rdma_read_responder_sample.c

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/*
 * Copyright (c) 2023 NVIDIA CORPORATION AND AFFILIATES.  All rights reserved.
 *
 * 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.
 *     * Neither the name of the NVIDIA CORPORATION nor the names of its contributors may be used
 *       to endorse or promote products derived from this software without specific prior written
 *       permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NVIDIA CORPORATION BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TOR (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
 
#include <doca_error.h>
#include <doca_log.h>
#include <doca_buf_inventory.h>
#include <doca_buf.h>
#include <doca_ctx.h>
 
#include "rdma_common.h"
 
DOCA_LOG_REGISTER(RDMA_READ_RESPONDER::SAMPLE);
 
/*
 * Write the connection details and the mmap details for the requester to read,
 * and read the connection details of the requester
 * In DC transport mode it is only needed to read the remote connection details
 *
 * @cfg [in]: Configuration parameters
 * @resources [in/out]: RDMA resources
 * @return: DOCA_SUCCESS on success and DOCA_ERROR otherwise
 */
static doca_error_t write_read_connection(struct rdma_config *cfg, struct rdma_resources *resources)
{
    doca_error_t result = DOCA_SUCCESS;
 
    /* Write the RDMA connection details */
    result = write_file(cfg->local_connection_desc_path,
                (char *)resources->rdma_conn_descriptor,
                resources->rdma_conn_descriptor_size);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to write the RDMA connection details: %s", doca_error_get_descr(result));
        return result;
    }
 
    /* Write the RDMA connection details */
    result = write_file(cfg->remote_resource_desc_path,
                (char *)resources->mmap_descriptor,
                resources->mmap_descriptor_size);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to write the RDMA mmap details: %s", doca_error_get_descr(result));
        return result;
    }
 
    DOCA_LOG_INFO("You can now copy %s and %s to the requester",
              cfg->local_connection_desc_path,
              cfg->remote_resource_desc_path);
 
    if (cfg->transport_type == DOCA_RDMA_TRANSPORT_TYPE_DC) {
        return result;
    }
 
    DOCA_LOG_INFO("Please copy %s from the requester and then press enter", cfg->remote_connection_desc_path);
 
    /* Wait for enter */
    wait_for_enter();
 
    /* Read the remote RDMA connection details */
    result = read_file(cfg->remote_connection_desc_path,
               (char **)&resources->remote_rdma_conn_descriptor,
               &resources->remote_rdma_conn_descriptor_size);
    if (result != DOCA_SUCCESS)
        DOCA_LOG_ERR("Failed to read the remote RDMA connection details: %s", doca_error_get_descr(result));
 
    return result;
}
 
/*
 * Export and receive connection details, and connect to the remote RDMA
 *
 * @resources [in]: RDMA resources
 * @return: DOCA_SUCCESS on success and DOCA_ERROR otherwise
 */
static doca_error_t rdma_read_responder_export_and_connect(struct rdma_resources *resources)
{
    size_t read_string_len = strlen(resources->cfg->read_string) + 1;
    struct rdma_config *cfg = resources->cfg;
    doca_error_t result;
 
    if (cfg->use_rdma_cm == true)
        return rdma_cm_connect(resources);
 
    /* Export RDMA connection details */
    result = doca_rdma_export(resources->rdma,
                  &(resources->rdma_conn_descriptor),
                  &(resources->rdma_conn_descriptor_size),
                  &(resources->connections[0]));
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to export RDMA: %s", doca_error_get_descr(result));
        return result;
    }
 
    /* Copy the read string to the mmap memory range */
    strncpy(resources->mmap_memrange, resources->cfg->read_string, read_string_len);
 
    /* Export RDMA mmap */
    result = doca_mmap_export_rdma(resources->mmap,
                       resources->doca_device,
                       (const void **)&(resources->mmap_descriptor),
                       &(resources->mmap_descriptor_size));
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to export DOCA mmap for RDMA: %s", doca_error_get_descr(result));
        return result;
    }
 
