From 9e3c017b614b49d8850bdad3c7045b7616a84157 Mon Sep 17 00:00:00 2001
From: Li Zefan <lizf@cn.fujitsu.com>
Date: Thu, 2 Apr 2009 16:57:32 -0700
Subject: [PATCH] --- yaml --- r: 139659 b: refs/heads/master c:
 b4046f00ee7c1e5615261b496cf7309683275b29 h: refs/heads/master i:   139657:
 b327cf936efb955a5c435e609cdaa6684d21c8a2   139655:
 dded36818018f1720b9353545a62e5955b5cab15 v: v3

---
 [refs]                         |  2 +-
 trunk/security/device_cgroup.c | 21 +++++++++++++--------
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/[refs] b/[refs]
index 3652ec830a17..5ae0a1f2b86a 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d969fbe69e07fcceb0558b35d4c75eb046041c5e
+refs/heads/master: b4046f00ee7c1e5615261b496cf7309683275b29
diff --git a/trunk/security/device_cgroup.c b/trunk/security/device_cgroup.c
index 3aacd0fe7179..5fda7df19723 100644
--- a/trunk/security/device_cgroup.c
+++ b/trunk/security/device_cgroup.c
@@ -11,6 +11,7 @@
 #include <linux/uaccess.h>
 #include <linux/seq_file.h>
 #include <linux/rcupdate.h>
+#include <linux/mutex.h>
 
 #define ACC_MKNOD 1
 #define ACC_READ  2
@@ -21,9 +22,11 @@
 #define DEV_CHAR  2
 #define DEV_ALL   4  /* this represents all devices */
 
+static DEFINE_MUTEX(devcgroup_mutex);
+
 /*
  * whitelist locking rules:
- * hold cgroup_lock() for update/read.
+ * hold devcgroup_mutex for update/read.
  * hold rcu_read_lock() for read.
  */
 
@@ -67,7 +70,7 @@ static int devcgroup_can_attach(struct cgroup_subsys *ss,
 }
 
 /*
- * called under cgroup_lock()
+ * called under devcgroup_mutex
  */
 static int dev_whitelist_copy(struct list_head *dest, struct list_head *orig)
 {
@@ -92,7 +95,7 @@ static int dev_whitelist_copy(struct list_head *dest, struct list_head *orig)
 
 /* Stupid prototype - don't bother combining existing entries */
 /*
- * called under cgroup_lock()
+ * called under devcgroup_mutex
  */
 static int dev_whitelist_add(struct dev_cgroup *dev_cgroup,
 			struct dev_whitelist_item *wh)
@@ -130,7 +133,7 @@ static void whitelist_item_free(struct rcu_head *rcu)
 }
 
 /*
- * called under cgroup_lock()
+ * called under devcgroup_mutex
  */
 static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup,
 			struct dev_whitelist_item *wh)
@@ -185,8 +188,10 @@ static struct cgroup_subsys_state *devcgroup_create(struct cgroup_subsys *ss,
 		list_add(&wh->list, &dev_cgroup->whitelist);
 	} else {
 		parent_dev_cgroup = cgroup_to_devcgroup(parent_cgroup);
+		mutex_lock(&devcgroup_mutex);
 		ret = dev_whitelist_copy(&dev_cgroup->whitelist,
 				&parent_dev_cgroup->whitelist);
+		mutex_unlock(&devcgroup_mutex);
 		if (ret) {
 			kfree(dev_cgroup);
 			return ERR_PTR(ret);
@@ -273,7 +278,7 @@ static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft,
  * does the access granted to dev_cgroup c contain the access
  * requested in whitelist item refwh.
  * return 1 if yes, 0 if no.
- * call with c->lock held
+ * call with devcgroup_mutex held
  */
 static int may_access_whitelist(struct dev_cgroup *c,
 				       struct dev_whitelist_item *refwh)
@@ -426,11 +431,11 @@ static int devcgroup_access_write(struct cgroup *cgrp, struct cftype *cft,
 				  const char *buffer)
 {
 	int retval;
-	if (!cgroup_lock_live_group(cgrp))
-		return -ENODEV;
+
+	mutex_lock(&devcgroup_mutex);
 	retval = devcgroup_update_access(cgroup_to_devcgroup(cgrp),
 					 cft->private, buffer);
-	cgroup_unlock();
+	mutex_unlock(&devcgroup_mutex);
 	return retval;
 }