +
                         sizeof(*assoc_rqst) + sizeof(*assoc_acc)), GFP_KERNEL);
        if (!lsop) {
                ret = -ENOMEM;
                goto out_no_memory;
        }
        lsreq = &lsop->ls_req;

        lsreq->private = (void *)&lsop[1];
        assoc_rqst = (struct fcnvme_ls_cr_assoc_rqst *)
                        (lsreq->private + ctrl->lport->ops->lsrqst_priv_sz);
        assoc_acc = (struct fcnvme_ls_cr_assoc_acc *)&assoc_rqst[1];

        assoc_rqst->w0.ls_cmd = FCNVME_LS_CREATE_ASSOCIATION;
        assoc_rqst->desc_list_len =
                        cpu_to_be32(sizeof(struct fcnvme_lsdesc_cr_assoc_cmd));

        assoc_rqst->assoc_cmd.desc_tag =
                        cpu_to_be32(FCNVME_LSDESC_CREATE_ASSOC_CMD);
        assoc_rqst->assoc_cmd.desc_len =
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_lsdesc_cr_assoc_cmd));

        assoc_rqst->assoc_cmd.ersp_ratio = cpu_to_be16(ersp_ratio);
        assoc_rqst->assoc_cmd.sqsize = cpu_to_be16(qsize - 1);
        /* Linux supports only Dynamic controllers */
        assoc_rqst->assoc_cmd.cntlid = cpu_to_be16(0xffff);
        uuid_copy(&assoc_rqst->assoc_cmd.hostid, &ctrl->ctrl.opts->host->id);
        strncpy(assoc_rqst->assoc_cmd.hostnqn, ctrl->ctrl.opts->host->nqn,
                min(FCNVME_ASSOC_HOSTNQN_LEN, NVMF_NQN_SIZE));
        strncpy(assoc_rqst->assoc_cmd.subnqn, ctrl->ctrl.opts->subsysnqn,
                min(FCNVME_ASSOC_SUBNQN_LEN, NVMF_NQN_SIZE));

        lsop->queue = queue;
        lsreq->rqstaddr = assoc_rqst;
        lsreq->rqstlen = sizeof(*assoc_rqst);
        lsreq->rspaddr = assoc_acc;
        lsreq->rsplen = sizeof(*assoc_acc);
        lsreq->timeout = NVME_FC_LS_TIMEOUT_SEC;

        ret = nvme_fc_send_ls_req(ctrl->rport, lsop);
        if (ret)
                goto out_free_buffer;

        /* process connect LS completion */

        /* validate the ACC response */
        if (assoc_acc->hdr.w0.ls_cmd != FCNVME_LS_ACC)
                fcret = VERR_LSACC;
        else if (assoc_acc->hdr.desc_list_len !=
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_ls_cr_assoc_acc)))
                fcret = VERR_CR_ASSOC_ACC_LEN;
        else if (assoc_acc->hdr.rqst.desc_tag !=
                        cpu_to_be32(FCNVME_LSDESC_RQST))
                fcret = VERR_LSDESC_RQST;
        else if (assoc_acc->hdr.rqst.desc_len !=
                        fcnvme_lsdesc_len(sizeof(struct fcnvme_lsdesc_rqst)))
                fcret = VERR_LSDESC_RQST_LEN;
        else if (assoc_acc->hdr.rqst.w0.ls_cmd != FCNVME_LS_CREATE_ASSOCIATION)
                fcret = VERR_CR_ASSOC;
        else if (assoc_acc->associd.desc_tag !=
                        cpu_to_be32(FCNVME_LSDESC_ASSOC_ID))
                fcret = VERR_ASSOC_ID;
        else if (assoc_acc->associd.desc_len !=
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_lsdesc_assoc_id)))
                fcret = VERR_ASSOC_ID_LEN;
        else if (assoc_acc->connectid.desc_tag !=
                        cpu_to_be32(FCNVME_LSDESC_CONN_ID))
                fcret = VERR_CONN_ID;
        else if (assoc_acc->connectid.desc_len !=
                        fcnvme_lsdesc_len(sizeof(struct fcnvme_lsdesc_conn_id)))
                fcret = VERR_CONN_ID_LEN;

        if (fcret) {
                ret = -EBADF;
                dev_err(ctrl->dev,
                        "q %d Create Association LS failed: %s\n",
                        queue->qnum, validation_errors[fcret]);
        } else {
                ctrl->association_id =
                        be64_to_cpu(assoc_acc->associd.association_id);
                queue->connection_id =
                        be64_to_cpu(assoc_acc->connectid.connection_id);
                set_bit(NVME_FC_Q_CONNECTED, &queue->flags);
        }

out_free_buffer:
        kfree(lsop);
out_no_memory:
        if (ret)
                dev_err(ctrl->dev,
                        "queue %d connect admin queue failed (%d).\n",
                        queue->qnum, ret);
        return ret;
}

static int
nvme_fc_connect_queue(struct nvme_fc_ctrl *ctrl, struct nvme_fc_queue *queue,
                        u16 qsize, u16 ersp_ratio)
{
        struct nvmefc_ls_req_op *lsop;
        struct nvmefc_ls_req *lsreq;
        struct fcnvme_ls_cr_conn_rqst *conn_rqst;
        struct fcnvme_ls_cr_conn_acc *conn_acc;
        int ret, fcret = 0;

        lsop = kzalloc((sizeof(*lsop) +
                         ctrl->lport->ops->lsrqst_priv_sz +
                         sizeof(*conn_rqst) + sizeof(*conn_acc)), GFP_KERNEL);
        if (!lsop) {
                ret = -ENOMEM;
                goto out_no_memory;
        }
        lsreq = &lsop->ls_req;

        lsreq->private = (void *)&lsop[1];
        conn_rqst = (struct fcnvme_ls_cr_conn_rqst *)
                        (lsreq->private + ctrl->lport->ops->lsrqst_priv_sz);
        conn_acc = (struct fcnvme_ls_cr_conn_acc *)&conn_rqst[1];

        conn_rqst->w0.ls_cmd = FCNVME_LS_CREATE_CONNECTION;
        conn_rqst->desc_list_len = cpu_to_be32(
                                sizeof(struct fcnvme_lsdesc_assoc_id) +
                                sizeof(struct fcnvme_lsdesc_cr_conn_cmd));

        conn_rqst->associd.desc_tag = cpu_to_be32(FCNVME_LSDESC_ASSOC_ID);
        conn_rqst->associd.desc_len =
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_lsdesc_assoc_id));
        conn_rqst->associd.association_id = cpu_to_be64(ctrl->association_id);
        conn_rqst->connect_cmd.desc_tag =
                        cpu_to_be32(FCNVME_LSDESC_CREATE_CONN_CMD);
        conn_rqst->connect_cmd.desc_len =
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_lsdesc_cr_conn_cmd));
        conn_rqst->connect_cmd.ersp_ratio = cpu_to_be16(ersp_ratio);
        conn_rqst->connect_cmd.qid  = cpu_to_be16(queue->qnum);
        conn_rqst->connect_cmd.sqsize = cpu_to_be16(qsize - 1);

        lsop->queue = queue;
        lsreq->rqstaddr = conn_rqst;
        lsreq->rqstlen = sizeof(*conn_rqst);
        lsreq->rspaddr = conn_acc;
        lsreq->rsplen = sizeof(*conn_acc);
        lsreq->timeout = NVME_FC_LS_TIMEOUT_SEC;

        ret = nvme_fc_send_ls_req(ctrl->rport, lsop);
        if (ret)
                goto out_free_buffer;

        /* process connect LS completion */

        /* validate the ACC response */
        if (conn_acc->hdr.w0.ls_cmd != FCNVME_LS_ACC)
                fcret = VERR_LSACC;
        else if (conn_acc->hdr.desc_list_len !=
                        fcnvme_lsdesc_len(sizeof(struct fcnvme_ls_cr_conn_acc)))
                fcret = VERR_CR_CONN_ACC_LEN;
        else if (conn_acc->hdr.rqst.desc_tag != cpu_to_be32(FCNVME_LSDESC_RQST))
                fcret = VERR_LSDESC_RQST;
        else if (conn_acc->hdr.rqst.desc_len !=
                        fcnvme_lsdesc_len(sizeof(struct fcnvme_lsdesc_rqst)))
                fcret = VERR_LSDESC_RQST_LEN;
        else if (conn_acc->hdr.rqst.w0.ls_cmd != FCNVME_LS_CREATE_CONNECTION)
                fcret = VERR_CR_CONN;
        else if (conn_acc->connectid.desc_tag !=
                        cpu_to_be32(FCNVME_LSDESC_CONN_ID))
                fcret = VERR_CONN_ID;
        else if (conn_acc->connectid.desc_len !=
                        fcnvme_lsdesc_len(sizeof(struct fcnvme_lsdesc_conn_id)))
                fcret = VERR_CONN_ID_LEN;

        if (fcret) {
                ret = -EBADF;
                dev_err(ctrl->dev,
                        "q %d Create I/O Connection LS failed: %s\n",
                        queue->qnum, validation_errors[fcret]);
        } else {
                queue->connection_id =
                        be64_to_cpu(conn_acc->connectid.connection_id);
                set_bit(NVME_FC_Q_CONNECTED, &queue->flags);
        }

out_free_buffer:
        kfree(lsop);
out_no_memory:
        if (ret)
                dev_err(ctrl->dev,
                        "queue %d connect I/O queue failed (%d).\n",
                        queue->qnum, ret);
        return ret;
}

static void
nvme_fc_disconnect_assoc_done(struct nvmefc_ls_req *lsreq, int status)
{
        struct nvmefc_ls_req_op *lsop = ls_req_to_lsop(lsreq);

        __nvme_fc_finish_ls_req(lsop);

        /* fc-nvme initiator doesn't care about success or failure of cmd */

        kfree(lsop);
}

/*
 * This routine sends a FC-NVME LS to disconnect (aka terminate)
 * the FC-NVME Association.  Terminating the association also
 * terminates the FC-NVME connections (per queue, both admin and io
 * queues) that are part of the association. E.g. things are torn
 * down, and the related FC-NVME Association ID and Connection IDs
 * become invalid.
 *
 * The behavior of the fc-nvme initiator is such that it's
 * understanding of the association and connections will implicitly
 * be torn down. The action is implicit as it may be due to a loss of
 * connectivity with the fc-nvme target, so you may never get a
 * response even if you tried.  As such, the action of this routine
 * is to asynchronously send the LS, ignore any results of the LS, and
 * continue on with terminating the association. If the fc-nvme target
 * is present and receives the LS, it too can tear down.
 */
static void
nvme_fc_xmt_disconnect_assoc(struct nvme_fc_ctrl *ctrl)
{
        struct fcnvme_ls_disconnect_assoc_rqst *discon_rqst;
        struct fcnvme_ls_disconnect_assoc_acc *discon_acc;
        struct nvmefc_ls_req_op *lsop;
        struct nvmefc_ls_req *lsreq;
        int ret;

        lsop = kzalloc((sizeof(*lsop) +
                         ctrl->lport->ops->lsrqst_priv_sz +
                         sizeof(*discon_rqst) + sizeof(*discon_acc)),
                        GFP_KERNEL);
        if (!lsop)
                /* couldn't sent it... too bad */
                return;

        lsreq = &lsop->ls_req;

        lsreq->private = (void *)&lsop[1];
        discon_rqst = (struct fcnvme_ls_disconnect_assoc_rqst *)
                        (lsreq->private + ctrl->lport->ops->lsrqst_priv_sz);
        discon_acc = (struct fcnvme_ls_disconnect_assoc_acc *)&discon_rqst[1];

        discon_rqst->w0.ls_cmd = FCNVME_LS_DISCONNECT_ASSOC;
        discon_rqst->desc_list_len = cpu_to_be32(
                                sizeof(struct fcnvme_lsdesc_assoc_id) +
                                sizeof(struct fcnvme_lsdesc_disconn_cmd));

        discon_rqst->associd.desc_tag = cpu_to_be32(FCNVME_LSDESC_ASSOC_ID);
        discon_rqst->associd.desc_len =
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_lsdesc_assoc_id));

        discon_rqst->associd.association_id = cpu_to_be64(ctrl->association_id);

        discon_rqst->discon_cmd.desc_tag = cpu_to_be32(
                                                FCNVME_LSDESC_DISCONN_CMD);
        discon_rqst->discon_cmd.desc_len =
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_lsdesc_disconn_cmd));

        lsreq->rqstaddr = discon_rqst;
        lsreq->rqstlen = sizeof(*discon_rqst);
        lsreq->rspaddr = discon_acc;
        lsreq->rsplen = sizeof(*discon_acc);
        lsreq->timeout = NVME_FC_LS_TIMEOUT_SEC;

        ret = nvme_fc_send_ls_req_async(ctrl->rport, lsop,
                                nvme_fc_disconnect_assoc_done);
        if (ret)
                kfree(lsop);
}


