[PATCH 09/13] cgroup: introduce cgroup_init/exit_cftypes()

From: Tejun Heo
Date: Tue Jan 28 2014 - 18:56:34 EST


Factor out cft->ss initialization into cgroup_init_cftypes() from
cgroup_add_cftypes() and add cft->ss clearing to cgroup_rm_cftypes()
through cgroup_exit_cftypes().

This doesn't make any meaningful difference now but the two new
functions will be expanded during kernfs transition.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
kernel/cgroup.c | 32 +++++++++++++++++++++++++-------
1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index a800e56..5c35f00 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2761,6 +2761,22 @@ static int cgroup_cfts_commit(struct cftype *cfts, bool is_add)
return ret;
}

+static void cgroup_exit_cftypes(struct cftype *cfts)
+{
+ struct cftype *cft;
+
+ for (cft = cfts; cft->name[0] != '\0'; cft++)
+ cft->ss = NULL;
+}
+
+static void cgroup_init_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
+{
+ struct cftype *cft;
+
+ for (cft = cfts; cft->name[0] != '\0'; cft++)
+ cft->ss = ss;
+}
+
/**
* cgroup_add_cftypes - add an array of cftypes to a subsystem
* @ss: target cgroup subsystem
@@ -2778,15 +2794,13 @@ static int cgroup_cfts_commit(struct cftype *cfts, bool is_add)
int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
{
struct cftype_set *set;
- struct cftype *cft;
int ret;

set = kzalloc(sizeof(*set), GFP_KERNEL);
if (!set)
return -ENOMEM;

- for (cft = cfts; cft->name[0] != '\0'; cft++)
- cft->ss = ss;
+ cgroup_init_cftypes(ss, cfts);

cgroup_cfts_prepare();
set->cfts = cfts;
@@ -2811,6 +2825,7 @@ EXPORT_SYMBOL_GPL(cgroup_add_cftypes);
*/
int cgroup_rm_cftypes(struct cftype *cfts)
{
+ struct cftype *found = NULL;
struct cftype_set *set;

if (!cfts || !cfts[0].ss)
@@ -2822,13 +2837,14 @@ int cgroup_rm_cftypes(struct cftype *cfts)
if (set->cfts == cfts) {
list_del(&set->node);
kfree(set);
- cgroup_cfts_commit(cfts, false);
- return 0;
+ found = cfts;
+ break;
}
}

- cgroup_cfts_commit(NULL, false);
- return -ENOENT;
+ cgroup_cfts_commit(found, false);
+ cgroup_exit_cftypes(cfts);
+ return found ? 0 : -ENOENT;
}

/**
@@ -4587,6 +4603,8 @@ int __init cgroup_init(void)
if (err)
return err;

+ cgroup_init_cftypes(NULL, cgroup_base_files);
+
for_each_subsys(ss, i) {
if (!ss->early_init)
cgroup_init_subsys(ss);
--
1.8.5.3

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