/*
 * Copyright (c) 2006, 2019 Oracle and/or its affiliates. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */
#include <linux/dmapool.h>
#include <linux/kernel.h>
#include <linux/in.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/ratelimit.h>
#include <net/addrconf.h>
#include <rdma/ib_cm.h>

#include "rds_single_path.h"
#include "rds.h"
#include "ib.h"
#include "ib_mr.h"

/*
 * Set the selected protocol version
 */
static void rds_ib_set_protocol(struct rds_connection *conn, unsigned int version)
{
        conn->c_version = version;
}

/*
 * Set up flow control
 */
static void rds_ib_set_flow_control(struct rds_connection *conn, u32 credits)
{
        struct rds_ib_connection *ic = conn->c_transport_data;

        if (rds_ib_sysctl_flow_control && credits != 0) {
                /* We're doing flow control */
                ic->i_flowctl = 1;
                rds_ib_send_add_credits(conn, credits);
        } else {
                ic->i_flowctl = 0;
        }
}

/*
 * Tune RNR behavior. Without flow control, we use a rather
 * low timeout, but not the absolute minimum - this should
 * be tunable.
 *
 * We already set the RNR retry count to 7 (which is the
 * smallest infinite number :-) above.
 * If flow control is off, we want to change this back to 0
 * so that we learn quickly when our credit accounting is
 * buggy.
 *
 * Caller passes in a qp_attr pointer - don't waste stack spacv
 * by allocation this twice.
 */
static void
rds_ib_tune_rnr(struct rds_ib_connection *ic, struct ib_qp_attr *attr)
{
        int ret;

        attr->min_rnr_timer = IB_RNR_TIMER_000_32;
        ret = ib_modify_qp(ic->i_cm_id->qp, attr, IB_QP_MIN_RNR_TIMER);
        if (ret)
                printk(KERN_NOTICE "ib_modify_qp(IB_QP_MIN_RNR_TIMER): err=%d\n", -ret);
}

/*
 * Connection established.
 * We get here for both outgoing and incoming connection.
 */
void rds_ib_cm_connect_complete(struct rds_connection *conn, struct rdma_cm_event *event)
{
        struct rds_ib_connection *ic = conn->c_transport_data;
        const union rds_ib_conn_priv *dp = NULL;
        struct ib_qp_attr qp_attr;
        __be64 ack_seq = 0;
        __be32 credit = 0;
        u8 major = 0;
        u8 minor = 0;
        int err;

        dp = event->param.conn.private_data;
        if (conn->c_isv6) {
                if (event->param.conn.private_data_len >=
                    sizeof(struct rds6_ib_connect_private)) {
                        major = dp->ricp_v6.dp_protocol_major;
                        minor = dp->ricp_v6.dp_protocol_minor;
                        credit = dp->ricp_v6.dp_credit;
                        /* dp structure start is not guaranteed to be 8 bytes
                         * aligned.  Since dp_ack_seq is 64-bit extended load
                         * operations can be used so go through get_unaligned
                         * to avoid unaligned errors.
                         */
                        ack_seq = get_unaligned(&dp->ricp_v6.dp_ack_seq);
                }
        } else if (event->param.conn.private_data_len >=
                   sizeof(struct rds_ib_connect_private)) {
                major = dp->ricp_v4.dp_protocol_major;
                minor = dp->ricp_v4.dp_protocol_minor;
                credit = dp->ricp_v4.dp_credit;
                ack_seq = get_unaligned(&dp->ricp_v4.dp_ack_seq);
        }

        /* make sure it isn't empty data */
        if (major) {
                rds_ib_set_protocol(conn, RDS_PROTOCOL(major, minor));
                rds_ib_set_flow_control(conn, be32_to_cpu(credit));
        }

        if (conn->c_version < RDS_PROTOCOL_VERSION) {
                if (conn->c_version != RDS_PROTOCOL_COMPAT_VERSION) {
                        pr_notice("RDS/IB: Connection <%pI6c,%pI6c> version %u.%u no longer supported\n",
                                  &conn->c_laddr, &conn->c_faddr,
                                  RDS_PROTOCOL_MAJOR(conn->c_version),
                                  RDS_PROTOCOL_MINOR(conn->c_version));
                        rds_conn_destroy(conn);
                        return;
                }
        }

        pr_notice("RDS/IB: %s conn connected <%pI6c,%pI6c,%d> version %u.%u%s\n",
                  ic->i_active_side ? "Active" : "Passive",
                  &conn->c_laddr, &conn->c_faddr, conn->c_tos,
                  RDS_PROTOCOL_MAJOR(conn->c_version),
                  RDS_PROTOCOL_MINOR(conn->c_version),
                  ic->i_flowctl ? ", flow control" : "");

        /* receive sl from the peer */
        ic->i_sl = ic->i_cm_id->route.path_rec->sl;

        atomic_set(&ic->i_cq_quiesce, 0);

        /* Init rings and fill recv. this needs to wait until protocol
         * negotiation is complete, since ring layout is different
         * from 3.1 to 4.1.
         */
        rds_ib_send_init_ring(ic);
        rds_ib_recv_init_ring(ic);
        /* Post receive buffers - as a side effect, this will update
         * the posted credit count. */
        rds_ib_recv_refill(conn, 1, GFP_KERNEL);

        /* Tune RNR behavior */
        rds_ib_tune_rnr(ic, &qp_attr);

        qp_attr.qp_state = IB_QPS_RTS;
        err = ib_modify_qp(ic->i_cm_id->qp, &qp_attr, IB_QP_STATE);
        if (err)
                printk(KERN_NOTICE "ib_modify_qp(IB_QP_STATE, RTS): err=%d\n", err);

        /* update ib_device with this local ipaddr */
        err = rds_ib_update_ipaddr(ic->rds_ibdev, &conn->c_laddr);
        if (err)
                printk(KERN_ERR "rds_ib_update_ipaddr failed (%d)\n",
                        err);

