vhost/net: virtio 1.0 byte swap

I had to add an explicit tag to suppress compiler warning:
gcc isn't smart enough to notice that
len is always initialized since function is called with size > 0.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index dce5c58..c218188 100644 (file)
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -416,7 +416,7 @@ static void handle_tx(struct vhost_net *net)
                        struct ubuf_info *ubuf;
                        ubuf = nvq->ubuf_info + nvq->upend_idx;
 
-                       vq->heads[nvq->upend_idx].id = head;
+                       vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head);
                        vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS;
                        ubuf->callback = vhost_zerocopy_callback;
                        ubuf->ctx = nvq->ubufs;
@@ -500,6 +500,10 @@ static int get_rx_bufs(struct vhost_virtqueue *vq,
        int headcount = 0;
        unsigned d;
        int r, nlogs = 0;
+       /* len is always initialized before use since we are always called with
+        * datalen > 0.
+        */
+       u32 uninitialized_var(len);
 
        while (datalen > 0 && headcount < quota) {
                if (unlikely(seg >= UIO_MAXIOV)) {
@@ -527,13 +531,14 @@ static int get_rx_bufs(struct vhost_virtqueue *vq,
                        nlogs += *log_num;
                        log += *log_num;
                }
-               heads[headcount].id = d;
-               heads[headcount].len = iov_length(vq->iov + seg, in);
-               datalen -= heads[headcount].len;
+               heads[headcount].id = cpu_to_vhost32(vq, d);
+               len = iov_length(vq->iov + seg, in);
+               heads[headcount].len = cpu_to_vhost32(vq, len);
+               datalen -= len;
                ++headcount;
                seg += in;
        }
-       heads[headcount - 1].len += datalen;
+       heads[headcount - 1].len = cpu_to_vhost32(vq, len - datalen);
        *iovcount = seg;
        if (unlikely(log))
                *log_num = nlogs;