[CFT][PATCH 09/10] sysfs: Create mountpoints with sysfs_create_empty_dir

[ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)]

This allows for better documentation in the code and
it allows for a simpler and fully correct version of
fs_fully_visible to be written.

The mount points converted and their filesystems are:
/sys/hypervisor/s390/       s390_hypfs
/sys/kernel/config/         configfs
/sys/kernel/debug/          debugfs
/sys/firmware/efi/efivars/  efivarfs
/sys/fs/fuse/connections/   fusectl
/sys/fs/pstore/             pstore
/sys/kernel/tracing/        tracefs
/sys/fs/cgroup/             cgroup
/sys/kernel/security/       securityfs
/sys/fs/selinux/            selinuxfs
/sys/fs/smackfs/            smackfs

Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Signed-off-by: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
---
 arch/s390/hypfs/inode.c      | 12 ++++--------
 drivers/firmware/efi/efi.c   |  6 ++----
 fs/configfs/mount.c          | 10 ++++------
 fs/debugfs/inode.c           | 11 ++++-------
 fs/fuse/inode.c              |  9 +++------
 fs/pstore/inode.c            | 12 ++++--------
 fs/tracefs/inode.c           |  6 ++----
 kernel/cgroup.c              | 10 ++++------
 security/inode.c             | 10 ++++------
 security/selinux/selinuxfs.c | 11 +++++------
 security/smack/smackfs.c     |  8 ++++----
 11 files changed, 40 insertions(+), 65 deletions(-)

diff --git a/arch/s390/hypfs/inode.c b/arch/s390/hypfs/inode.c
index d3f896a35b98..d943d36076cc 100644
--- a/arch/s390/hypfs/inode.c
+++ b/arch/s390/hypfs/inode.c
@@ -456,8 +456,6 @@ static const struct super_operations hypfs_s_ops = {
 	.show_options	= hypfs_show_options,
 };
 
-static struct kobject *s390_kobj;
-
 static int __init hypfs_init(void)
 {
 	int rc;
@@ -481,18 +479,16 @@ static int __init hypfs_init(void)
 		rc = -ENODATA;
 		goto fail_hypfs_sprp_exit;
 	}
-	s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
-	if (!s390_kobj) {
-		rc = -ENOMEM;
+	rc = sysfs_create_empty_dir(hypervisor_kobj, "s390");
+	if (rc)
 		goto fail_hypfs_diag0c_exit;
-	}
 	rc = register_filesystem(&hypfs_type);
 	if (rc)
 		goto fail_filesystem;
 	return 0;
 
 fail_filesystem:
-	kobject_put(s390_kobj);
+	sysfs_remove_empty_dir(hypervisor_kobj, "s390");
 fail_hypfs_diag0c_exit:
 	hypfs_diag0c_exit();
 fail_hypfs_sprp_exit:
@@ -510,7 +506,7 @@ fail_dbfs_exit:
 static void __exit hypfs_exit(void)
 {
 	unregister_filesystem(&hypfs_type);
-	kobject_put(s390_kobj);
+	sysfs_remove_empty_dir(hypervisor_kobj, "s390");
 	hypfs_diag0c_exit();
 	hypfs_sprp_exit();
 	hypfs_vm_exit();
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 3061bb8629dc..98523650efd9 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -65,7 +65,6 @@ static int __init parse_efi_cmdline(char *str)
 early_param("efi", parse_efi_cmdline);
 
 static struct kobject *efi_kobj;
-static struct kobject *efivars_kobj;
 
 /*
  * Let's not leave out systab information that snuck into
@@ -212,10 +211,9 @@ static int __init efisubsys_init(void)
 		goto err_remove_group;
 
 	/* and the standard mountpoint for efivarfs */
-	efivars_kobj = kobject_create_and_add("efivars", efi_kobj);
-	if (!efivars_kobj) {
+	error = sysfs_create_empty_dir(efi_kobj, "efivars");
+	if (error) {
 		pr_err("efivars: Subsystem registration failed.\n");
-		error = -ENOMEM;
 		goto err_remove_group;
 	}
 
diff --git a/fs/configfs/mount.c b/fs/configfs/mount.c
index da94e41bdbf6..b4d1580a6602 100644
--- a/fs/configfs/mount.c
+++ b/fs/configfs/mount.c
@@ -129,8 +129,6 @@ void configfs_release_fs(void)
 }
 
