/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lnet/klnds/o2iblnd/o2iblnd.h
 *
 * Author: Eric Barton <eric@bartonsoftware.com>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/uio.h>

#include <asm/uaccess.h>
#include <asm/io.h>

#include <linux/fs.h>
#include <linux/file.h>
#include <linux/list.h>
#include <linux/kmod.h>
#include <linux/sysctl.h>
#include <linux/pci.h>

#include <net/sock.h>
#include <linux/in.h>

#define DEBUG_SUBSYSTEM S_LND

#include "../../../include/linux/libcfs/libcfs.h"
#include "../../../include/linux/lnet/lnet.h"
#include "../../../include/linux/lnet/lib-lnet.h"
#include "../../../include/linux/lnet/lnet-sysctl.h"

#include <rdma/rdma_cm.h>
#include <rdma/ib_cm.h>
#include <rdma/ib_verbs.h>
#include <rdma/ib_fmr_pool.h>

#define IBLND_PEER_HASH_SIZE            101     /* # peer lists */
/* # scheduler loops before reschedule */
#define IBLND_RESCHED                   100

#define IBLND_N_SCHED                   2
#define IBLND_N_SCHED_HIGH              4

typedef struct {
        int           *kib_dev_failover;     /* HCA failover */
        unsigned int     *kib_service;    /* IB service number */
        int           *kib_min_reconnect_interval; /* first failed connection retry... */
        int           *kib_max_reconnect_interval; /* ...exponentially increasing to this */
        int           *kib_cksum;           /* checksum kib_msg_t? */
        int           *kib_timeout;       /* comms timeout (seconds) */
        int           *kib_keepalive;   /* keepalive timeout (seconds) */
        int           *kib_ntx;       /* # tx descs */
        int           *kib_credits;       /* # concurrent sends */
        int           *kib_peertxcredits;    /* # concurrent sends to 1 peer */
        int           *kib_peerrtrcredits;   /* # per-peer router buffer credits */
        int           *kib_peercredits_hiw;  /* # when eagerly to return credits */
        int           *kib_peertimeout;      /* seconds to consider peer dead */
        char        **kib_default_ipif;     /* default IPoIB interface */
        int           *kib_retry_count;
        int           *kib_rnr_retry_count;
        int           *kib_concurrent_sends; /* send work queue sizing */
        int              *kib_ib_mtu;           /* IB MTU */
        int           *kib_map_on_demand;    /* map-on-demand if RD has more fragments
                                                 * than this value, 0 disable map-on-demand */
        int           *kib_pmr_pool_size;    /* # physical MR in pool */
        int           *kib_fmr_pool_size;    /* # FMRs in pool */
        int           *kib_fmr_flush_trigger; /* When to trigger FMR flush */
        int           *kib_fmr_cache;   /* enable FMR pool cache? */
        int           *kib_require_priv_port;/* accept only privileged ports */
        int           *kib_use_priv_port;    /* use privileged port for active connect */
        /* # threads on each CPT */
        int              *kib_nscheds;
} kib_tunables_t;

extern kib_tunables_t  kiblnd_tunables;

#define IBLND_MSG_QUEUE_SIZE_V1      8    /* V1 only : # messages/RDMAs in-flight */
#define IBLND_CREDIT_HIGHWATER_V1    7    /* V1 only : when eagerly to return credits */

#define IBLND_CREDITS_DEFAULT   8         /* default # of peer credits */
#define IBLND_CREDITS_MAX         ((typeof(((kib_msg_t*) 0)->ibm_credits)) - 1)  /* Max # of peer credits */

#define IBLND_MSG_QUEUE_SIZE(v)    ((v) == IBLND_MSG_VERSION_1 ? \
                                     IBLND_MSG_QUEUE_SIZE_V1 :   \
                                     *kiblnd_tunables.kib_peertxcredits) /* # messages/RDMAs in-flight */
#define IBLND_CREDITS_HIGHWATER(v) ((v) == IBLND_MSG_VERSION_1 ? \
                                     IBLND_CREDIT_HIGHWATER_V1 : \
                                     *kiblnd_tunables.kib_peercredits_hiw) /* when eagerly to return credits */

#define kiblnd_rdma_create_id(cb, dev, ps, qpt) rdma_create_id(cb, dev, ps, qpt)

static inline int
kiblnd_concurrent_sends_v1(void)
{
        if (*kiblnd_tunables.kib_concurrent_sends > IBLND_MSG_QUEUE_SIZE_V1 * 2)
                return IBLND_MSG_QUEUE_SIZE_V1 * 2;

        if (*kiblnd_tunables.kib_concurrent_sends < IBLND_MSG_QUEUE_SIZE_V1 / 2)
                return IBLND_MSG_QUEUE_SIZE_V1 / 2;

        return *kiblnd_tunables.kib_concurrent_sends;
}

#define IBLND_CONCURRENT_SENDS(v)  ((v) == IBLND_MSG_VERSION_1 ? \
                                     kiblnd_concurrent_sends_v1() : \
                                     *kiblnd_tunables.kib_concurrent_sends)
/* 2 OOB shall suffice for 1 keepalive and 1 returning credits */
#define IBLND_OOB_CAPABLE(v)       ((v) != IBLND_MSG_VERSION_1)
#define IBLND_OOB_MSGS(v)          (IBLND_OOB_CAPABLE(v) ? 2 : 0)

