linux/drivers/mtd/ubi/block.c
Linus Torvalds 02201e3f1b Minor merge needed, due to function move.
Main excitement here is Peter Zijlstra's lockless rbtree optimization to
 speed module address lookup.  He found some abusers of the module lock
 doing that too.
 
 A little bit of parameter work here too; including Dan Streetman's breaking
 up the big param mutex so writing a parameter can load another module (yeah,
 really).  Unfortunately that broke the usual suspects, !CONFIG_MODULES and
 !CONFIG_SYSFS, so those fixes were appended too.
 
 Cheers,
 Rusty.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQIcBAABAgAGBQJVkgKHAAoJENkgDmzRrbjxQpwQAJVmBN6jF3SnwbQXv9vRixjH
 58V33sb1G1RW+kXxQ3/e8jLX/4VaN479CufruXQp+IJWXsN/CH0lbC3k8m7u50d7
 b1Zeqd/Yrh79rkc11b0X1698uGCSMlzz+V54Z0QOTEEX+nSu2ZZvccFS4UaHkn3z
 rqDo00lb7rxQz8U25qro2OZrG6D3ub2q20TkWUB8EO4AOHkPn8KWP2r429Axrr0K
 wlDWDTTt8/IsvPbuPf3T15RAhq1avkMXWn9nDXDjyWbpLfTn8NFnWmtesgY7Jl4t
 GjbXC5WYekX3w2ZDB9KaT/DAMQ1a7RbMXNSz4RX4VbzDl+yYeSLmIh2G9fZb1PbB
 PsIxrOgy4BquOWsJPm+zeFPSC3q9Cfu219L4AmxSjiZxC3dlosg5rIB892Mjoyv4
 qxmg6oiqtc4Jxv+Gl9lRFVOqyHZrTC5IJ+xgfv1EyP6kKMUKLlDZtxZAuQxpUyxR
 HZLq220RYnYSvkWauikq4M8fqFM8bdt6hLJnv7bVqllseROk9stCvjSiE3A9szH5
 OgtOfYV5GhOeb8pCZqJKlGDw+RoJ21jtNCgOr6DgkNKV9CX/kL/Puwv8gnA0B0eh
 dxCeB7f/gcLl7Cg3Z3gVVcGlgak6JWrLf5ITAJhBZ8Lv+AtL2DKmwEWS/iIMRmek
 tLdh/a9GiCitqS0bT7GE
 =tWPQ
 -----END PGP SIGNATURE-----

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "Main excitement here is Peter Zijlstra's lockless rbtree optimization
  to speed module address lookup.  He found some abusers of the module
  lock doing that too.

  A little bit of parameter work here too; including Dan Streetman's
  breaking up the big param mutex so writing a parameter can load
  another module (yeah, really).  Unfortunately that broke the usual
  suspects, !CONFIG_MODULES and !CONFIG_SYSFS, so those fixes were
  appended too"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (26 commits)
  modules: only use mod->param_lock if CONFIG_MODULES
  param: fix module param locks when !CONFIG_SYSFS.
  rcu: merge fix for Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()
  module: add per-module param_lock
  module: make perm const
  params: suppress unused variable error, warn once just in case code changes.
  modules: clarify CONFIG_MODULE_COMPRESS help, suggest 'N'.
  kernel/module.c: avoid ifdefs for sig_enforce declaration
  kernel/workqueue.c: remove ifdefs over wq_power_efficient
  kernel/params.c: export param_ops_bool_enable_only
  kernel/params.c: generalize bool_enable_only
  kernel/module.c: use generic module param operaters for sig_enforce
  kernel/params: constify struct kernel_param_ops uses
  sysfs: tightened sysfs permission checks
  module: Rework module_addr_{min,max}
  module: Use __module_address() for module_address_lookup()
  module: Make the mod_tree stuff conditional on PERF_EVENTS || TRACING
  module: Optimize __module_address() using a latched RB-tree
  rbtree: Implement generic latch_tree
  seqlock: Introduce raw_read_seqcount_latch()
  ...
