linux-kernel - Re: [RFC PATCH v1 3/3] test/vsock: skbuff merging test

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Message-ID: <20230320153132.o3xvwxmn3722lin4@sgarzare-redhat>
Date:   Mon, 20 Mar 2023 16:31:32 +0100
From:   Stefano Garzarella <sgarzare@...hat.com>
To:     Arseniy Krasnov <avkrasnov@...rdevices.ru>
Cc:     Stefan Hajnoczi <stefanha@...hat.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Bobby Eshleman <bobby.eshleman@...edance.com>,
        kvm@...r.kernel.org, virtualization@...ts.linux-foundation.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel@...rdevices.ru, oxffffaa@...il.com
Subject: Re: [RFC PATCH v1 3/3] test/vsock: skbuff merging test

On Sun, Mar 19, 2023 at 09:53:54PM +0300, Arseniy Krasnov wrote:
>This adds test which checks case when data of newly received skbuff is
>appended to the last skbuff in the socket's queue.
>
>This test is actual only for virtio transport.
>
>Signed-off-by: Arseniy Krasnov <AVKrasnov@...rdevices.ru>
>---
> tools/testing/vsock/vsock_test.c | 81 ++++++++++++++++++++++++++++++++
> 1 file changed, 81 insertions(+)
>
>diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c
>index 3de10dbb50f5..00216c52d8b6 100644
>--- a/tools/testing/vsock/vsock_test.c
>+++ b/tools/testing/vsock/vsock_test.c
>@@ -968,6 +968,82 @@ static void test_seqpacket_inv_buf_server(const struct test_opts *opts)
> 	test_inv_buf_server(opts, false);
> }
>
>+static void test_stream_virtio_skb_merge_client(const struct test_opts *opts)
>+{
>+	ssize_t res;
>+	int fd;
>+
>+	fd = vsock_stream_connect(opts->peer_cid, 1234);
>+	if (fd < 0) {
>+		perror("connect");
>+		exit(EXIT_FAILURE);
>+	}
>+

Please use a macro for "HELLO" or a variabile, e.g.

         char *buf;
         ...

         buf = "HELLO";
         res = send(fd, buf, strlen(buf), 0);
         ...

>+	res = send(fd, "HELLO", strlen("HELLO"), 0);
>+	if (res != strlen("HELLO")) {
>+		fprintf(stderr, "unexpected send(2) result %zi\n", res);
>+		exit(EXIT_FAILURE);
>+	}
>+
>+	control_writeln("SEND0");
>+	/* Peer reads part of first packet. */
>+	control_expectln("REPLY0");
>+
>+	/* Send second skbuff, it will be merged. */
>+	res = send(fd, "WORLD", strlen("WORLD"), 0);

Ditto.

>+	if (res != strlen("WORLD")) {
>+		fprintf(stderr, "unexpected send(2) result %zi\n", res);
>+		exit(EXIT_FAILURE);
>+	}
>+
>+	control_writeln("SEND1");
>+	/* Peer reads merged skbuff packet. */
>+	control_expectln("REPLY1");
>+
>+	close(fd);
>+}
>+
>+static void test_stream_virtio_skb_merge_server(const struct test_opts *opts)
>+{
>+	unsigned char buf[64];
>+	ssize_t res;
>+	int fd;
>+
>+	fd = vsock_stream_accept(VMADDR_CID_ANY, 1234, NULL);
>+	if (fd < 0) {
>+		perror("accept");
>+		exit(EXIT_FAILURE);
>+	}
>+
>+	control_expectln("SEND0");
>+
>+	/* Read skbuff partially. */
>+	res = recv(fd, buf, 2, 0);
>+	if (res != 2) {
>+		fprintf(stderr, "expected recv(2) failure, got %zi\n", res);

We don't expect a failure, so please update the error message and make
it easy to figure out which recv() is failing. For example by saying
how many bytes you expected and how many you received.

>+		exit(EXIT_FAILURE);
>+	}
>+
>+	control_writeln("REPLY0");
>+	control_expectln("SEND1");
>+
>+
>+	res = recv(fd, buf, sizeof(buf), 0);

Perhaps a comment here to explain why we expect only 8 bytes.

>+	if (res != 8) {
>+		fprintf(stderr, "expected recv(2) failure, got %zi\n", res);

Ditto.

>+		exit(EXIT_FAILURE);
>+	}
>+
>+	res = recv(fd, buf, sizeof(buf), MSG_DONTWAIT);
>+	if (res != -1) {
>+		fprintf(stderr, "expected recv(2) success, got %zi\n", res);

It's the other way around, isn't it?
Here you expect it to fail instead it is not failing.

>+		exit(EXIT_FAILURE);
>+	}

Moving the pointer correctly, I would also check that there is
HELLOWORLD in the buffer.

Thanks for adding tests in this suite!
Stefano

>+
>+	control_writeln("REPLY1");
>+
>+	close(fd);
>+}
>+
> static struct test_case test_cases[] = {
> 	{
> 		.name = "SOCK_STREAM connection reset",
>@@ -1038,6 +1114,11 @@ static struct test_case test_cases[] = {
> 		.run_client = test_seqpacket_inv_buf_client,
> 		.run_server = test_seqpacket_inv_buf_server,
> 	},
>+	{
>+		.name = "SOCK_STREAM virtio skb merge",
>+		.run_client = test_stream_virtio_skb_merge_client,
>+		.run_server = test_stream_virtio_skb_merge_server,
>+	},
> 	{},
> };
>
>-- 
>2.25.1
>