Add helper functions to set/clear and check descriptor flags.
Signed-off-by: Jens Freimann <jfreim...@redhat.com>
---
drivers/net/virtio/virtio_ring.h | 38 ++++++++++++++++++++++++++++++++++++++
drivers/net/virtio/virtqueue.h | 19 +++++++++++++++++++
2 files changed, 57 insertions(+)
diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h
index 76168eed7..4eed023cc 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 +93,43 @@ 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.h b/drivers/net/virtio/virtqueue.h
index cc2e7c0f6..081b27a52 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)
+ toggle_wrap_counter(&vq->vq_ring);
+ vq->vq_avail_idx = idx;
+
+ return vq->vq_avail_idx;
+}
+
static inline void
vring_desc_init_packed(struct vring *vr, int n)
{
--
2.14.3
