Add pthreads to the iou-zcrx client so that multiple connections can be
established simultaneously. Each client thread connects to the server
and sends its payload independently.

Introduce struct thread_ctx and the -t option to control the number of
threads (default 1), preserving backwards compatibility with existing
tests.

Signed-off-by: Juanlu Herrero <juanlu@fastmail.com>
---
 .../testing/selftests/drivers/net/hw/Makefile |  2 +-
 .../selftests/drivers/net/hw/iou-zcrx.c       | 46 +++++++++++++++++--
 2 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/Makefile b/tools/testing/selftests/drivers/net/hw/Makefile
index deeca3f8d080..227adfec706c 100644
--- a/tools/testing/selftests/drivers/net/hw/Makefile
+++ b/tools/testing/selftests/drivers/net/hw/Makefile
@@ -80,5 +80,5 @@ include ../../../net/ynl.mk
 include ../../../net/bpf.mk
 
 ifeq ($(HAS_IOURING_ZCRX),y)
-$(OUTPUT)/iou-zcrx: LDLIBS += -luring
+$(OUTPUT)/iou-zcrx: LDLIBS += -luring -lpthread
 endif
diff --git a/tools/testing/selftests/drivers/net/hw/iou-zcrx.c b/tools/testing/selftests/drivers/net/hw/iou-zcrx.c
index 334985083f61..de2eea78a5b6 100644
--- a/tools/testing/selftests/drivers/net/hw/iou-zcrx.c
+++ b/tools/testing/selftests/drivers/net/hw/iou-zcrx.c
@@ -4,6 +4,7 @@
 #include <error.h>
 #include <fcntl.h>
 #include <limits.h>
+#include <pthread.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -85,8 +86,14 @@ static int cfg_send_size = SEND_SIZE;
 static struct sockaddr_in6 cfg_addr;
 static unsigned int cfg_rx_buf_len;
 static bool cfg_dry_run;
+static int cfg_num_threads = 1;
 
 static char *payload;
+
+struct thread_ctx {
+	int			thread_id;
+};
+
 static void *area_ptr;
 static void *ring_ptr;
 static size_t ring_size;
@@ -376,7 +383,7 @@ static void run_server(void)
 		error(1, 0, "test failed\n");
 }
 
-static void run_client(void)
+static void *client_worker(void *arg)
 {
 	ssize_t to_send = cfg_send_size;
 	ssize_t sent = 0;
@@ -402,12 +409,42 @@ static void run_client(void)
 	}
 
 	close(fd);
+	return NULL;
+}
+
+static void run_client(void)
+{
+	struct thread_ctx *ctxs;
+	pthread_t *threads;
+	int i, ret;
+
+	ctxs = calloc(cfg_num_threads, sizeof(*ctxs));
+	threads = calloc(cfg_num_threads, sizeof(*threads));
+	if (!ctxs || !threads)
+		error(1, 0, "calloc()");
+
+	for (i = 0; i < cfg_num_threads; i++)
+		ctxs[i].thread_id = i;
+
+	for (i = 0; i < cfg_num_threads; i++) {
+		ret = pthread_create(&threads[i], NULL, client_worker,
+				     &ctxs[i]);
+		if (ret)
+			error(1, ret, "pthread_create()");
+	}
+
+	for (i = 0; i < cfg_num_threads; i++)
+		pthread_join(threads[i], NULL);
+
+	free(threads);
+	free(ctxs);
 }
 
 static void usage(const char *filepath)
 {
 	error(1, 0, "Usage: %s (-4|-6) (-s|-c) -h<server_ip> -p<port> "
-		    "-l<payload_size> -i<ifname> -q<rxq_id>", filepath);
+		    "-l<payload_size> -i<ifname> -q<rxq_id> -t<num_threads>",
+		    filepath);
 }
 
 static void parse_opts(int argc, char **argv)
@@ -425,7 +462,7 @@ static void parse_opts(int argc, char **argv)
 		usage(argv[0]);
 	cfg_payload_len = max_payload_len;
 
-	while ((c = getopt(argc, argv, "sch:p:l:i:q:o:z:x:d")) != -1) {
+	while ((c = getopt(argc, argv, "sch:p:l:i:q:o:z:x:dt:")) != -1) {
 		switch (c) {
 		case 's':
 			if (cfg_client)
@@ -466,6 +503,9 @@ static void parse_opts(int argc, char **argv)
 		case 'd':
 			cfg_dry_run = true;
 			break;
+		case 't':
+			cfg_num_threads = strtoul(optarg, NULL, 0);
+			break;
 		}
 	}
 
-- 
2.53.0