From c578662ec973f2cdc5e7a81f9fec1bfb45440342 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Sun, 4 Jan 2015 17:28:27 +0200 Subject: [PATCH] virtio_pci: document why we defer kfree commit a1eb03f546d651a8f39c7d0692b1f7f5b4e7e3cd upstream. 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. Signed-off-by: Michael S. Tsirkin [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings --- drivers/virtio/virtio_pci.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index 65c907dc354e..13f6cd8fffd2 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -615,6 +615,9 @@ 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); } -- 2.30.2