fs/configfs/configfs_internal.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * configfs_internal.h - Internal stuff for configfs
   4  *
   5  * Based on sysfs:
   6  *      sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
   7  *
   8  * configfs Copyright (C) 2005 Oracle.  All rights reserved.
   9  */
  10
  11 #ifdef pr_fmt
  12 #undef pr_fmt
  13 #endif
  14
  15 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  16
  17 #include <linux/slab.h>
  18 #include <linux/list.h>
  19 #include <linux/spinlock.h>
  20
  21 struct configfs_fragment {
  22         atomic_t frag_count;
  23         struct rw_semaphore frag_sem;
  24         bool frag_dead;
  25 };
  26
  27 void put_fragment(struct configfs_fragment *);
  28 struct configfs_fragment *get_fragment(struct configfs_fragment *);
  29
  30 struct configfs_dirent {
  31         atomic_t                s_count;
  32         int                     s_dependent_count;
  33         struct list_head        s_sibling;
  34         struct list_head        s_children;
  35         int                     s_links;
  36         void                    * s_element;
  37         int                     s_type;
  38         umode_t                 s_mode;
  39         struct dentry           * s_dentry;
  40         struct iattr            * s_iattr;
  41 #ifdef CONFIG_LOCKDEP
  42         int                     s_depth;
  43 #endif
  44         struct configfs_fragment *s_frag;
  45 };
  46
  47 #define CONFIGFS_ROOT           0x0001
  48 #define CONFIGFS_DIR            0x0002
  49 #define CONFIGFS_ITEM_ATTR      0x0004
  50 #define CONFIGFS_ITEM_BIN_ATTR  0x0008
  51 #define CONFIGFS_ITEM_LINK      0x0020
  52 #define CONFIGFS_USET_DIR       0x0040
  53 #define CONFIGFS_USET_DEFAULT   0x0080
  54 #define CONFIGFS_USET_DROPPING  0x0100
  55 #define CONFIGFS_USET_IN_MKDIR  0x0200
  56 #define CONFIGFS_USET_CREATING  0x0400
  57 #define CONFIGFS_NOT_PINNED     (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)
  58 #define CONFIGFS_PINNED \
  59         (CONFIGFS_ROOT | CONFIGFS_DIR | CONFIGFS_ITEM_LINK)
  60
  61 extern struct mutex configfs_symlink_mutex;
  62 extern spinlock_t configfs_dirent_lock;
  63
  64 extern struct kmem_cache *configfs_dir_cachep;
  65
  66 extern int configfs_is_root(struct config_item *item);
  67
  68 extern struct inode * configfs_new_inode(umode_t mode, struct configfs_dirent *, struct super_block *);
  69 extern struct inode *configfs_create(struct dentry *, umode_t mode);
  70
  71 extern int configfs_create_file(struct config_item *, const struct configfs_attribute *);
  72 extern int configfs_create_bin_file(struct config_item *,
  73                                     const struct configfs_bin_attribute *);
  74 extern int configfs_make_dirent(struct configfs_dirent *, struct dentry *,
  75                                 void *, umode_t, int, struct configfs_fragment *);
  76 extern int configfs_dirent_is_ready(struct configfs_dirent *);
  77
  78 extern const unsigned char * configfs_get_name(struct configfs_dirent *sd);
  79 extern void configfs_drop_dentry(struct configfs_dirent *sd, struct dentry *parent);
  80 extern int configfs_setattr(struct mnt_idmap *idmap,
  81                             struct dentry *dentry, struct iattr *iattr);
  82
  83 extern struct dentry *configfs_pin_fs(void);
  84 extern void configfs_release_fs(void);
  85
  86 extern const struct file_operations configfs_dir_operations;
  87 extern const struct file_operations configfs_file_operations;
  88 extern const struct file_operations configfs_bin_file_operations;
  89 extern const struct inode_operations configfs_dir_inode_operations;
  90 extern const struct inode_operations configfs_root_inode_operations;
  91 extern const struct inode_operations configfs_symlink_inode_operations;
  92 extern const struct dentry_operations configfs_dentry_ops;
  93
  94 extern int configfs_symlink(struct mnt_idmap *idmap,
  95                             struct inode *dir, struct dentry *dentry,
  96                             const char *symname);
  97 extern int configfs_unlink(struct inode *dir, struct dentry *dentry);
  98
  99 int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
 100                 struct dentry *dentry, char *body);
 101
 102 static inline struct config_item * to_item(struct dentry * dentry)
 103 {
 104         struct configfs_dirent * sd = dentry->d_fsdata;
 105         return ((struct config_item *) sd->s_element);
 106 }
 107
 108 static inline struct configfs_attribute * to_attr(struct dentry * dentry)
 109 {
 110         struct configfs_dirent * sd = dentry->d_fsdata;
 111         return ((struct configfs_attribute *) sd->s_element);
 112 }
 113
 114 static inline struct configfs_bin_attribute *to_bin_attr(struct dentry *dentry)
 115 {
 116         struct configfs_attribute *attr = to_attr(dentry);
 117
 118         return container_of(attr, struct configfs_bin_attribute, cb_attr);
 119 }
 120
 121 static inline struct config_item *configfs_get_config_item(struct dentry *dentry)
 122 {
 123         struct config_item * item = NULL;
 124
 125         spin_lock(&dentry->d_lock);
 126         if (!d_unhashed(dentry)) {
 127                 struct configfs_dirent * sd = dentry->d_fsdata;
 128                 item = config_item_get(sd->s_element);
 129         }
 130         spin_unlock(&dentry->d_lock);
 131
 132         return item;
 133 }
 134
 135 static inline void release_configfs_dirent(struct configfs_dirent * sd)
 136 {
 137         if (!(sd->s_type & CONFIGFS_ROOT)) {
 138                 kfree(sd->s_iattr);
 139                 put_fragment(sd->s_frag);
 140                 kmem_cache_free(configfs_dir_cachep, sd);
 141         }
 142 }
 143
 144 static inline struct configfs_dirent * configfs_get(struct configfs_dirent * sd)
 145 {
 146         if (sd) {
 147                 WARN_ON(!atomic_read(&sd->s_count));
 148                 atomic_inc(&sd->s_count);
 149         }
 150         return sd;
 151 }
 152
 153 static inline void configfs_put(struct configfs_dirent * sd)
 154 {
 155         WARN_ON(!atomic_read(&sd->s_count));
 156         if (atomic_dec_and_test(&sd->s_count))
 157                 release_configfs_dirent(sd);
 158 }
 159