path: root/kernel/cgroup.c
diff options
authorTejun Heo <>2016-03-03 09:58:01 -0500
committerTejun Heo <>2016-03-03 09:58:01 -0500
commit5ced2518bd3e3a4f01e2122122211f217cd99f4f (patch)
treefefeccfceacfb805672d3007db8e3e76e51ca744 /kernel/cgroup.c
parent334c3679ec4b2b113c35ebe37d2018b112dd5013 (diff)
cgroup: make cgroup_calc_subtree_ss_mask() take @this_ss_mask
cgroup_calc_subtree_ss_mask() currently takes @cgrp and @subtree_control. @cgrp is used for two purposes - to decide whether it's for default hierarchy and the mask of available subsystems. The former doesn't matter as the results are the same regardless. The latter can be specified directly through a subsystem mask. This patch makes cgroup_calc_subtree_ss_mask() perform the same calculations for both default and legacy hierarchies and take @this_ss_mask for available subsystems. @cgrp is no longer used and dropped. This is to allow using the function in contexts where available controllers can't be decided from the cgroup. v2: cgroup_refres_subtree_ss_mask() is removed by a previous patch. Updated accordingly. Signed-off-by: Tejun Heo <> Acked-by: Zefan Li <>
Diffstat (limited to 'kernel/cgroup.c')
1 files changed, 7 insertions, 10 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 98e644b0a532..58e02e9aa970 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1309,18 +1309,17 @@ static umode_t cgroup_file_mode(const struct cftype *cft)
* cgroup_calc_subtree_ss_mask - calculate subtree_ss_mask
- * @cgrp: the target cgroup
* @subtree_control: the new subtree_control mask to consider
+ * @this_ss_mask: available subsystems
* On the default hierarchy, a subsystem may request other subsystems to be
* enabled together through its ->depends_on mask. In such cases, more
* subsystems than specified in "cgroup.subtree_control" may be enabled.
* This function calculates which subsystems need to be enabled if
- * @subtree_control is to be applied to @cgrp. The returned mask is always
- * a superset of @subtree_control and follows the usual hierarchy rules.
+ * @subtree_control is to be applied while restricted to @this_ss_mask.
-static u16 cgroup_calc_subtree_ss_mask(struct cgroup *cgrp, u16 subtree_control)
+static u16 cgroup_calc_subtree_ss_mask(u16 subtree_control, u16 this_ss_mask)
u16 cur_ss_mask = subtree_control;
struct cgroup_subsys *ss;
@@ -1328,9 +1327,6 @@ static u16 cgroup_calc_subtree_ss_mask(struct cgroup *cgrp, u16 subtree_control)
- if (!cgroup_on_dfl(cgrp))
- return cur_ss_mask;
while (true) {
u16 new_ss_mask = cur_ss_mask;
@@ -1343,7 +1339,7 @@ static u16 cgroup_calc_subtree_ss_mask(struct cgroup *cgrp, u16 subtree_control)
* happen only if some depended-upon subsystems were bound
* to non-default hierarchies.
- new_ss_mask &= cgroup_ss_mask(cgrp);
+ new_ss_mask &= this_ss_mask;
if (new_ss_mask == cur_ss_mask)
@@ -3012,8 +3008,9 @@ static void cgroup_propagate_control(struct cgroup *cgrp)
cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
dsct->subtree_control &= cgroup_control(dsct);
- dsct->subtree_ss_mask = cgroup_calc_subtree_ss_mask(dsct,
- dsct->subtree_control);
+ dsct->subtree_ss_mask =
+ cgroup_calc_subtree_ss_mask(dsct->subtree_control,
+ cgroup_ss_mask(dsct));