On 2020/3/18 下午8:22, Jason Gunthorpe wrote:

On Wed, Mar 18, 2020 at 04:03:27PM +0800, Jason Wang wrote:

quoted

From: Zhu Lingshan <redacted>
+
+static int ifcvf_vdpa_attach(struct ifcvf_adapter *adapter)
+{
+	int ret;
+
+	adapter->vdpa_dev  = vdpa_alloc_device(adapter->dev, adapter->dev,
+					       &ifc_vdpa_ops);
+	if (IS_ERR(adapter->vdpa_dev)) {
+		IFCVF_ERR(adapter->dev, "Failed to init ifcvf on vdpa bus");
+		put_device(&adapter->vdpa_dev->dev);
+		return -ENODEV;
+	}

The point of having an alloc call is so that the drivers
ifcvf_adaptor memory could be placed in the same struct - eg use
container_of to flip between them, and have a kref for both memories.

It seem really weird to have an alloc followed immediately by
register.

I admit the ifcvf_adapter is not correctly ref-counted. What you suggest 
should work. But it looks to me the following is more cleaner since the 
members of ifcvf_adapter are all related to PCI device not vDPA itself.

- keep the current layout of ifcvf_adapter
- merge vdpa_alloc_device() and vdpa_register_device()
- use devres to bind ifcvf_adapter refcnt/lifcycle to the under PCI device

If we go for the container_of method, we probably need

- accept a size of parent parent structure in vdpa_alloc_device() and 
mandate vdpa_device to be the first member of ifcvf_adapter
- we need provide a way to free resources of parent structure when we 
destroy vDPA device

What's your thought?

quoted

diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
index c30eb55030be..de64b88ee7e4 100644
+++ b/drivers/virtio/virtio_vdpa.c

@@ -362,6 +362,7 @@ static int virtio_vdpa_probe(struct vdpa_device *vdpa)
  		goto err;
  
  	vdpa_set_drvdata(vdpa, vd_dev);
+	dev_info(vd_dev->vdev.dev.parent, "device attached to VDPA bus\n");
  
  	return 0;

This hunk seems out of place

Jason

Right, will fix.

Thanks