vfs: Convert aio to use the new mount API

Convert the aio 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: Benjamin LaHaise <bcrl@kvack.org>
cc: linux-aio@kvack.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/aio.c

@@ -42,6 +42,7 @@
 #include <linux/ramfs.h>
 #include <linux/percpu-refcount.h>
 #include <linux/mount.h>
+#include <linux/pseudo_fs.h>
 
 #include <asm/kmap_types.h>
 #include <linux/uaccess.h>
@@ -249,14 +250,12 @@ static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
 	return file;
 }
 
-static struct dentry *aio_mount(struct file_system_type *fs_type,
-				int flags, const char *dev_name, void *data)
+static int aio_init_fs_context(struct fs_context *fc)
 {
-	struct dentry *root = mount_pseudo(fs_type, NULL, NULL, AIO_RING_MAGIC);
-
-	if (!IS_ERR(root))
-		root->d_sb->s_iflags |= SB_I_NOEXEC;
-	return root;
+	if (!init_pseudo(fc, AIO_RING_MAGIC))
+		return -ENOMEM;
+	fc->s_iflags |= SB_I_NOEXEC;
+	return 0;
 }
 
 /* aio_setup
@@ -267,7 +266,7 @@ static int __init aio_setup(void)
 {
 	static struct file_system_type aio_fs = {
 		.name		= "aio",
-		.mount		= aio_mount,
+		.init_fs_context = aio_init_fs_context,
 		.kill_sb	= kill_anon_super,
 	};
 	aio_mnt = kern_mount(&aio_fs);