As mentioned at drivers/base/core.c: /* * NOTE: _Never_ directly free @dev after calling this function, even * if it returned an error! Always use put_device() to give up the * reference initialized in this function instead. */ virtio_register_device may fail before/after call device_register, the caller should do a proper cleanup. Caller cann't use kfree directly, if virtio_register_device has already called device_register. Caller cann't use put_device directly, if virtio_register_device has not yet call device_register, because kobject_put may give a warning cause dev->kobj has not been initialized.
Signed-off-by: weiping zhang <[email protected]> --- drivers/virtio/virtio.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index c5b057bd..4f0718b 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -309,6 +309,19 @@ void unregister_virtio_driver(struct virtio_driver *driver) } EXPORT_SYMBOL_GPL(unregister_virtio_driver); +/** + * register_virtio_device - register virtio device + * + * @dev : virtio device interested + * + * This funciton may fail after call device_register, as mentioned at + * drivers/base/core.c we must use put_device(), _never_ directly free @dev. + * The caller should take care of the status of @dev and determine to use + * put_device or kfree. If @dev in VIRTIO_CONFIG_S_ACKNOWLEDGE status that + * means caller should use put_device otherwise use kfree directly. + * + * Returns: 0 on success, error on failure. + */ int register_virtio_device(struct virtio_device *dev) { int err; -- 2.9.4 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
