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

[Jens Freimann <jfreimann@redhat.com>]

Add helper functions to set/clear and check descriptor flags.

Signed-off-by: Jens Freimann <jfreimann@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)
+{
+	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++) {
-- 
2.14.3