virtio_pci: document why we defer kfree

The reason we defer kfree until release function is because it's a general rule for kobjects: kfree of the reference counter itself is only legal in the release function. Previous patch didn't make this clear, document this in code. Cc: [email protected] Signed-off-by: Michael S. Tsirkin <[email protected]>
kyagi · Jan 6, 2015 · a1eb03f · a1eb03f
1 parent 63bd62a
commit a1eb03f
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
@@ -216,6 +216,9 @@ static void virtio_pci_release_dev(struct device *_d)
 	struct virtio_device *vdev = dev_to_virtio(_d);
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 
+	/* As struct device is a kobject, it's not safe to
+	 * free the memory (including the reference counter itself)
+	 * until it's release callback. */
 	kfree(vp_dev);
 }