int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
{
int retval = 0;
- struct cgroup_subsys *ss;
+ struct cgroup_subsys *ss, *failed_ss = NULL;
struct cgroup *oldcgrp;
struct css_set *cg;
struct css_set *newcg;
for_each_subsys(root, ss) {
if (ss->can_attach) {
retval = ss->can_attach(ss, cgrp, tsk, false);
- if (retval)
- return retval;
+ if (retval) {
+ /*
+ * Remember on which subsystem the can_attach()
+ * failed, so that we only call cancel_attach()
+ * against the subsystems whose can_attach()
+ * succeeded. (See below)
+ */
+ failed_ss = ss;
+ goto out;
+ }
}
}
*/
newcg = find_css_set(cg, cgrp);
put_css_set(cg);
- if (!newcg)
- return -ENOMEM;
+ if (!newcg) {
+ retval = -ENOMEM;
+ goto out;
+ }
task_lock(tsk);
if (tsk->flags & PF_EXITING) {
task_unlock(tsk);
put_css_set(newcg);
- return -ESRCH;
+ retval = -ESRCH;
+ goto out;
}
rcu_assign_pointer(tsk->cgroups, newcg);
task_unlock(tsk);
* is no longer empty.
*/
cgroup_wakeup_rmdir_waiter(cgrp);
- return 0;
+out:
+ if (retval) {
+ for_each_subsys(root, ss) {
+ if (ss == failed_ss)
+ /*
+ * This subsystem was the one that failed the
+ * can_attach() check earlier, so we don't need
+ * to call cancel_attach() against it or any
+ * remaining subsystems.
+ */
+ break;
+ if (ss->cancel_attach)
+ ss->cancel_attach(ss, cgrp, tsk, false);
+ }
+ }
+ return retval;
}
/*