        /* If the peer gave us the last packet it saw, process this as if
         * we had received a regular ACK. */
        if (dp) {
                if (ack_seq)
                        rds_send_drop_acked(conn, be64_to_cpu(ack_seq),
                                            NULL);
        }

        conn->c_proposed_version = conn->c_version;
        rds_connect_complete(conn);
}

static void rds_ib_cm_fill_conn_param(struct rds_connection *conn,
                                      struct rdma_conn_param *conn_param,
                                      union rds_ib_conn_priv *dp,
                                      u32 protocol_version,
                                      u32 max_responder_resources,
                                      u32 max_initiator_depth,
                                      bool isv6)
{
        struct rds_ib_connection *ic = conn->c_transport_data;
        struct rds_ib_device *rds_ibdev = ic->rds_ibdev;

        memset(conn_param, 0, sizeof(struct rdma_conn_param));

        conn_param->responder_resources =
                min_t(u32, rds_ibdev->max_responder_resources, max_responder_resources);
        conn_param->initiator_depth =
                min_t(u32, rds_ibdev->max_initiator_depth, max_initiator_depth);
        conn_param->retry_count = min_t(unsigned int, rds_ib_retry_count, 7);
        conn_param->rnr_retry_count = 7;

        if (dp) {
                memset(dp, 0, sizeof(*dp));
                if (isv6) {
                        dp->ricp_v6.dp_saddr = conn->c_laddr;
                        dp->ricp_v6.dp_daddr = conn->c_faddr;
                        dp->ricp_v6.dp_protocol_major =
                            RDS_PROTOCOL_MAJOR(protocol_version);
                        dp->ricp_v6.dp_protocol_minor =
                            RDS_PROTOCOL_MINOR(protocol_version);
                        dp->ricp_v6.dp_protocol_minor_mask =
                            cpu_to_be16(RDS_IB_SUPPORTED_PROTOCOLS);
                        dp->ricp_v6.dp_ack_seq =
                            cpu_to_be64(rds_ib_piggyb_ack(ic));
                        dp->ricp_v6.dp_cmn.ricpc_dp_toss = conn->c_tos;

                        conn_param->private_data = &dp->ricp_v6;
                        conn_param->private_data_len = sizeof(dp->ricp_v6);
                } else {
                        dp->ricp_v4.dp_saddr = conn->c_laddr.s6_addr32[3];
                        dp->ricp_v4.dp_daddr = conn->c_faddr.s6_addr32[3];
                        dp->ricp_v4.dp_protocol_major =
                            RDS_PROTOCOL_MAJOR(protocol_version);
                        dp->ricp_v4.dp_protocol_minor =
                            RDS_PROTOCOL_MINOR(protocol_version);
                        dp->ricp_v4.dp_protocol_minor_mask =
                            cpu_to_be16(RDS_IB_SUPPORTED_PROTOCOLS);
                        dp->ricp_v4.dp_ack_seq =
                            cpu_to_be64(rds_ib_piggyb_ack(ic));
                        dp->ricp_v4.dp_cmn.ricpc_dp_toss = conn->c_tos;

                        conn_param->private_data = &dp->ricp_v4;
                        conn_param->private_data_len = sizeof(dp->ricp_v4);
                }

                /* Advertise flow control */
                if (ic->i_flowctl) {
                        unsigned int credits;

                        credits = IB_GET_POST_CREDITS
                                (atomic_read(&ic->i_credits));
                        if (isv6)
                                dp->ricp_v6.dp_credit = cpu_to_be32(credits);
                        else
                                dp->ricp_v4.dp_credit = cpu_to_be32(credits);
                        atomic_sub(IB_SET_POST_CREDITS(credits),
                                   &ic->i_credits);
                }
        }
}

static void rds_ib_cq_event_handler(struct ib_event *event, void *data)
{
        rdsdebug("event %u (%s) data %p\n",
                 event->event, ib_event_msg(event->event), data);
}

/* Plucking the oldest entry from the ring can be done concurrently with
 * the thread refilling the ring.  Each ring operation is protected by
 * spinlocks and the transient state of refilling doesn't change the
 * recording of which entry is oldest.
 *
 * This relies on IB only calling one cq comp_handler for each cq so that
 * there will only be one caller of rds_recv_incoming() per RDS connection.
 */
static void rds_ib_cq_comp_handler_recv(struct ib_cq *cq, void *context)
{
        struct rds_connection *conn = context;
        struct rds_ib_connection *ic = conn->c_transport_data;

        rdsdebug("conn %p cq %p\n", conn, cq);

        rds_ib_stats_inc(s_ib_evt_handler_call);

        tasklet_schedule(&ic->i_recv_tasklet);
}

static void poll_scq(struct rds_ib_connection *ic, struct ib_cq *cq,
                     struct ib_wc *wcs)
{
        int nr, i;
        struct ib_wc *wc;

        while ((nr = ib_poll_cq(cq, RDS_IB_WC_MAX, wcs)) > 0) {
                for (i = 0; i < nr; i++) {
                        wc = wcs + i;
                        rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n",
                                 (unsigned long long)wc->wr_id, wc->status,
                                 wc->byte_len, be32_to_cpu(wc->ex.imm_data));

                        if (wc->wr_id <= ic->i_send_ring.w_nr ||
                            wc->wr_id == RDS_IB_ACK_WR_ID)
                                rds_ib_send_cqe_handler(ic, wc);
                        else
                                rds_ib_mr_cqe_handler(ic, wc);

                }
        }
}

static void rds_ib_tasklet_fn_send(unsigned long data)
{
        struct rds_ib_connection *ic = (struct rds_ib_connection *)data;
        struct rds_connection *conn = ic->conn;

        rds_ib_stats_inc(s_ib_tasklet_call);

        /* if cq has been already reaped, ignore incoming cq event */
        if (atomic_read(&ic->i_cq_quiesce))
                return;

        poll_scq(ic, ic->i_send_cq, ic->i_send_wc);
        ib_req_notify_cq(ic->i_send_cq, IB_CQ_NEXT_COMP);
        poll_scq(ic, ic->i_send_cq, ic->i_send_wc);

        if (rds_conn_up(conn) &&
            (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ||
            test_bit(0, &conn->c_map_queued)))
                rds_send_xmit(&ic->conn->c_path[0]);
}

static void poll_rcq(struct rds_ib_connection *ic, struct ib_cq *cq,
                     struct ib_wc *wcs,
                     struct rds_ib_ack_state *ack_state)
{
        int nr, i;
        struct ib_wc *wc;

        while ((nr = ib_poll_cq(cq, RDS_IB_WC_MAX, wcs)) > 0) {
                for (i = 0; i < nr; i++) {
                        wc = wcs + i;
                        rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n",
                                 (unsigned long long)wc->wr_id, wc->status,
                                 wc->byte_len, be32_to_cpu(wc->ex.imm_data));