/* *********************** NVME Ctrl Routines **************************** */

static void nvme_fc_error_recovery(struct nvme_fc_ctrl *ctrl, char *errmsg);

static void
__nvme_fc_exit_request(struct nvme_fc_ctrl *ctrl,
                struct nvme_fc_fcp_op *op)
{
        fc_dma_unmap_single(ctrl->lport->dev, op->fcp_req.rspdma,
                                sizeof(op->rsp_iu), DMA_FROM_DEVICE);
        fc_dma_unmap_single(ctrl->lport->dev, op->fcp_req.cmddma,
                                sizeof(op->cmd_iu), DMA_TO_DEVICE);

        atomic_set(&op->state, FCPOP_STATE_UNINIT);
}

static void
nvme_fc_exit_request(struct blk_mq_tag_set *set, struct request *rq,
                unsigned int hctx_idx)
{
        struct nvme_fc_fcp_op *op = blk_mq_rq_to_pdu(rq);

        return __nvme_fc_exit_request(set->driver_data, op);
}

static int
__nvme_fc_abort_op(struct nvme_fc_ctrl *ctrl, struct nvme_fc_fcp_op *op)
{
        unsigned long flags;
        int opstate;

        spin_lock_irqsave(&ctrl->lock, flags);
        opstate = atomic_xchg(&op->state, FCPOP_STATE_ABORTED);
        if (opstate != FCPOP_STATE_ACTIVE)
                atomic_set(&op->state, opstate);
        else if (ctrl->flags & FCCTRL_TERMIO)
                ctrl->iocnt++;
        spin_unlock_irqrestore(&ctrl->lock, flags);

        if (opstate != FCPOP_STATE_ACTIVE)
                return -ECANCELED;

        ctrl->lport->ops->fcp_abort(&ctrl->lport->localport,
                                        &ctrl->rport->remoteport,
                                        op->queue->lldd_handle,
                                        &op->fcp_req);

        return 0;
}

static void
nvme_fc_abort_aen_ops(struct nvme_fc_ctrl *ctrl)
{
        struct nvme_fc_fcp_op *aen_op = ctrl->aen_ops;
        int i;

        /* ensure we've initialized the ops once */
        if (!(aen_op->flags & FCOP_FLAGS_AEN))
                return;

        for (i = 0; i < NVME_NR_AEN_COMMANDS; i++, aen_op++)
                __nvme_fc_abort_op(ctrl, aen_op);
}

static inline void
__nvme_fc_fcpop_chk_teardowns(struct nvme_fc_ctrl *ctrl,
                struct nvme_fc_fcp_op *op, int opstate)
{
        unsigned long flags;

        if (opstate == FCPOP_STATE_ABORTED) {
                spin_lock_irqsave(&ctrl->lock, flags);
                if (ctrl->flags & FCCTRL_TERMIO) {
                        if (!--ctrl->iocnt)
                                wake_up(&ctrl->ioabort_wait);
                }
                spin_unlock_irqrestore(&ctrl->lock, flags);
        }
}

static void
nvme_fc_fcpio_done(struct nvmefc_fcp_req *req)
{
        struct nvme_fc_fcp_op *op = fcp_req_to_fcp_op(req);
        struct request *rq = op->rq;
        struct nvmefc_fcp_req *freq = &op->fcp_req;
        struct nvme_fc_ctrl *ctrl = op->ctrl;
        struct nvme_fc_queue *queue = op->queue;
        struct nvme_completion *cqe = &op->rsp_iu.cqe;
        struct nvme_command *sqe = &op->cmd_iu.sqe;
        __le16 status = cpu_to_le16(NVME_SC_SUCCESS << 1);
        union nvme_result result;
        bool terminate_assoc = true;
        int opstate;

        /*
         * WARNING:
         * The current linux implementation of a nvme controller
         * allocates a single tag set for all io queues and sizes
         * the io queues to fully hold all possible tags. Thus, the
         * implementation does not reference or care about the sqhd
         * value as it never needs to use the sqhd/sqtail pointers
         * for submission pacing.
         *
         * This affects the FC-NVME implementation in two ways:
         * 1) As the value doesn't matter, we don't need to waste
         *    cycles extracting it from ERSPs and stamping it in the
         *    cases where the transport fabricates CQEs on successful
         *    completions.
         * 2) The FC-NVME implementation requires that delivery of
         *    ERSP completions are to go back to the nvme layer in order
         *    relative to the rsn, such that the sqhd value will always
         *    be "in order" for the nvme layer. As the nvme layer in
         *    linux doesn't care about sqhd, there's no need to return
         *    them in order.
         *
         * Additionally:
         * As the core nvme layer in linux currently does not look at
         * every field in the cqe - in cases where the FC transport must
         * fabricate a CQE, the following fields will not be set as they
         * are not referenced:
         *      cqe.sqid,  cqe.sqhd,  cqe.command_id
         *
         * Failure or error of an individual i/o, in a transport
         * detected fashion unrelated to the nvme completion status,
         * potentially cause the initiator and target sides to get out
         * of sync on SQ head/tail (aka outstanding io count allowed).
         * Per FC-NVME spec, failure of an individual command requires
         * the connection to be terminated, which in turn requires the
         * association to be terminated.
         */

        opstate = atomic_xchg(&op->state, FCPOP_STATE_COMPLETE);

        fc_dma_sync_single_for_cpu(ctrl->lport->dev, op->fcp_req.rspdma,
                                sizeof(op->rsp_iu), DMA_FROM_DEVICE);

        if (opstate == FCPOP_STATE_ABORTED)
                status = cpu_to_le16(NVME_SC_HOST_PATH_ERROR << 1);
        else if (freq->status) {
                status = cpu_to_le16(NVME_SC_HOST_PATH_ERROR << 1);
                dev_info(ctrl->ctrl.device,
                        "NVME-FC{%d}: io failed due to lldd error %d\n",
                        ctrl->cnum, freq->status);
        }

        /*
         * For the linux implementation, if we have an unsuccesful
         * status, they blk-mq layer can typically be called with the
         * non-zero status and the content of the cqe isn't important.
         */
        if (status)
                goto done;

        /*
         * command completed successfully relative to the wire
         * protocol. However, validate anything received and
         * extract the status and result from the cqe (create it
         * where necessary).
         */

        switch (freq->rcv_rsplen) {

        case 0:
        case NVME_FC_SIZEOF_ZEROS_RSP:
                /*
                 * No response payload or 12 bytes of payload (which
                 * should all be zeros) are considered successful and
                 * no payload in the CQE by the transport.
                 */
                if (freq->transferred_length !=
                    be32_to_cpu(op->cmd_iu.data_len)) {
                        status = cpu_to_le16(NVME_SC_HOST_PATH_ERROR << 1);
                        dev_info(ctrl->ctrl.device,
                                "NVME-FC{%d}: io failed due to bad transfer "
                                "length: %d vs expected %d\n",
                                ctrl->cnum, freq->transferred_length,
                                be32_to_cpu(op->cmd_iu.data_len));
                        goto done;
                }
                result.u64 = 0;
                break;

        case sizeof(struct nvme_fc_ersp_iu):
                /*
                 * The ERSP IU contains a full completion with CQE.
                 * Validate ERSP IU and look at cqe.
                 */
                if (unlikely(be16_to_cpu(op->rsp_iu.iu_len) !=
                                        (freq->rcv_rsplen / 4) ||
                             be32_to_cpu(op->rsp_iu.xfrd_len) !=
                                        freq->transferred_length ||
                             op->rsp_iu.ersp_result ||
                             sqe->common.command_id != cqe->command_id)) {
                        status = cpu_to_le16(NVME_SC_HOST_PATH_ERROR << 1);
                        dev_info(ctrl->ctrl.device,
                                "NVME-FC{%d}: io failed due to bad NVMe_ERSP: "
                                "iu len %d, xfr len %d vs %d, status code "
                                "%d, cmdid %d vs %d\n",
                                ctrl->cnum, be16_to_cpu(op->rsp_iu.iu_len),
                                be32_to_cpu(op->rsp_iu.xfrd_len),
                                freq->transferred_length,
                                op->rsp_iu.ersp_result,
                                sqe->common.command_id,
                                cqe->command_id);
                        goto done;
                }
                result = cqe->result;
                status = cqe->status;
                break;

        default:
                status = cpu_to_le16(NVME_SC_HOST_PATH_ERROR << 1);
                dev_info(ctrl->ctrl.device,
                        "NVME-FC{%d}: io failed due to odd NVMe_xRSP iu "
                        "len %d\n",
                        ctrl->cnum, freq->rcv_rsplen);
                goto done;
        }

        terminate_assoc = false;

done:
        if (op->flags & FCOP_FLAGS_AEN) {
                nvme_complete_async_event(&queue->ctrl->ctrl, status, &result);
                __nvme_fc_fcpop_chk_teardowns(ctrl, op, opstate);
                atomic_set(&op->state, FCPOP_STATE_IDLE);
                op->flags = FCOP_FLAGS_AEN;     /* clear other flags */
                nvme_fc_ctrl_put(ctrl);
                goto check_error;
        }