#define IBLND_MSG_SIZE        (4<<10)            /* max size of queued messages (inc hdr) */
#define IBLND_MAX_RDMA_FRAGS     LNET_MAX_IOV      /* max # of fragments supported */
#define IBLND_CFG_RDMA_FRAGS       (*kiblnd_tunables.kib_map_on_demand != 0 ? \
                                    *kiblnd_tunables.kib_map_on_demand :      \
                                     IBLND_MAX_RDMA_FRAGS)  /* max # of fragments configured by user */
#define IBLND_RDMA_FRAGS(v)     ((v) == IBLND_MSG_VERSION_1 ? \
                                     IBLND_MAX_RDMA_FRAGS : IBLND_CFG_RDMA_FRAGS)

/************************/
/* derived constants... */
/* Pools (shared by connections on each CPT) */
/* These pools can grow at runtime, so don't need give a very large value */
#define IBLND_TX_POOL                   256
#define IBLND_PMR_POOL                  256
#define IBLND_FMR_POOL                  256
#define IBLND_FMR_POOL_FLUSH            192

/* TX messages (shared by all connections) */
#define IBLND_TX_MSGS()     (*kiblnd_tunables.kib_ntx)

/* RX messages (per connection) */
#define IBLND_RX_MSGS(v)            (IBLND_MSG_QUEUE_SIZE(v) * 2 + IBLND_OOB_MSGS(v))
#define IBLND_RX_MSG_BYTES(v)       (IBLND_RX_MSGS(v) * IBLND_MSG_SIZE)
#define IBLND_RX_MSG_PAGES(v)      ((IBLND_RX_MSG_BYTES(v) + PAGE_SIZE - 1) / PAGE_SIZE)

/* WRs and CQEs (per connection) */
#define IBLND_RECV_WRS(v)           IBLND_RX_MSGS(v)
#define IBLND_SEND_WRS(v)         ((IBLND_RDMA_FRAGS(v) + 1) * IBLND_CONCURRENT_SENDS(v))
#define IBLND_CQ_ENTRIES(v)      (IBLND_RECV_WRS(v) + IBLND_SEND_WRS(v))

struct kib_hca_dev;

/* o2iblnd can run over aliased interface */
#ifdef IFALIASZ
#define KIB_IFNAME_SIZE       IFALIASZ
#else
#define KIB_IFNAME_SIZE       256
#endif

typedef struct {
        struct list_head           ibd_list;      /* chain on kib_devs */
        struct list_head           ibd_fail_list;     /* chain on kib_failed_devs */
        __u32           ibd_ifip;         /* IPoIB interface IP */
        /** IPoIB interface name */
        char             ibd_ifname[KIB_IFNAME_SIZE];
        int               ibd_nnets;     /* # nets extant */

        unsigned long      ibd_next_failover;
        int               ibd_failed_failover; /* # failover failures */
        unsigned int     ibd_failover;      /* failover in progress */
        unsigned int     ibd_can_failover;  /* IPoIB interface is a bonding master */
        struct list_head           ibd_nets;
        struct kib_hca_dev  *ibd_hdev;
} kib_dev_t;

typedef struct kib_hca_dev {
        struct rdma_cm_id   *ibh_cmid;    /* listener cmid */
        struct ib_device    *ibh_ibdev;  /* IB device */
        int               ibh_page_shift;    /* page shift of current HCA */
        int               ibh_page_size;     /* page size of current HCA */
        __u64           ibh_page_mask;     /* page mask of current HCA */
        int               ibh_mr_shift;      /* bits shift of max MR size */
        __u64           ibh_mr_size;       /* size of MR */
        int               ibh_nmrs;       /* # of global MRs */
        struct ib_mr       **ibh_mrs;      /* global MR */
        struct ib_pd    *ibh_pd;            /* PD */
        kib_dev_t          *ibh_dev;       /* owner */
        atomic_t         ibh_ref;          /* refcount */
} kib_hca_dev_t;

/** # of seconds to keep pool alive */
#define IBLND_POOL_DEADLINE     300
/** # of seconds to retry if allocation failed */
#define IBLND_POOL_RETRY        1

typedef struct {
        int                  ibp_npages;             /* # pages */
        struct page         *ibp_pages[0];         /* page array */
} kib_pages_t;

struct kib_pmr_pool;

typedef struct {
        struct list_head              pmr_list;        /* chain node */
        struct ib_phys_buf     *pmr_ipb;                /* physical buffer */
        struct ib_mr       *pmr_mr;              /* IB MR */
        struct kib_pmr_pool    *pmr_pool;              /* owner of this MR */
        __u64              pmr_iova;           /* Virtual I/O address */
        int                  pmr_refcount;         /* reference count */
} kib_phys_mr_t;

struct kib_pool;
struct kib_poolset;

typedef int  (*kib_ps_pool_create_t)(struct kib_poolset *ps,
                                     int inc, struct kib_pool **pp_po);
typedef void (*kib_ps_pool_destroy_t)(struct kib_pool *po);
typedef void (*kib_ps_node_init_t)(struct kib_pool *po, struct list_head *node);
typedef void (*kib_ps_node_fini_t)(struct kib_pool *po, struct list_head *node);

struct kib_net;

