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-rw-r--r--include/linux/cgroup.h1
-rw-r--r--kernel/cgroup.c22
2 files changed, 23 insertions, 0 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 87479328d46..d8e92223a79 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -233,6 +233,7 @@ int cgroup_is_descendant(const struct cgroup *cont);
struct cgroup_subsys {
struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss,
struct cgroup *cont);
+ void (*pre_destroy)(struct cgroup_subsys *ss, struct cgroup *cont);
void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cont);
int (*can_attach)(struct cgroup_subsys *ss,
struct cgroup *cont, struct task_struct *tsk);
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 4d67a39c58a..4e8b16a8266 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -586,6 +586,21 @@ static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb)
return inode;
}
+/*
+ * Call subsys's pre_destroy handler.
+ * This is called before css refcnt check.
+ */
+
+static void cgroup_call_pre_destroy(struct cgroup *cgrp)
+{
+ struct cgroup_subsys *ss;
+ for_each_subsys(cgrp->root, ss)
+ if (ss->pre_destroy && cgrp->subsys[ss->subsys_id])
+ ss->pre_destroy(ss, cgrp);
+ return;
+}
+
+
static void cgroup_diput(struct dentry *dentry, struct inode *inode)
{
/* is dentry a directory ? if so, kfree() associated cgroup */
@@ -2160,6 +2175,13 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
parent = cgrp->parent;
root = cgrp->root;
sb = root->sb;
+ /*
+ * Call pre_destroy handlers of subsys
+ */
+ cgroup_call_pre_destroy(cgrp);
+ /*
+ * Notify subsyses that rmdir() request comes.
+ */
if (cgroup_has_css_refs(cgrp)) {
mutex_unlock(&cgroup_mutex);