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/*
* $Id: blkmtd.c,v 1.7 2001/11/10 17:06:30 spse Exp $
*
* blkmtd.c - use a block device as a fake MTD
*
* Author: Simon Evans <spse@secret.org.uk>
*
* Copyright (C) 2001 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 but make a copy of the new page(s) and then a kernel
* thread writes pages out to the device in the background. This
* ensures that writes are order even if a page is updated twice.
* Also, since pages in the page cache are never marked as dirty,
* we dont have to worry about writepage() being called on some
* random page which may not be in the write order.
*
* Erases are handled like writes, so the callback is called after
* the page cache has been updated. Sync()ing will wait until it is
* all done.
*
* It can be loaded Read-Only to prevent erases and writes to the
* medium.
*
* Todo:
* Make the write queue size dynamic so this it is not too big on
* small memory systems and too small on large memory systems.
*
* Page cache usage may still be a bit wrong. Check we are doing
* everything properly.
*
* Somehow allow writes to dirty the page cache so we dont use too
* much memory making copies of outgoing pages. Need to handle case
* where page x is written to, then page y, then page x again before
* any of them have been committed to disk.
*
* Reading should read multiple pages at once rather than using
* readpage() for each one. This is easy and will be fixed asap.
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/iobuf.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/mtd/compatmac.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
/* Default erase size in K, always make it a multiple of PAGE_SIZE */
#define CONFIG_MTD_BLKDEV_ERASESIZE 128
#define VERSION "1.7"
extern int *blk_size[];
extern int *blksize_size[];
/* Info for the block device */
typedef struct mtd_raw_dev_data_s {
struct block_device *binding;
int sector_size, sector_bits;
int partial_last_page; // 0 if device ends on page boundary, else page no of last page
int last_page_sectors; // Number of sectors in last page if partial_last_page != 0
size_t totalsize;
int readonly;
struct address_space as;
struct mtd_info mtd_info;
} mtd_raw_dev_data_t;
/* Info for each queue item in the write queue */
typedef struct mtdblkdev_write_queue_s {
mtd_raw_dev_data_t *rawdevice;
struct page **pages;
int pagenr;
int pagecnt;
int iserase;
} mtdblkdev_write_queue_t;
/* Our erase page - always remains locked. */
static struct page *erase_page;
/* Static info about the MTD, used in cleanup_module */
static mtd_raw_dev_data_t *mtd_rawdevice;
/* Write queue fixed size */
#define WRITE_QUEUE_SZ 512
/* Storage for the write queue */
static mtdblkdev_write_queue_t *write_queue;
static int write_queue_sz = WRITE_QUEUE_SZ;
static int volatile write_queue_head;
static int volatile write_queue_tail;
static int volatile write_queue_cnt;
static spinlock_t mbd_writeq_lock = SPIN_LOCK_UNLOCKED;
/* Tell the write thread to finish */
static volatile int write_task_finish;
/* ipc with the write thread */
#if LINUX_VERSION_CODE > KERNEL_VERSION(2,3,0)
static DECLARE_MUTEX_LOCKED(thread_sem);
static DECLARE_WAIT_QUEUE_HEAD(thr_wq);
static DECLARE_WAIT_QUEUE_HEAD(mtbd_sync_wq);
#else
static struct semaphore thread_sem = MUTEX_LOCKED;
DECLARE_WAIT_QUEUE_HEAD(thr_wq);
DECLARE_WAIT_QUEUE_HEAD(mtbd_sync_wq);
#endif
/* Module parameters passed by insmod/modprobe */
char *device; /* the block device to use */
int erasesz; /* optional default erase size */
int ro; /* optional read only flag */
int bs; /* optionally force the block size (avoid using) */
int count; /* optionally force the block count (avoid using) */
int wqs; /* optionally set the write queue size */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Simon Evans <spse@secret.org.uk>");
MODULE_DESCRIPTION("Emulate an MTD using a block device");
MODULE_PARM(device, "s");
MODULE_PARM_DESC(device, "block device to use");
MODULE_PARM(erasesz, "i");
MODULE_PARM_DESC(erasesz, "optional erase size to use in KB. eg 4=4K.");
MODULE_PARM(ro, "i");
MODULE_PARM_DESC(ro, "1=Read only, writes and erases cause errors");
MODULE_PARM(bs, "i");
MODULE_PARM_DESC(bs, "force the block size in bytes");
MODULE_PARM(count, "i");
MODULE_PARM_DESC(count, "force the block count");
MODULE_PARM(wqs, "i");
#endif
/* Page cache stuff */
/* writepage() - should never be called - catch it anyway */
