[PATCH 14/20 take 4] UBI: character devices functionality

Artem Bityutskiy
2007-03-23T16:51:05Z

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diff -auNrp tmp-from/drivers/mtd/ubi/cdev.c tmp-to/drivers/mtd/ubi/cdev.c
--- tmp-from/drivers/mtd/ubi/cdev.c 1970-01-01 02:00:00.000000000 +0200
+++ tmp-to/drivers/mtd/ubi/cdev.c 2007-03-23 18:20:02.000000000 +0200
@@ -0,0 +1,724 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/stat.h>
+#include <linux/ioctl.h>
+#include <linux/capability.h>
+#include <mtd/ubi-user.h>
+#include <asm/uaccess.h>
+#include <asm/div64.h>
+#include "ubi.h"
+
+/*
+ * Maximum sequence numbers of UBI and volume character device IOCTLs (direct
+ * logical eraseblock erase is a debug-only feature).
+ */
+#define UBI_CDEV_IOC_MAX_SEQ 2
+#ifndef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
+#define VOL_CDEV_IOC_MAX_SEQ 1
+#else
+#define VOL_CDEV_IOC_MAX_SEQ 2
+#endif
+
+/**
+ * major_to_device - get UBI device object by character device major number.
+ * @major: major number
+ *
+ * This function returns a pointer to the UBI device object.
+ */
+static struct ubi_device *major_to_device(int major)
+{
+ int i;
+
+ for (i = 0; i < ubi_devices_cnt; i++)
+ if (ubi_devices[i] && ubi_devices[i]->major == major)
+ return ubi_devices[i];
+ BUG();
+}
+
+/**
+ * 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)
+{
+ int users, err;
+ struct ubi_volume *vol = desc->vol;
+
+ spin_lock(&vol->ubi->volumes_lock);
+ users = vol->readers + vol->writers + vol->exclusive;
+ ubi_assert(users > 0);
+ if (users > 1) {
+ dbg_err("%d users for volume %d", users, vol->vol_id);
+ err = -EBUSY;
+ } else {
+ vol->readers = vol->writers = 0;
+ vol->exclusive = 1;
+ err = desc->mode;
+ desc->mode = UBI_EXCLUSIVE;
+ }
+ spin_unlock(&vol->ubi->volumes_lock);
+
+ return err;
+}
+
+/**
+ * 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)
+{
+ struct ubi_volume *vol = desc->vol;
+
+ spin_lock(&vol->ubi->volumes_lock);
+ ubi_assert(vol->readers == 0 && vol->writers == 0);
+ ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
+ vol->exclusive = 0;
+ if (mode == UBI_READONLY)
+ vol->readers = 1;
+ else if (mode == UBI_READWRITE)
+ vol->writers = 1;
+ else
+ vol->exclusive = 1;
+ spin_unlock(&vol->ubi->volumes_lock);
+
+ desc->mode = mode;
+}
+
+static int vol_cdev_open(struct inode *inode, struct file *file)
+{
+ struct ubi_volume_desc *desc;
+ const struct ubi_device *ubi = major_to_device(imajor(inode));
+ int vol_id = iminor(inode) - 1;
+ int mode;
+
+ if (file->f_mode & FMODE_WRITE)
+ mode = UBI_READWRITE;
+ else
+ mode = UBI_READONLY;
+
+ dbg_msg("open volume %d, mode %d", vol_id, mode);
+
+ desc = ubi_open_volume(ubi->ubi_num, vol_id, mode);
+ if (IS_ERR(desc))
+ return PTR_ERR(desc);
+
+ file->private_data = desc;
+ return 0;
+}
+
+static int vol_cdev_release(struct inode *inode, struct file *file)
+{
+ struct ubi_volume_desc *desc = file->private_data;
+ struct ubi_volume *vol = desc->vol;
+
+ dbg_msg("release volume %d, mode %d", vol->vol_id, desc->mode);
+
+ if (vol->updating) {
+ ubi_warn("update of volume %d not finished, volume is damaged",
+ vol->vol_id);
+ vol->updating = 0;
+ kfree(vol->upd_buf);
+ }
+
+ ubi_close_volume(desc);
+ return 0;
+}
+
+static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
+{
+ struct ubi_volume_desc *desc = file->private_data;
+ struct ubi_volume *vol = desc->vol;
+ loff_t new_offset;
+
+ if (vol->updating) {
+ /* Update is in progress, seeking is prohibited */
+ dbg_err("updating");
+ return -EBUSY;
+ }
+
+ switch (origin) {
+ case 0: /* SEEK_SET */
+ new_offset = offset;
+ break;
+ case 1: /* SEEK_CUR */
+ new_offset = file->f_pos + offset;
+ break;
+ case 2: /* SEEK_END */
+ new_offset = vol->used_bytes + offset;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (new_offset < 0 || new_offset > vol->used_bytes) {
+ dbg_err("bad seek %lld", new_offset);
+ return -EINVAL;
+ }
+
+ dbg_msg("seek volume %d, offset %lld, origin %d, new offset %lld",
+ vol->vol_id, offset, origin, new_offset);
+
+ file->f_pos = new_offset;
+ return new_offset;
+}
+
+static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
+ loff_t *offp)
+{
