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Subject: Re: [PATCH RFC v8 02/11] vhost: use batched get_vq_desc version
To:     "Michael S. Tsirkin" <mst@redhat.com>, linux-kernel@vger.kernel.org
Cc:     kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
        netdev@vger.kernel.org, eperezma@redhat.com
References: <20200611113404.17810-1-mst@redhat.com>
 <20200611113404.17810-3-mst@redhat.com>
From:   Jason Wang <jasowang@redhat.com>
Message-ID: <0332b0cf-cf00-9216-042c-e870efa33626@redhat.com>
Date:   Wed, 17 Jun 2020 11:19:26 +0800
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On 2020/6/11 下午7:34, Michael S. Tsirkin wrote:
>   static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
>   {
>   	kfree(vq->descs);
> @@ -394,6 +400,9 @@ static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
>   	for (i = 0; i < dev->nvqs; ++i) {
>   		vq = dev->vqs[i];
>   		vq->max_descs = dev->iov_limit;
> +		if (vhost_vq_num_batch_descs(vq) < 0) {
> +			return -EINVAL;
> +		}


This check breaks vdpa which set iov_limit to zero. Consider iov_limit 
is meaningless to vDPA, I wonder we can skip the test when device 
doesn't use worker.

Thanks