From 37c1c04cca920de8a68285751b2c7b3d937ad50c Mon Sep 17 00:00:00 2001 From: Jarkko Sakkinen Date: Wed, 22 Apr 2015 19:36:06 +0300 Subject: [PATCH] sysfs: added __compat_only_sysfs_link_entry_to_kobj() Added a new function __compat_only_sysfs_link_group_to_kobj() that adds a symlink from attribute or group to a kobject. This needed for maintaining backwards compatibility with PPI attributes in the TPM driver. Signed-off-by: Jarkko Sakkinen Signed-off-by: Peter Huewe --- fs/sysfs/group.c | 44 +++++++++++++++++++++++++++++++++++++++++++ include/linux/sysfs.h | 11 +++++++++++ 2 files changed, 55 insertions(+) diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c index 39a019936768..e1236594fffe 100644 --- a/fs/sysfs/group.c +++ b/fs/sysfs/group.c @@ -352,3 +352,47 @@ void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name, } } EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group); + +/** + * __compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing + * to a group or an attribute + * @kobj: The kobject containing the group. + * @target_kobj: The target kobject. + * @target_name: The name of the target group or attribute. + */ +int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj, + struct kobject *target_kobj, + const char *target_name) +{ + struct kernfs_node *target; + struct kernfs_node *entry; + struct kernfs_node *link; + + /* + * We don't own @target_kobj and it may be removed at any time. + * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir() + * for details. + */ + spin_lock(&sysfs_symlink_target_lock); + target = target_kobj->sd; + if (target) + kernfs_get(target); + spin_unlock(&sysfs_symlink_target_lock); + if (!target) + return -ENOENT; + + entry = kernfs_find_and_get(target_kobj->sd, target_name); + if (!entry) { + kernfs_put(target); + return -ENOENT; + } + + link = kernfs_create_link(kobj->sd, target_name, entry); + if (IS_ERR(link) && PTR_ERR(link) == -EEXIST) + sysfs_warn_dup(kobj->sd, target_name); + + kernfs_put(entry); + kernfs_put(target); + return IS_ERR(link) ? PTR_ERR(link) : 0; +} +EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj); diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index 9f65758311a4..ea090eaf468c 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -268,6 +268,9 @@ int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name, struct kobject *target, const char *link_name); void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name, const char *link_name); +int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj, + struct kobject *target_kobj, + const char *target_name); void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr); @@ -451,6 +454,14 @@ static inline void sysfs_remove_link_from_group(struct kobject *kobj, { } +static inline int __compat_only_sysfs_link_entry_to_kobj( + struct kobject *kobj, + struct kobject *target_kobj, + const char *target_name) +{ + return 0; +} + static inline void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr) { -- 2.20.1