cgroup: move check_for_release() invocation

To trigger release agent when the last task leaves the cgroup,
check_for_release() is called from put_css_set_locked(); however,
css_set being unlinked is being decoupled from task leaving the cgroup
and the correct condition to test is cgroup->nr_populated dropping to
zero which check_for_release() is already updated to test.

This patch moves check_for_release() invocation from
put_css_set_locked() to cgroup_update_populated().

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 1 insertions, 7 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 435aa686567b..855313d01e85 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -623,6 +623,7 @@ static void cgroup_update_populated(struct cgroup *cgrp, bool populated)
                 if (!trigger)
                         break;
 
+                check_for_release(cgrp);
                 cgroup_file_notify(&cgrp->events_file);
 
                 cgrp = cgroup_parent(cgrp);
@@ -686,15 +687,8 @@ static void put_css_set_locked(struct css_set *cset)
         css_set_count--;
 
         list_for_each_entry_safe(link, tmp_link, &cset->cgrp_links, cgrp_link) {
-                struct cgroup *cgrp = link->cgrp;
-
                 list_del(&link->cset_link);
                 list_del(&link->cgrp_link);
-
-                /* @cgrp can't go away while we're holding css_set_rwsem */
-                if (list_empty(&cgrp->cset_links))
-                        check_for_release(cgrp);
-
                 kfree(link);
         }