cgroups: subsystem module unloading
Provides support for unloading modular subsystems.
This patch adds a new function cgroup_unload_subsys which is to be used
for removing a loaded subsystem during module deletion. Reference
counting of the subsystems' modules is moved from once (at load time) to
once per attached hierarchy (in parse_cgroupfs_options and
rebind_subsystems) (i.e., 0 or 1).
Signed-off-by: Ben Blum <bblum@andrew.cmu.edu>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 402ce47..2a59d31 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -38,6 +38,7 @@
extern int cgroupstats_build(struct cgroupstats *stats,
struct dentry *dentry);
extern int cgroup_load_subsys(struct cgroup_subsys *ss);
+extern void cgroup_unload_subsys(struct cgroup_subsys *ss);
extern const struct file_operations proc_cgroup_operations;
@@ -271,7 +272,8 @@
/*
* Set of subsystem states, one for each subsystem. This array
* is immutable after creation apart from the init_css_set
- * during subsystem registration (at boot time).
+ * during subsystem registration (at boot time) and modular subsystem
+ * loading/unloading.
*/
struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];