Re: [dpdk-dev] [PATCH v3 1/2] vhost: vhost unix domain socket cleanup

[Thomas Monjalon <thomas.monjalon@6wind.com>]

Huawei,
I don't understand this reply. You forgot quoting, you didn't remove useless lines,
and you seem to reply to yourself.
Should this patch be applied?

2015-06-29 18:28, Xie, Huawei:
> On 6/19/2015 1:40 AM, Huawei Xie wrote:
> 
> rte_vhost_driver_unregister API will remove the listenfd for the specified path from event processing list, and then close it.
> 
> v2 changes:
> -minor code style fix: remove unnecessary new line
> 
> Signed-off-by: Huawei Xie <huawei.xie@intel.com><mailto:huawei.xie@intel.com>
> Signed-off-by: Peng Sun <peng.a.sun@intel.com><mailto:peng.a.sun@intel.com>
> ---
>  lib/librte_vhost/rte_virtio_net.h            |  3 ++
>  lib/librte_vhost/vhost_cuse/vhost-net-cdev.c |  9 ++++
>  lib/librte_vhost/vhost_user/vhost-net-user.c | 68 +++++++++++++++++++++++-----
>  lib/librte_vhost/vhost_user/vhost-net-user.h |  2 +-
>  4 files changed, 69 insertions(+), 13 deletions(-)
> 
> diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h
> index 5d38185..5630fbc 100644
> --- a/lib/librte_vhost/rte_virtio_net.h
> +++ b/lib/librte_vhost/rte_virtio_net.h
> @@ -188,6 +188,9 @@ int rte_vhost_enable_guest_notification(struct virtio_net *dev, uint16_t queue_i
>  /* Register vhost driver. dev_name could be different for multiple instance support. */
>  int rte_vhost_driver_register(const char *dev_name);
> 
> +/* Unregister vhost driver. This is only meaningful to vhost user. */
> +int rte_vhost_driver_unregister(const char *dev_name);
> +
>  /* Register callbacks. */
>  int rte_vhost_driver_callback_register(struct virtio_net_device_ops const * const);
>  /* Start vhost driver session blocking loop. */
> diff --git a/lib/librte_vhost/vhost_cuse/vhost-net-cdev.c b/lib/librte_vhost/vhost_cuse/vhost-net-cdev.c
> index 6b68abf..1ae7c49 100644
> --- a/lib/librte_vhost/vhost_cuse/vhost-net-cdev.c
> +++ b/lib/librte_vhost/vhost_cuse/vhost-net-cdev.c
> @@ -405,6 +405,15 @@ rte_vhost_driver_register(const char *dev_name)
>  }
> 
>  /**
> + * An empty function for unregister
> + */
> +int
> +rte_vhost_driver_unregister(const char *dev_name __rte_unused)
> +{
> +       return 0;
> +}
> +
> +/**
>   * The CUSE session is launched allowing the application to receive open,
>   * release and ioctl calls.
>   */
> diff --git a/lib/librte_vhost/vhost_user/vhost-net-user.c b/lib/librte_vhost/vhost_user/vhost-net-user.c
> index 31f1215..87a4711 100644
> --- a/lib/librte_vhost/vhost_user/vhost-net-user.c
> +++ b/lib/librte_vhost/vhost_user/vhost-net-user.c
> @@ -66,6 +66,8 @@ struct connfd_ctx {
>  struct _vhost_server {
>         struct vhost_server *server[MAX_VHOST_SERVER];
>         struct fdset fdset;
> +       int vserver_cnt;
> +       pthread_mutex_t server_mutex;
>  };
> 
>  static struct _vhost_server g_vhost_server = {
> @@ -74,10 +76,10 @@ static struct _vhost_server g_vhost_server = {
>                 .fd_mutex = PTHREAD_MUTEX_INITIALIZER,
>                 .num = 0
>         },
> +       .vserver_cnt = 0,
> +       .server_mutex = PTHREAD_MUTEX_INITIALIZER,
>  };
> 
> -static int vserver_idx;
> -
>  static const char *vhost_message_str[VHOST_USER_MAX] = {
>         [VHOST_USER_NONE] = "VHOST_USER_NONE",
>         [VHOST_USER_GET_FEATURES] = "VHOST_USER_GET_FEATURES",
> @@ -427,7 +429,6 @@ vserver_message_handler(int connfd, void *dat, int *remove)
>         }
>  }
> 
> -
>  /**
>   * Creates and initialise the vhost server.
>   */
> @@ -436,34 +437,77 @@ rte_vhost_driver_register(const char *path)
>  {
>         struct vhost_server *vserver;
> 
> -       if (vserver_idx == 0)
> +       pthread_mutex_lock(&g_vhost_server.server_mutex);
> +       if (ops == NULL)
>                 ops = get_virtio_net_callbacks();
