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 <zhangweiping@xxxxxxxxxxxxxxx>
---
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
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