                        rds_ib_recv_cqe_handler(ic, wc, ack_state);
                }
        }
}

static void rds_ib_tasklet_fn_recv(unsigned long data)
{
        struct rds_ib_connection *ic = (struct rds_ib_connection *)data;
        struct rds_connection *conn = ic->conn;
        struct rds_ib_device *rds_ibdev = ic->rds_ibdev;
        struct rds_ib_ack_state state;

        if (!rds_ibdev)
                rds_conn_drop(conn);

        rds_ib_stats_inc(s_ib_tasklet_call);

        /* if cq has been already reaped, ignore incoming cq event */
        if (atomic_read(&ic->i_cq_quiesce))
                return;

        memset(&state, 0, sizeof(state));
        poll_rcq(ic, ic->i_recv_cq, ic->i_recv_wc, &state);
        ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED);
        poll_rcq(ic, ic->i_recv_cq, ic->i_recv_wc, &state);

        if (state.ack_next_valid)
                rds_ib_set_ack(ic, state.ack_next, state.ack_required);
        if (state.ack_recv_valid && state.ack_recv > ic->i_ack_recv) {
                rds_send_drop_acked(conn, state.ack_recv, NULL);
                ic->i_ack_recv = state.ack_recv;
        }

        if (rds_conn_up(conn))
                rds_ib_attempt_ack(ic);
}

static void rds_ib_qp_event_handler(struct ib_event *event, void *data)
{
        struct rds_connection *conn = data;
        struct rds_ib_connection *ic = conn->c_transport_data;

        rdsdebug("conn %p ic %p event %u (%s)\n", conn, ic, event->event,
                 ib_event_msg(event->event));

        switch (event->event) {
        case IB_EVENT_COMM_EST:
                rdma_notify(ic->i_cm_id, IB_EVENT_COMM_EST);
                break;
        default:
                rdsdebug("Fatal QP Event %u (%s) - connection %pI6c->%pI6c, reconnecting\n",
                         event->event, ib_event_msg(event->event),
                         &conn->c_laddr, &conn->c_faddr);
                rds_conn_drop(conn);
                break;
        }
}

static void rds_ib_cq_comp_handler_send(struct ib_cq *cq, void *context)
{
        struct rds_connection *conn = context;
        struct rds_ib_connection *ic = conn->c_transport_data;

        rdsdebug("conn %p cq %p\n", conn, cq);

        rds_ib_stats_inc(s_ib_evt_handler_call);

        tasklet_schedule(&ic->i_send_tasklet);
}

static inline int ibdev_get_unused_vector(struct rds_ib_device *rds_ibdev)
{
        int min = rds_ibdev->vector_load[rds_ibdev->dev->num_comp_vectors - 1];
        int index = rds_ibdev->dev->num_comp_vectors - 1;
        int i;

        for (i = rds_ibdev->dev->num_comp_vectors - 1; i >= 0; i--) {
                if (rds_ibdev->vector_load[i] < min) {
                        index = i;
                        min = rds_ibdev->vector_load[i];
                }
        }

        rds_ibdev->vector_load[index]++;
        return index;
}

static inline void ibdev_put_vector(struct rds_ib_device *rds_ibdev, int index)
{
        rds_ibdev->vector_load[index]--;
}

/* Allocate DMA coherent memory to be used to store struct rds_header for
 * sending/receiving packets.  The pointers to the DMA memory and the
 * associated DMA addresses are stored in two arrays.
 *
 * @ibdev: the IB device
 * @pool: the DMA memory pool
 * @dma_addrs: pointer to the array for storing DMA addresses
 * @num_hdrs: number of headers to allocate
 *
 * It returns the pointer to the array storing the DMA memory pointers.  On
 * error, NULL pointer is returned.
 */
struct rds_header **rds_dma_hdrs_alloc(struct ib_device *ibdev,
                                       struct dma_pool *pool,
                                       dma_addr_t **dma_addrs, u32 num_hdrs)
{
        struct rds_header **hdrs;
        dma_addr_t *hdr_daddrs;
        u32 i;

        hdrs = kvmalloc_node(sizeof(*hdrs) * num_hdrs, GFP_KERNEL,
                             ibdev_to_node(ibdev));
        if (!hdrs)
                return NULL;

        hdr_daddrs = kvmalloc_node(sizeof(*hdr_daddrs) * num_hdrs, GFP_KERNEL,
                                   ibdev_to_node(ibdev));
        if (!hdr_daddrs) {
                kvfree(hdrs);
                return NULL;
        }

        for (i = 0; i < num_hdrs; i++) {
                hdrs[i] = dma_pool_zalloc(pool, GFP_KERNEL, &hdr_daddrs[i]);
                if (!hdrs[i]) {
                        rds_dma_hdrs_free(pool, hdrs, hdr_daddrs, i);
                        return NULL;
                }
        }

        *dma_addrs = hdr_daddrs;
        return hdrs;
}

/* Free the DMA memory used to store struct rds_header.
 *
 * @pool: the DMA memory pool
 * @hdrs: pointer to the array storing DMA memory pointers
 * @dma_addrs: pointer to the array storing DMA addresses
 * @num_hdars: number of headers to free.
 */
void rds_dma_hdrs_free(struct dma_pool *pool, struct rds_header **hdrs,
                       dma_addr_t *dma_addrs, u32 num_hdrs)
{
        u32 i;

        for (i = 0; i < num_hdrs; i++)
                dma_pool_free(pool, hdrs[i], dma_addrs[i]);
        kvfree(hdrs);
        kvfree(dma_addrs);
}