 
-static struct kobject *config_kobj;
-
 static int __init configfs_init(void)
 {
 	int err = -ENOMEM;
@@ -141,8 +139,8 @@ static int __init configfs_init(void)
 	if (!configfs_dir_cachep)
 		goto out;
 
-	config_kobj = kobject_create_and_add("config", kernel_kobj);
-	if (!config_kobj)
+	err = sysfs_create_empty_dir(kernel_kobj, "config");
+	if (err)
 		goto out2;
 
 	err = register_filesystem(&configfs_fs_type);
@@ -152,7 +150,7 @@ static int __init configfs_init(void)
 	return 0;
 out3:
 	pr_err("Unable to register filesystem!\n");
-	kobject_put(config_kobj);
+	sysfs_remove_empty_dir(kernel_kobj, "config");
 out2:
 	kmem_cache_destroy(configfs_dir_cachep);
 	configfs_dir_cachep = NULL;
@@ -163,7 +161,7 @@ out:
 static void __exit configfs_exit(void)
 {
 	unregister_filesystem(&configfs_fs_type);
-	kobject_put(config_kobj);
+	sysfs_remove_empty_dir(kernel_kobj, "config");
 	kmem_cache_destroy(configfs_dir_cachep);
 	configfs_dir_cachep = NULL;
 }
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index c1e7ffb0dab6..5bcb499980d0 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -716,20 +716,17 @@ bool debugfs_initialized(void)
 }
 EXPORT_SYMBOL_GPL(debugfs_initialized);
 
-
-static struct kobject *debug_kobj;
-
 static int __init debugfs_init(void)
 {
 	int retval;
 
-	debug_kobj = kobject_create_and_add("debug", kernel_kobj);
-	if (!debug_kobj)
-		return -EINVAL;
+	retval = sysfs_create_empty_dir(kernel_kobj, "debug");
+	if (retval)
+		return retval;
 
 	retval = register_filesystem(&debug_fs_type);
 	if (retval)
-		kobject_put(debug_kobj);
+		sysfs_remove_empty_dir(kernel_kobj, "debug");
 	else
 		debugfs_registered = true;
 
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 082ac1c97f39..475d9cfa59a9 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1238,7 +1238,6 @@ static void fuse_fs_cleanup(void)
 }
 
 static struct kobject *fuse_kobj;
-static struct kobject *connections_kobj;
 
 static int fuse_sysfs_init(void)
 {
@@ -1250,11 +1249,9 @@ static int fuse_sysfs_init(void)
 		goto out_err;
 	}
 
-	connections_kobj = kobject_create_and_add("connections", fuse_kobj);
-	if (!connections_kobj) {
-		err = -ENOMEM;
+	err = sysfs_create_empty_dir(fuse_kobj, "connections");
+	if (err)
 		goto out_fuse_unregister;
-	}
 
 	return 0;
 
@@ -1266,7 +1263,7 @@ static int fuse_sysfs_init(void)
 
 static void fuse_sysfs_cleanup(void)
 {
-	kobject_put(connections_kobj);
+	sysfs_remove_empty_dir(fuse_kobj, "connections");
 	kobject_put(fuse_kobj);
 }
 
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index dc43b5f29305..d1caeefd2d1b 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -461,22 +461,18 @@ static struct file_system_type pstore_fs_type = {
 	.kill_sb	= pstore_kill_sb,
 };
 
-static struct kobject *pstore_kobj;
-
 static int __init init_pstore_fs(void)
 {
-	int err = 0;
+	int err;
 
 	/* Create a convenient mount point for people to access pstore */
-	pstore_kobj = kobject_create_and_add("pstore", fs_kobj);
-	if (!pstore_kobj) {
-		err = -ENOMEM;
+	err = sysfs_create_empty_dir(fs_kobj, "pstore");
+	if (err)
 		goto out;
-	}
 
 	err = register_filesystem(&pstore_fs_type);
 	if (err < 0)
-		kobject_put(pstore_kobj);
+		sysfs_remove_empty_dir(fs_kobj, "pstore");
 
 out:
 	return err;
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index d92bdf3b079a..e887c881a4b3 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -631,14 +631,12 @@ bool tracefs_initialized(void)
 	return tracefs_registered;
 }
 