> -       if (vserver_idx == MAX_VHOST_SERVER)
> +
> +       if (g_vhost_server.vserver_cnt == MAX_VHOST_SERVER) {
> +               RTE_LOG(ERR, VHOST_CONFIG,
> +                       "error: the number of servers reaches maximum\n");
> +               pthread_mutex_unlock(&g_vhost_server.server_mutex);
>                 return -1;
> +       }
> 
>         vserver = calloc(sizeof(struct vhost_server), 1);
> -       if (vserver == NULL)
> +       if (vserver == NULL) {
> +               pthread_mutex_unlock(&g_vhost_server.server_mutex);
>                 return -1;
> -
> -       unlink(path);
> +       }
> 
>         vserver->listenfd = uds_socket(path);
>         if (vserver->listenfd < 0) {
>                 free(vserver);
> +               pthread_mutex_unlock(&g_vhost_server.server_mutex);
>                 return -1;
>         }
> -       vserver->path = path;
> +
> +       vserver->path = strdup(path);
> 
>         fdset_add(&g_vhost_server.fdset, vserver->listenfd,
> -               vserver_new_vq_conn, NULL,
> -               vserver);
> +               vserver_new_vq_conn, NULL, vserver);
> 
> 
> In fd_man.c, in the event handler for connection fd,  the fd could be closed when receives no data.
> Before the following code snippet, as it isn't protected, there is chance we register the listenfd with the value of the just closed fd.
> so the following fdset_del could wrongly remove the new listenfd.
> would use fdset_del_slot to delete entry at fixed slot.
> 
>  if (remove1 || remove2)
>                                 fdset_del(pfdset, fd);
> 
> 
> another thing is when select is blocked, rte_vhost_driver_unregister/register  could remove/refill entries of some listenfd(s!!!).
> There is potential unwanted call on new listenfds, it is not a issue. would add comment to emphasize that.
> 
> 
> 
> 
> 
> 
> -       g_vhost_server.server[vserver_idx++] = vserver;
> +       g_vhost_server.server[g_vhost_server.vserver_cnt++] = vserver;
> +       pthread_mutex_unlock(&g_vhost_server.server_mutex);
> 
>         return 0;
>  }
> 
> 
> +/**
> + * Unregister the specified vhost server
> + */
> +int
> +rte_vhost_driver_unregister(const char *path)
> +{
> +       int i;
> +       int count;
> +
> +       pthread_mutex_lock(&g_vhost_server.server_mutex);
> +
> +       for (i = 0; i < g_vhost_server.vserver_cnt; i++) {
> +               if (!strcmp(g_vhost_server.server[i]->path, path)) {
> +                       fdset_del(&g_vhost_server.fdset,
> +                               g_vhost_server.server[i]->listenfd);
> +
> +                       close(g_vhost_server.server[i]->listenfd);
> +                       free(g_vhost_server.server[i]->path);
> +                       free(g_vhost_server.server[i]);
> +
> +                       unlink(path);
> +
> +                       count = --g_vhost_server.vserver_cnt;
> +                       g_vhost_server.server[i] = g_vhost_server.server[count];
> +                       g_vhost_server.server[count] = NULL;
> +                       pthread_mutex_unlock(&g_vhost_server.server_mutex);
> +
> +                       return 0;
> +               }
> +       }
> +       pthread_mutex_unlock(&g_vhost_server.server_mutex);
> +
> +       return -1;
> +}
> +
>  int
>  rte_vhost_driver_session_start(void)
>  {
> diff --git a/lib/librte_vhost/vhost_user/vhost-net-user.h b/lib/librte_vhost/vhost_user/vhost-net-user.h
> index 1b6be6c..2e72f3c 100644
> --- a/lib/librte_vhost/vhost_user/vhost-net-user.h
> +++ b/lib/librte_vhost/vhost_user/vhost-net-user.h
> @@ -41,7 +41,7 @@
>  #include "fd_man.h"
> 
>  struct vhost_server {
> -       const char *path; /**< The path the uds is bind to. */
> +       char *path; /**< The path the uds is bind to. */
>         int listenfd;     /**< The listener sockfd. */
>  };
> 
> 
>