On Mon, Nov 14, 2016 at 12:35:48PM -0800, Kees Cook wrote:
> On Mon, Nov 14, 2016 at 9:39 AM, Peter Zijlstra <[email protected]> wrote:
> > Because home-rolling your own is _awesome_, stop doing it. Provide
> > kref_put_lock(), just like kref_put_mutex() but for a spinlock.
> >
> > Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> > ---
> > include/linux/kref.h | 21 +++++++++++++++------
> > net/sunrpc/svcauth.c | 15 ++++++++++-----
> > 2 files changed, 25 insertions(+), 11 deletions(-)
> >
> > --- a/include/linux/kref.h
> > +++ b/include/linux/kref.h
> > @@ -86,12 +86,21 @@ static inline int kref_put_mutex(struct
> > struct mutex *lock)
> > {
> > WARN_ON(release == NULL);
>
> This WARN_ON makes sense, yes, though it seems like it should be deal
> with differently. If it's NULL, we'll just Oops when we call release()
> later... Seems like this should saturate the kref or something else
> similar.
So I simply took the pattern from the existing kref_put().
But I like it more in these kref_put_{lock,mutex}() variants, because
someone will need to unlock. If we simply crash/bug without unlock we'll
have broken state the rest of the kernel cannot fix up.
