1 files changed, 15 insertions, 7 deletions

diff --git a/fs/inode.c b/fs/inode.c
index da85e56378f3..9c2b795ccc93 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -295,6 +295,20 @@ static void destroy_inode(struct inode *inode)
                 call_rcu(&inode->i_rcu, i_callback);
 }
 
+void address_space_init_once(struct address_space *mapping)
+{
+        memset(mapping, 0, sizeof(*mapping));
+        INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC);
+        spin_lock_init(&mapping->tree_lock);
+        spin_lock_init(&mapping->i_mmap_lock);
+        INIT_LIST_HEAD(&mapping->private_list);
+        spin_lock_init(&mapping->private_lock);
+        INIT_RAW_PRIO_TREE_ROOT(&mapping->i_mmap);
+        INIT_LIST_HEAD(&mapping->i_mmap_nonlinear);
+        mutex_init(&mapping->unmap_mutex);
+}
+EXPORT_SYMBOL(address_space_init_once);
+
 /*
  * These are initializations that only need to be done
  * once, because the fields are idempotent across use
@@ -308,13 +322,7 @@ void inode_init_once(struct inode *inode)
         INIT_LIST_HEAD(&inode->i_devices);
         INIT_LIST_HEAD(&inode->i_wb_list);
         INIT_LIST_HEAD(&inode->i_lru);
-        INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
-        spin_lock_init(&inode->i_data.tree_lock);
-        spin_lock_init(&inode->i_data.i_mmap_lock);
-        INIT_LIST_HEAD(&inode->i_data.private_list);
-        spin_lock_init(&inode->i_data.private_lock);
-        INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap);
-        INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear);
+        address_space_init_once(&inode->i_data);
         i_size_ordered_init(inode);
 #ifdef CONFIG_FSNOTIFY
         INIT_HLIST_HEAD(&inode->i_fsnotify_marks);