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Add multithreaded example using the async API

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Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
This commit is contained in:
Ronnie Sahlberg
2025-04-26 09:21:22 +10:00
parent 31fd95dc8f
commit 7e86ed7962
2 changed files with 288 additions and 1 deletions
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2
examples/Makefile.am
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@@ -3,4 +3,4 @@ AM_CFLAGS=$(WARN_CFLAGS)
AM_LDFLAGS=-no-undefined
LIBS=../lib/libiscsi.la
noinst_PROGRAMS = iscsiclient iscsi-dd iscsi-pthreads-inq iscsi-pthreads-readloop
noinst_PROGRAMS = iscsiclient iscsi-dd iscsi-pthreads-inq iscsi-pthreads-readloop iscsi-pthreads-readloop-async

287
examples/iscsi-pthreads-readloop-async.c Normal file
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@@ -0,0 +1,287 @@
/*
Copyright (C) 2025 by Ronnie Sahlberg <ronniesahlberg@gmail.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
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
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#ifdef HAVE_POLL_H
#include <poll.h>
#endif
#include <getopt.h>
#include <inttypes.h>
#include <pthread.h>
#include <semaphore.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include "iscsi.h"
#include "scsi-lowlevel.h"
static int finished;
/*
* Number of iscsi connections to the server.
*/
#define NUM_CONTEXTS 1
/*
* Number of threads parallely read device data.
* Usually one thread per context should be sufficient, but here we use more
* threads to demonstrate that multiple threads can very well write to the same
* context.
*/
#define NUM_THREADS 4
/*
* Number of tasks per burst in each thread
*/
#define NUM_TASKS 16
const char *initiator = "iqn.2007-10.com.github:sahlberg:libiscsi:iscsi-inq";
void print_usage(void)
{
fprintf(stderr, "Usage: iscsi-pthreads-readloop [-?] [-?|--help] [--usage] [-i|--initiator-name=iqn-name]\n"
"\t\t<iscsi-url>\n");
}
void print_help(void)
{
fprintf(stderr, "Usage: iscsi-pthreads-readloop [OPTION...] <iscsi-url>\n");
fprintf(stderr, " -i, --initiator-name=iqn-name Initiatorname to use\n");
fprintf(stderr, " -d, --debug=integer debug level (0=disabled)\n");
fprintf(stderr, "\n");
fprintf(stderr, "Help options:\n");
fprintf(stderr, " -?, --help Show this help message\n");
fprintf(stderr, " --usage Display brief usage message\n");
fprintf(stderr, "\n");
fprintf(stderr, "iSCSI URL format : %s\n", ISCSI_URL_SYNTAX);
fprintf(stderr, "\n");
fprintf(stderr, "<host> is either of:\n");
fprintf(stderr, " \"hostname\" iscsi.example\n");
fprintf(stderr, " \"ipv4-address\" 10.1.1.27\n");
fprintf(stderr, " \"ipv6-address\" [fce0::1]\n");
}
struct read_data {
struct iscsi_context *iscsi;
int lun;
int i;
pthread_t thread;
sem_t sem;
};
void read_cb(struct iscsi_context *iscsi, int status, void *command_data, void *private_data)
{
struct read_data *rd = (struct read_data *)private_data;
struct scsi_task *task = command_data;
if (status == SCSI_STATUS_CHECK_CONDITION) {
fprintf(stderr, "Read10 failed with sense key:%d ascq:%04x\n", task->sense.key, task->sense.ascq);
scsi_free_scsi_task(task);
exit(10);
}
if (status != SCSI_STATUS_GOOD) {
fprintf(stderr, "Read10/16 failed with %s\n", iscsi_get_error(iscsi));
scsi_free_scsi_task(task);
exit(10);
}
sem_post(&rd->sem);
scsi_free_scsi_task(task);
