/*
* $Id: blkmtd.c,v 1.17 2003/01/24 13:00:24 dwmw2 Exp $
*
* blkmtd.c - use a block device as a fake MTD
*
* Author: Simon Evans <spse@secret.org.uk>
*
* Copyright (C) 2001,2002 Simon Evans
*
* Licence: GPL
*
* How it works:
* The driver uses raw/io to read/write the device and the page
* cache to cache access. Writes update the page cache with the
* new data and mark it dirty and add the page into a kiobuf.
* When the kiobuf becomes full or the next extry is to an earlier
* block in the kiobuf then it is flushed to disk. This allows
* writes to remained ordered and gives a small and simple outgoing
* write cache.
*
* It can be loaded Read-Only to prevent erases and writes to the
* medium.
*
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/iobuf.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/list.h>
#include <linux/mtd/mtd.h>
#ifdef CONFIG_MTD_DEBUG
#ifdef CONFIG_PROC_FS
# include <linux/proc_fs.h>
# define BLKMTD_PROC_DEBUG
static struct proc_dir_entry *blkmtd_proc;
#endif
#endif
#define err(format, arg...) printk(KERN_ERR "blkmtd: " format "\n" , ## arg)
#define info(format, arg...) printk(KERN_INFO "blkmtd: " format "\n" , ## arg)
#define warn(format, arg...) printk(KERN_WARNING "blkmtd: " format "\n" , ## arg)
#define crit(format, arg...) printk(KERN_CRIT "blkmtd: " format "\n" , ## arg)
/* Default erase size in KiB, always make it a multiple of PAGE_SIZE */
#define CONFIG_MTD_BLKDEV_ERASESIZE (128 << 10) /* 128KiB */
#define VERSION "1.10"
/* Info for the block device */
struct blkmtd_dev {
struct list_head list;
struct block_device *binding;
struct mtd_info mtd_info;
struct kiobuf *rd_buf, *wr_buf;
long iobuf_locks;
struct semaphore wrbuf_mutex;
};
/* Static info about the MTD, used in cleanup_module */
static LIST_HEAD(blkmtd_device_list);
static void blkmtd_sync(struct mtd_info *mtd);
#define MAX_DEVICES 4
/* Module parameters passed by insmod/modprobe */
char *device[MAX_DEVICES]; /* the block device to use */
int erasesz[MAX_DEVICES]; /* optional default erase size */
int ro[MAX_DEVICES]; /* optional read only flag */
int sync;
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Simon Evans <spse@secret.org.uk>");
MODULE_DESCRIPTION("Emulate an MTD using a block device");
MODULE_PARM(device, "1-4s");
MODULE_PARM_DESC(device, "block device to use");
MODULE_PARM(erasesz, "1-4i");
MODULE_PARM_DESC(erasesz, "optional erase size to use in KiB. eg 4=4KiB.");
MODULE_PARM(ro, "1-4i");
MODULE_PARM_DESC(ro, "1=Read only, writes and erases cause errors");
MODULE_PARM(sync, "i");
MODULE_PARM_DESC(sync, "1=Synchronous writes");
/**
* read_pages - read in pages via the page cache
* @dev: device to read from
* @pagenrs: list of page numbers wanted
* @pagelst: storage for struce page * pointers
* @pages: count of pages wanted
*
* Read pages, getting them from the page cache if available
* else reading them in from disk if not. pagelst must be preallocated
* to hold the page count.
