configfs: Convert subsystem semaphore to mutex

Convert the su_sem member of struct configfs_subsystem to a struct
mutex, as that's what it is. Also convert all the users and update
Documentation/configfs.txt and Documentation/configfs_example.c
accordingly.

[ Conflict in fs/dlm/config.c with commit
  3168b0780d06ace875696f8a648d04d6089654e5 manually resolved. --Mark ]

Inspired-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 5e6e37e58f36..d3b1dbb9b5b8 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -562,7 +562,7 @@ static int populate_groups(struct config_group *group)
 
 /*
  * All of link_obj/unlink_obj/link_group/unlink_group require that
- * subsys->su_sem is held.
+ * subsys->su_mutex is held.
  */
 
 static void unlink_obj(struct config_item *item)
@@ -783,7 +783,7 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 
         snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
 
-        down(&subsys->su_sem);
+        mutex_lock(&subsys->su_mutex);
         group = NULL;
         item = NULL;
         if (type->ct_group_ops->make_group) {
@@ -797,7 +797,7 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
                 if (item)
                         link_obj(parent_item, item);
         }
-        up(&subsys->su_sem);
+        mutex_unlock(&subsys->su_mutex);
 
         kfree(name);
         if (!item) {
@@ -841,13 +841,13 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 out_unlink:
         if (ret) {
                 /* Tear down everything we built up */
-                down(&subsys->su_sem);
+                mutex_lock(&subsys->su_mutex);
                 if (group)
                         unlink_group(group);
                 else
                         unlink_obj(item);
                 client_drop_item(parent_item, item);
-                up(&subsys->su_sem);
+                mutex_unlock(&subsys->su_mutex);
 
                 if (module_got)
                         module_put(owner);
@@ -910,17 +910,17 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
         if (sd->s_type & CONFIGFS_USET_DIR) {
                 configfs_detach_group(item);
 
-                down(&subsys->su_sem);
+                mutex_lock(&subsys->su_mutex);
                 unlink_group(to_config_group(item));
         } else {
                 configfs_detach_item(item);
 
-                down(&subsys->su_sem);
+                mutex_lock(&subsys->su_mutex);
                 unlink_obj(item);
         }
 
         client_drop_item(parent_item, item);
-        up(&subsys->su_sem);
+        mutex_unlock(&subsys->su_mutex);
 
         /* Drop our reference from above */
         config_item_put(item);