Merge branches 'clk-range', 'clk-uniphier', 'clk-apple' and 'clk-qcom' into clk-next

[linux-2.6-microblaze.git] / kernel / cgroup / cpuset.c

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index dc653ab..4c7254e 100644 (file)
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -590,6 +590,35 @@ static inline void free_cpuset(struct cpuset *cs)
        kfree(cs);
 }
 
+/*
+ * validate_change_legacy() - Validate conditions specific to legacy (v1)
+ *                            behavior.
+ */
+static int validate_change_legacy(struct cpuset *cur, struct cpuset *trial)
+{
+       struct cgroup_subsys_state *css;
+       struct cpuset *c, *par;
+       int ret;
+
+       WARN_ON_ONCE(!rcu_read_lock_held());
+
+       /* Each of our child cpusets must be a subset of us */
+       ret = -EBUSY;
+       cpuset_for_each_child(c, css, cur)
+               if (!is_cpuset_subset(c, trial))
+                       goto out;
+
+       /* On legacy hierarchy, we must be a subset of our parent cpuset. */
+       ret = -EACCES;
+       par = parent_cs(cur);
+       if (par && !is_cpuset_subset(trial, par))
+               goto out;
+
+       ret = 0;
+out:
+       return ret;
+}
+
 /*
  * validate_change() - Used to validate that any proposed cpuset change
  *                    follows the structural rules for cpusets.
@@ -614,20 +643,21 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial)
 {
        struct cgroup_subsys_state *css;
        struct cpuset *c, *par;
-       int ret;
-
-       /* The checks don't apply to root cpuset */
-       if (cur == &top_cpuset)
-               return 0;
+       int ret = 0;
 
        rcu_read_lock();
-       par = parent_cs(cur);
 
-       /* On legacy hierarchy, we must be a subset of our parent cpuset. */
-       ret = -EACCES;
-       if (!is_in_v2_mode() && !is_cpuset_subset(trial, par))
+       if (!is_in_v2_mode())
+               ret = validate_change_legacy(cur, trial);
+       if (ret)
+               goto out;
+
+       /* Remaining checks don't apply to root cpuset */
+       if (cur == &top_cpuset)
                goto out;
 
+       par = parent_cs(cur);
+
        /*
         * If either I or some sibling (!= me) is exclusive, we can't
         * overlap
@@ -1175,9 +1205,7 @@ enum subparts_cmd {
  *
  * Because of the implicit cpu exclusive nature of a partition root,
  * cpumask changes that violates the cpu exclusivity rule will not be
- * permitted when checked by validate_change(). The validate_change()
- * function will also prevent any changes to the cpu list if it is not
- * a superset of children's cpu lists.
+ * permitted when checked by validate_change().
  */
 static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
                                          struct cpumask *newmask,
@@ -1522,10 +1550,15 @@ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs,
        struct cpuset *sibling;
        struct cgroup_subsys_state *pos_css;
 
+       percpu_rwsem_assert_held(&cpuset_rwsem);
+
        /*
         * Check all its siblings and call update_cpumasks_hier()
         * if their use_parent_ecpus flag is set in order for them
         * to use the right effective_cpus value.
+        *
+        * The update_cpumasks_hier() function may sleep. So we have to
+        * release the RCU read lock before calling it.
         */
        rcu_read_lock();
        cpuset_for_each_child(sibling, pos_css, parent) {
@@ -1533,8 +1566,13 @@ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs,
                        continue;
                if (!sibling->use_parent_ecpus)
                        continue;
+               if (!css_tryget_online(&sibling->css))
+                       continue;
 
+               rcu_read_unlock();
                update_cpumasks_hier(sibling, tmp);
+               rcu_read_lock();
+               css_put(&sibling->css);
        }
        rcu_read_unlock();
 }
@@ -1607,8 +1645,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
         * Make sure that subparts_cpus is a subset of cpus_allowed.
         */
        if (cs->nr_subparts_cpus) {
-               cpumask_andnot(cs->subparts_cpus, cs->subparts_cpus,
-                              cs->cpus_allowed);
+               cpumask_and(cs->subparts_cpus, cs->subparts_cpus, cs->cpus_allowed);
                cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus);
        }
        spin_unlock_irq(&callback_lock);