2015-07-01 10:49:25 -07:00

682 lines
17 KiB
C

/*
* Copyright (c) 2014 Ezequiel Garcia
* Copyright (c) 2011 Free Electrons
*
* Driver parameter handling strongly based on drivers/mtd/ubi/build.c
* Copyright (c) International Business Machines Corp., 2006
* Copyright (c) Nokia Corporation, 2007
* Authors: Artem Bityutskiy, Frank Haverkamp
*
* 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, version 2.
*
* 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.
*/
/*
* Read-only block devices on top of UBI volumes
*
* A simple implementation to allow a block device to be layered on top of a
* UBI volume. The implementation is provided by creating a static 1-to-1
* mapping between the block device and the UBI volume.
*
* The addressed byte is obtained from the addressed block sector, which is
* mapped linearly into the corresponding LEB:
*
* LEB number = addressed byte / LEB size
*
* This feature is compiled in the UBI core, and adds a 'block' parameter
* to allow early creation of block devices on top of UBI volumes. Runtime
* block creation/removal for UBI volumes is provided through two UBI ioctls:
* UBI_IOCVOLCRBLK and UBI_IOCVOLRMBLK.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/mtd/ubi.h>
#include <linux/workqueue.h>
#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/hdreg.h>
#include <linux/scatterlist.h>
#include <linux/idr.h>
#include <asm/div64.h>
#include "ubi-media.h"
#include "ubi.h"
/* Maximum number of supported devices */
#define UBIBLOCK_MAX_DEVICES 32
/* Maximum length of the 'block=' parameter */
#define UBIBLOCK_PARAM_LEN 63
/* Maximum number of comma-separated items in the 'block=' parameter */
#define UBIBLOCK_PARAM_COUNT 2
struct ubiblock_param {
int ubi_num;
int vol_id;
char name[UBIBLOCK_PARAM_LEN+1];
};
struct ubiblock_pdu {
struct work_struct work;
struct ubi_sgl usgl;
};
/* Numbers of elements set in the @ubiblock_param array */
static int ubiblock_devs __initdata;
/* MTD devices specification parameters */
static struct ubiblock_param ubiblock_param[UBIBLOCK_MAX_DEVICES] __initdata;
struct ubiblock {
struct ubi_volume_desc *desc;
int ubi_num;
int vol_id;
int refcnt;
int leb_size;
struct gendisk *gd;
struct request_queue *rq;
struct workqueue_struct *wq;
struct mutex dev_mutex;
struct list_head list;
struct blk_mq_tag_set tag_set;
};
/* Linked list of all ubiblock instances */
static LIST_HEAD(ubiblock_devices);
static DEFINE_MUTEX(devices_mutex);
static int ubiblock_major;
static int __init ubiblock_set_param(const char *val,
const struct kernel_param *kp)
{
int i, ret;
size_t len;
struct ubiblock_param *param;
char buf[UBIBLOCK_PARAM_LEN];
char *pbuf = &buf[0];
char *tokens[UBIBLOCK_PARAM_COUNT];
if (!val)
return -EINVAL;
len = strnlen(val, UBIBLOCK_PARAM_LEN);
if (len == 0) {
pr_warn("UBI: block: empty 'block=' parameter - ignored\n");
return 0;
}
if (len == UBIBLOCK_PARAM_LEN) {
pr_err("UBI: block: parameter \"%s\" is too long, max. is %d\n",
val, UBIBLOCK_PARAM_LEN);
return -EINVAL;
}
strcpy(buf, val);
/* Get rid of the final newline */
if (buf[len - 1] == '\n')
buf[len - 1] = '\0';
for (i = 0; i < UBIBLOCK_PARAM_COUNT; i++)
tokens[i] = strsep(&pbuf, ",");
param = &ubiblock_param[ubiblock_devs];
if (tokens[1]) {
/* Two parameters: can be 'ubi, vol_id' or 'ubi, vol_name' */
ret = kstrtoint(tokens[0], 10, &param->ubi_num);
if (ret < 0)
return -EINVAL;
/* Second param can be a number or a name */
ret = kstrtoint(tokens[1], 10, &param->vol_id);
if (ret < 0) {
param->vol_id = -1;
strcpy(param->name, tokens[1]);
}
} else {
/* One parameter: must be device path */
