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-rw-r--r--drivers/base/core.c17
1 files changed, 16 insertions, 1 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 4a67cc0c8b37..74dda4f697f9 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -632,6 +632,11 @@ static void klist_children_put(struct klist_node *n)
* may be used for reference counting of @dev after calling this
* function.
*
+ * All fields in @dev must be initialized by the caller to 0, except
+ * for those explicitly set to some other value. The simplest
+ * approach is to use kzalloc() to allocate the structure containing
+ * @dev.
+ *
* NOTE: Use put_device() to give up your reference instead of freeing
* @dev directly once you have called this function.
*/
@@ -930,6 +935,13 @@ int device_private_init(struct device *dev)
* to the global and sibling lists for the device, then
* adds it to the other relevant subsystems of the driver model.
*
+ * Do not call this routine or device_register() more than once for
+ * any device structure. The driver model core is not designed to work
+ * with devices that get unregistered and then spring back to life.
+ * (Among other things, it's very hard to guarantee that all references
+ * to the previous incarnation of @dev have been dropped.) Allocate
+ * and register a fresh new struct device instead.
+ *
* NOTE: _Never_ directly free @dev after calling this function, even
* if it returned an error! Always use put_device() to give up your
* reference instead.
@@ -1022,7 +1034,7 @@ int device_add(struct device *dev)
device_pm_add(dev);
/* Notify clients of device addition. This call must come
- * after dpm_sysf_add() and before kobject_uevent().
+ * after dpm_sysfs_add() and before kobject_uevent().
*/
if (dev->bus)
blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
@@ -1090,6 +1102,9 @@ name_error:
* have a clearly defined need to use and refcount the device
* before it is added to the hierarchy.
*
+ * For more information, see the kerneldoc for device_initialize()
+ * and device_add().
+ *
* 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.