Re: [PATCH] virtio: make PCI devices take a virtio_pci module ref

Anthony Liguori
2008-12-09T16:57:16Z

Mark McLoughlin wrote:
> On Mon, 2008-12-08 at 08:46 -0600, Anthony Liguori wrote:
>
> It feels a bit like busy work to generalise this since only virtio_pci
> can be built as a module, but here's a patch.
>
> The mkinitrd hack turns into:
>
> # Handle finding virtio bus implementations
> if [ -L ./virtio_module ] ; then
> findmodule $(basename $(readlink ./virtio_module))
> else if echo $PWD | grep -q /virtio-pci/ ; then
> findmodule virtio_pci
> fi; fi
>
> Cheers,
> Mark.
>
> [PATCH] virtio: add a 'virtio_module' sysfs symlink
>
> Add a way for userspace to determine which virtio bus transport a
> given device is associated with.
>
> This will be used by Fedora mkinitrd to generically determine e.g.
> that virtio_pci is needed to mount a given root filesystem.
>
> Signed-off-by: Mark McLoughlin <markmc@redhat.com>
>

Acked-by: Anthony Liguori <aliguori@us.ibm.com>

> ---
> drivers/virtio/virtio.c | 21 ++++++++++++++++++++-
> drivers/virtio/virtio_pci.c | 1 +
> include/linux/virtio_config.h | 2 ++
> 3 files changed, 23 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
> index 018c070..640ede8 100644
> --- a/drivers/virtio/virtio.c
> +++ b/drivers/virtio/virtio.c
> @@ -189,13 +189,32 @@ int register_virtio_device(struct virtio_device *dev)
> * matching driver. */
> err = device_register(&dev->dev);
> if (err)
> - add_status(dev, VIRTIO_CONFIG_S_FAILED);
> + goto out;
> +
> + /* Create a virtio_module symlink */
> + if (dev->config->owner) {
> + struct module_kobject *mk = &dev->config->owner->mkobj;
> +
> + err = sysfs_create_link(&dev->dev.kobj, &mk->kobj,
> + "virtio_module");
> + if (err)
> + goto unreg;
> + }
> +
> + return 0;
> +
> +unreg:
> + device_unregister(&dev->dev);
> +out:
> + add_status(dev, VIRTIO_CONFIG_S_FAILED);
> return err;
> }
> EXPORT_SYMBOL_GPL(register_virtio_device);
>
> void unregister_virtio_device(struct virtio_device *dev)
> {
> + if (dev->config->owner)
> + sysfs_remove_link(&dev->dev.kobj, "virtio_module");
> device_unregister(&dev->dev);
> }
> EXPORT_SYMBOL_GPL(unregister_virtio_device);
> diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
> index 939e0b4..59e928d 100644
> --- a/drivers/virtio/virtio_pci.c
> +++ b/drivers/virtio/virtio_pci.c
> @@ -328,6 +328,7 @@ static void vp_del_vq(struct virtqueue *vq)
> }
>
> static struct virtio_config_ops virtio_pci_config_ops = {
> + .owner = THIS_MODULE,
> .get = vp_get,
> .set = vp_set,
> .get_status = vp_get_status,
> diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> index bf8ec28..0a01cda 100644
> --- a/include/linux/virtio_config.h
> +++ b/include/linux/virtio_config.h
> @@ -33,6 +33,7 @@
>
> /**
> * virtio_config_ops - operations for configuring a virtio device
> + * @owner: the module implementing these ops, usually THIS_MODULE
> * @get: read the value of a configuration field
> * vdev: the virtio_device
> * offset: the offset of the configuration field
> @@ -68,6 +69,7 @@
> */
> struct virtio_config_ops
> {
> + struct module *owner;
> void (*get)(struct virtio_device *vdev, unsigned offset,
> void *buf, unsigned len);
> void (*set)(struct virtio_device *vdev, unsigned offset,
>