+ struct ubi_volume_desc *desc = file->private_data;
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+ int err, lnum, off, len, vol_id = desc->vol->vol_id, tbuf_size;
+ size_t count_save = count;
+ void *tbuf;
+ uint64_t tmp;
+
+ dbg_msg("read %zd bytes from offset %lld of volume %d",
+ count, *offp, vol_id);
+
+ if (vol->updating) {
+ dbg_err("updating");
+ return -EBUSY;
+ }
+ if (vol->upd_marker) {
+ dbg_err("damaged volume, update marker is set");
+ return -EBADF;
+ }
+ if (*offp == vol->used_bytes || count == 0)
+ return 0;
+
+ if (vol->corrupted)
+ dbg_msg("read from corrupted volume %d", vol_id);
+
+ if (*offp + count > vol->used_bytes)
+ count_save = count = vol->used_bytes - *offp;
+
+ tbuf_size = vol->usable_leb_size;
+ if (count < tbuf_size)
+ tbuf_size = ubi_align_up(count, ubi->min_io_size);
+ tbuf = kmalloc(tbuf_size, GFP_KERNEL);
+ if (!tbuf)
+ return -ENOMEM;
+
+ len = count > tbuf_size ? tbuf_size : count;
+
+ tmp = *offp;
+ off = do_div(tmp, vol->usable_leb_size);
+ lnum = tmp;
+
+ do {
+ cond_resched();
+
+ if (off + len >= vol->usable_leb_size)
+ len = vol->usable_leb_size - off;
+
+ err = ubi_eba_read_leb(ubi, vol_id, lnum, tbuf, off, len, 0);
+ if (unlikely(err))
+ break;
+
+ off += len;
+ if (off == vol->usable_leb_size) {
+ lnum += 1;
+ off -= vol->usable_leb_size;
+ }
+
+ count -= len;
+ *offp += len;
+
+ err = copy_to_user(buf, tbuf, len);
+ if (unlikely(err)) {
+ err = -EFAULT;
+ break;
+ }
+
+ buf += len;
+ len = count > tbuf_size ? tbuf_size : count;
+ } while (count);
+
+ kfree(tbuf);
+ return err ? err : count_save - count;
+}
+
+#ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
+
+/*
+ * This function allows to directly write to dynamic UBI volumes, without
+ * issuing the volume update operation. Available only as a debugging feature.
+ * Very useful for testing UBI.
+ */
+static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *offp)
+{
+ struct ubi_volume_desc *desc = file->private_data;
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+ int lnum, off, len, tbuf_size, vol_id = vol->vol_id, err = 0;
+ size_t count_save = count;
+ char *tbuf;
+ uint64_t tmp;
+
+ dbg_msg("requested: write %zd bytes to offset %lld of volume %u",
+ count, *offp, desc->vol->vol_id);
+
+ if (vol->vol_type == UBI_STATIC_VOLUME)
+ return -EROFS;
+
+ tmp = *offp;
+ off = do_div(tmp, vol->usable_leb_size);
+ lnum = tmp;
+
+ if (off % ubi->min_io_size) {
+ dbg_err("unaligned position");
+ return -EINVAL;
+ }
+
+ if (*offp + count > vol->used_bytes)
+ count_save = count = vol->used_bytes - *offp;
+
+ /* We can write only in fractions of the minimum I/O unit */
+ if (count % ubi->min_io_size) {
+ dbg_err("unaligned write length");
+ return -EINVAL;
+ }
+
+ tbuf_size = vol->usable_leb_size;
+ if (count < tbuf_size)
+ tbuf_size = ubi_align_up(count, ubi->min_io_size);
+ tbuf = kmalloc(tbuf_size, GFP_KERNEL);
+ if (!tbuf)
+ return -ENOMEM;
+
+ len = count > tbuf_size ? tbuf_size : count;
+
+ while (count) {
+ cond_resched();
+
+ if (off + len >= vol->usable_leb_size)
+ len = vol->usable_leb_size - off;
+
+ err = copy_from_user(tbuf, buf, len);
+ if (err) {
+ err = -EFAULT;
+ break;
+ }
+
+ err = ubi_eba_write_leb(ubi, vol_id, lnum, tbuf, off, len,
+ UBI_DATA_UNKNOWN);
+ if (unlikely(err))
+ break;
+
+ off += len;
+ if (off == vol->usable_leb_size) {
+ lnum += 1;
+ off -= vol->usable_leb_size;
+ }
+
+ count -= len;
+ *offp += len;
+ buf += len;
+ len = count > tbuf_size ? tbuf_size : count;
+ }
+
+ kfree(tbuf);
+ return err ? err : count_save - count;
+}
+
+#else
+#define vol_cdev_direct_write(file, buf, count, offp) -EPERM
+#endif /* CONFIG_MTD_UBI_DEBUG_USERSPACE_IO */
+
+static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *offp)
+{
+ int err = 0;
+ struct ubi_volume_desc *desc = file->private_data;
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+
+ if (!vol->updating)
+ return vol_cdev_direct_write(file, buf, count, offp);
+
+ err = ubi_more_update_data(ubi, vol->vol_id, buf, count);
+ if (err < 0) {
+ ubi_err("cannot write %zd bytes of update data", count);
+ return err;
+ }
+
+ if (err) {
+ /*
+ * Update is finished, @err contains number of actually written
+ * bytes now.
