Merge remote-tracking branch 'drm-misc/drm-misc-next-fixes' into drm-misc-fixes

[linux-2.6-microblaze.git] / drivers / nvme / target / 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/slab.h>
#include <linux/blk-mq.h>
#include <linux/parser.h>
#include <linux/random.h>
#include <uapi/scsi/fc/fc_fs.h>
#include <uapi/scsi/fc/fc_els.h>

#include "nvmet.h"
#include <linux/nvme-fc-driver.h>
#include <linux/nvme-fc.h>
#include "../host/fc.h"


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


#define NVMET_LS_CTX_COUNT              256

struct nvmet_fc_tgtport;
struct nvmet_fc_tgt_assoc;

struct nvmet_fc_ls_iod {                /* for an LS RQST RCV */
        struct nvmefc_ls_rsp            *lsrsp;
        struct nvmefc_tgt_fcp_req       *fcpreq;        /* only if RS */

        struct list_head                ls_rcv_list; /* tgtport->ls_rcv_list */

        struct nvmet_fc_tgtport         *tgtport;
        struct nvmet_fc_tgt_assoc       *assoc;
        void                            *hosthandle;

        union nvmefc_ls_requests        *rqstbuf;
        union nvmefc_ls_responses       *rspbuf;
        u16                             rqstdatalen;
        dma_addr_t                      rspdma;

        struct scatterlist              sg[2];

        struct work_struct              work;
} __aligned(sizeof(unsigned long long));

struct nvmet_fc_ls_req_op {             /* for an LS RQST XMT */
        struct nvmefc_ls_req            ls_req;

        struct nvmet_fc_tgtport         *tgtport;
        void                            *hosthandle;

        int                             ls_error;
        struct list_head                lsreq_list; /* tgtport->ls_req_list */
        bool                            req_queued;
};


/* desired maximum for a single sequence - if sg list allows it */
#define NVMET_FC_MAX_SEQ_LENGTH         (256 * 1024)

enum nvmet_fcp_datadir {
        NVMET_FCP_NODATA,
        NVMET_FCP_WRITE,
        NVMET_FCP_READ,
        NVMET_FCP_ABORTED,
};

struct nvmet_fc_fcp_iod {
        struct nvmefc_tgt_fcp_req       *fcpreq;

        struct nvme_fc_cmd_iu           cmdiubuf;
        struct nvme_fc_ersp_iu          rspiubuf;
        dma_addr_t                      rspdma;
        struct scatterlist              *next_sg;
        struct scatterlist              *data_sg;
        int                             data_sg_cnt;
        u32                             offset;
        enum nvmet_fcp_datadir          io_dir;
        bool                            active;
        bool                            abort;
        bool                            aborted;
        bool                            writedataactive;
        spinlock_t                      flock;

        struct nvmet_req                req;
        struct work_struct              defer_work;

        struct nvmet_fc_tgtport         *tgtport;
        struct nvmet_fc_tgt_queue       *queue;

        struct list_head                fcp_list;       /* tgtport->fcp_list */
};

struct nvmet_fc_tgtport {
        struct nvmet_fc_target_port     fc_target_port;

        struct list_head                tgt_list; /* nvmet_fc_target_list */
        struct device                   *dev;   /* dev for dma mapping */
        struct nvmet_fc_target_template *ops;

        struct nvmet_fc_ls_iod          *iod;
        spinlock_t                      lock;
        struct list_head                ls_rcv_list;
        struct list_head                ls_req_list;
        struct list_head                ls_busylist;
        struct list_head                assoc_list;
        struct list_head                host_list;
        struct ida                      assoc_cnt;
        struct nvmet_fc_port_entry      *pe;
        struct kref                     ref;
        u32                             max_sg_cnt;
};

struct nvmet_fc_port_entry {
        struct nvmet_fc_tgtport         *tgtport;
        struct nvmet_port               *port;
        u64                             node_name;
        u64                             port_name;
        struct list_head                pe_list;
};

struct nvmet_fc_defer_fcp_req {
        struct list_head                req_list;
        struct nvmefc_tgt_fcp_req       *fcp_req;
};

struct nvmet_fc_tgt_queue {
        bool                            ninetypercent;
        u16                             qid;
        u16                             sqsize;
        u16                             ersp_ratio;
        __le16                          sqhd;
        atomic_t                        connected;
        atomic_t                        sqtail;
        atomic_t                        zrspcnt;
        atomic_t                        rsn;
        spinlock_t                      qlock;
        struct nvmet_cq                 nvme_cq;
        struct nvmet_sq                 nvme_sq;
        struct nvmet_fc_tgt_assoc       *assoc;
        struct list_head                fod_list;
        struct list_head                pending_cmd_list;
        struct list_head                avail_defer_list;
        struct workqueue_struct         *work_q;
        struct kref                     ref;
        struct rcu_head                 rcu;
        struct nvmet_fc_fcp_iod         fod[];          /* array of fcp_iods */
} __aligned(sizeof(unsigned long long));

struct nvmet_fc_hostport {
        struct nvmet_fc_tgtport         *tgtport;
        void                            *hosthandle;
        struct list_head                host_list;
        struct kref                     ref;
        u8                              invalid;
};

struct nvmet_fc_tgt_assoc {
        u64                             association_id;
        u32                             a_id;
        atomic_t                        terminating;
        struct nvmet_fc_tgtport         *tgtport;
        struct nvmet_fc_hostport        *hostport;
        struct nvmet_fc_ls_iod          *rcv_disconn;
        struct list_head                a_list;
        struct nvmet_fc_tgt_queue __rcu *queues[NVMET_NR_QUEUES + 1];
        struct kref                     ref;
        struct work_struct              del_work;
        struct rcu_head                 rcu;
};


static inline int
nvmet_fc_iodnum(struct nvmet_fc_ls_iod *iodptr)
{
        return (iodptr - iodptr->tgtport->iod);
}

static inline int
nvmet_fc_fodnum(struct nvmet_fc_fcp_iod *fodptr)
{
        return (fodptr - fodptr->queue->fod);
}


/*
 * Association and Connection IDs:
 *
 * Association ID will have random number in upper 6 bytes and zero
 *   in lower 2 bytes
 *
 * Connection IDs will be Association ID with QID or'd in lower 2 bytes
 *
 * note: Association ID = Connection ID for queue 0
 */
#define BYTES_FOR_QID                   sizeof(u16)
#define BYTES_FOR_QID_SHIFT             (BYTES_FOR_QID * 8)
#define NVMET_FC_QUEUEID_MASK           ((u64)((1 << BYTES_FOR_QID_SHIFT) - 1))

static inline u64
nvmet_fc_makeconnid(struct nvmet_fc_tgt_assoc *assoc, u16 qid)
{
        return (assoc->association_id | qid);
}

static inline u64
nvmet_fc_getassociationid(u64 connectionid)
{
        return connectionid & ~NVMET_FC_QUEUEID_MASK;
}

static inline u16
nvmet_fc_getqueueid(u64 connectionid)
{
        return (u16)(connectionid & NVMET_FC_QUEUEID_MASK);
}

static inline struct nvmet_fc_tgtport *
targetport_to_tgtport(struct nvmet_fc_target_port *targetport)
{
        return container_of(targetport, struct nvmet_fc_tgtport,
                                 fc_target_port);
}

static inline struct nvmet_fc_fcp_iod *
nvmet_req_to_fod(struct nvmet_req *nvme_req)
{
        return container_of(nvme_req, struct nvmet_fc_fcp_iod, req);
}


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


static DEFINE_SPINLOCK(nvmet_fc_tgtlock);

static LIST_HEAD(nvmet_fc_target_list);
static DEFINE_IDA(nvmet_fc_tgtport_cnt);
static LIST_HEAD(nvmet_fc_portentry_list);


static void nvmet_fc_handle_ls_rqst_work(struct work_struct *work);
static void nvmet_fc_fcp_rqst_op_defer_work(struct work_struct *work);
static void nvmet_fc_tgt_a_put(struct nvmet_fc_tgt_assoc *assoc);
static int nvmet_fc_tgt_a_get(struct nvmet_fc_tgt_assoc *assoc);
static void nvmet_fc_tgt_q_put(struct nvmet_fc_tgt_queue *queue);
static int nvmet_fc_tgt_q_get(struct nvmet_fc_tgt_queue *queue);
static void nvmet_fc_tgtport_put(struct nvmet_fc_tgtport *tgtport);
static int nvmet_fc_tgtport_get(struct nvmet_fc_tgtport *tgtport);
static void nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
                                        struct nvmet_fc_fcp_iod *fod);
static void nvmet_fc_delete_target_assoc(struct nvmet_fc_tgt_assoc *assoc);
static void nvmet_fc_xmt_ls_rsp(struct nvmet_fc_tgtport *tgtport,
                                struct nvmet_fc_ls_iod *iod);


/* *********************** 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 XMT Handling ************************* */


static void
__nvmet_fc_finish_ls_req(struct nvmet_fc_ls_req_op *lsop)
{
        struct nvmet_fc_tgtport *tgtport = lsop->tgtport;
        struct nvmefc_ls_req *lsreq = &lsop->ls_req;
        unsigned long flags;

        spin_lock_irqsave(&tgtport->lock, flags);

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

        list_del(&lsop->lsreq_list);

        lsop->req_queued = false;

        spin_unlock_irqrestore(&tgtport->lock, flags);

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

        nvmet_fc_tgtport_put(tgtport);
}

static int
__nvmet_fc_send_ls_req(struct nvmet_fc_tgtport *tgtport,
                struct nvmet_fc_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 (!tgtport->ops->ls_req)
                return -EOPNOTSUPP;

        if (!nvmet_fc_tgtport_get(tgtport))
                return -ESHUTDOWN;

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

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

        spin_lock_irqsave(&tgtport->lock, flags);

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

        lsop->req_queued = true;

        spin_unlock_irqrestore(&tgtport->lock, flags);

        ret = tgtport->ops->ls_req(&tgtport->fc_target_port, lsop->hosthandle,
                                   lsreq);
        if (ret)
                goto out_unlink;

        return 0;

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

        return ret;
}

static int
nvmet_fc_send_ls_req_async(struct nvmet_fc_tgtport *tgtport,
                struct nvmet_fc_ls_req_op *lsop,
                void (*done)(struct nvmefc_ls_req *req, int status))
{
        /* don't wait for completion */

        return __nvmet_fc_send_ls_req(tgtport, lsop, done);
}

static void
nvmet_fc_disconnect_assoc_done(struct nvmefc_ls_req *lsreq, int status)
{
        struct nvmet_fc_ls_req_op *lsop =
                container_of(lsreq, struct nvmet_fc_ls_req_op, ls_req);

        __nvmet_fc_finish_ls_req(lsop);

        /* fc-nvme target 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 target 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 host, so the target may never get a
 * response even if it 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 host
 * is present and receives the LS, it too can tear down.
 */
static void
nvmet_fc_xmt_disconnect_assoc(struct nvmet_fc_tgt_assoc *assoc)
{
        struct nvmet_fc_tgtport *tgtport = assoc->tgtport;
        struct fcnvme_ls_disconnect_assoc_rqst *discon_rqst;
        struct fcnvme_ls_disconnect_assoc_acc *discon_acc;
        struct nvmet_fc_ls_req_op *lsop;
        struct nvmefc_ls_req *lsreq;
        int ret;

