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[tomato.git] / release / src-rt-6.x.4708 / linux / linux-2.6.36 / drivers / scsi / cxgb3i / cxgb3i_offload.c

/*
 * cxgb3i_offload.c: Chelsio S3xx iscsi offloaded tcp connection management
 *
 * Copyright (C) 2003-2008 Chelsio Communications.  All rights reserved.
 *
 * 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 LICENSE file included in this
 * release for licensing terms and conditions.
 *
 * Written by:  Dimitris Michailidis (dm@chelsio.com)
 *              Karen Xie (kxie@chelsio.com)
 */

#include <linux/if_vlan.h>
#include <linux/slab.h>
#include <linux/version.h>

#include "cxgb3_defs.h"
#include "cxgb3_ctl_defs.h"
#include "firmware_exports.h"
#include "cxgb3i_offload.h"
#include "cxgb3i_pdu.h"
#include "cxgb3i_ddp.h"

#ifdef __DEBUG_C3CN_CONN__
#define c3cn_conn_debug         cxgb3i_log_debug
#else
#define c3cn_conn_debug(fmt...)
#endif

#ifdef __DEBUG_C3CN_TX__
#define c3cn_tx_debug           cxgb3i_log_debug
#else
#define c3cn_tx_debug(fmt...)
#endif

#ifdef __DEBUG_C3CN_RX__
#define c3cn_rx_debug           cxgb3i_log_debug
#else
#define c3cn_rx_debug(fmt...)
#endif

/*
 * module parameters releated to offloaded iscsi connection
 */
static int cxgb3_rcv_win = 256 * 1024;
module_param(cxgb3_rcv_win, int, 0644);
MODULE_PARM_DESC(cxgb3_rcv_win, "TCP receive window in bytes (default=256KB)");

static int cxgb3_snd_win = 128 * 1024;
module_param(cxgb3_snd_win, int, 0644);
MODULE_PARM_DESC(cxgb3_snd_win, "TCP send window in bytes (default=128KB)");

static int cxgb3_rx_credit_thres = 10 * 1024;
module_param(cxgb3_rx_credit_thres, int, 0644);
MODULE_PARM_DESC(rx_credit_thres,
                 "RX credits return threshold in bytes (default=10KB)");

static unsigned int cxgb3_max_connect = 8 * 1024;
module_param(cxgb3_max_connect, uint, 0644);
MODULE_PARM_DESC(cxgb3_max_connect, "Max. # of connections (default=8092)");

static unsigned int cxgb3_sport_base = 20000;
module_param(cxgb3_sport_base, uint, 0644);
MODULE_PARM_DESC(cxgb3_sport_base, "starting port number (default=20000)");

/*
 * cxgb3i tcp connection data(per adapter) list
 */
static LIST_HEAD(cdata_list);
static DEFINE_RWLOCK(cdata_rwlock);

static int c3cn_push_tx_frames(struct s3_conn *c3cn, int req_completion);
static void c3cn_release_offload_resources(struct s3_conn *c3cn);

/*
 * iscsi source port management
 *
 * Find a free source port in the port allocation map. We use a very simple
 * rotor scheme to look for the next free port.
 *
 * If a source port has been specified make sure that it doesn't collide with
 * our normal source port allocation map.  If it's outside the range of our
 * allocation/deallocation scheme just let them use it.
 *
 * If the source port is outside our allocation range, the caller is
 * responsible for keeping track of their port usage.
 */
static int c3cn_get_port(struct s3_conn *c3cn, struct cxgb3i_sdev_data *cdata)
{
        unsigned int start;
        int idx;

        if (!cdata)
                goto error_out;

        if (c3cn->saddr.sin_port) {
                cxgb3i_log_error("connect, sin_port NON-ZERO %u.\n",
                                 c3cn->saddr.sin_port);
                return -EADDRINUSE;
        }

        spin_lock_bh(&cdata->lock);
        start = idx = cdata->sport_next;
        do {
                if (++idx >= cxgb3_max_connect)
                        idx = 0;
                if (!cdata->sport_conn[idx]) {
                        c3cn->saddr.sin_port = htons(cxgb3_sport_base + idx);
                        cdata->sport_next = idx;
                        cdata->sport_conn[idx] = c3cn;
                        spin_unlock_bh(&cdata->lock);

                        c3cn_conn_debug("%s reserve port %u.\n",
                                        cdata->cdev->name,
                                        cxgb3_sport_base + idx);
                        return 0;
                }
        } while (idx != start);
        spin_unlock_bh(&cdata->lock);

error_out:
        return -EADDRNOTAVAIL;
}

static void c3cn_put_port(struct s3_conn *c3cn)
{
        if (!c3cn->cdev)
                return;

        if (c3cn->saddr.sin_port) {
                struct cxgb3i_sdev_data *cdata = CXGB3_SDEV_DATA(c3cn->cdev);
                int idx = ntohs(c3cn->saddr.sin_port) - cxgb3_sport_base;

                c3cn->saddr.sin_port = 0;
                if (idx < 0 || idx >= cxgb3_max_connect)
                        return;
                spin_lock_bh(&cdata->lock);
                cdata->sport_conn[idx] = NULL;
                spin_unlock_bh(&cdata->lock);
                c3cn_conn_debug("%s, release port %u.\n",
                                cdata->cdev->name, cxgb3_sport_base + idx);
        }
}

static inline void c3cn_set_flag(struct s3_conn *c3cn, enum c3cn_flags flag)
{
        __set_bit(flag, &c3cn->flags);
        c3cn_conn_debug("c3cn 0x%p, set %d, s %u, f 0x%lx.\n",
                        c3cn, flag, c3cn->state, c3cn->flags);
}

static inline void c3cn_clear_flag(struct s3_conn *c3cn, enum c3cn_flags flag)
{
        __clear_bit(flag, &c3cn->flags);
        c3cn_conn_debug("c3cn 0x%p, clear %d, s %u, f 0x%lx.\n",
                        c3cn, flag, c3cn->state, c3cn->flags);
}

static inline int c3cn_flag(struct s3_conn *c3cn, enum c3cn_flags flag)
{
        if (c3cn == NULL)
                return 0;
        return test_bit(flag, &c3cn->flags);
}

static void c3cn_set_state(struct s3_conn *c3cn, int state)
{
        c3cn_conn_debug("c3cn 0x%p state -> %u.\n", c3cn, state);
        c3cn->state = state;
}

static inline void c3cn_hold(struct s3_conn *c3cn)
{
        atomic_inc(&c3cn->refcnt);
}

static inline void c3cn_put(struct s3_conn *c3cn)
{
        if (atomic_dec_and_test(&c3cn->refcnt)) {
                c3cn_conn_debug("free c3cn 0x%p, s %u, f 0x%lx.\n",
                                c3cn, c3cn->state, c3cn->flags);
                kfree(c3cn);
        }
}

static void c3cn_closed(struct s3_conn *c3cn)
{
        c3cn_conn_debug("c3cn 0x%p, state %u, flag 0x%lx.\n",
                         c3cn, c3cn->state, c3cn->flags);

        c3cn_put_port(c3cn);
        c3cn_release_offload_resources(c3cn);
        c3cn_set_state(c3cn, C3CN_STATE_CLOSED);
        cxgb3i_conn_closing(c3cn);
}

/*
 * CPL (Chelsio Protocol Language) defines a message passing interface between
 * the host driver and T3 asic.
 * The section below implments CPLs that related to iscsi tcp connection
 * open/close/abort and data send/receive.
 */

/*
 * CPL connection active open request: host ->
 */
static unsigned int find_best_mtu(const struct t3c_data *d, unsigned short mtu)
{
        int i = 0;

        while (i < d->nmtus - 1 && d->mtus[i + 1] <= mtu)
                ++i;
        return i;
}

static unsigned int select_mss(struct s3_conn *c3cn, unsigned int pmtu)
{
        unsigned int idx;
        struct dst_entry *dst = c3cn->dst_cache;
        struct t3cdev *cdev = c3cn->cdev;
        const struct t3c_data *td = T3C_DATA(cdev);
        u16 advmss = dst_metric(dst, RTAX_ADVMSS);

        if (advmss > pmtu - 40)
                advmss = pmtu - 40;
        if (advmss < td->mtus[0] - 40)
                advmss = td->mtus[0] - 40;
        idx = find_best_mtu(td, advmss + 40);
        return idx;
}

static inline int compute_wscale(int win)
{
        int wscale = 0;
        while (wscale < 14 && (65535<<wscale) < win)
                wscale++;
        return wscale;
}

static inline unsigned int calc_opt0h(struct s3_conn *c3cn)
{
        int wscale = compute_wscale(cxgb3_rcv_win);
        return  V_KEEP_ALIVE(1) |
                F_TCAM_BYPASS |
                V_WND_SCALE(wscale) |
                V_MSS_IDX(c3cn->mss_idx);
}

static inline unsigned int calc_opt0l(struct s3_conn *c3cn)
{
        return  V_ULP_MODE(ULP_MODE_ISCSI) |
                V_RCV_BUFSIZ(cxgb3_rcv_win>>10);
}

static void make_act_open_req(struct s3_conn *c3cn, struct sk_buff *skb,
                              unsigned int atid, const struct l2t_entry *e)
{
        struct cpl_act_open_req *req;

