include/linux/kernfs.h - kernel/msm-4.19 - Gitiles

 /*
  * kernfs.h - pseudo filesystem decoupled from vfs locking
  *
  * This file is released under the GPLv2.
  */

 #ifndef __LINUX_KERNFS_H
 #define __LINUX_KERNFS_H

 #include <linux/kernel.h>
 #include <linux/err.h>
 #include <linux/list.h>
 #include <linux/mutex.h>
 #include <linux/idr.h>
 #include <linux/lockdep.h>
 #include <linux/rbtree.h>
 #include <linux/atomic.h>
 #include <linux/completion.h>

 struct file;
 struct iattr;
 struct seq_file;
 struct vm_area_struct;
 struct super_block;
 struct file_system_type;

 struct sysfs_open_dirent;
 struct sysfs_inode_attrs;

 enum kernfs_node_type {
 	SYSFS_DIR		= 0x0001,
 	SYSFS_KOBJ_ATTR		= 0x0002,
 	SYSFS_KOBJ_LINK		= 0x0004,
 };

 #define SYSFS_TYPE_MASK		0x000f
 #define SYSFS_COPY_NAME		(SYSFS_DIR | SYSFS_KOBJ_LINK)
 #define SYSFS_ACTIVE_REF	SYSFS_KOBJ_ATTR
 #define SYSFS_FLAG_MASK		~SYSFS_TYPE_MASK

 enum kernfs_node_flag {
 	SYSFS_FLAG_REMOVED	= 0x0010,
 	SYSFS_FLAG_NS		= 0x0020,
 	SYSFS_FLAG_HAS_SEQ_SHOW	= 0x0040,
 	SYSFS_FLAG_HAS_MMAP	= 0x0080,
 	SYSFS_FLAG_LOCKDEP	= 0x0100,
 };

 /* type-specific structures for kernfs_node union members */
 struct kernfs_elem_dir {
 	unsigned long		subdirs;
 	/* children rbtree starts here and goes through kn->rb */
 	struct rb_root		children;

 	/*
 	 * The kernfs hierarchy this directory belongs to.  This fits
 	 * better directly in kernfs_node but is here to save space.
 	 */
 	struct kernfs_root	*root;
 };

 struct kernfs_elem_symlink {
 	struct kernfs_node	*target_kn;
 };

 struct kernfs_elem_attr {
 	const struct kernfs_ops	*ops;
 	struct sysfs_open_dirent *open;
 	loff_t			size;
 };

 /*
  * kernfs_node - the building block of kernfs hierarchy.  Each and every
  * kernfs node is represented by single kernfs_node.  Most fields are
  * private to kernfs and shouldn't be accessed directly by kernfs users.
  *
  * As long as s_count reference is held, the kernfs_node itself is
  * accessible.  Dereferencing elem or any other outer entity requires
  * active reference.
  */
 struct kernfs_node {
 	atomic_t		count;
 	atomic_t		active;
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map	dep_map;
 #endif
 	/* the following two fields are published */
 	struct kernfs_node	*parent;
 	const char		*name;

 	struct rb_node		rb;

 	union {
 		struct completion	*completion;
 		struct kernfs_node	*removed_list;
 	} u;

 	const void		*ns;	/* namespace tag */
 	unsigned int		hash;	/* ns + name hash */
 	union {
 		struct kernfs_elem_dir		dir;
 		struct kernfs_elem_symlink	symlink;
 		struct kernfs_elem_attr		attr;
 	};

 	void			*priv;

 	unsigned short		flags;
 	umode_t			mode;
 	unsigned int		ino;
 	struct sysfs_inode_attrs *iattr;
 };

 struct kernfs_root {
 	/* published fields */
 	struct kernfs_node	*kn;

 	/* private fields, do not use outside kernfs proper */
 	struct ida		ino_ida;
 };

 struct sysfs_open_file {
 	/* published fields */
 	struct kernfs_node	*kn;
 	struct file		*file;