#define IBLND_POOL_NAME_LEN     32

typedef struct kib_poolset {
        spinlock_t              ps_lock;                /* serialize */
        struct kib_net   *ps_net;                /* network it belongs to */
        char                ps_name[IBLND_POOL_NAME_LEN]; /* pool set name */
        struct list_head              ps_pool_list;        /* list of pools */
        struct list_head              ps_failed_pool_list;    /* failed pool list */
        unsigned long         ps_next_retry;      /* time stamp for retry if failed to allocate */
        int                  ps_increasing;       /* is allocating new pool */
        int                  ps_pool_size;         /* new pool size */
        int                     ps_cpt;                 /* CPT id */

        kib_ps_pool_create_t    ps_pool_create;  /* create a new pool */
        kib_ps_pool_destroy_t   ps_pool_destroy;        /* destroy a pool */
        kib_ps_node_init_t      ps_node_init;      /* initialize new allocated node */
        kib_ps_node_fini_t      ps_node_fini;      /* finalize node */
} kib_poolset_t;

typedef struct kib_pool {
        struct list_head              po_list;          /* chain on pool list */
        struct list_head              po_free_list;        /* pre-allocated node */
        kib_poolset_t     *po_owner;           /* pool_set of this pool */
        unsigned long         po_deadline;          /* deadline of this pool */
        int                  po_allocated;         /* # of elements in use */
        int                  po_failed;       /* pool is created on failed HCA */
        int                  po_size;           /* # of pre-allocated elements */
} kib_pool_t;

typedef struct {
        kib_poolset_t      tps_poolset;     /* pool-set */
        __u64              tps_next_tx_cookie;     /* cookie of TX */
} kib_tx_poolset_t;

typedef struct {
        kib_pool_t            tpo_pool;        /* pool */
        struct kib_hca_dev     *tpo_hdev;              /* device for this pool */
        struct kib_tx     *tpo_tx_descs;           /* all the tx descriptors */
        kib_pages_t         *tpo_tx_pages;         /* premapped tx msg pages */
} kib_tx_pool_t;

typedef struct {
        kib_poolset_t      pps_poolset;     /* pool-set */
} kib_pmr_poolset_t;

typedef struct kib_pmr_pool {
        struct kib_hca_dev     *ppo_hdev;              /* device for this pool */
        kib_pool_t            ppo_pool;        /* pool */
} kib_pmr_pool_t;

typedef struct {
        spinlock_t              fps_lock;               /* serialize */
        struct kib_net   *fps_net;              /* IB network */
        struct list_head              fps_pool_list;      /* FMR pool list */
        struct list_head              fps_failed_pool_list;   /* FMR pool list */
        __u64              fps_version;     /* validity stamp */
        int                     fps_cpt;                /* CPT id */
        int                     fps_pool_size;
        int                     fps_flush_trigger;
        /* is allocating new pool */
        int                     fps_increasing;
        /* time stamp for retry if failed to allocate */
        unsigned long           fps_next_retry;
} kib_fmr_poolset_t;

typedef struct {
        struct list_head              fpo_list;        /* chain on pool list */
        struct kib_hca_dev     *fpo_hdev;              /* device for this pool */
        kib_fmr_poolset_t      *fpo_owner;            /* owner of this pool */
        struct ib_fmr_pool     *fpo_fmr_pool;      /* IB FMR pool */
        unsigned long         fpo_deadline;        /* deadline of this pool */
        int                  fpo_failed;             /* fmr pool is failed */
        int                  fpo_map_count;       /* # of mapped FMR */
} kib_fmr_pool_t;

typedef struct {
        struct ib_pool_fmr     *fmr_pfmr;              /* IB pool fmr */
        kib_fmr_pool_t   *fmr_pool;            /* pool of FMR */
} kib_fmr_t;

typedef struct kib_net {
        struct list_head           ibn_list;      /* chain on kib_dev_t::ibd_nets */
        __u64           ibn_incarnation;   /* my epoch */
        int               ibn_init;       /* initialisation state */
        int               ibn_shutdown;      /* shutting down? */

        atomic_t                ibn_npeers;     /* # peers extant */
        atomic_t                ibn_nconns;     /* # connections extant */

        kib_tx_poolset_t        **ibn_tx_ps;    /* tx pool-set */
        kib_fmr_poolset_t       **ibn_fmr_ps;   /* fmr pool-set */
        kib_pmr_poolset_t       **ibn_pmr_ps;   /* pmr pool-set */

        kib_dev_t               *ibn_dev;       /* underlying IB device */
} kib_net_t;

#define KIB_THREAD_SHIFT                16
#define KIB_THREAD_ID(cpt, tid)         ((cpt) << KIB_THREAD_SHIFT | (tid))
#define KIB_THREAD_CPT(id)              ((id) >> KIB_THREAD_SHIFT)
#define KIB_THREAD_TID(id)              ((id) & ((1UL << KIB_THREAD_SHIFT) - 1))

struct kib_sched_info {
        /* serialise */
        spinlock_t              ibs_lock;
        /* schedulers sleep here */
        wait_queue_head_t               ibs_waitq;
        /* conns to check for rx completions */
        struct list_head                ibs_conns;
        /* number of scheduler threads */
        int                     ibs_nthreads;
        /* max allowed scheduler threads */
        int                     ibs_nthreads_max;
        int                     ibs_cpt;        /* CPT id */
};

typedef struct {
        int                     kib_init;       /* initialisation state */
        int                     kib_shutdown;   /* shut down? */
        struct list_head                kib_devs;       /* IB devices extant */
        /* list head of failed devices */
        struct list_head                kib_failed_devs;
        /* schedulers sleep here */
        wait_queue_head_t               kib_failover_waitq;
        atomic_t                kib_nthreads;   /* # live threads */
        /* stabilize net/dev/peer/conn ops */
        rwlock_t                kib_global_lock;
        /* hash table of all my known peers */
        struct list_head                *kib_peers;
        /* size of kib_peers */
        int                     kib_peer_hash_size;
        /* the connd task (serialisation assertions) */
        void                    *kib_connd;
        /* connections to setup/teardown */
        struct list_head                kib_connd_conns;
        /* connections with zero refcount */
        struct list_head                kib_connd_zombies;
        /* connection daemon sleeps here */
        wait_queue_head_t               kib_connd_waitq;
        spinlock_t              kib_connd_lock; /* serialise */
        struct ib_qp_attr       kib_error_qpa;  /* QP->ERROR */
        /* percpt data for schedulers */
        struct kib_sched_info   **kib_scheds;
} kib_data_t;

