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Subject[PATCH v2 1/5] cgroup: split cgroup_base_files[] into cgroup_{dfl|legacy}_base_files[]
From f41924c8f07dcda07a31a08117bac077fde13626 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Fri, 4 Jul 2014 13:06:42 -0400

Currently cgroup_base_files[] contains the cgroup core interface files
for both legacy and default hierarchies with each file tagged with
CFTYPE_INSANE and CFTYPE_ONLY_ON_DFL. This is difficult to read.

Let's separate it out to two separate tables, cgroup_dfl_base_files[]
and cgroup_legacy_base_files[], and use the appropriate one in
cgroup_mkdir() depending on the hierarchy type. This makes tagging
each file unnecessary.

This patch doesn't introduce any behavior changes.

v2: cgroup_dfl_base_files[] was missing the termination entry
triggering WARN in cgroup_init_cftypes() for 0day kernel testing
robot. Fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jet Chen <jet.chen@intel.com>
---
kernel/cgroup.c | 76 ++++++++++++++++++++++++++++++++++++---------------------
1 file changed, 48 insertions(+), 28 deletions(-)

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 1c56924..50858ff 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -180,7 +180,8 @@ static u64 css_serial_nr_next = 1;
*/
static int need_forkexit_callback __read_mostly;

-static struct cftype cgroup_base_files[];
+static struct cftype cgroup_dfl_base_files[];
+static struct cftype cgroup_legacy_base_files[];

static void cgroup_put(struct cgroup *cgrp);
static int rebind_subsystems(struct cgroup_root *dst_root,
@@ -1558,6 +1559,7 @@ static int cgroup_setup_root(struct cgroup_root *root, unsigned int ss_mask)
{
LIST_HEAD(tmp_links);
struct cgroup *root_cgrp = &root->cgrp;
+ struct cftype *base_files;
struct css_set *cset;
int i, ret;

@@ -1595,7 +1597,12 @@ static int cgroup_setup_root(struct cgroup_root *root, unsigned int ss_mask)
}
root_cgrp->kn = root->kf_root->kn;

- ret = cgroup_addrm_files(root_cgrp, cgroup_base_files, true);
+ if (root == &cgrp_dfl_root)
+ base_files = cgroup_dfl_base_files;
+ else
+ base_files = cgroup_legacy_base_files;
+
+ ret = cgroup_addrm_files(root_cgrp, base_files, true);
if (ret)
goto destroy_root;

@@ -3985,7 +3992,8 @@ static int cgroup_clone_children_write(struct cgroup_subsys_state *css,
return 0;
}

-static struct cftype cgroup_base_files[] = {
+/* cgroup core interface files for the default hierarchy */
+static struct cftype cgroup_dfl_base_files[] = {
{
.name = "cgroup.procs",
.seq_start = cgroup_pidlist_start,
@@ -3997,46 +4005,52 @@ static struct cftype cgroup_base_files[] = {
.mode = S_IRUGO | S_IWUSR,
},
{
- .name = "cgroup.clone_children",
- .flags = CFTYPE_INSANE,
- .read_u64 = cgroup_clone_children_read,
- .write_u64 = cgroup_clone_children_write,
- },
- {
- .name = "cgroup.sane_behavior",
- .flags = CFTYPE_INSANE | CFTYPE_ONLY_ON_ROOT,
- .seq_show = cgroup_sane_behavior_show,
- },
- {
.name = "cgroup.controllers",
- .flags = CFTYPE_ONLY_ON_DFL | CFTYPE_ONLY_ON_ROOT,
+ .flags = CFTYPE_ONLY_ON_ROOT,
.seq_show = cgroup_root_controllers_show,
},
{
.name = "cgroup.controllers",
- .flags = CFTYPE_ONLY_ON_DFL | CFTYPE_NOT_ON_ROOT,
+ .flags = CFTYPE_NOT_ON_ROOT,
.seq_show = cgroup_controllers_show,
},
{
.name = "cgroup.subtree_control",
- .flags = CFTYPE_ONLY_ON_DFL,
.seq_show = cgroup_subtree_control_show,
.write = cgroup_subtree_control_write,
},
{
.name = "cgroup.populated",
- .flags = CFTYPE_ONLY_ON_DFL | CFTYPE_NOT_ON_ROOT,
+ .flags = CFTYPE_NOT_ON_ROOT,
.seq_show = cgroup_populated_show,
},
+ { } /* terminate */
+};

- /*
- * Historical crazy stuff. These don't have "cgroup." prefix and
- * don't exist if sane_behavior. If you're depending on these, be
- * prepared to be burned.
- */
+/* cgroup core interface files for the legacy hierarchies */
+static struct cftype cgroup_legacy_base_files[] = {
+ {
+ .name = "cgroup.procs",
+ .seq_start = cgroup_pidlist_start,
+ .seq_next = cgroup_pidlist_next,
+ .seq_stop = cgroup_pidlist_stop,
+ .seq_show = cgroup_pidlist_show,
+ .private = CGROUP_FILE_PROCS,
+ .write = cgroup_procs_write,
+ .mode = S_IRUGO | S_IWUSR,
+ },
+ {
+ .name = "cgroup.clone_children",
+ .read_u64 = cgroup_clone_children_read,
+ .write_u64 = cgroup_clone_children_write,
+ },
+ {
+ .name = "cgroup.sane_behavior",
+ .flags = CFTYPE_ONLY_ON_ROOT,
+ .seq_show = cgroup_sane_behavior_show,
+ },
{
.name = "tasks",
- .flags = CFTYPE_INSANE, /* use "procs" instead */
.seq_start = cgroup_pidlist_start,
.seq_next = cgroup_pidlist_next,
.seq_stop = cgroup_pidlist_stop,
@@ -4047,13 +4061,12 @@ static struct cftype cgroup_base_files[] = {
},
{
.name = "notify_on_release",
- .flags = CFTYPE_INSANE,
.read_u64 = cgroup_read_notify_on_release,
.write_u64 = cgroup_write_notify_on_release,
},
{
.name = "release_agent",
- .flags = CFTYPE_INSANE | CFTYPE_ONLY_ON_ROOT,
+ .flags = CFTYPE_ONLY_ON_ROOT,
.seq_show = cgroup_release_agent_show,
.write = cgroup_release_agent_write,
.max_write_len = PATH_MAX - 1,
@@ -4330,6 +4343,7 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
struct cgroup_root *root;
struct cgroup_subsys *ss;
struct kernfs_node *kn;
+ struct cftype *base_files;
int ssid, ret;

parent = cgroup_kn_lock_live(parent_kn);
@@ -4400,7 +4414,12 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
if (ret)
goto out_destroy;

- ret = cgroup_addrm_files(cgrp, cgroup_base_files, true);
+ if (cgroup_on_dfl(cgrp))
+ base_files = cgroup_dfl_base_files;
+ else
+ base_files = cgroup_legacy_base_files;
+
+ ret = cgroup_addrm_files(cgrp, base_files, true);
if (ret)
goto out_destroy;

@@ -4719,7 +4738,8 @@ int __init cgroup_init(void)
unsigned long key;
int ssid, err;

- BUG_ON(cgroup_init_cftypes(NULL, cgroup_base_files));
+ BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
+ BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));

mutex_lock(&cgroup_mutex);

--
1.9.3


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