[Qemu-devel] [PATCH v2 3/4] virtio-9p: factor out virtio_9p_error_err()

[Greg Kurz]

When an unrecoverable is hit, we need to set the broken flag of the virtio
device, detach the queue element and free it. This is currently open coded
in handle_9p_output(). It is fine since this is the only function that can
set the broken flag. But if we want to be able to do this from other places,
we must consolidate the logic in a helper.

Signed-off-by: Greg Kurz <address@hidden>
--
v2: - rely on the existing virtio_error() API
---
 hw/9pfs/virtio-9p-device.c |   35 ++++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
index 3782f437029b..c71659823fdc 100644
--- a/hw/9pfs/virtio-9p-device.c
+++ b/hw/9pfs/virtio-9p-device.c
@@ -22,21 +22,32 @@
 
 static const struct V9fsTransport virtio_9p_transport;
 
+static void virtio_9p_free_element(V9fsVirtioState *v, unsigned int idx)
+{
+    VirtQueueElement **pelem = &v->elems[idx];
+    g_free(*pelem);
+    *pelem = NULL;
+}
+
 static void virtio_9p_push_and_notify(V9fsPDU *pdu)
 {
     V9fsState *s = pdu->s;
     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
-    VirtQueueElement *elem = v->elems[pdu->idx];
 
     /* push onto queue and notify */
-    virtqueue_push(v->vq, elem, pdu->size);
-    g_free(elem);
-    v->elems[pdu->idx] = NULL;
+    virtqueue_push(v->vq, v->elems[pdu->idx], pdu->size);
+    virtio_9p_free_element(v, pdu->idx);
 
     /* FIXME: we should batch these completions */
     virtio_notify(VIRTIO_DEVICE(v), v->vq);
 }
 
+#define virtio_9p_error(v, idx, ...) {                 \
+    virtio_error(VIRTIO_DEVICE(v), ## __VA_ARGS__);    \
+    virtqueue_detach_element(v->vq, v->elems[idx], 0); \
+    virtio_9p_free_element(v, idx);                    \
+}
+
 static void handle_9p_output(VirtIODevice *vdev, VirtQueue *vq)
 {
     V9fsVirtioState *v = (V9fsVirtioState *)vdev;
@@ -52,22 +63,19 @@ static void handle_9p_output(VirtIODevice *vdev, VirtQueue 
*vq)
         if (!elem) {
             goto out_free_pdu;
         }
+        v->elems[pdu->idx] = elem;
 
         if (elem->in_num == 0) {
-            virtio_error(vdev,
-                         "The guest sent a VirtFS request without space for "
-                         "the reply");
-            goto out_free_req;
+            virtio_9p_error(v, pdu->idx, "The guest sent a VirtFS request 
without space for the reply");
+            goto out_free_pdu;
         }
         QEMU_BUILD_BUG_ON(sizeof(out) != 7);
 
-        v->elems[pdu->idx] = elem;
         len = iov_to_buf(elem->out_sg, elem->out_num, 0,
                          &out, sizeof(out));
         if (len != sizeof(out)) {
-            virtio_error(vdev, "The guest sent a malformed VirtFS request: "
-                         "header size is %zd, should be 7", len);
-            goto out_free_req;
+            virtio_9p_error(v, pdu->idx, "The guest sent a malformed VirtFS 
request: header size is %zd, should be 7", len);
+            goto out_free_pdu;
         }
 
         pdu->size = le32_to_cpu(out.size_le);
@@ -81,9 +89,6 @@ static void handle_9p_output(VirtIODevice *vdev, VirtQueue 
*vq)
 
     return;
 
-out_free_req:
-    virtqueue_detach_element(vq, elem, 0);
-    g_free(elem);
 out_free_pdu:
     pdu_free(pdu);
 }