/*
 * This needs to be very careful to not leave IS_ERR pointers around for
 * cleanup to trip over.
 */
static int rds_ib_setup_qp(struct rds_connection *conn)
{
        struct rds_ib_connection *ic = conn->c_transport_data;
        struct ib_device *dev = ic->i_cm_id->device;
        struct ib_qp_init_attr attr;
        struct ib_cq_init_attr cq_attr = {};
        struct rds_ib_device *rds_ibdev;
        unsigned long max_wrs;
        int ret, fr_queue_space;
        struct dma_pool *pool;

        /*
         * It's normal to see a null device if an incoming connection races
         * with device removal, so we don't print a warning.
         */
        rds_ibdev = rds_ib_get_client_data(dev);
        if (!rds_ibdev)
                return -EOPNOTSUPP;

        /* The fr_queue_space is currently set to 512, to add extra space on
         * completion queue and send queue. This extra space is used for FRWR
         * registration and invalidation work requests
         */
        fr_queue_space = RDS_IB_DEFAULT_FR_WR;

        /* add the conn now so that connection establishment has the dev */
        rds_ib_add_conn(rds_ibdev, conn);

        max_wrs = rds_ibdev->max_wrs < rds_ib_sysctl_max_send_wr + 1 ?
                rds_ibdev->max_wrs - 1 : rds_ib_sysctl_max_send_wr;
        if (ic->i_send_ring.w_nr != max_wrs)
                rds_ib_ring_resize(&ic->i_send_ring, max_wrs);

        max_wrs = rds_ibdev->max_wrs < rds_ib_sysctl_max_recv_wr + 1 ?
                rds_ibdev->max_wrs - 1 : rds_ib_sysctl_max_recv_wr;
        if (ic->i_recv_ring.w_nr != max_wrs)
                rds_ib_ring_resize(&ic->i_recv_ring, max_wrs);

        /* Protection domain and memory range */
        ic->i_pd = rds_ibdev->pd;

        ic->i_scq_vector = ibdev_get_unused_vector(rds_ibdev);
        cq_attr.cqe = ic->i_send_ring.w_nr + fr_queue_space + 1;
        cq_attr.comp_vector = ic->i_scq_vector;
        ic->i_send_cq = ib_create_cq(dev, rds_ib_cq_comp_handler_send,
                                     rds_ib_cq_event_handler, conn,
                                     &cq_attr);
        if (IS_ERR(ic->i_send_cq)) {
                ret = PTR_ERR(ic->i_send_cq);
                ic->i_send_cq = NULL;
                ibdev_put_vector(rds_ibdev, ic->i_scq_vector);
                rdsdebug("ib_create_cq send failed: %d\n", ret);
                goto rds_ibdev_out;
        }

        ic->i_rcq_vector = ibdev_get_unused_vector(rds_ibdev);
        cq_attr.cqe = ic->i_recv_ring.w_nr;
        cq_attr.comp_vector = ic->i_rcq_vector;
        ic->i_recv_cq = ib_create_cq(dev, rds_ib_cq_comp_handler_recv,
                                     rds_ib_cq_event_handler, conn,
                                     &cq_attr);
        if (IS_ERR(ic->i_recv_cq)) {
                ret = PTR_ERR(ic->i_recv_cq);
                ic->i_recv_cq = NULL;
                ibdev_put_vector(rds_ibdev, ic->i_rcq_vector);
                rdsdebug("ib_create_cq recv failed: %d\n", ret);
                goto send_cq_out;
        }

        ret = ib_req_notify_cq(ic->i_send_cq, IB_CQ_NEXT_COMP);
        if (ret) {
                rdsdebug("ib_req_notify_cq send failed: %d\n", ret);
                goto recv_cq_out;
        }

        ret = ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED);
        if (ret) {
                rdsdebug("ib_req_notify_cq recv failed: %d\n", ret);
                goto recv_cq_out;
        }

        /* XXX negotiate max send/recv with remote? */
        memset(&attr, 0, sizeof(attr));
        attr.event_handler = rds_ib_qp_event_handler;
        attr.qp_context = conn;
        /* + 1 to allow for the single ack message */
        attr.cap.max_send_wr = ic->i_send_ring.w_nr + fr_queue_space + 1;
        attr.cap.max_recv_wr = ic->i_recv_ring.w_nr + 1;
        attr.cap.max_send_sge = rds_ibdev->max_sge;
        attr.cap.max_recv_sge = RDS_IB_RECV_SGE;
        attr.sq_sig_type = IB_SIGNAL_REQ_WR;
        attr.qp_type = IB_QPT_RC;
        attr.send_cq = ic->i_send_cq;
        attr.recv_cq = ic->i_recv_cq;

        /*
         * XXX this can fail if max_*_wr is too large?  Are we supposed
         * to back off until we get a value that the hardware can support?
         */
        ret = rdma_create_qp(ic->i_cm_id, ic->i_pd, &attr);
        if (ret) {
                rdsdebug("rdma_create_qp failed: %d\n", ret);
                goto recv_cq_out;
        }

        pool = rds_ibdev->rid_hdrs_pool;
        ic->i_send_hdrs = rds_dma_hdrs_alloc(dev, pool, &ic->i_send_hdrs_dma,
                                             ic->i_send_ring.w_nr);
        if (!ic->i_send_hdrs) {
                ret = -ENOMEM;
                rdsdebug("DMA send hdrs alloc failed\n");
                goto qp_out;
        }

        ic->i_recv_hdrs = rds_dma_hdrs_alloc(dev, pool, &ic->i_recv_hdrs_dma,
                                             ic->i_recv_ring.w_nr);
        if (!ic->i_recv_hdrs) {
                ret = -ENOMEM;
                rdsdebug("DMA recv hdrs alloc failed\n");
                goto send_hdrs_dma_out;
        }

        ic->i_ack = dma_pool_zalloc(pool, GFP_KERNEL,
                                    &ic->i_ack_dma);
        if (!ic->i_ack) {
                ret = -ENOMEM;
                rdsdebug("DMA ack header alloc failed\n");
                goto recv_hdrs_dma_out;
        }

