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sysfs, kernfs: make sysfs_dirent definition public
sysfs_dirent includes some information which should be available to
kernfs users - the type, flags, name and parent pointer. This patch
moves sysfs_dirent definition from kernfs/kernfs-internal.h to
include/linux/kernfs.h so that kernfs users can access them.
The type part of flags is exported as enum kernfs_node_type, the flags
kernfs_node_flag, sysfs_type() and kernfs_enable_ns() are moved to
include/linux/kernfs.h and the former is updated to return the enum
type. sysfs_dirent->s_parent and ->s_name are marked explicitly as
public.
This patch doesn't introduce any functional changes.
v2: Flags exported too and kernfs_enable_ns() definition moved.
v3: While moving kernfs_enable_ns() to include/linux/kernfs.h, v1 and
v2 put the definition outside CONFIG_SYSFS replacing the dummy
implementation with the actual implementation too. Unfortunately,
this can lead to oops when !CONFIG_SYSFS because
kernfs_enable_ns() may be called on a NULL @sd and now tries to
dereference @sd instead of not doing anything. This issue was
reported by Yuanhan Liu.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tejun Heo
Greg Kroah-Hartman
parent
fa736a951e
commit
cf9e5a73aa
@ -895,21 +895,6 @@ int kernfs_rename_ns(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent,
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return error;
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}
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/**
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* kernfs_enable_ns - enable namespace under a directory
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* @sd: directory of interest, should be empty
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*
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* This is to be called right after @sd is created to enable namespace
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* under it. All children of @sd must have non-NULL namespace tags and
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* only the ones which match the super_block's tag will be visible.
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*/
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void kernfs_enable_ns(struct sysfs_dirent *sd)
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{
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WARN_ON_ONCE(sysfs_type(sd) != SYSFS_DIR);
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WARN_ON_ONCE(!RB_EMPTY_ROOT(&sd->s_dir.children));
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sd->s_flags |= SYSFS_FLAG_NS;
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}
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/* Relationship between s_mode and the DT_xxx types */
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static inline unsigned char dt_type(struct sysfs_dirent *sd)
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{
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@ -13,102 +13,19 @@
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#include <linux/lockdep.h>
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#include <linux/fs.h>
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#include <linux/rbtree.h>
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#include <linux/mutex.h>
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#include <linux/kernfs.h>
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struct sysfs_open_dirent;
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/* type-specific structures for sysfs_dirent->s_* union members */
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struct sysfs_elem_dir {
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unsigned long subdirs;
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/* children rbtree starts here and goes through sd->s_rb */
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struct rb_root children;
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/*
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* The kernfs hierarchy this directory belongs to. This fits
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* better directly in sysfs_dirent but is here to save space.
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*/
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struct kernfs_root *root;
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};
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struct sysfs_elem_symlink {
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struct sysfs_dirent *target_sd;
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};
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struct sysfs_elem_attr {
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const struct kernfs_ops *ops;
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struct sysfs_open_dirent *open;
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loff_t size;
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};
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struct sysfs_inode_attrs {
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struct iattr ia_iattr;
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void *ia_secdata;
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u32 ia_secdata_len;
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};
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/*
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* sysfs_dirent - the building block of sysfs hierarchy. Each and
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* every sysfs node is represented by single sysfs_dirent.
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*
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* As long as s_count reference is held, the sysfs_dirent itself is
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* accessible. Dereferencing s_elem or any other outer entity
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* requires s_active reference.
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*/
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struct sysfs_dirent {
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atomic_t s_count;
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atomic_t s_active;
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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struct lockdep_map dep_map;
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#endif
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struct sysfs_dirent *s_parent;
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const char *s_name;
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struct rb_node s_rb;
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union {
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struct completion *completion;
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struct sysfs_dirent *removed_list;
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} u;
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const void *s_ns; /* namespace tag */
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unsigned int s_hash; /* ns + name hash */
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union {
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struct sysfs_elem_dir s_dir;
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struct sysfs_elem_symlink s_symlink;
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struct sysfs_elem_attr s_attr;
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};
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void *priv;
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unsigned short s_flags;
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umode_t s_mode;
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unsigned int s_ino;
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struct sysfs_inode_attrs *s_iattr;
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};
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#define SD_DEACTIVATED_BIAS INT_MIN
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#define SYSFS_TYPE_MASK 0x000f
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#define SYSFS_DIR 0x0001
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#define SYSFS_KOBJ_ATTR 0x0002
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#define SYSFS_KOBJ_LINK 0x0004
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#define SYSFS_COPY_NAME (SYSFS_DIR | SYSFS_KOBJ_LINK)
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#define SYSFS_ACTIVE_REF SYSFS_KOBJ_ATTR
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#define SYSFS_FLAG_MASK ~SYSFS_TYPE_MASK
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#define SYSFS_FLAG_REMOVED 0x0010
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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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/* SYSFS_TYPE_MASK and types are defined in include/linux/kernfs.h */
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/**
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* kernfs_root - find out the kernfs_root a sysfs_dirent belongs to
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@ -13,6 +13,9 @@
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#include <linux/mutex.h>
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#include <linux/idr.h>
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#include <linux/lockdep.h>
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#include <linux/rbtree.h>
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#include <linux/atomic.h>
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#include <linux/completion.h>
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struct file;
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struct iattr;
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@ -21,7 +24,92 @@ struct vm_area_struct;
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struct super_block;
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struct file_system_type;
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struct sysfs_dirent;
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struct sysfs_open_dirent;
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struct sysfs_inode_attrs;
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enum kernfs_node_type {
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SYSFS_DIR = 0x0001,
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SYSFS_KOBJ_ATTR = 0x0002,
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SYSFS_KOBJ_LINK = 0x0004,
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};
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#define SYSFS_TYPE_MASK 0x000f
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#define SYSFS_COPY_NAME (SYSFS_DIR | SYSFS_KOBJ_LINK)
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#define SYSFS_ACTIVE_REF SYSFS_KOBJ_ATTR
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#define SYSFS_FLAG_MASK ~SYSFS_TYPE_MASK
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enum kernfs_node_flag {
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SYSFS_FLAG_REMOVED = 0x0010,
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SYSFS_FLAG_NS = 0x0020,
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SYSFS_FLAG_HAS_SEQ_SHOW = 0x0040,
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SYSFS_FLAG_HAS_MMAP = 0x0080,
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SYSFS_FLAG_LOCKDEP = 0x0100,
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};
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/* type-specific structures for sysfs_dirent->s_* union members */
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struct sysfs_elem_dir {
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unsigned long subdirs;
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/* children rbtree starts here and goes through sd->s_rb */
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struct rb_root children;
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/*
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* The kernfs hierarchy this directory belongs to. This fits
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* better directly in sysfs_dirent but is here to save space.
