Re: [dpdk-dev] [PATCH v2] net/virtio: support to turn on/off traffic flow

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 04/19/2017 08:29 AM, Zhiyong Yang wrote:
> Current virtio_dev_stop only disables interrupt and marks link down,
> When it is invoked, tx/rx traffic flows still work. This is a strange
> behavior. The patch supports the switch of flow.
> 
> Signed-off-by: Zhiyong Yang <zhiyong.yang@intel.com>
> ---
> 
> Changes in V2:
> Use the flag "started" introduced by yuanhan's applied patch, rx/tx
> check the per-device defined var "started".
> 
>   drivers/net/virtio/virtio_rxtx.c             | 21 ++++++++++++++-------
>   drivers/net/virtio/virtio_rxtx_simple.c      |  5 +++++
>   drivers/net/virtio/virtio_rxtx_simple_neon.c |  6 +++++-
>   drivers/net/virtio/virtio_rxtx_simple_sse.c  |  6 +++++-
>   4 files changed, 29 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> index ea0bd9d..fbc96df 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -725,7 +725,7 @@ virtio_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
>   {
>   	struct virtnet_rx *rxvq = rx_queue;
>   	struct virtqueue *vq = rxvq->vq;
> -	struct virtio_hw *hw;
> +	struct virtio_hw *hw = vq->hw;
>   	struct rte_mbuf *rxm, *new_mbuf;
>   	uint16_t nb_used, num, nb_rx;
>   	uint32_t len[VIRTIO_MBUF_BURST_SZ];
> @@ -736,6 +736,10 @@ virtio_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
>   	int offload;
>   	struct virtio_net_hdr *hdr;
>   
> +	nb_rx = 0;

Only cosmetics, but I would do like in Tx path, i.e. set nb_rx to 0
directly at declaration time.

> +	if (unlikely(hw->started == 0))
> +		return nb_rx;
> +
>   	nb_used = VIRTQUEUE_NUSED(vq);
>   
>   	virtio_rmb();
> @@ -748,8 +752,6 @@ virtio_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
>   	num = virtqueue_dequeue_burst_rx(vq, rcv_pkts, len, num);
>   	PMD_RX_LOG(DEBUG, "used:%d dequeue:%d", nb_used, num);
>   
> -	hw = vq->hw;
> -	nb_rx = 0;
>   	nb_enqueued = 0;
>   	hdr_size = hw->vtnet_hdr_size;
>   	offload = rx_offload_enabled(hw);
> @@ -834,7 +836,7 @@ virtio_recv_mergeable_pkts(void *rx_queue,
>   {
>   	struct virtnet_rx *rxvq = rx_queue;
>   	struct virtqueue *vq = rxvq->vq;
> -	struct virtio_hw *hw;
> +	struct virtio_hw *hw = vq->hw;
>   	struct rte_mbuf *rxm, *new_mbuf;
>   	uint16_t nb_used, num, nb_rx;
>   	uint32_t len[VIRTIO_MBUF_BURST_SZ];
> @@ -848,14 +850,16 @@ virtio_recv_mergeable_pkts(void *rx_queue,
>   	uint32_t hdr_size;
>   	int offload;
>   
> +	nb_rx = 0;
Ditto.