-static struct kobject *trace_kobj;
-
 static int __init tracefs_init(void)
 {
 	int retval;
 
-	trace_kobj = kobject_create_and_add("tracing", kernel_kobj);
-	if (!trace_kobj)
+	retval = sysfs_create_empty_dir(kernel_kobj, "tracing");
+	if (retval)
 		return -EINVAL;
 
 	retval = register_filesystem(&trace_fs_type);
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 469dd547770c..816657b5ef16 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1924,8 +1924,6 @@ static struct file_system_type cgroup_fs_type = {
 	.kill_sb = cgroup_kill_sb,
 };
 
-static struct kobject *cgroup_kobj;
-
 /**
  * task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
  * @task: target task
@@ -5044,13 +5042,13 @@ int __init cgroup_init(void)
 			ss->bind(init_css_set.subsys[ssid]);
 	}
 
-	cgroup_kobj = kobject_create_and_add("cgroup", fs_kobj);
-	if (!cgroup_kobj)
-		return -ENOMEM;
+	err = sysfs_create_empty_dir(fs_kobj, "cgroup");
+	if (err)
+		return err;
 
 	err = register_filesystem(&cgroup_fs_type);
 	if (err < 0) {
-		kobject_put(cgroup_kobj);
+		sysfs_remove_empty_dir(fs_kobj, "cgroup");
 		return err;
 	}
 
diff --git a/security/inode.c b/security/inode.c
index 91503b79c5f8..d7e5de5ffc59 100644
--- a/security/inode.c
+++ b/security/inode.c
@@ -215,19 +215,17 @@ void securityfs_remove(struct dentry *dentry)
 }
 EXPORT_SYMBOL_GPL(securityfs_remove);
 
-static struct kobject *security_kobj;
-
 static int __init securityfs_init(void)
 {
 	int retval;
 
-	security_kobj = kobject_create_and_add("security", kernel_kobj);
-	if (!security_kobj)
-		return -EINVAL;
+	retval = sysfs_create_empty_dir(kernel_kobj, "security");
+	if (retval)
+		return retval;
 
 	retval = register_filesystem(&fs_type);
 	if (retval)
-		kobject_put(security_kobj);
+		sysfs_remove_empty_dir(kernel_kobj, "security");
 	return retval;
 }
 
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index d2787cca1fcb..a3d882729a45 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -1853,7 +1853,6 @@ static struct file_system_type sel_fs_type = {
 };
 
 struct vfsmount *selinuxfs_mount;
-static struct kobject *selinuxfs_kobj;
 
 static int __init init_sel_fs(void)
 {
@@ -1862,13 +1861,13 @@ static int __init init_sel_fs(void)
 	if (!selinux_enabled)
 		return 0;
 
-	selinuxfs_kobj = kobject_create_and_add("selinux", fs_kobj);
-	if (!selinuxfs_kobj)
-		return -ENOMEM;
+	err = sysfs_create_empty_dir(fs_kobj, "selinux");
+	if (err)
+		return err;
 
 	err = register_filesystem(&sel_fs_type);
 	if (err) {
-		kobject_put(selinuxfs_kobj);
+		sysfs_remove_empty_dir(fs_kobj, "selinux");
 		return err;
 	}
 
@@ -1887,7 +1886,7 @@ __initcall(init_sel_fs);
 #ifdef CONFIG_SECURITY_SELINUX_DISABLE
 void exit_sel_fs(void)
 {
-	kobject_put(selinuxfs_kobj);
+	sysfs_remove_empty_dir(fs_kobj, "selinux");
 	kern_unmount(selinuxfs_mount);
 	unregister_filesystem(&sel_fs_type);
 }
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index d9682985349e..35079cc8c765 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -2241,16 +2241,16 @@ static const struct file_operations smk_revoke_subj_ops = {
 	.llseek		= generic_file_llseek,
 };
 
-static struct kset *smackfs_kset;
 /**
  * smk_init_sysfs - initialize /sys/fs/smackfs
  *
  */
 static int smk_init_sysfs(void)
 {
-	smackfs_kset = kset_create_and_add("smackfs", NULL, fs_kobj);
-	if (!smackfs_kset)
-		return -ENOMEM;
+	int err;
+	err = sysfs_create_empty_dir(fs_kobj, "smackfs");
+	if (err)
+		return err;
 	return 0;
 }
 
-- 
2.2.1