commit 5a5cf5cb30d7815c01035fde4b84edef85d11c68
author Christian Brauner <christian.brauner@ubuntu.com> Wed Feb 05 14:26:20 2020 +0100
committer Tejun Heo <tj@kernel.org> Wed Feb 12 17:57:51 2020 -0500
tree 8902eaa6a853cad870a57a35fef4c861b4c62740
parent 17703097f3456498e6424614571648c6452f4d34

cgroup: refactor fork helpers

This refactors the fork helpers so they can be easily modified in the
next patches. The patch just moves the cgroup threadgroup rwsem grab and
release into the helpers. They don't need to be directly exposed in fork.c.

Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: cgroups@vger.kernel.org
Acked-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/fork.c

diff --git a/kernel/fork.c b/kernel/fork.c
index 60a1295..9245b6e 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2174,7 +2174,6 @@
 	INIT_LIST_HEAD(&p->thread_group);
 	p->task_works = NULL;
 
-	cgroup_threadgroup_change_begin(current);
 	/*
 	 * Ensure that the cgroup subsystem policies allow the new process to be
 	 * forked. It should be noted the the new process's css_set can be changed
@@ -2183,7 +2182,7 @@
 	 */
 	retval = cgroup_can_fork(p);
 	if (retval)
-		goto bad_fork_cgroup_threadgroup_change_end;
+		goto bad_fork_put_pidfd;
 
 	/*
 	 * From this point on we must avoid any synchronous user-space
@@ -2289,7 +2288,6 @@
 
 	proc_fork_connector(p);
 	cgroup_post_fork(p);
-	cgroup_threadgroup_change_end(current);
 	perf_event_fork(p);
 
 	trace_task_newtask(p, clone_flags);
@@ -2301,8 +2299,6 @@
 	spin_unlock(&current->sighand->siglock);
 	write_unlock_irq(&tasklist_lock);
 	cgroup_cancel_fork(p);
-bad_fork_cgroup_threadgroup_change_end:
-	cgroup_threadgroup_change_end(current);
 bad_fork_put_pidfd:
 	if (clone_flags & CLONE_PIDFD) {
 		fput(pidfile);