[dpdk-dev] [PATCH 04/17] net/virtio: add packed virtqueue helpers

[Jens Freimann]

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

Signed-off-by: Jens Freimann <jfreim...@redhat.com>
---
 drivers/net/virtio/virtio_ring.h | 33 +++++++++++++++++++++++++++++++++
 drivers/net/virtio/virtqueue.c   |  3 +++
 2 files changed, 36 insertions(+)

diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h
index 6eb0077..2de2ede 100644
--- a/drivers/net/virtio/virtio_ring.h
+++ b/drivers/net/virtio/virtio_ring.h
@@ -74,12 +74,45 @@ struct vring_desc_packed {
 
 struct vring {
        unsigned int num;
+       unsigned int avail_wrap_counter;
        struct vring_desc  *desc;
        struct vring_avail *avail;
        struct vring_used  *used;
        struct vring_desc_packed *desc_packed;
 };
 
+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 |= DESC_AVAIL;
+               flags &= ~DESC_USED;
+       } else {
+               flags &= ~DESC_AVAIL;
+               flags |= DESC_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 & DESC_AVAIL) == !(desc->flags & DESC_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 a7d0a9c..6806056 100644
--- a/drivers/net/virtio/virtqueue.c
+++ b/drivers/net/virtio/virtqueue.c
@@ -65,6 +65,9 @@ struct rte_mbuf *
        uint16_t used_idx, desc_idx;
        uint16_t nb_used, i;
 
+       if (vtpci_packed_queue(vq->hw))
+               return;
+
        nb_used = VIRTQUEUE_NUSED(vq);
 
        for (i = 0; i < nb_used; i++) {
-- 
1.8.3.1