strcpy(param->name, tokens[0]);
param->ubi_num = -1;
param->vol_id = -1;
}
ubiblock_devs++;
return 0;
}
static const struct kernel_param_ops ubiblock_param_ops = {
.set = ubiblock_set_param,
};
module_param_cb(block, &ubiblock_param_ops, NULL, 0);
MODULE_PARM_DESC(block, "Attach block devices to UBI volumes. Parameter format: block=<path|dev,num|dev,name>.\n"
"Multiple \"block\" parameters may be specified.\n"
"UBI volumes may be specified by their number, name, or path to the device node.\n"
"Examples\n"
"Using the UBI volume path:\n"
"ubi.block=/dev/ubi0_0\n"
"Using the UBI device, and the volume name:\n"
"ubi.block=0,rootfs\n"
"Using both UBI device number and UBI volume number:\n"
"ubi.block=0,0\n");
static struct ubiblock *find_dev_nolock(int ubi_num, int vol_id)
{
struct ubiblock *dev;
list_for_each_entry(dev, &ubiblock_devices, list)
if (dev->ubi_num == ubi_num && dev->vol_id == vol_id)
return dev;
return NULL;
}
static int ubiblock_read(struct ubiblock_pdu *pdu)
{
int ret, leb, offset, bytes_left, to_read;
u64 pos;
struct request *req = blk_mq_rq_from_pdu(pdu);
struct ubiblock *dev = req->q->queuedata;
to_read = blk_rq_bytes(req);
pos = blk_rq_pos(req) << 9;
/* Get LEB:offset address to read from */
offset = do_div(pos, dev->leb_size);
leb = pos;
bytes_left = to_read;
while (bytes_left) {
/*
* We can only read one LEB at a time. Therefore if the read
* length is larger than one LEB size, we split the operation.
*/
if (offset + to_read > dev->leb_size)
to_read = dev->leb_size - offset;
ret = ubi_read_sg(dev->desc, leb, &pdu->usgl, offset, to_read);
if (ret < 0)
return ret;
bytes_left -= to_read;
to_read = bytes_left;
leb += 1;
offset = 0;
}
return 0;
}
static int ubiblock_open(struct block_device *bdev, fmode_t mode)
{
struct ubiblock *dev = bdev->bd_disk->private_data;
int ret;
mutex_lock(&dev->dev_mutex);
if (dev->refcnt > 0) {
/*
* The volume is already open, just increase the reference
* counter.
*/
goto out_done;
}
/*
* We want users to be aware they should only mount us as read-only.
* It's just a paranoid check, as write requests will get rejected
* in any case.
*/
if (mode & FMODE_WRITE) {
ret = -EPERM;
goto out_unlock;
}
dev->desc = ubi_open_volume(dev->ubi_num, dev->vol_id, UBI_READONLY);
if (IS_ERR(dev->desc)) {
dev_err(disk_to_dev(dev->gd), "failed to open ubi volume %d_%d",
dev->ubi_num, dev->vol_id);
ret = PTR_ERR(dev->desc);
dev->desc = NULL;
goto out_unlock;
}
out_done:
dev->refcnt++;
mutex_unlock(&dev->dev_mutex);
return 0;
out_unlock:
mutex_unlock(&dev->dev_mutex);
return ret;
}
static void ubiblock_release(struct gendisk *gd, fmode_t mode)
{
struct ubiblock *dev = gd->private_data;
mutex_lock(&dev->dev_mutex);
dev->refcnt--;
if (dev->refcnt == 0) {
ubi_close_volume(dev->desc);
dev->desc = NULL;
}
mutex_unlock(&dev->dev_mutex);
}
static int ubiblock_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
/* Some tools might require this information */
geo->heads = 1;
geo->cylinders = 1;
geo->sectors = get_capacity(bdev->bd_disk);
geo->start = 0;
return 0;
}
static const struct block_device_operations ubiblock_ops = {
.owner = THIS_MODULE,
.open = ubiblock_open,
.release = ubiblock_release,
.getgeo = ubiblock_getgeo,
};
static void ubiblock_do_work(struct work_struct *work)
{
int ret;
struct ubiblock_pdu *pdu = container_of(work, struct ubiblock_pdu, work);
struct request *req = blk_mq_rq_from_pdu(pdu);
blk_mq_start_request(req);
/*
* It is safe to ignore the return value of blk_rq_map_sg() because
* the number of sg entries is limited to UBI_MAX_SG_COUNT
* and ubi_read_sg() will check that limit.