 	/* private fields, do not use outside kernfs proper */
 	struct mutex		mutex;
 	int			event;
 	struct list_head	list;

 	bool			mmapped;
 	const struct vm_operations_struct *vm_ops;
 };

 struct kernfs_ops {
 	/*
 	 * Read is handled by either seq_file or raw_read().
 	 *
 	 * If seq_show() is present, seq_file path is active.  Other seq
 	 * operations are optional and if not implemented, the behavior is
 	 * equivalent to single_open().  @sf->private points to the
 	 * associated sysfs_open_file.
 	 *
 	 * read() is bounced through kernel buffer and a read larger than
 	 * PAGE_SIZE results in partial operation of PAGE_SIZE.
 	 */
 	int (*seq_show)(struct seq_file *sf, void *v);

 	void *(*seq_start)(struct seq_file *sf, loff_t *ppos);
 	void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos);
 	void (*seq_stop)(struct seq_file *sf, void *v);

 	ssize_t (*read)(struct sysfs_open_file *of, char *buf, size_t bytes,
 			loff_t off);

 	/*
 	 * write() is bounced through kernel buffer and a write larger than
 	 * PAGE_SIZE results in partial operation of PAGE_SIZE.
 	 */
 	ssize_t (*write)(struct sysfs_open_file *of, char *buf, size_t bytes,
 			 loff_t off);

 	int (*mmap)(struct sysfs_open_file *of, struct vm_area_struct *vma);

 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lock_class_key	lockdep_key;
 #endif
 };

 #ifdef CONFIG_SYSFS

 static inline enum kernfs_node_type sysfs_type(struct kernfs_node *kn)
 {
 	return kn->flags & SYSFS_TYPE_MASK;
 }

 /**
  * kernfs_enable_ns - enable namespace under a directory
  * @kn: directory of interest, should be empty
  *
  * This is to be called right after @kn is created to enable namespace
  * under it.  All children of @kn must have non-NULL namespace tags and
  * only the ones which match the super_block's tag will be visible.
  */
 static inline void kernfs_enable_ns(struct kernfs_node *kn)
 {
 	WARN_ON_ONCE(sysfs_type(kn) != SYSFS_DIR);
 	WARN_ON_ONCE(!RB_EMPTY_ROOT(&kn->dir.children));
 	kn->flags |= SYSFS_FLAG_NS;
 }

 /**
  * kernfs_ns_enabled - test whether namespace is enabled
  * @kn: the node to test
  *
  * Test whether namespace filtering is enabled for the children of @ns.
  */
 static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
 {
 	return kn->flags & SYSFS_FLAG_NS;
 }

 struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
 					   const char *name, const void *ns);
 void kernfs_get(struct kernfs_node *kn);
 void kernfs_put(struct kernfs_node *kn);

 struct kernfs_root *kernfs_create_root(void *priv);
 void kernfs_destroy_root(struct kernfs_root *root);

 struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
 					 const char *name, void *priv,
 					 const void *ns);
 struct kernfs_node *kernfs_create_file_ns_key(struct kernfs_node *parent,
 					      const char *name,
 					      umode_t mode, loff_t size,
 					      const struct kernfs_ops *ops,
 					      void *priv, const void *ns,
 					      struct lock_class_key *key);
 struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
 				       const char *name,
 				       struct kernfs_node *target);
 void kernfs_remove(struct kernfs_node *kn);
 int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
 			     const void *ns);
 int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
 		     const char *new_name, const void *new_ns);
 int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr);
 void kernfs_notify(struct kernfs_node *kn);

 const void *kernfs_super_ns(struct super_block *sb);
 struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
 			       struct kernfs_root *root, const void *ns);
 void kernfs_kill_sb(struct super_block *sb);

 void kernfs_init(void);

