Re: [dpdk-dev] [PATCH v3 13/21] vhost: add helpers for packed virtqueues

[Maxime Coquelin]

On 04/05/2018 12:10 PM, Jens Freimann wrote:

Add some helper functions to set/check descriptor flags
and toggle the used wrap counter.

Signed-off-by: Jens Freimann <jfreim...@redhat.com>
---
  lib/librte_vhost/virtio-1.1.h | 44 +++++++++++++++++++++++++++++++++++++++++++
  1 file changed, 44 insertions(+)

diff --git a/lib/librte_vhost/virtio-1.1.h b/lib/librte_vhost/virtio-1.1.h
index 7b48caed7..e77d7aa6c 100644
--- a/lib/librte_vhost/virtio-1.1.h
+++ b/lib/librte_vhost/virtio-1.1.h

Shouldn't the file be named virtio-packed.h?

@@ -15,4 +15,48 @@ struct vring_desc_packed {
        uint16_t flags;
  };

+static inline void

+toggle_wrap_counter(struct vhost_virtqueue *vq)
+{
+       vq->used_wrap_counter ^= 1;
+}
+
+static inline int
+desc_is_avail(struct vhost_virtqueue *vq, struct vring_desc_packed *desc)
+{
+       if (vq->used_wrap_counter == 1) {
+               if ((desc->flags & VRING_DESC_F_AVAIL) &&
+                               !(desc->flags & VRING_DESC_F_USED))
+                       return 1;
+       }
+       if (vq->used_wrap_counter == 0) {
+               if (!(desc->flags & VRING_DESC_F_AVAIL) &&
+                               (desc->flags & VRING_DESC_F_USED))
+                       return 1;
+       }
+       return 0;
+}
+
+static inline void
+_set_desc_used(struct vring_desc_packed *desc, int wrap_counter)
+{
+       uint16_t flags = desc->flags;
+
+       if (wrap_counter == 1) {
+               flags |= VRING_DESC_F_USED;
+               flags |= VRING_DESC_F_AVAIL;
+       } else {
+               flags &= ~VRING_DESC_F_USED;
+               flags &= ~VRING_DESC_F_AVAIL;
+       }
+
+       desc->flags = flags;
+}
+
+static inline void
+set_desc_used(struct vhost_virtqueue *vq, struct vring_desc_packed *desc)
+{
+       _set_desc_used(desc, vq->used_wrap_counter);
+}
+

Maybe prefix all with vring_

  #endif /* __VIRTIO_PACKED_H */