static int blkmtd_writepage(struct page *page)
{
printk("blkmtd: writepage called!!!\n");
return -EIO;
}
/* readpage() - reads one page from the block device */
static int blkmtd_readpage(mtd_raw_dev_data_t *rawdevice, struct page *page)
{
int err;
int sectornr, sectors, i;
struct kiobuf *iobuf;
kdev_t dev;
unsigned long *blocks;
if(!rawdevice) {
printk("blkmtd: readpage: PANIC file->private_data == NULL\n");
return -EIO;
}
dev = to_kdev_t(rawdevice->binding->bd_dev);
DEBUG(2, "blkmtd: readpage called, dev = `%s' page = %p index = %ld\n",
bdevname(dev), page, page->index);
if(Page_Uptodate(page)) {
DEBUG(2, "blkmtd: readpage page %ld is already upto date\n", page->index);
UnlockPage(page);
return 0;
}
ClearPageUptodate(page);
ClearPageError(page);
/* see if page is in the outgoing write queue */
spin_lock(&mbd_writeq_lock);
if(write_queue_cnt) {
int i = write_queue_tail;
while(i != write_queue_head) {
mtdblkdev_write_queue_t *item = &write_queue[i];
if(page->index >= item->pagenr && page->index < item->pagenr+item->pagecnt) {
/* yes it is */
int index = page->index - item->pagenr;
DEBUG(2, "blkmtd: readpage: found page %ld in outgoing write queue\n",
page->index);
if(item->iserase) {
memset(page_address(page), 0xff, PAGE_SIZE);
} else {
memcpy(page_address(page), page_address(item->pages[index]), PAGE_SIZE);
}
SetPageUptodate(page);
flush_dcache_page(page);
UnlockPage(page);
spin_unlock(&mbd_writeq_lock);
return 0;
}
i++;
i %= write_queue_sz;
}
}
spin_unlock(&mbd_writeq_lock);
DEBUG(3, "blkmtd: readpage: getting kiovec\n");
err = alloc_kiovec(1, &iobuf);
if (err) {
printk("blkmtd: cant allocate kiobuf\n");
SetPageError(page);
return err;
}
/* Pre 2.4.4 doesnt have space for the block list in the kiobuf */
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,4)
blocks = kmalloc(KIO_MAX_SECTORS * sizeof(unsigned long));
if(blocks == NULL) {
printk("blkmtd: cant allocate iobuf blocks\n");
free_kiovec(1, &iobuf);
SetPageError(page);
return -ENOMEM;
}
#else
blocks = iobuf->blocks;
#endif
iobuf->offset = 0;
iobuf->nr_pages = 1;
iobuf->length = PAGE_SIZE;
iobuf->locked = 1;
iobuf->maplist[0] = page;
sectornr = page->index << (PAGE_SHIFT - rawdevice->sector_bits);
sectors = 1 << (PAGE_SHIFT - rawdevice->sector_bits);
if(rawdevice->partial_last_page && page->index == rawdevice->partial_last_page) {
DEBUG(3, "blkmtd: handling partial last page\n");
sectors = rawdevice->last_page_sectors;
}
DEBUG(3, "blkmtd: readpage: sectornr = %d sectors = %d\n", sectornr, sectors);
for(i = 0; i < sectors; i++) {
blocks[i] = sectornr++;
}
/* If only a partial page read in, clear the rest of the page */
if(rawdevice->partial_last_page && page->index == rawdevice->partial_last_page) {
int offset = rawdevice->last_page_sectors << rawdevice->sector_bits;
int count = PAGE_SIZE-offset;
DEBUG(3, "blkmtd: clear last partial page: offset = %d count = %d\n", offset, count);
memset(page_address(page)+offset, 0, count);
sectors = rawdevice->last_page_sectors;
}
DEBUG(3, "bklmtd: readpage: starting brw_kiovec\n");
err = brw_kiovec(READ, 1, &iobuf, dev, blocks, rawdevice->sector_size);
DEBUG(3, "blkmtd: readpage: finished, err = %d\n", err);
iobuf->locked = 0;
free_kiovec(1, &iobuf);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,4)
kfree(blocks);
#endif
if(err != PAGE_SIZE) {
printk("blkmtd: readpage: error reading page %ld\n", page->index);
memset(page_address(page), 0, PAGE_SIZE);
SetPageError(page);
err = -EIO;
} else {
DEBUG(3, "blkmtd: readpage: setting page upto date\n");
SetPageUptodate(page);
err = 0;
}
flush_dcache_page(page);
UnlockPage(page);
DEBUG(2, "blkmtd: readpage: finished, err = %d\n", err);
return 0;
}
static struct address_space_operations blkmtd_aops = {
writepage: blkmtd_writepage,
readpage: NULL,
};
/* This is the kernel thread that empties the write queue to disk */
static int write_queue_task(void *data)
{
int err;
struct task_struct *tsk = current;
struct kiobuf *iobuf;
unsigned long *blocks;
DECLARE_WAITQUEUE(wait, tsk);
DEBUG(1, "blkmtd: writetask: starting (pid = %d)\n", tsk->pid);
daemonize();
strcpy(tsk->comm, "blkmtdd");
tsk->tty = NULL;
spin_lock_irq(&tsk->sigmask_lock);
sigfillset(&tsk->blocked);
recalc_sigpending(tsk);
spin_unlock_irq(&tsk->sigmask_lock);
exit_sighand(tsk);
if(alloc_kiovec(1, &iobuf)) {
printk("blkmtd: write_queue_task cant allocate kiobuf\n");
return 0;
}
/* Pre 2.4.4 doesnt have space for the block list in the kiobuf */