 #else	/* CONFIG_SYSFS */

 static inline enum kernfs_node_type sysfs_type(struct kernfs_node *kn)
 { return 0; }	/* whatever */

 static inline void kernfs_enable_ns(struct kernfs_node *kn) { }

 static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
 { return false; }

 static inline struct kernfs_node *
 kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name,
 		       const void *ns)
 { return NULL; }

 static inline void kernfs_get(struct kernfs_node *kn) { }
 static inline void kernfs_put(struct kernfs_node *kn) { }

 static inline struct kernfs_root *kernfs_create_root(void *priv)
 { return ERR_PTR(-ENOSYS); }

 static inline void kernfs_destroy_root(struct kernfs_root *root) { }

 static inline struct kernfs_node *
 kernfs_create_dir_ns(struct kernfs_node *parent, const char *name, void *priv,
 		     const void *ns)
 { return ERR_PTR(-ENOSYS); }

 static inline struct kernfs_node *
 kernfs_create_file_ns_key(struct kernfs_node *parent, const char *name,
 			  umode_t mode, loff_t size,
 			  const struct kernfs_ops *ops, void *priv,
 			  const void *ns, struct lock_class_key *key)
 { return ERR_PTR(-ENOSYS); }

 static inline struct kernfs_node *
 kernfs_create_link(struct kernfs_node *parent, const char *name,
 		   struct kernfs_node *target)
 { return ERR_PTR(-ENOSYS); }

 static inline void kernfs_remove(struct kernfs_node *kn) { }

 static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn,
 					   const char *name, const void *ns)
 { return -ENOSYS; }

 static inline int kernfs_rename_ns(struct kernfs_node *kn,
 				   struct kernfs_node *new_parent,
 				   const char *new_name, const void *new_ns)
 { return -ENOSYS; }

 static inline int kernfs_setattr(struct kernfs_node *kn,
 				 const struct iattr *iattr)
 { return -ENOSYS; }

 static inline void kernfs_notify(struct kernfs_node *kn) { }

 static inline const void *kernfs_super_ns(struct super_block *sb)
 { return NULL; }

 static inline struct dentry *
 kernfs_mount_ns(struct file_system_type *fs_type, int flags,
 		struct kernfs_root *root, const void *ns)
 { return ERR_PTR(-ENOSYS); }

 static inline void kernfs_kill_sb(struct super_block *sb) { }

 static inline void kernfs_init(void) { }

 #endif	/* CONFIG_SYSFS */

 static inline struct kernfs_node *
 kernfs_find_and_get(struct kernfs_node *kn, const char *name)
 {
 	return kernfs_find_and_get_ns(kn, name, NULL);
 }

 static inline struct kernfs_node *
 kernfs_create_dir(struct kernfs_node *parent, const char *name, void *priv)
 {
 	return kernfs_create_dir_ns(parent, name, priv, NULL);
 }

 static inline struct kernfs_node *
 kernfs_create_file_ns(struct kernfs_node *parent, const char *name,
 		      umode_t mode, loff_t size, const struct kernfs_ops *ops,
 		      void *priv, const void *ns)
 {
 	struct lock_class_key *key = NULL;

 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	key = (struct lock_class_key *)&ops->lockdep_key;
 #endif
 	return kernfs_create_file_ns_key(parent, name, mode, size, ops, priv,
 					 ns, key);
 }

 static inline struct kernfs_node *
 kernfs_create_file(struct kernfs_node *parent, const char *name, umode_t mode,
 		   loff_t size, const struct kernfs_ops *ops, void *priv)
 {
 	return kernfs_create_file_ns(parent, name, mode, size, ops, priv, NULL);
 }

 static inline int kernfs_remove_by_name(struct kernfs_node *parent,
 					const char *name)
 {
 	return kernfs_remove_by_name_ns(parent, name, NULL);
 }

 static inline struct dentry *
 kernfs_mount(struct file_system_type *fs_type, int flags,
 	     struct kernfs_root *root)
 {
 	return kernfs_mount_ns(fs_type, flags, root, NULL);
 }