        /*
         * If ls_req is NULL or no hosthandle, it's an older lldd and no
         * message is normal. Otherwise, send unless the hostport has
         * already been invalidated by the lldd.
         */
        if (!tgtport->ops->ls_req || !assoc->hostport ||
            assoc->hostport->invalid)
                return;

        lsop = kzalloc((sizeof(*lsop) +
                        sizeof(*discon_rqst) + sizeof(*discon_acc) +
                        tgtport->ops->lsrqst_priv_sz), GFP_KERNEL);
        if (!lsop) {
                dev_info(tgtport->dev,
                        "{%d:%d} send Disconnect Association failed: ENOMEM\n",
                        tgtport->fc_target_port.port_num, assoc->a_id);
                return;
        }

        discon_rqst = (struct fcnvme_ls_disconnect_assoc_rqst *)&lsop[1];
        discon_acc = (struct fcnvme_ls_disconnect_assoc_acc *)&discon_rqst[1];
        lsreq = &lsop->ls_req;
        if (tgtport->ops->lsrqst_priv_sz)
                lsreq->private = (void *)&discon_acc[1];
        else
                lsreq->private = NULL;

        lsop->tgtport = tgtport;
        lsop->hosthandle = assoc->hostport->hosthandle;

        nvmefc_fmt_lsreq_discon_assoc(lsreq, discon_rqst, discon_acc,
                                assoc->association_id);

        ret = nvmet_fc_send_ls_req_async(tgtport, lsop,
                                nvmet_fc_disconnect_assoc_done);
        if (ret) {
                dev_info(tgtport->dev,
                        "{%d:%d} XMT Disconnect Association failed: %d\n",
                        tgtport->fc_target_port.port_num, assoc->a_id, ret);
                kfree(lsop);
        }
}


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


static int
nvmet_fc_alloc_ls_iodlist(struct nvmet_fc_tgtport *tgtport)
{
        struct nvmet_fc_ls_iod *iod;
        int i;

        iod = kcalloc(NVMET_LS_CTX_COUNT, sizeof(struct nvmet_fc_ls_iod),
                        GFP_KERNEL);
        if (!iod)
                return -ENOMEM;

        tgtport->iod = iod;

        for (i = 0; i < NVMET_LS_CTX_COUNT; iod++, i++) {
                INIT_WORK(&iod->work, nvmet_fc_handle_ls_rqst_work);
                iod->tgtport = tgtport;
                list_add_tail(&iod->ls_rcv_list, &tgtport->ls_rcv_list);

                iod->rqstbuf = kzalloc(sizeof(union nvmefc_ls_requests) +
                                       sizeof(union nvmefc_ls_responses),
                                       GFP_KERNEL);
                if (!iod->rqstbuf)
                        goto out_fail;

                iod->rspbuf = (union nvmefc_ls_responses *)&iod->rqstbuf[1];

                iod->rspdma = fc_dma_map_single(tgtport->dev, iod->rspbuf,
                                                sizeof(*iod->rspbuf),
                                                DMA_TO_DEVICE);
                if (fc_dma_mapping_error(tgtport->dev, iod->rspdma))
                        goto out_fail;
        }

        return 0;

out_fail:
        kfree(iod->rqstbuf);
        list_del(&iod->ls_rcv_list);
        for (iod--, i--; i >= 0; iod--, i--) {
                fc_dma_unmap_single(tgtport->dev, iod->rspdma,
                                sizeof(*iod->rspbuf), DMA_TO_DEVICE);
                kfree(iod->rqstbuf);
                list_del(&iod->ls_rcv_list);
        }

        kfree(iod);

        return -EFAULT;
}

static void
nvmet_fc_free_ls_iodlist(struct nvmet_fc_tgtport *tgtport)
{
        struct nvmet_fc_ls_iod *iod = tgtport->iod;
        int i;

        for (i = 0; i < NVMET_LS_CTX_COUNT; iod++, i++) {
                fc_dma_unmap_single(tgtport->dev,
                                iod->rspdma, sizeof(*iod->rspbuf),
                                DMA_TO_DEVICE);
                kfree(iod->rqstbuf);
                list_del(&iod->ls_rcv_list);
        }
        kfree(tgtport->iod);
}

static struct nvmet_fc_ls_iod *
nvmet_fc_alloc_ls_iod(struct nvmet_fc_tgtport *tgtport)
{
        struct nvmet_fc_ls_iod *iod;
        unsigned long flags;

        spin_lock_irqsave(&tgtport->lock, flags);
        iod = list_first_entry_or_null(&tgtport->ls_rcv_list,
                                        struct nvmet_fc_ls_iod, ls_rcv_list);
        if (iod)
                list_move_tail(&iod->ls_rcv_list, &tgtport->ls_busylist);
        spin_unlock_irqrestore(&tgtport->lock, flags);
        return iod;
}


static void
nvmet_fc_free_ls_iod(struct nvmet_fc_tgtport *tgtport,
                        struct nvmet_fc_ls_iod *iod)
{
        unsigned long flags;

        spin_lock_irqsave(&tgtport->lock, flags);
        list_move(&iod->ls_rcv_list, &tgtport->ls_rcv_list);
        spin_unlock_irqrestore(&tgtport->lock, flags);
}

static void
nvmet_fc_prep_fcp_iodlist(struct nvmet_fc_tgtport *tgtport,
                                struct nvmet_fc_tgt_queue *queue)
{
        struct nvmet_fc_fcp_iod *fod = queue->fod;
        int i;

        for (i = 0; i < queue->sqsize; fod++, i++) {
                INIT_WORK(&fod->defer_work, nvmet_fc_fcp_rqst_op_defer_work);
                fod->tgtport = tgtport;
                fod->queue = queue;
                fod->active = false;
                fod->abort = false;
                fod->aborted = false;
                fod->fcpreq = NULL;
                list_add_tail(&fod->fcp_list, &queue->fod_list);
                spin_lock_init(&fod->flock);

                fod->rspdma = fc_dma_map_single(tgtport->dev, &fod->rspiubuf,
                                        sizeof(fod->rspiubuf), DMA_TO_DEVICE);
                if (fc_dma_mapping_error(tgtport->dev, fod->rspdma)) {
                        list_del(&fod->fcp_list);
                        for (fod--, i--; i >= 0; fod--, i--) {
                                fc_dma_unmap_single(tgtport->dev, fod->rspdma,
                                                sizeof(fod->rspiubuf),
                                                DMA_TO_DEVICE);
                                fod->rspdma = 0L;
                                list_del(&fod->fcp_list);
                        }

                        return;
                }
        }
}

static void
nvmet_fc_destroy_fcp_iodlist(struct nvmet_fc_tgtport *tgtport,
                                struct nvmet_fc_tgt_queue *queue)
{
        struct nvmet_fc_fcp_iod *fod = queue->fod;
        int i;

        for (i = 0; i < queue->sqsize; fod++, i++) {
                if (fod->rspdma)
                        fc_dma_unmap_single(tgtport->dev, fod->rspdma,
                                sizeof(fod->rspiubuf), DMA_TO_DEVICE);
        }
}

static struct nvmet_fc_fcp_iod *
nvmet_fc_alloc_fcp_iod(struct nvmet_fc_tgt_queue *queue)
{
        struct nvmet_fc_fcp_iod *fod;

        lockdep_assert_held(&queue->qlock);

        fod = list_first_entry_or_null(&queue->fod_list,
                                        struct nvmet_fc_fcp_iod, fcp_list);
        if (fod) {
                list_del(&fod->fcp_list);
                fod->active = true;
                /*
                 * no queue reference is taken, as it was taken by the
                 * queue lookup just prior to the allocation. The iod
                 * will "inherit" that reference.
                 */
        }
        return fod;
}


static void
nvmet_fc_queue_fcp_req(struct nvmet_fc_tgtport *tgtport,
                       struct nvmet_fc_tgt_queue *queue,
                       struct nvmefc_tgt_fcp_req *fcpreq)
{
        struct nvmet_fc_fcp_iod *fod = fcpreq->nvmet_fc_private;

        /*
         * put all admin cmds on hw queue id 0. All io commands go to
         * the respective hw queue based on a modulo basis
         */
        fcpreq->hwqid = queue->qid ?
                        ((queue->qid - 1) % tgtport->ops->max_hw_queues) : 0;

        nvmet_fc_handle_fcp_rqst(tgtport, fod);
}

static void
nvmet_fc_fcp_rqst_op_defer_work(struct work_struct *work)
{
        struct nvmet_fc_fcp_iod *fod =
                container_of(work, struct nvmet_fc_fcp_iod, defer_work);

        /* Submit deferred IO for processing */
        nvmet_fc_queue_fcp_req(fod->tgtport, fod->queue, fod->fcpreq);

}

static void
nvmet_fc_free_fcp_iod(struct nvmet_fc_tgt_queue *queue,
                        struct nvmet_fc_fcp_iod *fod)
{
        struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq;
        struct nvmet_fc_tgtport *tgtport = fod->tgtport;
        struct nvmet_fc_defer_fcp_req *deferfcp;
        unsigned long flags;

        fc_dma_sync_single_for_cpu(tgtport->dev, fod->rspdma,
                                sizeof(fod->rspiubuf), DMA_TO_DEVICE);

        fcpreq->nvmet_fc_private = NULL;

        fod->active = false;
        fod->abort = false;
        fod->aborted = false;
        fod->writedataactive = false;
        fod->fcpreq = NULL;

        tgtport->ops->fcp_req_release(&tgtport->fc_target_port, fcpreq);

        /* release the queue lookup reference on the completed IO */
        nvmet_fc_tgt_q_put(queue);

        spin_lock_irqsave(&queue->qlock, flags);
        deferfcp = list_first_entry_or_null(&queue->pending_cmd_list,
                                struct nvmet_fc_defer_fcp_req, req_list);
        if (!deferfcp) {
                list_add_tail(&fod->fcp_list, &fod->queue->fod_list);
                spin_unlock_irqrestore(&queue->qlock, flags);
                return;
        }

        /* Re-use the fod for the next pending cmd that was deferred */
        list_del(&deferfcp->req_list);

        fcpreq = deferfcp->fcp_req;

        /* deferfcp can be reused for another IO at a later date */
        list_add_tail(&deferfcp->req_list, &queue->avail_defer_list);

        spin_unlock_irqrestore(&queue->qlock, flags);

        /* Save NVME CMD IO in fod */
        memcpy(&fod->cmdiubuf, fcpreq->rspaddr, fcpreq->rsplen);

        /* Setup new fcpreq to be processed */
        fcpreq->rspaddr = NULL;
        fcpreq->rsplen  = 0;
        fcpreq->nvmet_fc_private = fod;
        fod->fcpreq = fcpreq;
        fod->active = true;

        /* inform LLDD IO is now being processed */
        tgtport->ops->defer_rcv(&tgtport->fc_target_port, fcpreq);

        /*
         * Leave the queue lookup get reference taken when
         * fod was originally allocated.
         */

        queue_work(queue->work_q, &fod->defer_work);
}

static struct nvmet_fc_tgt_queue *
nvmet_fc_alloc_target_queue(struct nvmet_fc_tgt_assoc *assoc,
                        u16 qid, u16 sqsize)
{
        struct nvmet_fc_tgt_queue *queue;
        int ret;

        if (qid > NVMET_NR_QUEUES)
                return NULL;

        queue = kzalloc(struct_size(queue, fod, sqsize), GFP_KERNEL);
        if (!queue)
                return NULL;

        if (!nvmet_fc_tgt_a_get(assoc))
                goto out_free_queue;

        queue->work_q = alloc_workqueue("ntfc%d.%d.%d", 0, 0,
                                assoc->tgtport->fc_target_port.port_num,
                                assoc->a_id, qid);
        if (!queue->work_q)
                goto out_a_put;

        queue->qid = qid;
        queue->sqsize = sqsize;
        queue->assoc = assoc;
        INIT_LIST_HEAD(&queue->fod_list);
        INIT_LIST_HEAD(&queue->avail_defer_list);
        INIT_LIST_HEAD(&queue->pending_cmd_list);
        atomic_set(&queue->connected, 0);
        atomic_set(&queue->sqtail, 0);
        atomic_set(&queue->rsn, 1);
        atomic_set(&queue->zrspcnt, 0);
        spin_lock_init(&queue->qlock);
        kref_init(&queue->ref);

        nvmet_fc_prep_fcp_iodlist(assoc->tgtport, queue);

        ret = nvmet_sq_init(&queue->nvme_sq);
        if (ret)
                goto out_fail_iodlist;