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,4)
blocks = kmalloc(KIO_MAX_SECTORS * sizeof(unsigned long));
if(blocks == NULL) {
printk("blkmtd: write_queue_task cant allocate iobuf blocks\n");
free_kiovec(1, &iobuf);
return 0;
}
#else
blocks = iobuf->blocks;
#endif
DEBUG(2, "blkmtd: writetask: entering main loop\n");
add_wait_queue(&thr_wq, &wait);
while(1) {
spin_lock(&mbd_writeq_lock);
if(!write_queue_cnt) {
/* If nothing in the queue, wake up anyone wanting to know when there
is space in the queue then sleep for 2*HZ */
spin_unlock(&mbd_writeq_lock);
DEBUG(4, "blkmtd: writetask: queue empty\n");
if(waitqueue_active(&mtbd_sync_wq))
wake_up(&mtbd_sync_wq);
interruptible_sleep_on_timeout(&thr_wq, 2*HZ);
DEBUG(4, "blkmtd: writetask: woken up\n");
if(write_task_finish)
break;
} else {
/* we have stuff to write */
mtdblkdev_write_queue_t *item = &write_queue[write_queue_tail];
struct page **pages = item->pages;
int i;
int sectornr = item->pagenr << (PAGE_SHIFT - item->rawdevice->sector_bits);
int sectorcnt = item->pagecnt << (PAGE_SHIFT - item->rawdevice->sector_bits);
int max_sectors = KIO_MAX_SECTORS >> (item->rawdevice->sector_bits - 9);
kdev_t dev = to_kdev_t(item->rawdevice->binding->bd_dev);
/* If we are writing to the last page on the device and it doesnt end
* on a page boundary, subtract the number of sectors that dont exist.
*/
if(item->rawdevice->partial_last_page &&
(item->pagenr + item->pagecnt -1) == item->rawdevice->partial_last_page) {
sectorcnt -= (1 << (PAGE_SHIFT - item->rawdevice->sector_bits));
sectorcnt += item->rawdevice->last_page_sectors;
}
DEBUG(3, "blkmtd: writetask: got %d queue items\n", write_queue_cnt);
set_current_state(TASK_RUNNING);
spin_unlock(&mbd_writeq_lock);
DEBUG(2, "blkmtd: writetask: writing pagenr = %d pagecnt = %d sectornr = %d sectorcnt = %d\n",
item->pagenr, item->pagecnt, sectornr, sectorcnt);
iobuf->offset = 0;
iobuf->locked = 1;
/* Loop through all the pages to be written in the queue item, remembering
we can only write KIO_MAX_SECTORS at a time */
while(sectorcnt) {
int cursectors = (sectorcnt < max_sectors) ? sectorcnt : max_sectors;
int cpagecnt = (cursectors << item->rawdevice->sector_bits) + PAGE_SIZE-1;
cpagecnt >>= PAGE_SHIFT;
for(i = 0; i < cpagecnt; i++) {
if(item->iserase) {
iobuf->maplist[i] = erase_page;
} else {
iobuf->maplist[i] = *(pages++);
}
}
for(i = 0; i < cursectors; i++) {
blocks[i] = sectornr++;
}
iobuf->nr_pages = cpagecnt;
iobuf->length = cursectors << item->rawdevice->sector_bits;
DEBUG(3, "blkmtd: write_task: about to kiovec\n");
err = brw_kiovec(WRITE, 1, &iobuf, dev, blocks, item->rawdevice->sector_size);
DEBUG(3, "bklmtd: write_task: done, err = %d\n", err);
if(err != (cursectors << item->rawdevice->sector_bits)) {
/* if an error occured - set this to exit the loop */
sectorcnt = 0;
} else {
sectorcnt -= cursectors;
}
}
/* free up the pages used in the write and list of pages used in the write
queue item */
iobuf->locked = 0;
spin_lock(&mbd_writeq_lock);
write_queue_cnt--;
write_queue_tail++;
write_queue_tail %= write_queue_sz;
if(!item->iserase) {
for(i = 0 ; i < item->pagecnt; i++) {
UnlockPage(item->pages[i]);
__free_pages(item->pages[i], 0);
}
kfree(item->pages);
}
item->pages = NULL;
spin_unlock(&mbd_writeq_lock);
/* Tell others there is some space in the write queue */
if(waitqueue_active(&mtbd_sync_wq))
wake_up(&mtbd_sync_wq);
}
}
remove_wait_queue(&thr_wq, &wait);
DEBUG(1, "blkmtd: writetask: exiting\n");
free_kiovec(1, &iobuf);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,4)
kfree(blocks);
#endif
/* Tell people we have exitd */
up(&thread_sem);
return 0;
}
/* Add a range of pages into the outgoing write queue, making copies of them */
static int queue_page_write(mtd_raw_dev_data_t *rawdevice, struct page **pages,
int pagenr, int pagecnt, int iserase)
{
struct page *outpage;
struct page **new_pages = NULL;
mtdblkdev_write_queue_t *item;
int i;
DECLARE_WAITQUEUE(wait, current);
DEBUG(2, "blkmtd: queue_page_write: adding pagenr = %d pagecnt = %d\n", pagenr, pagecnt);
if(!pagecnt)
return 0;
if(pages == NULL && !iserase)
return -EINVAL;
/* create a array for the list of pages */
if(!iserase) {
new_pages = kmalloc(pagecnt * sizeof(struct page *), GFP_KERNEL);
if(new_pages == NULL)
return -ENOMEM;
/* make copies of the pages in the page cache */
for(i = 0; i < pagecnt; i++) {
outpage = alloc_pages(GFP_KERNEL, 0);
if(!outpage) {
while(i--) {