        __nvme_fc_fcpop_chk_teardowns(ctrl, op, opstate);
        nvme_end_request(rq, status, result);

check_error:
        if (terminate_assoc)
                nvme_fc_error_recovery(ctrl, "transport detected io error");
}

static int
__nvme_fc_init_request(struct nvme_fc_ctrl *ctrl,
                struct nvme_fc_queue *queue, struct nvme_fc_fcp_op *op,
                struct request *rq, u32 rqno)
{
        struct nvme_fcp_op_w_sgl *op_w_sgl =
                container_of(op, typeof(*op_w_sgl), op);
        struct nvme_fc_cmd_iu *cmdiu = &op->cmd_iu;
        int ret = 0;

        memset(op, 0, sizeof(*op));
        op->fcp_req.cmdaddr = &op->cmd_iu;
        op->fcp_req.cmdlen = sizeof(op->cmd_iu);
        op->fcp_req.rspaddr = &op->rsp_iu;
        op->fcp_req.rsplen = sizeof(op->rsp_iu);
        op->fcp_req.done = nvme_fc_fcpio_done;
        op->ctrl = ctrl;
        op->queue = queue;
        op->rq = rq;
        op->rqno = rqno;

        cmdiu->format_id = NVME_CMD_FORMAT_ID;
        cmdiu->fc_id = NVME_CMD_FC_ID;
        cmdiu->iu_len = cpu_to_be16(sizeof(*cmdiu) / sizeof(u32));
        if (queue->qnum)
                cmdiu->rsv_cat = fccmnd_set_cat_css(0,
                                        (NVME_CC_CSS_NVM >> NVME_CC_CSS_SHIFT));
        else
                cmdiu->rsv_cat = fccmnd_set_cat_admin(0);

        op->fcp_req.cmddma = fc_dma_map_single(ctrl->lport->dev,
                                &op->cmd_iu, sizeof(op->cmd_iu), DMA_TO_DEVICE);
        if (fc_dma_mapping_error(ctrl->lport->dev, op->fcp_req.cmddma)) {
                dev_err(ctrl->dev,
                        "FCP Op failed - cmdiu dma mapping failed.\n");
                ret = EFAULT;
                goto out_on_error;
        }

        op->fcp_req.rspdma = fc_dma_map_single(ctrl->lport->dev,
                                &op->rsp_iu, sizeof(op->rsp_iu),
                                DMA_FROM_DEVICE);
        if (fc_dma_mapping_error(ctrl->lport->dev, op->fcp_req.rspdma)) {
                dev_err(ctrl->dev,
                        "FCP Op failed - rspiu dma mapping failed.\n");
                ret = EFAULT;
        }

        atomic_set(&op->state, FCPOP_STATE_IDLE);
out_on_error:
        return ret;
}

static int
nvme_fc_init_request(struct blk_mq_tag_set *set, struct request *rq,
                unsigned int hctx_idx, unsigned int numa_node)
{
        struct nvme_fc_ctrl *ctrl = set->driver_data;
        struct nvme_fcp_op_w_sgl *op = blk_mq_rq_to_pdu(rq);
        int queue_idx = (set == &ctrl->tag_set) ? hctx_idx + 1 : 0;
        struct nvme_fc_queue *queue = &ctrl->queues[queue_idx];
        int res;

        res = __nvme_fc_init_request(ctrl, queue, &op->op, rq, queue->rqcnt++);
        if (res)
                return res;
        op->op.fcp_req.first_sgl = &op->sgl[0];
        op->op.fcp_req.private = &op->priv[0];
        nvme_req(rq)->ctrl = &ctrl->ctrl;
        return res;
}

static int
nvme_fc_init_aen_ops(struct nvme_fc_ctrl *ctrl)
{
        struct nvme_fc_fcp_op *aen_op;
        struct nvme_fc_cmd_iu *cmdiu;
        struct nvme_command *sqe;
        void *private;
        int i, ret;

        aen_op = ctrl->aen_ops;
        for (i = 0; i < NVME_NR_AEN_COMMANDS; i++, aen_op++) {
                private = kzalloc(ctrl->lport->ops->fcprqst_priv_sz,
                                                GFP_KERNEL);
                if (!private)
                        return -ENOMEM;

                cmdiu = &aen_op->cmd_iu;
                sqe = &cmdiu->sqe;
                ret = __nvme_fc_init_request(ctrl, &ctrl->queues[0],
                                aen_op, (struct request *)NULL,
                                (NVME_AQ_BLK_MQ_DEPTH + i));
                if (ret) {
                        kfree(private);
                        return ret;
                }

                aen_op->flags = FCOP_FLAGS_AEN;
                aen_op->fcp_req.private = private;

                memset(sqe, 0, sizeof(*sqe));
                sqe->common.opcode = nvme_admin_async_event;
                /* Note: core layer may overwrite the sqe.command_id value */
                sqe->common.command_id = NVME_AQ_BLK_MQ_DEPTH + i;
        }
        return 0;
}

static void
nvme_fc_term_aen_ops(struct nvme_fc_ctrl *ctrl)
{
        struct nvme_fc_fcp_op *aen_op;
        int i;

        aen_op = ctrl->aen_ops;
        for (i = 0; i < NVME_NR_AEN_COMMANDS; i++, aen_op++) {
                if (!aen_op->fcp_req.private)
                        continue;

                __nvme_fc_exit_request(ctrl, aen_op);

                kfree(aen_op->fcp_req.private);
                aen_op->fcp_req.private = NULL;
        }
}

static inline void
__nvme_fc_init_hctx(struct blk_mq_hw_ctx *hctx, struct nvme_fc_ctrl *ctrl,
                unsigned int qidx)
{
        struct nvme_fc_queue *queue = &ctrl->queues[qidx];

        hctx->driver_data = queue;
        queue->hctx = hctx;
}

static int
nvme_fc_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
                unsigned int hctx_idx)
{
        struct nvme_fc_ctrl *ctrl = data;

        __nvme_fc_init_hctx(hctx, ctrl, hctx_idx + 1);

        return 0;
}

static int
nvme_fc_init_admin_hctx(struct blk_mq_hw_ctx *hctx, void *data,
                unsigned int hctx_idx)
{
        struct nvme_fc_ctrl *ctrl = data;

        __nvme_fc_init_hctx(hctx, ctrl, hctx_idx);

        return 0;
}

static void
nvme_fc_init_queue(struct nvme_fc_ctrl *ctrl, int idx)
{
        struct nvme_fc_queue *queue;

        queue = &ctrl->queues[idx];
        memset(queue, 0, sizeof(*queue));
        queue->ctrl = ctrl;
        queue->qnum = idx;
        atomic_set(&queue->csn, 0);
        queue->dev = ctrl->dev;

        if (idx > 0)
                queue->cmnd_capsule_len = ctrl->ctrl.ioccsz * 16;
        else
                queue->cmnd_capsule_len = sizeof(struct nvme_command);

        /*
         * Considered whether we should allocate buffers for all SQEs
         * and CQEs and dma map them - mapping their respective entries
         * into the request structures (kernel vm addr and dma address)
         * thus the driver could use the buffers/mappings directly.
         * It only makes sense if the LLDD would use them for its
         * messaging api. It's very unlikely most adapter api's would use
         * a native NVME sqe/cqe. More reasonable if FC-NVME IU payload
         * structures were used instead.
         */
}

/*
 * This routine terminates a queue at the transport level.
 * The transport has already ensured that all outstanding ios on
 * the queue have been terminated.
 * The transport will send a Disconnect LS request to terminate
 * the queue's connection. Termination of the admin queue will also
 * terminate the association at the target.
 */
static void
nvme_fc_free_queue(struct nvme_fc_queue *queue)
{
        if (!test_and_clear_bit(NVME_FC_Q_CONNECTED, &queue->flags))
                return;

        clear_bit(NVME_FC_Q_LIVE, &queue->flags);
        /*
         * Current implementation never disconnects a single queue.
         * It always terminates a whole association. So there is never
         * a disconnect(queue) LS sent to the target.
         */

        queue->connection_id = 0;
        atomic_set(&queue->csn, 0);
}

static void
__nvme_fc_delete_hw_queue(struct nvme_fc_ctrl *ctrl,
        struct nvme_fc_queue *queue, unsigned int qidx)
{
        if (ctrl->lport->ops->delete_queue)
                ctrl->lport->ops->delete_queue(&ctrl->lport->localport, qidx,
                                queue->lldd_handle);
        queue->lldd_handle = NULL;
}

static void
nvme_fc_free_io_queues(struct nvme_fc_ctrl *ctrl)
{
        int i;

        for (i = 1; i < ctrl->ctrl.queue_count; i++)
                nvme_fc_free_queue(&ctrl->queues[i]);
}

static int
__nvme_fc_create_hw_queue(struct nvme_fc_ctrl *ctrl,
        struct nvme_fc_queue *queue, unsigned int qidx, u16 qsize)
{
        int ret = 0;

        queue->lldd_handle = NULL;
        if (ctrl->lport->ops->create_queue)
                ret = ctrl->lport->ops->create_queue(&ctrl->lport->localport,
                                qidx, qsize, &queue->lldd_handle);

        return ret;
}

static void
nvme_fc_delete_hw_io_queues(struct nvme_fc_ctrl *ctrl)
{
        struct nvme_fc_queue *queue = &ctrl->queues[ctrl->ctrl.queue_count - 1];
        int i;

        for (i = ctrl->ctrl.queue_count - 1; i >= 1; i--, queue--)
                __nvme_fc_delete_hw_queue(ctrl, queue, i);
}

static int
nvme_fc_create_hw_io_queues(struct nvme_fc_ctrl *ctrl, u16 qsize)
{
        struct nvme_fc_queue *queue = &ctrl->queues[1];
        int i, ret;

        for (i = 1; i < ctrl->ctrl.queue_count; i++, queue++) {
                ret = __nvme_fc_create_hw_queue(ctrl, queue, i, qsize);
                if (ret)
                        goto delete_queues;
        }

        return 0;

delete_queues:
        for (; i >= 0; i--)
                __nvme_fc_delete_hw_queue(ctrl, &ctrl->queues[i], i);
        return ret;
}

static int
nvme_fc_connect_io_queues(struct nvme_fc_ctrl *ctrl, u16 qsize)
{
        int i, ret = 0;

        for (i = 1; i < ctrl->ctrl.queue_count; i++) {
                ret = nvme_fc_connect_queue(ctrl, &ctrl->queues[i], qsize,
                                        (qsize / 5));
                if (ret)
                        break;
                ret = nvmf_connect_io_queue(&ctrl->ctrl, i, false);
                if (ret)
                        break;

                set_bit(NVME_FC_Q_LIVE, &ctrl->queues[i].flags);
        }

        return ret;
}

static void
nvme_fc_init_io_queues(struct nvme_fc_ctrl *ctrl)
{
        int i;

        for (i = 1; i < ctrl->ctrl.queue_count; i++)
                nvme_fc_init_queue(ctrl, i);
}

static void
nvme_fc_ctrl_free(struct kref *ref)
{
        struct nvme_fc_ctrl *ctrl =
                container_of(ref, struct nvme_fc_ctrl, ref);
        struct nvme_fc_lport *lport = ctrl->lport;
        unsigned long flags;

        if (ctrl->ctrl.tagset) {
                blk_cleanup_queue(ctrl->ctrl.connect_q);
                blk_mq_free_tag_set(&ctrl->tag_set);
        }

