vfs: Convert gadgetfs to use the new mount API

Convert the gadgetfs 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>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
cc: linux-usb@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

drivers/usb/gadget/legacy/inode.c

@@ -12,6 +12,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/fs.h>
+#include <linux/fs_context.h>
 #include <linux/pagemap.h>
 #include <linux/uts.h>
 #include <linux/wait.h>
@@ -1990,7 +1991,7 @@ static const struct super_operations gadget_fs_operations = {
 };
 
 static int
-gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
+gadgetfs_fill_super (struct super_block *sb, struct fs_context *fc)
 {
 	struct inode	*inode;
 	struct dev_data	*dev;
@@ -2044,11 +2045,19 @@ gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
 }
 
 /* "mount -t gadgetfs path /dev/gadget" ends up here */
-static struct dentry *
-gadgetfs_mount (struct file_system_type *t, int flags,
-		const char *path, void *opts)
+static int gadgetfs_get_tree(struct fs_context *fc)
 {
-	return mount_single (t, flags, opts, gadgetfs_fill_super);
+	return get_tree_single(fc, gadgetfs_fill_super);
+}
+
+static const struct fs_context_operations gadgetfs_context_ops = {
+	.get_tree	= gadgetfs_get_tree,
+};
+
+static int gadgetfs_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &gadgetfs_context_ops;
+	return 0;
 }
 
 static void
@@ -2068,7 +2077,7 @@ gadgetfs_kill_sb (struct super_block *sb)
 static struct file_system_type gadgetfs_type = {
 	.owner		= THIS_MODULE,
 	.name		= shortname,
-	.mount		= gadgetfs_mount,
+	.init_fs_context = gadgetfs_init_fs_context,
 	.kill_sb	= gadgetfs_kill_sb,
 };
 MODULE_ALIAS_FS("gadgetfs");