UnlockPage(new_pages[i]);
__free_pages(new_pages[i], 0);
}
kfree(new_pages);
return -ENOMEM;
}
lock_page(outpage);
memcpy(page_address(outpage), page_address(pages[i]), PAGE_SIZE);
new_pages[i] = outpage;
}
}
/* wait until there is some space in the write queue */
test_lock:
spin_lock(&mbd_writeq_lock);
if(write_queue_cnt == write_queue_sz) {
spin_unlock(&mbd_writeq_lock);
DEBUG(3, "blkmtd: queue_page: Queue full\n");
current->state = TASK_UNINTERRUPTIBLE;
add_wait_queue(&mtbd_sync_wq, &wait);
wake_up_interruptible(&thr_wq);
schedule();
current->state = TASK_RUNNING;
remove_wait_queue(&mtbd_sync_wq, &wait);
DEBUG(3, "blkmtd: queue_page_write: Queue has %d items in it\n", write_queue_cnt);
goto test_lock;
}
DEBUG(3, "blkmtd: queue_page_write: qhead: %d qtail: %d qcnt: %d\n",
write_queue_head, write_queue_tail, write_queue_cnt);
/* fix up the queue item */
item = &write_queue[write_queue_head];
item->pages = new_pages;
item->pagenr = pagenr;
item->pagecnt = pagecnt;
item->rawdevice = rawdevice;
item->iserase = iserase;
write_queue_head++;
write_queue_head %= write_queue_sz;
write_queue_cnt++;
DEBUG(3, "blkmtd: queue_page_write: qhead: %d qtail: %d qcnt: %d\n",
write_queue_head, write_queue_tail, write_queue_cnt);
spin_unlock(&mbd_writeq_lock);
DEBUG(2, "blkmtd: queue_page_write: finished\n");
return 0;
}
/* erase a specified part of the device */
static int blkmtd_erase(struct mtd_info *mtd, struct erase_info *instr)
{
mtd_raw_dev_data_t *rawdevice = mtd->priv;
struct mtd_erase_region_info *einfo = mtd->eraseregions;
int numregions = mtd->numeraseregions;
size_t from;
u_long len;
int err = 0;
/* check readonly */
if(rawdevice->readonly) {
printk("blkmtd: error: trying to erase readonly device %s\n", device);
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(rawdevice->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 */
printk("blkmtd: erase: invalid erase request 0x%lX @ 0x%08X\n", len, from);
instr->state = MTD_ERASE_FAILED;
err = -EIO;
}
if(instr->state != MTD_ERASE_FAILED) {
/* start the erase */
int pagenr, pagecnt;
struct page *page, **pages;
int i = 0;
/* Handle the last page of the device not being whole */
if(len < PAGE_SIZE)
len = PAGE_SIZE;
pagenr = from >> PAGE_SHIFT;
pagecnt = len >> PAGE_SHIFT;
DEBUG(3, "blkmtd: erase: pagenr = %d pagecnt = %d\n", pagenr, pagecnt);
pages = kmalloc(pagecnt * sizeof(struct page *), GFP_KERNEL);
if(pages == NULL) {
err = -ENOMEM;
instr->state = MTD_ERASE_FAILED;
goto erase_out;
}
while(pagecnt) {
/* get the page via the page cache */
DEBUG(3, "blkmtd: erase: doing grab_cache_page() for page %d\n", pagenr);
page = grab_cache_page(&rawdevice->as, pagenr);
if(!page) {
DEBUG(3, "blkmtd: erase: grab_cache_page() failed for page %d\n", pagenr);
kfree(pages);
err = -EIO;
instr->state = MTD_ERASE_FAILED;
goto erase_out;
}
memset(page_address(page), 0xff, PAGE_SIZE);
pages[i] = page;
pagecnt--;
pagenr++;
i++;
}
DEBUG(3, "blkmtd: erase: queuing page write\n");
err = queue_page_write(rawdevice, NULL, from >> PAGE_SHIFT, len >> PAGE_SHIFT, 1);
pagecnt = len >> PAGE_SHIFT;
if(!err) {
while(pagecnt--) {
SetPageUptodate(pages[pagecnt]);
UnlockPage(pages[pagecnt]);
page_cache_release(pages[pagecnt]);
flush_dcache_page(pages[pagecnt]);
}
kfree(pages);
instr->state = MTD_ERASE_DONE;
} else {
while(pagecnt--) {
SetPageError(pages[pagecnt]);
page_cache_release(pages[pagecnt]);
}
kfree(pages);
instr->state = MTD_ERASE_FAILED;
}
}
erase_out:
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)
{
mtd_raw_dev_data_t *rawdevice = mtd->priv;
int err = 0;
int offset;
int pagenr, pages;
*retlen = 0;
DEBUG(2, "blkmtd: read: dev = `%s' from = %ld len = %d buf = %p\n",
bdevname(rawdevice->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);
/* just loop through each page, getting it via readpage() - slow but easy */
while(pages) {
struct page *page;
int cpylen;
DEBUG(3, "blkmtd: read: looking for page: %d\n", pagenr);
page = read_cache_page(&rawdevice->as, pagenr, (filler_t *)blkmtd_readpage, rawdevice);
if(IS_ERR(page)) {
return PTR_ERR(page);
}
wait_on_page(page);
if(!Page_Uptodate(page)) {
/* error reading page */
printk("blkmtd: read: page not uptodate\n");
page_cache_release(page);
return -EIO;
}
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--;
page_cache_release(page);
}
DEBUG(2, "blkmtd: end read: retlen = %d, err = %d\n", *retlen, err);
return err;
}
/* write a range of the data via the page cache.