        c3cn_conn_debug("c3cn 0x%p, atid 0x%x.\n", c3cn, atid);

        skb->priority = CPL_PRIORITY_SETUP;
        req = (struct cpl_act_open_req *)__skb_put(skb, sizeof(*req));
        req->wr.wr_hi = htonl(V_WR_OP(FW_WROPCODE_FORWARD));
        req->wr.wr_lo = 0;
        OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_ACT_OPEN_REQ, atid));
        req->local_port = c3cn->saddr.sin_port;
        req->peer_port = c3cn->daddr.sin_port;
        req->local_ip = c3cn->saddr.sin_addr.s_addr;
        req->peer_ip = c3cn->daddr.sin_addr.s_addr;
        req->opt0h = htonl(calc_opt0h(c3cn) | V_L2T_IDX(e->idx) |
                           V_TX_CHANNEL(e->smt_idx));
        req->opt0l = htonl(calc_opt0l(c3cn));
        req->params = 0;
        req->opt2 = 0;
}

static void fail_act_open(struct s3_conn *c3cn, int errno)
{
        c3cn_conn_debug("c3cn 0x%p, state %u, flag 0x%lx.\n",
                        c3cn, c3cn->state, c3cn->flags);
        c3cn->err = errno;
        c3cn_closed(c3cn);
}

static void act_open_req_arp_failure(struct t3cdev *dev, struct sk_buff *skb)
{
        struct s3_conn *c3cn = (struct s3_conn *)skb->sk;

        c3cn_conn_debug("c3cn 0x%p, state %u.\n", c3cn, c3cn->state);

        c3cn_hold(c3cn);
        spin_lock_bh(&c3cn->lock);
        if (c3cn->state == C3CN_STATE_CONNECTING)
                fail_act_open(c3cn, -EHOSTUNREACH);
        spin_unlock_bh(&c3cn->lock);
        c3cn_put(c3cn);
        __kfree_skb(skb);
}

/*
 * CPL connection close request: host ->
 *
 * Close a connection by sending a CPL_CLOSE_CON_REQ message and queue it to
 * the write queue (i.e., after any unsent txt data).
 */
static void skb_entail(struct s3_conn *c3cn, struct sk_buff *skb,
                       int flags)
{
        skb_tcp_seq(skb) = c3cn->write_seq;
        skb_flags(skb) = flags;
        __skb_queue_tail(&c3cn->write_queue, skb);
}

static void send_close_req(struct s3_conn *c3cn)
{
        struct sk_buff *skb = c3cn->cpl_close;
        struct cpl_close_con_req *req = (struct cpl_close_con_req *)skb->head;
        unsigned int tid = c3cn->tid;

        c3cn_conn_debug("c3cn 0x%p, state 0x%x, flag 0x%lx.\n",
                        c3cn, c3cn->state, c3cn->flags);

        c3cn->cpl_close = NULL;

        req->wr.wr_hi = htonl(V_WR_OP(FW_WROPCODE_OFLD_CLOSE_CON));
        req->wr.wr_lo = htonl(V_WR_TID(tid));
        OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_CLOSE_CON_REQ, tid));
        req->rsvd = htonl(c3cn->write_seq);

        skb_entail(c3cn, skb, C3CB_FLAG_NO_APPEND);
        if (c3cn->state != C3CN_STATE_CONNECTING)
                c3cn_push_tx_frames(c3cn, 1);
}

/*
 * CPL connection abort request: host ->
 *
 * Send an ABORT_REQ message. Makes sure we do not send multiple ABORT_REQs
 * for the same connection and also that we do not try to send a message
 * after the connection has closed.
 */
static void abort_arp_failure(struct t3cdev *cdev, struct sk_buff *skb)
{
        struct cpl_abort_req *req = cplhdr(skb);

        c3cn_conn_debug("tdev 0x%p.\n", cdev);

        req->cmd = CPL_ABORT_NO_RST;
        cxgb3_ofld_send(cdev, skb);
}

static inline void c3cn_purge_write_queue(struct s3_conn *c3cn)
{
        struct sk_buff *skb;

        while ((skb = __skb_dequeue(&c3cn->write_queue)))
                __kfree_skb(skb);
}

static void send_abort_req(struct s3_conn *c3cn)
{
        struct sk_buff *skb = c3cn->cpl_abort_req;
        struct cpl_abort_req *req;
        unsigned int tid = c3cn->tid;

        if (unlikely(c3cn->state == C3CN_STATE_ABORTING) || !skb ||
                     !c3cn->cdev)
                return;

        c3cn_set_state(c3cn, C3CN_STATE_ABORTING);

        c3cn_conn_debug("c3cn 0x%p, flag ABORT_RPL + ABORT_SHUT.\n", c3cn);

        c3cn_set_flag(c3cn, C3CN_ABORT_RPL_PENDING);

        /* Purge the send queue so we don't send anything after an abort. */
        c3cn_purge_write_queue(c3cn);

        c3cn->cpl_abort_req = NULL;
        req = (struct cpl_abort_req *)skb->head;
        memset(req, 0, sizeof(*req));

        skb->priority = CPL_PRIORITY_DATA;
        set_arp_failure_handler(skb, abort_arp_failure);

        req->wr.wr_hi = htonl(V_WR_OP(FW_WROPCODE_OFLD_HOST_ABORT_CON_REQ));
        req->wr.wr_lo = htonl(V_WR_TID(tid));
        OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_ABORT_REQ, tid));
        req->rsvd0 = htonl(c3cn->snd_nxt);
        req->rsvd1 = !c3cn_flag(c3cn, C3CN_TX_DATA_SENT);
        req->cmd = CPL_ABORT_SEND_RST;

        l2t_send(c3cn->cdev, skb, c3cn->l2t);
}

/*
 * CPL connection abort reply: host ->
 *
 * Send an ABORT_RPL message in response of the ABORT_REQ received.
 */
static void send_abort_rpl(struct s3_conn *c3cn, int rst_status)
{
        struct sk_buff *skb = c3cn->cpl_abort_rpl;
        struct cpl_abort_rpl *rpl = (struct cpl_abort_rpl *)skb->head;

        c3cn->cpl_abort_rpl = NULL;

        skb->priority = CPL_PRIORITY_DATA;
        memset(rpl, 0, sizeof(*rpl));
        rpl->wr.wr_hi = htonl(V_WR_OP(FW_WROPCODE_OFLD_HOST_ABORT_CON_RPL));
        rpl->wr.wr_lo = htonl(V_WR_TID(c3cn->tid));
        OPCODE_TID(rpl) = htonl(MK_OPCODE_TID(CPL_ABORT_RPL, c3cn->tid));
        rpl->cmd = rst_status;

        cxgb3_ofld_send(c3cn->cdev, skb);
}

/*
 * CPL connection rx data ack: host ->
 * Send RX credits through an RX_DATA_ACK CPL message. Returns the number of
 * credits sent.
 */
static u32 send_rx_credits(struct s3_conn *c3cn, u32 credits, u32 dack)
{
        struct sk_buff *skb;
        struct cpl_rx_data_ack *req;

        skb = alloc_skb(sizeof(*req), GFP_ATOMIC);
        if (!skb)
                return 0;

        req = (struct cpl_rx_data_ack *)__skb_put(skb, sizeof(*req));
        req->wr.wr_hi = htonl(V_WR_OP(FW_WROPCODE_FORWARD));
        req->wr.wr_lo = 0;
        OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_RX_DATA_ACK, c3cn->tid));
        req->credit_dack = htonl(dack | V_RX_CREDITS(credits));
        skb->priority = CPL_PRIORITY_ACK;
        cxgb3_ofld_send(c3cn->cdev, skb);
        return credits;
}

/*
 * CPL connection tx data: host ->
 *
 * Send iscsi PDU via TX_DATA CPL message. Returns the number of
 * credits sent.
 * Each TX_DATA consumes work request credit (wrs), so we need to keep track of
 * how many we've used so far and how many are pending (i.e., yet ack'ed by T3).
 */

/*
 * For ULP connections HW may inserts digest bytes into the pdu. Those digest
 * bytes are not sent by the host but are part of the TCP payload and therefore
 * consume TCP sequence space.
 */
static const unsigned int cxgb3_ulp_extra_len[] = { 0, 4, 4, 8 };
static inline unsigned int ulp_extra_len(const struct sk_buff *skb)
{
        return cxgb3_ulp_extra_len[skb_ulp_mode(skb) & 3];
}

static unsigned int wrlen __read_mostly;

/*
 * The number of WRs needed for an skb depends on the number of fragments
 * in the skb and whether it has any payload in its main body.  This maps the
 * length of the gather list represented by an skb into the # of necessary WRs.
 * The extra two fragments are for iscsi bhs and payload padding.
 */
#define SKB_WR_LIST_SIZE        (MAX_SKB_FRAGS + 2)
static unsigned int skb_wrs[SKB_WR_LIST_SIZE] __read_mostly;

static void s3_init_wr_tab(unsigned int wr_len)
{
        int i;

        if (skb_wrs[1])         /* already initialized */
                return;

        for (i = 1; i < SKB_WR_LIST_SIZE; i++) {
                int sgl_len = (3 * i) / 2 + (i & 1);

                sgl_len += 3;
                skb_wrs[i] = (sgl_len <= wr_len
                              ? 1 : 1 + (sgl_len - 2) / (wr_len - 1));
        }

        wrlen = wr_len * 8;
}

static inline void reset_wr_list(struct s3_conn *c3cn)
{
        c3cn->wr_pending_head = c3cn->wr_pending_tail = NULL;
}