        ic->i_sends = vzalloc_node(array_size(sizeof(struct rds_ib_send_work),
                                              ic->i_send_ring.w_nr),
                                   ibdev_to_node(dev));
        if (!ic->i_sends) {
                ret = -ENOMEM;
                rdsdebug("send allocation failed\n");
                goto ack_dma_out;
        }

        ic->i_recvs = vzalloc_node(array_size(sizeof(struct rds_ib_recv_work),
                                              ic->i_recv_ring.w_nr),
                                   ibdev_to_node(dev));
        if (!ic->i_recvs) {
                ret = -ENOMEM;
                rdsdebug("recv allocation failed\n");
                goto sends_out;
        }

        rds_ib_recv_init_ack(ic);

        rdsdebug("conn %p pd %p cq %p %p\n", conn, ic->i_pd,
                 ic->i_send_cq, ic->i_recv_cq);

        goto out;

sends_out:
        vfree(ic->i_sends);

ack_dma_out:
        dma_pool_free(pool, ic->i_ack, ic->i_ack_dma);
        ic->i_ack = NULL;

recv_hdrs_dma_out:
        rds_dma_hdrs_free(pool, ic->i_recv_hdrs, ic->i_recv_hdrs_dma,
                          ic->i_recv_ring.w_nr);
        ic->i_recv_hdrs = NULL;
        ic->i_recv_hdrs_dma = NULL;

send_hdrs_dma_out:
        rds_dma_hdrs_free(pool, ic->i_send_hdrs, ic->i_send_hdrs_dma,
                          ic->i_send_ring.w_nr);
        ic->i_send_hdrs = NULL;
        ic->i_send_hdrs_dma = NULL;

qp_out:
        rdma_destroy_qp(ic->i_cm_id);
recv_cq_out:
        ib_destroy_cq(ic->i_recv_cq);
        ic->i_recv_cq = NULL;
send_cq_out:
        ib_destroy_cq(ic->i_send_cq);
        ic->i_send_cq = NULL;
rds_ibdev_out:
        rds_ib_remove_conn(rds_ibdev, conn);
out:
        rds_ib_dev_put(rds_ibdev);

        return ret;
}

static u32 rds_ib_protocol_compatible(struct rdma_cm_event *event, bool isv6)
{
        const union rds_ib_conn_priv *dp = event->param.conn.private_data;
        u8 data_len, major, minor;
        u32 version = 0;
        __be16 mask;
        u16 common;

        /*
         * rdma_cm private data is odd - when there is any private data in the
         * request, we will be given a pretty large buffer without telling us the
         * original size. The only way to tell the difference is by looking at
         * the contents, which are initialized to zero.
         * If the protocol version fields aren't set, this is a connection attempt
         * from an older version. This could could be 3.0 or 2.0 - we can't tell.
         * We really should have changed this for OFED 1.3 :-(
         */

        /* Be paranoid. RDS always has privdata */
        if (!event->param.conn.private_data_len) {
                printk(KERN_NOTICE "RDS incoming connection has no private data, "
                        "rejecting\n");
                return 0;
        }

        if (isv6) {
                data_len = sizeof(struct rds6_ib_connect_private);
                major = dp->ricp_v6.dp_protocol_major;
                minor = dp->ricp_v6.dp_protocol_minor;
                mask = dp->ricp_v6.dp_protocol_minor_mask;
        } else {
                data_len = sizeof(struct rds_ib_connect_private);
                major = dp->ricp_v4.dp_protocol_major;
                minor = dp->ricp_v4.dp_protocol_minor;
                mask = dp->ricp_v4.dp_protocol_minor_mask;
        }

        /* Even if len is crap *now* I still want to check it. -ASG */
        if (event->param.conn.private_data_len < data_len || major == 0)
                return RDS_PROTOCOL_4_0;

        common = be16_to_cpu(mask) & RDS_IB_SUPPORTED_PROTOCOLS;
        if (major == 4 && common) {
                version = RDS_PROTOCOL_4_0;
                while ((common >>= 1) != 0)
                        version++;
        } else if (RDS_PROTOCOL_COMPAT_VERSION ==
                   RDS_PROTOCOL(major, minor)) {
                version = RDS_PROTOCOL_COMPAT_VERSION;
        } else {
                if (isv6)
                        printk_ratelimited(KERN_NOTICE "RDS: Connection from %pI6c using incompatible protocol version %u.%u\n",
                                           &dp->ricp_v6.dp_saddr, major, minor);
                else
                        printk_ratelimited(KERN_NOTICE "RDS: Connection from %pI4 using incompatible protocol version %u.%u\n",
                                           &dp->ricp_v4.dp_saddr, major, minor);
        }
        return version;
}

#if IS_ENABLED(CONFIG_IPV6)
/* Given an IPv6 address, find the net_device which hosts that address and
 * return its index.  This is used by the rds_ib_cm_handle_connect() code to
 * find the interface index of where an incoming request comes from when
 * the request is using a link local address.
 *
 * Note one problem in this search.  It is possible that two interfaces have
 * the same link local address.  Unfortunately, this cannot be solved unless
 * the underlying layer gives us the interface which an incoming RDMA connect
 * request comes from.
 */
static u32 __rds_find_ifindex(struct net *net, const struct in6_addr *addr)
{
        struct net_device *dev;
        int idx = 0;

        rcu_read_lock();
        for_each_netdev_rcu(net, dev) {
                if (ipv6_chk_addr(net, addr, dev, 1)) {
                        idx = dev->ifindex;
                        break;
                }
        }
        rcu_read_unlock();

        return idx;
}
#endif

int rds_ib_cm_handle_connect(struct rdma_cm_id *cm_id,
                             struct rdma_cm_event *event, bool isv6)
{
        __be64 lguid = cm_id->route.path_rec->sgid.global.interface_id;
        __be64 fguid = cm_id->route.path_rec->dgid.global.interface_id;
        const struct rds_ib_conn_priv_cmn *dp_cmn;
        struct rds_connection *conn = NULL;
        struct rds_ib_connection *ic = NULL;
        struct rdma_conn_param conn_param;
        const union rds_ib_conn_priv *dp;
        union rds_ib_conn_priv dp_rep;
        struct in6_addr s_mapped_addr;
        struct in6_addr d_mapped_addr;
        const struct in6_addr *saddr6;
        const struct in6_addr *daddr6;
        int destroy = 1;
        u32 ifindex = 0;
        u32 version;
        int err = 1;