*/
blk_rq_map_sg(req->q, req, pdu->usgl.sg);
ret = ubiblock_read(pdu);
rq_flush_dcache_pages(req);
blk_mq_end_request(req, ret);
}
static int ubiblock_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
struct request *req = bd->rq;
struct ubiblock *dev = hctx->queue->queuedata;
struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
if (req->cmd_type != REQ_TYPE_FS)
return BLK_MQ_RQ_QUEUE_ERROR;
if (rq_data_dir(req) != READ)
return BLK_MQ_RQ_QUEUE_ERROR; /* Write not implemented */
ubi_sgl_init(&pdu->usgl);
queue_work(dev->wq, &pdu->work);
return BLK_MQ_RQ_QUEUE_OK;
}
static int ubiblock_init_request(void *data, struct request *req,
unsigned int hctx_idx,
unsigned int request_idx,
unsigned int numa_node)
{
struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
sg_init_table(pdu->usgl.sg, UBI_MAX_SG_COUNT);
INIT_WORK(&pdu->work, ubiblock_do_work);
return 0;
}
static struct blk_mq_ops ubiblock_mq_ops = {
.queue_rq = ubiblock_queue_rq,
.init_request = ubiblock_init_request,
.map_queue = blk_mq_map_queue,
};
static DEFINE_IDR(ubiblock_minor_idr);
int ubiblock_create(struct ubi_volume_info *vi)
{
struct ubiblock *dev;
struct gendisk *gd;
u64 disk_capacity = vi->used_bytes >> 9;
int ret;
if ((sector_t)disk_capacity != disk_capacity)
return -EFBIG;
/* Check that the volume isn't already handled */
mutex_lock(&devices_mutex);
if (find_dev_nolock(vi->ubi_num, vi->vol_id)) {
mutex_unlock(&devices_mutex);
return -EEXIST;
}
mutex_unlock(&devices_mutex);
dev = kzalloc(sizeof(struct ubiblock), GFP_KERNEL);
if (!dev)
return -ENOMEM;
mutex_init(&dev->dev_mutex);
dev->ubi_num = vi->ubi_num;
dev->vol_id = vi->vol_id;
dev->leb_size = vi->usable_leb_size;
/* Initialize the gendisk of this ubiblock device */
gd = alloc_disk(1);
if (!gd) {
pr_err("UBI: block: alloc_disk failed");
ret = -ENODEV;
goto out_free_dev;
}
gd->fops = &ubiblock_ops;
gd->major = ubiblock_major;
gd->first_minor = idr_alloc(&ubiblock_minor_idr, dev, 0, 0, GFP_KERNEL);
if (gd->first_minor < 0) {
dev_err(disk_to_dev(gd),
"block: dynamic minor allocation failed");
ret = -ENODEV;
goto out_put_disk;
}
gd->private_data = dev;
sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
set_capacity(gd, disk_capacity);
dev->gd = gd;
dev->tag_set.ops = &ubiblock_mq_ops;
dev->tag_set.queue_depth = 64;
dev->tag_set.numa_node = NUMA_NO_NODE;
dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
dev->tag_set.cmd_size = sizeof(struct ubiblock_pdu);
dev->tag_set.driver_data = dev;
dev->tag_set.nr_hw_queues = 1;
ret = blk_mq_alloc_tag_set(&dev->tag_set);
if (ret) {
dev_err(disk_to_dev(dev->gd), "blk_mq_alloc_tag_set failed");
goto out_remove_minor;
}
dev->rq = blk_mq_init_queue(&dev->tag_set);
if (IS_ERR(dev->rq)) {
dev_err(disk_to_dev(gd), "blk_mq_init_queue failed");
ret = PTR_ERR(dev->rq);
goto out_free_tags;
}
blk_queue_max_segments(dev->rq, UBI_MAX_SG_COUNT);
dev->rq->queuedata = dev;
dev->gd->queue = dev->rq;
/*
* Create one workqueue per volume (per registered block device).
