[Xen-devel] [PATCH 3/4] move virtqueue_unmap_sg calls from virtqueue_fill to virtqueue_push

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

Move the two virtqueue_unmap_sg calls from virtqueue_fill to
virtqueue_push: most virtio drivers simply call virtqueue_push so they
are unaffected. virtio-net calls virtqueue_fill directly, so we need to
make the two virtqueue_unmap_sg calls explicitely there.

Also replace the virtqueue_push call from virtio_net_handle_ctrl with an
open coded version it in place.

No functional changes.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
CC: jasowang@xxxxxxxxxx
CC: wency@xxxxxxxxxxxxxx
CC: mst@xxxxxxxxxx
CC: pbonzini@xxxxxxxxxx
---
 hw/net/virtio-net.c |    7 ++++++-
 hw/virtio/virtio.c  |    5 ++---
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 2ac6ce5..5035313 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -803,7 +803,10 @@ static void virtio_net_handle_ctrl(VirtIODevice *vdev, 
VirtQueue *vq)
         s = iov_from_buf(elem.in_sg, elem.in_num, 0, &status, sizeof(status));
         assert(s == sizeof(status));
 
-        virtqueue_push(vq, &elem, sizeof(status));
+        virtqueue_unmap_sg(elem.in_sg, elem.in_num, 1, sizeof(status));
+        virtqueue_unmap_sg(elem.out_sg, elem.out_num, 0, UINT_MAX);
+        virtqueue_fill(vq, &elem, sizeof(status), 0);
+        virtqueue_flush(vq, 1);
         virtio_notify(vdev, vq);
     }
 }
@@ -1052,6 +1055,8 @@ static ssize_t virtio_net_receive(NetClientState *nc, 
const uint8_t *buf, size_t
         }
 
         /* signal other side */
+        virtqueue_unmap_sg(elem.in_sg, elem.in_num, 1, total);
+        virtqueue_unmap_sg(elem.out_sg, elem.out_num, 0, UINT_MAX);
         virtqueue_fill(q->rx_vq, &elem, total, i++);
     }
 
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 4af31d0..0a6583a 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -240,9 +240,6 @@ void virtqueue_fill(VirtQueue *vq, const VirtQueueElement 
*elem,
 {
     trace_virtqueue_fill(vq, elem, len, idx);
 
-    virtqueue_unmap_sg(elem->in_sg, elem->in_num, 1, len);
-    virtqueue_unmap_sg(elem->out_sg, elem->out_num, 0, UINT_MAX);
-
     idx = (idx + vring_used_idx(vq)) % vq->vring.num;
 
     /* Get a pointer to the next entry in the used ring. */
@@ -267,6 +264,8 @@ void virtqueue_flush(VirtQueue *vq, unsigned int count)
 void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
                     unsigned int len)
 {
+    virtqueue_unmap_sg(elem->in_sg, elem->in_num, 1, len);
+    virtqueue_unmap_sg(elem->out_sg, elem->out_num, 0, UINT_MAX);
     virtqueue_fill(vq, elem, len, 0);
     virtqueue_flush(vq, 1);
 }
-- 
1.7.10.4


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