vhost: remove notion of async descriptor

Now that IO vectors iterator have been simplified, the
rte_vhost_async_desc struct only contains a pointer on
the iterator array stored in the async metadata.

This patch removes it, and pass directly the iterators
array pointer to the transfer_data callback. Doing that,
we avoid declaring the descriptor array in the stack, and
also avoid the cost of filling it.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Jiayu Hu <jiayu.hu@intel.com>

diff --git a/examples/vhost/ioat.c b/examples/vhost/ioat.c
index a8c588d..9aeeb12 100644 (file)
--- a/examples/vhost/ioat.c
+++ b/examples/vhost/ioat.c
@@ -124,10 +124,10 @@ out:
 
 int32_t
 ioat_transfer_data_cb(int vid, uint16_t queue_id,
-               struct rte_vhost_async_desc *descs,
+               struct rte_vhost_iov_iter *iov_iter,
                struct rte_vhost_async_status *opaque_data, uint16_t count)
 {
-       uint32_t i_desc;
+       uint32_t i_iter;
        uint16_t dev_id = dma_bind[vid].dmas[queue_id * 2 + VIRTIO_RXQ].dev_id;
        struct rte_vhost_iov_iter *iter = NULL;
        unsigned long i_seg;
@@ -135,8 +135,8 @@ ioat_transfer_data_cb(int vid, uint16_t queue_id,
        unsigned short write = cb_tracker[dev_id].next_write;
 
        if (!opaque_data) {
-               for (i_desc = 0; i_desc < count; i_desc++) {
-                       iter = descs[i_desc].iter;
+               for (i_iter = 0; i_iter < count; i_iter++) {
+                       iter = iov_iter + i_iter;
                        i_seg = 0;
                        if (cb_tracker[dev_id].ioat_space < iter->nr_segs)
                                break;
@@ -161,7 +161,7 @@ ioat_transfer_data_cb(int vid, uint16_t queue_id,
        /* ring the doorbell */
        rte_ioat_perform_ops(dev_id);
        cb_tracker[dev_id].next_write = write;
-       return i_desc;
+       return i_iter;
 }
 
 int32_t

diff --git a/examples/vhost/ioat.h b/examples/vhost/ioat.h
index 62e163c..d9bf717 100644 (file)
--- a/examples/vhost/ioat.h
+++ b/examples/vhost/ioat.h
@@ -29,7 +29,7 @@ int open_ioat(const char *value);
 
 int32_t
 ioat_transfer_data_cb(int vid, uint16_t queue_id,
-               struct rte_vhost_async_desc *descs,
+               struct rte_vhost_iov_iter *iov_iter,
                struct rte_vhost_async_status *opaque_data, uint16_t count);
 
 int32_t
@@ -44,7 +44,7 @@ static int open_ioat(const char *value __rte_unused)
 
 static int32_t
 ioat_transfer_data_cb(int vid __rte_unused, uint16_t queue_id __rte_unused,
-               struct rte_vhost_async_desc *descs __rte_unused,
+               struct rte_vhost_iov_iter *iov_iter __rte_unused,
                struct rte_vhost_async_status *opaque_data __rte_unused,
                uint16_t count __rte_unused)
 {

diff --git a/lib/vhost/rte_vhost_async.h b/lib/vhost/rte_vhost_async.h
index 4ea5cfa..a87ea6b 100644 (file)
--- a/lib/vhost/rte_vhost_async.h
+++ b/lib/vhost/rte_vhost_async.h
@@ -26,14 +26,6 @@ struct rte_vhost_iov_iter {
        unsigned long nr_segs;
 };
 
-/**
- * dma transfer descriptor
- */
-struct rte_vhost_async_desc {
-       /* memory iov_iter */
-       struct rte_vhost_iov_iter *iter;
-};
-
 /**
  * dma transfer status
  */
@@ -55,17 +47,17 @@ struct rte_vhost_async_channel_ops {
         *  id of vhost device to perform data copies
         * @param queue_id
         *  queue id to perform data copies
-        * @param descs
-        *  an array of DMA transfer memory descriptors
+        * @param iov_iter
+        *  an array of IOV iterators
         * @param opaque_data
         *  opaque data pair sending to DMA engine
         * @param count
         *  number of elements in the "descs" array
         * @return
-        *  number of descs processed, negative value means error
+        *  number of IOV iterators processed, negative value means error
         */
        int32_t (*transfer_data)(int vid, uint16_t queue_id,
-               struct rte_vhost_async_desc *descs,
+               struct rte_vhost_iov_iter *iov_iter,
                struct rte_vhost_async_status *opaque_data,
                uint16_t count);
        /**

diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
index a2044aa..dfe864b 100644 (file)
--- a/lib/vhost/virtio_net.c
+++ b/lib/vhost/virtio_net.c
@@ -995,15 +995,6 @@ async_iter_reset(struct vhost_async *async)
        async->iovec_idx = 0;
 }
 
-static __rte_always_inline void
-async_fill_descs(struct vhost_async *async, struct rte_vhost_async_desc *descs)
-{
-       int i;
-
-       for (i = 0; i < async->iter_idx; i++)
-               descs[i].iter = async->iov_iter + i;
-}
-
 static __rte_always_inline int
 async_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
                        struct rte_mbuf *m, struct buf_vector *buf_vec,
@@ -1550,7 +1541,6 @@ virtio_dev_rx_async_submit_split(struct virtio_net *dev,
        uint16_t avail_head;
 
        struct vhost_async *async = vq->async;
-       struct rte_vhost_async_desc async_descs[MAX_PKT_BURST];
        struct async_inflight_info *pkts_info = async->pkts_info;
        uint32_t pkt_err = 0;
        int32_t n_xfer;
@@ -1595,9 +1585,7 @@ virtio_dev_rx_async_submit_split(struct virtio_net *dev,
        if (unlikely(pkt_idx == 0))
                return 0;
 
-       async_fill_descs(async, async_descs);
-
-       n_xfer = async->ops.transfer_data(dev->vid, queue_id, async_descs, 0, pkt_idx);
+       n_xfer = async->ops.transfer_data(dev->vid, queue_id, async->iov_iter, 0, pkt_idx);
        if (unlikely(n_xfer < 0)) {
                VHOST_LOG_DATA(ERR, "(%d) %s: failed to transfer data for queue id %d.\n",
                                dev->vid, __func__, queue_id);
@@ -1812,7 +1800,6 @@ virtio_dev_rx_async_submit_packed(struct virtio_net *dev,
        uint16_t num_descs;
 
        struct vhost_async *async = vq->async;
-       struct rte_vhost_async_desc async_descs[MAX_PKT_BURST];
        struct async_inflight_info *pkts_info = async->pkts_info;
        uint32_t pkt_err = 0;
        uint16_t slot_idx = 0;
@@ -1840,9 +1827,7 @@ virtio_dev_rx_async_submit_packed(struct virtio_net *dev,
        if (unlikely(pkt_idx == 0))
                return 0;
 
-       async_fill_descs(async, async_descs);
-
-       n_xfer = async->ops.transfer_data(dev->vid, queue_id, async_descs, 0, pkt_idx);
+       n_xfer = async->ops.transfer_data(dev->vid, queue_id, async->iov_iter, 0, pkt_idx);
        if (unlikely(n_xfer < 0)) {
                VHOST_LOG_DATA(ERR, "(%d) %s: failed to transfer data for queue id %d.\n",
                                dev->vid, __func__, queue_id);