        WARN_ON(assoc->queues[qid]);
        rcu_assign_pointer(assoc->queues[qid], queue);

        return queue;

out_fail_iodlist:
        nvmet_fc_destroy_fcp_iodlist(assoc->tgtport, queue);
        destroy_workqueue(queue->work_q);
out_a_put:
        nvmet_fc_tgt_a_put(assoc);
out_free_queue:
        kfree(queue);
        return NULL;
}


static void
nvmet_fc_tgt_queue_free(struct kref *ref)
{
        struct nvmet_fc_tgt_queue *queue =
                container_of(ref, struct nvmet_fc_tgt_queue, ref);

        rcu_assign_pointer(queue->assoc->queues[queue->qid], NULL);

        nvmet_fc_destroy_fcp_iodlist(queue->assoc->tgtport, queue);

        nvmet_fc_tgt_a_put(queue->assoc);

        destroy_workqueue(queue->work_q);

        kfree_rcu(queue, rcu);
}

static void
nvmet_fc_tgt_q_put(struct nvmet_fc_tgt_queue *queue)
{
        kref_put(&queue->ref, nvmet_fc_tgt_queue_free);
}

static int
nvmet_fc_tgt_q_get(struct nvmet_fc_tgt_queue *queue)
{
        return kref_get_unless_zero(&queue->ref);
}


static void
nvmet_fc_delete_target_queue(struct nvmet_fc_tgt_queue *queue)
{
        struct nvmet_fc_tgtport *tgtport = queue->assoc->tgtport;
        struct nvmet_fc_fcp_iod *fod = queue->fod;
        struct nvmet_fc_defer_fcp_req *deferfcp, *tempptr;
        unsigned long flags;
        int i;
        bool disconnect;

        disconnect = atomic_xchg(&queue->connected, 0);

        /* if not connected, nothing to do */
        if (!disconnect)
                return;

        spin_lock_irqsave(&queue->qlock, flags);
        /* abort outstanding io's */
        for (i = 0; i < queue->sqsize; fod++, i++) {
                if (fod->active) {
                        spin_lock(&fod->flock);
                        fod->abort = true;
                        /*
                         * only call lldd abort routine if waiting for
                         * writedata. other outstanding ops should finish
                         * on their own.
                         */
                        if (fod->writedataactive) {
                                fod->aborted = true;
                                spin_unlock(&fod->flock);
                                tgtport->ops->fcp_abort(
                                        &tgtport->fc_target_port, fod->fcpreq);
                        } else
                                spin_unlock(&fod->flock);
                }
        }

        /* Cleanup defer'ed IOs in queue */
        list_for_each_entry_safe(deferfcp, tempptr, &queue->avail_defer_list,
                                req_list) {
                list_del(&deferfcp->req_list);
                kfree(deferfcp);
        }

        for (;;) {
                deferfcp = list_first_entry_or_null(&queue->pending_cmd_list,
                                struct nvmet_fc_defer_fcp_req, req_list);
                if (!deferfcp)
                        break;

                list_del(&deferfcp->req_list);
                spin_unlock_irqrestore(&queue->qlock, flags);

                tgtport->ops->defer_rcv(&tgtport->fc_target_port,
                                deferfcp->fcp_req);

                tgtport->ops->fcp_abort(&tgtport->fc_target_port,
                                deferfcp->fcp_req);

                tgtport->ops->fcp_req_release(&tgtport->fc_target_port,
                                deferfcp->fcp_req);

                /* release the queue lookup reference */
                nvmet_fc_tgt_q_put(queue);

                kfree(deferfcp);

                spin_lock_irqsave(&queue->qlock, flags);
        }
        spin_unlock_irqrestore(&queue->qlock, flags);

        flush_workqueue(queue->work_q);

        nvmet_sq_destroy(&queue->nvme_sq);

        nvmet_fc_tgt_q_put(queue);
}

static struct nvmet_fc_tgt_queue *
nvmet_fc_find_target_queue(struct nvmet_fc_tgtport *tgtport,
                                u64 connection_id)
{
        struct nvmet_fc_tgt_assoc *assoc;
        struct nvmet_fc_tgt_queue *queue;
        u64 association_id = nvmet_fc_getassociationid(connection_id);
        u16 qid = nvmet_fc_getqueueid(connection_id);

        if (qid > NVMET_NR_QUEUES)
                return NULL;

        rcu_read_lock();
        list_for_each_entry_rcu(assoc, &tgtport->assoc_list, a_list) {
                if (association_id == assoc->association_id) {
                        queue = rcu_dereference(assoc->queues[qid]);
                        if (queue &&
                            (!atomic_read(&queue->connected) ||
                             !nvmet_fc_tgt_q_get(queue)))
                                queue = NULL;
                        rcu_read_unlock();
                        return queue;
                }
        }
        rcu_read_unlock();
        return NULL;
}

static void
nvmet_fc_hostport_free(struct kref *ref)
{
        struct nvmet_fc_hostport *hostport =
                container_of(ref, struct nvmet_fc_hostport, ref);
        struct nvmet_fc_tgtport *tgtport = hostport->tgtport;
        unsigned long flags;

        spin_lock_irqsave(&tgtport->lock, flags);
        list_del(&hostport->host_list);
        spin_unlock_irqrestore(&tgtport->lock, flags);
        if (tgtport->ops->host_release && hostport->invalid)
                tgtport->ops->host_release(hostport->hosthandle);
        kfree(hostport);
        nvmet_fc_tgtport_put(tgtport);
}

static void
nvmet_fc_hostport_put(struct nvmet_fc_hostport *hostport)
{
        kref_put(&hostport->ref, nvmet_fc_hostport_free);
}

static int
nvmet_fc_hostport_get(struct nvmet_fc_hostport *hostport)
{
        return kref_get_unless_zero(&hostport->ref);
}

static void
nvmet_fc_free_hostport(struct nvmet_fc_hostport *hostport)
{
        /* if LLDD not implemented, leave as NULL */
        if (!hostport || !hostport->hosthandle)
                return;

        nvmet_fc_hostport_put(hostport);
}

static struct nvmet_fc_hostport *
nvmet_fc_match_hostport(struct nvmet_fc_tgtport *tgtport, void *hosthandle)
{
        struct nvmet_fc_hostport *host;

        lockdep_assert_held(&tgtport->lock);

        list_for_each_entry(host, &tgtport->host_list, host_list) {
                if (host->hosthandle == hosthandle && !host->invalid) {
                        if (nvmet_fc_hostport_get(host))
                                return (host);
                }
        }

        return NULL;
}

static struct nvmet_fc_hostport *
nvmet_fc_alloc_hostport(struct nvmet_fc_tgtport *tgtport, void *hosthandle)
{
        struct nvmet_fc_hostport *newhost, *match = NULL;
        unsigned long flags;

        /* if LLDD not implemented, leave as NULL */
        if (!hosthandle)
                return NULL;

        /*
         * take reference for what will be the newly allocated hostport if
         * we end up using a new allocation
         */
        if (!nvmet_fc_tgtport_get(tgtport))
                return ERR_PTR(-EINVAL);

        spin_lock_irqsave(&tgtport->lock, flags);
        match = nvmet_fc_match_hostport(tgtport, hosthandle);
        spin_unlock_irqrestore(&tgtport->lock, flags);

        if (match) {
                /* no new allocation - release reference */
                nvmet_fc_tgtport_put(tgtport);
                return match;
        }

        newhost = kzalloc(sizeof(*newhost), GFP_KERNEL);
        if (!newhost) {
                /* no new allocation - release reference */
                nvmet_fc_tgtport_put(tgtport);
                return ERR_PTR(-ENOMEM);
        }

        spin_lock_irqsave(&tgtport->lock, flags);
        match = nvmet_fc_match_hostport(tgtport, hosthandle);
        if (match) {
                /* new allocation not needed */
                kfree(newhost);
                newhost = match;
                /* no new allocation - release reference */
                nvmet_fc_tgtport_put(tgtport);
        } else {
                newhost->tgtport = tgtport;
                newhost->hosthandle = hosthandle;
                INIT_LIST_HEAD(&newhost->host_list);
                kref_init(&newhost->ref);

                list_add_tail(&newhost->host_list, &tgtport->host_list);
        }
        spin_unlock_irqrestore(&tgtport->lock, flags);

        return newhost;
}

static void
nvmet_fc_delete_assoc(struct work_struct *work)
{
        struct nvmet_fc_tgt_assoc *assoc =
                container_of(work, struct nvmet_fc_tgt_assoc, del_work);

        nvmet_fc_delete_target_assoc(assoc);
        nvmet_fc_tgt_a_put(assoc);
}

static struct nvmet_fc_tgt_assoc *
nvmet_fc_alloc_target_assoc(struct nvmet_fc_tgtport *tgtport, void *hosthandle)
{
        struct nvmet_fc_tgt_assoc *assoc, *tmpassoc;
        unsigned long flags;
        u64 ran;
        int idx;
        bool needrandom = true;

        assoc = kzalloc(sizeof(*assoc), GFP_KERNEL);
        if (!assoc)
                return NULL;

        idx = ida_simple_get(&tgtport->assoc_cnt, 0, 0, GFP_KERNEL);
        if (idx < 0)
                goto out_free_assoc;

        if (!nvmet_fc_tgtport_get(tgtport))
                goto out_ida;

        assoc->hostport = nvmet_fc_alloc_hostport(tgtport, hosthandle);
        if (IS_ERR(assoc->hostport))
                goto out_put;

        assoc->tgtport = tgtport;
        assoc->a_id = idx;
        INIT_LIST_HEAD(&assoc->a_list);
        kref_init(&assoc->ref);
        INIT_WORK(&assoc->del_work, nvmet_fc_delete_assoc);
        atomic_set(&assoc->terminating, 0);

        while (needrandom) {
                get_random_bytes(&ran, sizeof(ran) - BYTES_FOR_QID);
                ran = ran << BYTES_FOR_QID_SHIFT;

                spin_lock_irqsave(&tgtport->lock, flags);
                needrandom = false;
                list_for_each_entry(tmpassoc, &tgtport->assoc_list, a_list) {
                        if (ran == tmpassoc->association_id) {
                                needrandom = true;
                                break;
                        }
                }
                if (!needrandom) {
                        assoc->association_id = ran;
                        list_add_tail_rcu(&assoc->a_list, &tgtport->assoc_list);
                }
                spin_unlock_irqrestore(&tgtport->lock, flags);
        }

        return assoc;

out_put:
        nvmet_fc_tgtport_put(tgtport);
out_ida:
        ida_simple_remove(&tgtport->assoc_cnt, idx);
out_free_assoc:
        kfree(assoc);
        return NULL;
}

static void
nvmet_fc_target_assoc_free(struct kref *ref)
{
        struct nvmet_fc_tgt_assoc *assoc =
                container_of(ref, struct nvmet_fc_tgt_assoc, ref);
        struct nvmet_fc_tgtport *tgtport = assoc->tgtport;
        struct nvmet_fc_ls_iod  *oldls;
        unsigned long flags;

        /* Send Disconnect now that all i/o has completed */
        nvmet_fc_xmt_disconnect_assoc(assoc);

        nvmet_fc_free_hostport(assoc->hostport);
        spin_lock_irqsave(&tgtport->lock, flags);
        list_del_rcu(&assoc->a_list);
        oldls = assoc->rcv_disconn;
        spin_unlock_irqrestore(&tgtport->lock, flags);
        /* if pending Rcv Disconnect Association LS, send rsp now */
        if (oldls)
                nvmet_fc_xmt_ls_rsp(tgtport, oldls);
        ida_simple_remove(&tgtport->assoc_cnt, assoc->a_id);
        dev_info(tgtport->dev,
                "{%d:%d} Association freed\n",
                tgtport->fc_target_port.port_num, assoc->a_id);
        kfree_rcu(assoc, rcu);
        nvmet_fc_tgtport_put(tgtport);
}

static void
nvmet_fc_tgt_a_put(struct nvmet_fc_tgt_assoc *assoc)
{
        kref_put(&assoc->ref, nvmet_fc_target_assoc_free);
}

static int
nvmet_fc_tgt_a_get(struct nvmet_fc_tgt_assoc *assoc)
{
        return kref_get_unless_zero(&assoc->ref);
}

static void
nvmet_fc_delete_target_assoc(struct nvmet_fc_tgt_assoc *assoc)
{
        struct nvmet_fc_tgtport *tgtport = assoc->tgtport;
        struct nvmet_fc_tgt_queue *queue;
        int i, terminating;

        terminating = atomic_xchg(&assoc->terminating, 1);