        /* Check whether the remote protocol version matches ours. */
        version = rds_ib_protocol_compatible(event, isv6);
        if (!version) {
                err = RDS_RDMA_REJ_INCOMPAT;
                goto out;
        }

        dp = event->param.conn.private_data;
        if (isv6) {
#if IS_ENABLED(CONFIG_IPV6)
                dp_cmn = &dp->ricp_v6.dp_cmn;
                saddr6 = &dp->ricp_v6.dp_saddr;
                daddr6 = &dp->ricp_v6.dp_daddr;
                /* If either address is link local, need to find the
                 * interface index in order to create a proper RDS
                 * connection.
                 */
                if (ipv6_addr_type(daddr6) & IPV6_ADDR_LINKLOCAL) {
                        /* Using init_net for now ..  */
                        ifindex = __rds_find_ifindex(&init_net, daddr6);
                        /* No index found...  Need to bail out. */
                        if (ifindex == 0) {
                                err = -EOPNOTSUPP;
                                goto out;
                        }
                } else if (ipv6_addr_type(saddr6) & IPV6_ADDR_LINKLOCAL) {
                        /* Use our address to find the correct index. */
                        ifindex = __rds_find_ifindex(&init_net, daddr6);
                        /* No index found...  Need to bail out. */
                        if (ifindex == 0) {
                                err = -EOPNOTSUPP;
                                goto out;
                        }
                }
#else
                err = -EOPNOTSUPP;
                goto out;
#endif
        } else {
                dp_cmn = &dp->ricp_v4.dp_cmn;
                ipv6_addr_set_v4mapped(dp->ricp_v4.dp_saddr, &s_mapped_addr);
                ipv6_addr_set_v4mapped(dp->ricp_v4.dp_daddr, &d_mapped_addr);
                saddr6 = &s_mapped_addr;
                daddr6 = &d_mapped_addr;
        }

        rdsdebug("saddr %pI6c daddr %pI6c RDSv%u.%u lguid 0x%llx fguid 0x%llx, tos:%d\n",
                 saddr6, daddr6, RDS_PROTOCOL_MAJOR(version),
                 RDS_PROTOCOL_MINOR(version),
                 (unsigned long long)be64_to_cpu(lguid),
                 (unsigned long long)be64_to_cpu(fguid), dp_cmn->ricpc_dp_toss);

        /* RDS/IB is not currently netns aware, thus init_net */
        conn = rds_conn_create(&init_net, daddr6, saddr6,
                               &rds_ib_transport, dp_cmn->ricpc_dp_toss,
                               GFP_KERNEL, ifindex);
        if (IS_ERR(conn)) {
                rdsdebug("rds_conn_create failed (%ld)\n", PTR_ERR(conn));
                conn = NULL;
                goto out;
        }

        /*
         * The connection request may occur while the
         * previous connection exist, e.g. in case of failover.
         * But as connections may be initiated simultaneously
         * by both hosts, we have a random backoff mechanism -
         * see the comment above rds_queue_reconnect()
         */
        mutex_lock(&conn->c_cm_lock);
        if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_CONNECTING)) {
                if (rds_conn_state(conn) == RDS_CONN_UP) {
                        rdsdebug("incoming connect while connecting\n");
                        rds_conn_drop(conn);
                        rds_ib_stats_inc(s_ib_listen_closed_stale);
                } else
                if (rds_conn_state(conn) == RDS_CONN_CONNECTING) {
                        /* Wait and see - our connect may still be succeeding */
                        rds_ib_stats_inc(s_ib_connect_raced);
                }
                goto out;
        }

        ic = conn->c_transport_data;

        rds_ib_set_protocol(conn, version);
        rds_ib_set_flow_control(conn, be32_to_cpu(dp_cmn->ricpc_credit));

        /* If the peer gave us the last packet it saw, process this as if
         * we had received a regular ACK. */
        if (dp_cmn->ricpc_ack_seq)
                rds_send_drop_acked(conn, be64_to_cpu(dp_cmn->ricpc_ack_seq),
                                    NULL);

        BUG_ON(cm_id->context);
        BUG_ON(ic->i_cm_id);

        ic->i_cm_id = cm_id;
        cm_id->context = conn;

        /* We got halfway through setting up the ib_connection, if we
         * fail now, we have to take the long route out of this mess. */
        destroy = 0;

        err = rds_ib_setup_qp(conn);
        if (err) {
                rds_ib_conn_error(conn, "rds_ib_setup_qp failed (%d)\n", err);
                goto out;
        }

        rds_ib_cm_fill_conn_param(conn, &conn_param, &dp_rep, version,
                                  event->param.conn.responder_resources,
                                  event->param.conn.initiator_depth, isv6);

        /* rdma_accept() calls rdma_reject() internally if it fails */
        if (rdma_accept(cm_id, &conn_param))
                rds_ib_conn_error(conn, "rdma_accept failed\n");

out:
        if (conn)
                mutex_unlock(&conn->c_cm_lock);
        if (err)
                rdma_reject(cm_id, &err, sizeof(int),
                            IB_CM_REJ_CONSUMER_DEFINED);
        return destroy;
}


int rds_ib_cm_initiate_connect(struct rdma_cm_id *cm_id, bool isv6)
{
        struct rds_connection *conn = cm_id->context;
        struct rds_ib_connection *ic = conn->c_transport_data;
        struct rdma_conn_param conn_param;
        union rds_ib_conn_priv dp;
        int ret;

