tree 7b2b3299b6ef785790336042ab28c0bffa37debb
parent 6f0c0580b70c89094b3422ba81118c7b959c7556
author Dmitry Torokhov <dmitry.torokhov@gmail.com> 1350867439 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1350885037 +0300

char_dev: pin parent kobject

In certain cases (for example when a cdev structure is embedded into
another object whose lifetime is controlled by a separate kobject) it is
beneficial to tie lifetime of another object to the lifetime of
character device so that related object is not freed until after
char_dev object is freed.

To achieve this let's pin kobject's parent when doing cdev_add() and
unpin when last reference to cdev structure is being released.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>