        /* remove from rport list */
        spin_lock_irqsave(&ctrl->rport->lock, flags);
        list_del(&ctrl->ctrl_list);
        spin_unlock_irqrestore(&ctrl->rport->lock, flags);

        blk_mq_unquiesce_queue(ctrl->ctrl.admin_q);
        blk_cleanup_queue(ctrl->ctrl.admin_q);
        blk_cleanup_queue(ctrl->ctrl.fabrics_q);
        blk_mq_free_tag_set(&ctrl->admin_tag_set);

        kfree(ctrl->queues);

        put_device(ctrl->dev);
        nvme_fc_rport_put(ctrl->rport);

        ida_simple_remove(&nvme_fc_ctrl_cnt, ctrl->cnum);
        if (ctrl->ctrl.opts)
                nvmf_free_options(ctrl->ctrl.opts);
        kfree(ctrl);
        module_put(lport->ops->module);
}

static void
nvme_fc_ctrl_put(struct nvme_fc_ctrl *ctrl)
{
        kref_put(&ctrl->ref, nvme_fc_ctrl_free);
}

static int
nvme_fc_ctrl_get(struct nvme_fc_ctrl *ctrl)
{
        return kref_get_unless_zero(&ctrl->ref);
}

/*
 * All accesses from nvme core layer done - can now free the
 * controller. Called after last nvme_put_ctrl() call
 */
static void
nvme_fc_nvme_ctrl_freed(struct nvme_ctrl *nctrl)
{
        struct nvme_fc_ctrl *ctrl = to_fc_ctrl(nctrl);

        WARN_ON(nctrl != &ctrl->ctrl);

        nvme_fc_ctrl_put(ctrl);
}

static void
nvme_fc_error_recovery(struct nvme_fc_ctrl *ctrl, char *errmsg)
{
        int active;

        /*
         * if an error (io timeout, etc) while (re)connecting,
         * it's an error on creating the new association.
         * Start the error recovery thread if it hasn't already
         * been started. It is expected there could be multiple
         * ios hitting this path before things are cleaned up.
         */
        if (ctrl->ctrl.state == NVME_CTRL_CONNECTING) {
                active = atomic_xchg(&ctrl->err_work_active, 1);
                if (!active && !queue_work(nvme_fc_wq, &ctrl->err_work)) {
                        atomic_set(&ctrl->err_work_active, 0);
                        WARN_ON(1);
                }
                return;
        }

        /* Otherwise, only proceed if in LIVE state - e.g. on first error */
        if (ctrl->ctrl.state != NVME_CTRL_LIVE)
                return;

        dev_warn(ctrl->ctrl.device,
                "NVME-FC{%d}: transport association error detected: %s\n",
                ctrl->cnum, errmsg);
        dev_warn(ctrl->ctrl.device,
                "NVME-FC{%d}: resetting controller\n", ctrl->cnum);

        nvme_reset_ctrl(&ctrl->ctrl);
}

static enum blk_eh_timer_return
nvme_fc_timeout(struct request *rq, bool reserved)
{
        struct nvme_fc_fcp_op *op = blk_mq_rq_to_pdu(rq);
        struct nvme_fc_ctrl *ctrl = op->ctrl;

        /*
         * we can't individually ABTS an io without affecting the queue,
         * thus killing the queue, and thus the association.
         * So resolve by performing a controller reset, which will stop
         * the host/io stack, terminate the association on the link,
         * and recreate an association on the link.
         */
        nvme_fc_error_recovery(ctrl, "io timeout error");

        /*
         * the io abort has been initiated. Have the reset timer
         * restarted and the abort completion will complete the io
         * shortly. Avoids a synchronous wait while the abort finishes.
         */
        return BLK_EH_RESET_TIMER;
}

static int
nvme_fc_map_data(struct nvme_fc_ctrl *ctrl, struct request *rq,
                struct nvme_fc_fcp_op *op)
{
        struct nvmefc_fcp_req *freq = &op->fcp_req;
        int ret;

        freq->sg_cnt = 0;

        if (!blk_rq_nr_phys_segments(rq))
                return 0;

        freq->sg_table.sgl = freq->first_sgl;
        ret = sg_alloc_table_chained(&freq->sg_table,
                        blk_rq_nr_phys_segments(rq), freq->sg_table.sgl,
                        NVME_INLINE_SG_CNT);
        if (ret)
                return -ENOMEM;

        op->nents = blk_rq_map_sg(rq->q, rq, freq->sg_table.sgl);
        WARN_ON(op->nents > blk_rq_nr_phys_segments(rq));
        freq->sg_cnt = fc_dma_map_sg(ctrl->lport->dev, freq->sg_table.sgl,
                                op->nents, rq_dma_dir(rq));
        if (unlikely(freq->sg_cnt <= 0)) {
                sg_free_table_chained(&freq->sg_table, NVME_INLINE_SG_CNT);
                freq->sg_cnt = 0;
                return -EFAULT;
        }

        /*
         * TODO: blk_integrity_rq(rq)  for DIF
         */
        return 0;
}

static void
nvme_fc_unmap_data(struct nvme_fc_ctrl *ctrl, struct request *rq,
                struct nvme_fc_fcp_op *op)
{
        struct nvmefc_fcp_req *freq = &op->fcp_req;

        if (!freq->sg_cnt)
                return;

        fc_dma_unmap_sg(ctrl->lport->dev, freq->sg_table.sgl, op->nents,
                        rq_dma_dir(rq));

        sg_free_table_chained(&freq->sg_table, NVME_INLINE_SG_CNT);

        freq->sg_cnt = 0;
}

/*
 * In FC, the queue is a logical thing. At transport connect, the target
 * creates its "queue" and returns a handle that is to be given to the
 * target whenever it posts something to the corresponding SQ.  When an
 * SQE is sent on a SQ, FC effectively considers the SQE, or rather the
 * command contained within the SQE, an io, and assigns a FC exchange
 * to it. The SQE and the associated SQ handle are sent in the initial
 * CMD IU sents on the exchange. All transfers relative to the io occur
 * as part of the exchange.  The CQE is the last thing for the io,
 * which is transferred (explicitly or implicitly) with the RSP IU
 * sent on the exchange. After the CQE is received, the FC exchange is
 * terminaed and the Exchange may be used on a different io.
 *
 * The transport to LLDD api has the transport making a request for a
 * new fcp io request to the LLDD. The LLDD then allocates a FC exchange
 * resource and transfers the command. The LLDD will then process all
 * steps to complete the io. Upon completion, the transport done routine
 * is called.
 *
 * So - while the operation is outstanding to the LLDD, there is a link
 * level FC exchange resource that is also outstanding. This must be
 * considered in all cleanup operations.
 */
static blk_status_t
nvme_fc_start_fcp_op(struct nvme_fc_ctrl *ctrl, struct nvme_fc_queue *queue,
        struct nvme_fc_fcp_op *op, u32 data_len,
        enum nvmefc_fcp_datadir io_dir)
{
        struct nvme_fc_cmd_iu *cmdiu = &op->cmd_iu;
        struct nvme_command *sqe = &cmdiu->sqe;
        int ret, opstate;

        /*
         * before attempting to send the io, check to see if we believe
         * the target device is present
         */
        if (ctrl->rport->remoteport.port_state != FC_OBJSTATE_ONLINE)
                return BLK_STS_RESOURCE;

        if (!nvme_fc_ctrl_get(ctrl))
                return BLK_STS_IOERR;

        /* format the FC-NVME CMD IU and fcp_req */
        cmdiu->connection_id = cpu_to_be64(queue->connection_id);
        cmdiu->data_len = cpu_to_be32(data_len);
        switch (io_dir) {
        case NVMEFC_FCP_WRITE:
                cmdiu->flags = FCNVME_CMD_FLAGS_WRITE;
                break;
        case NVMEFC_FCP_READ:
                cmdiu->flags = FCNVME_CMD_FLAGS_READ;
                break;
        case NVMEFC_FCP_NODATA:
                cmdiu->flags = 0;
                break;
        }
        op->fcp_req.payload_length = data_len;
        op->fcp_req.io_dir = io_dir;
        op->fcp_req.transferred_length = 0;
        op->fcp_req.rcv_rsplen = 0;
        op->fcp_req.status = NVME_SC_SUCCESS;
        op->fcp_req.sqid = cpu_to_le16(queue->qnum);

        /*
         * validate per fabric rules, set fields mandated by fabric spec
         * as well as those by FC-NVME spec.
         */
        WARN_ON_ONCE(sqe->common.metadata);
        sqe->common.flags |= NVME_CMD_SGL_METABUF;

        /*
         * format SQE DPTR field per FC-NVME rules:
         *    type=0x5     Transport SGL Data Block Descriptor
         *    subtype=0xA  Transport-specific value
         *    address=0
         *    length=length of the data series
         */
        sqe->rw.dptr.sgl.type = (NVME_TRANSPORT_SGL_DATA_DESC << 4) |
                                        NVME_SGL_FMT_TRANSPORT_A;
        sqe->rw.dptr.sgl.length = cpu_to_le32(data_len);
        sqe->rw.dptr.sgl.addr = 0;

        if (!(op->flags & FCOP_FLAGS_AEN)) {
                ret = nvme_fc_map_data(ctrl, op->rq, op);
                if (ret < 0) {
                        nvme_cleanup_cmd(op->rq);
                        nvme_fc_ctrl_put(ctrl);
                        if (ret == -ENOMEM || ret == -EAGAIN)
                                return BLK_STS_RESOURCE;
                        return BLK_STS_IOERR;
                }
        }

        fc_dma_sync_single_for_device(ctrl->lport->dev, op->fcp_req.cmddma,
                                  sizeof(op->cmd_iu), DMA_TO_DEVICE);

        atomic_set(&op->state, FCPOP_STATE_ACTIVE);

        if (!(op->flags & FCOP_FLAGS_AEN))
                blk_mq_start_request(op->rq);

        cmdiu->csn = cpu_to_be32(atomic_inc_return(&queue->csn));
        ret = ctrl->lport->ops->fcp_io(&ctrl->lport->localport,
                                        &ctrl->rport->remoteport,
                                        queue->lldd_handle, &op->fcp_req);

        if (ret) {
                /*
                 * If the lld fails to send the command is there an issue with
                 * the csn value?  If the command that fails is the Connect,
                 * no - as the connection won't be live.  If it is a command
                 * post-connect, it's possible a gap in csn may be created.
                 * Does this matter?  As Linux initiators don't send fused
                 * commands, no.  The gap would exist, but as there's nothing
                 * that depends on csn order to be delivered on the target
                 * side, it shouldn't hurt.  It would be difficult for a
                 * target to even detect the csn gap as it has no idea when the
                 * cmd with the csn was supposed to arrive.
                 */
                opstate = atomic_xchg(&op->state, FCPOP_STATE_COMPLETE);
                __nvme_fc_fcpop_chk_teardowns(ctrl, op, opstate);

                if (!(op->flags & FCOP_FLAGS_AEN))
                        nvme_fc_unmap_data(ctrl, op->rq, op);

                nvme_cleanup_cmd(op->rq);
                nvme_fc_ctrl_put(ctrl);

                if (ctrl->rport->remoteport.port_state == FC_OBJSTATE_ONLINE &&
                                ret != -EBUSY)
                        return BLK_STS_IOERR;

                return BLK_STS_RESOURCE;
        }

        return BLK_STS_OK;
}

static blk_status_t
nvme_fc_queue_rq(struct blk_mq_hw_ctx *hctx,
                        const struct blk_mq_queue_data *bd)
{
        struct nvme_ns *ns = hctx->queue->queuedata;
        struct nvme_fc_queue *queue = hctx->driver_data;
        struct nvme_fc_ctrl *ctrl = queue->ctrl;
        struct request *rq = bd->rq;
        struct nvme_fc_fcp_op *op = blk_mq_rq_to_pdu(rq);
        struct nvme_fc_cmd_iu *cmdiu = &op->cmd_iu;
        struct nvme_command *sqe = &cmdiu->sqe;
        enum nvmefc_fcp_datadir io_dir;
        bool queue_ready = test_bit(NVME_FC_Q_LIVE, &queue->flags);
        u32 data_len;
        blk_status_t ret;

        if (ctrl->rport->remoteport.port_state != FC_OBJSTATE_ONLINE ||
            !nvmf_check_ready(&queue->ctrl->ctrl, rq, queue_ready))
                return nvmf_fail_nonready_command(&queue->ctrl->ctrl, rq);

        ret = nvme_setup_cmd(ns, rq, sqe);
        if (ret)
                return ret;

