[PATCH v6 09/12] vdpa: Extract vhost_vdpa_net_cvq_add from vhost_vdpa_net_handle_ctrl_avail

["Eugenio Pérez" <eperezma@redhat.com>]

So we can reuse it to inject state messages.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
--
v6:
* Do not assume in buffer sent to the device is sizeof(virtio_net_ctrl_ack)

v5:
* Do not use an artificial !NULL VirtQueueElement
* Use only out size instead of iovec dev_buffers for these functions.
---
 net/vhost-vdpa.c | 59 +++++++++++++++++++++++++++++++-----------------
 1 file changed, 38 insertions(+), 21 deletions(-)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 2c6a26cca0..a3ca6af69f 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -331,6 +331,38 @@ static void vhost_vdpa_net_cvq_stop(NetClientState *nc)
     }
 }
 
+static ssize_t vhost_vdpa_net_cvq_add(VhostVDPAState *s, size_t out_len,
+                                      size_t in_len)
+{
+    /* Buffers for the device */
+    const struct iovec out = {
+        .iov_base = s->cvq_cmd_out_buffer,
+        .iov_len = out_len,
+    };
+    const struct iovec in = {
+        .iov_base = s->cvq_cmd_in_buffer,
+        .iov_len = sizeof(virtio_net_ctrl_ack),
+    };
+    VhostShadowVirtqueue *svq = g_ptr_array_index(s->vhost_vdpa.shadow_vqs, 0);
+    int r;
+
+    r = vhost_svq_add(svq, &out, 1, &in, 1, NULL);
+    if (unlikely(r != 0)) {
+        if (unlikely(r == -ENOSPC)) {
+            qemu_log_mask(LOG_GUEST_ERROR, "%s: No space on device queue\n",
+                          __func__);
+        }
+        return r;
+    }
+
+    /*
+     * We can poll here since we've had BQL from the time we sent the
+     * descriptor. Also, we need to take the answer before SVQ pulls by itself,
+     * when BQL is released
+     */
+    return vhost_svq_poll(svq);
+}
+
 static NetClientInfo net_vhost_vdpa_cvq_info = {
     .type = NET_CLIENT_DRIVER_VHOST_VDPA,
     .size = sizeof(VhostVDPAState),
@@ -387,23 +419,18 @@ static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,
                                             void *opaque)
 {
     VhostVDPAState *s = opaque;
-    size_t in_len, dev_written;
+    size_t in_len;
     virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
     /* Out buffer sent to both the vdpa device and the device model */
     struct iovec out = {
         .iov_base = s->cvq_cmd_out_buffer,
     };
-    /* In buffer sent to the device */
-    const struct iovec dev_in = {
-        .iov_base = s->cvq_cmd_in_buffer,
-        .iov_len = sizeof(virtio_net_ctrl_ack),
-    };
     /* in buffer used for device model */
     const struct iovec in = {
         .iov_base = &status,
         .iov_len = sizeof(status),
     };
-    int r = -EINVAL;
+    ssize_t dev_written = -EINVAL;
     bool ok;
 
     out.iov_len = iov_to_buf(elem->out_sg, elem->out_num, 0,
@@ -414,21 +441,11 @@ static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,
         goto out;
     }
 
-    r = vhost_svq_add(svq, &out, 1, &dev_in, 1, elem);
-    if (unlikely(r != 0)) {
-        if (unlikely(r == -ENOSPC)) {
-            qemu_log_mask(LOG_GUEST_ERROR, "%s: No space on device queue\n",
-                          __func__);
-        }
+    dev_written = vhost_vdpa_net_cvq_add(s, out.iov_len, sizeof(status));
+    if (unlikely(dev_written < 0)) {
         goto out;
     }
 
-    /*
-     * We can poll here since we've had BQL from the time we sent the
-     * descriptor. Also, we need to take the answer before SVQ pulls by itself,
-     * when BQL is released
-     */
-    dev_written = vhost_svq_poll(svq);
     if (unlikely(dev_written < sizeof(status))) {
         error_report("Insufficient written data (%zu)", dev_written);
         goto out;
@@ -436,7 +453,7 @@ static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,
 
     memcpy(&status, s->cvq_cmd_in_buffer, sizeof(status));
     if (status != VIRTIO_NET_OK) {
-        goto out;
+        return VIRTIO_NET_ERR;
     }
 
     status = VIRTIO_NET_ERR;
@@ -453,7 +470,7 @@ out:
     }
     vhost_svq_push_elem(svq, elem, MIN(in_len, sizeof(status)));
     g_free(elem);
-    return r;
+    return MAX(dev_written, 0);
 }
 
 static const VhostShadowVirtqueueOps vhost_vdpa_net_svq_ops = {
-- 
2.31.1