Merge tag 'for-4.20/block-20181021' of git://git.kernel.dk/linux-block
[muen/linux.git] / kernel / cgroup / cgroup.c
index 48fb22e494671e121d5e75ca8924cbe522a2b2e4..4c1cf0969a80e9c63d111ab60e23b180f402cde0 100644 (file)
@@ -2866,11 +2866,12 @@ restart:
 }
 
 /**
- * cgroup_save_control - save control masks of a subtree
+ * cgroup_save_control - save control masks and dom_cgrp of a subtree
  * @cgrp: root of the target subtree
  *
- * Save ->subtree_control and ->subtree_ss_mask to the respective old_
- * prefixed fields for @cgrp's subtree including @cgrp itself.
+ * Save ->subtree_control, ->subtree_ss_mask and ->dom_cgrp to the
+ * respective old_ prefixed fields for @cgrp's subtree including @cgrp
+ * itself.
  */
 static void cgroup_save_control(struct cgroup *cgrp)
 {
@@ -2880,6 +2881,7 @@ static void cgroup_save_control(struct cgroup *cgrp)
        cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
                dsct->old_subtree_control = dsct->subtree_control;
                dsct->old_subtree_ss_mask = dsct->subtree_ss_mask;
+               dsct->old_dom_cgrp = dsct->dom_cgrp;
        }
 }
 
@@ -2905,11 +2907,12 @@ static void cgroup_propagate_control(struct cgroup *cgrp)
 }
 
 /**
- * cgroup_restore_control - restore control masks of a subtree
+ * cgroup_restore_control - restore control masks and dom_cgrp of a subtree
  * @cgrp: root of the target subtree
  *
- * Restore ->subtree_control and ->subtree_ss_mask from the respective old_
- * prefixed fields for @cgrp's subtree including @cgrp itself.
+ * Restore ->subtree_control, ->subtree_ss_mask and ->dom_cgrp from the
+ * respective old_ prefixed fields for @cgrp's subtree including @cgrp
+ * itself.
  */
 static void cgroup_restore_control(struct cgroup *cgrp)
 {
@@ -2919,6 +2922,7 @@ static void cgroup_restore_control(struct cgroup *cgrp)
        cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) {
                dsct->subtree_control = dsct->old_subtree_control;
                dsct->subtree_ss_mask = dsct->old_subtree_ss_mask;
+               dsct->dom_cgrp = dsct->old_dom_cgrp;
        }
 }
 
@@ -3226,6 +3230,8 @@ static int cgroup_enable_threaded(struct cgroup *cgrp)
 {
        struct cgroup *parent = cgroup_parent(cgrp);
        struct cgroup *dom_cgrp = parent->dom_cgrp;
+       struct cgroup *dsct;
+       struct cgroup_subsys_state *d_css;
        int ret;
 
        lockdep_assert_held(&cgroup_mutex);
@@ -3255,12 +3261,13 @@ static int cgroup_enable_threaded(struct cgroup *cgrp)
         */
        cgroup_save_control(cgrp);
 
-       cgrp->dom_cgrp = dom_cgrp;
+       cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp)
+               if (dsct == cgrp || cgroup_is_threaded(dsct))
+                       dsct->dom_cgrp = dom_cgrp;
+
        ret = cgroup_apply_control(cgrp);
        if (!ret)
                parent->nr_threaded_children++;
-       else
-               cgrp->dom_cgrp = cgrp;
 
        cgroup_finalize_control(cgrp, ret);
        return ret;