    /* write and read connection details from the requester */
    result = write_read_connection(resources->cfg, resources);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to write and read connection details from the requester: %s",
                 doca_error_get_descr(result));
        return result;
    }
 
    if (cfg->transport_type == DOCA_RDMA_TRANSPORT_TYPE_DC) {
        return result;
    }
    /* Connect RDMA */
    result = doca_rdma_connect(resources->rdma,
                   resources->remote_rdma_conn_descriptor,
                   resources->remote_rdma_conn_descriptor_size,
                   resources->connections[0]);
    if (result != DOCA_SUCCESS)
        DOCA_LOG_ERR("Failed to connect the responder's RDMA to the requester's RDMA: %s",
                 doca_error_get_descr(result));
 
    return result;
}
 
/*
 * RDMA read responder state change callback
 * This function represents the state machine for this RDMA program
 *
 * @user_data [in]: doca_data from the context
 * @ctx [in]: DOCA context
 * @prev_state [in]: Previous DOCA context state
 * @next_state [in]: Next DOCA context state
 */
static void rdma_read_responder_state_change_callback(const union doca_data user_data,
                              struct doca_ctx *ctx,
                              enum doca_ctx_states prev_state,
                              enum doca_ctx_states next_state)
{
    struct rdma_resources *resources = (struct rdma_resources *)user_data.ptr;
    struct rdma_config *cfg = resources->cfg;
    doca_error_t result = DOCA_SUCCESS;
    (void)prev_state;
 
    switch (next_state) {
    case DOCA_CTX_STATE_STARTING:
        DOCA_LOG_INFO("RDMA context entered starting state");
        break;
    case DOCA_CTX_STATE_RUNNING:
        DOCA_LOG_INFO("RDMA context is running");
 
        result = rdma_read_responder_export_and_connect(resources);
        if (result != DOCA_SUCCESS) {
            DOCA_LOG_ERR("rdma_read_responder_export_and_connect() failed: %s",
                     doca_error_get_descr(result));
            break;
        } else
            DOCA_LOG_INFO("RDMA context finished initialization");
 
        if (cfg->use_rdma_cm == true)
            break;
 
        /* Wait for enter which means that the requester has finished reading */
        DOCA_LOG_INFO("Wait till the requester has finished reading and press enter");
        wait_for_enter();
 
        /* Stop context */
        (void)doca_ctx_stop(resources->rdma_ctx);
        break;
    case DOCA_CTX_STATE_STOPPING:
        DOCA_LOG_INFO("RDMA context entered into stopping state. Any inflight tasks will be flushed");
        break;
    case DOCA_CTX_STATE_IDLE:
        DOCA_LOG_INFO("RDMA context has been stopped");
 
        /* We can stop progressing the PE */
        resources->run_pe_progress = false;
        break;
    default:
        break;
    }
 
    /* If something failed - update that an error was encountered and stop the ctx */
    if (result != DOCA_SUCCESS) {
        DOCA_ERROR_PROPAGATE(resources->first_encountered_error, result);
        (void)doca_ctx_stop(ctx);
    }
}
 
/*
 * Responder wait for requester to finish
 *
 * @resources [in]: RDMA resources
 * @return: DOCA_SUCCESS on success and DOCA_ERROR otherwise
 */
static doca_error_t responder_wait_for_requester_finish(struct rdma_resources *resources)
{
    doca_error_t result;
 
    DOCA_LOG_INFO("Wait till the requester has finished reading and press enter");
    wait_for_enter();
 
    if (resources->cfg->use_rdma_cm == true) {
        result = rdma_cm_disconnect(resources);
        if (result != DOCA_SUCCESS) {
            DOCA_LOG_ERR("Failed to disconnect RDMA connection: %s", doca_error_get_descr(result));
            return result;
        }
    }
 