 #endif	/* __LINUX_KERNFS_H */
	/*
	* kernfs.h - pseudo filesystem decoupled from vfs locking
	*
	* This file is released under the GPLv2.
	*/

	#ifndef __LINUX_KERNFS_H
	#define __LINUX_KERNFS_H

	#include <linux/kernel.h>
	#include <linux/err.h>
	#include <linux/list.h>
	#include <linux/mutex.h>
	#include <linux/idr.h>
	#include <linux/lockdep.h>
	#include <linux/rbtree.h>
	#include <linux/atomic.h>
	#include <linux/completion.h>

	struct file;
	struct iattr;
	struct seq_file;
	struct vm_area_struct;
	struct super_block;
	struct file_system_type;

	struct sysfs_open_dirent;
	struct sysfs_inode_attrs;

	enum kernfs_node_type {
	SYSFS_DIR = 0x0001,
	SYSFS_KOBJ_ATTR = 0x0002,
	SYSFS_KOBJ_LINK = 0x0004,
	};

	#define SYSFS_TYPE_MASK 0x000f
	#define SYSFS_COPY_NAME (SYSFS_DIR \| SYSFS_KOBJ_LINK)
	#define SYSFS_ACTIVE_REF SYSFS_KOBJ_ATTR
	#define SYSFS_FLAG_MASK ~SYSFS_TYPE_MASK

	enum kernfs_node_flag {
	SYSFS_FLAG_REMOVED = 0x0010,
	SYSFS_FLAG_NS = 0x0020,
	SYSFS_FLAG_HAS_SEQ_SHOW = 0x0040,
	SYSFS_FLAG_HAS_MMAP = 0x0080,
	SYSFS_FLAG_LOCKDEP = 0x0100,
	};

	/* type-specific structures for kernfs_node union members */
	struct kernfs_elem_dir {
	unsigned long subdirs;
	/* children rbtree starts here and goes through kn->rb */
	struct rb_root children;

	/*
	* The kernfs hierarchy this directory belongs to. This fits
	* better directly in kernfs_node but is here to save space.
	*/
	struct kernfs_root *root;
	};

	struct kernfs_elem_symlink {
	struct kernfs_node *target_kn;
	};

	struct kernfs_elem_attr {
	const struct kernfs_ops *ops;
	struct sysfs_open_dirent *open;
	loff_t size;
	};

	/*
	* kernfs_node - the building block of kernfs hierarchy. Each and every
	* kernfs node is represented by single kernfs_node. Most fields are
	* private to kernfs and shouldn't be accessed directly by kernfs users.
	*
	* As long as s_count reference is held, the kernfs_node itself is
	* accessible. Dereferencing elem or any other outer entity requires
	* active reference.
	*/
	struct kernfs_node {
	atomic_t count;
	atomic_t active;
	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	struct lockdep_map dep_map;
	#endif
	/* the following two fields are published */
	struct kernfs_node *parent;
	const char *name;

	struct rb_node rb;

	union {
	struct completion *completion;
	struct kernfs_node *removed_list;
	} u;

	const void ns; / namespace tag */
	unsigned int hash; /* ns + name hash */
	union {
	struct kernfs_elem_dir dir;
	struct kernfs_elem_symlink symlink;
	struct kernfs_elem_attr attr;
	};

	void *priv;

	unsigned short flags;
	umode_t mode;
	unsigned int ino;
	struct sysfs_inode_attrs *iattr;
	};

	struct kernfs_root {
	/* published fields */
	struct kernfs_node *kn;

	/* private fields, do not use outside kernfs proper */
	struct ida ino_ida;
	};

	struct sysfs_open_file {
	/* published fields */
	struct kernfs_node *kn;
	struct file *file;

