Merge branch 'for-3.10-fixes' into for-3.11

Merging to receive 7805d000db ("cgroup: fix a subtle bug in descendant
pre-order walk") so that further iterator updates can build upon it.

Signed-off-by: Tejun Heo <tj@kernel.org>

2 files changed, 9 insertions, 11 deletions

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 4f6f5138c340..1df5f699be61 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -709,7 +709,7 @@ struct cgroup *cgroup_rightmost_descendant(struct cgroup *pos);
  *
  * If a subsystem synchronizes against the parent in its ->css_online() and
  * before starting iterating, and synchronizes against @pos on each
- * iteration, any descendant cgroup which finished ->css_offline() is
+ * iteration, any descendant cgroup which finished ->css_online() is
  * guaranteed to be visible in the future iterations.
  *
  * In other words, the following guarantees that a descendant can't escape
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 6b2b1d945df2..a19419f4af1a 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2736,13 +2736,14 @@ static int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys,
                 goto out;
         }
 
+        cfe->type = (void *)cft;
+        cfe->dentry = dentry;
+        dentry->d_fsdata = cfe;
+        simple_xattrs_init(&cfe->xattrs);
+
         mode = cgroup_file_mode(cft);
         error = cgroup_create_file(dentry, mode | S_IFREG, cgrp->root->sb);
         if (!error) {
-                cfe->type = (void *)cft;
-                cfe->dentry = dentry;
-                dentry->d_fsdata = cfe;
-                simple_xattrs_init(&cfe->xattrs);
                 list_add_tail(&cfe->node, &parent->files);
                 cfe = NULL;
         }
@@ -2990,11 +2991,8 @@ struct cgroup *cgroup_next_descendant_pre(struct cgroup *pos,
         WARN_ON_ONCE(!rcu_read_lock_held());
 
         /* if first iteration, pretend we just visited @cgroup */
-        if (!pos) {
-                if (list_empty(&cgroup->children))
-                        return NULL;
+        if (!pos)
                 pos = cgroup;
-        }
 
         /* visit the first child if exists */
         next = list_first_or_null_rcu(&pos->children, struct cgroup, sibling);
@@ -3002,14 +3000,14 @@ struct cgroup *cgroup_next_descendant_pre(struct cgroup *pos,
                 return next;
 
         /* no child, visit my or the closest ancestor's next sibling */
-        do {
+        while (pos != cgroup) {
                 next = list_entry_rcu(pos->sibling.next, struct cgroup,
                                       sibling);
                 if (&next->sibling != &pos->parent->children)
                         return next;
 
                 pos = pos->parent;
-        } while (pos != cgroup);
+        }
 
         return NULL;
 }