*/
static int read_pages(struct blkmtd_dev *dev, int pagenrs[], struct page **pagelst, int pages)
{
kdev_t kdev;
struct page *page;
int cnt = 0;
struct kiobuf *iobuf;
int err = 0;
if(!dev) {
err("read_pages: PANIC dev == NULL");
return -EIO;
}
kdev = to_kdev_t(dev->binding->bd_dev);
DEBUG(2, "read_pages: reading %d pages\n", pages);
if(test_and_set_bit(0, &dev->iobuf_locks)) {
err = alloc_kiovec(1, &iobuf);
if (err) {
crit("cant allocate kiobuf");
return -ENOMEM;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,4)
iobuf->blocks = kmalloc(KIO_MAX_SECTORS * sizeof(unsigned long), GFP_KERNEL);
if(iobuf->blocks == NULL) {
crit("cant allocate iobuf blocks");
free_kiovec(1, &iobuf);
return -ENOMEM;
}
#endif
} else {
iobuf = dev->rd_buf;
}
iobuf->nr_pages = 0;
iobuf->length = 0;
iobuf->offset = 0;
iobuf->locked = 1;
for(cnt = 0; cnt < pages; cnt++) {
page = grab_cache_page(dev->binding->bd_inode->i_mapping, pagenrs[cnt]);
pagelst[cnt] = page;
if(!PageUptodate(page)) {
iobuf->blocks[iobuf->nr_pages] = pagenrs[cnt];
iobuf->maplist[iobuf->nr_pages++] = page;
}
}
if(iobuf->nr_pages) {
iobuf->length = iobuf->nr_pages << PAGE_SHIFT;
err = brw_kiovec(READ, 1, &iobuf, kdev, iobuf->blocks, PAGE_SIZE);
DEBUG(3, "blkmtd: read_pages: finished, err = %d\n", err);
if(err < 0) {
while(pages--) {
ClearPageUptodate(pagelst[pages]);
unlock_page(pagelst[pages]);
page_cache_release(pagelst[pages]);
}
} else {
while(iobuf->nr_pages--) {
SetPageUptodate(iobuf->maplist[iobuf->nr_pages]);
}
err = 0;
}
}
if(iobuf != dev->rd_buf) {
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,4)
kfree(iobuf->blocks);
#endif
free_kiovec(1, &iobuf);
} else {
clear_bit(0, &dev->iobuf_locks);
}
DEBUG(2, "read_pages: done, err = %d\n", err);
return err;
}
/**
* commit_pages - commit pages in the writeout kiobuf to disk
* @dev: device to write to
*
* If the current dev has pages in the dev->wr_buf kiobuf,
* they are written to disk using brw_kiovec()
*/
static int commit_pages(struct blkmtd_dev *dev)
{
struct kiobuf *iobuf = dev->wr_buf;
kdev_t kdev = to_kdev_t(dev->binding->bd_dev);
int err = 0;
iobuf->length = iobuf->nr_pages << PAGE_SHIFT;
iobuf->locked = 1;
if(iobuf->length) {
int i;
DEBUG(2, "blkmtd: commit_pages: nrpages = %d\n", iobuf->nr_pages);
/* Check all the pages are dirty and lock them */
for(i = 0; i < iobuf->nr_pages; i++) {
struct page *page = iobuf->maplist[i];
BUG_ON(!PageDirty(page));
lock_page(page);
}
err = brw_kiovec(WRITE, 1, &iobuf, kdev, iobuf->blocks, PAGE_SIZE);
DEBUG(3, "commit_write: committed %d pages err = %d\n", iobuf->nr_pages, err);
while(iobuf->nr_pages) {
struct page *page = iobuf->maplist[--iobuf->nr_pages];
ClearPageDirty(page);
SetPageUptodate(page);
unlock_page(page);
page_cache_release(page);
}
}
DEBUG(2, "blkmtd: sync: end, err = %d\n", err);
iobuf->offset = 0;
iobuf->nr_pages = 0;
iobuf->length = 0;
return err;
}
/**
* write_pages - write block of data to device via the page cache
* @dev: device to write to
* @buf: data source or NULL if erase (output is set to 0xff)
* @to: offset into output device
* @len: amount to data to write
* @retlen: amount of data written
*
* Grab pages from the page cache and fill them with the source data.
* Non page aligned start and end result in a readin of the page and
* part of the page being modified. Pages are added to the wr_buf kiobuf
* until this becomes full or the next page written to has a lower pagenr
* then the current max pagenr in the kiobuf.
