diff options
-rw-r--r-- | include/linux/cgroup.h | 17 | ||||
-rw-r--r-- | kernel/cgroup.c | 28 |
2 files changed, 28 insertions, 17 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 75c6ec1ba1ba..5f76829dd75e 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -44,14 +44,25 @@ extern void cgroup_unload_subsys(struct cgroup_subsys *ss); extern const struct file_operations proc_cgroup_operations; -/* Define the enumeration of all builtin cgroup subsystems */ +/* + * Define the enumeration of all cgroup subsystems. + * + * We define ids for builtin subsystems and then modular ones. + */ #define SUBSYS(_x) _x ## _subsys_id, -#define IS_SUBSYS_ENABLED(option) IS_ENABLED(option) enum cgroup_subsys_id { +#define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option) +#include <linux/cgroup_subsys.h> +#undef IS_SUBSYS_ENABLED + CGROUP_BUILTIN_SUBSYS_COUNT, + + __CGROUP_SUBSYS_TEMP_PLACEHOLDER = CGROUP_BUILTIN_SUBSYS_COUNT - 1, + +#define IS_SUBSYS_ENABLED(option) IS_MODULE(option) #include <linux/cgroup_subsys.h> +#undef IS_SUBSYS_ENABLED CGROUP_SUBSYS_COUNT, }; -#undef IS_SUBSYS_ENABLED #undef SUBSYS /* Per-subsystem/per-cgroup state maintained by the system. */ diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 9df799d5d31c..7a6c4c72ca55 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4940,17 +4940,17 @@ void cgroup_post_fork(struct task_struct *child) * and addition to css_set. */ if (need_forkexit_callback) { - for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { + /* + * fork/exit callbacks are supported only for builtin + * subsystems, and the builtin section of the subsys + * array is immutable, so we don't need to lock the + * subsys array here. On the other hand, modular section + * of the array can be freed at module unload, so we + * can't touch that. + */ + for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; - /* - * fork/exit callbacks are supported only for - * builtin subsystems and we don't need further - * synchronization as they never go away. - */ - if (!ss || ss->module) - continue; - if (ss->fork) ss->fork(child); } @@ -5015,13 +5015,13 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks) tsk->cgroups = &init_css_set; if (run_callbacks && need_forkexit_callback) { - for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { + /* + * fork/exit callbacks are supported only for builtin + * subsystems, see cgroup_post_fork() for details. + */ + for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; - /* modular subsystems can't use callbacks */ - if (!ss || ss->module) - continue; - if (ss->exit) { struct cgroup *old_cgrp = rcu_dereference_raw(cg->subsys[i])->cgroup; |