        /* If the peer doesn't do protocol negotiation, we must
         * default to RDSv3.0 */
        rds_ib_set_protocol(conn, RDS_PROTOCOL_4_1);
        ic->i_flowctl = rds_ib_sysctl_flow_control;     /* advertise flow control */

        ret = rds_ib_setup_qp(conn);
        if (ret) {
                rds_ib_conn_error(conn, "rds_ib_setup_qp failed (%d)\n", ret);
                goto out;
        }

        rds_ib_cm_fill_conn_param(conn, &conn_param, &dp,
                                  conn->c_proposed_version,
                                  UINT_MAX, UINT_MAX, isv6);
        ret = rdma_connect(cm_id, &conn_param);
        if (ret)
                rds_ib_conn_error(conn, "rdma_connect failed (%d)\n", ret);

out:
        /* Beware - returning non-zero tells the rdma_cm to destroy
         * the cm_id. We should certainly not do it as long as we still
         * "own" the cm_id. */
        if (ret) {
                if (ic->i_cm_id == cm_id)
                        ret = 0;
        }
        ic->i_active_side = true;
        return ret;
}

int rds_ib_conn_path_connect(struct rds_conn_path *cp)
{
        struct rds_connection *conn = cp->cp_conn;
        struct sockaddr_storage src, dest;
        rdma_cm_event_handler handler;
        struct rds_ib_connection *ic;
        int ret;

        ic = conn->c_transport_data;

        /* XXX I wonder what affect the port space has */
        /* delegate cm event handler to rdma_transport */
#if IS_ENABLED(CONFIG_IPV6)
        if (conn->c_isv6)
                handler = rds6_rdma_cm_event_handler;
        else
#endif
                handler = rds_rdma_cm_event_handler;
        ic->i_cm_id = rdma_create_id(&init_net, handler, conn,
                                     RDMA_PS_TCP, IB_QPT_RC);
        if (IS_ERR(ic->i_cm_id)) {
                ret = PTR_ERR(ic->i_cm_id);
                ic->i_cm_id = NULL;
                rdsdebug("rdma_create_id() failed: %d\n", ret);
                goto out;
        }

        rdsdebug("created cm id %p for conn %p\n", ic->i_cm_id, conn);

        if (ipv6_addr_v4mapped(&conn->c_faddr)) {
                struct sockaddr_in *sin;

                sin = (struct sockaddr_in *)&src;
                sin->sin_family = AF_INET;
                sin->sin_addr.s_addr = conn->c_laddr.s6_addr32[3];
                sin->sin_port = 0;

                sin = (struct sockaddr_in *)&dest;
                sin->sin_family = AF_INET;
                sin->sin_addr.s_addr = conn->c_faddr.s6_addr32[3];
                sin->sin_port = htons(RDS_PORT);
        } else {
                struct sockaddr_in6 *sin6;

                sin6 = (struct sockaddr_in6 *)&src;
                sin6->sin6_family = AF_INET6;
                sin6->sin6_addr = conn->c_laddr;
                sin6->sin6_port = 0;
                sin6->sin6_scope_id = conn->c_dev_if;

                sin6 = (struct sockaddr_in6 *)&dest;
                sin6->sin6_family = AF_INET6;
                sin6->sin6_addr = conn->c_faddr;
                sin6->sin6_port = htons(RDS_CM_PORT);
                sin6->sin6_scope_id = conn->c_dev_if;
        }

        ret = rdma_resolve_addr(ic->i_cm_id, (struct sockaddr *)&src,
                                (struct sockaddr *)&dest,
                                RDS_RDMA_RESOLVE_TIMEOUT_MS);
        if (ret) {
                rdsdebug("addr resolve failed for cm id %p: %d\n", ic->i_cm_id,
                         ret);
                rdma_destroy_id(ic->i_cm_id);
                ic->i_cm_id = NULL;
        }

out:
        return ret;
}

/*
 * This is so careful about only cleaning up resources that were built up
 * so that it can be called at any point during startup.  In fact it
 * can be called multiple times for a given connection.
 */
void rds_ib_conn_path_shutdown(struct rds_conn_path *cp)
{
        struct rds_connection *conn = cp->cp_conn;
        struct rds_ib_connection *ic = conn->c_transport_data;
        int err = 0;

        rdsdebug("cm %p pd %p cq %p %p qp %p\n", ic->i_cm_id,
                 ic->i_pd, ic->i_send_cq, ic->i_recv_cq,
                 ic->i_cm_id ? ic->i_cm_id->qp : NULL);

        if (ic->i_cm_id) {
                rdsdebug("disconnecting cm %p\n", ic->i_cm_id);
                err = rdma_disconnect(ic->i_cm_id);
                if (err) {
                        /* Actually this may happen quite frequently, when
                         * an outgoing connect raced with an incoming connect.
                         */
                        rdsdebug("failed to disconnect, cm: %p err %d\n",
                                ic->i_cm_id, err);
                }

                /* kick off "flush_worker" for all pools in order to reap
                 * all FRMR registrations that are still marked "FRMR_IS_INUSE"
                 */
                rds_ib_flush_mrs();

                /*
                 * We want to wait for tx and rx completion to finish
                 * before we tear down the connection, but we have to be
                 * careful not to get stuck waiting on a send ring that
                 * only has unsignaled sends in it.  We've shutdown new
                 * sends before getting here so by waiting for signaled
                 * sends to complete we're ensured that there will be no
                 * more tx processing.
                 */
                wait_event(rds_ib_ring_empty_wait,
                           rds_ib_ring_empty(&ic->i_recv_ring) &&
                           (atomic_read(&ic->i_signaled_sends) == 0) &&
                           (atomic_read(&ic->i_fastreg_inuse_count) == 0) &&
                           (atomic_read(&ic->i_fastreg_wrs) == RDS_IB_DEFAULT_FR_WR));
                tasklet_kill(&ic->i_send_tasklet);
                tasklet_kill(&ic->i_recv_tasklet);

                atomic_set(&ic->i_cq_quiesce, 1);

                /* first destroy the ib state that generates callbacks */
                if (ic->i_cm_id->qp)
                        rdma_destroy_qp(ic->i_cm_id);
                if (ic->i_send_cq) {
                        if (ic->rds_ibdev)
                                ibdev_put_vector(ic->rds_ibdev, ic->i_scq_vector);
                        ib_destroy_cq(ic->i_send_cq);
                }

                if (ic->i_recv_cq) {
                        if (ic->rds_ibdev)
                                ibdev_put_vector(ic->rds_ibdev, ic->i_rcq_vector);
                        ib_destroy_cq(ic->i_recv_cq);
                }

                if (ic->rds_ibdev) {
                        struct dma_pool *pool;

