Re: [dpdk-dev] [PATCH v3 44/44] net/virtio: handle Virtio-user setup failure properly

["Xia, Chenbo" <chenbo.xia@intel.com>]

Hi Maxime,

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Tuesday, January 26, 2021 1:15 AM
> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>; olivier.matz@6wind.com;
> amorenoz@redhat.com; david.marchand@redhat.com
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH v3 44/44] net/virtio: handle Virtio-user setup failure
> properly
> 
> This patch fixes virtio_user_dev_setup() error path,
> by cleaning all resources it allocates. It introduces
> virtio_user_dev_uninit_notify() that cleans all open
> FDs. It implies assigning all FDs to -1 at init time.
> 
> With these changes done, virtio_user_dev_init_notify()
> can be simplified.
> 
> Suggested-by: Adrian Moreno <amorenoz@redhat.com>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  .../net/virtio/virtio_user/virtio_user_dev.c  | 68 +++++++++++++------
>  1 file changed, 47 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> index a1e32158bb..7c60022a26 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> @@ -283,13 +283,7 @@ virtio_user_dev_init_notify(struct virtio_user_dev *dev)
>  	int callfd;
>  	int kickfd;
> 
> -	for (i = 0; i < VIRTIO_MAX_VIRTQUEUES; ++i) {
> -		if (i >= dev->max_queue_pairs * 2) {
> -			dev->kickfds[i] = -1;
> -			dev->callfds[i] = -1;
> -			continue;
> -		}
> -
> +	for (i = 0; i < dev->max_queue_pairs * 2; i++) {
>  		/* May use invalid flag, but some backend uses kickfd and
>  		 * callfd as criteria to judge if dev is alive. so finally we
>  		 * use real event_fd.
> @@ -297,25 +291,48 @@ virtio_user_dev_init_notify(struct virtio_user_dev *dev)
>  		callfd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
>  		if (callfd < 0) {
>  			PMD_DRV_LOG(ERR, "(%s) callfd error, %s", dev->path,
> strerror(errno));
> -			break;
> +			goto err;
>  		}
>  		kickfd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
>  		if (kickfd < 0) {
>  			close(callfd);
>  			PMD_DRV_LOG(ERR, "(%s) kickfd error, %s", dev->path,
> strerror(errno));
> -			break;
> +			goto err;
>  		}
>  		dev->callfds[i] = callfd;
>  		dev->kickfds[i] = kickfd;
>  	}
> 
> -	if (i < VIRTIO_MAX_VIRTQUEUES) {
> -		for (j = 0; j < i; ++j) {
> -			close(dev->callfds[j]);
> +	return 0;
> +err:
> +	for (j = 0; j < i; j++) {
> +		if (dev->kickfds[j] >= 0) {
>  			close(dev->kickfds[j]);
> +			dev->kickfds[j] = -1;
>  		}
> +		if (dev->callfds[j] >= 0) {
> +			close(dev->callfds[j]);
> +			dev->callfds[j] = -1;
> +		}
> +	}
> 
> -		return -1;
> +	return -1;
> +}
> +
> +static int

Use void?

> +virtio_user_dev_uninit_notify(struct virtio_user_dev *dev)
> +{
> +	uint32_t i;
> +
> +	for (i = 0; i < VIRTIO_MAX_VIRTQUEUES; ++i) {

Do we need to loop for VIRTIO_MAX_VIRTQUEUES? Kick/call fds would only be set
valid in virtio_user_dev_init_notify, and since virtio_user_dev_init_notify only
loop for dev->max_queue_pairs * 2, this function will also loop for dev->max_queue_pairs * 2?
Other fds should be -1, right?

Thanks,
Chenbo

> +		if (dev->kickfds[i] >= 0) {
> +			close(dev->kickfds[i]);
> +			dev->kickfds[i] = -1;
> +		}
> +		if (dev->callfds[i] >= 0) {
> +			close(dev->callfds[i]);
> +			dev->callfds[i] = -1;
> +		}
>  	}
> 
>  	return 0;
> @@ -427,15 +444,22 @@ virtio_user_dev_setup(struct virtio_user_dev *dev)
> 
>  	if (virtio_user_dev_init_notify(dev) < 0) {
>  		PMD_INIT_LOG(ERR, "(%s) Failed to init notifiers\n", dev->path);
> -		return -1;
> +		goto destroy;
>  	}
> 
>  	if (virtio_user_fill_intr_handle(dev) < 0) {
>  		PMD_INIT_LOG(ERR, "(%s) Failed to init interrupt handler\n", dev-
> >path);
> -		return -1;
> +		goto uninit;
>  	}
> 
>  	return 0;
> +
> +uninit:
> +	virtio_user_dev_uninit_notify(dev);
> +destroy:
> +	dev->ops->destroy(dev);
> +
> +	return -1;
>  }
> 
>  /* Use below macro to filter features from vhost backend */
> @@ -466,9 +490,16 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char
> *path, int queues,
>  		     enum virtio_user_backend_type backend_type)
>  {
>  	uint64_t backend_features;
> +	int i;
> 
>  	pthread_mutex_init(&dev->mutex, NULL);
>  	strlcpy(dev->path, path, PATH_MAX);
> +
> +	for (i = 0; i < VIRTIO_MAX_VIRTQUEUES; i++) {
> +		dev->kickfds[i] = -1;
> +		dev->callfds[i] = -1;
> +	}
> +
>  	dev->started = 0;
>  	dev->max_queue_pairs = queues;
>  	dev->queue_pairs = 1; /* mq disabled by default */
> @@ -565,16 +596,11 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char
> *path, int queues,
>  void
>  virtio_user_dev_uninit(struct virtio_user_dev *dev)
>  {
> -	uint32_t i;
> -
>  	virtio_user_stop_device(dev);
> 
>  	rte_mem_event_callback_unregister(VIRTIO_USER_MEM_EVENT_CLB_NAME, dev);
> 
> -	for (i = 0; i < dev->max_queue_pairs * 2; ++i) {
> -		close(dev->callfds[i]);
> -		close(dev->kickfds[i]);
> -	}
> +	virtio_user_dev_uninit_notify(dev);
> 
>  	free(dev->ifname);
> 
> --
> 2.29.2