Re: [PATCH] vdpa: fix gcc cvq_isolated uninitialized variable warning

[Philippe Mathieu-Daudé]

On 11/9/23 23:54, Stefan Hajnoczi wrote:
> gcc 13.2.1 emits the following warning:
>
>    net/vhost-vdpa.c: In function ‘net_vhost_vdpa_init.constprop’:
>    net/vhost-vdpa.c:1394:25: error: ‘cvq_isolated’ may be used uninitialized 
> [-Werror=maybe-uninitialized]
>     1394 |         s->cvq_isolated = cvq_isolated;
>          |         ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
>    net/vhost-vdpa.c:1355:9: note: ‘cvq_isolated’ was declared here
>     1355 |     int cvq_isolated;
>          |         ^~~~~~~~~~~~
>    cc1: all warnings being treated as errors
>
> Cc: Eugenio Pérez <eperezma@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>   net/vhost-vdpa.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index 34202ca009..7eaee841aa 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -1352,7 +1352,7 @@ static NetClientState *net_vhost_vdpa_init(NetClientState 
> *peer,
>       VhostVDPAState *s;
>       int ret = 0;
>       assert(name);
> -    int cvq_isolated;
> +    int cvq_isolated = 0;
>   
>       if (is_datapath) {
>           nc = qemu_new_net_client(&net_vhost_vdpa_info, peer, device,

Alternatively:

-- >8 --
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 34202ca009..218fe0c305 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -1352,13 +1352,12 @@ static NetClientState 
*net_vhost_vdpa_init(NetClientState *peer,
     VhostVDPAState *s;
     int ret = 0;
     assert(name);
-    int cvq_isolated;

     if (is_datapath) {
         nc = qemu_new_net_client(&net_vhost_vdpa_info, peer, device,
                                  name);
     } else {
-        cvq_isolated = vhost_vdpa_probe_cvq_isolation(vdpa_device_fd, 
features,
+        int cvq_isolated = 
vhost_vdpa_probe_cvq_isolation(vdpa_device_fd, features,
                                                       queue_pair_index 
* 2,
                                                       errp);
         if (unlikely(cvq_isolated < 0)) {
@@ -1391,7 +1390,7 @@ static NetClientState 
*net_vhost_vdpa_init(NetClientState *peer,

         s->vhost_vdpa.shadow_vq_ops = &vhost_vdpa_net_svq_ops;
         s->vhost_vdpa.shadow_vq_ops_opaque = s;
-        s->cvq_isolated = cvq_isolated;
+        s->cvq_isolated = true;

---

Whichever you prefer:

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>