Hi Maxime,
> -----Original Message-----
> From: Maxime Coquelin <maxime.coque...@redhat.com>
> Sent: Monday, December 21, 2020 5:14 AM
> To: dev@dpdk.org; Xia, Chenbo <chenbo....@intel.com>; olivier.m...@6wind.com;
> amore...@redhat.com; david.march...@redhat.com
> Cc: Maxime Coquelin <maxime.coque...@redhat.com>
> Subject: [PATCH 35/40] net/virtio: make server mode blocking
>
> This patch makes the Vhost-user backend server mode
> blocking at init, waiting for the client connection.
>
> The goal is to make the driver more reliable, as without
> waiting for client connection, the Virtio driver has to
> assume the Vhost-user backend will support all the
> features it has advertized, which could lead to undefined
> behaviour.
>
> For example, without this patch, if the user enables packed
> ring Virtio feature but the backend does not support it,
> the ring initialized by the driver will not be compatible
> with the backend.
>
> Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
> ---
> drivers/net/virtio/virtio_user/vhost_user.c | 9 +-
> .../net/virtio/virtio_user/virtio_user_dev.c | 118 +++++++-----------
> drivers/net/virtio/virtio_user_ethdev.c | 5 -
> 3 files changed, 54 insertions(+), 78 deletions(-)
>
> diff --git a/drivers/net/virtio/virtio_user/vhost_user.c
> b/drivers/net/virtio/virtio_user/vhost_user.c
> index a57106a468..94a33326ae 100644
> --- a/drivers/net/virtio/virtio_user/vhost_user.c
> +++ b/drivers/net/virtio/virtio_user/vhost_user.c
> @@ -677,6 +677,14 @@ virtio_user_start_server(struct virtio_user_dev *dev,
> struct sockaddr_un *un)
> if (ret < 0)
> return -1;
>
> + PMD_DRV_LOG(NOTICE, "(%s) waiting for client connection...", dev->path);
> + dev->vhostfd = accept(fd, NULL, NULL);
> + if (dev->vhostfd < 0) {
> + PMD_DRV_LOG(ERR, "Failed to accept initial client connection
> (%s)",
> + strerror(errno));
> + return -1;
> + }
> +
> flag = fcntl(fd, F_GETFL);
> if (fcntl(fd, F_SETFL, flag | O_NONBLOCK) < 0) {
> PMD_DRV_LOG(ERR, "fcntl failed, %s", strerror(errno));
> @@ -721,7 +729,6 @@ vhost_user_setup(struct virtio_user_dev *dev)
> close(fd);
> return -1;
> }
> - dev->vhostfd = -1;
> } else {
> if (connect(fd, (struct sockaddr *)&un, sizeof(un)) < 0) {
> PMD_DRV_LOG(ERR, "connect error, %s", strerror(errno));
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> index b92b7f7aae..19d59d401e 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> @@ -144,10 +144,6 @@ virtio_user_dev_set_features(struct virtio_user_dev *dev)
>
> pthread_mutex_lock(&dev->mutex);
>
> - if (dev->backend_type == VIRTIO_USER_BACKEND_VHOST_USER &&
> - dev->vhostfd < 0)
> - goto error;
> -
> /* Step 0: tell vhost to create queues */
> if (virtio_user_queue_setup(dev, virtio_user_create_queue) < 0)
> goto error;
> @@ -190,11 +186,6 @@ virtio_user_start_device(struct virtio_user_dev *dev)
> rte_mcfg_mem_read_lock();
> pthread_mutex_lock(&dev->mutex);
>
> - /* Vhost-user client not connected yet, will start later */
> - if (dev->backend_type == VIRTIO_USER_BACKEND_VHOST_USER &&
> - dev->vhostfd < 0)
> - goto out;
> -
> /* Step 2: share memory regions */
> ret = dev->ops->set_memory_table(dev);
> if (ret < 0)
> @@ -213,7 +204,7 @@ virtio_user_start_device(struct virtio_user_dev *dev)
> goto error;
>
> dev->started = true;
> -out:
> +
> pthread_mutex_unlock(&dev->mutex);
> rte_mcfg_mem_read_unlock();
>
> @@ -421,36 +412,36 @@ virtio_user_dev_setup(struct virtio_user_dev *dev)
> PMD_DRV_LOG(ERR, "Server mode only supports
> vhost-user!");
> return -1;
> }
> + }
> +
> + if (dev->backend_type == VIRTIO_USER_BACKEND_VHOST_USER) {
> dev->ops = &virtio_ops_user;
> - } else {
> - if (dev->backend_type == VIRTIO_USER_BACKEND_VHOST_USER) {
> - dev->ops = &virtio_ops_user;
> - } else if (dev->backend_type ==
> - VIRTIO_USER_BACKEND_VHOST_KERNEL) {
> - dev->ops = &virtio_ops_kernel;
> -
> - dev->vhostfds = malloc(dev->max_queue_pairs *
> - sizeof(int));
> - dev->tapfds = malloc(dev->max_queue_pairs *
> - sizeof(int));
> - if (!dev->vhostfds || !dev->tapfds) {
> - PMD_INIT_LOG(ERR, "(%s) Failed to allocate
> FDs", dev-
> >path);
> - return -1;
If tapfds failed on malloc, this will lead to vhostfds not freed?
And, should we free the fds when errors happen later in this function?
Thanks!
Chenbo
> - }
> -
> - for (q = 0; q < dev->max_queue_pairs; ++q) {
> - dev->vhostfds[q] = -1;
> - dev->tapfds[q] = -1;
> - }
> - } else if (dev->backend_type ==
> - VIRTIO_USER_BACKEND_VHOST_VDPA) {
> - dev->ops = &virtio_ops_vdpa;
> - } else {
> - PMD_DRV_LOG(ERR, "(%s) Unknown backend type",
> dev->path);