*/
static int write_pages(struct blkmtd_dev *dev, const u_char *buf, loff_t to,
size_t len, int *retlen)
{
int pagenr, offset;
size_t start_len = 0, end_len;
int pagecnt = 0;
struct kiobuf *iobuf = dev->wr_buf;
int err = 0;
struct page *pagelst[2];
int pagenrs[2];
int readpages = 0;
int ignorepage = -1;
pagenr = to >> PAGE_SHIFT;
offset = to & ~PAGE_MASK;
DEBUG(2, "blkmtd: write_pages: buf = %p to = %ld len = %d pagenr = %d offset = %d\n",
buf, (long)to, len, pagenr, offset);
*retlen = 0;
/* see if we have to do a partial write at the start */
if(offset) {
start_len = ((offset + len) > PAGE_SIZE) ? PAGE_SIZE - offset : len;
len -= start_len;
}
/* calculate the length of the other two regions */
end_len = len & ~PAGE_MASK;
len -= end_len;
if(start_len) {
pagenrs[0] = pagenr;
readpages++;
pagecnt++;
}
if(len)
pagecnt += len >> PAGE_SHIFT;
if(end_len) {
pagenrs[readpages] = pagenr + pagecnt;
readpages++;
pagecnt++;
}
DEBUG(3, "blkmtd: write: start_len = %d len = %d end_len = %d pagecnt = %d\n",
start_len, len, end_len, pagecnt);
down(&dev->wrbuf_mutex);
if(iobuf->nr_pages && ((pagenr <= iobuf->blocks[iobuf->nr_pages-1])
|| (iobuf->nr_pages + pagecnt) >= KIO_STATIC_PAGES)) {
if((pagenr == iobuf->blocks[iobuf->nr_pages-1])
&& ((iobuf->nr_pages + pagecnt) < KIO_STATIC_PAGES)) {
iobuf->nr_pages--;
ignorepage = pagenr;
} else {
DEBUG(3, "blkmtd: doing writeout pagenr = %d max_pagenr = %ld pagecnt = %d idx = %d\n",
pagenr, iobuf->blocks[iobuf->nr_pages-1],
pagecnt, iobuf->nr_pages);
commit_pages(dev);
}
}
if(readpages) {
err = read_pages(dev, pagenrs, pagelst, readpages);
if(err < 0)
goto readin_err;
}
if(start_len) {
/* do partial start region */
struct page *page;
DEBUG(3, "blkmtd: write: doing partial start, page = %d len = %d offset = %d\n",
pagenr, start_len, offset);
page = pagelst[0];
BUG_ON(!buf);
if(PageDirty(page) && pagenr != ignorepage) {
err("to = %lld start_len = %d len = %d end_len = %d pagenr = %d ignorepage = %d\n",
to, start_len, len, end_len, pagenr, ignorepage);
BUG();
}
memcpy(page_address(page)+offset, buf, start_len);
SetPageDirty(page);
SetPageUptodate(page);
unlock_page(page);
buf += start_len;
*retlen = start_len;
err = 0;
iobuf->blocks[iobuf->nr_pages] = pagenr++;
iobuf->maplist[iobuf->nr_pages] = page;
iobuf->nr_pages++;
}
/* Now do the main loop to a page aligned, n page sized output */
if(len) {
int pagesc = len >> PAGE_SHIFT;
DEBUG(3, "blkmtd: write: whole pages start = %d, count = %d\n",
pagenr, pagesc);
while(pagesc) {
struct page *page;
/* see if page is in the page cache */
DEBUG(3, "blkmtd: write: grabbing page %d from page cache\n", pagenr);
page = grab_cache_page(dev->binding->bd_inode->i_mapping, pagenr);
if(PageDirty(page) && pagenr != ignorepage) {
BUG();
}
if(!page) {
warn("write: cant grab cache page %d", pagenr);
err = -ENOMEM;
goto write_err;
}
if(!buf) {
memset(page_address(page), 0xff, PAGE_SIZE);
} else {
memcpy(page_address(page), buf, PAGE_SIZE);
buf += PAGE_SIZE;
}
iobuf->blocks[iobuf->nr_pages] = pagenr++;
iobuf->maplist[iobuf->nr_pages] = page;
iobuf->nr_pages++;
SetPageDirty(page);
SetPageUptodate(page);
unlock_page(page);
pagesc--;
*retlen += PAGE_SIZE;
}
}
if(end_len) {
/* do the third region */
struct page *page;
DEBUG(3, "blkmtd: write: doing partial end, page = %d len = %d\n",
pagenr, end_len);
page = pagelst[readpages-1];
BUG_ON(!buf);
if(PageDirty(page) && pagenr != ignorepage) {
err("to = %lld start_len = %d len = %d end_len = %d pagenr = %d ignorepage = %d\n",
to, start_len, len, end_len, pagenr, ignorepage);
BUG();
}
memcpy(page_address(page), buf, end_len);
SetPageDirty(page);
SetPageUptodate(page);
unlock_page(page);
DEBUG(3, "blkmtd: write: writing out partial end\n");
*retlen += end_len;
err = 0;
iobuf->blocks[iobuf->nr_pages] = pagenr;
iobuf->maplist[iobuf->nr_pages] = page;
iobuf->nr_pages++;
}
DEBUG(2, "blkmtd: write: end, retlen = %d, err = %d\n", *retlen, err);
if(sync) {
write_err:
commit_pages(dev);
}
readin_err:
up(&dev->wrbuf_mutex);
return err;
}
/* erase a specified part of the device */
static int blkmtd_erase(struct mtd_info *mtd, struct erase_info *instr)
{
struct blkmtd_dev *dev = mtd->priv;
struct mtd_erase_region_info *einfo = mtd->eraseregions;
int numregions = mtd->numeraseregions;
size_t from;
u_long len;
int err = -EIO;
int retlen;
/* check readonly */
if(!dev->wr_buf) {
err("error: mtd%d trying to erase readonly device %s",
mtd->index, mtd->name);
instr->state = MTD_ERASE_FAILED;
goto erase_callback;
}
instr->state = MTD_ERASING;
from = instr->addr;
len = instr->len;
/* check erase region has valid start and length */
DEBUG(2, "blkmtd: erase: dev = `%s' from = 0x%x len = 0x%lx\n",
bdevname(dev->binding->bd_dev), from, len);
while(numregions) {
DEBUG(3, "blkmtd: checking erase region = 0x%08X size = 0x%X num = 0x%x\n",
einfo->offset, einfo->erasesize, einfo->numblocks);
if(from >= einfo->offset
&& from < einfo->offset + (einfo->erasesize * einfo->numblocks)) {
if(len == einfo->erasesize
&& ( (from - einfo->offset) % einfo->erasesize == 0))
break;
}
numregions--;
einfo++;
}
if(!numregions) {
/* Not a valid erase block */
err("erase: invalid erase request 0x%lX @ 0x%08X", len, from);
instr->state = MTD_ERASE_FAILED;
err = -EIO;
}
if(instr->state != MTD_ERASE_FAILED) {
/* do the erase */
DEBUG(3, "Doing erase from = %d len = %ld\n", from, len);
err = write_pages(dev, NULL, from, len, &retlen);
if(err < 0) {
err("erase failed err = %d", err);
instr->state = MTD_ERASE_FAILED;
} else {
instr->state = MTD_ERASE_DONE;
err = 0;
}
}
DEBUG(3, "blkmtd: erase: checking callback\n");
erase_callback:
if (instr->callback) {
(*(instr->callback))(instr);
}
DEBUG(2, "blkmtd: erase: finished (err = %d)\n", err);
return err;
}
/* read a range of the data via the page cache */
static int blkmtd_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
struct blkmtd_dev *dev = mtd->priv;
int err = 0;
int offset;
int pagenr, pages;
struct page **pagelst;
int *pagenrs;
int i;
*retlen = 0;
DEBUG(2, "blkmtd: read: dev = `%s' from = %ld len = %d buf = %p\n",
bdevname(dev->binding->bd_dev), (long int)from, len, buf);
pagenr = from >> PAGE_SHIFT;
offset = from - (pagenr << PAGE_SHIFT);
pages = (offset+len+PAGE_SIZE-1) >> PAGE_SHIFT;
DEBUG(3, "blkmtd: read: pagenr = %d offset = %d, pages = %d\n",
pagenr, offset, pages);
pagelst = kmalloc(sizeof(struct page *) * pages, GFP_KERNEL);
if(!pagelst)
return -ENOMEM;
pagenrs = kmalloc(sizeof(int) * pages, GFP_KERNEL);
if(!pagenrs) {
kfree(pagelst);
return -ENOMEM;
}
for(i = 0; i < pages; i++)
pagenrs[i] = pagenr+i;
err = read_pages(dev, pagenrs, pagelst, pages);
if(err)
goto readerr;
pagenr = 0;
while(pages) {
struct page *page;
int cpylen;
DEBUG(3, "blkmtd: read: looking for page: %d\n", pagenr);
page = pagelst[pagenr];
cpylen = (PAGE_SIZE > len) ? len : PAGE_SIZE;
if(offset+cpylen > PAGE_SIZE)
cpylen = PAGE_SIZE-offset;
memcpy(buf + *retlen, page_address(page) + offset, cpylen);
offset = 0;
len -= cpylen;
*retlen += cpylen;
pagenr++;
pages--;
unlock_page(page);
if(!PageDirty(page))
page_cache_release(page);
}
readerr:
kfree(pagelst);
kfree(pagenrs);
DEBUG(2, "blkmtd: end read: retlen = %d, err = %d\n", *retlen, err);
return err;
}
/* write data to the underlying device */
static int blkmtd_write(struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, const u_char *buf)
{
struct blkmtd_dev *dev = mtd->priv;
int err;
*retlen = 0;
if(!len)
return 0;
DEBUG(2, "blkmtd: write: dev = `%s' to = %ld len = %d buf = %p\n",
bdevname(dev->binding->bd_dev), (long int)to, len, buf);
/* handle readonly and out of range numbers */
if(!dev->wr_buf) {
err("error: trying to write to a readonly device %s", mtd->name);
return -EROFS;
}
if(to >= mtd->size) {
return -ENOSPC;
}
if(to + len > mtd->size) {
len = (mtd->size - to);
}
err = write_pages(dev, buf, to, len, retlen);
if(err < 0)
*retlen = 0;
else
err = 0;
DEBUG(2, "blkmtd: write: end, err = %d\n", err);
return err;
}
/* sync the device - wait until the write queue is empty */
static void blkmtd_sync(struct mtd_info *mtd)
{
struct blkmtd_dev *dev = mtd->priv;
struct kiobuf *iobuf = dev->wr_buf;
DEBUG(2, "blkmtd: sync: called\n");
if(iobuf == NULL)
return;
DEBUG(3, "blkmtd: kiovec: length = %d nr_pages = %d\n",
iobuf->length, iobuf->nr_pages);
down(&dev->wrbuf_mutex);
if(iobuf->nr_pages)
commit_pages(dev);
up(&dev->wrbuf_mutex);
}
#ifdef BLKMTD_PROC_DEBUG
/* procfs stuff */
static int blkmtd_proc_read(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
int len;
struct list_head *temp1, *temp2;
MOD_INC_USE_COUNT;
/* Count the size of the page lists */
len = sprintf(page, "dev\twr_idx\tmax_idx\tnrpages\tclean\tdirty\tlocked\tlru\n");
list_for_each_safe(temp1, temp2, &blkmtd_device_list) {
struct blkmtd_dev *dev = list_entry(temp1, struct blkmtd_dev,
list);
struct list_head *temp;
struct page *pagei;
int clean = 0, dirty = 0, locked = 0, lru = 0;
/* Count the size of the page lists */
list_for_each(temp, &dev->binding->bd_inode->i_mapping->clean_pages) {
pagei = list_entry(temp, struct page, list);
clean++;
if(PageLocked(pagei))
locked++;
if(PageDirty(pagei))
dirty++;
if(PageLRU(pagei))
lru++;
}
list_for_each(temp, &dev->binding->bd_inode->i_mapping->dirty_pages) {
pagei = list_entry(temp, struct page, list);
if(PageLocked(pagei))
locked++;
if(PageDirty(pagei))
dirty++;
if(PageLRU(pagei))
lru++;
}
list_for_each(temp, &dev->binding->bd_inode->i_mapping->locked_pages) {
pagei = list_entry(temp, struct page, list);
if(PageLocked(pagei))
locked++;
if(PageDirty(pagei))
dirty++;
if(PageLRU(pagei))
lru++;
}
len += sprintf(page+len, "mtd%d:\t%ld\t%d\t%ld\t%d\t%d\t%d\t%d\n",
dev->mtd_info.index,
(dev->wr_buf && dev->wr_buf->nr_pages) ?
dev->wr_buf->blocks[dev->wr_buf->nr_pages-1] : 0,
(dev->wr_buf) ? dev->wr_buf->nr_pages : 0,
dev->binding->bd_inode->i_mapping->nrpages,
clean, dirty, locked, lru);
}
if(len <= count)
*eof = 1;
MOD_DEC_USE_COUNT;
return len;
}
#endif
static void free_device(struct blkmtd_dev *dev)
{
DEBUG(2, "blkmtd: free_device() dev = %p\n", dev);
if(dev) {
del_mtd_device(&dev->mtd_info);
info("mtd%d: [%s] removed", dev->mtd_info.index,
dev->mtd_info.name + strlen("blkmtd: "));
if(dev->mtd_info.eraseregions)
kfree(dev->mtd_info.eraseregions);
if(dev->mtd_info.name)
kfree(dev->mtd_info.name);
if(dev->rd_buf) {
dev->rd_buf->locked = 0;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,4)
if(dev->rd_buf->blocks)
kfree(dev->rd_buf->blocks);
#endif
free_kiovec(1, &dev->rd_buf);
}
if(dev->wr_buf) {
dev->wr_buf->locked = 0;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,4)
if(dev->wr_buf->blocks)
kfree(dev->rw_buf->blocks);
#endif
free_kiovec(1, &dev->wr_buf);
}
if(dev->binding) {
kdev_t kdev = to_kdev_t(dev->binding->bd_dev);
invalidate_inode_pages(dev->binding->bd_inode);
set_blocksize(kdev, 1 << 10);
blkdev_put(dev->binding, BDEV_RAW);
}
kfree(dev);
}
}
/* For a given size and initial erase size, calculate the number
* and size of each erase region. Goes round the loop twice,
* once to find out how many regions, then allocates space,
* then round the loop again to fill it in.
*/
static struct mtd_erase_region_info *calc_erase_regions(
size_t erase_size, size_t total_size, int *regions)
{
struct mtd_erase_region_info *info = NULL;
DEBUG(2, "calc_erase_regions, es = %d size = %d regions = %d\n",
erase_size, total_size, *regions);
/* Make any user specified erasesize be a power of 2
and at least PAGE_SIZE */
if(erase_size) {
int es = erase_size;
erase_size = 1;
while(es != 1) {
es >>= 1;
erase_size <<= 1;
}
if(erase_size < PAGE_SIZE)
erase_size = PAGE_SIZE;
} else {
erase_size = CONFIG_MTD_BLKDEV_ERASESIZE;
}
*regions = 0;
do {
int tot_size = total_size;
int er_size = erase_size;
int count = 0, offset = 0, regcnt = 0;
while(tot_size) {
count = tot_size / er_size;
if(count) {
tot_size = tot_size % er_size;
if(info) {
DEBUG(2, "adding to erase info off=%d er=%d cnt=%d\n",
offset, er_size, count);
(info+regcnt)->offset = offset;
(info+regcnt)->erasesize = er_size;
(info+regcnt)->numblocks = count;
(*regions)++;
}
regcnt++;
offset += (count * er_size);
}
while(er_size > tot_size)
er_size >>= 1;
}
if(info == NULL) {
info = kmalloc(regcnt * sizeof(struct mtd_erase_region_info), GFP_KERNEL);
if(!info)
break;
}
} while(!(*regions));
DEBUG(2, "calc_erase_regions done, es = %d size = %d regions = %d\n",
erase_size, total_size, *regions);
return info;
}
extern kdev_t name_to_kdev_t(char *line) __init;
static struct blkmtd_dev *add_device(char *devname, int readonly, int erase_size)
{
int maj, min;
kdev_t kdev;
int mode;
struct blkmtd_dev *dev;
#ifdef MODULE
struct file *file = NULL;
struct inode *inode;
#endif