#define IBLND_INIT_NOTHING       0
#define IBLND_INIT_DATA     1
#define IBLND_INIT_ALL       2

/************************************************************************
 * IB Wire message format.
 * These are sent in sender's byte order (i.e. receiver flips).
 */

typedef struct kib_connparams {
        __u16        ibcp_queue_depth;
        __u16        ibcp_max_frags;
        __u32        ibcp_max_msg_size;
} WIRE_ATTR kib_connparams_t;

typedef struct {
        lnet_hdr_t      ibim_hdr;            /* portals header */
        char          ibim_payload[0];      /* piggy-backed payload */
} WIRE_ATTR kib_immediate_msg_t;

typedef struct {
        __u32        rf_nob;           /* # bytes this frag */
        __u64        rf_addr;         /* CAVEAT EMPTOR: misaligned!! */
} WIRE_ATTR kib_rdma_frag_t;

typedef struct {
        __u32        rd_key;           /* local/remote key */
        __u32        rd_nfrags;     /* # fragments */
        kib_rdma_frag_t   rd_frags[0];    /* buffer frags */
} WIRE_ATTR kib_rdma_desc_t;

typedef struct {
        lnet_hdr_t      ibprm_hdr;          /* portals header */
        __u64        ibprm_cookie;       /* opaque completion cookie */
} WIRE_ATTR kib_putreq_msg_t;

typedef struct {
        __u64        ibpam_src_cookie;     /* reflected completion cookie */
        __u64        ibpam_dst_cookie;     /* opaque completion cookie */
        kib_rdma_desc_t   ibpam_rd;          /* sender's sink buffer */
} WIRE_ATTR kib_putack_msg_t;

typedef struct {
        lnet_hdr_t      ibgm_hdr;            /* portals header */
        __u64        ibgm_cookie;         /* opaque completion cookie */
        kib_rdma_desc_t   ibgm_rd;            /* rdma descriptor */
} WIRE_ATTR kib_get_msg_t;

typedef struct {
        __u64        ibcm_cookie;         /* opaque completion cookie */
        __s32        ibcm_status;         /* < 0 failure: >= 0 length */
} WIRE_ATTR kib_completion_msg_t;

typedef struct {
        /* First 2 fields fixed FOR ALL TIME */
        __u32        ibm_magic;     /* I'm an ibnal message */
        __u16        ibm_version;         /* this is my version number */

        __u8          ibm_type;      /* msg type */
        __u8          ibm_credits;        /* returned credits */
        __u32        ibm_nob;         /* # bytes in whole message */
        __u32        ibm_cksum;     /* checksum (0 == no checksum) */
        __u64        ibm_srcnid;           /* sender's NID */
        __u64        ibm_srcstamp;       /* sender's incarnation */
        __u64        ibm_dstnid;           /* destination's NID */
        __u64        ibm_dststamp;       /* destination's incarnation */

        union {
                kib_connparams_t      connparams;
                kib_immediate_msg_t   immediate;
                kib_putreq_msg_t      putreq;
                kib_putack_msg_t      putack;
                kib_get_msg_t    get;
                kib_completion_msg_t  completion;
        } WIRE_ATTR ibm_u;
} WIRE_ATTR kib_msg_t;

#define IBLND_MSG_MAGIC LNET_PROTO_IB_MAGIC     /* unique magic */

#define IBLND_MSG_VERSION_1      0x11
#define IBLND_MSG_VERSION_2      0x12
#define IBLND_MSG_VERSION          IBLND_MSG_VERSION_2

#define IBLND_MSG_CONNREQ          0xc0 /* connection request */
#define IBLND_MSG_CONNACK          0xc1 /* connection acknowledge */
#define IBLND_MSG_NOOP        0xd0      /* nothing (just credits) */
#define IBLND_MSG_IMMEDIATE      0xd1   /* immediate */
#define IBLND_MSG_PUT_REQ          0xd2 /* putreq (src->sink) */
#define IBLND_MSG_PUT_NAK          0xd3 /* completion (sink->src) */
#define IBLND_MSG_PUT_ACK          0xd4 /* putack (sink->src) */
#define IBLND_MSG_PUT_DONE        0xd5  /* completion (src->sink) */
#define IBLND_MSG_GET_REQ          0xd6 /* getreq (sink->src) */
#define IBLND_MSG_GET_DONE        0xd7  /* completion (src->sink: all OK) */

typedef struct {
        __u32       ibr_magic;       /* sender's magic */
        __u16       ibr_version;           /* sender's version */
        __u8         ibr_why;          /* reject reason */
        __u8         ibr_padding;          /* padding */
        __u64       ibr_incarnation;       /* incarnation of peer */
        kib_connparams_t ibr_cp;                /* connection parameters */
} WIRE_ATTR kib_rej_t;

/* connection rejection reasons */
#define IBLND_REJECT_CONN_RACE       1    /* You lost connection race */
#define IBLND_REJECT_NO_RESOURCES    2    /* Out of memory/conns etc */
#define IBLND_REJECT_FATAL         3      /* Anything else */

#define IBLND_REJECT_CONN_UNCOMPAT   4    /* incompatible version peer */
#define IBLND_REJECT_CONN_STALE      5    /* stale peer */

#define IBLND_REJECT_RDMA_FRAGS      6    /* Fatal: peer's rdma frags can't match mine */
#define IBLND_REJECT_MSG_QUEUE_SIZE  7    /* Fatal: peer's msg queue size can't match mine */