	/* private fields, do not use outside kernfs proper */
	struct mutex mutex;
	int event;
	struct list_head list;

	bool mmapped;
	const struct vm_operations_struct *vm_ops;
	};

	struct kernfs_ops {
	/*
	* Read is handled by either seq_file or raw_read().
	*
	* If seq_show() is present, seq_file path is active. Other seq
	* operations are optional and if not implemented, the behavior is
	* equivalent to single_open(). @sf->private points to the
	* associated sysfs_open_file.
	*
	* read() is bounced through kernel buffer and a read larger than
	* PAGE_SIZE results in partial operation of PAGE_SIZE.
	*/
	int (seq_show)(struct seq_file sf, void *v);

	void (seq_start)(struct seq_file sf, loff_t ppos);
	void (seq_next)(struct seq_file sf, void v, loff_t *ppos);
	void (seq_stop)(struct seq_file sf, void *v);

	ssize_t (read)(struct sysfs_open_file of, char *buf, size_t bytes,
	loff_t off);

	/*
	* write() is bounced through kernel buffer and a write larger than
	* PAGE_SIZE results in partial operation of PAGE_SIZE.
	*/
	ssize_t (write)(struct sysfs_open_file of, char *buf, size_t bytes,
	loff_t off);

	int (mmap)(struct sysfs_open_file of, struct vm_area_struct *vma);

	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	struct lock_class_key lockdep_key;
	#endif
	};

	#ifdef CONFIG_SYSFS

	static inline enum kernfs_node_type sysfs_type(struct kernfs_node *kn)
	{
	return kn->flags & SYSFS_TYPE_MASK;
	}

	/**
	* kernfs_enable_ns - enable namespace under a directory
	* @kn: directory of interest, should be empty
	*
	* This is to be called right after @kn is created to enable namespace
	* under it. All children of @kn must have non-NULL namespace tags and
	* only the ones which match the super_block's tag will be visible.
	*/
	static inline void kernfs_enable_ns(struct kernfs_node *kn)
	{
	WARN_ON_ONCE(sysfs_type(kn) != SYSFS_DIR);
	WARN_ON_ONCE(!RB_EMPTY_ROOT(&kn->dir.children));
	kn->flags \|= SYSFS_FLAG_NS;
	}

	/**
	* kernfs_ns_enabled - test whether namespace is enabled
	* @kn: the node to test
	*
	* Test whether namespace filtering is enabled for the children of @ns.
	*/
	static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
	{
	return kn->flags & SYSFS_FLAG_NS;
	}

	struct kernfs_node kernfs_find_and_get_ns(struct kernfs_node parent,
	const char name, const void ns);
	void kernfs_get(struct kernfs_node *kn);
	void kernfs_put(struct kernfs_node *kn);

	struct kernfs_root kernfs_create_root(void priv);
	void kernfs_destroy_root(struct kernfs_root *root);

	struct kernfs_node kernfs_create_dir_ns(struct kernfs_node parent,
	const char name, void priv,
	const void *ns);
	struct kernfs_node kernfs_create_file_ns_key(struct kernfs_node parent,
	const char *name,
	umode_t mode, loff_t size,
	const struct kernfs_ops *ops,
	void priv, const void ns,
	struct lock_class_key *key);
	struct kernfs_node kernfs_create_link(struct kernfs_node parent,
	const char *name,
	struct kernfs_node *target);
	void kernfs_remove(struct kernfs_node *kn);
	int kernfs_remove_by_name_ns(struct kernfs_node parent, const char name,
	const void *ns);
	int kernfs_rename_ns(struct kernfs_node kn, struct kernfs_node new_parent,
	const char new_name, const void new_ns);
	int kernfs_setattr(struct kernfs_node kn, const struct iattr iattr);
	void kernfs_notify(struct kernfs_node *kn);

	const void kernfs_super_ns(struct super_block sb);
	struct dentry kernfs_mount_ns(struct file_system_type fs_type, int flags,
	struct kernfs_root root, const void ns);
	void kernfs_kill_sb(struct super_block *sb);

	void kernfs_init(void);

