docs: kref: Clarify the use of two kref_put() in example code

Eventhough the current documentation explains that the reference count
gets incremented by both kref_init() and kref_get(), it is often
misunderstood that only one instance of kref_put() is needed in the
example code. So let's clarify that a bit.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Manivannan Sadhasivam 2020-02-13 18:23:11 +05:30 committed by Jonathan Corbet
parent 021622df55
commit ef45e78fdc

View File

@ -128,6 +128,10 @@ since we already have a valid pointer that we own a refcount for. The
put needs no lock because nothing tries to get the data without
already holding a pointer.
In the above example, kref_put() will be called 2 times in both success
and error paths. This is necessary because the reference count got
incremented 2 times by kref_init() and kref_get().
Note that the "before" in rule 1 is very important. You should never
do something like::