/***********************************************************************/

typedef struct kib_rx                      /* receive message */
{
        struct list_head                rx_list;      /* queue for attention */
        struct kib_conn   *rx_conn;      /* owning conn */
        int                    rx_nob;       /* # bytes received (-1 while posted) */
        enum ib_wc_status        rx_status;    /* completion status */
        kib_msg_t               *rx_msg;       /* message buffer (host vaddr) */
        __u64                rx_msgaddr;   /* message buffer (I/O addr) */
        DECLARE_PCI_UNMAP_ADDR   (rx_msgunmap); /* for dma_unmap_single() */
        struct ib_recv_wr        rx_wrq;       /* receive work item... */
        struct ib_sge        rx_sge;       /* ...and its memory */
} kib_rx_t;

#define IBLND_POSTRX_DONT_POST    0          /* don't post */
#define IBLND_POSTRX_NO_CREDIT    1          /* post: no credits */
#define IBLND_POSTRX_PEER_CREDIT  2          /* post: give peer back 1 credit */
#define IBLND_POSTRX_RSRVD_CREDIT 3          /* post: give myself back 1 reserved credit */

typedef struct kib_tx                      /* transmit message */
{
        struct list_head                tx_list;      /* queue on idle_txs ibc_tx_queue etc. */
        kib_tx_pool_t       *tx_pool;      /* pool I'm from */
        struct kib_conn   *tx_conn;      /* owning conn */
        short                tx_sending;   /* # tx callbacks outstanding */
        short                tx_queued;    /* queued for sending */
        short                tx_waiting;   /* waiting for peer */
        int                    tx_status;    /* LNET completion status */
        unsigned long        tx_deadline;  /* completion deadline */
        __u64                tx_cookie;    /* completion cookie */
        lnet_msg_t             *tx_lntmsg[2]; /* lnet msgs to finalize on completion */
        kib_msg_t               *tx_msg;       /* message buffer (host vaddr) */
        __u64                tx_msgaddr;   /* message buffer (I/O addr) */
        DECLARE_PCI_UNMAP_ADDR   (tx_msgunmap); /* for dma_unmap_single() */
        int                    tx_nwrq;      /* # send work items */
        struct ib_send_wr       *tx_wrq;       /* send work items... */
        struct ib_sge       *tx_sge;       /* ...and their memory */
        kib_rdma_desc_t   *tx_rd;       /* rdma descriptor */
        int                    tx_nfrags;    /* # entries in... */
        struct scatterlist       *tx_frags;     /* dma_map_sg descriptor */
        __u64               *tx_pages;     /* rdma phys page addrs */
        union {
                kib_phys_mr_t      *pmr;        /* MR for physical buffer */
                kib_fmr_t          fmr; /* FMR */
        }                        tx_u;
        int                    tx_dmadir;    /* dma direction */
} kib_tx_t;

typedef struct kib_connvars {
        /* connection-in-progress variables */
        kib_msg_t                cv_msg;
} kib_connvars_t;

typedef struct kib_conn {
        struct kib_sched_info *ibc_sched;       /* scheduler information */
        struct kib_peer     *ibc_peer;    /* owning peer */
        kib_hca_dev_t       *ibc_hdev;    /* HCA bound on */
        struct list_head           ibc_list;      /* stash on peer's conn list */
        struct list_head           ibc_sched_list;    /* schedule for attention */
        __u16           ibc_version;       /* version of connection */
        __u64           ibc_incarnation;   /* which instance of the peer */
        atomic_t         ibc_refcount;      /* # users */
        int               ibc_state;     /* what's happening */
        int               ibc_nsends_posted; /* # uncompleted sends */
        int               ibc_noops_posted;  /* # uncompleted NOOPs */
        int               ibc_credits;       /* # credits I have */
        int               ibc_outstanding_credits; /* # credits to return */
        int               ibc_reserved_credits;/* # ACK/DONE msg credits */
        int               ibc_comms_error;   /* set on comms error */
        unsigned int         ibc_nrx:16;        /* receive buffers owned */
        unsigned int         ibc_scheduled:1;   /* scheduled for attention */
        unsigned int         ibc_ready:1;       /* CQ callback fired */
        /* time of last send */
        unsigned long   ibc_last_send;
        /** link chain for kiblnd_check_conns only */
        struct list_head           ibc_connd_list;
        /** rxs completed before ESTABLISHED */
        struct list_head           ibc_early_rxs;
        /** IBLND_MSG_NOOPs for IBLND_MSG_VERSION_1 */
        struct list_head           ibc_tx_noops;
        struct list_head           ibc_tx_queue;       /* sends that need a credit */
        struct list_head           ibc_tx_queue_nocred;/* sends that don't need a credit */
        struct list_head           ibc_tx_queue_rsrvd; /* sends that need to reserve an ACK/DONE msg */
        struct list_head           ibc_active_txs;     /* active tx awaiting completion */
        spinlock_t           ibc_lock;           /* serialise */
        kib_rx_t            *ibc_rxs;       /* the rx descs */
        kib_pages_t      *ibc_rx_pages;       /* premapped rx msg pages */

        struct rdma_cm_id   *ibc_cmid;     /* CM id */
        struct ib_cq    *ibc_cq;             /* completion queue */

        kib_connvars_t      *ibc_connvars;       /* in-progress connection state */
} kib_conn_t;

