On 2012/9/13 15:50, Daniel Wagner wrote: > From: Daniel Wagner <daniel.wagner@xxxxxxxxxxxx> > > CGROUP_BUILTIN_SUBSYS_COUNT is used as start index or stop index when > looping over the subsys array looking either at the builtin or the > module subsystems. Since all the builtin subsystems have an id which > is lower then CGROUP_BUILTIN_SUBSYS_COUNT we know that any module will > have an id larger than CGROUP_BUILTIN_SUBSYS_COUNT. In short the ids > are sorted. > > We are about to change id assignment to happen only at compile time > later in this series. That means we can't rely on the above trick > since all ids will always be defined at compile time. Furthermore, > ordering the builtin subsystems and the module subsystems is not > really necessary. > > So we need a different way to know which subsystem is a builtin or a > module one. We can use the subsys[]->module pointer for this. Any > place where we need to know if a subsys is module we just check for > the pointer. If it is NULL then the subsystem is a builtin one. > > With this we are able to drop the CGROUP_BUILTIN_SUBSYS_COUNT > enum. Though we need to introduce a temporary placeholder so that we > don't get a compilation error when only CONFIG_CGROUP is selected and > no single controller. An empty enum definition is not valid. Later in > this series we are able to remove the placeholder again. > > And with this change we get a fix for this: > > kernel/cgroup.c: In function ‘cgroup_load_subsys’: > kernel/cgroup.c:4326:38: warning: array subscript is below array bounds [-Warray-bounds] > > when CONFIG_CGROUP=y and no built in controller was enabled. > > Signed-off-by: Daniel Wagner <daniel.wagner@xxxxxxxxxxxx> > Acked-by: Tejun Heo <tj@xxxxxxxxxx> > Cc: Gao feng <gaofeng@xxxxxxxxxxxxxx> > Cc: Jamal Hadi Salim <jhs@xxxxxxxxxxxx> > Cc: John Fastabend <john.r.fastabend@xxxxxxxxx> > Cc: Li Zefan <lizefan@xxxxxxxxxx> > Cc: Neil Horman <nhorman@xxxxxxxxxxxxx> > Cc: netdev@xxxxxxxxxxxxxxx > Cc: cgroups@xxxxxxxxxxxxxxx > --- > include/linux/cgroup.h | 2 +- > kernel/cgroup.c | 68 +++++++++++++++++++++++++++++--------------------- > 2 files changed, 41 insertions(+), 29 deletions(-) > Acked-by: Li Zefan <lizefan@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
