Some news for this: [PATCH] [MTD] BLOCK_RO: Readonly Block Device Layer Over MTD ?

Gregory CLEMENT
2007-11-21T14:27:28Z

Hello,

I come back with my question because it seems that last time I sent
this mail mtd mailing list was done during few weeks, so maybe this
mail was lost.

2007/9/27, Gregory CLEMENT <gclement00@gmail.com>:
> 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@dev.rtsoft.ru>:
> > On Wed, 22 Nov 2006 19:56:33 +0300
> > Konstantin Baydarov <kbaidarov@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@dev.rtsoft.ru>
> > + * Pantelis Antoniou <panto@intracom.gr>
> > + * David Woodhouse <dwmw2@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@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
>

--
Gregory CLEMENT
Adeneo
Adetel Group
2, chemin du Ruisseau
69134 ECULLY - FRANCE
Tél. : +33 (0)4 72 18 08 40 - Fax : +33 (0)4 72 18 08 41