                        pool = ic->rds_ibdev->rid_hdrs_pool;

                        /* then free the resources that ib callbacks use */
                        if (ic->i_send_hdrs) {
                                rds_dma_hdrs_free(pool, ic->i_send_hdrs,
                                                  ic->i_send_hdrs_dma,
                                                  ic->i_send_ring.w_nr);
                                ic->i_send_hdrs = NULL;
                                ic->i_send_hdrs_dma = NULL;
                        }

                        if (ic->i_recv_hdrs) {
                                rds_dma_hdrs_free(pool, ic->i_recv_hdrs,
                                                  ic->i_recv_hdrs_dma,
                                                  ic->i_recv_ring.w_nr);
                                ic->i_recv_hdrs = NULL;
                                ic->i_recv_hdrs_dma = NULL;
                        }

                        if (ic->i_ack) {
                                dma_pool_free(pool, ic->i_ack, ic->i_ack_dma);
                                ic->i_ack = NULL;
                        }
                } else {
                        WARN_ON(ic->i_send_hdrs);
                        WARN_ON(ic->i_send_hdrs_dma);
                        WARN_ON(ic->i_recv_hdrs);
                        WARN_ON(ic->i_recv_hdrs_dma);
                        WARN_ON(ic->i_ack);
                }

                if (ic->i_sends)
                        rds_ib_send_clear_ring(ic);
                if (ic->i_recvs)
                        rds_ib_recv_clear_ring(ic);

                rdma_destroy_id(ic->i_cm_id);

                /*
                 * Move connection back to the nodev list.
                 */
                if (ic->rds_ibdev)
                        rds_ib_remove_conn(ic->rds_ibdev, conn);

                ic->i_cm_id = NULL;
                ic->i_pd = NULL;
                ic->i_send_cq = NULL;
                ic->i_recv_cq = NULL;
        }
        BUG_ON(ic->rds_ibdev);

        /* Clear pending transmit */
        if (ic->i_data_op) {
                struct rds_message *rm;

                rm = container_of(ic->i_data_op, struct rds_message, data);
                rds_message_put(rm);
                ic->i_data_op = NULL;
        }

        /* Clear the ACK state */
        clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
#ifdef KERNEL_HAS_ATOMIC64
        atomic64_set(&ic->i_ack_next, 0);
#else
        ic->i_ack_next = 0;
#endif
        ic->i_ack_recv = 0;

        /* Clear flow control state */
        ic->i_flowctl = 0;
        atomic_set(&ic->i_credits, 0);

        /* Re-init rings, but retain sizes. */
        rds_ib_ring_init(&ic->i_send_ring, ic->i_send_ring.w_nr);
        rds_ib_ring_init(&ic->i_recv_ring, ic->i_recv_ring.w_nr);

        if (ic->i_ibinc) {
                rds_inc_put(&ic->i_ibinc->ii_inc);
                ic->i_ibinc = NULL;
        }

        vfree(ic->i_sends);
        ic->i_sends = NULL;
        vfree(ic->i_recvs);
        ic->i_recvs = NULL;
        ic->i_active_side = false;
}

int rds_ib_conn_alloc(struct rds_connection *conn, gfp_t gfp)
{
        struct rds_ib_connection *ic;
        unsigned long flags;
        int ret;

        /* XXX too lazy? */
        ic = kzalloc(sizeof(struct rds_ib_connection), gfp);
        if (!ic)
                return -ENOMEM;

        ret = rds_ib_recv_alloc_caches(ic, gfp);
        if (ret) {
                kfree(ic);
                return ret;
        }

        INIT_LIST_HEAD(&ic->ib_node);
        tasklet_init(&ic->i_send_tasklet, rds_ib_tasklet_fn_send,
                     (unsigned long)ic);
        tasklet_init(&ic->i_recv_tasklet, rds_ib_tasklet_fn_recv,
                     (unsigned long)ic);
        mutex_init(&ic->i_recv_mutex);
#ifndef KERNEL_HAS_ATOMIC64
        spin_lock_init(&ic->i_ack_lock);
#endif
        atomic_set(&ic->i_signaled_sends, 0);
        atomic_set(&ic->i_fastreg_wrs, RDS_IB_DEFAULT_FR_WR);

        /*
         * rds_ib_conn_shutdown() waits for these to be emptied so they
         * must be initialized before it can be called.
         */
        rds_ib_ring_init(&ic->i_send_ring, 0);
        rds_ib_ring_init(&ic->i_recv_ring, 0);

        ic->conn = conn;
        conn->c_transport_data = ic;

        spin_lock_irqsave(&ib_nodev_conns_lock, flags);
        list_add_tail(&ic->ib_node, &ib_nodev_conns);
        spin_unlock_irqrestore(&ib_nodev_conns_lock, flags);


        rdsdebug("conn %p conn ic %p\n", conn, conn->c_transport_data);
        return 0;
}

/*
 * Free a connection. Connection must be shut down and not set for reconnect.
 */
void rds_ib_conn_free(void *arg)
{
        struct rds_ib_connection *ic = arg;
        spinlock_t      *lock_ptr;

        rdsdebug("ic %p\n", ic);

        /*
         * Conn is either on a dev's list or on the nodev list.
         * A race with shutdown() or connect() would cause problems
         * (since rds_ibdev would change) but that should never happen.
         */
        lock_ptr = ic->rds_ibdev ? &ic->rds_ibdev->spinlock : &ib_nodev_conns_lock;

        spin_lock_irq(lock_ptr);
        list_del(&ic->ib_node);
        spin_unlock_irq(lock_ptr);

        rds_ib_recv_free_caches(ic);

        kfree(ic);
}


/*
 * An error occurred on the connection
 */
void
__rds_ib_conn_error(struct rds_connection *conn, const char *fmt, ...)
{
        va_list ap;

        rds_conn_drop(conn);

        va_start(ap, fmt);
        vprintk(fmt, ap);
        va_end(ap);
}