commit f737d95ddfea4df68a36ffc9231db4bf34b06d13
author Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Sun Jan 03 21:16:32 2010 +0900
committer James Morris <jmorris@namei.org> Mon Jan 11 07:57:44 2010 +1100
tree 28a1bf737c96ba8048abcf87a7acfc8412e92a2e
parent fdb8ebb729bbb640e64028a4f579a02ebc405727

TOMOYO: Replace rw_semaphore by mutex.

Since readers no longer use down_read(), writers no longer
need to use rw_semaphore. Replace individual rw_semaphore by
single mutex.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

security/tomoyo/common.c

diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c
index f01b936..642e0e5 100644
--- a/security/tomoyo/common.c
+++ b/security/tomoyo/common.c
@@ -16,6 +16,9 @@
 #include "common.h"
 #include "tomoyo.h"
 
+/* Lock for protecting policy. */
+DEFINE_MUTEX(tomoyo_policy_lock);
+
 /* Has loading policy done? */
 bool tomoyo_policy_loaded;
 
@@ -1086,7 +1089,6 @@
  * # cat /sys/kernel/security/tomoyo/manager
  */
 static LIST_HEAD(tomoyo_policy_manager_list);
-static DECLARE_RWSEM(tomoyo_policy_manager_list_lock);
 
 /**
  * tomoyo_update_manager_entry - Add a manager entry.
@@ -1118,7 +1120,7 @@
 	saved_manager = tomoyo_save_name(manager);
 	if (!saved_manager)
 		return -ENOMEM;
-	down_write(&tomoyo_policy_manager_list_lock);
+	mutex_lock(&tomoyo_policy_lock);
 	list_for_each_entry_rcu(ptr, &tomoyo_policy_manager_list, list) {
 		if (ptr->manager != saved_manager)
 			continue;
@@ -1138,7 +1140,7 @@
 	list_add_tail_rcu(&new_entry->list, &tomoyo_policy_manager_list);
 	error = 0;
  out:
-	up_write(&tomoyo_policy_manager_list_lock);
+	mutex_unlock(&tomoyo_policy_lock);
 	return error;
 }
 
@@ -1315,7 +1317,7 @@
 
 	name.name = domainname;
 	tomoyo_fill_path_info(&name);
-	down_write(&tomoyo_domain_list_lock);
+	mutex_lock(&tomoyo_policy_lock);
 	/* Is there an active domain? */
 	list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
 		/* Never delete tomoyo_kernel_domain */
@@ -1327,7 +1329,7 @@
 		domain->is_deleted = true;
 		break;
 	}
-	up_write(&tomoyo_domain_list_lock);
+	mutex_unlock(&tomoyo_policy_lock);
 	return 0;
 }