Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[safe/jmp/linux-2.6] / kernel / cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 0066092..5a54ff4 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1115,8 +1115,10 @@ static void cgroup_kill_sb(struct super_block *sb) {
        }
        write_unlock(&css_set_lock);
 
-       list_del(&root->root_list);
-       root_count--;
+       if (!list_empty(&root->root_list)) {
+               list_del(&root->root_list);
+               root_count--;
+       }
 
        mutex_unlock(&cgroup_mutex);
 
@@ -2509,7 +2511,7 @@ static int cgroup_clear_css_refs(struct cgroup *cgrp)
        for_each_subsys(cgrp->root, ss) {
                struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id];
                int refcnt;
-               do {
+               while (1) {
                        /* We can only remove a CSS with a refcnt==1 */
                        refcnt = atomic_read(&css->refcnt);
                        if (refcnt > 1) {
@@ -2523,7 +2525,10 @@ static int cgroup_clear_css_refs(struct cgroup *cgrp)
                         * css_tryget() to spin until we set the
                         * CSS_REMOVED bits or abort
                         */
-               } while (atomic_cmpxchg(&css->refcnt, refcnt, 0) != refcnt);
+                       if (atomic_cmpxchg(&css->refcnt, refcnt, 0) == refcnt)
+                               break;
+                       cpu_relax();
+               }
        }
  done:
        for_each_subsys(cgrp->root, ss) {