        /* if already terminating, do nothing */
        if (terminating)
                return;


        for (i = NVMET_NR_QUEUES; i >= 0; i--) {
                rcu_read_lock();
                queue = rcu_dereference(assoc->queues[i]);
                if (!queue) {
                        rcu_read_unlock();
                        continue;
                }

                if (!nvmet_fc_tgt_q_get(queue)) {
                        rcu_read_unlock();
                        continue;
                }
                rcu_read_unlock();
                nvmet_fc_delete_target_queue(queue);
                nvmet_fc_tgt_q_put(queue);
        }

        dev_info(tgtport->dev,
                "{%d:%d} Association deleted\n",
                tgtport->fc_target_port.port_num, assoc->a_id);

        nvmet_fc_tgt_a_put(assoc);
}

static struct nvmet_fc_tgt_assoc *
nvmet_fc_find_target_assoc(struct nvmet_fc_tgtport *tgtport,
                                u64 association_id)
{
        struct nvmet_fc_tgt_assoc *assoc;
        struct nvmet_fc_tgt_assoc *ret = NULL;

        rcu_read_lock();
        list_for_each_entry_rcu(assoc, &tgtport->assoc_list, a_list) {
                if (association_id == assoc->association_id) {
                        ret = assoc;
                        if (!nvmet_fc_tgt_a_get(assoc))
                                ret = NULL;
                        break;
                }
        }
        rcu_read_unlock();

        return ret;
}

static void
nvmet_fc_portentry_bind(struct nvmet_fc_tgtport *tgtport,
                        struct nvmet_fc_port_entry *pe,
                        struct nvmet_port *port)
{
        lockdep_assert_held(&nvmet_fc_tgtlock);

        pe->tgtport = tgtport;
        tgtport->pe = pe;

        pe->port = port;
        port->priv = pe;

        pe->node_name = tgtport->fc_target_port.node_name;
        pe->port_name = tgtport->fc_target_port.port_name;
        INIT_LIST_HEAD(&pe->pe_list);

        list_add_tail(&pe->pe_list, &nvmet_fc_portentry_list);
}

static void
nvmet_fc_portentry_unbind(struct nvmet_fc_port_entry *pe)
{
        unsigned long flags;

        spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
        if (pe->tgtport)
                pe->tgtport->pe = NULL;
        list_del(&pe->pe_list);
        spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
}

/*
 * called when a targetport deregisters. Breaks the relationship
 * with the nvmet port, but leaves the port_entry in place so that
 * re-registration can resume operation.
 */
static void
nvmet_fc_portentry_unbind_tgt(struct nvmet_fc_tgtport *tgtport)
{
        struct nvmet_fc_port_entry *pe;
        unsigned long flags;

        spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
        pe = tgtport->pe;
        if (pe)
                pe->tgtport = NULL;
        tgtport->pe = NULL;
        spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
}

/*
 * called when a new targetport is registered. Looks in the
 * existing nvmet port_entries to see if the nvmet layer is
 * configured for the targetport's wwn's. (the targetport existed,
 * nvmet configured, the lldd unregistered the tgtport, and is now
 * reregistering the same targetport).  If so, set the nvmet port
 * port entry on the targetport.
 */
static void
nvmet_fc_portentry_rebind_tgt(struct nvmet_fc_tgtport *tgtport)
{
        struct nvmet_fc_port_entry *pe;
        unsigned long flags;

        spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
        list_for_each_entry(pe, &nvmet_fc_portentry_list, pe_list) {
                if (tgtport->fc_target_port.node_name == pe->node_name &&
                    tgtport->fc_target_port.port_name == pe->port_name) {
                        WARN_ON(pe->tgtport);
                        tgtport->pe = pe;
                        pe->tgtport = tgtport;
                        break;
                }
        }
        spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
}

/**
 * nvme_fc_register_targetport - transport entry point called by an
 *                              LLDD to register the existence of a local
 *                              NVME subystem 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 NULL.
 *
 * Returns:
 * a completion status. Must be 0 upon success; a negative errno
 * (ex: -ENXIO) upon failure.
 */
int
nvmet_fc_register_targetport(struct nvmet_fc_port_info *pinfo,
                        struct nvmet_fc_target_template *template,
                        struct device *dev,
                        struct nvmet_fc_target_port **portptr)
{
        struct nvmet_fc_tgtport *newrec;
        unsigned long flags;
        int ret, idx;

        if (!template->xmt_ls_rsp || !template->fcp_op ||
            !template->fcp_abort ||
            !template->fcp_req_release || !template->targetport_delete ||
            !template->max_hw_queues || !template->max_sgl_segments ||
            !template->max_dif_sgl_segments || !template->dma_boundary) {
                ret = -EINVAL;
                goto out_regtgt_failed;
        }

        newrec = kzalloc((sizeof(*newrec) + template->target_priv_sz),
                         GFP_KERNEL);
        if (!newrec) {
                ret = -ENOMEM;
                goto out_regtgt_failed;
        }

        idx = ida_simple_get(&nvmet_fc_tgtport_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;
        }

        newrec->fc_target_port.node_name = pinfo->node_name;
        newrec->fc_target_port.port_name = pinfo->port_name;
        if (template->target_priv_sz)
                newrec->fc_target_port.private = &newrec[1];
        else
                newrec->fc_target_port.private = NULL;
        newrec->fc_target_port.port_id = pinfo->port_id;
        newrec->fc_target_port.port_num = idx;
        INIT_LIST_HEAD(&newrec->tgt_list);
        newrec->dev = dev;
        newrec->ops = template;
        spin_lock_init(&newrec->lock);
        INIT_LIST_HEAD(&newrec->ls_rcv_list);
        INIT_LIST_HEAD(&newrec->ls_req_list);
        INIT_LIST_HEAD(&newrec->ls_busylist);
        INIT_LIST_HEAD(&newrec->assoc_list);
        INIT_LIST_HEAD(&newrec->host_list);
        kref_init(&newrec->ref);
        ida_init(&newrec->assoc_cnt);
        newrec->max_sg_cnt = template->max_sgl_segments;

        ret = nvmet_fc_alloc_ls_iodlist(newrec);
        if (ret) {
                ret = -ENOMEM;
                goto out_free_newrec;
        }

        nvmet_fc_portentry_rebind_tgt(newrec);

        spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
        list_add_tail(&newrec->tgt_list, &nvmet_fc_target_list);
        spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);

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

out_free_newrec:
        put_device(dev);
out_ida_put:
        ida_simple_remove(&nvmet_fc_tgtport_cnt, idx);
out_fail_kfree:
        kfree(newrec);
out_regtgt_failed:
        *portptr = NULL;
        return ret;
}
EXPORT_SYMBOL_GPL(nvmet_fc_register_targetport);


static void
nvmet_fc_free_tgtport(struct kref *ref)
{
        struct nvmet_fc_tgtport *tgtport =
                container_of(ref, struct nvmet_fc_tgtport, ref);
        struct device *dev = tgtport->dev;
        unsigned long flags;

        spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
        list_del(&tgtport->tgt_list);
        spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);

        nvmet_fc_free_ls_iodlist(tgtport);

        /* let the LLDD know we've finished tearing it down */
        tgtport->ops->targetport_delete(&tgtport->fc_target_port);

        ida_simple_remove(&nvmet_fc_tgtport_cnt,
                        tgtport->fc_target_port.port_num);

        ida_destroy(&tgtport->assoc_cnt);

        kfree(tgtport);

        put_device(dev);
}

static void
nvmet_fc_tgtport_put(struct nvmet_fc_tgtport *tgtport)
{
        kref_put(&tgtport->ref, nvmet_fc_free_tgtport);
}

static int
nvmet_fc_tgtport_get(struct nvmet_fc_tgtport *tgtport)
{
        return kref_get_unless_zero(&tgtport->ref);
}

static void
__nvmet_fc_free_assocs(struct nvmet_fc_tgtport *tgtport)
{
        struct nvmet_fc_tgt_assoc *assoc;

        rcu_read_lock();
        list_for_each_entry_rcu(assoc, &tgtport->assoc_list, a_list) {
                if (!nvmet_fc_tgt_a_get(assoc))
                        continue;
                if (!schedule_work(&assoc->del_work))
                        /* already deleting - release local reference */
                        nvmet_fc_tgt_a_put(assoc);
        }
        rcu_read_unlock();
}

/**
 * nvmet_fc_invalidate_host - transport entry point called by an LLDD
 *                       to remove references to a hosthandle for LS's.
 *
 * The nvmet-fc layer ensures that any references to the hosthandle
 * on the targetport are forgotten (set to NULL).  The LLDD will
 * typically call this when a login with a remote host port has been
 * lost, thus LS's for the remote host port are no longer possible.
 *
 * If an LS request is outstanding to the targetport/hosthandle (or
 * issued concurrently with the call to invalidate the host), the
 * LLDD is responsible for terminating/aborting the LS and completing
 * the LS request. It is recommended that these terminations/aborts
 * occur after calling to invalidate the host handle to avoid additional
 * retries by the nvmet-fc transport. The nvmet-fc transport may
 * continue to reference host handle while it cleans up outstanding
 * NVME associations. The nvmet-fc transport will call the
 * ops->host_release() callback to notify the LLDD that all references
 * are complete and the related host handle can be recovered.
 * Note: if there are no references, the callback may be called before
 * the invalidate host call returns.
 *
 * @target_port: pointer to the (registered) target port that a prior
 *              LS was received on and which supplied the transport the
 *              hosthandle.
 * @hosthandle: the handle (pointer) that represents the host port
 *              that no longer has connectivity and that LS's should
 *              no longer be directed to.
 */
void
nvmet_fc_invalidate_host(struct nvmet_fc_target_port *target_port,
                        void *hosthandle)
{
        struct nvmet_fc_tgtport *tgtport = targetport_to_tgtport(target_port);
        struct nvmet_fc_tgt_assoc *assoc, *next;
        unsigned long flags;
        bool noassoc = true;

        spin_lock_irqsave(&tgtport->lock, flags);
        list_for_each_entry_safe(assoc, next,
                                &tgtport->assoc_list, a_list) {
                if (!assoc->hostport ||
                    assoc->hostport->hosthandle != hosthandle)
                        continue;
                if (!nvmet_fc_tgt_a_get(assoc))
                        continue;
                assoc->hostport->invalid = 1;
                noassoc = false;
                if (!schedule_work(&assoc->del_work))
                        /* already deleting - release local reference */
                        nvmet_fc_tgt_a_put(assoc);
        }
        spin_unlock_irqrestore(&tgtport->lock, flags);

        /* if there's nothing to wait for - call the callback */
        if (noassoc && tgtport->ops->host_release)
                tgtport->ops->host_release(hosthandle);
}
EXPORT_SYMBOL_GPL(nvmet_fc_invalidate_host);

/*
 * nvmet layer has called to terminate an association
 */
static void
nvmet_fc_delete_ctrl(struct nvmet_ctrl *ctrl)
{
        struct nvmet_fc_tgtport *tgtport, *next;
        struct nvmet_fc_tgt_assoc *assoc;
        struct nvmet_fc_tgt_queue *queue;
        unsigned long flags;
        bool found_ctrl = false;

        /* this is a bit ugly, but don't want to make locks layered */
        spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
        list_for_each_entry_safe(tgtport, next, &nvmet_fc_target_list,
                        tgt_list) {
                if (!nvmet_fc_tgtport_get(tgtport))
                        continue;
                spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);

                rcu_read_lock();
                list_for_each_entry_rcu(assoc, &tgtport->assoc_list, a_list) {
                        queue = rcu_dereference(assoc->queues[0]);
                        if (queue && queue->nvme_sq.ctrl == ctrl) {
                                if (nvmet_fc_tgt_a_get(assoc))
                                        found_ctrl = true;
                                break;
                        }
                }
                rcu_read_unlock();

                nvmet_fc_tgtport_put(tgtport);

                if (found_ctrl) {
                        if (!schedule_work(&assoc->del_work))
                                /* already deleting - release local reference */
                                nvmet_fc_tgt_a_put(assoc);
                        return;
                }