/*
 * Add a WR to a connections's list of pending WRs.  This is a singly-linked
 * list of sk_buffs operating as a FIFO.  The head is kept in wr_pending_head
 * and the tail in wr_pending_tail.
 */
static inline void enqueue_wr(struct s3_conn *c3cn,
                              struct sk_buff *skb)
{
        skb_tx_wr_next(skb) = NULL;

        /*
         * We want to take an extra reference since both us and the driver
         * need to free the packet before it's really freed. We know there's
         * just one user currently so we use atomic_set rather than skb_get
         * to avoid the atomic op.
         */
        atomic_set(&skb->users, 2);

        if (!c3cn->wr_pending_head)
                c3cn->wr_pending_head = skb;
        else
                skb_tx_wr_next(c3cn->wr_pending_tail) = skb;
        c3cn->wr_pending_tail = skb;
}

static int count_pending_wrs(struct s3_conn *c3cn)
{
        int n = 0;
        const struct sk_buff *skb = c3cn->wr_pending_head;

        while (skb) {
                n += skb->csum;
                skb = skb_tx_wr_next(skb);
        }
        return n;
}

static inline struct sk_buff *peek_wr(const struct s3_conn *c3cn)
{
        return c3cn->wr_pending_head;
}

static inline void free_wr_skb(struct sk_buff *skb)
{
        kfree_skb(skb);
}

static inline struct sk_buff *dequeue_wr(struct s3_conn *c3cn)
{
        struct sk_buff *skb = c3cn->wr_pending_head;

        if (likely(skb)) {
                /* Don't bother clearing the tail */
                c3cn->wr_pending_head = skb_tx_wr_next(skb);
                skb_tx_wr_next(skb) = NULL;
        }
        return skb;
}

static void purge_wr_queue(struct s3_conn *c3cn)
{
        struct sk_buff *skb;
        while ((skb = dequeue_wr(c3cn)) != NULL)
                free_wr_skb(skb);
}

static inline void make_tx_data_wr(struct s3_conn *c3cn, struct sk_buff *skb,
                                   int len, int req_completion)
{
        struct tx_data_wr *req;

        skb_reset_transport_header(skb);
        req = (struct tx_data_wr *)__skb_push(skb, sizeof(*req));
        req->wr_hi = htonl(V_WR_OP(FW_WROPCODE_OFLD_TX_DATA) |
                        (req_completion ? F_WR_COMPL : 0));
        req->wr_lo = htonl(V_WR_TID(c3cn->tid));
        req->sndseq = htonl(c3cn->snd_nxt);
        /* len includes the length of any HW ULP additions */
        req->len = htonl(len);
        req->param = htonl(V_TX_PORT(c3cn->l2t->smt_idx));
        /* V_TX_ULP_SUBMODE sets both the mode and submode */
        req->flags = htonl(V_TX_ULP_SUBMODE(skb_ulp_mode(skb)) |
                           V_TX_SHOVE((skb_peek(&c3cn->write_queue) ? 0 : 1)));

        if (!c3cn_flag(c3cn, C3CN_TX_DATA_SENT)) {
                req->flags |= htonl(V_TX_ACK_PAGES(2) | F_TX_INIT |
                                    V_TX_CPU_IDX(c3cn->qset));
                /* Sendbuffer is in units of 32KB. */
                req->param |= htonl(V_TX_SNDBUF(cxgb3_snd_win >> 15));
                c3cn_set_flag(c3cn, C3CN_TX_DATA_SENT);
        }
}

/**
 * c3cn_push_tx_frames -- start transmit
 * @c3cn: the offloaded connection
 * @req_completion: request wr_ack or not
 *
 * Prepends TX_DATA_WR or CPL_CLOSE_CON_REQ headers to buffers waiting in a
 * connection's send queue and sends them on to T3.  Must be called with the
 * connection's lock held.  Returns the amount of send buffer space that was
 * freed as a result of sending queued data to T3.
 */
static void arp_failure_discard(struct t3cdev *cdev, struct sk_buff *skb)
{
        kfree_skb(skb);
}

static int c3cn_push_tx_frames(struct s3_conn *c3cn, int req_completion)
{
        int total_size = 0;
        struct sk_buff *skb;
        struct t3cdev *cdev;
        struct cxgb3i_sdev_data *cdata;

        if (unlikely(c3cn->state == C3CN_STATE_CONNECTING ||
                     c3cn->state == C3CN_STATE_CLOSE_WAIT_1 ||
                     c3cn->state >= C3CN_STATE_ABORTING)) {
                c3cn_tx_debug("c3cn 0x%p, in closing state %u.\n",
                              c3cn, c3cn->state);
                return 0;
        }

        cdev = c3cn->cdev;
        cdata = CXGB3_SDEV_DATA(cdev);

        while (c3cn->wr_avail
               && (skb = skb_peek(&c3cn->write_queue)) != NULL) {
                int len = skb->len;     /* length before skb_push */
                int frags = skb_shinfo(skb)->nr_frags + (len != skb->data_len);
                int wrs_needed = skb_wrs[frags];

                if (wrs_needed > 1 && len + sizeof(struct tx_data_wr) <= wrlen)
                        wrs_needed = 1;

                WARN_ON(frags >= SKB_WR_LIST_SIZE || wrs_needed < 1);

                if (c3cn->wr_avail < wrs_needed) {
                        c3cn_tx_debug("c3cn 0x%p, skb len %u/%u, frag %u, "
                                      "wr %d < %u.\n",
                                      c3cn, skb->len, skb->data_len, frags,
                                      wrs_needed, c3cn->wr_avail);
                        break;
                }

                __skb_unlink(skb, &c3cn->write_queue);
                skb->priority = CPL_PRIORITY_DATA;
                skb->csum = wrs_needed; /* remember this until the WR_ACK */
                c3cn->wr_avail -= wrs_needed;
                c3cn->wr_unacked += wrs_needed;
                enqueue_wr(c3cn, skb);

                c3cn_tx_debug("c3cn 0x%p, enqueue, skb len %u/%u, frag %u, "
                                "wr %d, left %u, unack %u.\n",
                                c3cn, skb->len, skb->data_len, frags,
                                wrs_needed, c3cn->wr_avail, c3cn->wr_unacked);


                if (likely(skb_flags(skb) & C3CB_FLAG_NEED_HDR)) {
                        if ((req_completion &&
                                c3cn->wr_unacked == wrs_needed) ||
                            (skb_flags(skb) & C3CB_FLAG_COMPL) ||
                            c3cn->wr_unacked >= c3cn->wr_max / 2) {
                                req_completion = 1;
                                c3cn->wr_unacked = 0;
                        }
                        len += ulp_extra_len(skb);
                        make_tx_data_wr(c3cn, skb, len, req_completion);
                        c3cn->snd_nxt += len;
                        skb_flags(skb) &= ~C3CB_FLAG_NEED_HDR;
                }

                total_size += skb->truesize;
                set_arp_failure_handler(skb, arp_failure_discard);
                l2t_send(cdev, skb, c3cn->l2t);
        }
        return total_size;
}

/*
 * process_cpl_msg: -> host
 * Top-level CPL message processing used by most CPL messages that
 * pertain to connections.
 */
static inline void process_cpl_msg(void (*fn)(struct s3_conn *,
                                              struct sk_buff *),
                                   struct s3_conn *c3cn,
                                   struct sk_buff *skb)
{
        spin_lock_bh(&c3cn->lock);
        fn(c3cn, skb);
        spin_unlock_bh(&c3cn->lock);
}

/*
 * process_cpl_msg_ref: -> host
 * Similar to process_cpl_msg() but takes an extra connection reference around
 * the call to the handler.  Should be used if the handler may drop a
 * connection reference.
 */
static inline void process_cpl_msg_ref(void (*fn) (struct s3_conn *,
                                                   struct sk_buff *),
                                       struct s3_conn *c3cn,
                                       struct sk_buff *skb)
{
        c3cn_hold(c3cn);
        process_cpl_msg(fn, c3cn, skb);
        c3cn_put(c3cn);
}

/*
 * Process a CPL_ACT_ESTABLISH message: -> host
 * Updates connection state from an active establish CPL message.  Runs with
 * the connection lock held.
 */

static inline void s3_free_atid(struct t3cdev *cdev, unsigned int tid)
{
        struct s3_conn *c3cn = cxgb3_free_atid(cdev, tid);
        if (c3cn)
                c3cn_put(c3cn);
}

static void c3cn_established(struct s3_conn *c3cn, u32 snd_isn,
                             unsigned int opt)
{
        c3cn_conn_debug("c3cn 0x%p, state %u.\n", c3cn, c3cn->state);

        c3cn->write_seq = c3cn->snd_nxt = c3cn->snd_una = snd_isn;

