linux/drivers/mtd/ubi/cdev.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) International Business Machines Corp., 2006
 *
 * Author: Artem Bityutskiy (Битюцкий Артём)
 */

/*
 * This file includes implementation of UBI character device operations.
 *
 * There are two kinds of character devices in UBI: UBI character devices and
 * UBI volume character devices. UBI character devices allow users to
 * manipulate whole volumes: create, remove, and re-size them. Volume character
 * devices provide volume I/O capabilities.
 *
 * Major and minor numbers are assigned dynamically to both UBI and volume
 * character devices.
 *
 * Well, there is the third kind of character devices - the UBI control
 * character device, which allows to manipulate by UBI devices - create and
 * delete them. In other words, it is used for attaching and detaching MTD
 * devices.
 */

#include <linux/module.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/ioctl.h>
#include <linux/capability.h>
#include <linux/uaccess.h>
#include <linux/compat.h>
#include <linux/math64.h>
#include <mtd/ubi-user.h>
#include "ubi.h"

/**
 * get_exclusive - get exclusive access to an UBI volume.
 * @desc: volume descriptor
 *
 * This function changes UBI volume open mode to "exclusive". Returns previous
 * mode value (positive integer) in case of success and a negative error code
 * in case of failure.
 */
static int get_exclusive(struct ubi_volume_desc *desc)
{ … }

/**
 * revoke_exclusive - revoke exclusive mode.
 * @desc: volume descriptor
 * @mode: new mode to switch to
 */
static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
{ … }

static int vol_cdev_open(struct inode *inode, struct file *file)
{ … }

static int vol_cdev_release(struct inode *inode, struct file *file)
{ … }

static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
{ … }

static int vol_cdev_fsync(struct file *file, loff_t start, loff_t end,
			  int datasync)
{ … }


static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
			     loff_t *offp)
{ … }

/*
 * This function allows to directly write to dynamic UBI volumes, without
 * issuing the volume update operation.
 */
static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
				     size_t count, loff_t *offp)
{ … }

static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
			      size_t count, loff_t *offp)
{ … }

static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
			   unsigned long arg)
{ … }

/**
 * verify_mkvol_req - verify volume creation request.
 * @ubi: UBI device description object
 * @req: the request to check
 *
 * This function zero if the request is correct, and %-EINVAL if not.
 */
static int verify_mkvol_req(const struct ubi_device *ubi,
			    const struct ubi_mkvol_req *req)
{ … }

/**
 * verify_rsvol_req - verify volume re-size request.
 * @ubi: UBI device description object
 * @req: the request to check
 *
 * This function returns zero if the request is correct, and %-EINVAL if not.
 */
static int verify_rsvol_req(const struct ubi_device *ubi,
			    const struct ubi_rsvol_req *req)
{ … }

/**
 * rename_volumes - rename UBI volumes.
 * @ubi: UBI device description object
 * @req: volumes re-name request
 *
 * This is a helper function for the volume re-name IOCTL which validates the
 * request, opens the volume and calls corresponding volumes management
 * function. Returns zero in case of success and a negative error code in case
 * of failure.
 */
static int rename_volumes(struct ubi_device *ubi,
			  struct ubi_rnvol_req *req)
{ … }

static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
			   unsigned long arg)
{ … }

static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
			    unsigned long arg)
{ … }

/* UBI volume character device operations */
const struct file_operations ubi_vol_cdev_operations = …;

/* UBI character device operations */
const struct file_operations ubi_cdev_operations = …;

/* UBI control character device operations */
const struct file_operations ubi_ctrl_cdev_operations = …;