From: Rob Landley Subject: [PATCH 2/5] initmpfs: Move bdi setup from init_rootfs to init_ramfs To: linux-kernel@vger.kernel.org Cc: Al Viro Cc: "Eric W. Biederman" From: Rob Landley Even though ramfs hasn't got a backing device, commit e0bf68ddec4f added one anyway, and put the initialization in init_rootfs() since that's the first user, leaving it out of init_ramfs() to avoid duplication. But initmpfs uses init_tmpfs() instead, so move the init into the filesystem's init function, add a "once" guard to prevent duplicate initialization, and call the filesystem init from rootfs init. This goes part of the way to allowing ramfs to be built as a module. Signed-off-by: Rob Landley --- fs/ramfs/inode.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-) --- initold/fs/ramfs/inode.c 2013-06-28 15:12:03.205879730 -0500 +++ initold2/fs/ramfs/inode.c 2013-06-28 15:12:12.425880115 -0500 @@ -277,21 +277,36 @@ static int __init init_ramfs_fs(void) { - return register_filesystem(&ramfs_fs_type); + static int once; + int err; + + if (once) + return 0; + else + once++; + + err = bdi_init(&ramfs_backing_dev_info); + if (err) + return err; + + err = register_filesystem(&ramfs_fs_type); + if (err) + bdi_destroy(&ramfs_backing_dev_info); + + return err; } module_init(init_ramfs_fs) int __init init_rootfs(void) { - int err; + int err = register_filesystem(&rootfs_fs_type); - err = bdi_init(&ramfs_backing_dev_info); if (err) return err; - err = register_filesystem(&rootfs_fs_type); + err = init_ramfs_fs(); if (err) - bdi_destroy(&ramfs_backing_dev_info); + unregister_filesystem(&rootfs_fs_type); return err; }