        /*
         * Causes the first RX_DATA_ACK to supply any Rx credits we couldn't
         * pass through opt0.
         */
        if (cxgb3_rcv_win > (M_RCV_BUFSIZ << 10))
                c3cn->rcv_wup -= cxgb3_rcv_win - (M_RCV_BUFSIZ << 10);

        dst_confirm(c3cn->dst_cache);

        smp_mb();

        c3cn_set_state(c3cn, C3CN_STATE_ESTABLISHED);
}

static void process_act_establish(struct s3_conn *c3cn, struct sk_buff *skb)
{
        struct cpl_act_establish *req = cplhdr(skb);
        u32 rcv_isn = ntohl(req->rcv_isn);      /* real RCV_ISN + 1 */

        c3cn_conn_debug("c3cn 0x%p, state %u, flag 0x%lx.\n",
                        c3cn, c3cn->state, c3cn->flags);

        if (unlikely(c3cn->state != C3CN_STATE_CONNECTING))
                cxgb3i_log_error("TID %u expected SYN_SENT, got EST., s %u\n",
                                 c3cn->tid, c3cn->state);

        c3cn->copied_seq = c3cn->rcv_wup = c3cn->rcv_nxt = rcv_isn;
        c3cn_established(c3cn, ntohl(req->snd_isn), ntohs(req->tcp_opt));

        __kfree_skb(skb);

        if (unlikely(c3cn_flag(c3cn, C3CN_ACTIVE_CLOSE_NEEDED)))
                /* upper layer has requested closing */
                send_abort_req(c3cn);
        else {
                if (skb_queue_len(&c3cn->write_queue))
                        c3cn_push_tx_frames(c3cn, 1);
                cxgb3i_conn_tx_open(c3cn);
        }
}

static int do_act_establish(struct t3cdev *cdev, struct sk_buff *skb,
                            void *ctx)
{
        struct cpl_act_establish *req = cplhdr(skb);
        unsigned int tid = GET_TID(req);
        unsigned int atid = G_PASS_OPEN_TID(ntohl(req->tos_tid));
        struct s3_conn *c3cn = ctx;
        struct cxgb3i_sdev_data *cdata = CXGB3_SDEV_DATA(cdev);

        c3cn_conn_debug("rcv, tid 0x%x, c3cn 0x%p, s %u, f 0x%lx.\n",
                        tid, c3cn, c3cn->state, c3cn->flags);

        c3cn->tid = tid;
        c3cn_hold(c3cn);
        cxgb3_insert_tid(cdata->cdev, cdata->client, c3cn, tid);
        s3_free_atid(cdev, atid);

        c3cn->qset = G_QNUM(ntohl(skb->csum));

        process_cpl_msg(process_act_establish, c3cn, skb);
        return 0;
}

/*
 * Process a CPL_ACT_OPEN_RPL message: -> host
 * Handle active open failures.
 */
static int act_open_rpl_status_to_errno(int status)
{
        switch (status) {
        case CPL_ERR_CONN_RESET:
                return -ECONNREFUSED;
        case CPL_ERR_ARP_MISS:
                return -EHOSTUNREACH;
        case CPL_ERR_CONN_TIMEDOUT:
                return -ETIMEDOUT;
        case CPL_ERR_TCAM_FULL:
                return -ENOMEM;
        case CPL_ERR_CONN_EXIST:
                cxgb3i_log_error("ACTIVE_OPEN_RPL: 4-tuple in use\n");
                return -EADDRINUSE;
        default:
                return -EIO;
        }
}

static void act_open_retry_timer(unsigned long data)
{
        struct sk_buff *skb;
        struct s3_conn *c3cn = (struct s3_conn *)data;

        c3cn_conn_debug("c3cn 0x%p, state %u.\n", c3cn, c3cn->state);

        spin_lock_bh(&c3cn->lock);
        skb = alloc_skb(sizeof(struct cpl_act_open_req), GFP_ATOMIC);
        if (!skb)
                fail_act_open(c3cn, -ENOMEM);
        else {
                skb->sk = (struct sock *)c3cn;
                set_arp_failure_handler(skb, act_open_req_arp_failure);
                make_act_open_req(c3cn, skb, c3cn->tid, c3cn->l2t);
                l2t_send(c3cn->cdev, skb, c3cn->l2t);
        }
        spin_unlock_bh(&c3cn->lock);
        c3cn_put(c3cn);
}

static void process_act_open_rpl(struct s3_conn *c3cn, struct sk_buff *skb)
{
        struct cpl_act_open_rpl *rpl = cplhdr(skb);

        c3cn_conn_debug("c3cn 0x%p, state %u, flag 0x%lx.\n",
                        c3cn, c3cn->state, c3cn->flags);

        if (rpl->status == CPL_ERR_CONN_EXIST &&
            c3cn->retry_timer.function != act_open_retry_timer) {
                c3cn->retry_timer.function = act_open_retry_timer;
                if (!mod_timer(&c3cn->retry_timer, jiffies + HZ / 2))
                        c3cn_hold(c3cn);
        } else
                fail_act_open(c3cn, act_open_rpl_status_to_errno(rpl->status));
        __kfree_skb(skb);
}

static int do_act_open_rpl(struct t3cdev *cdev, struct sk_buff *skb, void *ctx)
{
        struct s3_conn *c3cn = ctx;
        struct cpl_act_open_rpl *rpl = cplhdr(skb);

        c3cn_conn_debug("rcv, status 0x%x, c3cn 0x%p, s %u, f 0x%lx.\n",
                        rpl->status, c3cn, c3cn->state, c3cn->flags);

        if (rpl->status != CPL_ERR_TCAM_FULL &&
            rpl->status != CPL_ERR_CONN_EXIST &&
            rpl->status != CPL_ERR_ARP_MISS)
                cxgb3_queue_tid_release(cdev, GET_TID(rpl));

        process_cpl_msg_ref(process_act_open_rpl, c3cn, skb);
        return 0;
}

/*
 * Process PEER_CLOSE CPL messages: -> host
 * Handle peer FIN.
 */
static void process_peer_close(struct s3_conn *c3cn, struct sk_buff *skb)
{
        c3cn_conn_debug("c3cn 0x%p, state %u, flag 0x%lx.\n",
                        c3cn, c3cn->state, c3cn->flags);

        if (c3cn_flag(c3cn, C3CN_ABORT_RPL_PENDING))
                goto out;

        switch (c3cn->state) {
        case C3CN_STATE_ESTABLISHED:
                c3cn_set_state(c3cn, C3CN_STATE_PASSIVE_CLOSE);
                break;
        case C3CN_STATE_ACTIVE_CLOSE:
                c3cn_set_state(c3cn, C3CN_STATE_CLOSE_WAIT_2);
                break;
        case C3CN_STATE_CLOSE_WAIT_1:
                c3cn_closed(c3cn);
                break;
        case C3CN_STATE_ABORTING:
                break;
        default:
                cxgb3i_log_error("%s: peer close, TID %u in bad state %u\n",
                                 c3cn->cdev->name, c3cn->tid, c3cn->state);
        }

        cxgb3i_conn_closing(c3cn);
out:
        __kfree_skb(skb);
}

static int do_peer_close(struct t3cdev *cdev, struct sk_buff *skb, void *ctx)
{
        struct s3_conn *c3cn = ctx;

        c3cn_conn_debug("rcv, c3cn 0x%p, s %u, f 0x%lx.\n",
                        c3cn, c3cn->state, c3cn->flags);
        process_cpl_msg_ref(process_peer_close, c3cn, skb);
        return 0;
}

/*
 * Process CLOSE_CONN_RPL CPL message: -> host
 * Process a peer ACK to our FIN.
 */
static void process_close_con_rpl(struct s3_conn *c3cn, struct sk_buff *skb)
{
        struct cpl_close_con_rpl *rpl = cplhdr(skb);

        c3cn_conn_debug("c3cn 0x%p, state %u, flag 0x%lx.\n",
                        c3cn, c3cn->state, c3cn->flags);

        c3cn->snd_una = ntohl(rpl->snd_nxt) - 1;        /* exclude FIN */

        if (c3cn_flag(c3cn, C3CN_ABORT_RPL_PENDING))
                goto out;

        switch (c3cn->state) {
        case C3CN_STATE_ACTIVE_CLOSE:
                c3cn_set_state(c3cn, C3CN_STATE_CLOSE_WAIT_1);
                break;
        case C3CN_STATE_CLOSE_WAIT_1:
        case C3CN_STATE_CLOSE_WAIT_2:
                c3cn_closed(c3cn);
                break;
        case C3CN_STATE_ABORTING:
                break;
        default:
                cxgb3i_log_error("%s: close_rpl, TID %u in bad state %u\n",
                                 c3cn->cdev->name, c3cn->tid, c3cn->state);
        }

out:
        kfree_skb(skb);
}

static int do_close_con_rpl(struct t3cdev *cdev, struct sk_buff *skb,
                            void *ctx)
{
        struct s3_conn *c3cn = ctx;

        c3cn_conn_debug("rcv, c3cn 0x%p, s %u, f 0x%lx.\n",
                         c3cn, c3cn->state, c3cn->flags);

