ARM: tegra: dvfs: Add GPU scaling trip-points interfaces
[linux-3.10.git] / kernel / cgroup.c
index c6e77ef..770c43a 100644 (file)
@@ -2098,6 +2098,24 @@ out_free_group_list:
        return retval;
 }
 
+static int cgroup_allow_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
+{
+       struct cgroup_subsys *ss;
+       int ret;
+
+       for_each_subsys(cgrp->root, ss) {
+               if (ss->allow_attach) {
+                       ret = ss->allow_attach(cgrp, tset);
+                       if (ret)
+                               return ret;
+               } else {
+                       return -EACCES;
+               }
+       }
+
+       return 0;
+}
+
 /*
  * Find the task_struct of the task to attach by vpid and pass it along to the
  * function to attach either it or all tasks in its threadgroup. Will lock
@@ -2129,9 +2147,18 @@ retry_find_task:
                if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) &&
                    !uid_eq(cred->euid, tcred->uid) &&
                    !uid_eq(cred->euid, tcred->suid)) {
-                       rcu_read_unlock();
-                       ret = -EACCES;
-                       goto out_unlock_cgroup;
+                       /*
+                        * if the default permission check fails, give each
+                        * cgroup a chance to extend the permission check
+                        */
+                       struct cgroup_taskset tset = { };
+                       tset.single.task = tsk;
+                       tset.single.cgrp = cgrp;
+                       ret = cgroup_allow_attach(cgrp, &tset);
+                       if (ret) {
+                               rcu_read_unlock();
+                               goto out_unlock_cgroup;
+                       }
                }
        } else
                tsk = current;
@@ -2769,13 +2796,17 @@ static void cgroup_cfts_commit(struct cgroup_subsys *ss,
 {
        LIST_HEAD(pending);
        struct cgroup *cgrp, *n;
+       struct super_block *sb = ss->root->sb;
 
        /* %NULL @cfts indicates abort and don't bother if @ss isn't attached */
-       if (cfts && ss->root != &rootnode) {
+       if (cfts && ss->root != &rootnode &&
+           atomic_inc_not_zero(&sb->s_active)) {
                list_for_each_entry(cgrp, &ss->root->allcg_list, allcg_node) {
                        dget(cgrp->dentry);
                        list_add_tail(&cgrp->cft_q_node, &pending);
                }
+       } else {
+               sb = NULL;
        }
 
        mutex_unlock(&cgroup_mutex);
@@ -2798,6 +2829,9 @@ static void cgroup_cfts_commit(struct cgroup_subsys *ss,
                dput(cgrp->dentry);
        }
 
+       if (sb)
+               deactivate_super(sb);
+
        mutex_unlock(&cgroup_cft_mutex);
 }