        /*
         * nvme core doesn't quite treat the rq opaquely. Commands such
         * as WRITE ZEROES will return a non-zero rq payload_bytes yet
         * there is no actual payload to be transferred.
         * To get it right, key data transmission on there being 1 or
         * more physical segments in the sg list. If there is no
         * physical segments, there is no payload.
         */
        if (blk_rq_nr_phys_segments(rq)) {
                data_len = blk_rq_payload_bytes(rq);
                io_dir = ((rq_data_dir(rq) == WRITE) ?
                                        NVMEFC_FCP_WRITE : NVMEFC_FCP_READ);
        } else {
                data_len = 0;
                io_dir = NVMEFC_FCP_NODATA;
        }


        return nvme_fc_start_fcp_op(ctrl, queue, op, data_len, io_dir);
}

static void
nvme_fc_submit_async_event(struct nvme_ctrl *arg)
{
        struct nvme_fc_ctrl *ctrl = to_fc_ctrl(arg);
        struct nvme_fc_fcp_op *aen_op;
        unsigned long flags;
        bool terminating = false;
        blk_status_t ret;

        spin_lock_irqsave(&ctrl->lock, flags);
        if (ctrl->flags & FCCTRL_TERMIO)
                terminating = true;
        spin_unlock_irqrestore(&ctrl->lock, flags);

        if (terminating)
                return;

        aen_op = &ctrl->aen_ops[0];

        ret = nvme_fc_start_fcp_op(ctrl, aen_op->queue, aen_op, 0,
                                        NVMEFC_FCP_NODATA);
        if (ret)
                dev_err(ctrl->ctrl.device,
                        "failed async event work\n");
}

static void
nvme_fc_complete_rq(struct request *rq)
{
        struct nvme_fc_fcp_op *op = blk_mq_rq_to_pdu(rq);
        struct nvme_fc_ctrl *ctrl = op->ctrl;

        atomic_set(&op->state, FCPOP_STATE_IDLE);

        nvme_fc_unmap_data(ctrl, rq, op);
        nvme_complete_rq(rq);
        nvme_fc_ctrl_put(ctrl);
}

/*
 * This routine is used by the transport when it needs to find active
 * io on a queue that is to be terminated. The transport uses
 * blk_mq_tagset_busy_itr() to find the busy requests, which then invoke
 * this routine to kill them on a 1 by 1 basis.
 *
 * As FC allocates FC exchange for each io, the transport must contact
 * the LLDD to terminate the exchange, thus releasing the FC exchange.
 * After terminating the exchange the LLDD will call the transport's
 * normal io done path for the request, but it will have an aborted
 * status. The done path will return the io request back to the block
 * layer with an error status.
 */
static bool
nvme_fc_terminate_exchange(struct request *req, void *data, bool reserved)
{
        struct nvme_ctrl *nctrl = data;
        struct nvme_fc_ctrl *ctrl = to_fc_ctrl(nctrl);
        struct nvme_fc_fcp_op *op = blk_mq_rq_to_pdu(req);

        __nvme_fc_abort_op(ctrl, op);
        return true;
}


static const struct blk_mq_ops nvme_fc_mq_ops = {
        .queue_rq       = nvme_fc_queue_rq,
        .complete       = nvme_fc_complete_rq,
        .init_request   = nvme_fc_init_request,
        .exit_request   = nvme_fc_exit_request,
        .init_hctx      = nvme_fc_init_hctx,
        .timeout        = nvme_fc_timeout,
};

static int
nvme_fc_create_io_queues(struct nvme_fc_ctrl *ctrl)
{
        struct nvmf_ctrl_options *opts = ctrl->ctrl.opts;
        unsigned int nr_io_queues;
        int ret;

        nr_io_queues = min(min(opts->nr_io_queues, num_online_cpus()),
                                ctrl->lport->ops->max_hw_queues);
        ret = nvme_set_queue_count(&ctrl->ctrl, &nr_io_queues);
        if (ret) {
                dev_info(ctrl->ctrl.device,
                        "set_queue_count failed: %d\n", ret);
                return ret;
        }

        ctrl->ctrl.queue_count = nr_io_queues + 1;
        if (!nr_io_queues)
                return 0;

        nvme_fc_init_io_queues(ctrl);

        memset(&ctrl->tag_set, 0, sizeof(ctrl->tag_set));
        ctrl->tag_set.ops = &nvme_fc_mq_ops;
        ctrl->tag_set.queue_depth = ctrl->ctrl.opts->queue_size;
        ctrl->tag_set.reserved_tags = 1; /* fabric connect */
        ctrl->tag_set.numa_node = ctrl->ctrl.numa_node;
        ctrl->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
        ctrl->tag_set.cmd_size =
                struct_size((struct nvme_fcp_op_w_sgl *)NULL, priv,
                            ctrl->lport->ops->fcprqst_priv_sz);
        ctrl->tag_set.driver_data = ctrl;
        ctrl->tag_set.nr_hw_queues = ctrl->ctrl.queue_count - 1;
        ctrl->tag_set.timeout = NVME_IO_TIMEOUT;

        ret = blk_mq_alloc_tag_set(&ctrl->tag_set);
        if (ret)
                return ret;

        ctrl->ctrl.tagset = &ctrl->tag_set;

        ctrl->ctrl.connect_q = blk_mq_init_queue(&ctrl->tag_set);
        if (IS_ERR(ctrl->ctrl.connect_q)) {
                ret = PTR_ERR(ctrl->ctrl.connect_q);
                goto out_free_tag_set;
        }

        ret = nvme_fc_create_hw_io_queues(ctrl, ctrl->ctrl.sqsize + 1);
        if (ret)
                goto out_cleanup_blk_queue;

        ret = nvme_fc_connect_io_queues(ctrl, ctrl->ctrl.sqsize + 1);
        if (ret)
                goto out_delete_hw_queues;

        ctrl->ioq_live = true;

        return 0;

out_delete_hw_queues:
        nvme_fc_delete_hw_io_queues(ctrl);
out_cleanup_blk_queue:
        blk_cleanup_queue(ctrl->ctrl.connect_q);
out_free_tag_set:
        blk_mq_free_tag_set(&ctrl->tag_set);
        nvme_fc_free_io_queues(ctrl);

        /* force put free routine to ignore io queues */
        ctrl->ctrl.tagset = NULL;

        return ret;
}

static int
nvme_fc_recreate_io_queues(struct nvme_fc_ctrl *ctrl)
{
        struct nvmf_ctrl_options *opts = ctrl->ctrl.opts;
        u32 prior_ioq_cnt = ctrl->ctrl.queue_count - 1;
        unsigned int nr_io_queues;
        int ret;

        nr_io_queues = min(min(opts->nr_io_queues, num_online_cpus()),
                                ctrl->lport->ops->max_hw_queues);
        ret = nvme_set_queue_count(&ctrl->ctrl, &nr_io_queues);
        if (ret) {
                dev_info(ctrl->ctrl.device,
                        "set_queue_count failed: %d\n", ret);
                return ret;
        }

        if (!nr_io_queues && prior_ioq_cnt) {
                dev_info(ctrl->ctrl.device,
                        "Fail Reconnect: At least 1 io queue "
                        "required (was %d)\n", prior_ioq_cnt);
                return -ENOSPC;
        }

        ctrl->ctrl.queue_count = nr_io_queues + 1;
        /* check for io queues existing */
        if (ctrl->ctrl.queue_count == 1)
                return 0;

        ret = nvme_fc_create_hw_io_queues(ctrl, ctrl->ctrl.sqsize + 1);
        if (ret)
                goto out_free_io_queues;

        ret = nvme_fc_connect_io_queues(ctrl, ctrl->ctrl.sqsize + 1);
        if (ret)
                goto out_delete_hw_queues;

        if (prior_ioq_cnt != nr_io_queues)
                dev_info(ctrl->ctrl.device,
                        "reconnect: revising io queue count from %d to %d\n",
                        prior_ioq_cnt, nr_io_queues);
        blk_mq_update_nr_hw_queues(&ctrl->tag_set, nr_io_queues);

        return 0;

out_delete_hw_queues:
        nvme_fc_delete_hw_io_queues(ctrl);
out_free_io_queues:
        nvme_fc_free_io_queues(ctrl);
        return ret;
}

static void
nvme_fc_rport_active_on_lport(struct nvme_fc_rport *rport)
{
        struct nvme_fc_lport *lport = rport->lport;

        atomic_inc(&lport->act_rport_cnt);
}

static void
nvme_fc_rport_inactive_on_lport(struct nvme_fc_rport *rport)
{
        struct nvme_fc_lport *lport = rport->lport;
        u32 cnt;

        cnt = atomic_dec_return(&lport->act_rport_cnt);
        if (cnt == 0 && lport->localport.port_state == FC_OBJSTATE_DELETED)
                lport->ops->localport_delete(&lport->localport);
}

static int
nvme_fc_ctlr_active_on_rport(struct nvme_fc_ctrl *ctrl)
{
        struct nvme_fc_rport *rport = ctrl->rport;
        u32 cnt;

        if (ctrl->assoc_active)
                return 1;

        ctrl->assoc_active = true;
        cnt = atomic_inc_return(&rport->act_ctrl_cnt);
        if (cnt == 1)
                nvme_fc_rport_active_on_lport(rport);

        return 0;
}

static int
nvme_fc_ctlr_inactive_on_rport(struct nvme_fc_ctrl *ctrl)
{
        struct nvme_fc_rport *rport = ctrl->rport;
        struct nvme_fc_lport *lport = rport->lport;
        u32 cnt;

        /* ctrl->assoc_active=false will be set independently */

        cnt = atomic_dec_return(&rport->act_ctrl_cnt);
        if (cnt == 0) {
                if (rport->remoteport.port_state == FC_OBJSTATE_DELETED)
                        lport->ops->remoteport_delete(&rport->remoteport);
                nvme_fc_rport_inactive_on_lport(rport);
        }

        return 0;
}

/*
 * This routine restarts the controller on the host side, and
 * on the link side, recreates the controller association.
 */
static int
nvme_fc_create_association(struct nvme_fc_ctrl *ctrl)
{
        struct nvmf_ctrl_options *opts = ctrl->ctrl.opts;
        int ret;
        bool changed;

        ++ctrl->ctrl.nr_reconnects;

        if (ctrl->rport->remoteport.port_state != FC_OBJSTATE_ONLINE)
                return -ENODEV;

        if (nvme_fc_ctlr_active_on_rport(ctrl))
                return -ENOTUNIQ;

        dev_info(ctrl->ctrl.device,
                "NVME-FC{%d}: create association : host wwpn 0x%016llx "
                " rport wwpn 0x%016llx: NQN \"%s\"\n",
                ctrl->cnum, ctrl->lport->localport.port_name,
                ctrl->rport->remoteport.port_name, ctrl->ctrl.opts->subsysnqn);

