[PATCH] driver core: Clarify which counterparts to use to device_add()

From: Borislav Petkov
Date: Thu Apr 18 2019 - 13:42:07 EST

From: Borislav Petkov <bp@xxxxxxx>

It is not absolutely clear from the docs how the cleanup path after
device_add() should look like so spell it out explicitly.

No functional changes, just documentation.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
drivers/base/core.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 4aeaa0c92bda..fd7511e04e62 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1999,6 +1999,11 @@ static int device_private_init(struct device *dev)
* 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.
+ *
+ * Rule of thumb is: if device_add() succeeds, you should call
+ * device_del() when you want to get rid of it. If device_add() has
+ * *not* succeeded, use *only* put_device() to drop the reference
+ * count.
int device_add(struct device *dev)