[dpdk-dev] [RFC PATCH 5/5] virtio: Extend virtio-net PMD to support container environment

[Xie, Huawei]

On 1/21/2016 7:09 PM, Tetsuya Mukawa wrote:
[snip]
> +
> +static int
> +qtest_raw_recv(int fd, char *buf, size_t count)
> +{
> +	size_t len = count;
> +	size_t total_len = 0;
> +	int ret = 0;
> +
> +	while (len > 0) {
> +		ret = read(fd, buf, len);
> +		if (ret == (int)len)
> +			break;
> +		if (*(buf + ret - 1) == '\n')
> +			break;

The above two lines should be put after the below if block.

> +		if (ret == -1) {
> +			if (errno == EINTR)
> +				continue;
> +			return ret;
> +		}
> +		total_len += ret;
> +		buf += ret;
> +		len -= ret;
> +	}
> +	return total_len + ret;
> +}
> +

[snip]

> +
> +static void
> +qtest_handle_one_message(struct qtest_session *s, char *buf)
> +{
> +	int ret;
> +
> +	if (strncmp(buf, interrupt_message, strlen(interrupt_message)) == 0) {
> +		if (rte_atomic16_read(&s->enable_intr) == 0)
> +			return;
> +
> +		/* relay interrupt to pipe */
> +		ret = write(s->irqfds.writefd, "1", 1);
> +		if (ret < 0)
> +			rte_panic("cannot relay interrupt\n");
> +	} else {
> +		/* relay normal message to pipe */
> +		ret = qtest_raw_send(s->msgfds.writefd, buf, strlen(buf));
> +		if (ret < 0)
> +			rte_panic("cannot relay normal message\n");
> +	}
> +}
> +
> +static char *
> +qtest_get_next_message(char *p)
> +{
> +	p = strchr(p, '\n');
> +	if ((p == NULL) || (*(p + 1) == '\0'))
> +		return NULL;
> +	return p + 1;
> +}
> +
> +static void
> +qtest_close_one_socket(int *fd)
> +{
> +	if (*fd > 0) {
> +		close(*fd);
> +		*fd = -1;
> +	}
> +}
> +
> +static void
> +qtest_close_sockets(struct qtest_session *s)
> +{
> +	qtest_close_one_socket(&s->qtest_socket);
> +	qtest_close_one_socket(&s->msgfds.readfd);
> +	qtest_close_one_socket(&s->msgfds.writefd);
> +	qtest_close_one_socket(&s->irqfds.readfd);
> +	qtest_close_one_socket(&s->irqfds.writefd);
> +	qtest_close_one_socket(&s->ivshmem_socket);
> +}
> +
> +/*
> + * This thread relays QTest response using pipe.
> + * The function is needed because we need to separate IRQ message from others.
> + */
> +static void *
> +qtest_event_handler(void *data) {
> +	struct qtest_session *s = (struct qtest_session *)data;
> +	char buf[1024];
> +	char *p;
> +	int ret;
> +
> +	for (;;) {
> +		memset(buf, 0, sizeof(buf));
> +		ret = qtest_raw_recv(s->qtest_socket, buf, sizeof(buf));
> +		if (ret < 0) {
> +			qtest_close_sockets(s);
> +			return NULL;
> +		}
> +
> +		/* may receive multiple messages at the same time */

>From the qtest_raw_recv implementation, if at some point one message is
received by two qtest_raw_recv calls, then is that message discarded?
We could save the last incomplete message in buffer, and combine the
message received next time together.

> +		p = buf;
> +		do {
> +			qtest_handle_one_message(s, p);
> +		} while ((p = qtest_get_next_message(p)) != NULL);
> +	}
> +	return NULL;
> +}
> +