        process_cpl_msg_ref(process_close_con_rpl, c3cn, skb);
        return 0;
}

/*
 * Process ABORT_REQ_RSS CPL message: -> host
 * Process abort requests.  If we are waiting for an ABORT_RPL we ignore this
 * request except that we need to reply to it.
 */

static int abort_status_to_errno(struct s3_conn *c3cn, int abort_reason,
                                 int *need_rst)
{
        switch (abort_reason) {
        case CPL_ERR_BAD_SYN: /* fall through */
        case CPL_ERR_CONN_RESET:
                return c3cn->state > C3CN_STATE_ESTABLISHED ?
                        -EPIPE : -ECONNRESET;
        case CPL_ERR_XMIT_TIMEDOUT:
        case CPL_ERR_PERSIST_TIMEDOUT:
        case CPL_ERR_FINWAIT2_TIMEDOUT:
        case CPL_ERR_KEEPALIVE_TIMEDOUT:
                return -ETIMEDOUT;
        default:
                return -EIO;
        }
}

static void process_abort_req(struct s3_conn *c3cn, struct sk_buff *skb)
{
        int rst_status = CPL_ABORT_NO_RST;
        const struct cpl_abort_req_rss *req = cplhdr(skb);

        c3cn_conn_debug("c3cn 0x%p, state %u, flag 0x%lx.\n",
                        c3cn, c3cn->state, c3cn->flags);

        if (!c3cn_flag(c3cn, C3CN_ABORT_REQ_RCVD)) {
                c3cn_set_flag(c3cn, C3CN_ABORT_REQ_RCVD);
                c3cn_set_state(c3cn, C3CN_STATE_ABORTING);
                __kfree_skb(skb);
                return;
        }

        c3cn_clear_flag(c3cn, C3CN_ABORT_REQ_RCVD);
        send_abort_rpl(c3cn, rst_status);

        if (!c3cn_flag(c3cn, C3CN_ABORT_RPL_PENDING)) {
                c3cn->err =
                    abort_status_to_errno(c3cn, req->status, &rst_status);
                c3cn_closed(c3cn);
        }
}

static int do_abort_req(struct t3cdev *cdev, struct sk_buff *skb, void *ctx)
{
        const struct cpl_abort_req_rss *req = cplhdr(skb);
        struct s3_conn *c3cn = ctx;

        c3cn_conn_debug("rcv, c3cn 0x%p, s 0x%x, f 0x%lx.\n",
                        c3cn, c3cn->state, c3cn->flags);

        if (req->status == CPL_ERR_RTX_NEG_ADVICE ||
            req->status == CPL_ERR_PERSIST_NEG_ADVICE) {
                __kfree_skb(skb);
                return 0;
        }

        process_cpl_msg_ref(process_abort_req, c3cn, skb);
        return 0;
}

/*
 * Process ABORT_RPL_RSS CPL message: -> host
 * Process abort replies.  We only process these messages if we anticipate
 * them as the coordination between SW and HW in this area is somewhat lacking
 * and sometimes we get ABORT_RPLs after we are done with the connection that
 * originated the ABORT_REQ.
 */
static void process_abort_rpl(struct s3_conn *c3cn, struct sk_buff *skb)
{
        c3cn_conn_debug("c3cn 0x%p, state %u, flag 0x%lx.\n",
                        c3cn, c3cn->state, c3cn->flags);

        if (c3cn_flag(c3cn, C3CN_ABORT_RPL_PENDING)) {
                if (!c3cn_flag(c3cn, C3CN_ABORT_RPL_RCVD))
                        c3cn_set_flag(c3cn, C3CN_ABORT_RPL_RCVD);
                else {
                        c3cn_clear_flag(c3cn, C3CN_ABORT_RPL_RCVD);
                        c3cn_clear_flag(c3cn, C3CN_ABORT_RPL_PENDING);
                        if (c3cn_flag(c3cn, C3CN_ABORT_REQ_RCVD))
                                cxgb3i_log_error("%s tid %u, ABORT_RPL_RSS\n",
                                                 c3cn->cdev->name, c3cn->tid);
                        c3cn_closed(c3cn);
                }
        }
        __kfree_skb(skb);
}

static int do_abort_rpl(struct t3cdev *cdev, struct sk_buff *skb, void *ctx)
{
        struct cpl_abort_rpl_rss *rpl = cplhdr(skb);
        struct s3_conn *c3cn = ctx;

        c3cn_conn_debug("rcv, status 0x%x, c3cn 0x%p, s %u, 0x%lx.\n",
                        rpl->status, c3cn, c3cn ? c3cn->state : 0,
                        c3cn ? c3cn->flags : 0UL);

        /*
         * Ignore replies to post-close aborts indicating that the abort was
         * requested too late.  These connections are terminated when we get
         * PEER_CLOSE or CLOSE_CON_RPL and by the time the abort_rpl_rss
         * arrives the TID is either no longer used or it has been recycled.
         */
        if (rpl->status == CPL_ERR_ABORT_FAILED)
                goto discard;

        /*
         * Sometimes we've already closed the connection, e.g., a post-close
         * abort races with ABORT_REQ_RSS, the latter frees the connection
         * expecting the ABORT_REQ will fail with CPL_ERR_ABORT_FAILED,
         * but FW turns the ABORT_REQ into a regular one and so we get
         * ABORT_RPL_RSS with status 0 and no connection.
         */
        if (!c3cn)
                goto discard;

        process_cpl_msg_ref(process_abort_rpl, c3cn, skb);
        return 0;

discard:
        __kfree_skb(skb);
        return 0;
}

/*
 * Process RX_ISCSI_HDR CPL message: -> host
 * Handle received PDUs, the payload could be DDP'ed. If not, the payload
 * follow after the bhs.
 */
static void process_rx_iscsi_hdr(struct s3_conn *c3cn, struct sk_buff *skb)
{
        struct cpl_iscsi_hdr *hdr_cpl = cplhdr(skb);
        struct cpl_iscsi_hdr_norss data_cpl;
        struct cpl_rx_data_ddp_norss ddp_cpl;
        unsigned int hdr_len, data_len, status;
        unsigned int len;
        int err;

        if (unlikely(c3cn->state >= C3CN_STATE_PASSIVE_CLOSE)) {
                if (c3cn->state != C3CN_STATE_ABORTING)
                        send_abort_req(c3cn);
                __kfree_skb(skb);
                return;
        }

        skb_tcp_seq(skb) = ntohl(hdr_cpl->seq);
        skb_flags(skb) = 0;

        skb_reset_transport_header(skb);
        __skb_pull(skb, sizeof(struct cpl_iscsi_hdr));

        len = hdr_len = ntohs(hdr_cpl->len);
        /* msg coalesce is off or not enough data received */
        if (skb->len <= hdr_len) {
                cxgb3i_log_error("%s: TID %u, ISCSI_HDR, skb len %u < %u.\n",
                                 c3cn->cdev->name, c3cn->tid,
                                 skb->len, hdr_len);
                goto abort_conn;
        }

        err = skb_copy_bits(skb, skb->len - sizeof(ddp_cpl), &ddp_cpl,
                            sizeof(ddp_cpl));
        if (err < 0)
                goto abort_conn;

        skb_ulp_mode(skb) = ULP2_FLAG_DATA_READY;
        skb_rx_pdulen(skb) = ntohs(ddp_cpl.len);
        skb_rx_ddigest(skb) = ntohl(ddp_cpl.ulp_crc);
        status = ntohl(ddp_cpl.ddp_status);

        c3cn_rx_debug("rx skb 0x%p, len %u, pdulen %u, ddp status 0x%x.\n",
                      skb, skb->len, skb_rx_pdulen(skb), status);

        if (status & (1 << RX_DDP_STATUS_HCRC_SHIFT))
                skb_ulp_mode(skb) |= ULP2_FLAG_HCRC_ERROR;
        if (status & (1 << RX_DDP_STATUS_DCRC_SHIFT))
                skb_ulp_mode(skb) |= ULP2_FLAG_DCRC_ERROR;
        if (status & (1 << RX_DDP_STATUS_PAD_SHIFT))
                skb_ulp_mode(skb) |= ULP2_FLAG_PAD_ERROR;

        if (skb->len > (hdr_len + sizeof(ddp_cpl))) {
                err = skb_copy_bits(skb, hdr_len, &data_cpl, sizeof(data_cpl));
                if (err < 0)
                        goto abort_conn;
                data_len = ntohs(data_cpl.len);
                len += sizeof(data_cpl) + data_len;
        } else if (status & (1 << RX_DDP_STATUS_DDP_SHIFT))
                skb_ulp_mode(skb) |= ULP2_FLAG_DATA_DDPED;

        c3cn->rcv_nxt = ntohl(ddp_cpl.seq) + skb_rx_pdulen(skb);
        __pskb_trim(skb, len);
        __skb_queue_tail(&c3cn->receive_queue, skb);
        cxgb3i_conn_pdu_ready(c3cn);

        return;

abort_conn:
        send_abort_req(c3cn);
        __kfree_skb(skb);
}

static int do_iscsi_hdr(struct t3cdev *t3dev, struct sk_buff *skb, void *ctx)
{
        struct s3_conn *c3cn = ctx;