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

/**
 * nvme_fc_unregister_targetport - transport entry point called by an
 *                              LLDD to deregister/remove a previously
 *                              registered a local NVME subsystem FC port.
 * @target_port: pointer to the (registered) target port that is to be
 *               deregistered.
 *
 * Returns:
 * a completion status. Must be 0 upon success; a negative errno
 * (ex: -ENXIO) upon failure.
 */
int
nvmet_fc_unregister_targetport(struct nvmet_fc_target_port *target_port)
{
        struct nvmet_fc_tgtport *tgtport = targetport_to_tgtport(target_port);

        nvmet_fc_portentry_unbind_tgt(tgtport);

        /* terminate any outstanding associations */
        __nvmet_fc_free_assocs(tgtport);

        /*
         * should terminate LS's as well. However, LS's will be generated
         * at the tail end of association termination, so they likely don't
         * exist yet. And even if they did, it's worthwhile to just let
         * them finish and targetport ref counting will clean things up.
         */

        nvmet_fc_tgtport_put(tgtport);

        return 0;
}
EXPORT_SYMBOL_GPL(nvmet_fc_unregister_targetport);


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


static void
nvmet_fc_ls_create_association(struct nvmet_fc_tgtport *tgtport,
                        struct nvmet_fc_ls_iod *iod)
{
        struct fcnvme_ls_cr_assoc_rqst *rqst = &iod->rqstbuf->rq_cr_assoc;
        struct fcnvme_ls_cr_assoc_acc *acc = &iod->rspbuf->rsp_cr_assoc;
        struct nvmet_fc_tgt_queue *queue;
        int ret = 0;

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

        /*
         * FC-NVME spec changes. There are initiators sending different
         * lengths as padding sizes for Create Association Cmd descriptor
         * was incorrect.
         * Accept anything of "minimum" length. Assume format per 1.15
         * spec (with HOSTID reduced to 16 bytes), ignore how long the
         * trailing pad length is.
         */
        if (iod->rqstdatalen < FCNVME_LSDESC_CRA_RQST_MINLEN)
                ret = VERR_CR_ASSOC_LEN;
        else if (be32_to_cpu(rqst->desc_list_len) <
                        FCNVME_LSDESC_CRA_RQST_MIN_LISTLEN)
                ret = VERR_CR_ASSOC_RQST_LEN;
        else if (rqst->assoc_cmd.desc_tag !=
                        cpu_to_be32(FCNVME_LSDESC_CREATE_ASSOC_CMD))
                ret = VERR_CR_ASSOC_CMD;
        else if (be32_to_cpu(rqst->assoc_cmd.desc_len) <
                        FCNVME_LSDESC_CRA_CMD_DESC_MIN_DESCLEN)
                ret = VERR_CR_ASSOC_CMD_LEN;
        else if (!rqst->assoc_cmd.ersp_ratio ||
                 (be16_to_cpu(rqst->assoc_cmd.ersp_ratio) >=
                                be16_to_cpu(rqst->assoc_cmd.sqsize)))
                ret = VERR_ERSP_RATIO;

        else {
                /* new association w/ admin queue */
                iod->assoc = nvmet_fc_alloc_target_assoc(
                                                tgtport, iod->hosthandle);
                if (!iod->assoc)
                        ret = VERR_ASSOC_ALLOC_FAIL;
                else {
                        queue = nvmet_fc_alloc_target_queue(iod->assoc, 0,
                                        be16_to_cpu(rqst->assoc_cmd.sqsize));
                        if (!queue)
                                ret = VERR_QUEUE_ALLOC_FAIL;
                }
        }

        if (ret) {
                dev_err(tgtport->dev,
                        "Create Association LS failed: %s\n",
                        validation_errors[ret]);
                iod->lsrsp->rsplen = nvme_fc_format_rjt(acc,
                                sizeof(*acc), rqst->w0.ls_cmd,
                                FCNVME_RJT_RC_LOGIC,
                                FCNVME_RJT_EXP_NONE, 0);
                return;
        }

        queue->ersp_ratio = be16_to_cpu(rqst->assoc_cmd.ersp_ratio);
        atomic_set(&queue->connected, 1);
        queue->sqhd = 0;        /* best place to init value */

        dev_info(tgtport->dev,
                "{%d:%d} Association created\n",
                tgtport->fc_target_port.port_num, iod->assoc->a_id);

        /* format a response */

        iod->lsrsp->rsplen = sizeof(*acc);

        nvme_fc_format_rsp_hdr(acc, FCNVME_LS_ACC,
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_ls_cr_assoc_acc)),
                        FCNVME_LS_CREATE_ASSOCIATION);
        acc->associd.desc_tag = cpu_to_be32(FCNVME_LSDESC_ASSOC_ID);
        acc->associd.desc_len =
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_lsdesc_assoc_id));
        acc->associd.association_id =
                        cpu_to_be64(nvmet_fc_makeconnid(iod->assoc, 0));
        acc->connectid.desc_tag = cpu_to_be32(FCNVME_LSDESC_CONN_ID);
        acc->connectid.desc_len =
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_lsdesc_conn_id));
        acc->connectid.connection_id = acc->associd.association_id;
}

static void
nvmet_fc_ls_create_connection(struct nvmet_fc_tgtport *tgtport,
                        struct nvmet_fc_ls_iod *iod)
{
        struct fcnvme_ls_cr_conn_rqst *rqst = &iod->rqstbuf->rq_cr_conn;
        struct fcnvme_ls_cr_conn_acc *acc = &iod->rspbuf->rsp_cr_conn;
        struct nvmet_fc_tgt_queue *queue;
        int ret = 0;

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

        if (iod->rqstdatalen < sizeof(struct fcnvme_ls_cr_conn_rqst))
                ret = VERR_CR_CONN_LEN;
        else if (rqst->desc_list_len !=
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_ls_cr_conn_rqst)))
                ret = VERR_CR_CONN_RQST_LEN;
        else if (rqst->associd.desc_tag != cpu_to_be32(FCNVME_LSDESC_ASSOC_ID))
                ret = VERR_ASSOC_ID;
        else if (rqst->associd.desc_len !=
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_lsdesc_assoc_id)))
                ret = VERR_ASSOC_ID_LEN;
        else if (rqst->connect_cmd.desc_tag !=
                        cpu_to_be32(FCNVME_LSDESC_CREATE_CONN_CMD))
                ret = VERR_CR_CONN_CMD;
        else if (rqst->connect_cmd.desc_len !=
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_lsdesc_cr_conn_cmd)))
                ret = VERR_CR_CONN_CMD_LEN;
        else if (!rqst->connect_cmd.ersp_ratio ||
                 (be16_to_cpu(rqst->connect_cmd.ersp_ratio) >=
                                be16_to_cpu(rqst->connect_cmd.sqsize)))
                ret = VERR_ERSP_RATIO;

        else {
                /* new io queue */
                iod->assoc = nvmet_fc_find_target_assoc(tgtport,
                                be64_to_cpu(rqst->associd.association_id));
                if (!iod->assoc)
                        ret = VERR_NO_ASSOC;
                else {
                        queue = nvmet_fc_alloc_target_queue(iod->assoc,
                                        be16_to_cpu(rqst->connect_cmd.qid),
                                        be16_to_cpu(rqst->connect_cmd.sqsize));
                        if (!queue)
                                ret = VERR_QUEUE_ALLOC_FAIL;

                        /* release get taken in nvmet_fc_find_target_assoc */
                        nvmet_fc_tgt_a_put(iod->assoc);
                }
        }

        if (ret) {
                dev_err(tgtport->dev,
                        "Create Connection LS failed: %s\n",
                        validation_errors[ret]);
                iod->lsrsp->rsplen = nvme_fc_format_rjt(acc,
                                sizeof(*acc), rqst->w0.ls_cmd,
                                (ret == VERR_NO_ASSOC) ?
                                        FCNVME_RJT_RC_INV_ASSOC :
                                        FCNVME_RJT_RC_LOGIC,
                                FCNVME_RJT_EXP_NONE, 0);
                return;
        }

        queue->ersp_ratio = be16_to_cpu(rqst->connect_cmd.ersp_ratio);
        atomic_set(&queue->connected, 1);
        queue->sqhd = 0;        /* best place to init value */

        /* format a response */

        iod->lsrsp->rsplen = sizeof(*acc);

        nvme_fc_format_rsp_hdr(acc, FCNVME_LS_ACC,
                        fcnvme_lsdesc_len(sizeof(struct fcnvme_ls_cr_conn_acc)),
                        FCNVME_LS_CREATE_CONNECTION);
        acc->connectid.desc_tag = cpu_to_be32(FCNVME_LSDESC_CONN_ID);
        acc->connectid.desc_len =
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_lsdesc_conn_id));
        acc->connectid.connection_id =
                        cpu_to_be64(nvmet_fc_makeconnid(iod->assoc,
                                be16_to_cpu(rqst->connect_cmd.qid)));
}

/*
 * Returns true if the LS response is to be transmit
 * Returns false if the LS response is to be delayed
 */
static int
nvmet_fc_ls_disconnect(struct nvmet_fc_tgtport *tgtport,
                        struct nvmet_fc_ls_iod *iod)
{
        struct fcnvme_ls_disconnect_assoc_rqst *rqst =
                                                &iod->rqstbuf->rq_dis_assoc;
        struct fcnvme_ls_disconnect_assoc_acc *acc =
                                                &iod->rspbuf->rsp_dis_assoc;
        struct nvmet_fc_tgt_assoc *assoc = NULL;
        struct nvmet_fc_ls_iod *oldls = NULL;
        unsigned long flags;
        int ret = 0;

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

        ret = nvmefc_vldt_lsreq_discon_assoc(iod->rqstdatalen, rqst);
        if (!ret) {
                /* match an active association - takes an assoc ref if !NULL */
                assoc = nvmet_fc_find_target_assoc(tgtport,
                                be64_to_cpu(rqst->associd.association_id));
                iod->assoc = assoc;
                if (!assoc)
                        ret = VERR_NO_ASSOC;
        }

        if (ret || !assoc) {
                dev_err(tgtport->dev,
                        "Disconnect LS failed: %s\n",
                        validation_errors[ret]);
                iod->lsrsp->rsplen = nvme_fc_format_rjt(acc,
                                sizeof(*acc), rqst->w0.ls_cmd,
                                (ret == VERR_NO_ASSOC) ?
                                        FCNVME_RJT_RC_INV_ASSOC :
                                        FCNVME_RJT_RC_LOGIC,
                                FCNVME_RJT_EXP_NONE, 0);
                return true;
        }

        /* format a response */

        iod->lsrsp->rsplen = sizeof(*acc);

        nvme_fc_format_rsp_hdr(acc, FCNVME_LS_ACC,
                        fcnvme_lsdesc_len(
                                sizeof(struct fcnvme_ls_disconnect_assoc_acc)),
                        FCNVME_LS_DISCONNECT_ASSOC);

        /* release get taken in nvmet_fc_find_target_assoc */
        nvmet_fc_tgt_a_put(assoc);

