blkmtd.c
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上传日期:2013-04-10
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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 == NULLn");
- return -EIO;
- }
- dev = to_kdev_t(rawdevice->binding->bd_dev);
- DEBUG(2, "blkmtd: readpage called, dev = `%s' page = %p index = %ldn",
- bdevname(dev), page, page->index);
- if(Page_Uptodate(page)) {
- DEBUG(2, "blkmtd: readpage page %ld is already upto daten", 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 queuen",
- 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 kiovecn");
- err = alloc_kiovec(1, &iobuf);
- if (err) {
- printk("blkmtd: cant allocate kiobufn");
- SetPageError(page);
- return err;
- }
- /* Pre 2.4.4 doesn't 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 blocksn");
- 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 pagen");
- sectors = rawdevice->last_page_sectors;
- }
- DEBUG(3, "blkmtd: readpage: sectornr = %d sectors = %dn", 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 = %dn", offset, count);
- memset(page_address(page)+offset, 0, count);
- sectors = rawdevice->last_page_sectors;
- }
- DEBUG(3, "bklmtd: readpage: starting brw_kiovecn");
- err = brw_kiovec(READ, 1, &iobuf, dev, blocks, rawdevice->sector_size);
- DEBUG(3, "blkmtd: readpage: finished, err = %dn", 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 %ldn", page->index);
- memset(page_address(page), 0, PAGE_SIZE);
- SetPageError(page);
- err = -EIO;
- } else {
- DEBUG(3, "blkmtd: readpage: setting page upto daten");
- SetPageUptodate(page);
- err = 0;
- }
- flush_dcache_page(page);
- UnlockPage(page);
- DEBUG(2, "blkmtd: readpage: finished, err = %dn", 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 kiobufn");
- return 0;
- }
- /* Pre 2.4.4 doesn't 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 blocksn");
- free_kiovec(1, &iobuf);
- return 0;
- }
- #else
- blocks = iobuf->blocks;
- #endif
- DEBUG(2, "blkmtd: writetask: entering main loopn");
- 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 emptyn");
- if(waitqueue_active(&mtbd_sync_wq))
- wake_up(&mtbd_sync_wq);
- interruptible_sleep_on_timeout(&thr_wq, 2*HZ);
- DEBUG(4, "blkmtd: writetask: woken upn");
- 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 doesn't 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 itemsn", 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 = %dn",
- 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 kiovecn");
- err = brw_kiovec(WRITE, 1, &iobuf, dev, blocks, item->rawdevice->sector_size);
- DEBUG(3, "bklmtd: write_task: done, err = %dn", 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: exitingn");
- 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 = %dn", 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 fulln");
- 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 itn", write_queue_cnt);
- goto test_lock;
- }
- DEBUG(3, "blkmtd: queue_page_write: qhead: %d qtail: %d qcnt: %dn",
- 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: %dn",
- write_queue_head, write_queue_tail, write_queue_cnt);
- spin_unlock(&mbd_writeq_lock);
- DEBUG(2, "blkmtd: queue_page_write: finishedn");
- 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 %sn", 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%lxn",
- bdevname(rawdevice->binding->bd_dev), from, len);
- while(numregions) {
- DEBUG(3, "blkmtd: checking erase region = 0x%08X size = 0x%X num = 0x%xn",
- 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%08Xn", 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 = %dn", 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 %dn", pagenr);
- page = grab_cache_page(&rawdevice->as, pagenr);
- if(!page) {
- DEBUG(3, "blkmtd: erase: grab_cache_page() failed for page %dn", 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 writen");
- 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 callbackn");
- 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 = %pn",
- 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 = %dn", 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: %dn", 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 uptodaten");
- 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 = %dn", *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 = %pn",
- 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 %sn", 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 = %dn", 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 = %dn", 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 = %dn", pagenr, pagesc);
- while(pagesc) {
- struct page *page;
- /* see if page is in the page cache */
- DEBUG(3, "blkmtd: write: grabbing page %d from page cachen", pagenr);
- page = grab_cache_page(&rawdevice->as, pagenr);
- DEBUG(3, "blkmtd: write: got page %d from page cachen", pagenr);
- if(!page) {
- printk("blkmtd: write: cant grab cache page %dn", 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 = %dn", 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 endn");
- pages[pagecnt++] = page;
- *retlen += len3;
- err = 0;
- }
- DEBUG(2, "blkmtd: write: end, retlen = %d, err = %dn", *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: calledn");
- 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 taskn");
- 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 taskn");
- goto stuff_inq;
- }
- spin_unlock(&mbd_writeq_lock);
- DEBUG(2, "blkmtd: sync: finishedn");
- }
- #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: %dnWrite queue tail: %dn"
- "Write queue count: %dnPages in queue: %d (%dK)n"
- "Clean Pages: %dnDirty Pages: %dnLocked Pages: %dn"
- "nrpages: %ldn",
- 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 %sn", 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' namen");
- 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 = %dn",
- 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 %sn", device);
- DEBUG(2, "blkmtd: filp_open returned %ldn", 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 devicen", 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 = %dn", 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 devicen");
- return 1;
- }
- DEBUG(1, "blkmtd: devname = %sn", bdevname(rdev));
- blocksize = BLOCK_SIZE;
- if(bs) {
- blocksize = bs;
- } else {
- if (blksize_size[maj] && blksize_size[maj][min]) {
- DEBUG(2, "blkmtd: blksize_size = %dn", 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 = %ldn", (long int)size);
- if(size == 0) {
- printk("blkmtd: cant determine sizen");
- 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 = %dn",
- 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 regionsn", 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 @ %pn", write_queue_task);
- DEBUG(2, "blkmtd: init: starting kernel taskn");
- kernel_thread(write_queue_task, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGHAND);
- DEBUG(2, "blkmtd: init: startedn");
- printk("blkmtd loaded: version = %s using %s erase_size = %dK %sn",
- VERSION, device, erase_size, (readonly) ? "(read-only)" : "");
- }
- #ifdef BLKMTD_PROC_DEBUG
- /* create proc entry */
- DEBUG(2, "Creating /proc/blkmtd_debugn");
- blkmtd_proc = create_proc_read_entry("blkmtd_debug", 0444,
- NULL, blkmtd_proc_read, NULL);
- if(blkmtd_proc == NULL) {
- printk("Cant create /proc/blkmtd_debugn");
- } 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);