        process_cpl_msg(process_rx_iscsi_hdr, c3cn, skb);
        return 0;
}

/*
 * Process TX_DATA_ACK CPL messages: -> host
 * Process an acknowledgment of WR completion.  Advance snd_una and send the
 * next batch of work requests from the write queue.
 */
static void check_wr_invariants(struct s3_conn *c3cn)
{
        int pending = count_pending_wrs(c3cn);

        if (unlikely(c3cn->wr_avail + pending != c3cn->wr_max))
                cxgb3i_log_error("TID %u: credit imbalance: avail %u, "
                                "pending %u, total should be %u\n",
                                c3cn->tid, c3cn->wr_avail, pending,
                                c3cn->wr_max);
}

static void process_wr_ack(struct s3_conn *c3cn, struct sk_buff *skb)
{
        struct cpl_wr_ack *hdr = cplhdr(skb);
        unsigned int credits = ntohs(hdr->credits);
        u32 snd_una = ntohl(hdr->snd_una);

        c3cn_tx_debug("%u WR credits, avail %u, unack %u, TID %u, state %u.\n",
                        credits, c3cn->wr_avail, c3cn->wr_unacked,
                        c3cn->tid, c3cn->state);

        c3cn->wr_avail += credits;
        if (c3cn->wr_unacked > c3cn->wr_max - c3cn->wr_avail)
                c3cn->wr_unacked = c3cn->wr_max - c3cn->wr_avail;

        while (credits) {
                struct sk_buff *p = peek_wr(c3cn);

                if (unlikely(!p)) {
                        cxgb3i_log_error("%u WR_ACK credits for TID %u with "
                                         "nothing pending, state %u\n",
                                         credits, c3cn->tid, c3cn->state);
                        break;
                }
                if (unlikely(credits < p->csum)) {
                        struct tx_data_wr *w = cplhdr(p);
                        cxgb3i_log_error("TID %u got %u WR credits need %u, "
                                         "len %u, main body %u, frags %u, "
                                         "seq # %u, ACK una %u, ACK nxt %u, "
                                         "WR_AVAIL %u, WRs pending %u\n",
                                         c3cn->tid, credits, p->csum, p->len,
                                         p->len - p->data_len,
                                         skb_shinfo(p)->nr_frags,
                                         ntohl(w->sndseq), snd_una,
                                         ntohl(hdr->snd_nxt), c3cn->wr_avail,
                                         count_pending_wrs(c3cn) - credits);
                        p->csum -= credits;
                        break;
                } else {
                        dequeue_wr(c3cn);
                        credits -= p->csum;
                        free_wr_skb(p);
                }
        }

        check_wr_invariants(c3cn);

        if (unlikely(before(snd_una, c3cn->snd_una))) {
                cxgb3i_log_error("TID %u, unexpected sequence # %u in WR_ACK "
                                 "snd_una %u\n",
                                 c3cn->tid, snd_una, c3cn->snd_una);
                goto out_free;
        }

        if (c3cn->snd_una != snd_una) {
                c3cn->snd_una = snd_una;
                dst_confirm(c3cn->dst_cache);
        }

        if (skb_queue_len(&c3cn->write_queue)) {
                if (c3cn_push_tx_frames(c3cn, 0))
                        cxgb3i_conn_tx_open(c3cn);
        } else
                cxgb3i_conn_tx_open(c3cn);
out_free:
        __kfree_skb(skb);
}

static int do_wr_ack(struct t3cdev *cdev, struct sk_buff *skb, void *ctx)
{
        struct s3_conn *c3cn = ctx;

        process_cpl_msg(process_wr_ack, c3cn, skb);
        return 0;
}

/*
 * for each connection, pre-allocate skbs needed for close/abort requests. So
 * that we can service the request right away.
 */
static void c3cn_free_cpl_skbs(struct s3_conn *c3cn)
{
        if (c3cn->cpl_close)
                kfree_skb(c3cn->cpl_close);
        if (c3cn->cpl_abort_req)
                kfree_skb(c3cn->cpl_abort_req);
        if (c3cn->cpl_abort_rpl)
                kfree_skb(c3cn->cpl_abort_rpl);
}

static int c3cn_alloc_cpl_skbs(struct s3_conn *c3cn)
{
        c3cn->cpl_close = alloc_skb(sizeof(struct cpl_close_con_req),
                                   GFP_KERNEL);
        if (!c3cn->cpl_close)
                return -ENOMEM;
        skb_put(c3cn->cpl_close, sizeof(struct cpl_close_con_req));

        c3cn->cpl_abort_req = alloc_skb(sizeof(struct cpl_abort_req),
                                        GFP_KERNEL);
        if (!c3cn->cpl_abort_req)
                goto free_cpl_skbs;
        skb_put(c3cn->cpl_abort_req, sizeof(struct cpl_abort_req));

        c3cn->cpl_abort_rpl = alloc_skb(sizeof(struct cpl_abort_rpl),
                                        GFP_KERNEL);
        if (!c3cn->cpl_abort_rpl)
                goto free_cpl_skbs;
        skb_put(c3cn->cpl_abort_rpl, sizeof(struct cpl_abort_rpl));

        return 0;

free_cpl_skbs:
        c3cn_free_cpl_skbs(c3cn);
        return -ENOMEM;
}

/**
 * c3cn_release_offload_resources - release offload resource
 * @c3cn: the offloaded iscsi tcp connection.
 * Release resources held by an offload connection (TID, L2T entry, etc.)
 */
static void c3cn_release_offload_resources(struct s3_conn *c3cn)
{
        struct t3cdev *cdev = c3cn->cdev;
        unsigned int tid = c3cn->tid;

        c3cn->qset = 0;
        c3cn_free_cpl_skbs(c3cn);

        if (c3cn->wr_avail != c3cn->wr_max) {
                purge_wr_queue(c3cn);
                reset_wr_list(c3cn);
        }

        if (cdev) {
                if (c3cn->l2t) {
                        l2t_release(L2DATA(cdev), c3cn->l2t);
                        c3cn->l2t = NULL;
                }
                if (c3cn->state == C3CN_STATE_CONNECTING)
                        /* we have ATID */
                        s3_free_atid(cdev, tid);
                else {
                        /* we have TID */
                        cxgb3_remove_tid(cdev, (void *)c3cn, tid);
                        c3cn_put(c3cn);
                }
        }

        c3cn->dst_cache = NULL;
        c3cn->cdev = NULL;
}

/**
 * cxgb3i_c3cn_create - allocate and initialize an s3_conn structure
 * returns the s3_conn structure allocated.
 */
struct s3_conn *cxgb3i_c3cn_create(void)
{
        struct s3_conn *c3cn;

        c3cn = kzalloc(sizeof(*c3cn), GFP_KERNEL);
        if (!c3cn)
                return NULL;

        /* pre-allocate close/abort cpl, so we don't need to wait for memory
           when close/abort is requested. */
        if (c3cn_alloc_cpl_skbs(c3cn) < 0)
                goto free_c3cn;

        c3cn_conn_debug("alloc c3cn 0x%p.\n", c3cn);

        c3cn->flags = 0;
        spin_lock_init(&c3cn->lock);
        atomic_set(&c3cn->refcnt, 1);
        skb_queue_head_init(&c3cn->receive_queue);
        skb_queue_head_init(&c3cn->write_queue);
        setup_timer(&c3cn->retry_timer, NULL, (unsigned long)c3cn);
        rwlock_init(&c3cn->callback_lock);

        return c3cn;

free_c3cn:
        kfree(c3cn);
        return NULL;
}

static void c3cn_active_close(struct s3_conn *c3cn)
{
        int data_lost;
        int close_req = 0;

        c3cn_conn_debug("c3cn 0x%p, state %u, flag 0x%lx.\n",
                         c3cn, c3cn->state, c3cn->flags);

        dst_confirm(c3cn->dst_cache);

        c3cn_hold(c3cn);
        spin_lock_bh(&c3cn->lock);

        data_lost = skb_queue_len(&c3cn->receive_queue);
        __skb_queue_purge(&c3cn->receive_queue);

        switch (c3cn->state) {
        case C3CN_STATE_CLOSED:
        case C3CN_STATE_ACTIVE_CLOSE:
        case C3CN_STATE_CLOSE_WAIT_1:
        case C3CN_STATE_CLOSE_WAIT_2:
        case C3CN_STATE_ABORTING:
                /* nothing need to be done */
                break;
        case C3CN_STATE_CONNECTING:
                /* defer until cpl_act_open_rpl or cpl_act_establish */
                c3cn_set_flag(c3cn, C3CN_ACTIVE_CLOSE_NEEDED);
                break;
        case C3CN_STATE_ESTABLISHED:
                close_req = 1;
                c3cn_set_state(c3cn, C3CN_STATE_ACTIVE_CLOSE);
                break;
        case C3CN_STATE_PASSIVE_CLOSE:
                close_req = 1;
                c3cn_set_state(c3cn, C3CN_STATE_CLOSE_WAIT_2);
                break;
        }

        if (close_req) {
                if (data_lost)
                        /* Unread data was tossed, zap the connection. */
                        send_abort_req(c3cn);
                else
                        send_close_req(c3cn);
        }

        spin_unlock_bh(&c3cn->lock);
        c3cn_put(c3cn);
}

/**
 * cxgb3i_c3cn_release - close and release an iscsi tcp connection and any
 *      resource held
 * @c3cn: the iscsi tcp connection
 */
void cxgb3i_c3cn_release(struct s3_conn *c3cn)
{
        c3cn_conn_debug("c3cn 0x%p, s %u, f 0x%lx.\n",
                        c3cn, c3cn->state, c3cn->flags);
        if (unlikely(c3cn->state == C3CN_STATE_CONNECTING))
                c3cn_set_flag(c3cn, C3CN_ACTIVE_CLOSE_NEEDED);
        else if (likely(c3cn->state != C3CN_STATE_CLOSED))
                c3cn_active_close(c3cn);
        c3cn_put(c3cn);
}

static int is_cxgb3_dev(struct net_device *dev)
{
        struct cxgb3i_sdev_data *cdata;
        struct net_device *ndev = dev;

        if (dev->priv_flags & IFF_802_1Q_VLAN)
                ndev = vlan_dev_real_dev(dev);

        write_lock(&cdata_rwlock);
        list_for_each_entry(cdata, &cdata_list, list) {
                struct adap_ports *ports = &cdata->ports;
                int i;

                for (i = 0; i < ports->nports; i++)
                        if (ndev == ports->lldevs[i]) {
                                write_unlock(&cdata_rwlock);
                                return 1;
                        }
        }
        write_unlock(&cdata_rwlock);
        return 0;
}

