The fmc-chardev module was over-locking, by calling misc
register/unregister while holding its spinlock. This reported a
"scheduling while atomic" error.
Since the misc driver already serializes operations internally, this
commit downgrades the fmc-chardev lock to just cover its own list.
Reported-by: Sasha Levin <email@example.com>
Reported-by: Fengguang Wu <firstname.lastname@example.org>
Signed-off-by: Alessandro Rubini <email@example.com>
Signed-off-by: Greg Kroah-Hartman <firstname.lastname@example.org>