        /*
         * Create the admin queue
         */

        ret = __nvme_fc_create_hw_queue(ctrl, &ctrl->queues[0], 0,
                                NVME_AQ_DEPTH);
        if (ret)
                goto out_free_queue;

        ret = nvme_fc_connect_admin_queue(ctrl, &ctrl->queues[0],
                                NVME_AQ_DEPTH, (NVME_AQ_DEPTH / 4));
        if (ret)
                goto out_delete_hw_queue;

        ret = nvmf_connect_admin_queue(&ctrl->ctrl);
        if (ret)
                goto out_disconnect_admin_queue;

        set_bit(NVME_FC_Q_LIVE, &ctrl->queues[0].flags);

        /*
         * Check controller capabilities
         *
         * todo:- add code to check if ctrl attributes changed from
         * prior connection values
         */

        ret = nvme_enable_ctrl(&ctrl->ctrl);
        if (ret)
                goto out_disconnect_admin_queue;

        ctrl->ctrl.max_hw_sectors =
                (ctrl->lport->ops->max_sgl_segments - 1) << (PAGE_SHIFT - 9);

        blk_mq_unquiesce_queue(ctrl->ctrl.admin_q);

        ret = nvme_init_identify(&ctrl->ctrl);
        if (ret)
                goto out_disconnect_admin_queue;

        /* sanity checks */

        /* FC-NVME does not have other data in the capsule */
        if (ctrl->ctrl.icdoff) {
                dev_err(ctrl->ctrl.device, "icdoff %d is not supported!\n",
                                ctrl->ctrl.icdoff);
                goto out_disconnect_admin_queue;
        }

        /* FC-NVME supports normal SGL Data Block Descriptors */

        if (opts->queue_size > ctrl->ctrl.maxcmd) {
                /* warn if maxcmd is lower than queue_size */
                dev_warn(ctrl->ctrl.device,
                        "queue_size %zu > ctrl maxcmd %u, reducing "
                        "to maxcmd\n",
                        opts->queue_size, ctrl->ctrl.maxcmd);
                opts->queue_size = ctrl->ctrl.maxcmd;
        }

        if (opts->queue_size > ctrl->ctrl.sqsize + 1) {
                /* warn if sqsize is lower than queue_size */
                dev_warn(ctrl->ctrl.device,
                        "queue_size %zu > ctrl sqsize %u, reducing "
                        "to sqsize\n",
                        opts->queue_size, ctrl->ctrl.sqsize + 1);
                opts->queue_size = ctrl->ctrl.sqsize + 1;
        }

        ret = nvme_fc_init_aen_ops(ctrl);
        if (ret)
                goto out_term_aen_ops;

        /*
         * Create the io queues
         */

        if (ctrl->ctrl.queue_count > 1) {
                if (!ctrl->ioq_live)
                        ret = nvme_fc_create_io_queues(ctrl);
                else
                        ret = nvme_fc_recreate_io_queues(ctrl);
                if (ret)
                        goto out_term_aen_ops;
        }

        changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);

        ctrl->ctrl.nr_reconnects = 0;

        if (changed)
                nvme_start_ctrl(&ctrl->ctrl);

        return 0;       /* Success */

out_term_aen_ops:
        nvme_fc_term_aen_ops(ctrl);
out_disconnect_admin_queue:
        /* send a Disconnect(association) LS to fc-nvme target */
        nvme_fc_xmt_disconnect_assoc(ctrl);
        ctrl->association_id = 0;
out_delete_hw_queue:
        __nvme_fc_delete_hw_queue(ctrl, &ctrl->queues[0], 0);
out_free_queue:
        nvme_fc_free_queue(&ctrl->queues[0]);
        ctrl->assoc_active = false;
        nvme_fc_ctlr_inactive_on_rport(ctrl);

        return ret;
}

/*
 * This routine stops operation of the controller on the host side.
 * On the host os stack side: Admin and IO queues are stopped,
 *   outstanding ios on them terminated via FC ABTS.
 * On the link side: the association is terminated.
 */
static void
nvme_fc_delete_association(struct nvme_fc_ctrl *ctrl)
{
        unsigned long flags;

        if (!ctrl->assoc_active)
                return;
        ctrl->assoc_active = false;

        spin_lock_irqsave(&ctrl->lock, flags);
        ctrl->flags |= FCCTRL_TERMIO;
        ctrl->iocnt = 0;
        spin_unlock_irqrestore(&ctrl->lock, flags);

        /*
         * If io queues are present, stop them and terminate all outstanding
         * ios on them. As FC allocates FC exchange for each io, the
         * transport must contact the LLDD to terminate the exchange,
         * thus releasing the FC exchange. We use blk_mq_tagset_busy_itr()
         * to tell us what io's are busy and invoke a transport routine
         * to kill them with the LLDD.  After terminating the exchange
         * the LLDD will call the transport's normal io done path, but it
         * will have an aborted status. The done path will return the
         * io requests back to the block layer as part of normal completions
         * (but with error status).
         */
        if (ctrl->ctrl.queue_count > 1) {
                nvme_stop_queues(&ctrl->ctrl);
                blk_mq_tagset_busy_iter(&ctrl->tag_set,
                                nvme_fc_terminate_exchange, &ctrl->ctrl);
                blk_mq_tagset_wait_completed_request(&ctrl->tag_set);
        }

        /*
         * Other transports, which don't have link-level contexts bound
         * to sqe's, would try to gracefully shutdown the controller by
         * writing the registers for shutdown and polling (call
         * nvme_shutdown_ctrl()). Given a bunch of i/o was potentially
         * just aborted and we will wait on those contexts, and given
         * there was no indication of how live the controlelr is on the
         * link, don't send more io to create more contexts for the
         * shutdown. Let the controller fail via keepalive failure if
         * its still present.
         */

        /*
         * clean up the admin queue. Same thing as above.
         * use blk_mq_tagset_busy_itr() and the transport routine to
         * terminate the exchanges.
         */
        blk_mq_quiesce_queue(ctrl->ctrl.admin_q);
        blk_mq_tagset_busy_iter(&ctrl->admin_tag_set,
                                nvme_fc_terminate_exchange, &ctrl->ctrl);
        blk_mq_tagset_wait_completed_request(&ctrl->admin_tag_set);

        /* kill the aens as they are a separate path */
        nvme_fc_abort_aen_ops(ctrl);

        /* wait for all io that had to be aborted */
        spin_lock_irq(&ctrl->lock);
        wait_event_lock_irq(ctrl->ioabort_wait, ctrl->iocnt == 0, ctrl->lock);
        ctrl->flags &= ~FCCTRL_TERMIO;
        spin_unlock_irq(&ctrl->lock);

        nvme_fc_term_aen_ops(ctrl);

        /*
         * send a Disconnect(association) LS to fc-nvme target
         * Note: could have been sent at top of process, but
         * cleaner on link traffic if after the aborts complete.
         * Note: if association doesn't exist, association_id will be 0
         */
        if (ctrl->association_id)
                nvme_fc_xmt_disconnect_assoc(ctrl);

        ctrl->association_id = 0;

        if (ctrl->ctrl.tagset) {
                nvme_fc_delete_hw_io_queues(ctrl);
                nvme_fc_free_io_queues(ctrl);
        }

        __nvme_fc_delete_hw_queue(ctrl, &ctrl->queues[0], 0);
        nvme_fc_free_queue(&ctrl->queues[0]);

        /* re-enable the admin_q so anything new can fast fail */
        blk_mq_unquiesce_queue(ctrl->ctrl.admin_q);

        /* resume the io queues so that things will fast fail */
        nvme_start_queues(&ctrl->ctrl);

        nvme_fc_ctlr_inactive_on_rport(ctrl);
}

static void
nvme_fc_delete_ctrl(struct nvme_ctrl *nctrl)
{
        struct nvme_fc_ctrl *ctrl = to_fc_ctrl(nctrl);

        cancel_work_sync(&ctrl->err_work);
        cancel_delayed_work_sync(&ctrl->connect_work);
        /*
         * kill the association on the link side.  this will block
         * waiting for io to terminate
         */
        nvme_fc_delete_association(ctrl);
}

static void
nvme_fc_reconnect_or_delete(struct nvme_fc_ctrl *ctrl, int status)
{
        struct nvme_fc_rport *rport = ctrl->rport;
        struct nvme_fc_remote_port *portptr = &rport->remoteport;
        unsigned long recon_delay = ctrl->ctrl.opts->reconnect_delay * HZ;
        bool recon = true;

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

        if (portptr->port_state == FC_OBJSTATE_ONLINE)
                dev_info(ctrl->ctrl.device,
                        "NVME-FC{%d}: reset: Reconnect attempt failed (%d)\n",
                        ctrl->cnum, status);
        else if (time_after_eq(jiffies, rport->dev_loss_end))
                recon = false;

        if (recon && nvmf_should_reconnect(&ctrl->ctrl)) {
                if (portptr->port_state == FC_OBJSTATE_ONLINE)
                        dev_info(ctrl->ctrl.device,
                                "NVME-FC{%d}: Reconnect attempt in %ld "
                                "seconds\n",
                                ctrl->cnum, recon_delay / HZ);
                else if (time_after(jiffies + recon_delay, rport->dev_loss_end))
                        recon_delay = rport->dev_loss_end - jiffies;

                queue_delayed_work(nvme_wq, &ctrl->connect_work, recon_delay);
        } else {
                if (portptr->port_state == FC_OBJSTATE_ONLINE)
                        dev_warn(ctrl->ctrl.device,
                                "NVME-FC{%d}: Max reconnect attempts (%d) "
                                "reached.\n",
                                ctrl->cnum, ctrl->ctrl.nr_reconnects);
                else
                        dev_warn(ctrl->ctrl.device,
                                "NVME-FC{%d}: dev_loss_tmo (%d) expired "
                                "while waiting for remoteport connectivity.\n",
                                ctrl->cnum, portptr->dev_loss_tmo);
                WARN_ON(nvme_delete_ctrl(&ctrl->ctrl));
        }
}

static void
__nvme_fc_terminate_io(struct nvme_fc_ctrl *ctrl)
{
        /*
         * if state is connecting - the error occurred as part of a
         * reconnect attempt. The create_association error paths will
         * clean up any outstanding io.
         *
         * if it's a different state - ensure all pending io is
         * terminated. Given this can delay while waiting for the
         * aborted io to return, we recheck adapter state below
         * before changing state.
         */
        if (ctrl->ctrl.state != NVME_CTRL_CONNECTING) {
                nvme_stop_keep_alive(&ctrl->ctrl);

                /* will block will waiting for io to terminate */
                nvme_fc_delete_association(ctrl);
        }

        if (ctrl->ctrl.state != NVME_CTRL_CONNECTING &&
            !nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_CONNECTING))
                dev_err(ctrl->ctrl.device,
                        "NVME-FC{%d}: error_recovery: Couldn't change state "
                        "to CONNECTING\n", ctrl->cnum);
}

static void
nvme_fc_reset_ctrl_work(struct work_struct *work)
{
        struct nvme_fc_ctrl *ctrl =
                container_of(work, struct nvme_fc_ctrl, ctrl.reset_work);
        int ret;

