cgroup: kill subsys->can_attach_task(), pre_attach() and attach_task()
These three methods are no longer used. Kill them.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul Menage <paul@paulmenage.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 41ee01e..1b3b841 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1944,13 +1944,6 @@
goto out;
}
}
- if (ss->can_attach_task) {
- retval = ss->can_attach_task(cgrp, tsk);
- if (retval) {
- failed_ss = ss;
- goto out;
- }
- }
}
retval = cgroup_task_migrate(cgrp, oldcgrp, tsk, false);
@@ -1958,10 +1951,6 @@
goto out;
for_each_subsys(root, ss) {
- if (ss->pre_attach)
- ss->pre_attach(cgrp);
- if (ss->attach_task)
- ss->attach_task(cgrp, tsk);
if (ss->attach)
ss->attach(ss, cgrp, &tset);
}
@@ -2093,7 +2082,6 @@
{
int retval, i, group_size, nr_migrating_tasks;
struct cgroup_subsys *ss, *failed_ss = NULL;
- bool cancel_failed_ss = false;
/* guaranteed to be initialized later, but the compiler needs this */
struct css_set *oldcg;
struct cgroupfs_root *root = cgrp->root;
@@ -2188,21 +2176,6 @@
goto out_cancel_attach;
}
}
- /* a callback to be run on every thread in the threadgroup. */
- if (ss->can_attach_task) {
- /* run on each task in the threadgroup. */
- for (i = 0; i < group_size; i++) {
- tc = flex_array_get(group, i);
- if (tc->cgrp == cgrp)
- continue;
- retval = ss->can_attach_task(cgrp, tc->task);
- if (retval) {
- failed_ss = ss;
- cancel_failed_ss = true;
- goto out_cancel_attach;
- }
- }
- }
}
/*
@@ -2234,15 +2207,10 @@
}
/*
- * step 3: now that we're guaranteed success wrt the css_sets, proceed
- * to move all tasks to the new cgroup, calling ss->attach_task for each
- * one along the way. there are no failure cases after here, so this is
- * the commit point.
+ * step 3: now that we're guaranteed success wrt the css_sets,
+ * proceed to move all tasks to the new cgroup. There are no
+ * failure cases after here, so this is the commit point.
*/
- for_each_subsys(root, ss) {
- if (ss->pre_attach)
- ss->pre_attach(cgrp);
- }
for (i = 0; i < group_size; i++) {
tc = flex_array_get(group, i);
/* leave current thread as it is if it's already there */
@@ -2250,18 +2218,11 @@
continue;
retval = cgroup_task_migrate(cgrp, tc->cgrp, tc->task, true);
BUG_ON(retval);
- /* attach each task to each subsystem */
- for_each_subsys(root, ss) {
- if (ss->attach_task)
- ss->attach_task(cgrp, tc->task);
- }
}
/* nothing is sensitive to fork() after this point. */
/*
- * step 4: do expensive, non-thread-specific subsystem callbacks.
- * TODO: if ever a subsystem needs to know the oldcgrp for each task
- * being moved, this call will need to be reworked to communicate that.
+ * step 4: do subsystem attach callbacks.
*/
for_each_subsys(root, ss) {
if (ss->attach)
@@ -2285,11 +2246,8 @@
/* same deal as in cgroup_attach_task */
if (retval) {
for_each_subsys(root, ss) {
- if (ss == failed_ss) {
- if (cancel_failed_ss && ss->cancel_attach)
- ss->cancel_attach(ss, cgrp, &tset);
+ if (ss == failed_ss)
break;
- }
if (ss->cancel_attach)
ss->cancel_attach(ss, cgrp, &tset);
}