Re: [dpdk-dev] [PATCH] vhost: fix return value

[Jens Freimann <jfreimann@redhat.com>]

On Wed, Jul 25, 2018 at 04:21:42PM +0800, Jiayu Hu wrote:
>This patch fixes the incorrect return value for rte_vhost_dequeue_burst()
>when virtqueue is not enabled or virtqueue address translation fails.
>
>Fixes: 62250c1d0978 ("vhost: extract split ring handling from Rx and Tx functions")

An alternative would be to add a new variable and not reuse the count
parameter as the return value, but your version is the minimal change
and fixes the bug, so

Reviewed-by: Jens Freimann <jfreiman@redhat.com> 

regards,
Jens 
>
>Signed-off-by: Jiayu Hu <jiayu.hu@intel.com>
>---
> lib/librte_vhost/virtio_net.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
>diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
>index 2b7ffcf..5d4b975 100644
>--- a/lib/librte_vhost/virtio_net.c
>+++ b/lib/librte_vhost/virtio_net.c
>@@ -1592,15 +1592,19 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
> 	if (unlikely(rte_spinlock_trylock(&vq->access_lock) == 0))
> 		return 0;
>
>-	if (unlikely(vq->enabled == 0))
>+	if (unlikely(vq->enabled == 0)) {
>+		count = 0;
> 		goto out_access_unlock;
>+	}
>
> 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> 		vhost_user_iotlb_rd_lock(vq);
>
> 	if (unlikely(vq->access_ok == 0))
>-		if (unlikely(vring_translate(dev, vq) < 0))
>+		if (unlikely(vring_translate(dev, vq) < 0)) {
>+			count = 0;
> 			goto out;
>+		}
>
> 	/*
> 	 * Construct a RARP broadcast packet, and inject it to the "pkts"
>-- 
>2.7.4
>