*
* Basic operation. break the write into three parts.
*
* 1. From a page unaligned start up until the next page boundary
* 2. Page sized, page aligned blocks
* 3. From end of last aligned block to end of range
*
* 1,3 are read via the page cache and readpage() since these are partial
* pages, 2 we just grab pages from the page cache, not caring if they are
* already in memory or not since they will be completly overwritten.
*
*/
static int blkmtd_write(struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, const u_char *buf)
{
mtd_raw_dev_data_t *rawdevice = mtd->priv;
int err = 0;
int offset;
int pagenr;
size_t len1 = 0, len2 = 0, len3 = 0;
struct page **pages;
int pagecnt = 0;
*retlen = 0;
DEBUG(2, "blkmtd: write: dev = `%s' to = %ld len = %d buf = %p\n",
bdevname(rawdevice->binding->bd_dev), (long int)to, len, buf);
/* handle readonly and out of range numbers */
if(rawdevice->readonly) {
printk("blkmtd: error: trying to write to a readonly device %s\n", device);
return -EROFS;
}
if(to >= rawdevice->totalsize) {
return -ENOSPC;
}
if(to + len > rawdevice->totalsize) {
len = (rawdevice->totalsize - to);
}
pagenr = to >> PAGE_SHIFT;
offset = to - (pagenr << PAGE_SHIFT);
/* see if we have to do a partial write at the start */
if(offset) {
if((offset + len) > PAGE_SIZE) {
len1 = PAGE_SIZE - offset;
len -= len1;
} else {
len1 = len;
len = 0;
}
}
/* calculate the length of the other two regions */
len3 = len & ~PAGE_MASK;
len -= len3;
len2 = len;
if(len1)
pagecnt++;
if(len2)
pagecnt += len2 >> PAGE_SHIFT;
if(len3)
pagecnt++;
DEBUG(3, "blkmtd: write: len1 = %d len2 = %d len3 = %d pagecnt = %d\n", len1, len2, len3, pagecnt);
/* get space for list of pages */
pages = kmalloc(pagecnt * sizeof(struct page *), GFP_KERNEL);
if(pages == NULL) {
return -ENOMEM;
}
pagecnt = 0;
if(len1) {
/* do partial start region */
struct page *page;
DEBUG(3, "blkmtd: write: doing partial start, page = %d len = %d offset = %d\n", pagenr, len1, offset);
page = read_cache_page(&rawdevice->as, pagenr, (filler_t *)blkmtd_readpage, rawdevice);
if(IS_ERR(page)) {
kfree(pages);
return PTR_ERR(page);
}
memcpy(page_address(page)+offset, buf, len1);
pages[pagecnt++] = page;
buf += len1;
*retlen = len1;
err = 0;
pagenr++;
}
/* Now do the main loop to a page aligned, n page sized output */
if(len2) {
int pagesc = len2 >> 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(&rawdevice->as, pagenr);
DEBUG(3, "blkmtd: write: got page %d from page cache\n", pagenr);
if(!page) {
printk("blkmtd: write: cant grab cache page %d\n", pagenr);
err = -EIO;
goto write_err;
}
memcpy(page_address(page), buf, PAGE_SIZE);
pages[pagecnt++] = page;
UnlockPage(page);
SetPageUptodate(page);
pagenr++;
pagesc--;
buf += PAGE_SIZE;
*retlen += PAGE_SIZE;
}
}
if(len3) {
/* do the third region */
struct page *page;
DEBUG(3, "blkmtd: write: doing partial end, page = %d len = %d\n", pagenr, len3);
page = read_cache_page(&rawdevice->as, pagenr, (filler_t *)blkmtd_readpage, rawdevice);
if(IS_ERR(page)) {
err = PTR_ERR(page);
goto write_err;
}
memcpy(page_address(page), buf, len3);
DEBUG(3, "blkmtd: write: writing out partial end\n");
pages[pagecnt++] = page;
*retlen += len3;
err = 0;
}
DEBUG(2, "blkmtd: write: end, retlen = %d, err = %d\n", *retlen, err);
/* submit it to the write task */
err = queue_page_write(rawdevice, pages, to >> PAGE_SHIFT, pagecnt, 0);
if(!err) {
while(pagecnt--) {
SetPageUptodate(pages[pagecnt]);
flush_dcache_page(pages[pagecnt]);
page_cache_release(pages[pagecnt]);
}
kfree(pages);
return 0;
}
write_err:
while(--pagecnt) {