}
static void *iscsi_read_thread(void *arg)
{
struct read_data *rd = arg;
struct scsi_task *task;
int i;
task = malloc(1024);
printf("iscsi_read_thread %d %p\n", rd->i, task);
free(task);
sem_init(&rd->sem, 0, 0);
while (!finished) {
for (i = 0; i < NUM_TASKS; i++) {
task = iscsi_read10_task(rd->iscsi, rd->lun, 0,
512, 512,
0, 0, 0, 0, 0,
read_cb, rd);
if (task == NULL) {
fprintf(stderr, "Failed to read from lun in thread #%d\n", rd->i);
exit(10);
}
}
for (i = 0; i < NUM_TASKS; i++) {
sem_wait(&rd->sem);
}
}
return NULL;
}
static void sig_alarm(int sig)
{
finished = 1;
}
int main(int argc, char *argv[])
{
struct iscsi_context *iscsi[NUM_CONTEXTS] = {NULL,};
char *url = NULL;
struct iscsi_url *iscsi_url = NULL;
int show_help = 0, show_usage = 0, debug = 0;
int c, i;
struct read_data *rd;
static struct option long_options[] = {
{"help", no_argument, NULL, 'h'},
{"usage", no_argument, NULL, 'u'},
{"debug", required_argument, NULL, 'd'},
{"initiator-name", required_argument, NULL, 'i'},
{0, 0, 0, 0}
};
int option_index;
while ((c = getopt_long(argc, argv, "h?ud:i:e:c:", long_options,
&option_index)) != -1) {
switch (c) {
case 'h':
case '?':
show_help = 1;
break;
case 'u':
show_usage = 1;
break;
case 'd':
debug = strtol(optarg, NULL, 0);
break;
case 'i':
initiator = optarg;
break;
default:
fprintf(stderr, "Unrecognized option '%c'\n\n", c);
print_help();
exit(0);
}
}
if (show_help != 0) {
print_help();
exit(0);
}
if (show_usage != 0) {
print_usage();
exit(0);
}
for (i = 0; i < NUM_CONTEXTS; i++) {
printf("Creating context #%d\n", i);
iscsi[i] = iscsi_create_context(initiator);
if (iscsi[i] == NULL) {
fprintf(stderr, "Failed to create context\n");
exit(10);
}
if (debug > 0) {
iscsi_set_log_level(iscsi[i], debug);
iscsi_set_log_fn(iscsi[i], iscsi_log_to_stderr);
}
if (i > 0) {
iscsi_destroy_url(iscsi_url);
}
if (argv[optind] != NULL) {
url = strdup(argv[optind]);
}
if (url == NULL) {
fprintf(stderr, "You must specify the URL\n");
print_usage();
exit(10);
}
iscsi_url = iscsi_parse_full_url(iscsi[i], url);
free(url);
if (iscsi_url == NULL) {
fprintf(stderr, "Failed to parse URL: %s\n",
iscsi_get_error(iscsi[i]));
exit(10);
}
iscsi_set_session_type(iscsi[i], ISCSI_SESSION_NORMAL);
iscsi_set_header_digest(iscsi[i], ISCSI_HEADER_DIGEST_NONE_CRC32C);
if (iscsi_full_connect_sync(iscsi[i], iscsi_url->portal, iscsi_url->lun) != 0) {
fprintf(stderr, "Login Failed. %s\n", iscsi_get_error(iscsi[i]));
iscsi_destroy_url(iscsi_url);
iscsi_destroy_context(iscsi[i]);
exit(10);
}
if (iscsi_mt_service_thread_start(iscsi[i])) {
fprintf(stderr, "failed to start service thread #%d\n", i);
exit(10);
}
}
if ((rd = malloc(sizeof(struct read_data) * NUM_THREADS)) == NULL) {
fprintf(stderr, "Failed to allocated read_data\n");
exit(10);
}
for (i = 0; i < NUM_THREADS; i++) {
rd[i].iscsi = iscsi[i % NUM_CONTEXTS];
rd[i].lun = iscsi_url->lun;
rd[i].i = i;
if (pthread_create(&rd[i].thread, NULL,
&iscsi_read_thread, &rd[i])) {
printf("Failed to create read thread #%d\n", i);
exit(10);
}
}
/* run for 5 seconds */
signal(SIGALRM, sig_alarm);
alarm(5);
/*
* Wait for all threads to complete
*/
for (i = 0; i < NUM_THREADS; i++) {
pthread_join(rd[i].thread, NULL);
}
iscsi_destroy_url(iscsi_url);
for (i = 0; i < NUM_CONTEXTS; i++) {
iscsi_mt_service_thread_stop(iscsi[i]);
iscsi_logout_sync(iscsi[i]);
iscsi_destroy_context(iscsi[i]);
}
printf("finished\n");
return 0;
}