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-rw-r--r--kernel/cgroup.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 72fcd3069a90..2097684cf194 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -255,12 +255,17 @@ int cgroup_lock_is_held(void)
EXPORT_SYMBOL_GPL(cgroup_lock_is_held);
+static int css_unbias_refcnt(int refcnt)
+{
+ return refcnt >= 0 ? refcnt : refcnt - CSS_DEACT_BIAS;
+}
+
/* the current nr of refs, always >= 0 whether @css is deactivated or not */
static int css_refcnt(struct cgroup_subsys_state *css)
{
int v = atomic_read(&css->refcnt);
- return v >= 0 ? v : v - CSS_DEACT_BIAS;
+ return css_unbias_refcnt(v);
}
/* convenient tests for these bits */
@@ -4982,10 +4987,12 @@ EXPORT_SYMBOL_GPL(__css_tryget);
void __css_put(struct cgroup_subsys_state *css)
{
struct cgroup *cgrp = css->cgroup;
+ int v;
rcu_read_lock();
- atomic_dec(&css->refcnt);
- switch (css_refcnt(css)) {
+ v = css_unbias_refcnt(atomic_dec_return(&css->refcnt));
+
+ switch (v) {
case 1:
if (notify_on_release(cgrp)) {
set_bit(CGRP_RELEASABLE, &cgrp->flags);