#define IBLND_CONN_INIT        0         /* being initialised */
#define IBLND_CONN_ACTIVE_CONNECT     1  /* active sending req */
#define IBLND_CONN_PASSIVE_WAIT       2  /* passive waiting for rtu */
#define IBLND_CONN_ESTABLISHED  3        /* connection established */
#define IBLND_CONN_CLOSING          4    /* being closed */
#define IBLND_CONN_DISCONNECTED       5  /* disconnected */

typedef struct kib_peer {
        struct list_head           ibp_list;       /* stash on global peer list */
        lnet_nid_t         ibp_nid;         /* who's on the other end(s) */
        lnet_ni_t          *ibp_ni;          /* LNet interface */
        atomic_t         ibp_refcount;       /* # users */
        struct list_head           ibp_conns;     /* all active connections */
        struct list_head           ibp_tx_queue;       /* msgs waiting for a conn */
        __u16           ibp_version;    /* version of peer */
        __u64           ibp_incarnation;    /* incarnation of peer */
        int               ibp_connecting;     /* current active connection attempts */
        int               ibp_accepting;      /* current passive connection attempts */
        int               ibp_error;      /* errno on closing this peer */
        unsigned long      ibp_last_alive;     /* when (in jiffies) I was last alive */
} kib_peer_t;

extern kib_data_t      kiblnd_data;

extern void kiblnd_hdev_destroy(kib_hca_dev_t *hdev);

static inline void
kiblnd_hdev_addref_locked(kib_hca_dev_t *hdev)
{
        LASSERT (atomic_read(&hdev->ibh_ref) > 0);
        atomic_inc(&hdev->ibh_ref);
}

static inline void
kiblnd_hdev_decref(kib_hca_dev_t *hdev)
{
        LASSERT (atomic_read(&hdev->ibh_ref) > 0);
        if (atomic_dec_and_test(&hdev->ibh_ref))
                kiblnd_hdev_destroy(hdev);
}

static inline int
kiblnd_dev_can_failover(kib_dev_t *dev)
{
        if (!list_empty(&dev->ibd_fail_list)) /* already scheduled */
                return 0;

        if (*kiblnd_tunables.kib_dev_failover == 0) /* disabled */
                return 0;

        if (*kiblnd_tunables.kib_dev_failover > 1) /* force failover */
                return 1;

        return dev->ibd_can_failover;
}

#define kiblnd_conn_addref(conn)                                \
do {                                                        \
        CDEBUG(D_NET, "conn[%p] (%d)++\n",                    \
               (conn), atomic_read(&(conn)->ibc_refcount)); \
        atomic_inc(&(conn)->ibc_refcount);                \
} while (0)

#define kiblnd_conn_decref(conn)                                        \
do {                                                                    \
        unsigned long flags;                                            \
                                                                        \
        CDEBUG(D_NET, "conn[%p] (%d)--\n",                              \
               (conn), atomic_read(&(conn)->ibc_refcount));             \
        LASSERT_ATOMIC_POS(&(conn)->ibc_refcount);                      \
        if (atomic_dec_and_test(&(conn)->ibc_refcount)) {               \
                spin_lock_irqsave(&kiblnd_data.kib_connd_lock, flags);  \
                list_add_tail(&(conn)->ibc_list,                        \
                                  &kiblnd_data.kib_connd_zombies);      \
                wake_up(&kiblnd_data.kib_connd_waitq);          \
                spin_unlock_irqrestore(&kiblnd_data.kib_connd_lock, flags);\
        }                                                               \
} while (0)

#define kiblnd_peer_addref(peer)                                \
do {                                                        \
        CDEBUG(D_NET, "peer[%p] -> %s (%d)++\n",                \
               (peer), libcfs_nid2str((peer)->ibp_nid),  \
               atomic_read (&(peer)->ibp_refcount));    \
        atomic_inc(&(peer)->ibp_refcount);                \
} while (0)

#define kiblnd_peer_decref(peer)                                \
do {                                                        \
        CDEBUG(D_NET, "peer[%p] -> %s (%d)--\n",                \
               (peer), libcfs_nid2str((peer)->ibp_nid),  \
               atomic_read (&(peer)->ibp_refcount));    \
        LASSERT_ATOMIC_POS(&(peer)->ibp_refcount);            \
        if (atomic_dec_and_test(&(peer)->ibp_refcount))     \
                kiblnd_destroy_peer(peer);                    \
} while (0)

static inline struct list_head *
kiblnd_nid2peerlist (lnet_nid_t nid)
{
        unsigned int hash =
                ((unsigned int)nid) % kiblnd_data.kib_peer_hash_size;

        return (&kiblnd_data.kib_peers [hash]);
}

static inline int
kiblnd_peer_active (kib_peer_t *peer)
{
        /* Am I in the peer hash table? */
        return (!list_empty(&peer->ibp_list));
}

static inline kib_conn_t *
kiblnd_get_conn_locked (kib_peer_t *peer)
{
        LASSERT (!list_empty(&peer->ibp_conns));

        /* just return the first connection */
        return list_entry(peer->ibp_conns.next, kib_conn_t, ibc_list);
}

static inline int
kiblnd_send_keepalive(kib_conn_t *conn)
{
        return (*kiblnd_tunables.kib_keepalive > 0) &&
                cfs_time_after(jiffies, conn->ibc_last_send +
                               *kiblnd_tunables.kib_keepalive*HZ);
}

static inline int
kiblnd_need_noop(kib_conn_t *conn)
{
        LASSERT (conn->ibc_state >= IBLND_CONN_ESTABLISHED);

        if (conn->ibc_outstanding_credits <
            IBLND_CREDITS_HIGHWATER(conn->ibc_version) &&
            !kiblnd_send_keepalive(conn))
                return 0; /* No need to send NOOP */

        if (IBLND_OOB_CAPABLE(conn->ibc_version)) {
                if (!list_empty(&conn->ibc_tx_queue_nocred))
                        return 0; /* NOOP can be piggybacked */

