Re: [PATCH 4/7] vhost-user-blk: Add Error parameter to vhost_user_blk_start()

[Raphael Norwitz <raphael.norwitz@nutanix.com>]

On Wed, Jun 09, 2021 at 05:46:55PM +0200, Kevin Wolf wrote:
> Instead of letting the caller make up a meaningless error message, add
> an Error parameter to allow reporting the real error.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>

> ---
>  hw/block/vhost-user-blk.c | 31 +++++++++++++++----------------
>  1 file changed, 15 insertions(+), 16 deletions(-)
> 
> diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
> index 0cb56baefb..e9382e152a 100644
> --- a/hw/block/vhost-user-blk.c
> +++ b/hw/block/vhost-user-blk.c
> @@ -113,7 +113,7 @@ const VhostDevConfigOps blk_ops = {
>      .vhost_dev_config_notifier = vhost_user_blk_handle_config_change,
>  };
>  
> -static int vhost_user_blk_start(VirtIODevice *vdev)
> +static int vhost_user_blk_start(VirtIODevice *vdev, Error **errp)
>  {
>      VHostUserBlk *s = VHOST_USER_BLK(vdev);
>      BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> @@ -121,19 +121,19 @@ static int vhost_user_blk_start(VirtIODevice *vdev)
>      int i, ret;
>  
>      if (!k->set_guest_notifiers) {
> -        error_report("binding does not support guest notifiers");
> +        error_setg(errp, "binding does not support guest notifiers");
>          return -ENOSYS;
>      }
>  
>      ret = vhost_dev_enable_notifiers(&s->dev, vdev);
>      if (ret < 0) {
> -        error_report("Error enabling host notifiers: %d", -ret);
> +        error_setg_errno(errp, -ret, "Error enabling host notifiers");
>          return ret;
>      }
>  
>      ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, true);
>      if (ret < 0) {
> -        error_report("Error binding guest notifier: %d", -ret);
> +        error_setg_errno(errp, -ret, "Error binding guest notifier");
>          goto err_host_notifiers;
>      }
>  
> @@ -141,27 +141,27 @@ static int vhost_user_blk_start(VirtIODevice *vdev)
>  
>      ret = vhost_dev_prepare_inflight(&s->dev, vdev);
>      if (ret < 0) {
> -        error_report("Error set inflight format: %d", -ret);
> +        error_setg_errno(errp, -ret, "Error setting inflight format");
>          goto err_guest_notifiers;
>      }
>  
>      if (!s->inflight->addr) {
>          ret = vhost_dev_get_inflight(&s->dev, s->queue_size, s->inflight);
>          if (ret < 0) {
> -            error_report("Error get inflight: %d", -ret);
> +            error_setg_errno(errp, -ret, "Error getting inflight");
>              goto err_guest_notifiers;
>          }
>      }
>  
>      ret = vhost_dev_set_inflight(&s->dev, s->inflight);
>      if (ret < 0) {
> -        error_report("Error set inflight: %d", -ret);
> +        error_setg_errno(errp, -ret, "Error setting inflight");
>          goto err_guest_notifiers;
>      }
>  
>      ret = vhost_dev_start(&s->dev, vdev);
>      if (ret < 0) {
> -        error_report("Error starting vhost: %d", -ret);
> +        error_setg_errno(errp, -ret, "Error starting vhost");
>          goto err_guest_notifiers;
>      }
>      s->started_vu = true;
> @@ -214,6 +214,7 @@ static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
>  {
>      VHostUserBlk *s = VHOST_USER_BLK(vdev);
>      bool should_start = virtio_device_started(vdev, status);
> +    Error *local_err = NULL;
>      int ret;
>  
>      if (!vdev->vm_running) {
> @@ -229,10 +230,9 @@ static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
>      }
>  
>      if (should_start) {
> -        ret = vhost_user_blk_start(vdev);
> +        ret = vhost_user_blk_start(vdev, &local_err);
>          if (ret < 0) {
> -            error_report("vhost-user-blk: vhost start failed: %s",
> -                         strerror(-ret));
> +            error_reportf_err(local_err, "vhost-user-blk: vhost start failed: ");
>              qemu_chr_fe_disconnect(&s->chardev);
>          }
>      } else {
> @@ -270,6 +270,7 @@ static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev,
>  static void vhost_user_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
>  {
>      VHostUserBlk *s = VHOST_USER_BLK(vdev);
> +    Error *local_err = NULL;
>      int i, ret;
>  
>      if (!vdev->start_on_kick) {
> @@ -287,10 +288,9 @@ static void vhost_user_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
>      /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
>       * vhost here instead of waiting for .set_status().
>       */
> -    ret = vhost_user_blk_start(vdev);
> +    ret = vhost_user_blk_start(vdev, &local_err);
>      if (ret < 0) {
> -        error_report("vhost-user-blk: vhost start failed: %s",
> -                     strerror(-ret));
> +        error_reportf_err(local_err, "vhost-user-blk: vhost start failed: ");
>          qemu_chr_fe_disconnect(&s->chardev);
>          return;
>      }
> @@ -340,9 +340,8 @@ static int vhost_user_blk_connect(DeviceState *dev, Error **errp)
>  
>      /* restore vhost state */
>      if (virtio_device_started(vdev, vdev->status)) {
> -        ret = vhost_user_blk_start(vdev);
> +        ret = vhost_user_blk_start(vdev, errp);
>          if (ret < 0) {
> -            error_setg_errno(errp, -ret, "vhost start failed");
>              return ret;
>          }
>      }
> -- 
> 2.30.2
>