[PATCH 07/10] vhost-vdpa: stick to -errno error return convention

[Roman Kagan <rvkagan@yandex-team.ru>]

Almost all VhostOps methods in vdpa_ops follow the convention of
returning negated errno on error.

Adjust the few that don't.  To that end, rework vhost_vdpa_add_status to
check if setting of the requested status bits has succeeded and return
the respective error code it hasn't, and propagate the error codes
wherever it's appropriate.

Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
---
 hw/virtio/vhost-vdpa.c | 37 +++++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 0d8051426c..a3b885902a 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -292,18 +292,34 @@ static int vhost_vdpa_call(struct vhost_dev *dev, unsigned long int request,
     return ret < 0 ? -errno : ret;
 }
 
-static void vhost_vdpa_add_status(struct vhost_dev *dev, uint8_t status)
+static int vhost_vdpa_add_status(struct vhost_dev *dev, uint8_t status)
 {
     uint8_t s;
+    int ret;
 
     trace_vhost_vdpa_add_status(dev, status);
-    if (vhost_vdpa_call(dev, VHOST_VDPA_GET_STATUS, &s)) {
-        return;
+    ret = vhost_vdpa_call(dev, VHOST_VDPA_GET_STATUS, &s);
+    if (ret < 0) {
+        return ret;
     }
 
     s |= status;
 
-    vhost_vdpa_call(dev, VHOST_VDPA_SET_STATUS, &s);
+    ret = vhost_vdpa_call(dev, VHOST_VDPA_SET_STATUS, &s);
+    if (ret < 0) {
+        return ret;
+    }
+
+    ret = vhost_vdpa_call(dev, VHOST_VDPA_GET_STATUS, &s);
+    if (ret < 0) {
+        return ret;
+    }
+
+    if (!(s & status)) {
+        return -EIO;
+    }
+
+    return 0;
 }
 
 static void vhost_vdpa_get_iova_range(struct vhost_vdpa *v)
@@ -484,7 +500,7 @@ static int vhost_vdpa_set_mem_table(struct vhost_dev *dev,
         }
     }
     if (mem->padding) {
-        return -1;
+        return -EINVAL;
     }
 
     return 0;
@@ -501,14 +517,11 @@ static int vhost_vdpa_set_features(struct vhost_dev *dev,
 
     trace_vhost_vdpa_set_features(dev, features);
     ret = vhost_vdpa_call(dev, VHOST_SET_FEATURES, &features);
-    uint8_t status = 0;
     if (ret) {
         return ret;
     }
-    vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
-    vhost_vdpa_call(dev, VHOST_VDPA_GET_STATUS, &status);
 
-    return !(status & VIRTIO_CONFIG_S_FEATURES_OK);
+    return vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
 }
 
 static int vhost_vdpa_set_backend_cap(struct vhost_dev *dev)
@@ -650,12 +663,8 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
     }
 
     if (started) {
-        uint8_t status = 0;
         memory_listener_register(&v->listener, &address_space_memory);
-        vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
-        vhost_vdpa_call(dev, VHOST_VDPA_GET_STATUS, &status);
-
-        return !(status & VIRTIO_CONFIG_S_DRIVER_OK);
+        return vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
     } else {
         vhost_vdpa_reset_device(dev);
         vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE |
-- 
2.33.1