if(!devname)
return NULL;
/* Get a handle on the device */
mode = (readonly) ? O_RDONLY : O_RDWR;
#ifdef MODULE
file = filp_open(devname, mode, 0);
if(IS_ERR(file)) {
err("error: cant open device %s", devname);
DEBUG(2, "blkmtd: filp_open returned %ld\n", PTR_ERR(file));
return NULL;
}
/* determine is this is a block device and
* if so get its major and minor numbers
*/
inode = file->f_dentry->d_inode;
if(!S_ISBLK(inode->i_mode)) {
err("%s not a block device", devname);
filp_close(file, NULL);
return NULL;
}
kdev = inode->i_rdev;
filp_close(file, NULL);
#else
kdev = name_to_kdev_t(devname);
#endif /* MODULE */
if(!kdev) {
err("bad block device: `%s'", devname);
return NULL;
}
maj = MAJOR(kdev);
min = MINOR(kdev);
DEBUG(1, "blkmtd: found a block device major = %d, minor = %d\n",
maj, min);
if(maj == MTD_BLOCK_MAJOR) {
err("attempting to use an MTD device as a block device");
return NULL;
}
DEBUG(1, "blkmtd: devname = %s\n", bdevname(kdev));
dev = kmalloc(sizeof(struct blkmtd_dev), GFP_KERNEL);
if(dev == NULL)
return NULL;
memset(dev, 0, sizeof(struct blkmtd_dev));
if(alloc_kiovec(1, &dev->rd_buf)) {
err("cant allocate read iobuf");
goto devinit_err;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,4)
dev->rd_buf->blocks = kmalloc(KIO_MAX_SECTORS * sizeof(unsigned long), GFP_KERNEL);
if(dev->rd_buf->blocks == NULL) {
crit("cant allocate rd_buf blocks");
goto devinit_err;
}
#endif
if(!readonly) {
if(alloc_kiovec(1, &dev->wr_buf)) {
err("cant allocate kiobuf - readonly enabled");
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,4)
} else {
dev->wr_buf->blocks = kmalloc(KIO_MAX_SECTORS * sizeof(unsigned long), GFP_KERNEL);
if(dev->wr_buf->blocks == NULL) {
crit("cant allocate wr_buf blocks - readonly enabled");
free_kiovec(1, &iobuf);
}
#endif
}
if(dev->wr_buf)
init_MUTEX(&dev->wrbuf_mutex);
}
/* get the block device */
dev->binding = bdget(kdev_t_to_nr(MKDEV(maj, min)));
if(blkdev_get(dev->binding, mode, 0, BDEV_RAW))
goto devinit_err;
if(set_blocksize(kdev, PAGE_SIZE)) {
err("cant set block size to PAGE_SIZE on %s", bdevname(kdev));
goto devinit_err;
}
dev->mtd_info.size = dev->binding->bd_inode->i_size & PAGE_MASK;
/* Setup the MTD structure */
/* make the name contain the block device in */
dev->mtd_info.name = kmalloc(sizeof("blkmtd: ") + strlen(devname), GFP_KERNEL);
if(dev->mtd_info.name == NULL)
goto devinit_err;
sprintf(dev->mtd_info.name, "blkmtd: %s", devname);
dev->mtd_info.eraseregions = calc_erase_regions(erase_size, dev->mtd_info.size,
&dev->mtd_info.numeraseregions);
if(dev->mtd_info.eraseregions == NULL)
goto devinit_err;
dev->mtd_info.erasesize = dev->mtd_info.eraseregions->erasesize;
DEBUG(1, "blkmtd: init: found %d erase regions\n",
dev->mtd_info.numeraseregions);
if(readonly) {
dev->mtd_info.type = MTD_ROM;
dev->mtd_info.flags = MTD_CAP_ROM;
} else {
dev->mtd_info.type = MTD_RAM;
dev->mtd_info.flags = MTD_CAP_RAM;
}
dev->mtd_info.erase = blkmtd_erase;
