[dpdk-dev] [PATCH v3 04/21] net/virtio: add packed virtqueue helpers

Maxime Coquelin maxime.coquelin at redhat.com
Thu Apr 5 16:27:51 CEST 2018


On 04/05/2018 12:10 PM, Jens Freimann wrote:
> Add helper functions to set/clear and check descriptor flags.
> 
> Signed-off-by: Jens Freimann <jfreimann at redhat.com>
> ---
>   drivers/net/virtio/virtio_ring.h | 33 +++++++++++++++++++++++++++++++++
>   drivers/net/virtio/virtqueue.c   | 10 ++++++++++
>   2 files changed, 43 insertions(+)
> 
> diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h
> index 54a11d2a9..663b4b01d 100644
> --- a/drivers/net/virtio/virtio_ring.h
> +++ b/drivers/net/virtio/virtio_ring.h
> @@ -78,6 +78,7 @@ struct vring_packed_desc_event {
>   
>   struct vring {
>   	unsigned int num;
> +	unsigned int avail_wrap_counter;
>   	union {
>   		struct vring_desc_packed *desc_packed;
>   		struct vring_desc *desc;
> @@ -92,6 +93,38 @@ struct vring {
>   	};
>   };
>   
> +static inline void toggle_wrap_counter(struct vring *vr)
Please follow the coding style of the driver:

static inline void
toggle_wrap_counter(struct vring *vr)

I would also prefix the functions with vring_ to keep consistency.
> +{
> +	vr->avail_wrap_counter ^= 1;
> +}
> +
> +static inline void _set_desc_avail(struct vring_desc_packed *desc,
> +				   int wrap_counter)
> +{
> +	uint16_t flags = desc->flags;
> +
> +	if (wrap_counter) {
> +		flags |= VRING_DESC_F_AVAIL;
> +		flags &= ~VRING_DESC_F_USED;
> +	} else {
> +		flags &= ~VRING_DESC_F_AVAIL;
> +		flags |= VRING_DESC_F_USED;
> +	}
> +
> +	desc->flags = flags;
> +}
> +
> +static inline void set_desc_avail(struct vring *vr,
> +				  struct vring_desc_packed *desc)
> +{
> +	_set_desc_avail(desc, vr->avail_wrap_counter);
> +}
> +
> +static inline int desc_is_used(struct vring_desc_packed *desc)
> +{
> +	return !(desc->flags & VRING_DESC_F_AVAIL) == !(desc->flags & VRING_DESC_F_USED);
> +}
> +
>   /* The standard layout for the ring is a continuous chunk of memory which
>    * looks like this.  We assume num is a power of 2.
>    *
> diff --git a/drivers/net/virtio/virtqueue.c b/drivers/net/virtio/virtqueue.c
> index a7d0a9cbe..4f95ed5c8 100644
> --- a/drivers/net/virtio/virtqueue.c
> +++ b/drivers/net/virtio/virtqueue.c
> @@ -58,6 +58,7 @@ virtqueue_detach_unused(struct virtqueue *vq)
>   void
>   virtqueue_rxvq_flush(struct virtqueue *vq)
>   {
> +	struct vring_desc_packed *descs = vq->vq_ring.desc_packed;
>   	struct virtnet_rx *rxq = &vq->rxq;
>   	struct virtio_hw *hw = vq->hw;
>   	struct vring_used_elem *uep;
> @@ -65,6 +66,15 @@ virtqueue_rxvq_flush(struct virtqueue *vq)
>   	uint16_t used_idx, desc_idx;
>   	uint16_t nb_used, i;
>   
> +	if (vtpci_packed_queue(vq->hw)) {
> +		i = vq->vq_used_cons_idx & (vq->vq_nentries - 1);
> +		while (desc_is_used(&descs[i])) {
> +			rte_pktmbuf_free(vq->sw_ring[i]);
> +			vq->vq_free_cnt++;
> +		}
> +		return;
> +	}
> +
>   	nb_used = VIRTQUEUE_NUSED(vq);
>   
>   	for (i = 0; i < nb_used; i++) {
> 

With style comments taken into account:

Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>



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