* Rembember workqueues are cheap, they're not threads.
*/
dev->wq = alloc_workqueue("%s", 0, 0, gd->disk_name);
if (!dev->wq) {
ret = -ENOMEM;
goto out_free_queue;
}
mutex_lock(&devices_mutex);
list_add_tail(&dev->list, &ubiblock_devices);
mutex_unlock(&devices_mutex);
/* Must be the last step: anyone can call file ops from now on */
add_disk(dev->gd);
dev_info(disk_to_dev(dev->gd), "created from ubi%d:%d(%s)",
dev->ubi_num, dev->vol_id, vi->name);
return 0;
out_free_queue:
blk_cleanup_queue(dev->rq);
out_free_tags:
blk_mq_free_tag_set(&dev->tag_set);
out_remove_minor:
idr_remove(&ubiblock_minor_idr, gd->first_minor);
out_put_disk:
put_disk(dev->gd);
out_free_dev:
kfree(dev);
return ret;
}
static void ubiblock_cleanup(struct ubiblock *dev)
{
/* Stop new requests to arrive */
del_gendisk(dev->gd);
/* Flush pending work */
destroy_workqueue(dev->wq);
/* Finally destroy the blk queue */
blk_cleanup_queue(dev->rq);
blk_mq_free_tag_set(&dev->tag_set);
dev_info(disk_to_dev(dev->gd), "released");
idr_remove(&ubiblock_minor_idr, dev->gd->first_minor);
put_disk(dev->gd);
}
int ubiblock_remove(struct ubi_volume_info *vi)
{
struct ubiblock *dev;
mutex_lock(&devices_mutex);
dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
if (!dev) {
mutex_unlock(&devices_mutex);
return -ENODEV;
}
/* Found a device, let's lock it so we can check if it's busy */
mutex_lock(&dev->dev_mutex);
if (dev->refcnt > 0) {
mutex_unlock(&dev->dev_mutex);
mutex_unlock(&devices_mutex);
return -EBUSY;
}
/* Remove from device list */
list_del(&dev->list);
mutex_unlock(&devices_mutex);
ubiblock_cleanup(dev);
mutex_unlock(&dev->dev_mutex);
kfree(dev);
return 0;
}
static int ubiblock_resize(struct ubi_volume_info *vi)
{
struct ubiblock *dev;
u64 disk_capacity = vi->used_bytes >> 9;
/*
* Need to lock the device list until we stop using the device,
* otherwise the device struct might get released in
* 'ubiblock_remove()'.
*/
mutex_lock(&devices_mutex);
dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
if (!dev) {
mutex_unlock(&devices_mutex);
return -ENODEV;
}
if ((sector_t)disk_capacity != disk_capacity) {
mutex_unlock(&devices_mutex);
dev_warn(disk_to_dev(dev->gd), "the volume is too big (%d LEBs), cannot resize",
vi->size);
return -EFBIG;
}
mutex_lock(&dev->dev_mutex);
if (get_capacity(dev->gd) != disk_capacity) {
set_capacity(dev->gd, disk_capacity);
dev_info(disk_to_dev(dev->gd), "resized to %lld bytes",
vi->used_bytes);
}
mutex_unlock(&dev->dev_mutex);
mutex_unlock(&devices_mutex);
return 0;
}
static int ubiblock_notify(struct notifier_block *nb,
unsigned long notification_type, void *ns_ptr)
{
struct ubi_notification *nt = ns_ptr;
switch (notification_type) {
case UBI_VOLUME_ADDED:
/*
* We want to enforce explicit block device creation for
* volumes, so when a volume is added we do nothing.