+ */
+ count = err;
+
+ err = ubi_check_volume(ubi, vol->vol_id);
+ if (err < 0)
+ return err;
+
+ if (err) {
+ ubi_warn("volume %d on UBI device %d is corrupted",
+ vol->vol_id, ubi->ubi_num);
+ vol->corrupted = 1;
+ }
+ vol->checked = 1;
+ revoke_exclusive(desc, UBI_READWRITE);
+ }
+
+ *offp += count;
+ return count;
+}
+
+static int vol_cdev_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ int err = 0;
+ struct ubi_volume_desc *desc = file->private_data;
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+ void __user *argp = (void __user *)arg;
+
+ if (_IOC_NR(cmd) > VOL_CDEV_IOC_MAX_SEQ ||
+ _IOC_TYPE(cmd) != UBI_VOL_IOC_MAGIC)
+ return -ENOTTY;
+
+ if (_IOC_DIR(cmd) && _IOC_READ)
+ err = !access_ok(VERIFY_WRITE, argp, _IOC_SIZE(cmd));
+ else if (_IOC_DIR(cmd) && _IOC_WRITE)
+ err = !access_ok(VERIFY_READ, argp, _IOC_SIZE(cmd));
+ if (err)
+ return -EFAULT;
+
+ switch (cmd) {
+
+ /* Volume update command */
+ case UBI_IOCVOLUP:
+ {
+ int64_t bytes, rsvd_bytes;
+
+ if (!capable(CAP_SYS_RESOURCE)) {
+ err = -EPERM;
+ break;
+ }
+
+ err = copy_from_user(&bytes, argp, sizeof(int64_t));
+ if (err) {
+ err = -EFAULT;
+ break;
+ }
+
+ if (desc->mode == UBI_READONLY) {
+ err = -EROFS;
+ break;
+ }
+
+ rsvd_bytes = vol->reserved_pebs * (ubi->leb_size-vol->data_pad);
+ if (bytes < 0 || bytes > rsvd_bytes) {
+ err = -EINVAL;
+ break;
+ }
+
+ err = get_exclusive(desc);
+ if (err < 0)
+ break;
+
+ err = ubi_start_update(ubi, vol->vol_id, bytes);
+ if (bytes == 0)
+ revoke_exclusive(desc, UBI_READWRITE);
+
+ file->f_pos = 0;
+ break;
+ }
+
+#ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
+ /* Logical eraseblock erasure command */
+ case UBI_IOCEBER:
+ {
+ int32_t lnum;
+
+ err = __get_user(lnum, (__user int32_t *)argp);
+ if (err) {
+ err = -EFAULT;
+ break;
+ }
+
+ if (desc->mode == UBI_READONLY) {
+ err = -EROFS;
+ break;
+ }
+
+ if (lnum < 0 || lnum >= vol->reserved_pebs) {
+ err = -EINVAL;
+ break;
+ }
+
+ if (vol->vol_type != UBI_DYNAMIC_VOLUME) {
+ err = -EROFS;
+ break;
+ }
+
+ dbg_msg("erase LEB %d:%d", vol->vol_id, lnum);
+ err = ubi_eba_unmap_leb(ubi, vol->vol_id, lnum);
+ if (err)
+ break;
+
+ err = ubi_wl_flush(ubi);
+ break;
+ }
+#endif
+
+ default:
+ err = -ENOTTY;
+ break;
+ }
+
+ return err;
+}
+
+/**
+ * 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)
+{
+ int n;
+
+ if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
+ req->name_len < 0)
+ goto bad;
+
+ if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
+ req->vol_id != UBI_VOL_NUM_AUTO)
+ goto bad;
+
+ if (req->alignment == 0)
+ goto bad;
+
+ if (req->bytes == 0)
+ goto bad;
+
+ if (req->vol_type != UBI_DYNAMIC_VOLUME &&
+ req->vol_type != UBI_STATIC_VOLUME)
+ goto bad;
+
+ if (req->alignment > ubi->leb_size)
+ goto bad;
+
+ n = req->alignment % ubi->min_io_size;
+ if (req->alignment != 1 && n)
+ goto bad;
+
+ if (req->name_len > UBI_VOL_NAME_MAX)
+ goto bad;
+
+ return 0;
+
+bad:
+ dbg_err("bad volume creation request");
