rdma_read_requester_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.
 *
 */
 
#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"
 
#define MAX_BUFF_SIZE (256) /* Maximum DOCA buffer size */
 
DOCA_LOG_REGISTER(RDMA_READ_REQUESTER::SAMPLE);
 
/*
 * Write the connection details for the responder to read,
 * and read the connection details and the remote mmap details of the responder
 * 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;
 
    if (cfg->transport_type == DOCA_RDMA_TRANSPORT_TYPE_RC) {
        /* 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;
        }
 
        DOCA_LOG_INFO("You can now copy %s to the responder", cfg->local_connection_desc_path);
    }
 
    DOCA_LOG_INFO(
        "Please copy %s and %s from the responder and then press enter after pressing enter in the responder side",
        cfg->remote_connection_desc_path,
        cfg->remote_resource_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;
    }
 
    /* Read the remote mmap connection details */
    result = read_file(cfg->remote_resource_desc_path,
               (char **)&resources->remote_mmap_descriptor,
               &resources->remote_mmap_descriptor_size);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to read the remote RDMA mmap connection details: %s",
                 doca_error_get_descr(result));
        return result;
    }
 
    return result;
}
 
/*
 * RDMA read task completed callback
 *
 * @rdma_read_task [in]: Completed task
 * @task_user_data [in]: doca_data from the task
 * @ctx_user_data [in]: doca_data from the context
 */
static void rdma_read_completed_callback(struct doca_rdma_task_read *rdma_read_task,
                     union doca_data task_user_data,
                     union doca_data ctx_user_data)
{
    struct rdma_resources *resources = (struct rdma_resources *)ctx_user_data.ptr;
    void *dst_buf_data;
    doca_error_t *first_encountered_error = (doca_error_t *)task_user_data.ptr;
    doca_error_t result = DOCA_SUCCESS, tmp_result;
 
    DOCA_LOG_INFO("RDMA read task was done Successfully");
 
    /* Read the data that was read */
    result = doca_buf_get_data(resources->dst_buf, &dst_buf_data);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to get destination buffer data: %s", doca_error_get_descr(result));
        goto free_task;
    }
 
    /* Check if dst_buf_data is null terminated and of legal size */
    if (strnlen(dst_buf_data, MAX_BUFF_SIZE) == MAX_BUFF_SIZE) {
        DOCA_LOG_ERR("The message that we read from the responder exceeds buffer size %d", MAX_BUFF_SIZE);
        result = DOCA_ERROR_INVALID_VALUE;
        goto free_task;
    }
 
    DOCA_LOG_INFO("Read from responder: \"%s\"", (char *)dst_buf_data);
 
free_task:
    doca_task_free(doca_rdma_task_read_as_task(rdma_read_task));
    tmp_result = doca_buf_dec_refcount(resources->dst_buf, NULL);
    if (tmp_result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to decrease dst_buf count: %s", doca_error_get_descr(tmp_result));
        DOCA_ERROR_PROPAGATE(result, tmp_result);
    }
    tmp_result = doca_buf_dec_refcount(resources->src_buf, NULL);
    if (tmp_result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to decrease src_buf count: %s", doca_error_get_descr(tmp_result));
        DOCA_ERROR_PROPAGATE(result, tmp_result);
    }
 
    /* Update that an error was encountered, if any */
    DOCA_ERROR_PROPAGATE(*first_encountered_error, tmp_result);
 
    resources->num_remaining_tasks--;
    /* Stop context once all tasks are completed */
    if (resources->num_remaining_tasks == 0) {
        if (resources->cfg->use_rdma_cm == true)
            (void)rdma_cm_disconnect(resources);
        (void)doca_ctx_stop(resources->rdma_ctx);
    }
}
 
/*
 * RDMA read task error callback
 *
 * @rdma_read_task [in]: failed task
 * @task_user_data [in]: doca_data from the task
 * @ctx_user_data [in]: doca_data from the context
 */
static void rdma_read_error_callback(struct doca_rdma_task_read *rdma_read_task,
                     union doca_data task_user_data,
                     union doca_data ctx_user_data)
{
    struct rdma_resources *resources = (struct rdma_resources *)ctx_user_data.ptr;
    struct doca_task *task = doca_rdma_task_read_as_task(rdma_read_task);
    doca_error_t *first_encountered_error = (doca_error_t *)task_user_data.ptr;
    doca_error_t result;
 