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*/
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struct kernfs_root *root;
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};
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struct sysfs_elem_symlink {
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struct sysfs_dirent *target_sd;
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};
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struct sysfs_elem_attr {
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const struct kernfs_ops *ops;
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struct sysfs_open_dirent *open;
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loff_t size;
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};
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/*
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* sysfs_dirent - the building block of sysfs hierarchy. Each and every
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* sysfs node is represented by single sysfs_dirent. Most fields are
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* private to kernfs and shouldn't be accessed directly by kernfs users.
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*
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* As long as s_count reference is held, the sysfs_dirent itself is
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* accessible. Dereferencing s_elem or any other outer entity
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* requires s_active reference.
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*/
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struct sysfs_dirent {
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atomic_t s_count;
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atomic_t s_active;
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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struct lockdep_map dep_map;
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#endif
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/* the following two fields are published */
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struct sysfs_dirent *s_parent;
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const char *s_name;
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struct rb_node s_rb;
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union {
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struct completion *completion;
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struct sysfs_dirent *removed_list;
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} u;
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const void *s_ns; /* namespace tag */
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unsigned int s_hash; /* ns + name hash */
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union {
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struct sysfs_elem_dir s_dir;
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struct sysfs_elem_symlink s_symlink;
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struct sysfs_elem_attr s_attr;
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};
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void *priv;
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unsigned short s_flags;
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umode_t s_mode;
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unsigned int s_ino;
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struct sysfs_inode_attrs *s_iattr;
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};
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struct kernfs_root {
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/* published fields */
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@ -82,6 +170,26 @@ struct kernfs_ops {
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#ifdef CONFIG_SYSFS
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static inline enum kernfs_node_type 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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/**
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* kernfs_enable_ns - enable namespace under a directory
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* @sd: directory of interest, should be empty
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*
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* This is to be called right after @sd is created to enable namespace
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* under it. All children of @sd must have non-NULL namespace tags and
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* only the ones which match the super_block's tag will be visible.
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*/
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static inline void kernfs_enable_ns(struct sysfs_dirent *sd)
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{
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WARN_ON_ONCE(sysfs_type(sd) != SYSFS_DIR);
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WARN_ON_ONCE(!RB_EMPTY_ROOT(&sd->s_dir.children));
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sd->s_flags |= SYSFS_FLAG_NS;
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}
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struct sysfs_dirent *kernfs_find_and_get_ns(struct sysfs_dirent *parent,
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const char *name, const void *ns);
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void kernfs_get(struct sysfs_dirent *sd);
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@ -107,7 +215,6 @@ int kernfs_remove_by_name_ns(struct sysfs_dirent *parent, const char *name,
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const void *ns);
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int kernfs_rename_ns(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent,
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const char *new_name, const void *new_ns);
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void kernfs_enable_ns(struct sysfs_dirent *sd);
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int kernfs_setattr(struct sysfs_dirent *sd, const struct iattr *iattr);
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void kernfs_notify(struct sysfs_dirent *sd);
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@ -120,6 +227,11 @@ void kernfs_init(void);
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#else /* CONFIG_SYSFS */
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static inline enum kernfs_node_type sysfs_type(struct sysfs_dirent *sd)
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{ return 0; } /* whatever */
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static inline void kernfs_enable_ns(struct sysfs_dirent *sd) { }
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static inline struct sysfs_dirent *
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kernfs_find_and_get_ns(struct sysfs_dirent *parent, const char *name,
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const void *ns)
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@ -161,8 +273,6 @@ static inline int kernfs_rename_ns(struct sysfs_dirent *sd,
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const char *new_name, const void *new_ns)
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{ return -ENOSYS; }
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static inline void kernfs_enable_ns(struct sysfs_dirent *sd) { }
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static inline int kernfs_setattr(struct sysfs_dirent *sd,
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const struct iattr *iattr)
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{ return -ENOSYS; }
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