        __nvme_fc_terminate_io(ctrl);

        nvme_stop_ctrl(&ctrl->ctrl);

        if (ctrl->rport->remoteport.port_state == FC_OBJSTATE_ONLINE)
                ret = nvme_fc_create_association(ctrl);
        else
                ret = -ENOTCONN;

        if (ret)
                nvme_fc_reconnect_or_delete(ctrl, ret);
        else
                dev_info(ctrl->ctrl.device,
                        "NVME-FC{%d}: controller reset complete\n",
                        ctrl->cnum);
}

static void
nvme_fc_connect_err_work(struct work_struct *work)
{
        struct nvme_fc_ctrl *ctrl =
                        container_of(work, struct nvme_fc_ctrl, err_work);

        __nvme_fc_terminate_io(ctrl);

        atomic_set(&ctrl->err_work_active, 0);

        /*
         * Rescheduling the connection after recovering
         * from the io error is left to the reconnect work
         * item, which is what should have stalled waiting on
         * the io that had the error that scheduled this work.
         */
}

static const struct nvme_ctrl_ops nvme_fc_ctrl_ops = {
        .name                   = "fc",
        .module                 = THIS_MODULE,
        .flags                  = NVME_F_FABRICS,
        .reg_read32             = nvmf_reg_read32,
        .reg_read64             = nvmf_reg_read64,
        .reg_write32            = nvmf_reg_write32,
        .free_ctrl              = nvme_fc_nvme_ctrl_freed,
        .submit_async_event     = nvme_fc_submit_async_event,
        .delete_ctrl            = nvme_fc_delete_ctrl,
        .get_address            = nvmf_get_address,
};

static void
nvme_fc_connect_ctrl_work(struct work_struct *work)
{
        int ret;

        struct nvme_fc_ctrl *ctrl =
                        container_of(to_delayed_work(work),
                                struct nvme_fc_ctrl, connect_work);

        ret = nvme_fc_create_association(ctrl);
        if (ret)
                nvme_fc_reconnect_or_delete(ctrl, ret);
        else
                dev_info(ctrl->ctrl.device,
                        "NVME-FC{%d}: controller connect complete\n",
                        ctrl->cnum);
}


static const struct blk_mq_ops nvme_fc_admin_mq_ops = {
        .queue_rq       = nvme_fc_queue_rq,
        .complete       = nvme_fc_complete_rq,
        .init_request   = nvme_fc_init_request,
        .exit_request   = nvme_fc_exit_request,
        .init_hctx      = nvme_fc_init_admin_hctx,
        .timeout        = nvme_fc_timeout,
};


/*
 * Fails a controller request if it matches an existing controller
 * (association) with the same tuple:
 * <Host NQN, Host ID, local FC port, remote FC port, SUBSYS NQN>
 *
 * The ports don't need to be compared as they are intrinsically
 * already matched by the port pointers supplied.
 */
static bool
nvme_fc_existing_controller(struct nvme_fc_rport *rport,
                struct nvmf_ctrl_options *opts)
{
        struct nvme_fc_ctrl *ctrl;
        unsigned long flags;
        bool found = false;

        spin_lock_irqsave(&rport->lock, flags);
        list_for_each_entry(ctrl, &rport->ctrl_list, ctrl_list) {
                found = nvmf_ctlr_matches_baseopts(&ctrl->ctrl, opts);
                if (found)
                        break;
        }
        spin_unlock_irqrestore(&rport->lock, flags);

        return found;
}

static struct nvme_ctrl *
nvme_fc_init_ctrl(struct device *dev, struct nvmf_ctrl_options *opts,
        struct nvme_fc_lport *lport, struct nvme_fc_rport *rport)
{
        struct nvme_fc_ctrl *ctrl;
        unsigned long flags;
        int ret, idx;

        if (!(rport->remoteport.port_role &
            (FC_PORT_ROLE_NVME_DISCOVERY | FC_PORT_ROLE_NVME_TARGET))) {
                ret = -EBADR;
                goto out_fail;
        }

        if (!opts->duplicate_connect &&
            nvme_fc_existing_controller(rport, opts)) {
                ret = -EALREADY;
                goto out_fail;
        }

        ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
        if (!ctrl) {
                ret = -ENOMEM;
                goto out_fail;
        }

        if (!try_module_get(lport->ops->module)) {
                ret = -EUNATCH;
                goto out_free_ctrl;
        }

        idx = ida_simple_get(&nvme_fc_ctrl_cnt, 0, 0, GFP_KERNEL);
        if (idx < 0) {
                ret = -ENOSPC;
                goto out_mod_put;
        }

        ctrl->ctrl.opts = opts;
        ctrl->ctrl.nr_reconnects = 0;
        if (lport->dev)
                ctrl->ctrl.numa_node = dev_to_node(lport->dev);
        else
                ctrl->ctrl.numa_node = NUMA_NO_NODE;
        INIT_LIST_HEAD(&ctrl->ctrl_list);
        ctrl->lport = lport;
        ctrl->rport = rport;
        ctrl->dev = lport->dev;
        ctrl->cnum = idx;
        ctrl->ioq_live = false;
        ctrl->assoc_active = false;
        atomic_set(&ctrl->err_work_active, 0);
        init_waitqueue_head(&ctrl->ioabort_wait);

        get_device(ctrl->dev);
        kref_init(&ctrl->ref);

        INIT_WORK(&ctrl->ctrl.reset_work, nvme_fc_reset_ctrl_work);
        INIT_DELAYED_WORK(&ctrl->connect_work, nvme_fc_connect_ctrl_work);
        INIT_WORK(&ctrl->err_work, nvme_fc_connect_err_work);
        spin_lock_init(&ctrl->lock);

        /* io queue count */
        ctrl->ctrl.queue_count = min_t(unsigned int,
                                opts->nr_io_queues,
                                lport->ops->max_hw_queues);
        ctrl->ctrl.queue_count++;       /* +1 for admin queue */

        ctrl->ctrl.sqsize = opts->queue_size - 1;
        ctrl->ctrl.kato = opts->kato;
        ctrl->ctrl.cntlid = 0xffff;

        ret = -ENOMEM;
        ctrl->queues = kcalloc(ctrl->ctrl.queue_count,
                                sizeof(struct nvme_fc_queue), GFP_KERNEL);
        if (!ctrl->queues)
                goto out_free_ida;

        nvme_fc_init_queue(ctrl, 0);

        memset(&ctrl->admin_tag_set, 0, sizeof(ctrl->admin_tag_set));
        ctrl->admin_tag_set.ops = &nvme_fc_admin_mq_ops;
        ctrl->admin_tag_set.queue_depth = NVME_AQ_MQ_TAG_DEPTH;
        ctrl->admin_tag_set.reserved_tags = 2; /* fabric connect + Keep-Alive */
        ctrl->admin_tag_set.numa_node = ctrl->ctrl.numa_node;
        ctrl->admin_tag_set.cmd_size =
                struct_size((struct nvme_fcp_op_w_sgl *)NULL, priv,
                            ctrl->lport->ops->fcprqst_priv_sz);
        ctrl->admin_tag_set.driver_data = ctrl;
        ctrl->admin_tag_set.nr_hw_queues = 1;
        ctrl->admin_tag_set.timeout = ADMIN_TIMEOUT;
        ctrl->admin_tag_set.flags = BLK_MQ_F_NO_SCHED;

        ret = blk_mq_alloc_tag_set(&ctrl->admin_tag_set);
        if (ret)
                goto out_free_queues;
        ctrl->ctrl.admin_tagset = &ctrl->admin_tag_set;

        ctrl->ctrl.fabrics_q = blk_mq_init_queue(&ctrl->admin_tag_set);
        if (IS_ERR(ctrl->ctrl.fabrics_q)) {
                ret = PTR_ERR(ctrl->ctrl.fabrics_q);
                goto out_free_admin_tag_set;
        }

        ctrl->ctrl.admin_q = blk_mq_init_queue(&ctrl->admin_tag_set);
        if (IS_ERR(ctrl->ctrl.admin_q)) {
                ret = PTR_ERR(ctrl->ctrl.admin_q);
                goto out_cleanup_fabrics_q;
        }

        /*
         * Would have been nice to init io queues tag set as well.
         * However, we require interaction from the controller
         * for max io queue count before we can do so.
         * Defer this to the connect path.
         */

        ret = nvme_init_ctrl(&ctrl->ctrl, dev, &nvme_fc_ctrl_ops, 0);
        if (ret)
                goto out_cleanup_admin_q;

        /* at this point, teardown path changes to ref counting on nvme ctrl */

        spin_lock_irqsave(&rport->lock, flags);
        list_add_tail(&ctrl->ctrl_list, &rport->ctrl_list);
        spin_unlock_irqrestore(&rport->lock, flags);

        if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_RESETTING) ||
            !nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_CONNECTING)) {
                dev_err(ctrl->ctrl.device,
                        "NVME-FC{%d}: failed to init ctrl state\n", ctrl->cnum);
                goto fail_ctrl;
        }

        nvme_get_ctrl(&ctrl->ctrl);

        if (!queue_delayed_work(nvme_wq, &ctrl->connect_work, 0)) {
                nvme_put_ctrl(&ctrl->ctrl);
                dev_err(ctrl->ctrl.device,
                        "NVME-FC{%d}: failed to schedule initial connect\n",
                        ctrl->cnum);
                goto fail_ctrl;
        }

        flush_delayed_work(&ctrl->connect_work);

        dev_info(ctrl->ctrl.device,
                "NVME-FC{%d}: new ctrl: NQN \"%s\"\n",
                ctrl->cnum, ctrl->ctrl.opts->subsysnqn);

        return &ctrl->ctrl;

fail_ctrl:
        nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_DELETING);
        cancel_work_sync(&ctrl->ctrl.reset_work);
        cancel_work_sync(&ctrl->err_work);
        cancel_delayed_work_sync(&ctrl->connect_work);

        ctrl->ctrl.opts = NULL;

        /* initiate nvme ctrl ref counting teardown */
        nvme_uninit_ctrl(&ctrl->ctrl);

        /* Remove core ctrl ref. */
        nvme_put_ctrl(&ctrl->ctrl);

        /* as we're past the point where we transition to the ref
         * counting teardown path, if we return a bad pointer here,
         * the calling routine, thinking it's prior to the
         * transition, will do an rport put. Since the teardown
         * path also does a rport put, we do an extra get here to
         * so proper order/teardown happens.
         */
        nvme_fc_rport_get(rport);

        return ERR_PTR(-EIO);

out_cleanup_admin_q:
        blk_cleanup_queue(ctrl->ctrl.admin_q);
out_cleanup_fabrics_q:
        blk_cleanup_queue(ctrl->ctrl.fabrics_q);
out_free_admin_tag_set:
        blk_mq_free_tag_set(&ctrl->admin_tag_set);
out_free_queues:
        kfree(ctrl->queues);
out_free_ida:
        put_device(ctrl->dev);
        ida_simple_remove(&nvme_fc_ctrl_cnt, ctrl->cnum);
out_mod_put:
        module_put(lport->ops->module);
out_free_ctrl:
        kfree(ctrl);
out_fail:
        /* exit via here doesn't follow ctlr ref points */
        return ERR_PTR(ret);
}


struct nvmet_fc_traddr {
        u64     nn;
        u64     pn;
};

static int
__nvme_fc_parse_u64(substring_t *sstr, u64 *val)
{
        u64 token64;

        if (match_u64(sstr, &token64))
                return -EINVAL;
        *val = token64;

        return 0;
}

/*
 * This routine validates and extracts the WWN's from the TRADDR string.
 * As kernel parsers need the 0x to determine number base, universally
 * build string to parse with 0x prefix before parsing name strings.
 */
static int
nvme_fc_parse_traddr(struct nvmet_fc_traddr *traddr, char *buf, size_t blen)
{
        char name[2 + NVME_FC_TRADDR_HEXNAMELEN + 1];
        substring_t wwn = { name, &name[sizeof(name)-1] };
        int nnoffset, pnoffset;

