On 4/2/21 3:04 PM, Jiayu Hu wrote:
> Users can register async copy device in vring_state_changed(),
> when vhost queue is enabled. However, a deadlock occurs inside
> rte_vhost_async_channel_register(), if VHOST_USER_F_PROTOCOL_FEATURES
> is not supported, as vhost_user_msg_handler() takes vq->access_lock
> before calling vhost_user_set_vring_kick().
>
> This patch avoids async register deadlock by removing calling
> vring_state_changed() in vhost_user_set_vring_kick(). It's safe
> as vhost_user_msg_handler() will call vring_state_changed() anyway.
>
> Signed-off-by: Jiayu Hu <jiayu...@intel.com>
> ---
> lib/librte_vhost/vhost_user.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index 44c0452..8f0eba6 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -1918,9 +1918,6 @@ vhost_user_set_vring_kick(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
> */
> if (!(dev->features & (1ULL << VHOST_USER_F_PROTOCOL_FEATURES))) {
> vq->enabled = true;
> - if (dev->notify_ops->vring_state_changed)
> - dev->notify_ops->vring_state_changed(
> - dev->vid, file.index, 1);
> }
>
> if (vq->ready) {
>
As replied earlier on v1, I agree the call to vring_state_changed here
is not needed. But it might not be enough, there are other cases where
you could have issues.
Please add stable and Fixes tag.
Thanks,
Maxime