        /*
         * The rules for LS response says the response cannot
         * go back until ABTS's have been sent for all outstanding
         * I/O and a Disconnect Association LS has been sent.
         * So... save off the Disconnect LS to send the response
         * later. If there was a prior LS already saved, replace
         * it with the newer one and send a can't perform reject
         * on the older one.
         */
        spin_lock_irqsave(&tgtport->lock, flags);
        oldls = assoc->rcv_disconn;
        assoc->rcv_disconn = iod;
        spin_unlock_irqrestore(&tgtport->lock, flags);

        nvmet_fc_delete_target_assoc(assoc);

        if (oldls) {
                dev_info(tgtport->dev,
                        "{%d:%d} Multiple Disconnect Association LS's "
                        "received\n",
                        tgtport->fc_target_port.port_num, assoc->a_id);
                /* overwrite good response with bogus failure */
                oldls->lsrsp->rsplen = nvme_fc_format_rjt(oldls->rspbuf,
                                                sizeof(*iod->rspbuf),
                                                /* ok to use rqst, LS is same */
                                                rqst->w0.ls_cmd,
                                                FCNVME_RJT_RC_UNAB,
                                                FCNVME_RJT_EXP_NONE, 0);
                nvmet_fc_xmt_ls_rsp(tgtport, oldls);
        }

        return false;
}


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


static void nvmet_fc_fcp_nvme_cmd_done(struct nvmet_req *nvme_req);

static const struct nvmet_fabrics_ops nvmet_fc_tgt_fcp_ops;

static void
nvmet_fc_xmt_ls_rsp_done(struct nvmefc_ls_rsp *lsrsp)
{
        struct nvmet_fc_ls_iod *iod = lsrsp->nvme_fc_private;
        struct nvmet_fc_tgtport *tgtport = iod->tgtport;

        fc_dma_sync_single_for_cpu(tgtport->dev, iod->rspdma,
                                sizeof(*iod->rspbuf), DMA_TO_DEVICE);
        nvmet_fc_free_ls_iod(tgtport, iod);
        nvmet_fc_tgtport_put(tgtport);
}

static void
nvmet_fc_xmt_ls_rsp(struct nvmet_fc_tgtport *tgtport,
                                struct nvmet_fc_ls_iod *iod)
{
        int ret;

        fc_dma_sync_single_for_device(tgtport->dev, iod->rspdma,
                                  sizeof(*iod->rspbuf), DMA_TO_DEVICE);

        ret = tgtport->ops->xmt_ls_rsp(&tgtport->fc_target_port, iod->lsrsp);
        if (ret)
                nvmet_fc_xmt_ls_rsp_done(iod->lsrsp);
}

/*
 * Actual processing routine for received FC-NVME LS Requests from the LLD
 */
static void
nvmet_fc_handle_ls_rqst(struct nvmet_fc_tgtport *tgtport,
                        struct nvmet_fc_ls_iod *iod)
{
        struct fcnvme_ls_rqst_w0 *w0 = &iod->rqstbuf->rq_cr_assoc.w0;
        bool sendrsp = true;

        iod->lsrsp->nvme_fc_private = iod;
        iod->lsrsp->rspbuf = iod->rspbuf;
        iod->lsrsp->rspdma = iod->rspdma;
        iod->lsrsp->done = nvmet_fc_xmt_ls_rsp_done;
        /* Be preventative. handlers will later set to valid length */
        iod->lsrsp->rsplen = 0;

        iod->assoc = NULL;

        /*
         * handlers:
         *   parse request input, execute the request, and format the
         *   LS response
         */
        switch (w0->ls_cmd) {
        case FCNVME_LS_CREATE_ASSOCIATION:
                /* Creates Association and initial Admin Queue/Connection */
                nvmet_fc_ls_create_association(tgtport, iod);
                break;
        case FCNVME_LS_CREATE_CONNECTION:
                /* Creates an IO Queue/Connection */
                nvmet_fc_ls_create_connection(tgtport, iod);
                break;
        case FCNVME_LS_DISCONNECT_ASSOC:
                /* Terminate a Queue/Connection or the Association */
                sendrsp = nvmet_fc_ls_disconnect(tgtport, iod);
                break;
        default:
                iod->lsrsp->rsplen = nvme_fc_format_rjt(iod->rspbuf,
                                sizeof(*iod->rspbuf), w0->ls_cmd,
                                FCNVME_RJT_RC_INVAL, FCNVME_RJT_EXP_NONE, 0);
        }

        if (sendrsp)
                nvmet_fc_xmt_ls_rsp(tgtport, iod);
}

/*
 * Actual processing routine for received FC-NVME LS Requests from the LLD
 */
static void
nvmet_fc_handle_ls_rqst_work(struct work_struct *work)
{
        struct nvmet_fc_ls_iod *iod =
                container_of(work, struct nvmet_fc_ls_iod, work);
        struct nvmet_fc_tgtport *tgtport = iod->tgtport;

        nvmet_fc_handle_ls_rqst(tgtport, iod);
}


/**
 * nvmet_fc_rcv_ls_req - transport entry point called by an LLDD
 *                       upon the reception of a NVME LS request.
 *
 * The nvmet-fc layer will copy payload to an internal structure for
 * processing.  As such, upon completion of the routine, the LLDD may
 * immediately free/reuse the LS request buffer passed in the call.
 *
 * If this routine returns error, the LLDD should abort the exchange.
 *
 * @target_port: pointer to the (registered) target port the LS was
 *              received on.
 * @hosthandle: pointer to the host specific data, gets stored in iod.
 * @lsrsp:      pointer to a lsrsp structure to be used to reference
 *              the exchange corresponding to the LS.
 * @lsreqbuf:   pointer to the buffer containing the LS Request
 * @lsreqbuf_len: length, in bytes, of the received LS request
 */
int
nvmet_fc_rcv_ls_req(struct nvmet_fc_target_port *target_port,
                        void *hosthandle,
                        struct nvmefc_ls_rsp *lsrsp,
                        void *lsreqbuf, u32 lsreqbuf_len)
{
        struct nvmet_fc_tgtport *tgtport = targetport_to_tgtport(target_port);
        struct nvmet_fc_ls_iod *iod;
        struct fcnvme_ls_rqst_w0 *w0 = (struct fcnvme_ls_rqst_w0 *)lsreqbuf;

        if (lsreqbuf_len > sizeof(union nvmefc_ls_requests)) {
                dev_info(tgtport->dev,
                        "RCV %s LS failed: payload too large (%d)\n",
                        (w0->ls_cmd <= NVME_FC_LAST_LS_CMD_VALUE) ?
                                nvmefc_ls_names[w0->ls_cmd] : "",
                        lsreqbuf_len);
                return -E2BIG;
        }

        if (!nvmet_fc_tgtport_get(tgtport)) {
                dev_info(tgtport->dev,
                        "RCV %s LS failed: target deleting\n",
                        (w0->ls_cmd <= NVME_FC_LAST_LS_CMD_VALUE) ?
                                nvmefc_ls_names[w0->ls_cmd] : "");
                return -ESHUTDOWN;
        }

        iod = nvmet_fc_alloc_ls_iod(tgtport);
        if (!iod) {
                dev_info(tgtport->dev,
                        "RCV %s LS failed: context allocation failed\n",
                        (w0->ls_cmd <= NVME_FC_LAST_LS_CMD_VALUE) ?
                                nvmefc_ls_names[w0->ls_cmd] : "");
                nvmet_fc_tgtport_put(tgtport);
                return -ENOENT;
        }

        iod->lsrsp = lsrsp;
        iod->fcpreq = NULL;
        memcpy(iod->rqstbuf, lsreqbuf, lsreqbuf_len);
        iod->rqstdatalen = lsreqbuf_len;
        iod->hosthandle = hosthandle;

        schedule_work(&iod->work);

        return 0;
}
EXPORT_SYMBOL_GPL(nvmet_fc_rcv_ls_req);


/*
 * **********************
 * Start of FCP handling
 * **********************
 */

static int
nvmet_fc_alloc_tgt_pgs(struct nvmet_fc_fcp_iod *fod)
{
        struct scatterlist *sg;
        unsigned int nent;

        sg = sgl_alloc(fod->req.transfer_len, GFP_KERNEL, &nent);
        if (!sg)
                goto out;

        fod->data_sg = sg;
        fod->data_sg_cnt = nent;
        fod->data_sg_cnt = fc_dma_map_sg(fod->tgtport->dev, sg, nent,
                                ((fod->io_dir == NVMET_FCP_WRITE) ?
                                        DMA_FROM_DEVICE : DMA_TO_DEVICE));
                                /* note: write from initiator perspective */
        fod->next_sg = fod->data_sg;

        return 0;

out:
        return NVME_SC_INTERNAL;
}

static void
nvmet_fc_free_tgt_pgs(struct nvmet_fc_fcp_iod *fod)
{
        if (!fod->data_sg || !fod->data_sg_cnt)
                return;

        fc_dma_unmap_sg(fod->tgtport->dev, fod->data_sg, fod->data_sg_cnt,
                                ((fod->io_dir == NVMET_FCP_WRITE) ?
                                        DMA_FROM_DEVICE : DMA_TO_DEVICE));
        sgl_free(fod->data_sg);
        fod->data_sg = NULL;
        fod->data_sg_cnt = 0;
}


static bool
queue_90percent_full(struct nvmet_fc_tgt_queue *q, u32 sqhd)
{
        u32 sqtail, used;

        /* egad, this is ugly. And sqtail is just a best guess */
        sqtail = atomic_read(&q->sqtail) % q->sqsize;

        used = (sqtail < sqhd) ? (sqtail + q->sqsize - sqhd) : (sqtail - sqhd);
        return ((used * 10) >= (((u32)(q->sqsize - 1) * 9)));
}

/*
 * Prep RSP payload.
 * May be a NVMET_FCOP_RSP or NVMET_FCOP_READDATA_RSP op
 */
static void
nvmet_fc_prep_fcp_rsp(struct nvmet_fc_tgtport *tgtport,
                                struct nvmet_fc_fcp_iod *fod)
{
        struct nvme_fc_ersp_iu *ersp = &fod->rspiubuf;
        struct nvme_common_command *sqe = &fod->cmdiubuf.sqe.common;
        struct nvme_completion *cqe = &ersp->cqe;
        u32 *cqewd = (u32 *)cqe;
        bool send_ersp = false;
        u32 rsn, rspcnt, xfr_length;

        if (fod->fcpreq->op == NVMET_FCOP_READDATA_RSP)
                xfr_length = fod->req.transfer_len;
        else
                xfr_length = fod->offset;

        /*
         * check to see if we can send a 0's rsp.
         *   Note: to send a 0's response, the NVME-FC host transport will
         *   recreate the CQE. The host transport knows: sq id, SQHD (last
         *   seen in an ersp), and command_id. Thus it will create a
         *   zero-filled CQE with those known fields filled in. Transport
         *   must send an ersp for any condition where the cqe won't match
         *   this.
         *
         * Here are the FC-NVME mandated cases where we must send an ersp:
         *  every N responses, where N=ersp_ratio
         *  force fabric commands to send ersp's (not in FC-NVME but good
         *    practice)
         *  normal cmds: any time status is non-zero, or status is zero
         *     but words 0 or 1 are non-zero.
         *  the SQ is 90% or more full
         *  the cmd is a fused command
         *  transferred data length not equal to cmd iu length
         */
        rspcnt = atomic_inc_return(&fod->queue->zrspcnt);
        if (!(rspcnt % fod->queue->ersp_ratio) ||
            nvme_is_fabrics((struct nvme_command *) sqe) ||
            xfr_length != fod->req.transfer_len ||
            (le16_to_cpu(cqe->status) & 0xFFFE) || cqewd[0] || cqewd[1] ||
            (sqe->flags & (NVME_CMD_FUSE_FIRST | NVME_CMD_FUSE_SECOND)) ||
            queue_90percent_full(fod->queue, le16_to_cpu(cqe->sq_head)))
                send_ersp = true;

        /* re-set the fields */
        fod->fcpreq->rspaddr = ersp;
        fod->fcpreq->rspdma = fod->rspdma;

        if (!send_ersp) {
                memset(ersp, 0, NVME_FC_SIZEOF_ZEROS_RSP);
                fod->fcpreq->rsplen = NVME_FC_SIZEOF_ZEROS_RSP;
        } else {
                ersp->iu_len = cpu_to_be16(sizeof(*ersp)/sizeof(u32));
                rsn = atomic_inc_return(&fod->queue->rsn);
                ersp->rsn = cpu_to_be32(rsn);
                ersp->xfrd_len = cpu_to_be32(xfr_length);
                fod->fcpreq->rsplen = sizeof(*ersp);
        }

        fc_dma_sync_single_for_device(tgtport->dev, fod->rspdma,
                                  sizeof(fod->rspiubuf), DMA_TO_DEVICE);
}

static void nvmet_fc_xmt_fcp_op_done(struct nvmefc_tgt_fcp_req *fcpreq);

static void
nvmet_fc_abort_op(struct nvmet_fc_tgtport *tgtport,
                                struct nvmet_fc_fcp_iod *fod)
{
        struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq;

