sysfs, kernfs: revamp sysfs_dirent active_ref lockdep annotation
Currently, sysfs_dirent active_ref lockdep annotation uses attribute->[s]key as the lockdep key, which forces kernfs_create_file_ns() to assume that sysfs_dirent->priv is pointing to a struct attribute which may not be true for non-sysfs users. This patch restructures the lockdep annotation such that * kernfs_ops contains lockdep_key which is used by default for files created kernfs_create_file_ns(). * kernfs_create_file_ns_key() is introduced which takes an extra @key argument. The created file will use the specified key for active_ref lockdep annotation. If NULL is specified, lockdep for the file is disabled. * sysfs_add_file_mode_ns() is updated to use kernfs_create_file_ns_key() with the appropriate key from the attribute or NULL if ignore_lockdep is set. This makes the lockdep annotation properly contained in kernfs while allowing sysfs to cleanly keep its current behavior. This patch doesn't introduce any behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tejun Heo
Greg Kroah-Hartman
parent
2b25a62901
commit
517e64f578
@ -150,7 +150,7 @@ struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
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if (!atomic_inc_unless_negative(&sd->s_active))
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return NULL;
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if (likely(!sysfs_ignore_lockdep(sd)))
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if (sd->s_flags & SYSFS_FLAG_LOCKDEP)
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rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
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return sd;
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}
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@ -169,7 +169,7 @@ void sysfs_put_active(struct sysfs_dirent *sd)
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if (unlikely(!sd))
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return;
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if (likely(!sysfs_ignore_lockdep(sd)))
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if (sd->s_flags & SYSFS_FLAG_LOCKDEP)
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rwsem_release(&sd->dep_map, 1, _RET_IP_);
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v = atomic_dec_return(&sd->s_active);
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if (likely(v != SD_DEACTIVATED_BIAS))
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@ -58,7 +58,7 @@ static struct sysfs_open_file *sysfs_of(struct file *file)
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*/
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static const struct kernfs_ops *kernfs_ops(struct sysfs_dirent *sd)
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{
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if (!sysfs_ignore_lockdep(sd))
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if (sd->s_flags & SYSFS_FLAG_LOCKDEP)
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lockdep_assert_held(sd);
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return sd->s_attr.ops;
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}
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@ -71,7 +71,7 @@ static const struct sysfs_ops *sysfs_file_ops(struct sysfs_dirent *sd)
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{
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struct kobject *kobj = sd->s_parent->priv;
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if (!sysfs_ignore_lockdep(sd))
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if (sd->s_flags & SYSFS_FLAG_LOCKDEP)
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lockdep_assert_held(sd);
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return kobj->ktype ? kobj->ktype->sysfs_ops : NULL;
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}
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@ -942,6 +942,7 @@ int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,
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const struct attribute *attr, bool is_bin,
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umode_t mode, const void *ns)
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{
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struct lock_class_key *key = NULL;
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const struct kernfs_ops *ops;
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struct sysfs_dirent *sd;
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loff_t size;
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@ -981,8 +982,12 @@ int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,
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size = battr->size;
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}
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sd = kernfs_create_file_ns(dir_sd, attr->name, mode, size,
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ops, (void *)attr, ns);
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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if (!attr->ignore_lockdep)
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key = attr->key ?: (struct lock_class_key *)&attr->skey;
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#endif
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sd = kernfs_create_file_ns_key(dir_sd, attr->name, mode, size,
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ops, (void *)attr, ns, key);
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if (IS_ERR(sd)) {
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if (PTR_ERR(sd) == -EEXIST)
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sysfs_warn_dup(dir_sd, attr->name);
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@ -992,7 +997,7 @@ int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,
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}
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/**
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* kernfs_create_file_ns - create a file
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* kernfs_create_file_ns_key - create a file
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* @parent: directory to create the file in
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* @name: name of the file
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* @mode: mode of the file
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@ -1000,14 +1005,16 @@ int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,
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* @ops: kernfs operations for the file
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* @priv: private data for the file
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* @ns: optional namespace tag of the file
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* @key: lockdep key for the file's active_ref, %NULL to disable lockdep
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*
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* Returns the created node on success, ERR_PTR() value on error.
