virtio-pci-modern: factor out modern device initialization logic

This patch factors out the modern device initialization logic into a
helper. Note that it still depends on the caller to enable pci device
which allows the caller to use e.g devres.
Signed-off-by: NJason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210104065503.199631-4-jasowang@redhat.comSigned-off-by: NMichael S. Tsirkin <mst@redhat.com>

drivers/virtio/virtio_pci_modern.c

@@ -703,11 +703,16 @@ static inline void check_offsets(void)
 		     offsetof(struct virtio_pci_common_cfg, queue_used_hi));
 }
 
-/* the PCI probing function */
-int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
+/*
+ * vp_modern_probe: probe the modern virtio pci device, note that the
+ * caller is required to enable PCI device before calling this function.
+ * @mdev: the modern virtio-pci device
+ *
+ * Return 0 on succeed otherwise fail
+ */
+static int vp_modern_probe(struct virtio_pci_modern_device *mdev)
 {
-	struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
-	struct pci_dev *pci_dev = vp_dev->pci_dev;
+	struct pci_dev *pci_dev = mdev->pci_dev;
 	int err, common, isr, notify, device;
 	u32 notify_length;
 	u32 notify_offset;
@@ -826,18 +831,8 @@ int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
 					      &mdev->device_len);
 		if (!mdev->device)
 			goto err_map_device;
-
-		vp_dev->vdev.config = &virtio_pci_config_ops;
-	} else {
-		vp_dev->vdev.config = &virtio_pci_config_nodev_ops;
 	}
 
-	vp_dev->config_vector = vp_config_vector;
-	vp_dev->setup_vq = setup_vq;
-	vp_dev->del_vq = del_vq;
-	vp_dev->isr = mdev->isr;
-	vp_dev->vdev.id = mdev->id;
-
 	return 0;
 
 err_map_device:
@@ -851,6 +846,33 @@ int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
 	return err;
 }
 
+/* the PCI probing function */
+int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
+{
+	struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
+	struct pci_dev *pci_dev = vp_dev->pci_dev;
+	int err;
+
+	mdev->pci_dev = pci_dev;
+
+	err = vp_modern_probe(mdev);
+	if (err)
+		return err;
+
+	if (mdev->device)
+		vp_dev->vdev.config = &virtio_pci_config_ops;
+	else
+		vp_dev->vdev.config = &virtio_pci_config_nodev_ops;
+
+	vp_dev->config_vector = vp_config_vector;
+	vp_dev->setup_vq = setup_vq;
+	vp_dev->del_vq = del_vq;
+	vp_dev->isr = mdev->isr;
+	vp_dev->vdev.id = mdev->id;
+
+	return 0;
+}
+
 void virtio_pci_modern_remove(struct virtio_pci_device *vp_dev)
 {
 	struct virtio_pci_modern_device *mdev = &vp_dev->mdev;