                /* No tx to piggyback NOOP onto or no credit to send a tx */
                return (list_empty(&conn->ibc_tx_queue) ||
                        conn->ibc_credits == 0);
        }

        if (!list_empty(&conn->ibc_tx_noops) || /* NOOP already queued */
            !list_empty(&conn->ibc_tx_queue_nocred) || /* piggyback NOOP */
            conn->ibc_credits == 0)                 /* no credit */
                return 0;

        if (conn->ibc_credits == 1 &&      /* last credit reserved for */
            conn->ibc_outstanding_credits == 0) /* giving back credits */
                return 0;

        /* No tx to piggyback NOOP onto or no credit to send a tx */
        return (list_empty(&conn->ibc_tx_queue) || conn->ibc_credits == 1);
}

static inline void
kiblnd_abort_receives(kib_conn_t *conn)
{
        ib_modify_qp(conn->ibc_cmid->qp,
                     &kiblnd_data.kib_error_qpa, IB_QP_STATE);
}

static inline const char *
kiblnd_queue2str (kib_conn_t *conn, struct list_head *q)
{
        if (q == &conn->ibc_tx_queue)
                return "tx_queue";

        if (q == &conn->ibc_tx_queue_rsrvd)
                return "tx_queue_rsrvd";

        if (q == &conn->ibc_tx_queue_nocred)
                return "tx_queue_nocred";

        if (q == &conn->ibc_active_txs)
                return "active_txs";

        LBUG();
        return NULL;
}

/* CAVEAT EMPTOR: We rely on descriptor alignment to allow us to use the
 * lowest bits of the work request id to stash the work item type. */

#define IBLND_WID_TX    0
#define IBLND_WID_RDMA  1
#define IBLND_WID_RX    2
#define IBLND_WID_MASK  3UL

static inline __u64
kiblnd_ptr2wreqid (void *ptr, int type)
{
        unsigned long lptr = (unsigned long)ptr;

        LASSERT ((lptr & IBLND_WID_MASK) == 0);
        LASSERT ((type & ~IBLND_WID_MASK) == 0);
        return (__u64)(lptr | type);
}

static inline void *
kiblnd_wreqid2ptr (__u64 wreqid)
{
        return (void *)(((unsigned long)wreqid) & ~IBLND_WID_MASK);
}

static inline int
kiblnd_wreqid2type (__u64 wreqid)
{
        return (wreqid & IBLND_WID_MASK);
}

static inline void
kiblnd_set_conn_state (kib_conn_t *conn, int state)
{
        conn->ibc_state = state;
        mb();
}

static inline void
kiblnd_init_msg (kib_msg_t *msg, int type, int body_nob)
{
        msg->ibm_type = type;
        msg->ibm_nob  = offsetof(kib_msg_t, ibm_u) + body_nob;
}

static inline int
kiblnd_rd_size (kib_rdma_desc_t *rd)
{
        int   i;
        int   size;

        for (i = size = 0; i < rd->rd_nfrags; i++)
                size += rd->rd_frags[i].rf_nob;

        return size;
}

static inline __u64
kiblnd_rd_frag_addr(kib_rdma_desc_t *rd, int index)
{
        return rd->rd_frags[index].rf_addr;
}

static inline __u32
kiblnd_rd_frag_size(kib_rdma_desc_t *rd, int index)
{
        return rd->rd_frags[index].rf_nob;
}

static inline __u32
kiblnd_rd_frag_key(kib_rdma_desc_t *rd, int index)
{
        return rd->rd_key;
}

static inline int
kiblnd_rd_consume_frag(kib_rdma_desc_t *rd, int index, __u32 nob)
{
        if (nob < rd->rd_frags[index].rf_nob) {
                rd->rd_frags[index].rf_addr += nob;
                rd->rd_frags[index].rf_nob  -= nob;
        } else {
                index ++;
        }

        return index;
}

static inline int
kiblnd_rd_msg_size(kib_rdma_desc_t *rd, int msgtype, int n)
{
        LASSERT (msgtype == IBLND_MSG_GET_REQ ||
                 msgtype == IBLND_MSG_PUT_ACK);

        return msgtype == IBLND_MSG_GET_REQ ?
               offsetof(kib_get_msg_t, ibgm_rd.rd_frags[n]) :
               offsetof(kib_putack_msg_t, ibpam_rd.rd_frags[n]);
}


static inline __u64
kiblnd_dma_mapping_error(struct ib_device *dev, u64 dma_addr)
{
        return ib_dma_mapping_error(dev, dma_addr);
}

static inline __u64 kiblnd_dma_map_single(struct ib_device *dev,
                                          void *msg, size_t size,
                                          enum dma_data_direction direction)
{
        return ib_dma_map_single(dev, msg, size, direction);
}

static inline void kiblnd_dma_unmap_single(struct ib_device *dev,
                                           __u64 addr, size_t size,
                                          enum dma_data_direction direction)
{
        ib_dma_unmap_single(dev, addr, size, direction);
}

#define KIBLND_UNMAP_ADDR_SET(p, m, a)  do {} while (0)
#define KIBLND_UNMAP_ADDR(p, m, a)      (a)

static inline int kiblnd_dma_map_sg(struct ib_device *dev,
                                    struct scatterlist *sg, int nents,
                                    enum dma_data_direction direction)
{
        return ib_dma_map_sg(dev, sg, nents, direction);
}

static inline void kiblnd_dma_unmap_sg(struct ib_device *dev,
                                       struct scatterlist *sg, int nents,
                                       enum dma_data_direction direction)
{
        ib_dma_unmap_sg(dev, sg, nents, direction);
}

static inline __u64 kiblnd_sg_dma_address(struct ib_device *dev,
                                          struct scatterlist *sg)
{
        return ib_sg_dma_address(dev, sg);
}

static inline unsigned int kiblnd_sg_dma_len(struct ib_device *dev,
                                             struct scatterlist *sg)
{
        return ib_sg_dma_len(dev, sg);
}