SetPageError(pages[pagecnt]);
page_cache_release(pages[pagecnt]);
}
kfree(pages);
return err;
}
/* sync the device - wait until the write queue is empty */
static void blkmtd_sync(struct mtd_info *mtd)
{
DECLARE_WAITQUEUE(wait, current);
mtd_raw_dev_data_t *rawdevice = mtd->priv;
if(rawdevice->readonly)
return;
DEBUG(2, "blkmtd: sync: called\n");
stuff_inq:
spin_lock(&mbd_writeq_lock);
if(write_queue_cnt) {
spin_unlock(&mbd_writeq_lock);
current->state = TASK_UNINTERRUPTIBLE;
add_wait_queue(&mtbd_sync_wq, &wait);
DEBUG(3, "blkmtd: sync: waking up task\n");
wake_up_interruptible(&thr_wq);
schedule();
current->state = TASK_RUNNING;
remove_wait_queue(&mtbd_sync_wq, &wait);
DEBUG(3, "blkmtd: sync: waking up after write task\n");
goto stuff_inq;
}
spin_unlock(&mbd_writeq_lock);
DEBUG(2, "blkmtd: sync: finished\n");
}
#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 clean = 0, dirty = 0, locked = 0;
struct list_head *temp;
int i, len, pages = 0, cnt;
MOD_INC_USE_COUNT;
spin_lock(&mbd_writeq_lock);
cnt = write_queue_cnt;
i = write_queue_tail;
while(cnt) {
if(!write_queue[i].iserase)
pages += write_queue[i].pagecnt;
i++;
i %= write_queue_sz;
cnt--;
}
/* Count the size of the page lists */
list_for_each(temp, &mtd_rawdevice->as.clean_pages) {
clean++;
}
list_for_each(temp, &mtd_rawdevice->as.dirty_pages) {
dirty++;
}
list_for_each(temp, &mtd_rawdevice->as.locked_pages) {
locked++;
}
len = sprintf(page, "Write queue head: %d\nWrite queue tail: %d\n"
"Write queue count: %d\nPages in queue: %d (%dK)\n"
"Clean Pages: %d\nDirty Pages: %d\nLocked Pages: %d\n"
"nrpages: %ld\n",
write_queue_head, write_queue_tail, write_queue_cnt,
pages, pages << (PAGE_SHIFT-10), clean, dirty, locked,
mtd_rawdevice->as.nrpages);
if(len <= count)
*eof = 1;
spin_unlock(&mbd_writeq_lock);
MOD_DEC_USE_COUNT;
return len;
}
#endif
/* Cleanup and exit - sync the device and kill of the kernel thread */
static void __exit cleanup_blkmtd(void)
{
#ifdef BLKMTD_PROC_DEBUG
if(blkmtd_proc) {
remove_proc_entry("blkmtd_debug", NULL);
}
#endif
if (mtd_rawdevice) {
/* sync the device */
if (!mtd_rawdevice->readonly) {
blkmtd_sync(&mtd_rawdevice->mtd_info);
write_task_finish = 1;
wake_up_interruptible(&thr_wq);
down(&thread_sem);
}
del_mtd_device(&mtd_rawdevice->mtd_info);
if(mtd_rawdevice->binding != NULL)
blkdev_put(mtd_rawdevice->binding, BDEV_RAW);
if(mtd_rawdevice->mtd_info.eraseregions)
kfree(mtd_rawdevice->mtd_info.eraseregions);
if(mtd_rawdevice->mtd_info.name)
kfree(mtd_rawdevice->mtd_info.name);
kfree(mtd_rawdevice);
}
if(write_queue)
kfree(write_queue);
if(erase_page) {
UnlockPage(erase_page);
__free_pages(erase_page, 0);
}
printk("blkmtd: unloaded for %s\n", device);
}
extern struct module __this_module;
#ifndef MODULE
/* Handle kernel boot params */
static int __init param_blkmtd_device(char *str)
{
device = str;
return 1;
}
static int __init param_blkmtd_erasesz(char *str)
{
erasesz = simple_strtol(str, NULL, 0);
return 1;
}
static int __init param_blkmtd_ro(char *str)
{
ro = simple_strtol(str, NULL, 0);
return 1;
}
static int __init param_blkmtd_bs(char *str)
{
bs = simple_strtol(str, NULL, 0);
return 1;
}
static int __init param_blkmtd_count(char *str)
{
count = simple_strtol(str, NULL, 0);
return 1;
}
__setup("blkmtd_device=", param_blkmtd_device);
__setup("blkmtd_erasesz=", param_blkmtd_erasesz);
__setup("blkmtd_ro=", param_blkmtd_ro);
__setup("blkmtd_bs=", param_blkmtd_bs);
__setup("blkmtd_count=", param_blkmtd_count);
#endif
/* for a given size and initial erase size, calculate the number and size of each
erase region */