+ ubi_dbg_dump_mkvol_req(req);
+ return -EINVAL;
+}
+
+/**
+ * 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)
+{
+ if (req->bytes <= 0)
+ return -EINVAL;
+
+ if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ int err = 0;
+ struct ubi_device *ubi;
+ struct ubi_volume_desc *desc;
+ void __user *argp = (void __user *)arg;
+
+ if (_IOC_NR(cmd) > UBI_CDEV_IOC_MAX_SEQ ||
+ _IOC_TYPE(cmd) != UBI_IOC_MAGIC)
+ return -ENOTTY;
+
+ if (_IOC_DIR(cmd) && _IOC_READ)
+ err = !access_ok(VERIFY_WRITE, argp, _IOC_SIZE(cmd));
+ else if (_IOC_DIR(cmd) && _IOC_WRITE)
+ err = !access_ok(VERIFY_READ, argp, _IOC_SIZE(cmd));
+ if (err)
+ return -EFAULT;
+
+ if (!capable(CAP_SYS_RESOURCE))
+ return -EPERM;
+
+ ubi = major_to_device(imajor(inode));
+ if (IS_ERR(ubi))
+ return PTR_ERR(ubi);
+
+ switch (cmd) {
+ /* Create volume command */
+ case UBI_IOCMKVOL:
+ {
+ struct ubi_mkvol_req req;
+
+ dbg_msg("create volume");
+ err = __copy_from_user(&req, argp,
+ sizeof(struct ubi_mkvol_req));
+ if (err) {
+ err = -EFAULT;
+ break;
+ }
+
+ err = verify_mkvol_req(ubi, &req);
+ if (err)
+ break;
+
+ req.name[req.name_len] = '\0';
+
+ err = ubi_create_volume(ubi, &req);
+ if (err)
+ break;
+
+ err = __put_user(req.vol_id, (__user int32_t *)argp);
+ if (err)
+ err = -EFAULT;
+
+ break;
+ }
+
+ /* Remove volume command */
+ case UBI_IOCRMVOL:
+ {
+ int vol_id;
+
+ dbg_msg("remove volume");
+ err = __get_user(vol_id, (__user int32_t *)argp);
+ if (err) {
+ err = -EFAULT;
+ break;
+ }
+
+ desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
+ if (IS_ERR(desc)) {
+ err = PTR_ERR(desc);
+ break;
+ }
+
+ err = ubi_remove_volume(desc);
+ if (err)
+ ubi_close_volume(desc);
+
+ break;
+ }
+
+ /* Re-size volume command */
+ case UBI_IOCRSVOL:
+ {
+ int pebs;
+ uint64_t tmp;
+ struct ubi_rsvol_req req;
+
+ dbg_msg("re-size volume");
+ err = __copy_from_user(&req, argp,
+ sizeof(struct ubi_rsvol_req));
+ if (err) {
+ err = -EFAULT;
+ break;
+ }
+
+ err = verify_rsvol_req(ubi, &req);
+ if (err)
+ break;
+
+ desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
+ if (IS_ERR(desc)) {
+ err = PTR_ERR(desc);
+ break;
+ }
+
+ tmp = req.bytes;
+ pebs = !!do_div(tmp, desc->vol->usable_leb_size);
+ pebs += tmp;
+
+dbg_msg("desc %p", desc);
+dbg_msg("desc->vol %p", desc->vol);
+dbg_msg("desc->vol->vol_id %d", desc->vol->vol_id);
+dbg_msg("desc->vol->ubi %d", desc->vol->ubi);
+ err = ubi_resize_volume(desc, pebs);
+ ubi_close_volume(desc);
+ break;
+ }
+
+ default:
+ err = -ENOTTY;
+ break;
+ }
+
+ return err;
+}
+
+/* UBI character device operations */
+struct file_operations ubi_cdev_operations = {
+ .owner = THIS_MODULE,
+ .ioctl = ubi_cdev_ioctl,
+ .llseek = no_llseek
+};
+
+/* UBI volume character device operations */
+struct file_operations ubi_vol_cdev_operations = {
+ .owner = THIS_MODULE,
+ .open = vol_cdev_open,
+ .release = vol_cdev_release,
+ .llseek = vol_cdev_llseek,
+ .read = vol_cdev_read,
+ .write = vol_cdev_write,
+ .ioctl = vol_cdev_ioctl
+};