Linux 3.11-rc5

[linux-imx.git] / kernel / cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 0e0b20b8c5db172e8dc07fe4de10358c19939d60..781845a013ab23c8f99f2c2153c70c9fd679c45d 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1845,36 +1845,43 @@ out:
 EXPORT_SYMBOL_GPL(cgroup_path);
 
 /**
- * task_cgroup_path_from_hierarchy - cgroup path of a task on a hierarchy
+ * task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
  * @task: target task
- * @hierarchy_id: the hierarchy to look up @task's cgroup from
  * @buf: the buffer to write the path into
  * @buflen: the length of the buffer
  *
- * Determine @task's cgroup on the hierarchy specified by @hierarchy_id and
- * copy its path into @buf.  This function grabs cgroup_mutex and shouldn't
- * be used inside locks used by cgroup controller callbacks.
+ * Determine @task's cgroup on the first (the one with the lowest non-zero
+ * hierarchy_id) cgroup hierarchy and copy its path into @buf.  This
+ * function grabs cgroup_mutex and shouldn't be used inside locks used by
+ * cgroup controller callbacks.
+ *
+ * Returns 0 on success, fails with -%ENAMETOOLONG if @buflen is too short.
  */
-int task_cgroup_path_from_hierarchy(struct task_struct *task, int hierarchy_id,
-                                   char *buf, size_t buflen)
+int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
 {
        struct cgroupfs_root *root;
-       struct cgroup *cgrp = NULL;
-       int ret = -ENOENT;
+       struct cgroup *cgrp;
+       int hierarchy_id = 1, ret = 0;
+
+       if (buflen < 2)
+               return -ENAMETOOLONG;
 
        mutex_lock(&cgroup_mutex);
 
-       root = idr_find(&cgroup_hierarchy_idr, hierarchy_id);
+       root = idr_get_next(&cgroup_hierarchy_idr, &hierarchy_id);
+
        if (root) {
                cgrp = task_cgroup_from_root(task, root);
                ret = cgroup_path(cgrp, buf, buflen);
+       } else {
+               /* if no hierarchy exists, everyone is in "/" */
+               memcpy(buf, "/", 2);
        }
 
        mutex_unlock(&cgroup_mutex);
-
        return ret;
 }
-EXPORT_SYMBOL_GPL(task_cgroup_path_from_hierarchy);
+EXPORT_SYMBOL_GPL(task_cgroup_path);
 
 /*
  * Control Group taskset
@@ -4328,8 +4335,10 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
                }
 
                err = percpu_ref_init(&css->refcnt, css_release);
-               if (err)
+               if (err) {
+                       ss->css_free(cgrp);
                        goto err_free_all;
+               }
 
                init_cgroup_css(css, ss, cgrp);