> +	if (unlikely(hw->started == 0))
> +		return nb_rx;
> +
>   	nb_used = VIRTQUEUE_NUSED(vq);
>   
>   	virtio_rmb();
>   
>   	PMD_RX_LOG(DEBUG, "used:%d", nb_used);
>   
> -	hw = vq->hw;
> -	nb_rx = 0;
>   	i = 0;
>   	nb_enqueued = 0;
>   	seg_num = 0;
> @@ -1005,9 +1009,12 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
>   	struct virtqueue *vq = txvq->vq;
>   	struct virtio_hw *hw = vq->hw;
>   	uint16_t hdr_size = hw->vtnet_hdr_size;
> -	uint16_t nb_used, nb_tx;
> +	uint16_t nb_used, nb_tx = 0;
>   	int error;
>   
> +	if (unlikely(hw->started == 0))
> +		return nb_tx;
> +
>   	if (unlikely(nb_pkts < 1))
>   		return nb_pkts;
>   
> diff --git a/drivers/net/virtio/virtio_rxtx_simple.c b/drivers/net/virtio/virtio_rxtx_simple.c
> index b651e53..542cf80 100644
> --- a/drivers/net/virtio/virtio_rxtx_simple.c
> +++ b/drivers/net/virtio/virtio_rxtx_simple.c
> @@ -89,12 +89,17 @@ virtio_xmit_pkts_simple(void *tx_queue, struct rte_mbuf **tx_pkts,
>   {
>   	struct virtnet_tx *txvq = tx_queue;
>   	struct virtqueue *vq = txvq->vq;
> +	struct virtio_hw *hw = vq->hw;
>   	uint16_t nb_used;
>   	uint16_t desc_idx;
>   	struct vring_desc *start_dp;
>   	uint16_t nb_tail, nb_commit;
>   	int i;
>   	uint16_t desc_idx_max = (vq->vq_nentries >> 1) - 1;
> +	uint16_t nb_tx = 0;
> +
> +	if (unlikely(hw->started == 0))
> +		return nb_tx;
Maybe just return 0 directly, nb_tx really needed here?

>   
>   	nb_used = VIRTQUEUE_NUSED(vq);
>   	rte_compiler_barrier();
> diff --git a/drivers/net/virtio/virtio_rxtx_simple_neon.c b/drivers/net/virtio/virtio_rxtx_simple_neon.c
> index 793eefb..ecc62ad 100644
> --- a/drivers/net/virtio/virtio_rxtx_simple_neon.c
> +++ b/drivers/net/virtio/virtio_rxtx_simple_neon.c
> @@ -72,12 +72,13 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
>   {
>   	struct virtnet_rx *rxvq = rx_queue;
>   	struct virtqueue *vq = rxvq->vq;
> +	struct virtio_hw *hw = vq->hw;
>   	uint16_t nb_used;
>   	uint16_t desc_idx;
>   	struct vring_used_elem *rused;
>   	struct rte_mbuf **sw_ring;
>   	struct rte_mbuf **sw_ring_end;
> -	uint16_t nb_pkts_received;
> +	uint16_t nb_pkts_received = 0;
>   
>   	uint8x16_t shuf_msk1 = {
>   		0xFF, 0xFF, 0xFF, 0xFF, /* packet type */
> @@ -106,6 +107,9 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
>   		0, 0
>   	};
>   
> +	if (unlikely(hw->started == 0))
> +		return nb_pkts_received;
Ditto.

> +
>   	if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
>   		return 0;
>   
> diff --git a/drivers/net/virtio/virtio_rxtx_simple_sse.c b/drivers/net/virtio/virtio_rxtx_simple_sse.c
> index 87bb5c6..7cf0f8b 100644
> --- a/drivers/net/virtio/virtio_rxtx_simple_sse.c
> +++ b/drivers/net/virtio/virtio_rxtx_simple_sse.c
> @@ -74,12 +74,13 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
>   {
>   	struct virtnet_rx *rxvq = rx_queue;
>   	struct virtqueue *vq = rxvq->vq;
> +	struct virtio_hw *hw = vq->hw;
>   	uint16_t nb_used;
>   	uint16_t desc_idx;
>   	struct vring_used_elem *rused;
>   	struct rte_mbuf **sw_ring;
>   	struct rte_mbuf **sw_ring_end;
> -	uint16_t nb_pkts_received;
> +	uint16_t nb_pkts_received = 0;
>   	__m128i shuf_msk1, shuf_msk2, len_adjust;
>   
>   	shuf_msk1 = _mm_set_epi8(
> @@ -109,6 +110,9 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
>   		0, (uint16_t)-vq->hw->vtnet_hdr_size,
>   		0, 0);
>   
> +	if (unlikely(hw->started == 0))
> +		return nb_pkts_received;
Ditto.

> +
>   	if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
>   		return 0;


As said, only cosmetic comments, it looks otherwise valid to me.
If you fix these, feel free to add my:
Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime