cgroup: replace cgroup_subsys->disabled tests with cgroup_subsys_enabled()
Replace cgroup_subsys->disabled tests in controllers with
cgroup_subsys_enabled(). cgroup_subsys_enabled() requires literal
subsys name as its parameter and thus can't be used for cgroup core
which iterates through controllers. For cgroup core, introduce and
use cgroup_ssid_enabled() which uses slower static_key_enabled() test
and can be indexed by subsys ID.
This leaves cgroup_subsys->disabled unused. Removed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Zefan Li <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 3619389..5703ba7 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -224,6 +224,19 @@
static int cgroup_addrm_files(struct cgroup *cgrp, struct cftype cfts[],
bool is_add);
+/**
+ * cgroup_ssid_enabled - cgroup subsys enabled test by subsys ID
+ * @ssid: subsys ID of interest
+ *
+ * cgroup_subsys_enabled() can only be used with literal subsys names which
+ * is fine for individual subsystems but unsuitable for cgroup core. This
+ * is slower static_key_enabled() based test indexed by @ssid.
+ */
+static bool cgroup_ssid_enabled(int ssid)
+{
+ return static_key_enabled(cgroup_subsys_enabled_key[ssid]);
+}
+
/* IDR wrappers which synchronize using cgroup_idr_lock */
static int cgroup_idr_alloc(struct idr *idr, void *ptr, int start, int end,
gfp_t gfp_mask)
@@ -1482,7 +1495,7 @@
for_each_subsys(ss, i) {
if (strcmp(token, ss->legacy_name))
continue;
- if (ss->disabled)
+ if (!cgroup_ssid_enabled(i))
continue;
/* Mutually exclusive option 'all' + subsystem name */
@@ -1513,7 +1526,7 @@
*/
if (all_ss || (!one_ss && !opts->none && !opts->name))
for_each_subsys(ss, i)
- if (!ss->disabled)
+ if (cgroup_ssid_enabled(i))
opts->subsys_mask |= (1 << i);
/*
@@ -2762,7 +2775,8 @@
if (tok[0] == '\0')
continue;
for_each_subsys_which(ss, ssid, &tmp_ss_mask) {
- if (ss->disabled || strcmp(tok + 1, ss->name))
+ if (!cgroup_ssid_enabled(ssid) ||
+ strcmp(tok + 1, ss->name))
continue;
if (*tok == '+') {
@@ -3320,7 +3334,7 @@
{
int ret;
- if (ss->disabled)
+ if (!cgroup_ssid_enabled(ss->id))
return 0;
if (!cfts || cfts[0].name[0] == '\0')
@@ -5082,7 +5096,7 @@
* disabled flag and cftype registration needs kmalloc,
* both of which aren't available during early_init.
*/
- if (ss->disabled)
+ if (!cgroup_ssid_enabled(ssid))
continue;
cgrp_dfl_root.subsys_mask |= 1 << ss->id;
@@ -5217,7 +5231,8 @@
for_each_subsys(ss, i)
seq_printf(m, "%s\t%d\t%d\t%d\n",
ss->legacy_name, ss->root->hierarchy_id,
- atomic_read(&ss->root->nr_cgrps), !ss->disabled);
+ atomic_read(&ss->root->nr_cgrps),
+ cgroup_ssid_enabled(i));
mutex_unlock(&cgroup_mutex);
return 0;
@@ -5508,7 +5523,6 @@
continue;
static_branch_disable(cgroup_subsys_enabled_key[i]);
- ss->disabled = 1;
printk(KERN_INFO "Disabling %s control group subsystem\n",
ss->name);
break;