ifcvf: ignore continuous setting same status value

User space may try to set status of same value multiple times,
this patch handles this case more efficiently by ignoring the
setting of the same status value.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Link: https://lore.kernel.org/r/1591352835-22441-3-git-send-email-lingshan.zhu@intel.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
index d529ed681fe646e9f6e9984b9c33bde28000e4bf..63a6366b43554b64fa5538b04afc59a6a1090ba0 100644 (file)
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
@@ -179,6 +179,9 @@ static void ifcvf_vdpa_set_status(struct vdpa_device *vdpa_dev, u8 status)
        adapter = dev_get_drvdata(vdpa_dev->dev.parent);
        status_old = ifcvf_get_status(vf);
 
+       if (status_old == status)
+               return;
+
        if ((status_old & VIRTIO_CONFIG_S_DRIVER_OK) &&
            !(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
                ifcvf_stop_datapath(adapter);