[PATCH v8 34/50] vhost/net: virtio 1.0 byte swap

Michael S. Tsirkin
2014-12-01T16:05:34Z

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>
---
drivers/vhost/net.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index dce5c58..c218188 100644
--- 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;
--
MST