*/
break;
case UBI_VOLUME_REMOVED:
ubiblock_remove(&nt->vi);
break;
case UBI_VOLUME_RESIZED:
ubiblock_resize(&nt->vi);
break;
case UBI_VOLUME_UPDATED:
/*
* If the volume is static, a content update might mean the
* size (i.e. used_bytes) was also changed.
*/
if (nt->vi.vol_type == UBI_STATIC_VOLUME)
ubiblock_resize(&nt->vi);
break;
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block ubiblock_notifier = {
.notifier_call = ubiblock_notify,
};
static struct ubi_volume_desc * __init
open_volume_desc(const char *name, int ubi_num, int vol_id)
{
if (ubi_num == -1)
/* No ubi num, name must be a vol device path */
return ubi_open_volume_path(name, UBI_READONLY);
else if (vol_id == -1)
/* No vol_id, must be vol_name */
return ubi_open_volume_nm(ubi_num, name, UBI_READONLY);
else
return ubi_open_volume(ubi_num, vol_id, UBI_READONLY);
}
static void __init ubiblock_create_from_param(void)
{
int i, ret = 0;
struct ubiblock_param *p;
struct ubi_volume_desc *desc;
struct ubi_volume_info vi;
/*
* If there is an error creating one of the ubiblocks, continue on to
* create the following ubiblocks. This helps in a circumstance where
* the kernel command-line specifies multiple block devices and some
* may be broken, but we still want the working ones to come up.
*/
for (i = 0; i < ubiblock_devs; i++) {
p = &ubiblock_param[i];
desc = open_volume_desc(p->name, p->ubi_num, p->vol_id);
if (IS_ERR(desc)) {
pr_err(
"UBI: block: can't open volume on ubi%d_%d, err=%ld",
p->ubi_num, p->vol_id, PTR_ERR(desc));
continue;
}
ubi_get_volume_info(desc, &vi);
ubi_close_volume(desc);
ret = ubiblock_create(&vi);
if (ret) {
pr_err(
"UBI: block: can't add '%s' volume on ubi%d_%d, err=%d",
vi.name, p->ubi_num, p->vol_id, ret);
continue;
}
}
}
static void ubiblock_remove_all(void)
{
struct ubiblock *next;
struct ubiblock *dev;
list_for_each_entry_safe(dev, next, &ubiblock_devices, list) {
/* The module is being forcefully removed */
WARN_ON(dev->desc);
/* Remove from device list */
list_del(&dev->list);
ubiblock_cleanup(dev);
kfree(dev);
}
}
int __init ubiblock_init(void)
{
int ret;
ubiblock_major = register_blkdev(0, "ubiblock");
if (ubiblock_major < 0)
return ubiblock_major;
/*
* Attach block devices from 'block=' module param.
* Even if one block device in the param list fails to come up,
* still allow the module to load and leave any others up.
*/
ubiblock_create_from_param();
/*
* Block devices are only created upon user requests, so we ignore
* existing volumes.
*/
ret = ubi_register_volume_notifier(&ubiblock_notifier, 1);
if (ret)
goto err_unreg;
return 0;
err_unreg:
unregister_blkdev(ubiblock_major, "ubiblock");
ubiblock_remove_all();
return ret;
}
void __exit ubiblock_exit(void)
{
ubi_unregister_volume_notifier(&ubiblock_notifier);
ubiblock_remove_all();
unregister_blkdev(ubiblock_major, "ubiblock");
}