/* XXX We use KIBLND_CONN_PARAM(e) as writable buffer, it's not strictly
 * right because OFED1.2 defines it as const, to use it we have to add
 * (void *) cast to overcome "const" */

#define KIBLND_CONN_PARAM(e)        ((e)->param.conn.private_data)
#define KIBLND_CONN_PARAM_LEN(e)        ((e)->param.conn.private_data_len)


struct ib_mr *kiblnd_find_rd_dma_mr(kib_hca_dev_t *hdev,
                                    kib_rdma_desc_t *rd);
struct ib_mr *kiblnd_find_dma_mr(kib_hca_dev_t *hdev,
                                 __u64 addr, __u64 size);
void kiblnd_map_rx_descs(kib_conn_t *conn);
void kiblnd_unmap_rx_descs(kib_conn_t *conn);
int kiblnd_map_tx(lnet_ni_t *ni, kib_tx_t *tx,
                  kib_rdma_desc_t *rd, int nfrags);
void kiblnd_unmap_tx(lnet_ni_t *ni, kib_tx_t *tx);
void kiblnd_pool_free_node(kib_pool_t *pool, struct list_head *node);
struct list_head *kiblnd_pool_alloc_node(kib_poolset_t *ps);

int  kiblnd_fmr_pool_map(kib_fmr_poolset_t *fps, __u64 *pages,
                         int npages, __u64 iov, kib_fmr_t *fmr);
void kiblnd_fmr_pool_unmap(kib_fmr_t *fmr, int status);

int  kiblnd_pmr_pool_map(kib_pmr_poolset_t *pps, kib_hca_dev_t *hdev,
                         kib_rdma_desc_t *rd, __u64 *iova, kib_phys_mr_t **pp_pmr);
void kiblnd_pmr_pool_unmap(kib_phys_mr_t *pmr);

int  kiblnd_startup (lnet_ni_t *ni);
void kiblnd_shutdown (lnet_ni_t *ni);
int  kiblnd_ctl (lnet_ni_t *ni, unsigned int cmd, void *arg);
void kiblnd_query (struct lnet_ni *ni, lnet_nid_t nid, unsigned long *when);

int  kiblnd_tunables_init(void);
void kiblnd_tunables_fini(void);

int  kiblnd_connd (void *arg);
int  kiblnd_scheduler(void *arg);
int  kiblnd_thread_start(int (*fn)(void *arg), void *arg, char *name);
int  kiblnd_failover_thread (void *arg);

int  kiblnd_alloc_pages(kib_pages_t **pp, int cpt, int npages);
void kiblnd_free_pages (kib_pages_t *p);

int  kiblnd_cm_callback(struct rdma_cm_id *cmid,
                        struct rdma_cm_event *event);
int  kiblnd_translate_mtu(int value);

int  kiblnd_dev_failover(kib_dev_t *dev);
int  kiblnd_create_peer (lnet_ni_t *ni, kib_peer_t **peerp, lnet_nid_t nid);
void kiblnd_destroy_peer (kib_peer_t *peer);
void kiblnd_destroy_dev (kib_dev_t *dev);
void kiblnd_unlink_peer_locked (kib_peer_t *peer);
void kiblnd_peer_alive (kib_peer_t *peer);
kib_peer_t *kiblnd_find_peer_locked (lnet_nid_t nid);
void kiblnd_peer_connect_failed (kib_peer_t *peer, int active, int error);
int  kiblnd_close_stale_conns_locked (kib_peer_t *peer,
                                      int version, __u64 incarnation);
int  kiblnd_close_peer_conns_locked (kib_peer_t *peer, int why);

void kiblnd_connreq_done(kib_conn_t *conn, int status);

kib_conn_t *kiblnd_create_conn (kib_peer_t *peer, struct rdma_cm_id *cmid,
                                int state, int version);
void kiblnd_destroy_conn (kib_conn_t *conn);
void kiblnd_close_conn (kib_conn_t *conn, int error);
void kiblnd_close_conn_locked (kib_conn_t *conn, int error);

int  kiblnd_init_rdma (kib_conn_t *conn, kib_tx_t *tx, int type,
                       int nob, kib_rdma_desc_t *dstrd, __u64 dstcookie);

void kiblnd_launch_tx (lnet_ni_t *ni, kib_tx_t *tx, lnet_nid_t nid);
void kiblnd_queue_tx_locked (kib_tx_t *tx, kib_conn_t *conn);
void kiblnd_queue_tx (kib_tx_t *tx, kib_conn_t *conn);
void kiblnd_init_tx_msg (lnet_ni_t *ni, kib_tx_t *tx, int type, int body_nob);
void kiblnd_txlist_done (lnet_ni_t *ni, struct list_head *txlist,
                         int status);
void kiblnd_check_sends (kib_conn_t *conn);

void kiblnd_qp_event(struct ib_event *event, void *arg);
void kiblnd_cq_event(struct ib_event *event, void *arg);
void kiblnd_cq_completion(struct ib_cq *cq, void *arg);

void kiblnd_pack_msg (lnet_ni_t *ni, kib_msg_t *msg, int version,
                      int credits, lnet_nid_t dstnid, __u64 dststamp);
int  kiblnd_unpack_msg(kib_msg_t *msg, int nob);
int  kiblnd_post_rx (kib_rx_t *rx, int credit);

int  kiblnd_send(lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg);
int  kiblnd_recv(lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg, int delayed,
                 unsigned int niov, struct iovec *iov, lnet_kiov_t *kiov,
                 unsigned int offset, unsigned int mlen, unsigned int rlen);