    /* Update that an error was encountered */
    result = doca_task_get_status(task);
    DOCA_ERROR_PROPAGATE(*first_encountered_error, result);
    DOCA_LOG_ERR("RDMA read task failed: %s", doca_error_get_descr(result));
 
    doca_task_free(task);
    result = doca_buf_dec_refcount(resources->dst_buf, NULL);
    if (result != DOCA_SUCCESS)
        DOCA_LOG_ERR("Failed to decrease dst_buf count: %s", doca_error_get_descr(result));
    result = doca_buf_dec_refcount(resources->src_buf, NULL);
    if (result != DOCA_SUCCESS)
        DOCA_LOG_ERR("Failed to decrease src_buf count: %s", doca_error_get_descr(result));
 
    resources->num_remaining_tasks--;
    /* Stop context once all tasks are completed */
    if (resources->num_remaining_tasks == 0) {
        if (resources->cfg->use_rdma_cm == true)
            (void)rdma_cm_disconnect(resources);
        (void)doca_ctx_stop(resources->rdma_ctx);
    }
}
 
/*
 * 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_requester_export_and_connect(struct rdma_resources *resources)
{
    doca_error_t result;
    struct rdma_config *cfg = resources->cfg;
 
    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;
    }
 
    /* Write and read connection details from the responder */
    result = write_read_connection(resources->cfg, resources);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to write and read connection details from the responder: %s",
                 doca_error_get_descr(result));
        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 sender's RDMA to the responder's RDMA: %s",
                 doca_error_get_descr(result));
 
    return result;
}
 
/*
 * Prepare and submit RDMA read task
 *
 * @resources [in]: RDMA resources
 * @return: DOCA_SUCCESS on success and DOCA_ERROR otherwise
 */
static doca_error_t rdma_read_prepare_and_submit_task(struct rdma_resources *resources)
{
    struct doca_rdma_task_read *rdma_read_task = NULL;
    union doca_data task_user_data = {0};
    char *remote_mmap_range;
    size_t remote_mmap_range_len;
    doca_error_t result, tmp_result;
 
    /* Create remote mmap */
    result = doca_mmap_create_from_export(NULL,
                          resources->remote_mmap_descriptor,
                          resources->remote_mmap_descriptor_size,
                          resources->doca_device,
                          &(resources->remote_mmap));
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to create mmap from export: %s", doca_error_get_descr(result));
        return result;
    }
 
    /* Get the remote mmap memory range */
    result = doca_mmap_get_memrange(resources->remote_mmap, (void **)&remote_mmap_range, &remote_mmap_range_len);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to get DOCA memory map range: %s", doca_error_get_descr(result));
        return result;
    }
 
    /* Add src buffer to DOCA buffer inventory from the remote mmap */
    result = doca_buf_inventory_buf_get_by_data(resources->buf_inventory,
                            resources->remote_mmap,
                            remote_mmap_range,
                            MAX_BUFF_SIZE,
                            &resources->src_buf);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to allocate DOCA buffer to DOCA buffer inventory: %s",
                 doca_error_get_descr(result));
        return result;
    }
 
    /* Add dst buffer to DOCA buffer inventory */
    result = doca_buf_inventory_buf_get_by_addr(resources->buf_inventory,
                            resources->mmap,
                            resources->mmap_memrange,
                            MAX_BUFF_SIZE,
                            &resources->dst_buf);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to allocate DOCA buffer to DOCA buffer inventory: %s",
                 doca_error_get_descr(result));
        goto destroy_src_buf;
    }
 
    /* Include first_encountered_error in user data of task to be used in the callbacks */
    task_user_data.ptr = &(resources->first_encountered_error);
    /* Allocate and construct RDMA read task */
    result = doca_rdma_task_read_allocate_init(resources->rdma,
                           resources->connections[0],
                           resources->src_buf,
                           resources->dst_buf,
                           task_user_data,
                           &rdma_read_task);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to allocate RDMA read task: %s", doca_error_get_descr(result));
        goto destroy_dst_buf;
    }
 
