vdpa_sim_net: complete the initialization before register the device

Initialization must be completed before calling _vdpa_register_device()
since it can connect the device to the vDPA bus, so requests can arrive
after that call.

So for example vdpasim_net_work(), which uses the net->*_stats variables,
can be scheduled before they are initialized.

Let's move _vdpa_register_device() to the end of vdpasim_net_dev_add()
and add a comment to avoid future issues.

Fixes: 0899774cb360 ("vdpa_sim_net: vendor satistics")
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20230329160321.187176-1-sgarzare@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
index 862f405..dfe2ce3 100644 (file)
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
@@ -466,16 +466,21 @@ static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 
        vdpasim_net_setup_config(simdev, config);
 
-       ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_NET_VQ_NUM);
-       if (ret)
-               goto reg_err;
-
        net = sim_to_net(simdev);
 
        u64_stats_init(&net->tx_stats.syncp);
        u64_stats_init(&net->rx_stats.syncp);
        u64_stats_init(&net->cq_stats.syncp);
 
+       /*
+        * Initialization must be completed before this call, since it can
+        * connect the device to the vDPA bus, so requests can arrive after
+        * this call.
+        */
+       ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_NET_VQ_NUM);
+       if (ret)
+               goto reg_err;
+
        return 0;
 
 reg_err: