linux_dsm_epyc7002/drivers/mtd/devices/block2mtd.c
Kirill A. Shutemov 09cbfeaf1a mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-04 10:41:08 -07:00

502 lines
11 KiB
C

/*
* block2mtd.c - create an mtd from a block device
*
* Copyright (C) 2001,2002 Simon Evans <spse@secret.org.uk>
* Copyright (C) 2004-2006 Joern Engel <joern@wh.fh-wedel.de>
*
* Licence: GPL
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
/*
* When the first attempt at device initialization fails, we may need to
* wait a little bit and retry. This timeout, by default 3 seconds, gives
* device time to start up. Required on BCM2708 and a few other chipsets.
*/
#define MTD_DEFAULT_TIMEOUT 3
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/bio.h>
#include <linux/pagemap.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/mtd/mtd.h>
#include <linux/mutex.h>
#include <linux/mount.h>
#include <linux/slab.h>
#include <linux/major.h>
/* Info for the block device */
struct block2mtd_dev {
struct list_head list;
struct block_device *blkdev;
struct mtd_info mtd;
struct mutex write_mutex;
};
/* Static info about the MTD, used in cleanup_module */
static LIST_HEAD(blkmtd_device_list);
static struct page *page_read(struct address_space *mapping, int index)
{
return read_mapping_page(mapping, index, NULL);
}
/* erase a specified part of the device */
static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
{
struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
struct page *page;
int index = to >> PAGE_SHIFT; // page index
int pages = len >> PAGE_SHIFT;
u_long *p;
u_long *max;
while (pages) {
page = page_read(mapping, index);
if (IS_ERR(page))
return PTR_ERR(page);
max = page_address(page) + PAGE_SIZE;
for (p=page_address(page); p<max; p++)
if (*p != -1UL) {
lock_page(page);
memset(page_address(page), 0xff, PAGE_SIZE);
set_page_dirty(page);
unlock_page(page);
balance_dirty_pages_ratelimited(mapping);
break;
}
put_page(page);
pages--;
index++;
}
return 0;
}
static int block2mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
{
struct block2mtd_dev *dev = mtd->priv;
size_t from = instr->addr;
size_t len = instr->len;
int err;
instr->state = MTD_ERASING;
mutex_lock(&dev->write_mutex);
err = _block2mtd_erase(dev, from, len);
mutex_unlock(&dev->write_mutex);
if (err) {
pr_err("erase failed err = %d\n", err);
instr->state = MTD_ERASE_FAILED;
} else
instr->state = MTD_ERASE_DONE;
mtd_erase_callback(instr);
return err;
}
static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
struct block2mtd_dev *dev = mtd->priv;
struct page *page;
int index = from >> PAGE_SHIFT;
int offset = from & (PAGE_SIZE-1);
int cpylen;
while (len) {
if ((offset + len) > PAGE_SIZE)
cpylen = PAGE_SIZE - offset; // multiple pages
else
cpylen = len; // this page
len = len - cpylen;
page = page_read(dev->blkdev->bd_inode->i_mapping, index);
if (IS_ERR(page))
return PTR_ERR(page);
memcpy(buf, page_address(page) + offset, cpylen);
put_page(page);
if (retlen)
*retlen += cpylen;
buf += cpylen;
offset = 0;
index++;
}
return 0;
}
/* write data to the underlying device */
static int _block2mtd_write(struct block2mtd_dev *dev, const u_char *buf,
loff_t to, size_t len, size_t *retlen)
{
struct page *page;
struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
int index = to >> PAGE_SHIFT; // page index
int offset = to & ~PAGE_MASK; // page offset
int cpylen;
while (len) {
if ((offset+len) > PAGE_SIZE)
cpylen = PAGE_SIZE - offset; // multiple pages
else
cpylen = len; // this page
len = len - cpylen;
page = page_read(mapping, index);
if (IS_ERR(page))
return PTR_ERR(page);
if (memcmp(page_address(page)+offset, buf, cpylen)) {
lock_page(page);
memcpy(page_address(page) + offset, buf, cpylen);
set_page_dirty(page);
unlock_page(page);
balance_dirty_pages_ratelimited(mapping);
}
put_page(page);
if (retlen)
*retlen += cpylen;
buf += cpylen;
offset = 0;
index++;
}
return 0;
}
static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, const u_char *buf)
{
struct block2mtd_dev *dev = mtd->priv;
int err;
mutex_lock(&dev->write_mutex);
err = _block2mtd_write(dev, buf, to, len, retlen);
mutex_unlock(&dev->write_mutex);
if (err > 0)
err = 0;
return err;
}
/* sync the device - wait until the write queue is empty */
static void block2mtd_sync(struct mtd_info *mtd)
{
struct block2mtd_dev *dev = mtd->priv;
sync_blockdev(dev->blkdev);
return;
}
static void block2mtd_free_device(struct block2mtd_dev *dev)
{
if (!dev)
return;
kfree(dev->mtd.name);
if (dev->blkdev) {
invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping,
0, -1);
blkdev_put(dev->blkdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
}
kfree(dev);
}
static struct block2mtd_dev *add_device(char *devname, int erase_size,
int timeout)
{
#ifndef MODULE
int i;
#endif
const fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL;
struct block_device *bdev = ERR_PTR(-ENODEV);
struct block2mtd_dev *dev;
char *name;
if (!devname)
return NULL;
dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL);
if (!dev)
return NULL;
/* Get a handle on the device */
bdev = blkdev_get_by_path(devname, mode, dev);
#ifndef MODULE
/*
* We might not have the root device mounted at this point.
* Try to resolve the device name by other means.
*/
for (i = 0; IS_ERR(bdev) && i <= timeout; i++) {
dev_t devt;
if (i)
/*
* Calling wait_for_device_probe in the first loop
* was not enough, sleep for a bit in subsequent
* go-arounds.
*/
msleep(1000);
wait_for_device_probe();
devt = name_to_dev_t(devname);
if (!devt)
continue;
bdev = blkdev_get_by_dev(devt, mode, dev);
}
#endif
if (IS_ERR(bdev)) {
pr_err("error: cannot open device %s\n", devname);
goto err_free_block2mtd;
}
dev->blkdev = bdev;
if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
pr_err("attempting to use an MTD device as a block device\n");
goto err_free_block2mtd;
}
if ((long)dev->blkdev->bd_inode->i_size % erase_size) {
pr_err("erasesize must be a divisor of device size\n");
goto err_free_block2mtd;
}
mutex_init(&dev->write_mutex);
/* Setup the MTD structure */
/* make the name contain the block device in */
name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);
if (!name)
goto err_destroy_mutex;
dev->mtd.name = name;
dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK;
dev->mtd.erasesize = erase_size;
dev->mtd.writesize = 1;
dev->mtd.writebufsize = PAGE_SIZE;
dev->mtd.type = MTD_RAM;
dev->mtd.flags = MTD_CAP_RAM;
dev->mtd._erase = block2mtd_erase;
dev->mtd._write = block2mtd_write;
dev->mtd._sync = block2mtd_sync;
dev->mtd._read = block2mtd_read;
dev->mtd.priv = dev;
dev->mtd.owner = THIS_MODULE;
if (mtd_device_register(&dev->mtd, NULL, 0)) {
/* Device didn't get added, so free the entry */
goto err_destroy_mutex;
}
list_add(&dev->list, &blkmtd_device_list);
pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n",
dev->mtd.index,
dev->mtd.name + strlen("block2mtd: "),
dev->mtd.erasesize >> 10, dev->mtd.erasesize);
return dev;
err_destroy_mutex:
mutex_destroy(&dev->write_mutex);
err_free_block2mtd:
block2mtd_free_device(dev);
return NULL;
}
/* This function works similar to reguler strtoul. In addition, it
* allows some suffixes for a more human-readable number format:
* ki, Ki, kiB, KiB - multiply result with 1024
* Mi, MiB - multiply result with 1024^2
* Gi, GiB - multiply result with 1024^3
*/
static int ustrtoul(const char *cp, char **endp, unsigned int base)
{
unsigned long result = simple_strtoul(cp, endp, base);
switch (**endp) {
case 'G' :
result *= 1024;
case 'M':
result *= 1024;
case 'K':
case 'k':
result *= 1024;
/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
if ((*endp)[1] == 'i') {
if ((*endp)[2] == 'B')
(*endp) += 3;
else
(*endp) += 2;
}
}
return result;
}
static int parse_num(size_t *num, const char *token)
{
char *endp;
size_t n;
n = (size_t) ustrtoul(token, &endp, 0);
if (*endp)
return -EINVAL;
*num = n;
return 0;
}
static inline void kill_final_newline(char *str)
{
char *newline = strrchr(str, '\n');
if (newline && !newline[1])
*newline = 0;
}
#ifndef MODULE
static int block2mtd_init_called = 0;
/* 80 for device, 12 for erase size */
static char block2mtd_paramline[80 + 12];
#endif
static int block2mtd_setup2(const char *val)
{
/* 80 for device, 12 for erase size, 80 for name, 8 for timeout */
char buf[80 + 12 + 80 + 8];
char *str = buf;
char *token[2];
char *name;
size_t erase_size = PAGE_SIZE;
unsigned long timeout = MTD_DEFAULT_TIMEOUT;
int i, ret;
if (strnlen(val, sizeof(buf)) >= sizeof(buf)) {
pr_err("parameter too long\n");
return 0;
}
strcpy(str, val);
kill_final_newline(str);
for (i = 0; i < 2; i++)
token[i] = strsep(&str, ",");
if (str) {
pr_err("too many arguments\n");
return 0;
}
if (!token[0]) {
pr_err("no argument\n");
return 0;
}
name = token[0];
if (strlen(name) + 1 > 80) {
pr_err("device name too long\n");
return 0;
}
if (token[1]) {
ret = parse_num(&erase_size, token[1]);
if (ret) {
pr_err("illegal erase size\n");
return 0;
}
}
add_device(name, erase_size, timeout);
return 0;
}
static int block2mtd_setup(const char *val, struct kernel_param *kp)
{
#ifdef MODULE
return block2mtd_setup2(val);
#else
/* If more parameters are later passed in via
/sys/module/block2mtd/parameters/block2mtd
and block2mtd_init() has already been called,
we can parse the argument now. */
if (block2mtd_init_called)
return block2mtd_setup2(val);
/* During early boot stage, we only save the parameters
here. We must parse them later: if the param passed
from kernel boot command line, block2mtd_setup() is
called so early that it is not possible to resolve
the device (even kmalloc() fails). Deter that work to
block2mtd_setup2(). */
strlcpy(block2mtd_paramline, val, sizeof(block2mtd_paramline));
return 0;
#endif
}
module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200);
MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,<erasesize>]\"");
static int __init block2mtd_init(void)
{
int ret = 0;
#ifndef MODULE
if (strlen(block2mtd_paramline))
ret = block2mtd_setup2(block2mtd_paramline);
block2mtd_init_called = 1;
#endif
return ret;
}
static void block2mtd_exit(void)
{
struct list_head *pos, *next;
/* Remove the MTD devices */
list_for_each_safe(pos, next, &blkmtd_device_list) {
struct block2mtd_dev *dev = list_entry(pos, typeof(*dev), list);
block2mtd_sync(&dev->mtd);
mtd_device_unregister(&dev->mtd);
mutex_destroy(&dev->write_mutex);
pr_info("mtd%d: [%s] removed\n",
dev->mtd.index,
dev->mtd.name + strlen("block2mtd: "));
list_del(&dev->list);
block2mtd_free_device(dev);
}
}
late_initcall(block2mtd_init);
module_exit(block2mtd_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Joern Engel <joern@lazybastard.org>");
MODULE_DESCRIPTION("Emulate an MTD using a block device");