        /* data no longer needed */
        nvmet_fc_free_tgt_pgs(fod);

        /*
         * if an ABTS was received or we issued the fcp_abort early
         * don't call abort routine again.
         */
        /* no need to take lock - lock was taken earlier to get here */
        if (!fod->aborted)
                tgtport->ops->fcp_abort(&tgtport->fc_target_port, fcpreq);

        nvmet_fc_free_fcp_iod(fod->queue, fod);
}

static void
nvmet_fc_xmt_fcp_rsp(struct nvmet_fc_tgtport *tgtport,
                                struct nvmet_fc_fcp_iod *fod)
{
        int ret;

        fod->fcpreq->op = NVMET_FCOP_RSP;
        fod->fcpreq->timeout = 0;

        nvmet_fc_prep_fcp_rsp(tgtport, fod);

        ret = tgtport->ops->fcp_op(&tgtport->fc_target_port, fod->fcpreq);
        if (ret)
                nvmet_fc_abort_op(tgtport, fod);
}

static void
nvmet_fc_transfer_fcp_data(struct nvmet_fc_tgtport *tgtport,
                                struct nvmet_fc_fcp_iod *fod, u8 op)
{
        struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq;
        struct scatterlist *sg = fod->next_sg;
        unsigned long flags;
        u32 remaininglen = fod->req.transfer_len - fod->offset;
        u32 tlen = 0;
        int ret;

        fcpreq->op = op;
        fcpreq->offset = fod->offset;
        fcpreq->timeout = NVME_FC_TGTOP_TIMEOUT_SEC;

        /*
         * for next sequence:
         *  break at a sg element boundary
         *  attempt to keep sequence length capped at
         *    NVMET_FC_MAX_SEQ_LENGTH but allow sequence to
         *    be longer if a single sg element is larger
         *    than that amount. This is done to avoid creating
         *    a new sg list to use for the tgtport api.
         */
        fcpreq->sg = sg;
        fcpreq->sg_cnt = 0;
        while (tlen < remaininglen &&
               fcpreq->sg_cnt < tgtport->max_sg_cnt &&
               tlen + sg_dma_len(sg) < NVMET_FC_MAX_SEQ_LENGTH) {
                fcpreq->sg_cnt++;
                tlen += sg_dma_len(sg);
                sg = sg_next(sg);
        }
        if (tlen < remaininglen && fcpreq->sg_cnt == 0) {
                fcpreq->sg_cnt++;
                tlen += min_t(u32, sg_dma_len(sg), remaininglen);
                sg = sg_next(sg);
        }
        if (tlen < remaininglen)
                fod->next_sg = sg;
        else
                fod->next_sg = NULL;

        fcpreq->transfer_length = tlen;
        fcpreq->transferred_length = 0;
        fcpreq->fcp_error = 0;
        fcpreq->rsplen = 0;

        /*
         * If the last READDATA request: check if LLDD supports
         * combined xfr with response.
         */
        if ((op == NVMET_FCOP_READDATA) &&
            ((fod->offset + fcpreq->transfer_length) == fod->req.transfer_len) &&
            (tgtport->ops->target_features & NVMET_FCTGTFEAT_READDATA_RSP)) {
                fcpreq->op = NVMET_FCOP_READDATA_RSP;
                nvmet_fc_prep_fcp_rsp(tgtport, fod);
        }

        ret = tgtport->ops->fcp_op(&tgtport->fc_target_port, fod->fcpreq);
        if (ret) {
                /*
                 * should be ok to set w/o lock as its in the thread of
                 * execution (not an async timer routine) and doesn't
                 * contend with any clearing action
                 */
                fod->abort = true;

                if (op == NVMET_FCOP_WRITEDATA) {
                        spin_lock_irqsave(&fod->flock, flags);
                        fod->writedataactive = false;
                        spin_unlock_irqrestore(&fod->flock, flags);
                        nvmet_req_complete(&fod->req, NVME_SC_INTERNAL);
                } else /* NVMET_FCOP_READDATA or NVMET_FCOP_READDATA_RSP */ {
                        fcpreq->fcp_error = ret;
                        fcpreq->transferred_length = 0;
                        nvmet_fc_xmt_fcp_op_done(fod->fcpreq);
                }
        }
}

static inline bool
__nvmet_fc_fod_op_abort(struct nvmet_fc_fcp_iod *fod, bool abort)
{
        struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq;
        struct nvmet_fc_tgtport *tgtport = fod->tgtport;

        /* if in the middle of an io and we need to tear down */
        if (abort) {
                if (fcpreq->op == NVMET_FCOP_WRITEDATA) {
                        nvmet_req_complete(&fod->req, NVME_SC_INTERNAL);
                        return true;
                }

                nvmet_fc_abort_op(tgtport, fod);
                return true;
        }

        return false;
}

/*
 * actual done handler for FCP operations when completed by the lldd
 */
static void
nvmet_fc_fod_op_done(struct nvmet_fc_fcp_iod *fod)
{
        struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq;
        struct nvmet_fc_tgtport *tgtport = fod->tgtport;
        unsigned long flags;
        bool abort;

        spin_lock_irqsave(&fod->flock, flags);
        abort = fod->abort;
        fod->writedataactive = false;
        spin_unlock_irqrestore(&fod->flock, flags);

        switch (fcpreq->op) {

        case NVMET_FCOP_WRITEDATA:
                if (__nvmet_fc_fod_op_abort(fod, abort))
                        return;
                if (fcpreq->fcp_error ||
                    fcpreq->transferred_length != fcpreq->transfer_length) {
                        spin_lock_irqsave(&fod->flock, flags);
                        fod->abort = true;
                        spin_unlock_irqrestore(&fod->flock, flags);

                        nvmet_req_complete(&fod->req, NVME_SC_INTERNAL);
                        return;
                }

                fod->offset += fcpreq->transferred_length;
                if (fod->offset != fod->req.transfer_len) {
                        spin_lock_irqsave(&fod->flock, flags);
                        fod->writedataactive = true;
                        spin_unlock_irqrestore(&fod->flock, flags);

                        /* transfer the next chunk */
                        nvmet_fc_transfer_fcp_data(tgtport, fod,
                                                NVMET_FCOP_WRITEDATA);
                        return;
                }

                /* data transfer complete, resume with nvmet layer */
                fod->req.execute(&fod->req);
                break;

        case NVMET_FCOP_READDATA:
        case NVMET_FCOP_READDATA_RSP:
                if (__nvmet_fc_fod_op_abort(fod, abort))
                        return;
                if (fcpreq->fcp_error ||
                    fcpreq->transferred_length != fcpreq->transfer_length) {
                        nvmet_fc_abort_op(tgtport, fod);
                        return;
                }

                /* success */

                if (fcpreq->op == NVMET_FCOP_READDATA_RSP) {
                        /* data no longer needed */
                        nvmet_fc_free_tgt_pgs(fod);
                        nvmet_fc_free_fcp_iod(fod->queue, fod);
                        return;
                }

                fod->offset += fcpreq->transferred_length;
                if (fod->offset != fod->req.transfer_len) {
                        /* transfer the next chunk */
                        nvmet_fc_transfer_fcp_data(tgtport, fod,
                                                NVMET_FCOP_READDATA);
                        return;
                }

                /* data transfer complete, send response */

                /* data no longer needed */
                nvmet_fc_free_tgt_pgs(fod);

                nvmet_fc_xmt_fcp_rsp(tgtport, fod);

                break;

        case NVMET_FCOP_RSP:
                if (__nvmet_fc_fod_op_abort(fod, abort))
                        return;
                nvmet_fc_free_fcp_iod(fod->queue, fod);
                break;

        default:
                break;
        }
}

static void
nvmet_fc_xmt_fcp_op_done(struct nvmefc_tgt_fcp_req *fcpreq)
{
        struct nvmet_fc_fcp_iod *fod = fcpreq->nvmet_fc_private;

        nvmet_fc_fod_op_done(fod);
}

/*
 * actual completion handler after execution by the nvmet layer
 */
static void
__nvmet_fc_fcp_nvme_cmd_done(struct nvmet_fc_tgtport *tgtport,
                        struct nvmet_fc_fcp_iod *fod, int status)
{
        struct nvme_common_command *sqe = &fod->cmdiubuf.sqe.common;
        struct nvme_completion *cqe = &fod->rspiubuf.cqe;
        unsigned long flags;
        bool abort;

        spin_lock_irqsave(&fod->flock, flags);
        abort = fod->abort;
        spin_unlock_irqrestore(&fod->flock, flags);

        /* if we have a CQE, snoop the last sq_head value */
        if (!status)
                fod->queue->sqhd = cqe->sq_head;

        if (abort) {
                nvmet_fc_abort_op(tgtport, fod);
                return;
        }

        /* if an error handling the cmd post initial parsing */
        if (status) {
                /* fudge up a failed CQE status for our transport error */
                memset(cqe, 0, sizeof(*cqe));
                cqe->sq_head = fod->queue->sqhd;        /* echo last cqe sqhd */
                cqe->sq_id = cpu_to_le16(fod->queue->qid);
                cqe->command_id = sqe->command_id;
                cqe->status = cpu_to_le16(status);
        } else {

                /*
                 * try to push the data even if the SQE status is non-zero.
                 * There may be a status where data still was intended to
                 * be moved
                 */
                if ((fod->io_dir == NVMET_FCP_READ) && (fod->data_sg_cnt)) {
                        /* push the data over before sending rsp */
                        nvmet_fc_transfer_fcp_data(tgtport, fod,
                                                NVMET_FCOP_READDATA);
                        return;
                }

                /* writes & no data - fall thru */
        }

        /* data no longer needed */
        nvmet_fc_free_tgt_pgs(fod);

        nvmet_fc_xmt_fcp_rsp(tgtport, fod);
}


static void
nvmet_fc_fcp_nvme_cmd_done(struct nvmet_req *nvme_req)
{
        struct nvmet_fc_fcp_iod *fod = nvmet_req_to_fod(nvme_req);
        struct nvmet_fc_tgtport *tgtport = fod->tgtport;

        __nvmet_fc_fcp_nvme_cmd_done(tgtport, fod, 0);
}


/*
 * Actual processing routine for received FC-NVME I/O Requests from the LLD
 */
static void
nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
                        struct nvmet_fc_fcp_iod *fod)
{
        struct nvme_fc_cmd_iu *cmdiu = &fod->cmdiubuf;
        u32 xfrlen = be32_to_cpu(cmdiu->data_len);
        int ret;

        /*
         * Fused commands are currently not supported in the linux
         * implementation.
         *
         * As such, the implementation of the FC transport does not
         * look at the fused commands and order delivery to the upper
         * layer until we have both based on csn.
         */

        fod->fcpreq->done = nvmet_fc_xmt_fcp_op_done;

        if (cmdiu->flags & FCNVME_CMD_FLAGS_WRITE) {
                fod->io_dir = NVMET_FCP_WRITE;
                if (!nvme_is_write(&cmdiu->sqe))
                        goto transport_error;
        } else if (cmdiu->flags & FCNVME_CMD_FLAGS_READ) {
                fod->io_dir = NVMET_FCP_READ;
                if (nvme_is_write(&cmdiu->sqe))
                        goto transport_error;
        } else {
                fod->io_dir = NVMET_FCP_NODATA;
                if (xfrlen)
                        goto transport_error;
        }

        fod->req.cmd = &fod->cmdiubuf.sqe;
        fod->req.cqe = &fod->rspiubuf.cqe;
        if (tgtport->pe)
                fod->req.port = tgtport->pe->port;

        /* clear any response payload */
        memset(&fod->rspiubuf, 0, sizeof(fod->rspiubuf));

        fod->data_sg = NULL;
        fod->data_sg_cnt = 0;

        ret = nvmet_req_init(&fod->req,
                                &fod->queue->nvme_cq,
                                &fod->queue->nvme_sq,
                                &nvmet_fc_tgt_fcp_ops);
        if (!ret) {
                /* bad SQE content or invalid ctrl state */
                /* nvmet layer has already called op done to send rsp. */
                return;
        }

        fod->req.transfer_len = xfrlen;