static int __init calc_erase_regions(struct mtd_erase_region_info *info, size_t erase_size, size_t total_size)
{
int count = 0;
int offset = 0;
int regions = 0;
while(total_size) {
count = total_size / erase_size;
if(count) {
total_size = total_size % erase_size;
if(info) {
info->offset = offset;
info->erasesize = erase_size;
info->numblocks = count;
info++;
}
offset += (count * erase_size);
regions++;
}
while(erase_size > total_size)
erase_size >>= 1;
}
return regions;
}
extern kdev_t name_to_kdev_t(char *line) __init;
/* Startup */
static int __init init_blkmtd(void)
{
#ifdef MODULE
struct file *file = NULL;
struct inode *inode;
#endif
int maj, min;
int i, blocksize, blocksize_bits;
loff_t size = 0;
int readonly = 0;
int erase_size = CONFIG_MTD_BLKDEV_ERASESIZE;
kdev_t rdev;
int err;
int mode;
int regions;
/* Check args */
if(device == 0) {
printk("blkmtd: error, missing `device' name\n");
return -EINVAL;
}
if(ro)
readonly = 1;
if(erasesz)
erase_size = erasesz;
if(wqs) {
if(wqs < 16)
wqs = 16;
if(wqs > 4*WRITE_QUEUE_SZ)
wqs = 4*WRITE_QUEUE_SZ;
write_queue_sz = wqs;
}
DEBUG(1, "blkmtd: device = `%s' erase size = %dK readonly = %s queue size = %d\n",
device, erase_size, readonly ? "yes" : "no", write_queue_sz);
/* Get a handle on the device */
mode = (readonly) ? O_RDONLY : O_RDWR;
#ifdef MODULE
file = filp_open(device, mode, 0);
if(IS_ERR(file)) {
printk("blkmtd: error, cant open device %s\n", device);
DEBUG(2, "blkmtd: filp_open returned %ld\n", PTR_ERR(file));
return 1;
}
/* 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)) {
printk("blkmtd: %s not a block device\n", device);
filp_close(file, NULL);
return 1;
}
rdev = inode->i_rdev;
filp_close(file, NULL);
#else
rdev = name_to_kdev_t(device);
#endif
maj = MAJOR(rdev);
min = MINOR(rdev);
DEBUG(1, "blkmtd: found a block device major = %d, minor = %d\n", maj, min);
if(!rdev) {
printk("blkmtd: bad block device: `%s'\n", device);
return 1;
}
if(maj == MTD_BLOCK_MAJOR) {
printk("blkmtd: attempting to use an MTD device as a block device\n");
return 1;
}
DEBUG(1, "blkmtd: devname = %s\n", bdevname(rdev));
blocksize = BLOCK_SIZE;
if(bs) {
blocksize = bs;
} else {
if (blksize_size[maj] && blksize_size[maj][min]) {
DEBUG(2, "blkmtd: blksize_size = %d\n", blksize_size[maj][min]);
blocksize = blksize_size[maj][min];
}
}
i = blocksize;
blocksize_bits = 0;
while(i != 1) {
blocksize_bits++;
i >>= 1;
}
if(count) {
size = count;
} else {
if (blk_size[maj]) {
size = ((loff_t) blk_size[maj][min] << BLOCK_SIZE_BITS) >> blocksize_bits;
}
}
size *= blocksize;
DEBUG(1, "blkmtd: size = %ld\n", (long int)size);
if(size == 0) {
printk("blkmtd: cant determine size\n");
return 1;
}
mtd_rawdevice = (mtd_raw_dev_data_t *)kmalloc(sizeof(mtd_raw_dev_data_t), GFP_KERNEL);
if(mtd_rawdevice == NULL) {
err = -ENOMEM;
goto init_err;
}
memset(mtd_rawdevice, 0, sizeof(mtd_raw_dev_data_t));
/* get the block device */
mtd_rawdevice->binding = bdget(kdev_t_to_nr(MKDEV(maj, min)));
err = blkdev_get(mtd_rawdevice->binding, mode, 0, BDEV_RAW);
if (err) {
goto init_err;
}
mtd_rawdevice->totalsize = size;
mtd_rawdevice->sector_size = blocksize;
mtd_rawdevice->sector_bits = blocksize_bits;
mtd_rawdevice->readonly = readonly;
/* See if device ends on page boundary */
if(size % PAGE_SIZE) {
mtd_rawdevice->partial_last_page = size >> PAGE_SHIFT;
mtd_rawdevice->last_page_sectors = (size & (PAGE_SIZE-1)) >> blocksize_bits;
}
DEBUG(2, "sector_size = %d, sector_bits = %d, partial_last_page = %d last_page_sectors = %d\n",
mtd_rawdevice->sector_size, mtd_rawdevice->sector_bits,