/**
 * cxgb3_egress_dev - return the cxgb3 egress device
 * @root_dev: the root device anchoring the search
 * @c3cn: the connection used to determine egress port in bonding mode
 * @context: in bonding mode, indicates a connection set up or failover
 *
 * Return egress device or NULL if the egress device isn't one of our ports.
 */
static struct net_device *cxgb3_egress_dev(struct net_device *root_dev,
                                           struct s3_conn *c3cn,
                                           int context)
{
        while (root_dev) {
                if (root_dev->priv_flags & IFF_802_1Q_VLAN)
                        root_dev = vlan_dev_real_dev(root_dev);
                else if (is_cxgb3_dev(root_dev))
                        return root_dev;
                else
                        return NULL;
        }
        return NULL;
}

static struct rtable *find_route(struct net_device *dev,
                                 __be32 saddr, __be32 daddr,
                                 __be16 sport, __be16 dport)
{
        struct rtable *rt;
        struct flowi fl = {
                .oif = dev ? dev->ifindex : 0,
                .nl_u = {
                         .ip4_u = {
                                   .daddr = daddr,
                                   .saddr = saddr,
                                   .tos = 0 } },
                .proto = IPPROTO_TCP,
                .uli_u = {
                          .ports = {
                                    .sport = sport,
                                    .dport = dport } } };

        if (ip_route_output_flow(&init_net, &rt, &fl, NULL, 0))
                return NULL;
        return rt;
}

/*
 * Assign offload parameters to some connection fields.
 */
static void init_offload_conn(struct s3_conn *c3cn,
                              struct t3cdev *cdev,
                              struct dst_entry *dst)
{
        BUG_ON(c3cn->cdev != cdev);
        c3cn->wr_max = c3cn->wr_avail = T3C_DATA(cdev)->max_wrs - 1;
        c3cn->wr_unacked = 0;
        c3cn->mss_idx = select_mss(c3cn, dst_mtu(dst));

        reset_wr_list(c3cn);
}

static int initiate_act_open(struct s3_conn *c3cn, struct net_device *dev)
{
        struct cxgb3i_sdev_data *cdata = NDEV2CDATA(dev);
        struct t3cdev *cdev = cdata->cdev;
        struct dst_entry *dst = c3cn->dst_cache;
        struct sk_buff *skb;

        c3cn_conn_debug("c3cn 0x%p, state %u, flag 0x%lx.\n",
                        c3cn, c3cn->state, c3cn->flags);
        /*
         * Initialize connection data.  Note that the flags and ULP mode are
         * initialized higher up ...
         */
        c3cn->dev = dev;
        c3cn->cdev = cdev;
        c3cn->tid = cxgb3_alloc_atid(cdev, cdata->client, c3cn);
        if (c3cn->tid < 0)
                goto out_err;

        c3cn->qset = 0;
        c3cn->l2t = t3_l2t_get(cdev, dst->neighbour, dev);
        if (!c3cn->l2t)
                goto free_tid;

        skb = alloc_skb(sizeof(struct cpl_act_open_req), GFP_KERNEL);
        if (!skb)
                goto free_l2t;

        skb->sk = (struct sock *)c3cn;
        set_arp_failure_handler(skb, act_open_req_arp_failure);

        c3cn_hold(c3cn);

        init_offload_conn(c3cn, cdev, dst);
        c3cn->err = 0;

        make_act_open_req(c3cn, skb, c3cn->tid, c3cn->l2t);
        l2t_send(cdev, skb, c3cn->l2t);
        return 0;

free_l2t:
        l2t_release(L2DATA(cdev), c3cn->l2t);
free_tid:
        s3_free_atid(cdev, c3cn->tid);
        c3cn->tid = 0;
out_err:
        return -EINVAL;
}

/**
 * cxgb3i_find_dev - find the interface associated with the given address
 * @ipaddr: ip address
 */
static struct net_device *
cxgb3i_find_dev(struct net_device *dev, __be32 ipaddr)
{
        struct flowi fl;
        int err;
        struct rtable *rt;

        memset(&fl, 0, sizeof(fl));
        fl.nl_u.ip4_u.daddr = ipaddr;

        err = ip_route_output_key(dev ? dev_net(dev) : &init_net, &rt, &fl);
        if (!err)
                return (&rt->dst)->dev;

        return NULL;
}

/**
 * cxgb3i_c3cn_connect - initiates an iscsi tcp connection to a given address
 * @c3cn: the iscsi tcp connection
 * @usin: destination address
 *
 * return 0 if active open request is sent, < 0 otherwise.
 */
int cxgb3i_c3cn_connect(struct net_device *dev, struct s3_conn *c3cn,
                        struct sockaddr_in *usin)
{
        struct rtable *rt;
        struct cxgb3i_sdev_data *cdata;
        struct t3cdev *cdev;
        __be32 sipv4;
        struct net_device *dstdev;
        int err;

        c3cn_conn_debug("c3cn 0x%p, dev 0x%p.\n", c3cn, dev);

        if (usin->sin_family != AF_INET)
                return -EAFNOSUPPORT;

        c3cn->daddr.sin_port = usin->sin_port;
        c3cn->daddr.sin_addr.s_addr = usin->sin_addr.s_addr;

        dstdev = cxgb3i_find_dev(dev, usin->sin_addr.s_addr);
        if (!dstdev || !is_cxgb3_dev(dstdev))
                return -ENETUNREACH;

        if (dstdev->priv_flags & IFF_802_1Q_VLAN)
                dev = dstdev;

        rt = find_route(dev, c3cn->saddr.sin_addr.s_addr,
                        c3cn->daddr.sin_addr.s_addr,
                        c3cn->saddr.sin_port,
                        c3cn->daddr.sin_port);
        if (rt == NULL) {
                c3cn_conn_debug("NO route to 0x%x, port %u, dev %s.\n",
                                c3cn->daddr.sin_addr.s_addr,
                                ntohs(c3cn->daddr.sin_port),
                                dev ? dev->name : "any");
                return -ENETUNREACH;
        }

        if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
                c3cn_conn_debug("multi-cast route to 0x%x, port %u, dev %s.\n",
                                c3cn->daddr.sin_addr.s_addr,
                                ntohs(c3cn->daddr.sin_port),
                                dev ? dev->name : "any");
                ip_rt_put(rt);
                return -ENETUNREACH;
        }

        if (!c3cn->saddr.sin_addr.s_addr)
                c3cn->saddr.sin_addr.s_addr = rt->rt_src;

        /* now commit destination to connection */
        c3cn->dst_cache = &rt->dst;

        /* try to establish an offloaded connection */
        dev = cxgb3_egress_dev(c3cn->dst_cache->dev, c3cn, 0);
        if (dev == NULL) {
                c3cn_conn_debug("c3cn 0x%p, egress dev NULL.\n", c3cn);
                return -ENETUNREACH;
        }
        cdata = NDEV2CDATA(dev);
        cdev = cdata->cdev;

        /* get a source port if one hasn't been provided */
        err = c3cn_get_port(c3cn, cdata);
        if (err)
                return err;

        c3cn_conn_debug("c3cn 0x%p get port %u.\n",
                        c3cn, ntohs(c3cn->saddr.sin_port));

        sipv4 = cxgb3i_get_private_ipv4addr(dev);
        if (!sipv4) {
                c3cn_conn_debug("c3cn 0x%p, iscsi ip not configured.\n", c3cn);
                sipv4 = c3cn->saddr.sin_addr.s_addr;
                cxgb3i_set_private_ipv4addr(dev, sipv4);
        } else
                c3cn->saddr.sin_addr.s_addr = sipv4;

        c3cn_conn_debug("c3cn 0x%p, %pI4,%u-%pI4,%u SYN_SENT.\n",
                        c3cn,
                        &c3cn->saddr.sin_addr.s_addr,
                        ntohs(c3cn->saddr.sin_port),
                        &c3cn->daddr.sin_addr.s_addr,
                        ntohs(c3cn->daddr.sin_port));

        c3cn_set_state(c3cn, C3CN_STATE_CONNECTING);
        if (!initiate_act_open(c3cn, dev))
                return 0;