	#else /* CONFIG_SYSFS */

	static inline enum kernfs_node_type sysfs_type(struct kernfs_node *kn)
	{ return 0; } /* whatever */

	static inline void kernfs_enable_ns(struct kernfs_node *kn) { }

	static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
	{ return false; }

	static inline struct kernfs_node *
	kernfs_find_and_get_ns(struct kernfs_node parent, const char name,
	const void *ns)
	{ return NULL; }

	static inline void kernfs_get(struct kernfs_node *kn) { }
	static inline void kernfs_put(struct kernfs_node *kn) { }

	static inline struct kernfs_root kernfs_create_root(void priv)
	{ return ERR_PTR(-ENOSYS); }

	static inline void kernfs_destroy_root(struct kernfs_root *root) { }

	static inline struct kernfs_node *
	kernfs_create_dir_ns(struct kernfs_node parent, const char name, void *priv,
	const void *ns)
	{ return ERR_PTR(-ENOSYS); }

	static inline struct kernfs_node *
	kernfs_create_file_ns_key(struct kernfs_node parent, const char name,
	umode_t mode, loff_t size,
	const struct kernfs_ops ops, void priv,
	const void ns, struct lock_class_key key)
	{ return ERR_PTR(-ENOSYS); }

	static inline struct kernfs_node *
	kernfs_create_link(struct kernfs_node parent, const char name,
	struct kernfs_node *target)
	{ return ERR_PTR(-ENOSYS); }

	static inline void kernfs_remove(struct kernfs_node *kn) { }

	static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn,
	const char name, const void ns)
	{ return -ENOSYS; }

	static inline int kernfs_rename_ns(struct kernfs_node *kn,
	struct kernfs_node *new_parent,
	const char new_name, const void new_ns)
	{ return -ENOSYS; }

	static inline int kernfs_setattr(struct kernfs_node *kn,
	const struct iattr *iattr)
	{ return -ENOSYS; }

	static inline void kernfs_notify(struct kernfs_node *kn) { }

	static inline const void kernfs_super_ns(struct super_block sb)
	{ return NULL; }

	static inline struct dentry *
	kernfs_mount_ns(struct file_system_type *fs_type, int flags,
	struct kernfs_root root, const void ns)
	{ return ERR_PTR(-ENOSYS); }

	static inline void kernfs_kill_sb(struct super_block *sb) { }

	static inline void kernfs_init(void) { }

	#endif /* CONFIG_SYSFS */

	static inline struct kernfs_node *
	kernfs_find_and_get(struct kernfs_node kn, const char name)
	{
	return kernfs_find_and_get_ns(kn, name, NULL);
	}

	static inline struct kernfs_node *
	kernfs_create_dir(struct kernfs_node parent, const char name, void *priv)
	{
	return kernfs_create_dir_ns(parent, name, priv, NULL);
	}

	static inline struct kernfs_node *
	kernfs_create_file_ns(struct kernfs_node parent, const char name,
	umode_t mode, loff_t size, const struct kernfs_ops *ops,
	void priv, const void ns)
	{
	struct lock_class_key *key = NULL;

	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	key = (struct lock_class_key *)&ops->lockdep_key;
	#endif
	return kernfs_create_file_ns_key(parent, name, mode, size, ops, priv,
	ns, key);
	}

	static inline struct kernfs_node *
	kernfs_create_file(struct kernfs_node parent, const char name, umode_t mode,
	loff_t size, const struct kernfs_ops ops, void priv)
	{
	return kernfs_create_file_ns(parent, name, mode, size, ops, priv, NULL);
	}

	static inline int kernfs_remove_by_name(struct kernfs_node *parent,
	const char *name)
	{
	return kernfs_remove_by_name_ns(parent, name, NULL);
	}

	static inline struct dentry *
	kernfs_mount(struct file_system_type *fs_type, int flags,
	struct kernfs_root *root)
	{
	return kernfs_mount_ns(fs_type, flags, root, NULL);
	}

	#endif /* __LINUX_KERNFS_H */