Re: [PATCH 4/8] cgroup: export cgroup_get() and cgroup_put()

["Serge E. Hallyn" <serge.hallyn@ubuntu.com>]

On Tue, Nov 24, 2015 at 11:30:56AM -0500, Tejun Heo wrote:
> Hello,
> 
> On Mon, Nov 16, 2015 at 01:51:41PM -0600, serge@hallyn.com wrote:
> > From: Aditya Kali <adityakali@google.com>
> > 
> > move cgroup_get() and cgroup_put() into cgroup.h so that
> > they can be called from other places.
> > 
> > Signed-off-by: Aditya Kali <adityakali@google.com>
> > Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
> > ---
> >  include/linux/cgroup.h |   21 +++++++++++++++++++++
> >  kernel/cgroup.c        |   22 ----------------------
> >  2 files changed, 21 insertions(+), 22 deletions(-)
> > 
> > diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
> > index 29f0b02..99096be 100644
> > --- a/include/linux/cgroup.h
> > +++ b/include/linux/cgroup.h
> > @@ -231,6 +231,27 @@ void css_task_iter_end(struct css_task_iter *it);
> >  #define css_for_each_descendant_post(pos, css)				\
> >  	for ((pos) = css_next_descendant_post(NULL, (css)); (pos);	\
> >  	     (pos) = css_next_descendant_post((pos), (css)))
> 
> Please insert a blank line here.
> 
> > +/* convenient tests for these bits */
> 
> And I don't think the comment makes sense here.
> 
> > +static inline bool cgroup_is_dead(const struct cgroup *cgrp)
> > +{
> > +	return !(cgrp->self.flags & CSS_ONLINE);
> > +}
> > +
> > +static inline void cgroup_get(struct cgroup *cgrp)
> > +{
> > +	WARN_ON_ONCE(cgroup_is_dead(cgrp));
> > +	css_get(&cgrp->self);
> > +}
> > +
> > +static inline bool cgroup_tryget(struct cgroup *cgrp)
> > +{
> > +	return css_tryget(&cgrp->self);
> > +}
> > +
> > +static inline void cgroup_put(struct cgroup *cgrp)
> > +{
> > +	css_put(&cgrp->self);
> > +}
> 
> So these are being exposed for cgroup NS support.  Hmmm... idk, does
> cgroup NS support needs to be in a spearate file?  The added amount
> isn't that big.  If we split cgroup.c, I'd much prefer to have
> cgroup-internal.h for internally shared stuff than pushing them out to
> cgroup.h.

Yeah, I think it makes more sense to merge them.

thanks,
-serge