[PATCH] [MTD] BLOCK_RO: Readonly Block Device Layer Over MTD
Gregory CLEMENT
gclement00 at gmail.com
Thu Sep 27 11:05:40 EDT 2007
Hi,
this drivers seems pretty good and easily reviewable, so why it hadn't
been included in mtd tree ?
After some search I had not find any news on this patch, but maybe I
missed something.
2006/12/2, Konstantin Baydarov <kbaidarov at dev.rtsoft.ru>:
> On Wed, 22 Nov 2006 19:56:33 +0300
> Konstantin Baydarov <kbaidarov at dev.rtsoft.ru> wrote:
> >
> > Corrected typo, renamed driver, got rid from redundant dependency.
> > Also I've tested mtdblock_ro_bbfree as module - ok.
>
> Renamed driver to 'romblock'. Every entry of 'mtdblock' was replaced.
> Debug level in DEBUG macros was replaced by corresponding macros.
>
> drivers/mtd/Kconfig | 7 ++
> drivers/mtd/Makefile | 1
> drivers/mtd/romblock.c | 165 +++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 173 insertions(+)
>
> Index: mtd-2.6/drivers/mtd/romblock.c
> ===================================================================
> --- /dev/null
> +++ mtd-2.6/drivers/mtd/romblock.c
> @@ -0,0 +1,165 @@
> +/*
> + * Readonly Block Device Layer Over MTD
> + *
> + * (C) 2006 Baydarov Konstantin <kbaidarov at dev.rtsoft.ru>
> + * Pantelis Antoniou <panto at intracom.gr>
> + * David Woodhouse <dwmw2 at infradead.org>
> + *
> + * It allows to use any filesystem on this device in
> + * RO mode and thus gain faster mount times and better
> + * throughput rates.
> + *
> + */
> +
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/blktrans.h>
> +
> +struct romblock_map {
> + struct mtd_blktrans_dev dev;
> + /* block map for RO */
> + int32_t *block_map;
> + int32_t block_top;
> + int32_t block_scantop;
> +};
> +
> +static loff_t map_over_bad_blocks(struct mtd_blktrans_dev* dev, loff_t from)
> +{
> + int i, block;
> + struct mtd_info *mtd = dev->mtd;
> + struct romblock_map* dev_cont = container_of(dev, struct romblock_map, dev);
> + int32_t *block_map = dev_cont->block_map;
> + int32_t block_top = dev_cont->block_top;
> + int32_t block_scantop = dev_cont->block_scantop;
> +
> + /* if no bad block checking is possible bail out */
> + if (mtd->block_isbad == NULL)
> + return from;
> +
> + /* first time in */
> + if (block_map == NULL) {
> + block_top = mtd->size / mtd->erasesize;
> + block_map = kmalloc(sizeof(*block_map) * block_top, GFP_KERNEL);
> + if (block_map == NULL) {
> + printk (KERN_ERR "map_over_bad_blocks(): unable to allocate block map\n");
> + return -ENOMEM;
> + }
> + for (i = 0; i < block_top; i++)
> + block_map[i] = -1;
> +
> + for (i = 0; i < block_top; i++)
> + if ((*mtd->block_isbad)(mtd, i * mtd->erasesize) == 0)
> + break;
> +
> + if (i >= block_top) {
> + printk (KERN_WARNING "map_over_bad_blocks(): all blocks bad!\n");
> + return -EIO;
> + }
> + block_scantop = 0;
> + block_map[0] = i;
> +
> + DEBUG(MTD_DEBUG_LEVEL0, "mtd: map %d -> %d\n", block_scantop, block_map[block_scantop]);
> + }
> +
> + block = ((int)from / mtd->erasesize);
> + if (block >= block_top)
> + return (loff_t)-1;
> +
> + /* scan for bad block up to where we want */
> + while (block >= block_scantop) {
> + /* find a non bad block */
> + for (i = block_map[block_scantop] + 1; i < block_top; i++)
> + if ((*mtd->block_isbad)(mtd, i * mtd->erasesize) == 0)
> + break;
> +
> + /* exhausted ? */
> + if (i >= block_top) {
> + printk (KERN_WARNING "map_over_bad_blocks(): no more good blocks!\n");
> + return (loff_t)-1;
> + }
> +
> + block_map[++block_scantop] = i;
> + DEBUG(MTD_DEBUG_LEVEL0, "mtd: map %d -> %d\n", block_scantop, block_map[block_scantop]);
> + }
> +
> + block = block_map[(int)from / mtd->erasesize];
> + from = (block * mtd->erasesize) | ((int)from & (mtd->erasesize - 1));
> + return from;
> +}
> +
> +static int romblock_readsect(struct mtd_blktrans_dev *dev,
> + unsigned long block, char *buf)
> +{
> + size_t retlen;
> + unsigned long from;
> +
> + from = map_over_bad_blocks(dev, block<<9);
> +
> + if (dev->mtd->read(dev->mtd, from, 512, &retlen, buf))
> + return 1;
> + return 0;
> +}
> +
> +static int romblock_writesect(struct mtd_blktrans_dev *dev,
> + unsigned long block, char *buf)
> +{
> + size_t retlen;
> +
> + if (dev->mtd->write(dev->mtd, (block * 512), 512, &retlen, buf))
> + return 1;
> + return 0;
> +}
> +
> +static void romblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
> +{
> + struct romblock_map *dev_cont = kmalloc(sizeof(*dev_cont), GFP_KERNEL);
> +
> + if (!dev_cont)
> + return;
> +
> + memset(dev_cont, 0, sizeof(*dev_cont));
> +
> + dev_cont->dev.mtd = mtd;
> + dev_cont->dev.devnum = mtd->index;
> + dev_cont->dev.blksize = 512;
> + dev_cont->dev.size = mtd->size >> 9;
> + dev_cont->dev.tr = tr;
> + dev_cont->dev.readonly = 1;
> +
> + add_mtd_blktrans_dev(&(dev_cont->dev));
> +}
> +
> +static void romblock_remove_dev(struct mtd_blktrans_dev *dev)
> +{
> + del_mtd_blktrans_dev(dev);
> + kfree(dev);
> +}
> +
> +static struct mtd_blktrans_ops romblock_tr = {
> + .name = "romblock",
> + .major = 258,
> + .part_bits = 0,
> + .readsect = romblock_readsect,
> + .writesect = romblock_writesect,
> + .add_mtd = romblock_add_mtd,
> + .remove_dev = romblock_remove_dev,
> + .owner = THIS_MODULE,
> +};
> +
> +static int __init romblock_init(void)
> +{
> + return register_mtd_blktrans(&romblock_tr);
> +}
> +
> +static void __exit romblock_exit(void)
> +{
> + deregister_mtd_blktrans(&romblock_tr);
> +}
> +
> +module_init(romblock_init);
> +module_exit(romblock_exit);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Baydarov Konstantin <kbaidarov at dev.rtsoft.ru>");
> +MODULE_DESCRIPTION("Readonly Block Device Layer Over MTD");
> Index: mtd-2.6/drivers/mtd/Makefile
> ===================================================================
> --- mtd-2.6.orig/drivers/mtd/Makefile
> +++ mtd-2.6/drivers/mtd/Makefile
> @@ -17,6 +17,7 @@ obj-$(CONFIG_MTD_AFS_PARTS) += afs.o
> obj-$(CONFIG_MTD_CHAR) += mtdchar.o
> obj-$(CONFIG_MTD_BLOCK) += mtdblock.o mtd_blkdevs.o
> obj-$(CONFIG_MTD_BLOCK_RO) += mtdblock_ro.o mtd_blkdevs.o
> +obj-$(CONFIG_MTD_BLOCK_ROMBLOCK) += romblock.o mtd_blkdevs.o
> obj-$(CONFIG_FTL) += ftl.o mtd_blkdevs.o
> obj-$(CONFIG_NFTL) += nftl.o mtd_blkdevs.o
> obj-$(CONFIG_INFTL) += inftl.o mtd_blkdevs.o
> Index: mtd-2.6/drivers/mtd/Kconfig
> ===================================================================
> --- mtd-2.6.orig/drivers/mtd/Kconfig
> +++ mtd-2.6/drivers/mtd/Kconfig
> @@ -197,6 +197,13 @@ config MTD_BLOCK_RO
> You do not need this option for use with the DiskOnChip devices. For
> those, enable NFTL support (CONFIG_NFTL) instead.
>
> +config MTD_BLOCK_ROMBLOCK
> + tristate "Readonly Block Device Layer Over MTD"
> + depends on MTD_BLOCK!=y && MTD
> + help
> + Same as readonly block driver, but this allow you to mount read-only file
> + systems from an MTD device, containing bad blocks.
> +
> config FTL
> tristate "FTL (Flash Translation Layer) support"
> depends on MTD && BLOCK
>
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/
>
--
Gregory CLEMENT
Adeneo
2, chemin du Ruisseau - BP21
69136 Ecully Cedex
France
Tel : +33-4 72 18 08 40
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