    /* Submit RDMA read task */
    DOCA_LOG_INFO("Submitting RDMA read task");
    resources->num_remaining_tasks++;
    result = doca_task_submit(doca_rdma_task_read_as_task(rdma_read_task));
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to submit RDMA read task: %s", doca_error_get_descr(result));
        goto free_task;
    }
 
    return result;
 
free_task:
    doca_task_free(doca_rdma_task_read_as_task(rdma_read_task));
destroy_dst_buf:
    tmp_result = doca_buf_dec_refcount(resources->dst_buf, NULL);
    if (tmp_result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to decrease dst_buf count: %s", doca_error_get_descr(tmp_result));
        DOCA_ERROR_PROPAGATE(result, tmp_result);
    }
destroy_src_buf:
    tmp_result = doca_buf_dec_refcount(resources->src_buf, NULL);
    if (tmp_result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to decrease src_buf count: %s", doca_error_get_descr(tmp_result));
        DOCA_ERROR_PROPAGATE(result, tmp_result);
    }
    return result;
}
 
/*
 * RDMA read requester 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_requester_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_requester_export_and_connect(resources);
        if (result != DOCA_SUCCESS) {
            DOCA_LOG_ERR("rdma_read_requester_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;
 
        result = rdma_read_prepare_and_submit_task(resources);
        if (result != DOCA_SUCCESS)
            DOCA_LOG_ERR("rdma_read_prepare_and_submit_task() failed: %s", doca_error_get_descr(result));
        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);
    }
}
 
/*
 * Requester side of the RDMA read
 *
 * @cfg [in]: Configuration parameters
 * @return: DOCA_SUCCESS on success and DOCA_ERROR otherwise
 */
doca_error_t rdma_read_requester(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;
    const uint32_t rdma_permissions = DOCA_ACCESS_FLAG_LOCAL_READ_WRITE;
    struct timespec ts = {
        .tv_sec = 0,
        .tv_nsec = SLEEP_IN_NANOS,
    };
    doca_error_t result, tmp_result;
 
    /* Allocating resources */
    result = allocate_rdma_resources(cfg,
                     mmap_permissions,
                     rdma_permissions,
                     doca_rdma_cap_task_read_is_supported,
                     &resources);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to allocate RDMA Resources: %s", doca_error_get_descr(result));
        return result;
    }
 
    result = doca_rdma_task_read_set_conf(resources.rdma,
                          rdma_read_completed_callback,
                          rdma_read_error_callback,
                          NUM_RDMA_TASKS);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Unable to set configurations for RDMA read task: %s", doca_error_get_descr(result));
        goto destroy_resources;
    }
 
    result = doca_ctx_set_state_changed_cb(resources.rdma_ctx, rdma_read_requester_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;
    }
 
    /* Create DOCA buffer inventory */
    result = doca_buf_inventory_create(INVENTORY_NUM_INITIAL_ELEMENTS, &resources.buf_inventory);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to create DOCA buffer inventory: %s", doca_error_get_descr(result));
        goto destroy_resources;
    }
 
    /* Start DOCA buffer inventory */
    result = doca_buf_inventory_start(resources.buf_inventory);
    if (result != DOCA_SUCCESS) {
        DOCA_LOG_ERR("Failed to start DOCA buffer inventory: %s", doca_error_get_descr(result));
        goto destroy_buf_inventory;
    }
 
    /* Set send&recv task configuration, they are used for transferring the mmap desc */
    if (cfg->use_rdma_cm == true) {
        resources.is_requester = true;
        resources.require_remote_mmap = true;
        resources.task_fn = rdma_read_prepare_and_submit_task;
        result = config_rdma_cm_callback_and_negotiation_task(&resources,
                                      /* need_send_mmap_info */ false,
                                      /* need_recv_mmap_info */ true);
        if (result != DOCA_SUCCESS) {
            DOCA_LOG_ERR("Failed to config RDMA CM callbacks and negotiation functions: %s",
                     doca_error_get_descr(result));
            goto destroy_buf_inventory;
        }
    }
 
    /* 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 stop_buf_inventory;
    }
 
    /*
     * Run the progress engine which will run the state machine defined in
     * rdma_read_requester_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;
 
stop_buf_inventory:
    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);
    }
destroy_buf_inventory:
    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);
    }
destroy_resources:
    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;
}