/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * configfs_internal.h - Internal stuff for configfs
 *
 * Based on sysfs:
 *      sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
 *
 * configfs Copyright (C) 2005 Oracle.  All rights reserved.
 */

#ifdef pr_fmt
#undef pr_fmt
#endif

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/slab.h>
#include <linux/list.h>
#include <linux/spinlock.h>

struct configfs_fragment {
        atomic_t frag_count;
        struct rw_semaphore frag_sem;
        bool frag_dead;
};

void put_fragment(struct configfs_fragment *);
struct configfs_fragment *get_fragment(struct configfs_fragment *);

struct configfs_dirent {
        atomic_t                s_count;
        int                     s_dependent_count;
        struct list_head        s_sibling;
        struct list_head        s_children;
        int                     s_links;
        void                    * s_element;
        int                     s_type;
        umode_t                 s_mode;
        struct dentry           * s_dentry;
        struct iattr            * s_iattr;
#ifdef CONFIG_LOCKDEP
        int                     s_depth;
#endif
        struct configfs_fragment *s_frag;
};

#define CONFIGFS_ROOT           0x0001
#define CONFIGFS_DIR            0x0002
#define CONFIGFS_ITEM_ATTR      0x0004
#define CONFIGFS_ITEM_BIN_ATTR  0x0008
#define CONFIGFS_ITEM_LINK      0x0020
#define CONFIGFS_USET_DIR       0x0040
#define CONFIGFS_USET_DEFAULT   0x0080
#define CONFIGFS_USET_DROPPING  0x0100
#define CONFIGFS_USET_IN_MKDIR  0x0200
#define CONFIGFS_USET_CREATING  0x0400
#define CONFIGFS_NOT_PINNED     (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)
#define CONFIGFS_PINNED \
        (CONFIGFS_ROOT | CONFIGFS_DIR | CONFIGFS_ITEM_LINK)

extern struct mutex configfs_symlink_mutex;
extern spinlock_t configfs_dirent_lock;

extern struct kmem_cache *configfs_dir_cachep;

extern int configfs_is_root(struct config_item *item);

extern struct inode * configfs_new_inode(umode_t mode, struct configfs_dirent *, struct super_block *);
extern struct inode *configfs_create(struct dentry *, umode_t mode);

extern int configfs_create_file(struct config_item *, const struct configfs_attribute *);
extern int configfs_create_bin_file(struct config_item *,
                                    const struct configfs_bin_attribute *);
extern int configfs_make_dirent(struct configfs_dirent *, struct dentry *,
                                void *, umode_t, int, struct configfs_fragment *);
extern int configfs_dirent_is_ready(struct configfs_dirent *);

extern const unsigned char * configfs_get_name(struct configfs_dirent *sd);
extern void configfs_drop_dentry(struct configfs_dirent *sd, struct dentry *parent);
extern int configfs_setattr(struct mnt_idmap *idmap,
                            struct dentry *dentry, struct iattr *iattr);

extern struct dentry *configfs_pin_fs(void);
extern void configfs_release_fs(void);

extern const struct file_operations configfs_dir_operations;
extern const struct file_operations configfs_file_operations;
extern const struct file_operations configfs_bin_file_operations;
extern const struct inode_operations configfs_dir_inode_operations;
extern const struct inode_operations configfs_root_inode_operations;
extern const struct inode_operations configfs_symlink_inode_operations;
extern const struct dentry_operations configfs_dentry_ops;

extern int configfs_symlink(struct mnt_idmap *idmap,
                            struct inode *dir, struct dentry *dentry,
                            const char *symname);
extern int configfs_unlink(struct inode *dir, struct dentry *dentry);

int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
                struct dentry *dentry, char *body);

static inline struct config_item * to_item(struct dentry * dentry)
{
        struct configfs_dirent * sd = dentry->d_fsdata;
        return ((struct config_item *) sd->s_element);
}

static inline struct configfs_attribute * to_attr(struct dentry * dentry)
{
        struct configfs_dirent * sd = dentry->d_fsdata;
        return ((struct configfs_attribute *) sd->s_element);
}

static inline struct configfs_bin_attribute *to_bin_attr(struct dentry *dentry)
{
        struct configfs_attribute *attr = to_attr(dentry);

        return container_of(attr, struct configfs_bin_attribute, cb_attr);
}

static inline struct config_item *configfs_get_config_item(struct dentry *dentry)
{
        struct config_item * item = NULL;

        spin_lock(&dentry->d_lock);
        if (!d_unhashed(dentry)) {
                struct configfs_dirent * sd = dentry->d_fsdata;
                item = config_item_get(sd->s_element);
        }
        spin_unlock(&dentry->d_lock);

        return item;
}

static inline void release_configfs_dirent(struct configfs_dirent * sd)
{
        if (!(sd->s_type & CONFIGFS_ROOT)) {
                kfree(sd->s_iattr);
                put_fragment(sd->s_frag);
                kmem_cache_free(configfs_dir_cachep, sd);
        }
}

static inline struct configfs_dirent * configfs_get(struct configfs_dirent * sd)
{
        if (sd) {
                WARN_ON(!atomic_read(&sd->s_count));
                atomic_inc(&sd->s_count);
        }
        return sd;
}

static inline void configfs_put(struct configfs_dirent * sd)
{
        WARN_ON(!atomic_read(&sd->s_count));
        if (atomic_dec_and_test(&sd->s_count))
                release_configfs_dirent(sd);
}