要在不使用连接管理器的情况下跳过rdma_create_event_channel()，可以直接使用原始的RDMA库函数来创建和管理RDMA连接。以下是一个示例代码，演示了如何使用RDMA库函数进行连接的建立和管理。

#include 
#include 
#include 
#include 
#include 

#define IB_DEVICE_NAME "ib0"
#define IB_PORT_NUM 1
#define BUFFER_SIZE 1024

struct ib_connection {
    struct ibv_context *context;
    struct ibv_pd *pd;
    struct ibv_mr *mr;
    struct ibv_cq *cq;
    struct ibv_qp *qp;
    struct ibv_port_attr port_attr;
    char *buffer;
};

void create_qp(struct ib_connection *conn) {
    struct ibv_qp_init_attr qp_init_attr;
    memset(&qp_init_attr, 0, sizeof(qp_init_attr));
    
    qp_init_attr.send_cq = conn->cq;
    qp_init_attr.recv_cq = conn->cq;
    qp_init_attr.qp_type = IBV_QPT_RC;
    qp_init_attr.cap.max_send_wr = 10;
    qp_init_attr.cap.max_recv_wr = 10;
    qp_init_attr.cap.max_send_sge = 1;
    qp_init_attr.cap.max_recv_sge = 1;
    
    conn->qp = ibv_create_qp(conn->pd, &qp_init_attr);
    if (!conn->qp) {
        fprintf(stderr, "Failed to create QP\n");
        exit(1);
    }
}

void modify_qp_to_init(struct ib_connection *conn) {
    struct ibv_qp_attr qp_attr;
    memset(&qp_attr, 0, sizeof(qp_attr));
    
    qp_attr.qp_state = IBV_QPS_INIT;
    qp_attr.port_num = IB_PORT_NUM;
    qp_attr.pkey_index = 0;
    qp_attr.qp_access_flags = IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE;
    
    if (ibv_modify_qp(conn->qp, &qp_attr, IBV_QP_STATE | IBV_QP_PORT | IBV_QP_PKEY_INDEX | IBV_QP_ACCESS_FLAGS) != 0) {
        fprintf(stderr, "Failed to modify QP to INIT state\n");
        exit(1);
    }
}

void modify_qp_to_rtr(struct ib_connection *conn, struct ibv_gid *remote_gid, uint32_t remote_qpn, uint16_t remote_lid) {
    struct ibv_qp_attr qp_attr;
    memset(&qp_attr, 0, sizeof(qp_attr));
    
    qp_attr.qp_state = IBV_QPS_RTR;
    qp_attr.path_mtu = IBV_MTU_2048;
    qp_attr.dest_qp_num = remote_qpn;
    qp_attr.rq_psn = 0;
    qp_attr.max_dest_rd_atomic = 1;
    qp_attr.min_rnr_timer = 12;
    qp_attr.ah_attr.is_global = 1;
    qp_attr.ah_attr.dlid = remote_lid;
    qp_attr.ah_attr.sl = 0;
    qp_attr.ah_attr.src_path_bits = 0;
    qp_attr.ah_attr.port_num = IB_PORT_NUM;
    
    if (ibv_modify_qp(conn->qp, &qp_attr, IBV_QP_STATE | IBV_QP_AV | IBV_QP_PATH_MTU | IBV_QP_DEST_QPN | IBV_QP_RQ_PSN | IBV_QP_MAX_DEST_RD_ATOMIC | IBV_QP_MIN_RNR_TIMER) != 0) {
        fprintf(stderr, "Failed to modify QP to RTR state\n");
        exit(1);
    }
}

void modify_qp_to_rts(struct ib_connection *conn) {
    struct ibv_qp_attr qp_attr;
    memset(&qp_attr, 0, sizeof(qp_attr));
    
    qp_attr.qp_state = IBV_QPS_RTS;
    qp_attr.sq_psn = 0;
    qp_attr.timeout = 14;
    qp_attr.retry_cnt = 7;
    qp_attr.rnr_retry = 7;
    qp_attr.max_rd_atomic = 1;
    
    if (ibv_modify_qp(conn->qp, &qp_attr, IBV_QP_STATE | IBV_QP_SQ_PSN | IBV_QP_TIMEOUT | IBV_QP_RETRY_CNT | IBV_QP_RNR_RETRY | IBV_QP_MAX_QP_RD_ATOMIC) != 0) {
        fprintf(stderr, "Failed to modify QP to RTS state\n");
        exit(1);
    }
}

void connect