        /* validate if string is one of the 2 allowed formats */
        if (strnlen(buf, blen) == NVME_FC_TRADDR_MAXLENGTH &&
                        !strncmp(buf, "nn-0x", NVME_FC_TRADDR_OXNNLEN) &&
                        !strncmp(&buf[NVME_FC_TRADDR_MAX_PN_OFFSET],
                                "pn-0x", NVME_FC_TRADDR_OXNNLEN)) {
                nnoffset = NVME_FC_TRADDR_OXNNLEN;
                pnoffset = NVME_FC_TRADDR_MAX_PN_OFFSET +
                                                NVME_FC_TRADDR_OXNNLEN;
        } else if ((strnlen(buf, blen) == NVME_FC_TRADDR_MINLENGTH &&
                        !strncmp(buf, "nn-", NVME_FC_TRADDR_NNLEN) &&
                        !strncmp(&buf[NVME_FC_TRADDR_MIN_PN_OFFSET],
                                "pn-", NVME_FC_TRADDR_NNLEN))) {
                nnoffset = NVME_FC_TRADDR_NNLEN;
                pnoffset = NVME_FC_TRADDR_MIN_PN_OFFSET + NVME_FC_TRADDR_NNLEN;
        } else
                goto out_einval;

        name[0] = '0';
        name[1] = 'x';
        name[2 + NVME_FC_TRADDR_HEXNAMELEN] = 0;

        memcpy(&name[2], &buf[nnoffset], NVME_FC_TRADDR_HEXNAMELEN);
        if (__nvme_fc_parse_u64(&wwn, &traddr->nn))
                goto out_einval;

        memcpy(&name[2], &buf[pnoffset], NVME_FC_TRADDR_HEXNAMELEN);
        if (__nvme_fc_parse_u64(&wwn, &traddr->pn))
                goto out_einval;

        return 0;

out_einval:
        pr_warn("%s: bad traddr string\n", __func__);
        return -EINVAL;
}

static struct nvme_ctrl *
nvme_fc_create_ctrl(struct device *dev, struct nvmf_ctrl_options *opts)
{
        struct nvme_fc_lport *lport;
        struct nvme_fc_rport *rport;
        struct nvme_ctrl *ctrl;
        struct nvmet_fc_traddr laddr = { 0L, 0L };
        struct nvmet_fc_traddr raddr = { 0L, 0L };
        unsigned long flags;
        int ret;

        ret = nvme_fc_parse_traddr(&raddr, opts->traddr, NVMF_TRADDR_SIZE);
        if (ret || !raddr.nn || !raddr.pn)
                return ERR_PTR(-EINVAL);

        ret = nvme_fc_parse_traddr(&laddr, opts->host_traddr, NVMF_TRADDR_SIZE);
        if (ret || !laddr.nn || !laddr.pn)
                return ERR_PTR(-EINVAL);

        /* find the host and remote ports to connect together */
        spin_lock_irqsave(&nvme_fc_lock, flags);
        list_for_each_entry(lport, &nvme_fc_lport_list, port_list) {
                if (lport->localport.node_name != laddr.nn ||
                    lport->localport.port_name != laddr.pn)
                        continue;

                list_for_each_entry(rport, &lport->endp_list, endp_list) {
                        if (rport->remoteport.node_name != raddr.nn ||
                            rport->remoteport.port_name != raddr.pn)
                                continue;

                        /* if fail to get reference fall through. Will error */
                        if (!nvme_fc_rport_get(rport))
                                break;

                        spin_unlock_irqrestore(&nvme_fc_lock, flags);

                        ctrl = nvme_fc_init_ctrl(dev, opts, lport, rport);
                        if (IS_ERR(ctrl))
                                nvme_fc_rport_put(rport);
                        return ctrl;
                }
        }
        spin_unlock_irqrestore(&nvme_fc_lock, flags);

        pr_warn("%s: %s - %s combination not found\n",
                __func__, opts->traddr, opts->host_traddr);
        return ERR_PTR(-ENOENT);
}


static struct nvmf_transport_ops nvme_fc_transport = {
        .name           = "fc",
        .module         = THIS_MODULE,
        .required_opts  = NVMF_OPT_TRADDR | NVMF_OPT_HOST_TRADDR,
        .allowed_opts   = NVMF_OPT_RECONNECT_DELAY | NVMF_OPT_CTRL_LOSS_TMO,
        .create_ctrl    = nvme_fc_create_ctrl,
};

/* Arbitrary successive failures max. With lots of subsystems could be high */
#define DISCOVERY_MAX_FAIL      20

static ssize_t nvme_fc_nvme_discovery_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        unsigned long flags;
        LIST_HEAD(local_disc_list);
        struct nvme_fc_lport *lport;
        struct nvme_fc_rport *rport;
        int failcnt = 0;

        spin_lock_irqsave(&nvme_fc_lock, flags);
restart:
        list_for_each_entry(lport, &nvme_fc_lport_list, port_list) {
                list_for_each_entry(rport, &lport->endp_list, endp_list) {
                        if (!nvme_fc_lport_get(lport))
                                continue;
                        if (!nvme_fc_rport_get(rport)) {
                                /*
                                 * This is a temporary condition. Upon restart
                                 * this rport will be gone from the list.
                                 *
                                 * Revert the lport put and retry.  Anything
                                 * added to the list already will be skipped (as
                                 * they are no longer list_empty).  Loops should
                                 * resume at rports that were not yet seen.
                                 */
                                nvme_fc_lport_put(lport);

                                if (failcnt++ < DISCOVERY_MAX_FAIL)
                                        goto restart;

                                pr_err("nvme_discovery: too many reference "
                                       "failures\n");
                                goto process_local_list;
                        }
                        if (list_empty(&rport->disc_list))
                                list_add_tail(&rport->disc_list,
                                              &local_disc_list);
                }
        }

process_local_list:
        while (!list_empty(&local_disc_list)) {
                rport = list_first_entry(&local_disc_list,
                                         struct nvme_fc_rport, disc_list);
                list_del_init(&rport->disc_list);
                spin_unlock_irqrestore(&nvme_fc_lock, flags);

                lport = rport->lport;
                /* signal discovery. Won't hurt if it repeats */
                nvme_fc_signal_discovery_scan(lport, rport);
                nvme_fc_rport_put(rport);
                nvme_fc_lport_put(lport);

                spin_lock_irqsave(&nvme_fc_lock, flags);
        }
        spin_unlock_irqrestore(&nvme_fc_lock, flags);

        return count;
}
static DEVICE_ATTR(nvme_discovery, 0200, NULL, nvme_fc_nvme_discovery_store);

static struct attribute *nvme_fc_attrs[] = {
        &dev_attr_nvme_discovery.attr,
        NULL
};

static struct attribute_group nvme_fc_attr_group = {
        .attrs = nvme_fc_attrs,
};

static const struct attribute_group *nvme_fc_attr_groups[] = {
        &nvme_fc_attr_group,
        NULL
};

static struct class fc_class = {
        .name = "fc",
        .dev_groups = nvme_fc_attr_groups,
        .owner = THIS_MODULE,
};

static int __init nvme_fc_init_module(void)
{
        int ret;

        nvme_fc_wq = alloc_workqueue("nvme_fc_wq", WQ_MEM_RECLAIM, 0);
        if (!nvme_fc_wq)
                return -ENOMEM;

        /*
         * NOTE:
         * It is expected that in the future the kernel will combine
         * the FC-isms that are currently under scsi and now being
         * added to by NVME into a new standalone FC class. The SCSI
         * and NVME protocols and their devices would be under this
         * new FC class.
         *
         * As we need something to post FC-specific udev events to,
         * specifically for nvme probe events, start by creating the
         * new device class.  When the new standalone FC class is
         * put in place, this code will move to a more generic
         * location for the class.
         */
        ret = class_register(&fc_class);
        if (ret) {
                pr_err("couldn't register class fc\n");
                goto out_destroy_wq;
        }

        /*
         * Create a device for the FC-centric udev events
         */
        fc_udev_device = device_create(&fc_class, NULL, MKDEV(0, 0), NULL,
                                "fc_udev_device");
        if (IS_ERR(fc_udev_device)) {
                pr_err("couldn't create fc_udev device!\n");
                ret = PTR_ERR(fc_udev_device);
                goto out_destroy_class;
        }

        ret = nvmf_register_transport(&nvme_fc_transport);
        if (ret)
                goto out_destroy_device;

        return 0;

out_destroy_device:
        device_destroy(&fc_class, MKDEV(0, 0));
out_destroy_class:
        class_unregister(&fc_class);
out_destroy_wq:
        destroy_workqueue(nvme_fc_wq);

        return ret;
}

static void
nvme_fc_delete_controllers(struct nvme_fc_rport *rport)
{
        struct nvme_fc_ctrl *ctrl;

        spin_lock(&rport->lock);
        list_for_each_entry(ctrl, &rport->ctrl_list, ctrl_list) {
                dev_warn(ctrl->ctrl.device,
                        "NVME-FC{%d}: transport unloading: deleting ctrl\n",
                        ctrl->cnum);
                nvme_delete_ctrl(&ctrl->ctrl);
        }
        spin_unlock(&rport->lock);
}

static void
nvme_fc_cleanup_for_unload(void)
{
        struct nvme_fc_lport *lport;
        struct nvme_fc_rport *rport;

        list_for_each_entry(lport, &nvme_fc_lport_list, port_list) {
                list_for_each_entry(rport, &lport->endp_list, endp_list) {
                        nvme_fc_delete_controllers(rport);
                }
        }
}

static void __exit nvme_fc_exit_module(void)
{
        unsigned long flags;
        bool need_cleanup = false;

        spin_lock_irqsave(&nvme_fc_lock, flags);
        nvme_fc_waiting_to_unload = true;
        if (!list_empty(&nvme_fc_lport_list)) {
                need_cleanup = true;
                nvme_fc_cleanup_for_unload();
        }
        spin_unlock_irqrestore(&nvme_fc_lock, flags);
        if (need_cleanup) {
                pr_info("%s: waiting for ctlr deletes\n", __func__);
                wait_for_completion(&nvme_fc_unload_proceed);
                pr_info("%s: ctrl deletes complete\n", __func__);
        }

        nvmf_unregister_transport(&nvme_fc_transport);

        ida_destroy(&nvme_fc_local_port_cnt);
        ida_destroy(&nvme_fc_ctrl_cnt);

        device_destroy(&fc_class, MKDEV(0, 0));
        class_unregister(&fc_class);
        destroy_workqueue(nvme_fc_wq);
}

module_init(nvme_fc_init_module);
module_exit(nvme_fc_exit_module);

MODULE_LICENSE("GPL v2");