        /* keep a running counter of tail position */
        atomic_inc(&fod->queue->sqtail);

        if (fod->req.transfer_len) {
                ret = nvmet_fc_alloc_tgt_pgs(fod);
                if (ret) {
                        nvmet_req_complete(&fod->req, ret);
                        return;
                }
        }
        fod->req.sg = fod->data_sg;
        fod->req.sg_cnt = fod->data_sg_cnt;
        fod->offset = 0;

        if (fod->io_dir == NVMET_FCP_WRITE) {
                /* pull the data over before invoking nvmet layer */
                nvmet_fc_transfer_fcp_data(tgtport, fod, NVMET_FCOP_WRITEDATA);
                return;
        }

        /*
         * Reads or no data:
         *
         * can invoke the nvmet_layer now. If read data, cmd completion will
         * push the data
         */
        fod->req.execute(&fod->req);
        return;

transport_error:
        nvmet_fc_abort_op(tgtport, fod);
}

/**
 * nvmet_fc_rcv_fcp_req - transport entry point called by an LLDD
 *                       upon the reception of a NVME FCP CMD IU.
 *
 * Pass a FC-NVME FCP CMD IU received from the FC link to the nvmet-fc
 * layer for processing.
 *
 * The nvmet_fc layer allocates a local job structure (struct
 * nvmet_fc_fcp_iod) from the queue for the io and copies the
 * CMD IU buffer to the job structure. As such, on a successful
 * completion (returns 0), the LLDD may immediately free/reuse
 * the CMD IU buffer passed in the call.
 *
 * However, in some circumstances, due to the packetized nature of FC
 * and the api of the FC LLDD which may issue a hw command to send the
 * response, but the LLDD may not get the hw completion for that command
 * and upcall the nvmet_fc layer before a new command may be
 * asynchronously received - its possible for a command to be received
 * before the LLDD and nvmet_fc have recycled the job structure. It gives
 * the appearance of more commands received than fits in the sq.
 * To alleviate this scenario, a temporary queue is maintained in the
 * transport for pending LLDD requests waiting for a queue job structure.
 * In these "overrun" cases, a temporary queue element is allocated
 * the LLDD request and CMD iu buffer information remembered, and the
 * routine returns a -EOVERFLOW status. Subsequently, when a queue job
 * structure is freed, it is immediately reallocated for anything on the
 * pending request list. The LLDDs defer_rcv() callback is called,
 * informing the LLDD that it may reuse the CMD IU buffer, and the io
 * is then started normally with the transport.
 *
 * The LLDD, when receiving an -EOVERFLOW completion status, is to treat
 * the completion as successful but must not reuse the CMD IU buffer
 * until the LLDD's defer_rcv() callback has been called for the
 * corresponding struct nvmefc_tgt_fcp_req pointer.
 *
 * If there is any other condition in which an error occurs, the
 * transport will return a non-zero status indicating the error.
 * In all cases other than -EOVERFLOW, the transport has not accepted the
 * request and the LLDD should abort the exchange.
 *
 * @target_port: pointer to the (registered) target port the FCP CMD IU
 *              was received on.
 * @fcpreq:     pointer to a fcpreq request structure to be used to reference
 *              the exchange corresponding to the FCP Exchange.
 * @cmdiubuf:   pointer to the buffer containing the FCP CMD IU
 * @cmdiubuf_len: length, in bytes, of the received FCP CMD IU
 */
int
nvmet_fc_rcv_fcp_req(struct nvmet_fc_target_port *target_port,
                        struct nvmefc_tgt_fcp_req *fcpreq,
                        void *cmdiubuf, u32 cmdiubuf_len)
{
        struct nvmet_fc_tgtport *tgtport = targetport_to_tgtport(target_port);
        struct nvme_fc_cmd_iu *cmdiu = cmdiubuf;
        struct nvmet_fc_tgt_queue *queue;
        struct nvmet_fc_fcp_iod *fod;
        struct nvmet_fc_defer_fcp_req *deferfcp;
        unsigned long flags;

        /* validate iu, so the connection id can be used to find the queue */
        if ((cmdiubuf_len != sizeof(*cmdiu)) ||
                        (cmdiu->format_id != NVME_CMD_FORMAT_ID) ||
                        (cmdiu->fc_id != NVME_CMD_FC_ID) ||
                        (be16_to_cpu(cmdiu->iu_len) != (sizeof(*cmdiu)/4)))
                return -EIO;

        queue = nvmet_fc_find_target_queue(tgtport,
                                be64_to_cpu(cmdiu->connection_id));
        if (!queue)
                return -ENOTCONN;

        /*
         * note: reference taken by find_target_queue
         * After successful fod allocation, the fod will inherit the
         * ownership of that reference and will remove the reference
         * when the fod is freed.
         */

        spin_lock_irqsave(&queue->qlock, flags);

        fod = nvmet_fc_alloc_fcp_iod(queue);
        if (fod) {
                spin_unlock_irqrestore(&queue->qlock, flags);

                fcpreq->nvmet_fc_private = fod;
                fod->fcpreq = fcpreq;

                memcpy(&fod->cmdiubuf, cmdiubuf, cmdiubuf_len);

                nvmet_fc_queue_fcp_req(tgtport, queue, fcpreq);

                return 0;
        }

        if (!tgtport->ops->defer_rcv) {
                spin_unlock_irqrestore(&queue->qlock, flags);
                /* release the queue lookup reference */
                nvmet_fc_tgt_q_put(queue);
                return -ENOENT;
        }

        deferfcp = list_first_entry_or_null(&queue->avail_defer_list,
                        struct nvmet_fc_defer_fcp_req, req_list);
        if (deferfcp) {
                /* Just re-use one that was previously allocated */
                list_del(&deferfcp->req_list);
        } else {
                spin_unlock_irqrestore(&queue->qlock, flags);

                /* Now we need to dynamically allocate one */
                deferfcp = kmalloc(sizeof(*deferfcp), GFP_KERNEL);
                if (!deferfcp) {
                        /* release the queue lookup reference */
                        nvmet_fc_tgt_q_put(queue);
                        return -ENOMEM;
                }
                spin_lock_irqsave(&queue->qlock, flags);
        }

        /* For now, use rspaddr / rsplen to save payload information */
        fcpreq->rspaddr = cmdiubuf;
        fcpreq->rsplen  = cmdiubuf_len;
        deferfcp->fcp_req = fcpreq;

        /* defer processing till a fod becomes available */
        list_add_tail(&deferfcp->req_list, &queue->pending_cmd_list);

        /* NOTE: the queue lookup reference is still valid */

        spin_unlock_irqrestore(&queue->qlock, flags);

        return -EOVERFLOW;
}
EXPORT_SYMBOL_GPL(nvmet_fc_rcv_fcp_req);

/**
 * nvmet_fc_rcv_fcp_abort - transport entry point called by an LLDD
 *                       upon the reception of an ABTS for a FCP command
 *
 * Notify the transport that an ABTS has been received for a FCP command
 * that had been given to the transport via nvmet_fc_rcv_fcp_req(). The
 * LLDD believes the command is still being worked on
 * (template_ops->fcp_req_release() has not been called).
 *
 * The transport will wait for any outstanding work (an op to the LLDD,
 * which the lldd should complete with error due to the ABTS; or the
 * completion from the nvmet layer of the nvme command), then will
 * stop processing and call the nvmet_fc_rcv_fcp_req() callback to
 * return the i/o context to the LLDD.  The LLDD may send the BA_ACC
 * to the ABTS either after return from this function (assuming any
 * outstanding op work has been terminated) or upon the callback being
 * called.
 *
 * @target_port: pointer to the (registered) target port the FCP CMD IU
 *              was received on.
 * @fcpreq:     pointer to the fcpreq request structure that corresponds
 *              to the exchange that received the ABTS.
 */
void
nvmet_fc_rcv_fcp_abort(struct nvmet_fc_target_port *target_port,
                        struct nvmefc_tgt_fcp_req *fcpreq)
{
        struct nvmet_fc_fcp_iod *fod = fcpreq->nvmet_fc_private;
        struct nvmet_fc_tgt_queue *queue;
        unsigned long flags;

        if (!fod || fod->fcpreq != fcpreq)
                /* job appears to have already completed, ignore abort */
                return;

        queue = fod->queue;

        spin_lock_irqsave(&queue->qlock, flags);
        if (fod->active) {
                /*
                 * mark as abort. The abort handler, invoked upon completion
                 * of any work, will detect the aborted status and do the
                 * callback.
                 */
                spin_lock(&fod->flock);
                fod->abort = true;
                fod->aborted = true;
                spin_unlock(&fod->flock);
        }
        spin_unlock_irqrestore(&queue->qlock, flags);
}
EXPORT_SYMBOL_GPL(nvmet_fc_rcv_fcp_abort);


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 int
nvmet_fc_add_port(struct nvmet_port *port)
{
        struct nvmet_fc_tgtport *tgtport;
        struct nvmet_fc_port_entry *pe;
        struct nvmet_fc_traddr traddr = { 0L, 0L };
        unsigned long flags;
        int ret;

        /* validate the address info */
        if ((port->disc_addr.trtype != NVMF_TRTYPE_FC) ||
            (port->disc_addr.adrfam != NVMF_ADDR_FAMILY_FC))
                return -EINVAL;

        /* map the traddr address info to a target port */

        ret = nvme_fc_parse_traddr(&traddr, port->disc_addr.traddr,
                        sizeof(port->disc_addr.traddr));
        if (ret)
                return ret;

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

        ret = -ENXIO;
        spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
        list_for_each_entry(tgtport, &nvmet_fc_target_list, tgt_list) {
                if ((tgtport->fc_target_port.node_name == traddr.nn) &&
                    (tgtport->fc_target_port.port_name == traddr.pn)) {
                        /* a FC port can only be 1 nvmet port id */
                        if (!tgtport->pe) {
                                nvmet_fc_portentry_bind(tgtport, pe, port);
                                ret = 0;
                        } else
                                ret = -EALREADY;
                        break;
                }
        }
        spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);

        if (ret)
                kfree(pe);

        return ret;
}

static void
nvmet_fc_remove_port(struct nvmet_port *port)
{
        struct nvmet_fc_port_entry *pe = port->priv;

        nvmet_fc_portentry_unbind(pe);

        kfree(pe);
}

static void
nvmet_fc_discovery_chg(struct nvmet_port *port)
{
        struct nvmet_fc_port_entry *pe = port->priv;
        struct nvmet_fc_tgtport *tgtport = pe->tgtport;

        if (tgtport && tgtport->ops->discovery_event)
                tgtport->ops->discovery_event(&tgtport->fc_target_port);
}

static const struct nvmet_fabrics_ops nvmet_fc_tgt_fcp_ops = {
        .owner                  = THIS_MODULE,
        .type                   = NVMF_TRTYPE_FC,
        .msdbd                  = 1,
        .add_port               = nvmet_fc_add_port,
        .remove_port            = nvmet_fc_remove_port,
        .queue_response         = nvmet_fc_fcp_nvme_cmd_done,
        .delete_ctrl            = nvmet_fc_delete_ctrl,
        .discovery_chg          = nvmet_fc_discovery_chg,
};

static int __init nvmet_fc_init_module(void)
{
        return nvmet_register_transport(&nvmet_fc_tgt_fcp_ops);
}

static void __exit nvmet_fc_exit_module(void)
{
        /* sanity check - all lports should be removed */
        if (!list_empty(&nvmet_fc_target_list))
                pr_warn("%s: targetport list not empty\n", __func__);

        nvmet_unregister_transport(&nvmet_fc_tgt_fcp_ops);

        ida_destroy(&nvmet_fc_tgtport_cnt);
}

module_init(nvmet_fc_init_module);
module_exit(nvmet_fc_exit_module);

MODULE_LICENSE("GPL v2");