    (void)doca_ctx_stop(resources->rdma_ctx);
    return DOCA_SUCCESS;
}
 
/*
 * Responder side of the RDMA read
 *
 * @cfg [in]: Configuration parameters
 * @return: DOCA_SUCCESS on success and DOCA_ERROR otherwise
 */
doca_error_t rdma_read_responder(struct rdma_config *cfg)
{
    struct rdma_resources resources = {0};
    union doca_data ctx_user_data = {0};
    const uint32_t mmap_permissions = DOCA_ACCESS_FLAG_LOCAL_READ_WRITE | DOCA_ACCESS_FLAG_RDMA_READ;
    const uint32_t rdma_permissions = DOCA_ACCESS_FLAG_RDMA_READ;
    doca_error_t result, tmp_result;
    struct timespec ts = {
        .tv_sec = 0,
        .tv_nsec = SLEEP_IN_NANOS,
    };
 
    /* Allocating resources */
    result = allocate_rdma_resources(cfg, mmap_permissions, rdma_permissions, NULL, &resources);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to allocate RDMA Resources: %s", doca_error_get_descr(result));
        return result;
    }
 
    result = doca_ctx_set_state_changed_cb(resources.rdma_ctx, rdma_read_responder_state_change_callback);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Unable to set state change callback for RDMA context: %s", doca_error_get_descr(result));
        goto destroy_resources;
    }
 
    /* Include the program's resources in user data of context to be used in callbacks */
    ctx_user_data.ptr = &(resources);
    result = doca_ctx_set_user_data(resources.rdma_ctx, ctx_user_data);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to set context user data: %s", doca_error_get_descr(result));
        goto destroy_resources;
    }
 
    if (cfg->use_rdma_cm == true) {
        resources.is_requester = false;
        resources.require_remote_mmap = true;
        resources.task_fn = responder_wait_for_requester_finish;
        /* Copy the read string to the mmap memory range */
        memset(resources.mmap_memrange, 0, strlen(resources.cfg->read_string) + 1);
        strcpy(resources.mmap_memrange, resources.cfg->read_string);
 
        result = config_rdma_cm_callback_and_negotiation_task(&resources,
                                      /* need_send_mmap_info */ true,
                                      /* need_recv_mmap_info */ false);
        if (result != DOCA_SUCCESS) {
            DOCA_LOG_ERR("Failed to config RDMA CM callbacks and negotiation functions: %s",
                     doca_error_get_descr(result));
            goto destroy_resources;
        }
    }
 
    /* Start RDMA context */
    result = doca_ctx_start(resources.rdma_ctx);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to start RDMA context: %s", doca_error_get_descr(result));
        goto destroy_resources;
    }
 
    /*
     * Run the progress engine which will run the state machine defined in
     * rdma_read_responder_state_change_callback() When the context moves to idle, the context change callback call
     * will signal to stop running the progress engine.
     */
    while (resources.run_pe_progress) {
        if (doca_pe_progress(resources.pe) == 0)
            nanosleep(&ts, &ts);
    }
 
    /* Assign the result we update in the callbacks */
    result = resources.first_encountered_error;
 
destroy_resources:
    if (resources.buf_inventory != NULL) {
        tmp_result = doca_buf_inventory_stop(resources.buf_inventory);
        if (tmp_result != DOCA_SUCCESS) {
            DOCA_LOG_ERR("Failed to stop DOCA buffer inventory: %s", doca_error_get_descr(tmp_result));
            DOCA_ERROR_PROPAGATE(result, tmp_result);
        }
        tmp_result = doca_buf_inventory_destroy(resources.buf_inventory);
        if (tmp_result != DOCA_SUCCESS) {
            DOCA_LOG_ERR("Failed to destroy DOCA buffer inventory: %s", doca_error_get_descr(tmp_result));
            DOCA_ERROR_PROPAGATE(result, tmp_result);
        }
    }
    tmp_result = destroy_rdma_resources(&resources, cfg);
    if (tmp_result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to destroy DOCA RDMA resources: %s", doca_error_get_descr(tmp_result));
        DOCA_ERROR_PROPAGATE(result, tmp_result);
    }
    return result;
}