        /*
         * If we get here, we don't have an offload connection so simply
         * return a failure.
         */
        err = -ENOTSUPP;

        /*
         * This trashes the connection and releases the local port,
         * if necessary.
         */
        c3cn_conn_debug("c3cn 0x%p -> CLOSED.\n", c3cn);
        c3cn_set_state(c3cn, C3CN_STATE_CLOSED);
        ip_rt_put(rt);
        c3cn_put_port(c3cn);
        return err;
}

/**
 * cxgb3i_c3cn_rx_credits - ack received tcp data.
 * @c3cn: iscsi tcp connection
 * @copied: # of bytes processed
 *
 * Called after some received data has been read.  It returns RX credits
 * to the HW for the amount of data processed.
 */
void cxgb3i_c3cn_rx_credits(struct s3_conn *c3cn, int copied)
{
        struct t3cdev *cdev;
        int must_send;
        u32 credits, dack = 0;

        if (c3cn->state != C3CN_STATE_ESTABLISHED)
                return;

        credits = c3cn->copied_seq - c3cn->rcv_wup;
        if (unlikely(!credits))
                return;

        cdev = c3cn->cdev;

        if (unlikely(cxgb3_rx_credit_thres == 0))
                return;

        dack = F_RX_DACK_CHANGE | V_RX_DACK_MODE(1);

        /*
         * For coalescing to work effectively ensure the receive window has
         * at least 16KB left.
         */
        must_send = credits + 16384 >= cxgb3_rcv_win;

        if (must_send || credits >= cxgb3_rx_credit_thres)
                c3cn->rcv_wup += send_rx_credits(c3cn, credits, dack);
}

/**
 * cxgb3i_c3cn_send_pdus - send the skbs containing iscsi pdus
 * @c3cn: iscsi tcp connection
 * @skb: skb contains the iscsi pdu
 *
 * Add a list of skbs to a connection send queue. The skbs must comply with
 * the max size limit of the device and have a headroom of at least
 * TX_HEADER_LEN bytes.
 * Return # of bytes queued.
 */
int cxgb3i_c3cn_send_pdus(struct s3_conn *c3cn, struct sk_buff *skb)
{
        struct sk_buff *next;
        int err, copied = 0;

        spin_lock_bh(&c3cn->lock);

        if (c3cn->state != C3CN_STATE_ESTABLISHED) {
                c3cn_tx_debug("c3cn 0x%p, not in est. state %u.\n",
                              c3cn, c3cn->state);
                err = -EAGAIN;
                goto out_err;
        }

        if (c3cn->err) {
                c3cn_tx_debug("c3cn 0x%p, err %d.\n", c3cn, c3cn->err);
                err = -EPIPE;
                goto out_err;
        }

        if (c3cn->write_seq - c3cn->snd_una >= cxgb3_snd_win) {
                c3cn_tx_debug("c3cn 0x%p, snd %u - %u > %u.\n",
                                c3cn, c3cn->write_seq, c3cn->snd_una,
                                cxgb3_snd_win);
                err = -ENOBUFS;
                goto out_err;
        }

        while (skb) {
                int frags = skb_shinfo(skb)->nr_frags +
                                (skb->len != skb->data_len);

                if (unlikely(skb_headroom(skb) < TX_HEADER_LEN)) {
                        c3cn_tx_debug("c3cn 0x%p, skb head.\n", c3cn);
                        err = -EINVAL;
                        goto out_err;
                }

                if (frags >= SKB_WR_LIST_SIZE) {
                        cxgb3i_log_error("c3cn 0x%p, tx frags %d, len %u,%u.\n",
                                         c3cn, skb_shinfo(skb)->nr_frags,
                                         skb->len, skb->data_len);
                        err = -EINVAL;
                        goto out_err;
                }

                next = skb->next;
                skb->next = NULL;
                skb_entail(c3cn, skb, C3CB_FLAG_NO_APPEND | C3CB_FLAG_NEED_HDR);
                copied += skb->len;
                c3cn->write_seq += skb->len + ulp_extra_len(skb);
                skb = next;
        }
done:
        if (likely(skb_queue_len(&c3cn->write_queue)))
                c3cn_push_tx_frames(c3cn, 1);
        spin_unlock_bh(&c3cn->lock);
        return copied;

out_err:
        if (copied == 0 && err == -EPIPE)
                copied = c3cn->err ? c3cn->err : -EPIPE;
        else
                copied = err;
        goto done;
}

static void sdev_data_cleanup(struct cxgb3i_sdev_data *cdata)
{
        struct adap_ports *ports = &cdata->ports;
        struct s3_conn *c3cn;
        int i;

        for (i = 0; i < cxgb3_max_connect; i++) {
                if (cdata->sport_conn[i]) {
                        c3cn = cdata->sport_conn[i];
                        cdata->sport_conn[i] = NULL;

                        spin_lock_bh(&c3cn->lock);
                        c3cn->cdev = NULL;
                        c3cn_set_flag(c3cn, C3CN_OFFLOAD_DOWN);
                        c3cn_closed(c3cn);
                        spin_unlock_bh(&c3cn->lock);
                }
        }

        for (i = 0; i < ports->nports; i++)
                NDEV2CDATA(ports->lldevs[i]) = NULL;

        cxgb3i_free_big_mem(cdata);
}

void cxgb3i_sdev_cleanup(void)
{
        struct cxgb3i_sdev_data *cdata;

        write_lock(&cdata_rwlock);
        list_for_each_entry(cdata, &cdata_list, list) {
                list_del(&cdata->list);
                sdev_data_cleanup(cdata);
        }
        write_unlock(&cdata_rwlock);
}

int cxgb3i_sdev_init(cxgb3_cpl_handler_func *cpl_handlers)
{
        cpl_handlers[CPL_ACT_ESTABLISH] = do_act_establish;
        cpl_handlers[CPL_ACT_OPEN_RPL] = do_act_open_rpl;
        cpl_handlers[CPL_PEER_CLOSE] = do_peer_close;
        cpl_handlers[CPL_ABORT_REQ_RSS] = do_abort_req;
        cpl_handlers[CPL_ABORT_RPL_RSS] = do_abort_rpl;
        cpl_handlers[CPL_CLOSE_CON_RPL] = do_close_con_rpl;
        cpl_handlers[CPL_TX_DMA_ACK] = do_wr_ack;
        cpl_handlers[CPL_ISCSI_HDR] = do_iscsi_hdr;

        if (cxgb3_max_connect > CXGB3I_MAX_CONN)
                cxgb3_max_connect = CXGB3I_MAX_CONN;
        return 0;
}

/**
 * cxgb3i_sdev_add - allocate and initialize resources for each adapter found
 * @cdev:       t3cdev adapter
 * @client:     cxgb3 driver client
 */
void cxgb3i_sdev_add(struct t3cdev *cdev, struct cxgb3_client *client)
{
        struct cxgb3i_sdev_data *cdata;
        struct ofld_page_info rx_page_info;
        unsigned int wr_len;
        int mapsize = cxgb3_max_connect * sizeof(struct s3_conn *);
        int i;

        cdata =  cxgb3i_alloc_big_mem(sizeof(*cdata) + mapsize, GFP_KERNEL);
        if (!cdata) {
                cxgb3i_log_warn("t3dev 0x%p, offload up, OOM %d.\n",
                                cdev, mapsize);
                return;
        }

        if (cdev->ctl(cdev, GET_WR_LEN, &wr_len) < 0 ||
            cdev->ctl(cdev, GET_PORTS, &cdata->ports) < 0 ||
            cdev->ctl(cdev, GET_RX_PAGE_INFO, &rx_page_info) < 0) {
                cxgb3i_log_warn("t3dev 0x%p, offload up, ioctl failed.\n",
                                cdev);
                goto free_cdata;
        }

        s3_init_wr_tab(wr_len);

        spin_lock_init(&cdata->lock);
        INIT_LIST_HEAD(&cdata->list);
        cdata->cdev = cdev;
        cdata->client = client;

        for (i = 0; i < cdata->ports.nports; i++)
                NDEV2CDATA(cdata->ports.lldevs[i]) = cdata;

        write_lock(&cdata_rwlock);
        list_add_tail(&cdata->list, &cdata_list);
        write_unlock(&cdata_rwlock);

        cxgb3i_log_info("t3dev 0x%p, offload up, added.\n", cdev);
        return;

free_cdata:
        cxgb3i_free_big_mem(cdata);
}

/**
 * cxgb3i_sdev_remove - free the allocated resources for the adapter
 * @cdev:       t3cdev adapter
 */
void cxgb3i_sdev_remove(struct t3cdev *cdev)
{
        struct cxgb3i_sdev_data *cdata = CXGB3_SDEV_DATA(cdev);

        cxgb3i_log_info("t3dev 0x%p, offload down, remove.\n", cdev);

        write_lock(&cdata_rwlock);
        list_del(&cdata->list);
        write_unlock(&cdata_rwlock);

        sdev_data_cleanup(cdata);
}