mtd_rawdevice->partial_last_page, mtd_rawdevice->last_page_sectors);
/* Setup the MTD structure */
/* make the name contain the block device in */
mtd_rawdevice->mtd_info.name = kmalloc(9 + strlen(device), GFP_KERNEL);
if(mtd_rawdevice->mtd_info.name == NULL)
goto init_err;
sprintf(mtd_rawdevice->mtd_info.name, "blkmtd: %s", device);
if(readonly) {
mtd_rawdevice->mtd_info.type = MTD_ROM;
mtd_rawdevice->mtd_info.flags = MTD_CAP_ROM;
mtd_rawdevice->mtd_info.erasesize = erase_size << 10;
} else {
mtd_rawdevice->mtd_info.type = MTD_RAM;
mtd_rawdevice->mtd_info.flags = MTD_CAP_RAM;
mtd_rawdevice->mtd_info.erasesize = erase_size << 10;
}
mtd_rawdevice->mtd_info.size = size;
mtd_rawdevice->mtd_info.erase = blkmtd_erase;
mtd_rawdevice->mtd_info.read = blkmtd_read;
mtd_rawdevice->mtd_info.write = blkmtd_write;
mtd_rawdevice->mtd_info.sync = blkmtd_sync;
mtd_rawdevice->mtd_info.point = 0;
mtd_rawdevice->mtd_info.unpoint = 0;
mtd_rawdevice->mtd_info.priv = mtd_rawdevice;
regions = calc_erase_regions(NULL, erase_size << 10, size);
DEBUG(1, "blkmtd: init: found %d erase regions\n", regions);
mtd_rawdevice->mtd_info.eraseregions = kmalloc(regions * sizeof(struct mtd_erase_region_info), GFP_KERNEL);
if(mtd_rawdevice->mtd_info.eraseregions == NULL) {
err = -ENOMEM;
goto init_err;
}
mtd_rawdevice->mtd_info.numeraseregions = regions;
calc_erase_regions(mtd_rawdevice->mtd_info.eraseregions, erase_size << 10, size);
/* setup the page cache info */
mtd_rawdevice->as.nrpages = 0;
INIT_LIST_HEAD(&mtd_rawdevice->as.clean_pages);
INIT_LIST_HEAD(&mtd_rawdevice->as.dirty_pages);
INIT_LIST_HEAD(&mtd_rawdevice->as.locked_pages);
mtd_rawdevice->as.host = NULL;
spin_lock_init(&(mtd_rawdevice->as.i_shared_lock));
mtd_rawdevice->as.a_ops = &blkmtd_aops;
mtd_rawdevice->as.i_mmap = NULL;
mtd_rawdevice->as.i_mmap_shared = NULL;
mtd_rawdevice->as.gfp_mask = GFP_KERNEL;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
mtd_rawdevice->mtd_info.module = THIS_MODULE;
#endif
if (add_mtd_device(&mtd_rawdevice->mtd_info)) {
err = -EIO;
goto init_err;
}
if(!mtd_rawdevice->readonly) {
/* Allocate the write queue */
write_queue = kmalloc(write_queue_sz * sizeof(mtdblkdev_write_queue_t), GFP_KERNEL);
if(!write_queue) {
err = -ENOMEM;
goto init_err;
}
/* Set up the erase page */
erase_page = alloc_pages(GFP_KERNEL, 0);
if(erase_page == NULL) {
err = -ENOMEM;
goto init_err;
}
memset(page_address(erase_page), 0xff, PAGE_SIZE);
lock_page(erase_page);
init_waitqueue_head(&thr_wq);
init_waitqueue_head(&mtbd_sync_wq);
DEBUG(3, "blkmtd: init: kernel task @ %p\n", write_queue_task);
DEBUG(2, "blkmtd: init: starting kernel task\n");
kernel_thread(write_queue_task, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGHAND);
DEBUG(2, "blkmtd: init: started\n");
printk("blkmtd loaded: version = %s using %s erase_size = %dK %s\n",
VERSION, device, erase_size, (readonly) ? "(read-only)" : "");
}
#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) {
printk("Cant create /proc/blkmtd_debug\n");
} else {
blkmtd_proc->owner = THIS_MODULE;
}
#endif
/* Everything is ok if we got here */
return 0;
init_err:
if(mtd_rawdevice) {
if(mtd_rawdevice->mtd_info.eraseregions)
kfree(mtd_rawdevice->mtd_info.eraseregions);
if(mtd_rawdevice->mtd_info.name)
kfree(mtd_rawdevice->mtd_info.name);
if(mtd_rawdevice->binding)
blkdev_put(mtd_rawdevice->binding, BDEV_RAW);
kfree(mtd_rawdevice);
}
if(write_queue) {
kfree(write_queue);
write_queue = NULL;
}
if(erase_page)
__free_pages(erase_page, 0);
return err;
}
module_init(init_blkmtd);
module_exit(cleanup_blkmtd);
|