diff options
Diffstat (limited to 'fs/sysfs')
| -rw-r--r-- | fs/sysfs/file.c | 4 | ||||
| -rw-r--r-- | fs/sysfs/group.c | 44 |
2 files changed, 47 insertions, 1 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 6c95628ea377..f35523d4fa3a 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -108,6 +108,7 @@ static ssize_t sysfs_kf_read(struct kernfs_open_file *of, char *buf, { const struct sysfs_ops *ops = sysfs_file_ops(of->kn); struct kobject *kobj = of->kn->parent->priv; + size_t len; /* * If buf != of->prealloc_buf, we don't know how @@ -115,7 +116,8 @@ static ssize_t sysfs_kf_read(struct kernfs_open_file *of, char *buf, */ if (pos || WARN_ON_ONCE(buf != of->prealloc_buf)) return 0; - return ops->show(kobj, of->kn->priv, buf); + len = ops->show(kobj, of->kn->priv, buf); + return min(count, len); } /* kernfs write callback for regular sysfs files */ diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c index 51b56e6d9537..dc1358b5ec95 100644 --- a/fs/sysfs/group.c +++ b/fs/sysfs/group.c @@ -365,3 +365,47 @@ 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); |