[dpdk-dev] [PATCH v2 2/3] vhost: rework async feature struct

[Jiayu Hu <jiayu.hu@intel.com>]

No need to use bitfields in the structure rte_vhost_async_features.
This patch reworks the structure to improve code readability. In
addition, add preserved padding fields on the structure for future
usage.

Signed-off-by: Jiayu Hu <jiayu.hu@intel.com>
---
 examples/vhost/main.c       |  4 ++--
 lib/vhost/rte_vhost_async.h | 24 ++++++++----------------
 lib/vhost/vhost.c           | 13 +++++--------
 3 files changed, 15 insertions(+), 26 deletions(-)

diff --git a/examples/vhost/main.c b/examples/vhost/main.c
index d2179ea..ec1a5b4 100644
--- a/examples/vhost/main.c
+++ b/examples/vhost/main.c
@@ -1468,7 +1468,7 @@ new_device(int vid)
 		vid, vdev->coreid);
 
 	if (async_vhost_driver) {
-		struct rte_vhost_async_features f;
+		struct rte_vhost_async_features f = {0};
 		struct rte_vhost_async_channel_ops channel_ops;
 
 		if (dma_type != NULL && strncmp(dma_type, "ioat", 4) == 0) {
@@ -1480,7 +1480,7 @@ new_device(int vid)
 			f.async_threshold = 256;
 
 			return rte_vhost_async_channel_register(vid, VIRTIO_RXQ,
-				f.intval, &channel_ops);
+				f, &channel_ops);
 		}
 	}
 
diff --git a/lib/vhost/rte_vhost_async.h b/lib/vhost/rte_vhost_async.h
index 6faa31f..12c6962 100644
--- a/lib/vhost/rte_vhost_async.h
+++ b/lib/vhost/rte_vhost_async.h
@@ -93,18 +93,13 @@ struct async_inflight_info {
 };
 
 /**
- *  dma channel feature bit definition
+ *  dma channel features
  */
 struct rte_vhost_async_features {
-	union {
-		uint32_t intval;
-		struct {
-			uint32_t async_inorder:1;
-			uint32_t resvd_0:15;
-			uint32_t async_threshold:12;
-			uint32_t resvd_1:4;
-		};
-	};
+	uint32_t async_threshold;
+	uint32_t resvd_0[13];
+	uint8_t async_inorder;
+	uint8_t resvd_1[7];
 };
 
 /**
@@ -115,11 +110,7 @@ struct rte_vhost_async_features {
  * @param queue_id
  *  vhost queue id async channel to be attached to
  * @param features
- *  DMA channel feature bit
- *    b0       : DMA supports inorder data transfer
- *    b1  - b15: reserved
- *    b16 - b27: Packet length threshold for DMA transfer
- *    b28 - b31: reserved
+ *  DMA channel feature structure
  * @param ops
  *  DMA operation callbacks
  * @return
@@ -127,7 +118,8 @@ struct rte_vhost_async_features {
  */
 __rte_experimental
 int rte_vhost_async_channel_register(int vid, uint16_t queue_id,
-	uint32_t features, struct rte_vhost_async_channel_ops *ops);
+	struct rte_vhost_async_features features,
+	struct rte_vhost_async_channel_ops *ops);
 
 /**
  * unregister a dma channel for vhost
diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index 53a470f..835aad8 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -1620,18 +1620,15 @@ int rte_vhost_extern_callback_register(int vid,
 }
 
 int rte_vhost_async_channel_register(int vid, uint16_t queue_id,
-					uint32_t features,
-					struct rte_vhost_async_channel_ops *ops)
+		struct rte_vhost_async_features features,
+		struct rte_vhost_async_channel_ops *ops)
 {
 	struct vhost_virtqueue *vq;
 	struct virtio_net *dev = get_device(vid);
-	struct rte_vhost_async_features f;
 
 	if (dev == NULL || ops == NULL)
 		return -1;
 
-	f.intval = features;
-
 	if (queue_id >= VHOST_MAX_VRING)
 		return -1;
 
@@ -1640,7 +1637,7 @@ int rte_vhost_async_channel_register(int vid, uint16_t queue_id,
 	if (unlikely(vq == NULL || !dev->async_copy))
 		return -1;
 
-	if (unlikely(!f.async_inorder)) {
+	if (unlikely(!features.async_inorder)) {
 		VHOST_LOG_CONFIG(ERR,
 			"async copy is not supported on non-inorder mode "
 			"(vid %d, qid: %d)\n", vid, queue_id);
@@ -1720,8 +1717,8 @@ int rte_vhost_async_channel_register(int vid, uint16_t queue_id,
 	vq->async_ops.check_completed_copies = ops->check_completed_copies;
 	vq->async_ops.transfer_data = ops->transfer_data;
 
-	vq->async_inorder = f.async_inorder;
-	vq->async_threshold = f.async_threshold;
+	vq->async_inorder = features.async_inorder;
+	vq->async_threshold = features.async_threshold;
 
 	vq->async_registered = true;
 
-- 
2.7.4