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*/
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struct sysfs_dirent *kernfs_create_file_ns(struct sysfs_dirent *parent,
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const char *name,
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umode_t mode, loff_t size,
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const struct kernfs_ops *ops,
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void *priv, const void *ns)
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struct sysfs_dirent *kernfs_create_file_ns_key(struct sysfs_dirent *parent,
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const char *name,
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umode_t mode, loff_t size,
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const struct kernfs_ops *ops,
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void *priv, const void *ns,
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struct lock_class_key *key)
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{
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struct sysfs_addrm_cxt acxt;
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struct sysfs_dirent *sd;
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@ -1022,7 +1029,13 @@ struct sysfs_dirent *kernfs_create_file_ns(struct sysfs_dirent *parent,
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sd->s_attr.size = size;
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sd->s_ns = ns;
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sd->priv = priv;
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sysfs_dirent_init_lockdep(sd);
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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if (key) {
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lockdep_init_map(&sd->dep_map, "s_active", key, 0);
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sd->s_flags |= SYSFS_FLAG_LOCKDEP;
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}
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#endif
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/*
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* sd->s_attr.ops is accesible only while holding active ref. We
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@ -92,43 +92,13 @@ struct sysfs_dirent {
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#define SYSFS_FLAG_NS 0x0020
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#define SYSFS_FLAG_HAS_SEQ_SHOW 0x0040
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#define SYSFS_FLAG_HAS_MMAP 0x0080
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#define SYSFS_FLAG_LOCKDEP 0x0100
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static inline unsigned int sysfs_type(struct sysfs_dirent *sd)
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{
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return sd->s_flags & SYSFS_TYPE_MASK;
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}
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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#define sysfs_dirent_init_lockdep(sd) \
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do { \
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struct attribute *attr = sd->priv; \
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struct lock_class_key *key = attr->key; \
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if (!key) \
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key = &attr->skey; \
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\
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lockdep_init_map(&sd->dep_map, "s_active", key, 0); \
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} while (0)
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/* Test for attributes that want to ignore lockdep for read-locking */
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static inline bool sysfs_ignore_lockdep(struct sysfs_dirent *sd)
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{
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struct attribute *attr = sd->priv;
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return sysfs_type(sd) == SYSFS_KOBJ_ATTR && attr->ignore_lockdep;
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}
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#else
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#define sysfs_dirent_init_lockdep(sd) do {} while (0)
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static inline bool sysfs_ignore_lockdep(struct sysfs_dirent *sd)
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{
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return true;
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}
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#endif
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/*
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* Context structure to be used while adding/removing nodes.
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*/
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@ -11,6 +11,7 @@
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#include <linux/err.h>
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#include <linux/list.h>
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#include <linux/mutex.h>
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#include <linux/lockdep.h>
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struct file;
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struct iattr;
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@ -62,6 +63,10 @@ struct kernfs_ops {
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loff_t off);
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int (*mmap)(struct sysfs_open_file *of, struct vm_area_struct *vma);
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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struct lock_class_key lockdep_key;
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#endif
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};
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#ifdef CONFIG_SYSFS
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@ -69,11 +74,12 @@ struct kernfs_ops {
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struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent,
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const char *name, void *priv,
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const void *ns);
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struct sysfs_dirent *kernfs_create_file_ns(struct sysfs_dirent *parent,
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const char *name,
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umode_t mode, loff_t size,
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const struct kernfs_ops *ops,
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void *priv, const void *ns);
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struct sysfs_dirent *kernfs_create_file_ns_key(struct sysfs_dirent *parent,
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const char *name,
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umode_t mode, loff_t size,
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const struct kernfs_ops *ops,
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void *priv, const void *ns,
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struct lock_class_key *key);
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struct sysfs_dirent *kernfs_create_link(struct sysfs_dirent *parent,
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const char *name,
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struct sysfs_dirent *target);
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@ -94,9 +100,10 @@ kernfs_create_dir_ns(struct sysfs_dirent *parent, const char *name, void *priv,
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{ return ERR_PTR(-ENOSYS); }
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static inline struct sysfs_dirent *
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kernfs_create_file_ns(struct sysfs_dirent *parent, const char *name,
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umode_t mode, loff_t size, const struct kernfs_ops *ops,
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void *priv, const void *ns)
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kernfs_create_file_ns_key(struct sysfs_dirent *parent, const char *name,
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umode_t mode, loff_t size,
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const struct kernfs_ops *ops, void *priv,
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const void *ns, struct lock_class_key *key)
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{ return ERR_PTR(-ENOSYS); }
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static inline struct sysfs_dirent *
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@ -131,6 +138,20 @@ kernfs_create_dir(struct sysfs_dirent *parent, const char *name, void *priv)
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return kernfs_create_dir_ns(parent, name, priv, NULL);
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}
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static inline struct sysfs_dirent *
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kernfs_create_file_ns(struct sysfs_dirent *parent, const char *name,
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umode_t mode, loff_t size, const struct kernfs_ops *ops,
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void *priv, const void *ns)
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{
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struct lock_class_key *key = NULL;
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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key = (struct lock_class_key *)&ops->lockdep_key;
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#endif
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return kernfs_create_file_ns_key(parent, name, mode, size, ops, priv,
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ns, key);
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}
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static inline struct sysfs_dirent *
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kernfs_create_file(struct sysfs_dirent *parent, const char *name, umode_t mode,
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loff_t size, const struct kernfs_ops *ops, void *priv)
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