[dpdk-dev] [PATCH v5 03/11] net/virtio: add packed virtqueue helpers

[Jens Freimann]

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 | 26 ++++++++++++++++++++++++++
 drivers/net/virtio/virtqueue.h   | 19 +++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h
index e2c597434..f3b23f419 100644
--- a/drivers/net/virtio/virtio_ring.h
+++ b/drivers/net/virtio/virtio_ring.h
@@ -78,6 +78,8 @@ struct vring_packed_desc_event {
 
 struct vring {
 	unsigned int num;
+	unsigned int avail_wrap_counter;
+	unsigned int used_wrap_counter;
 	union {
 		struct vring_desc_packed *desc_packed;
 		struct vring_desc *desc;
@@ -92,6 +94,30 @@ struct vring {
 	};
 };
 
+static inline void
+_set_desc_avail(struct vring_desc_packed *desc, int wrap_counter)
+{
+	desc->flags |= VRING_DESC_F_AVAIL(wrap_counter) |
+		       VRING_DESC_F_USED(!wrap_counter);
+}
+
+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, struct vring *vr)
+{
+	uint16_t used, avail;
+
+	used = !!(desc->flags & VRING_DESC_F_USED(1));
+	avail = !!(desc->flags & VRING_DESC_F_AVAIL(1));
+
+	return used == avail && used == vr->used_wrap_counter;
+}
+
 /* 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.h b/drivers/net/virtio/virtqueue.h
index d2a0b651a..53fce61b4 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -245,6 +245,25 @@ struct virtio_tx_region {
 			   __attribute__((__aligned__(16)));
 };
 
+static inline uint16_t
+increment_pq_index(uint16_t idx, size_t ring_size)
+{
+	return ++idx >= ring_size ? 0 : idx;
+}
+
+static inline uint16_t
+update_pq_avail_index(struct virtqueue *vq)
+{
+	uint16_t idx;
+
+	idx = increment_pq_index(vq->vq_avail_idx, vq->vq_nentries);
+	if (idx == 0)
+		vq->vq_ring.avail_wrap_counter ^= 1;
+	vq->vq_avail_idx = idx;
+
+	return vq->vq_avail_idx;
+}
+
 static inline void
 vring_desc_init_packed(struct vring *vr, int n)
 {
-- 
2.17.1