[PATCH v3 3/3] init/do_mounts.c: fix rootfs_fs_type with ramfs

[menglong8 . dong]

From: Menglong Dong <dong.menglong@xxxxxxxxxx>

As for the existence of 'user root' which is introduced in previous
patch, 'rootfs_fs_type', which is used as the root of mount tree,
is not used directly any more. So it make no sense to make it tmpfs
while 'INITRAMFS_USER_ROOT' is enabled.

Make 'rootfs_fs_type' ramfs when 'INITRAMFS_USER_ROOT' enabled.

Signed-off-by: Menglong Dong <dong.menglong@xxxxxxxxxx>
---
 include/linux/init.h |  5 +++++
 init/do_mounts.c     | 10 +++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/include/linux/init.h b/include/linux/init.h
index 045ad1650ed1..d65b12fe438c 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -148,7 +148,12 @@ extern unsigned int reset_devices;
 /* used by init/main.c */
 void setup_arch(char **);
 void prepare_namespace(void);
+#ifndef CONFIG_INITRAMFS_USER_ROOT
 void __init init_rootfs(void);
+#else
+static inline void __init init_rootfs(void) { }
+#endif
+
 extern struct file_system_type rootfs_fs_type;
 
 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 2fd168cca480..74f5b0fc8bdf 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -716,7 +716,14 @@ void __init init_user_rootfs(void)
 		}
 	}
 }
-#endif
+
+struct file_system_type rootfs_fs_type = {
+	.name		= "rootfs",
+	.init_fs_context = ramfs_init_fs_context,
+	.kill_sb	= kill_litter_super,
+};
+
+#else
 
 static bool is_tmpfs;
 static int rootfs_init_fs_context(struct fs_context *fc)
@@ -739,3 +746,4 @@ void __init init_rootfs(void)
 		(!root_fs_names || strstr(root_fs_names, "tmpfs")))
 		is_tmpfs = true;
 }
+#endif
-- 
2.32.0.rc0