Re: [RFC PATCH v1 3/3] vsock_test: POLLIN + SO_RCVLOWAT test.

[Stefano Garzarella <sgarzare@redhat.com>]

On Mon, Jul 18, 2022 at 08:19:06AM +0000, Arseniy Krasnov wrote:
>This adds test to check, that when poll() returns POLLIN and
>POLLRDNORM bits, next read call won't block.
>
>Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>---
> tools/testing/vsock/vsock_test.c | 90 ++++++++++++++++++++++++++++++++
> 1 file changed, 90 insertions(+)
>
>diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c
>index dc577461afc2..8e394443eaf6 100644
>--- a/tools/testing/vsock/vsock_test.c
>+++ b/tools/testing/vsock/vsock_test.c
>@@ -18,6 +18,7 @@
> #include <sys/socket.h>
> #include <time.h>
> #include <sys/mman.h>
>+#include <poll.h>
>
> #include "timeout.h"
> #include "control.h"
>@@ -596,6 +597,90 @@ static void test_seqpacket_invalid_rec_buffer_server(const struct test_opts *opt
> 	close(fd);
> }
>
>+static void test_stream_poll_rcvlowat_server(const struct test_opts *opts)
>+{
>+#define RCVLOWAT_BUF_SIZE 128
>+	int fd;
>+	int i;
>+
>+	fd = vsock_stream_accept(VMADDR_CID_ANY, 1234, NULL);
>+	if (fd < 0) {
>+		perror("accept");
>+		exit(EXIT_FAILURE);
>+	}
>+
>+	/* Send 1 byte. */
>+	send_byte(fd, 1, 0);
>+
>+	control_writeln("SRVSENT");
>+
>+	/* Just empirically delay value. */
>+	sleep(4);

Why we need this sleep()?