dev->mtd_info.read = blkmtd_read;
dev->mtd_info.write = blkmtd_write;
dev->mtd_info.sync = blkmtd_sync;
dev->mtd_info.point = 0;
dev->mtd_info.unpoint = 0;
dev->mtd_info.priv = dev;
dev->mtd_info.module = THIS_MODULE;
list_add(&dev->list, &blkmtd_device_list);
if (add_mtd_device(&dev->mtd_info)) {
/* Device didnt get added, so free the entry */
list_del(&dev->list);
free_device(dev);
return NULL;
} else {
info("mtd%d: [%s] erase_size = %dKiB %s",
dev->mtd_info.index, dev->mtd_info.name + strlen("blkmtd: "),
dev->mtd_info.erasesize >> 10,
(dev->wr_buf) ? "" : "(read-only)");
}
return dev;
devinit_err:
free_device(dev);
return NULL;
}
/* Cleanup and exit - sync the device and kill of the kernel thread */
static void __devexit cleanup_blkmtd(void)
{
struct list_head *temp1, *temp2;
#ifdef BLKMTD_PROC_DEBUG
if(blkmtd_proc) {
remove_proc_entry("blkmtd_debug", NULL);
}
#endif
/* Remove the MTD devices */
list_for_each_safe(temp1, temp2, &blkmtd_device_list) {
struct blkmtd_dev *dev = list_entry(temp1, struct blkmtd_dev,
list);
blkmtd_sync(&dev->mtd_info);
free_device(dev);
}
}
#ifndef MODULE
/* Handle kernel boot params */
static int __init param_blkmtd_device(char *str)
{
int i;
for(i = 0; i < MAX_DEVICES; i++) {
device[i] = str;
DEBUG(2, "blkmtd: device setup: %d = %s\n", i, device[i]);
strsep(&str, ",");
}
return 1;
}
static int __init param_blkmtd_erasesz(char *str)
{
int i;
for(i = 0; i < MAX_DEVICES; i++) {
char *val = strsep(&str, ",");
if(val)
erasesz[i] = simple_strtoul(val, NULL, 0);
DEBUG(2, "blkmtd: erasesz setup: %d = %d\n", i, erasesz[i]);
}
return 1;
}
static int __init param_blkmtd_ro(char *str)
{
int i;
for(i = 0; i < MAX_DEVICES; i++) {
char *val = strsep(&str, ",");
if(val)
ro[i] = simple_strtoul(val, NULL, 0);
DEBUG(2, "blkmtd: ro setup: %d = %d\n", i, ro[i]);
}
return 1;
}
static int __init param_blkmtd_sync(char *str)
{
if(str[0] == '1')
sync = 1;
return 1;
}
__setup("blkmtd_device=", param_blkmtd_device);
__setup("blkmtd_erasesz=", param_blkmtd_erasesz);
__setup("blkmtd_ro=", param_blkmtd_ro);
__setup("blkmtd_sync=", param_blkmtd_sync);
#endif
/* Startup */
static int __init init_blkmtd(void)
{
int i;
/* Check args - device[0] is the bare minimum*/
if(!device[0]) {
err("error: missing `device' name\n");
return -EINVAL;
}
for(i = 0; i < MAX_DEVICES; i++)
add_device(device[i], ro[i], erasesz[i] << 10);
if(list_empty(&blkmtd_device_list))
goto init_err;
info("version " VERSION);
#ifdef BLKMTD_PROC_DEBUG
/* create proc entry */
DEBUG(2, "Creating /proc/blkmtd_debug\n");
blkmtd_proc = create_proc_read_entry("blkmtd_debug", 0444,
NULL, blkmtd_proc_read, NULL);
if(blkmtd_proc == NULL) {
err("Cant create /proc/blkmtd_debug");
} else {
blkmtd_proc->owner = THIS_MODULE;
}
#endif
if(!list_empty(&blkmtd_device_list))
/* Everything is ok if we got here */
return 0;
init_err:
return -EINVAL;
}
module_init(init_blkmtd);
module_exit(cleanup_blkmtd);
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