vfs: Convert securityfs to use the new mount API

Convert the securityfs filesystem to the new internal mount API as the old
one will be obsoleted and removed.  This allows greater flexibility in
communication of mount parameters between userspace, the VFS and the
filesystem.

See Documentation/filesystems/mount_api.txt for more information.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-security-module@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

security/inode.c

@@ -16,6 +16,7 @@
 #include <linux/sysfs.h>
 #include <linux/kobject.h>
 #include <linux/fs.h>
+#include <linux/fs_context.h>
 #include <linux/mount.h>
 #include <linux/pagemap.h>
 #include <linux/init.h>
@@ -39,7 +40,7 @@ static const struct super_operations securityfs_super_operations = {
 	.free_inode	= securityfs_free_inode,
 };
 
-static int fill_super(struct super_block *sb, void *data, int silent)
+static int securityfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	static const struct tree_descr files[] = {{""}};
 	int error;
@@ -53,17 +54,25 @@ static int fill_super(struct super_block *sb, void *data, int silent)
 	return 0;
 }
 
-static struct dentry *get_sb(struct file_system_type *fs_type,
-		  int flags, const char *dev_name,
-		  void *data)
+static int securityfs_get_tree(struct fs_context *fc)
 {
-	return mount_single(fs_type, flags, data, fill_super);
+	return get_tree_single(fc, securityfs_fill_super);
+}
+
+static const struct fs_context_operations securityfs_context_ops = {
+	.get_tree	= securityfs_get_tree,
+};
+
+static int securityfs_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &securityfs_context_ops;
+	return 0;
 }
 
 static struct file_system_type fs_type = {
 	.owner =	THIS_MODULE,
 	.name =		"securityfs",
-	.mount =	get_sb,
+	.init_fs_context = securityfs_init_fs_context,
 	.kill_sb =	kill_litter_super,
 };